damus/nostrdb/src/nostrdb.c

#include "nostrdb.h"
#include "jsmn.h"
#include "hex.h"
#include "cursor.h"
#include "random.h"
#include "ccan/crypto/sha256/sha256.h"
#include "bolt11/bolt11.h"
#include "bolt11/amount.h"
#include "lmdb.h"
#include "util.h"
#include "cpu.h"
#include "block.h"
#include "threadpool.h"
#include "thread.h"
#include "protected_queue.h"
#include "memchr.h"
#include "print_util.h"
#include <stdlib.h>
#include <limits.h>
#include <assert.h>

#include "bindings/c/profile_json_parser.h"
#include "bindings/c/profile_builder.h"
#include "bindings/c/meta_builder.h"
#include "bindings/c/meta_reader.h"
#include "bindings/c/profile_verifier.h"
#include "secp256k1.h"
#include "secp256k1_ecdh.h"
#include "secp256k1_schnorrsig.h"

#define max(a,b) ((a) > (b) ? (a) : (b))
#define min(a,b) ((a) < (b) ? (a) : (b))

// the maximum number of things threads pop and push in bulk
#define THREAD_QUEUE_BATCH 4096

// maximum number of active subscriptions
#define MAX_SUBSCRIPTIONS 256
#define MAX_SCAN_CURSORS 12
#define MAX_FILTERS    16

// the maximum size of inbox queues
static const int DEFAULT_QUEUE_SIZE = 32768;

// increase if we need bigger filters
#define NDB_FILTER_PAGES 64

#define ndb_flag_set(flags, f) ((flags & f) == f)

#define NDB_PARSED_ID           (1 << 0)
#define NDB_PARSED_PUBKEY       (1 << 1)
#define NDB_PARSED_SIG          (1 << 2)
#define NDB_PARSED_CREATED_AT   (1 << 3)
#define NDB_PARSED_KIND         (1 << 4)
#define NDB_PARSED_CONTENT      (1 << 5)
#define NDB_PARSED_TAGS         (1 << 6)
#define NDB_PARSED_ALL          (NDB_PARSED_ID|NDB_PARSED_PUBKEY|NDB_PARSED_SIG|NDB_PARSED_CREATED_AT|NDB_PARSED_KIND|NDB_PARSED_CONTENT|NDB_PARSED_TAGS)

typedef int (*ndb_migrate_fn)(struct ndb *);
typedef int (*ndb_word_parser_fn)(void *, const char *word, int word_len,
				  int word_index);

// these must be byte-aligned, they are directly accessing the serialized data
// representation
#pragma pack(push, 1)

union ndb_packed_str {
	struct {
		char str[3];
		// we assume little endian everywhere. sorry not sorry.
		unsigned char flag; // NDB_PACKED_STR, etc
	} packed;

	uint32_t offset;
	unsigned char bytes[4];
};

struct ndb_tag {
	uint16_t count;
	union ndb_packed_str strs[0];
};

struct ndb_tags {
	uint16_t padding;
	uint16_t count;
};

// v1
struct ndb_note {
	unsigned char version;    // v=1
	unsigned char padding[3]; // keep things aligned
	unsigned char id[32];
	unsigned char pubkey[32];
	unsigned char sig[64];

	uint64_t created_at;
	uint32_t kind;
	uint32_t content_length;
	union ndb_packed_str content;
	uint32_t strings;
	// nothing can come after tags since it contains variadic data
	struct ndb_tags tags;
};

#pragma pack(pop)


struct ndb_migration {
	ndb_migrate_fn fn;
};

struct ndb_profile_record_builder {
	flatcc_builder_t *builder;
	void *flatbuf;
};

// controls whether to continue or stop the json parser
enum ndb_idres {
	NDB_IDRES_CONT,
	NDB_IDRES_STOP,
};

// closure data for the id-detecting ingest controller
struct ndb_ingest_controller
{
	MDB_txn *read_txn;
	struct ndb_lmdb *lmdb;
};

enum ndb_writer_msgtype {
	NDB_WRITER_QUIT, // kill thread immediately
	NDB_WRITER_NOTE, // write a note to the db
	NDB_WRITER_PROFILE, // write a profile to the db
	NDB_WRITER_DBMETA, // write ndb metadata
	NDB_WRITER_PROFILE_LAST_FETCH, // when profiles were last fetched
	NDB_WRITER_BLOCKS, // write parsed note blocks
};

// keys used for storing data in the NDB metadata database (NDB_DB_NDB_META)
enum ndb_meta_key {
	NDB_META_KEY_VERSION = 1
};

struct ndb_json_parser {
	const char *json;
	int json_len;
	struct ndb_builder builder;
	jsmn_parser json_parser;
	jsmntok_t *toks, *toks_end;
	int i;
	int num_tokens;
};

// useful to pass to threads on its own
struct ndb_lmdb {
	MDB_env *env;
	MDB_dbi dbs[NDB_DBS];
};

struct ndb_writer {
	struct ndb_lmdb *lmdb;
	struct ndb_monitor *monitor;

	void *queue_buf;
	int queue_buflen;
	pthread_t thread_id;

	struct prot_queue inbox;
};

struct ndb_ingester {
	struct ndb_lmdb *lmdb;
	uint32_t flags;
	struct threadpool tp;
	struct prot_queue *writer_inbox;
	void *filter_context;
	ndb_ingest_filter_fn filter;
};

struct ndb_filter_group {
	struct ndb_filter filters[MAX_FILTERS];
	int num_filters;
};

struct ndb_subscription {
	uint64_t subid;
	struct ndb_filter_group group;
	struct prot_queue inbox;
};

struct ndb_monitor {
	struct ndb_subscription subscriptions[MAX_SUBSCRIPTIONS];
	ndb_sub_fn sub_cb;
	void *sub_cb_ctx;
	int num_subscriptions;

	// monitor isn't a full inbox. We want pollers to be able to poll
	// subscriptions efficiently without going through a message queue, so
	// we use a simple mutex here.
	pthread_mutex_t mutex;
};

struct ndb {
	struct ndb_lmdb lmdb;
	struct ndb_ingester ingester;
	struct ndb_monitor monitor;
	struct ndb_writer writer;
	int version;
	uint32_t flags; // setting flags
	// lmdb environ handles, etc
};

///
/// Query Plans
///
/// There are general strategies for performing certain types of query
/// depending on the filter. For example, for large contact list queries
/// with many authors, we simply do a descending scan on created_at
/// instead of doing 1000s of pubkey scans.
///
/// Query plans are calculated from filters via `ndb_filter_plan`
///
enum ndb_query_plan {
	NDB_PLAN_KINDS,
	NDB_PLAN_IDS,
	NDB_PLAN_AUTHORS,
	NDB_PLAN_CREATED,
	NDB_PLAN_TAGS,
};

// A id + u64 + timestamp
struct ndb_id_u64_ts {
	unsigned char id[32]; // pubkey, id, etc
	uint64_t u64; // kind, etc
	uint64_t timestamp;
};

// A clustered key with an id and a timestamp
struct ndb_tsid {
	unsigned char id[32];
	uint64_t timestamp;
};

// A u64 + timestamp id. Just using this for kinds at the moment.
struct ndb_u64_ts {
	uint64_t u64; // kind, etc
	uint64_t timestamp;
};

struct ndb_word
{
	const char *word;
	int word_len;
};

struct ndb_search_words
{
	struct ndb_word words[MAX_TEXT_SEARCH_WORDS];
	int num_words;
};

// ndb_text_search_key
//
// This is compressed when in lmdb:
//
//   note_id:    varint
//   strlen:     varint
//   str:        cstr
//   timestamp:  varint
//   word_index: varint
//
static int ndb_make_text_search_key(unsigned char *buf, int bufsize,
				    int word_index, int word_len, const char *str,
				    uint64_t timestamp, uint64_t note_id,
				    int *keysize)
{
	struct cursor cur;
	make_cursor(buf, buf + bufsize, &cur);

	// TODO: need update this to uint64_t
	// we push this first because our query function can pull this off
	// quickly to check matches
	if (!cursor_push_varint(&cur, (int32_t)note_id))
		return 0;

	// string length
	if (!cursor_push_varint(&cur, word_len))
		return 0;

	// non-null terminated, lowercase string
	if (!cursor_push_lowercase(&cur, str, word_len))
		return 0;

	// TODO: need update this to uint64_t
	if (!cursor_push_varint(&cur, (int)timestamp))
		return 0;

	// the index of the word in the content so that we can do more accurate
	// phrase searches
	if (!cursor_push_varint(&cur, word_index))
		return 0;

	// pad to 8-byte alignment
	if (!cursor_align(&cur, 8))
		return 0;

	*keysize = cur.p - cur.start;
	assert((*keysize % 8) == 0);

	return 1;
}

static int ndb_make_noted_text_search_key(unsigned char *buf, int bufsize,
					  int wordlen, const char *word,
					  uint64_t timestamp, uint64_t note_id,
					  int *keysize)
{
	return ndb_make_text_search_key(buf, bufsize, 0, wordlen, word,
					timestamp, note_id, keysize);
}

static int ndb_make_text_search_key_low(unsigned char *buf, int bufsize,
					int wordlen, const char *word,
					int *keysize)
{
	uint64_t timestamp, note_id;
	timestamp = 0;
	note_id = 0;
	return ndb_make_text_search_key(buf, bufsize, 0, wordlen, word,
					timestamp, note_id, keysize);
}

static int ndb_make_text_search_key_high(unsigned char *buf, int bufsize,
					 int wordlen, const char *word,
					 int *keysize)
{
	uint64_t timestamp, note_id;
	timestamp = INT32_MAX;
	note_id = INT32_MAX;
	return ndb_make_text_search_key(buf, bufsize, 0, wordlen, word,
					timestamp, note_id, keysize);
}

typedef int (*ndb_text_search_key_order_fn)(unsigned char *buf, int bufsize, int wordlen, const char *word, int *keysize);

/** From LMDB: Compare two items lexically */
static int mdb_cmp_memn(const MDB_val *a, const MDB_val *b) {
	int diff;
	ssize_t len_diff;
	unsigned int len;

	len = a->mv_size;
	len_diff = (ssize_t) a->mv_size - (ssize_t) b->mv_size;
	if (len_diff > 0) {
		len = b->mv_size;
		len_diff = 1;
	}

	diff = memcmp(a->mv_data, b->mv_data, len);
	return diff ? diff : len_diff<0 ? -1 : len_diff;
}

static int ndb_tag_key_compare(const MDB_val *a, const MDB_val *b)
{
	MDB_val va, vb;
	uint64_t ts_a, ts_b;
	int cmp;

	va.mv_data = a->mv_data;
	va.mv_size = a->mv_size - 8;

	vb.mv_data = b->mv_data;
	vb.mv_size = b->mv_size - 8;

	if ((cmp = mdb_cmp_memn(&va, &vb)))
		return cmp;

	ts_a = *(uint64_t*)((unsigned char *)va.mv_data + va.mv_size);
	ts_b = *(uint64_t*)((unsigned char *)vb.mv_data + vb.mv_size);

	if (ts_a < ts_b)
		return -1;
	else if (ts_a > ts_b)
		return 1;

	return 0;
}

static int ndb_text_search_key_compare(const MDB_val *a, const MDB_val *b)
{
	struct cursor ca, cb;
	uint64_t sa, sb, nid_a, nid_b;
	MDB_val a2, b2;

	make_cursor(a->mv_data, (unsigned char *)a->mv_data + a->mv_size, &ca);
	make_cursor(b->mv_data, (unsigned char *)b->mv_data + b->mv_size, &cb);

	// note_id
	if (unlikely(!cursor_pull_varint(&ca, &nid_a) || !cursor_pull_varint(&cb, &nid_b)))
		return 0;

	// string size
	if (unlikely(!cursor_pull_varint(&ca, &sa) || !cursor_pull_varint(&cb, &sb)))
		return 0;

	a2.mv_data = ca.p;
	a2.mv_size = sa;

	b2.mv_data = cb.p;
	b2.mv_size = sb;

	int cmp = mdb_cmp_memn(&a2, &b2);
	if (cmp) return cmp;

	// skip over string
	ca.p += sa;
	cb.p += sb;

	// timestamp
	if (unlikely(!cursor_pull_varint(&ca, &sa) || !cursor_pull_varint(&cb, &sb)))
		return 0;

	if      (sa < sb) return -1;
	else if (sa > sb) return 1;

	// note_id
	if      (nid_a < nid_b) return -1;
	else if (nid_a > nid_b) return 1;

	// word index
	if (unlikely(!cursor_pull_varint(&ca, &sa) || !cursor_pull_varint(&cb, &sb)))
		return 0;

	if      (sa < sb) return -1;
	else if (sa > sb) return 1;

	return 0;
}

static inline int ndb_unpack_text_search_key_noteid(
		struct cursor *cur, uint64_t *note_id)
{
	if (!cursor_pull_varint(cur, note_id))
		return 0;

	return 1;
}

// faster peek of just the string instead of unpacking everything
// this is used to quickly discard range query matches if there is no
// common prefix
static inline int ndb_unpack_text_search_key_string(struct cursor *cur,
						    const char **str,
						    int *str_len)
{
	uint64_t len;

	if (!cursor_pull_varint(cur, &len))
		return 0;

	*str_len = len;

	*str = (const char *)cur->p;

	if (!cursor_skip(cur, *str_len))
		return 0;

	return 1;
}

// should be called after ndb_unpack_text_search_key_string. It continues
// the unpacking of a text search key if we've already started it.
static inline int
ndb_unpack_remaining_text_search_key(struct cursor *cur,
				     struct ndb_text_search_key *key)
{
	if (!cursor_pull_varint(cur, &key->timestamp))
		return 0;

	if (!cursor_pull_varint(cur, &key->word_index))
		return 0;

	return 1;
}

// unpack a fulltext search key
//
// full version of string + unpack remaining. This is split up because text
// searching only requires to pull the string for prefix searching, and the
// remaining is optional
static inline int ndb_unpack_text_search_key(unsigned char *p, int len,
				      struct ndb_text_search_key *key)
{
	struct cursor c;
	make_cursor(p, p + len, &c);

	if (!ndb_unpack_text_search_key_noteid(&c, &key->note_id))
		return 0;

	if (!ndb_unpack_text_search_key_string(&c, &key->str, &key->str_len))
		return 0;

	return ndb_unpack_remaining_text_search_key(&c, key);
}

// Copies only lowercase characters to the destination string and fills the rest with null bytes.
// `dst` and `src` are pointers to the destination and source strings, respectively.
// `n` is the maximum number of characters to copy.
static void lowercase_strncpy(char *dst, const char *src, int n) {
	int j = 0, i = 0;

	if (!dst || !src || n == 0) {
		return;
	}

	while (src[i] != '\0' && j < n) {
		dst[j++] = tolower(src[i++]);
	}

	// Null-terminate and fill the destination string
	while (j < n) {
		dst[j++] = '\0';
	}
}

static inline int ndb_filter_elem_is_ptr(struct ndb_filter_field *field) {
	return field->elem_type == NDB_ELEMENT_STRING || field->elem_type == NDB_ELEMENT_ID;
}

// Copy the filter
int ndb_filter_clone(struct ndb_filter *dst, struct ndb_filter *src)
{
	size_t src_size, elem_size, data_size;

	memcpy(dst, src, sizeof(*src));

	elem_size = src->elem_buf.end - src->elem_buf.start;
	data_size = src->data_buf.end - src->data_buf.start;
	src_size = data_size + elem_size;

	// let's only allow finalized filters to be cloned
	if (!src || !src->finalized)
		return 0;

	dst->elem_buf.start = malloc(src_size);
	dst->elem_buf.end = dst->elem_buf.start + elem_size;
	dst->elem_buf.p = dst->elem_buf.end;

	dst->data_buf.start = dst->elem_buf.start + elem_size;
	dst->data_buf.end = dst->data_buf.start + data_size;
	dst->data_buf.p = dst->data_buf.end;

	if (dst->elem_buf.start == NULL)
		return 0;

	memcpy(dst->elem_buf.start, src->elem_buf.start, src_size);

	return 1;
}

// "Finalize" the filter. This resizes the allocated heap buffers so that they
// are as small as possible. This also prevents new fields from being added
int ndb_filter_end(struct ndb_filter *filter)
{
#ifdef DEBUG
	size_t orig_size;
#endif
	size_t data_len, elem_len;
	if (filter->finalized == 1)
		return 0;

	// move the data buffer to the end of the element buffer and update
	// all of the element pointers accordingly
	data_len = filter->data_buf.p - filter->data_buf.start;
	elem_len = filter->elem_buf.p - filter->elem_buf.start;
#ifdef DEBUG
	orig_size = filter->data_buf.end - filter->elem_buf.start;
#endif

	// cap the elem buff
	filter->elem_buf.end = filter->elem_buf.p;

	// move the data buffer to the end of the element buffer
	memmove(filter->elem_buf.p, filter->data_buf.start, data_len);

	// realloc the whole thing
	filter->elem_buf.start = realloc(filter->elem_buf.start, elem_len + data_len);
	filter->elem_buf.end = filter->elem_buf.start + elem_len;
	filter->elem_buf.p = filter->elem_buf.end;

	filter->data_buf.start = filter->elem_buf.end;
	filter->data_buf.end = filter->data_buf.start + data_len;
	filter->data_buf.p = filter->data_buf.end;

	filter->finalized = 1;

	ndb_debug("ndb_filter_end: %ld -> %ld\n", orig_size, elem_len + data_len);

	return 1;
}

static inline struct ndb_filter_elements *
ndb_filter_get_elements_by_offset(const struct ndb_filter *filter, int offset)
{
	struct ndb_filter_elements *els;

	if (offset < 0)
		return NULL;

	els = (struct ndb_filter_elements *)(filter->elem_buf.start + offset);

	if ((unsigned char *)els > filter->elem_buf.p)
		return NULL;

	return els;
}

struct ndb_filter_elements *
ndb_filter_current_element(const struct ndb_filter *filter)
{
	return ndb_filter_get_elements_by_offset(filter, filter->current);
}

struct ndb_filter_elements *
ndb_filter_get_elements(const struct ndb_filter *filter, int index)
{
	if (filter->num_elements <= 0)
		return NULL;

	if (index > filter->num_elements-1)
		return NULL;

	return ndb_filter_get_elements_by_offset(filter, filter->elements[index]);
}

static inline unsigned char *
ndb_filter_elements_data(const struct ndb_filter *filter, int offset)
{
	unsigned char *data;

	if (offset < 0)
		return NULL;

	data = filter->data_buf.start + offset;
	if (data > filter->data_buf.p)
		return NULL;

	return data;
}

unsigned char *
ndb_filter_get_id_element(const struct ndb_filter *filter, const struct ndb_filter_elements *els, int index)
{
	return ndb_filter_elements_data(filter, els->elements[index]);
}

const char *
ndb_filter_get_string_element(const struct ndb_filter *filter, const struct ndb_filter_elements *els, int index)
{
	return (const char *)ndb_filter_elements_data(filter, els->elements[index]);
}

uint64_t *
ndb_filter_get_int_element_ptr(struct ndb_filter_elements *els, int index)
{
	return &els->elements[index];
}

uint64_t
ndb_filter_get_int_element(const struct ndb_filter_elements *els, int index)
{
	return els->elements[index];
}

int ndb_filter_init(struct ndb_filter *filter)
{
	struct cursor cur;
	int page_size, elem_pages, data_pages, buf_size;

	page_size = 4096; // assuming this, not a big deal if we're wrong
	elem_pages = NDB_FILTER_PAGES / 4;
	data_pages = NDB_FILTER_PAGES - elem_pages;
	buf_size = page_size * NDB_FILTER_PAGES;

	unsigned char *buf = malloc(buf_size);
	if (!buf)
		return 0;

	// init memory arena for the cursor
	make_cursor(buf, buf + buf_size, &cur);

	cursor_slice(&cur, &filter->elem_buf, page_size * elem_pages);
	cursor_slice(&cur, &filter->data_buf, page_size * data_pages);

	// make sure we are fully allocated
	assert(cur.p == cur.end);

	// make sure elem_buf is the start of the buffer
	assert(filter->elem_buf.start == cur.start);

	filter->num_elements = 0;
	filter->elements[0] = 0;
	filter->current = -1;
	filter->finalized = 0;

	return 1;
}

void ndb_filter_destroy(struct ndb_filter *filter)
{
	if (filter->elem_buf.start)
		free(filter->elem_buf.start);

	memset(filter, 0, sizeof(*filter));
}

static const char *ndb_filter_field_name(enum ndb_filter_fieldtype field)
{
	switch (field) {
	case NDB_FILTER_IDS: return "ids";
	case NDB_FILTER_AUTHORS: return "authors";
	case NDB_FILTER_KINDS: return "kinds";
	case NDB_FILTER_TAGS: return "tags";
	case NDB_FILTER_SINCE: return "since";
	case NDB_FILTER_UNTIL: return "until";
	case NDB_FILTER_LIMIT: return "limit";
	}

	return "unknown";
}

static int ndb_filter_start_field_impl(struct ndb_filter *filter, enum ndb_filter_fieldtype field, char tag)
{
	int i;
	struct ndb_filter_elements *els, *el;

	if (ndb_filter_current_element(filter)) {
		fprintf(stderr, "ndb_filter_start_field: filter field already in progress, did you forget to call ndb_filter_end_field?\n");
		return 0;
	}

	// you can only start and end fields once
	for (i = 0; i < filter->num_elements; i++) {
		el = ndb_filter_get_elements(filter, i);
		assert(el);
		// TODO: fix this tags check to try to find matching tags
		if (el->field.type == field && field != NDB_FILTER_TAGS) {
			fprintf(stderr, "ndb_filter_start_field: field '%s' already exists\n",
					ndb_filter_field_name(field));
			return 0;
		}
	}

	filter->current = filter->elem_buf.p - filter->elem_buf.start;
	els = ndb_filter_current_element(filter);
	assert(els);

	// advance elem buffer to the variable data section
	if (!cursor_skip(&filter->elem_buf, sizeof(struct ndb_filter_elements))) {
		fprintf(stderr, "ndb_filter_start_field: '%s' oom (todo: realloc?)\n",
				ndb_filter_field_name(field));
		return 0;
	}

	els->field.type = field;
	els->field.tag = tag;
	els->field.elem_type = 0;
	els->count = 0;

	return 1;
}

int ndb_filter_start_field(struct ndb_filter *filter, enum ndb_filter_fieldtype field)
{
	return ndb_filter_start_field_impl(filter, field, 0);
}

int ndb_filter_start_tag_field(struct ndb_filter *filter, char tag)
{
	return ndb_filter_start_field_impl(filter, NDB_FILTER_TAGS, tag);
}

static int ndb_filter_add_element(struct ndb_filter *filter, union ndb_filter_element el)
{
	struct ndb_filter_elements *current;
	uint64_t offset;

	if (!(current = ndb_filter_current_element(filter)))
		return 0;

	offset = filter->data_buf.p - filter->data_buf.start;

	switch (current->field.type) {
	case NDB_FILTER_IDS:
	case NDB_FILTER_AUTHORS:
		if (!cursor_push(&filter->data_buf, (unsigned char *)el.id, 32))
			return 0;
		break;
	case NDB_FILTER_KINDS:
		offset = el.integer;
		break;
	case NDB_FILTER_SINCE:
	case NDB_FILTER_UNTIL:
	case NDB_FILTER_LIMIT:
		// only one allowed for since/until
		if (current->count != 0)
			return 0;
		offset = el.integer;
		break;
	case NDB_FILTER_TAGS:
		switch (current->field.elem_type) {
		case NDB_ELEMENT_ID:
			if (!cursor_push(&filter->data_buf, (unsigned char *)el.id, 32))
				return 0;
			break;
		case NDB_ELEMENT_STRING:
			if (!cursor_push(&filter->data_buf, (unsigned char *)el.string.string, el.string.len))
				return 0;
			if (!cursor_push_byte(&filter->data_buf, 0))
				return 0;
			break;
		case NDB_ELEMENT_INT:
			// ints are not allowed in tag filters
		case NDB_ELEMENT_UNKNOWN:
			return 0;
		}
		// push a pointer of the string in the databuf as an element
		break;
	}

	if (!cursor_push(&filter->elem_buf, (unsigned char *)&offset,
			 sizeof(offset))) {
		return 0;
	}

	current->count++;

	return 1;
}

static int ndb_filter_set_elem_type(struct ndb_filter *filter,
				    enum ndb_generic_element_type elem_type)
{
	enum ndb_generic_element_type current_elem_type;
	struct ndb_filter_elements *current;

	if (!(current = ndb_filter_current_element(filter)))
		return 0;

	current_elem_type = current->field.elem_type;

	// element types must be uniform
	if (current_elem_type != elem_type && current_elem_type != NDB_ELEMENT_UNKNOWN) {
		fprintf(stderr, "ndb_filter_set_elem_type: element types must be uniform\n");
		return 0;
	}

	current->field.elem_type = elem_type;

	return 1;
}


int ndb_filter_add_str_element_len(struct ndb_filter *filter, const char *str, int len)
{
	union ndb_filter_element el;
	struct ndb_filter_elements *current;

	if (!(current = ndb_filter_current_element(filter)))
		return 0;

	// only generic queries are allowed to have strings
	switch (current->field.type) {
	case NDB_FILTER_SINCE:
	case NDB_FILTER_UNTIL:
	case NDB_FILTER_LIMIT:
	case NDB_FILTER_IDS:
	case NDB_FILTER_AUTHORS:
	case NDB_FILTER_KINDS:
		return 0;
	case NDB_FILTER_TAGS:
		break;
	}

	if (!ndb_filter_set_elem_type(filter, NDB_ELEMENT_STRING))
		return 0;

	el.string.string = str;
	el.string.len = len;

	return ndb_filter_add_element(filter, el);
}

int ndb_filter_add_str_element(struct ndb_filter *filter, const char *str)
{
	return ndb_filter_add_str_element_len(filter, str, strlen(str));
}

int ndb_filter_add_int_element(struct ndb_filter *filter, uint64_t integer)
{
	union ndb_filter_element el;
	struct ndb_filter_elements *current;
	if (!(current = ndb_filter_current_element(filter)))
		return 0;

	switch (current->field.type) {
	case NDB_FILTER_IDS:
	case NDB_FILTER_AUTHORS:
	case NDB_FILTER_TAGS:
		return 0;
	case NDB_FILTER_KINDS:
	case NDB_FILTER_SINCE:
	case NDB_FILTER_UNTIL:
	case NDB_FILTER_LIMIT:
		break;
	}

	if (!ndb_filter_set_elem_type(filter, NDB_ELEMENT_INT))
		return 0;

	el.integer = integer;

	return ndb_filter_add_element(filter, el);
}

int ndb_filter_add_id_element(struct ndb_filter *filter, const unsigned char *id)
{
	union ndb_filter_element el;
	struct ndb_filter_elements *current;

	if (!(current = ndb_filter_current_element(filter)))
		return 0;

	// only certain filter types allow pushing id elements
	switch (current->field.type) {
	case NDB_FILTER_SINCE:
	case NDB_FILTER_UNTIL:
	case NDB_FILTER_LIMIT:
	case NDB_FILTER_KINDS:
		return 0;
	case NDB_FILTER_IDS:
	case NDB_FILTER_AUTHORS:
	case NDB_FILTER_TAGS:
		break;
	}

	if (!ndb_filter_set_elem_type(filter, NDB_ELEMENT_ID))
		return 0;

	// this is needed so that generic filters know its an id
	el.id = id;

	return ndb_filter_add_element(filter, el);
}

static int ndb_tag_filter_matches(struct ndb_filter *filter,
				  struct ndb_filter_elements *els,
				  struct ndb_note *note)
{
	int i;
	const unsigned char *id;
	const char *el_str;
	struct ndb_iterator iter, *it = &iter;
	struct ndb_str str;

	ndb_tags_iterate_start(note, it);

	while (ndb_tags_iterate_next(it)) {
		// we're looking for tags with 2 or more entries: ["p", id], etc
		if (it->tag->count < 2)
			continue;

		str = ndb_tag_str(note, it->tag, 0);

		// we only care about packed strings (single char, etc)
		if (str.flag != NDB_PACKED_STR)
			continue;

		// do we have #e matching e (or p, etc)
		if (str.str[0] != els->field.tag || str.str[1] != 0)
			continue;

		str = ndb_tag_str(note, it->tag, 1);

		switch (els->field.elem_type) {
		case NDB_ELEMENT_ID:
			// if our filter element type is an id, then we
			// expect a packed id in the tag, otherwise skip
			if (str.flag != NDB_PACKED_ID)
				continue;
			break;
		case NDB_ELEMENT_STRING:
			// if our filter element type is a string, then
			// we should not expect an id
			if (str.flag == NDB_PACKED_ID)
				continue;

			break;
		case NDB_ELEMENT_UNKNOWN:
		default:
			// For some reason the element type is not set. It's
			// possible nothing was added to the generic filter?
			// Let's just fail here and log a note for debugging
			fprintf(stderr, "UNUSUAL ndb_tag_filter_matches: have unknown element type %d\n", els->field.elem_type);
			return 0;
		}

		for (i = 0; i < els->count; i++) {
			switch (els->field.elem_type) {
			case NDB_ELEMENT_ID:
				id = ndb_filter_get_id_element(filter, els, i);
				if (!memcmp(id, str.id, 32))
					return 1;
				break;
			case NDB_ELEMENT_STRING:
				el_str = ndb_filter_get_string_element(filter, els, i);
				if (!strcmp(el_str, str.str))
					return 1;
				break;
			case NDB_ELEMENT_INT:
				// int elements int tag queries are not supported
			case NDB_ELEMENT_UNKNOWN:
				return 0;
			}
		}
	}

	return 0;
}

struct search_id_state {
	struct ndb_filter *filter;
	struct ndb_filter_elements *els;
	unsigned char *key;
};

static int compare_ids(const void *pa, const void *pb)
{
        unsigned char *a = *(unsigned char **)pa;
        unsigned char *b = *(unsigned char **)pb;

        return memcmp(a, b, 32);
}

static int search_ids(const void *ctx, const void *mid_ptr)
{
	struct search_id_state *state;
	unsigned char *mid_id;
	uint32_t mid;

	state = (struct search_id_state *)ctx;
	mid = *(uint32_t *)mid_ptr;

	mid_id = ndb_filter_elements_data(state->filter, mid);
	assert(mid_id);

	return memcmp(state->key, mid_id, 32);
}

static int compare_kinds(const void *pa, const void *pb)
{

	// NOTE: this should match type in `union ndb_filter_element`
	uint64_t a = *(uint64_t *)pa;
	uint64_t b = *(uint64_t *)pb;

	if (a < b) {
		return -1;
	} else if (a > b) {
		return 1;
	} else {
		return 0;
	}
}

//
// returns 1 if a filter matches a note
static int ndb_filter_matches_with(struct ndb_filter *filter,
				   struct ndb_note *note, int already_matched)
{
	int i, j;
	struct ndb_filter_elements *els;
	struct search_id_state state;

	state.filter = filter;

	for (i = 0; i < filter->num_elements; i++) {
		els = ndb_filter_get_elements(filter, i);
		state.els = els;
		assert(els);

		// if we know we already match from a query scan result,
		// we can skip this check
		if ((1 << els->field.type) & already_matched)
			continue;

		switch (els->field.type) {
		case NDB_FILTER_KINDS:
			for (j = 0; j < els->count; j++) {
				if ((unsigned int)els->elements[j] == note->kind)
					goto cont;
			}
			break;
		case NDB_FILTER_IDS:
			state.key = ndb_note_id(note);
			if (bsearch(&state, &els->elements[0], els->count,
				    sizeof(els->elements[0]), search_ids)) {
				continue;
			}
			break;
		case NDB_FILTER_AUTHORS:
			state.key = ndb_note_pubkey(note);
			if (bsearch(&state, &els->elements[0], els->count,
				    sizeof(els->elements[0]), search_ids)) {
				continue;
			}
			break;
		case NDB_FILTER_TAGS:
			if (ndb_tag_filter_matches(filter, els, note))
				continue;
			break;
		case NDB_FILTER_SINCE:
			assert(els->count == 1);
			if (note->created_at >= els->elements[0])
				continue;
			break;
		case NDB_FILTER_UNTIL:
			assert(els->count == 1);
			if (note->created_at < els->elements[0])
				continue;
		case NDB_FILTER_LIMIT:
cont:
			continue;
		}

		// all need to match
		return 0;
	}

	return 1;
}

int ndb_filter_matches(struct ndb_filter *filter, struct ndb_note *note)
{
	return ndb_filter_matches_with(filter, note, 0);
}

// because elements are stored as offsets and qsort doesn't support context,
// we do a dumb thing where we convert elements to pointers and back if we
// are doing an id or string sort
static void sort_filter_elements(struct ndb_filter *filter,
				 struct ndb_filter_elements *els,
				 int (*cmp)(const void *, const void *))
{
	int i;

	assert(ndb_filter_elem_is_ptr(&els->field));

	for (i = 0; i < els->count; i++)
		els->elements[i] += (uint64_t)filter->data_buf.start;

	qsort(&els->elements[0], els->count, sizeof(els->elements[0]), cmp);

	for (i = 0; i < els->count; i++)
		els->elements[i] -= (uint64_t)filter->data_buf.start;
}

static int ndb_filter_field_eq(struct ndb_filter *a_filt,
			       struct ndb_filter_elements *a_field,
			       struct ndb_filter *b_filt,
			       struct ndb_filter_elements *b_field)
{
	int i;
	const char *a_str, *b_str;
	unsigned char *a_id, *b_id;
	uint64_t a_int, b_int;

	if (a_field->count != b_field->count)
		return 0;

	if (a_field->field.type != b_field->field.type) {
		ndb_debug("UNUSUAL: field types do not match in ndb_filter_field_eq\n");
		return 0;
	}

	if (a_field->field.elem_type != b_field->field.elem_type) {
		ndb_debug("UNUSUAL: field element types do not match in ndb_filter_field_eq\n");
		return 0;
	}

	if (a_field->field.elem_type == NDB_ELEMENT_UNKNOWN) {
		ndb_debug("UNUSUAL: field element types are unknown\n");
		return 0;
	}

	for (i = 0; i < a_field->count; i++) {
		switch (a_field->field.elem_type) {
		case NDB_ELEMENT_UNKNOWN:
			return 0;
		case NDB_ELEMENT_STRING:
			a_str = ndb_filter_get_string_element(a_filt, a_field, i);
			b_str = ndb_filter_get_string_element(b_filt, b_field, i);
			if (strcmp(a_str, b_str))
				return 0;
			break;
		case NDB_ELEMENT_ID:
			a_id = ndb_filter_get_id_element(a_filt, a_field, i);
			b_id = ndb_filter_get_id_element(b_filt, b_field, i);
			if (memcmp(a_id, b_id, 32))
				return 0;
			break;
		case NDB_ELEMENT_INT:
			a_int = ndb_filter_get_int_element(a_field, i);
			b_int = ndb_filter_get_int_element(b_field, i);
			if (a_int != b_int)
				return 0;
			break;
		}
	}

	return 1;
}

void ndb_filter_end_field(struct ndb_filter *filter)
{
	int cur_offset;
	struct ndb_filter_elements *cur;

	cur_offset = filter->current;

	if (!(cur = ndb_filter_current_element(filter)))
		return;

	filter->elements[filter->num_elements++] = cur_offset;

	// sort elements for binary search
	switch (cur->field.type) {
	case NDB_FILTER_IDS:
	case NDB_FILTER_AUTHORS:
		sort_filter_elements(filter, cur, compare_ids);
		break;
	case NDB_FILTER_KINDS:
		qsort(&cur->elements[0], cur->count,
		      sizeof(cur->elements[0]), compare_kinds);
		break;
	case NDB_FILTER_TAGS:
		// TODO: generic tag search sorting
		break;
	case NDB_FILTER_SINCE:
	case NDB_FILTER_UNTIL:
	case NDB_FILTER_LIMIT:
		// don't need to sort these
		break;
	}

	filter->current = -1;

}

static void ndb_filter_group_init(struct ndb_filter_group *group)
{
	group->num_filters = 0;
}

static int ndb_filter_group_add(struct ndb_filter_group *group,
				struct ndb_filter *filter)
{
	if (group->num_filters + 1 > MAX_FILTERS)
		return 0;

	return ndb_filter_clone(&group->filters[group->num_filters++], filter);
}

static int ndb_filter_group_matches(struct ndb_filter_group *group,
				    struct ndb_note *note)
{
	int i;
	struct ndb_filter *filter;

	if (group->num_filters == 0)
		return 1;

	for (i = 0; i < group->num_filters; i++) {
		filter = &group->filters[i];

		if (ndb_filter_matches(filter, note))
			return 1;
	}

	return 0;
}

static void ndb_make_search_key(struct ndb_search_key *key, unsigned char *id,
			        uint64_t timestamp, const char *search)
{
	memcpy(key->id, id, 32);
	key->timestamp = timestamp;
	lowercase_strncpy(key->search, search, sizeof(key->search) - 1);
	key->search[sizeof(key->search) - 1] = '\0';
}

static int ndb_write_profile_search_index(struct ndb_txn *txn,
					  struct ndb_search_key *index_key,
					  uint64_t profile_key)
{
	int rc;
	MDB_val key, val;

	key.mv_data = index_key;
	key.mv_size = sizeof(*index_key);
	val.mv_data = &profile_key;
	val.mv_size = sizeof(profile_key);

	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_SEARCH],
			  &key, &val, 0)))
	{
		ndb_debug("ndb_write_profile_search_index failed: %s\n",
			  mdb_strerror(rc));
		return 0;
	}

	return 1;
}


// map usernames and display names to profile keys for user searching
static int ndb_write_profile_search_indices(struct ndb_txn *txn,
					    struct ndb_note *note,
					    uint64_t profile_key,
					    void *profile_root)
{
	struct ndb_search_key index;
	NdbProfileRecord_table_t profile_record;
	NdbProfile_table_t profile;

	profile_record = NdbProfileRecord_as_root(profile_root);
	profile = NdbProfileRecord_profile_get(profile_record);

	const char *name = NdbProfile_name_get(profile);
	const char *display_name = NdbProfile_display_name_get(profile);

	// words + pubkey + created
	if (name) {
		ndb_make_search_key(&index, note->pubkey, note->created_at,
				    name);
		if (!ndb_write_profile_search_index(txn, &index, profile_key))
			return 0;
	}

	if (display_name) {
		// don't write the same name/display_name twice
		if (name && !strcmp(display_name, name)) {
			return 1;
		}
		ndb_make_search_key(&index, note->pubkey, note->created_at,
				    display_name);
		if (!ndb_write_profile_search_index(txn, &index, profile_key))
			return 0;
	}

	return 1;
}

static inline void ndb_tsid_init(struct ndb_tsid *key, unsigned char *id,
				 uint64_t timestamp)
{
	memcpy(key->id, id, 32);
	key->timestamp = timestamp;
}

static inline void ndb_tsid_low(struct ndb_tsid *key, unsigned char *id)
{
	memcpy(key->id, id, 32);
	key->timestamp = 0;
}

static inline void ndb_u64_ts_init(struct ndb_u64_ts *key, uint64_t integer,
				     uint64_t timestamp)
{
	key->u64 = integer;
	key->timestamp = timestamp;
}

// useful for range-searching for the latest key with a clustered created_at timen
static inline void ndb_tsid_high(struct ndb_tsid *key, const unsigned char *id)
{
	memcpy(key->id, id, 32);
	key->timestamp = UINT64_MAX;
}

static int _ndb_begin_query(struct ndb *ndb, struct ndb_txn *txn, int flags)
{
	txn->lmdb = &ndb->lmdb;
	MDB_txn **mdb_txn = (MDB_txn **)&txn->mdb_txn;
	if (!txn->lmdb->env)
		return 0;
	return mdb_txn_begin(txn->lmdb->env, NULL, flags, mdb_txn) == 0;
}

int ndb_begin_query(struct ndb *ndb, struct ndb_txn *txn)
{
	return _ndb_begin_query(ndb, txn, MDB_RDONLY);
}

// this should only be used in migrations, etc
static int ndb_begin_rw_query(struct ndb *ndb, struct ndb_txn *txn)
{
	return _ndb_begin_query(ndb, txn, 0);
}

static inline void ndb_id_u64_ts_init(struct ndb_id_u64_ts *key,
				      unsigned char *id, uint64_t iu64,
				      uint64_t timestamp)
{
	memcpy(key->id, id, 32);
	key->u64 = iu64;
	key->timestamp = timestamp;
}

// Migrations
//

static int ndb_migrate_user_search_indices(struct ndb *ndb)
{
	int rc;
	MDB_cursor *cur;
	MDB_val k, v;
	void *profile_root;
	NdbProfileRecord_table_t record;
	struct ndb_txn txn;
	struct ndb_note *note;
	uint64_t note_key, profile_key;
	size_t len;
	int count;

	if (!ndb_begin_rw_query(ndb, &txn)) {
		fprintf(stderr, "ndb_migrate_user_search_indices: ndb_begin_rw_query failed\n");
		return 0;
	}

	if ((rc = mdb_cursor_open(txn.mdb_txn, ndb->lmdb.dbs[NDB_DB_PROFILE], &cur))) {
		fprintf(stderr, "ndb_migrate_user_search_indices: mdb_cursor_open failed, error %d\n", rc);
		return 0;
	}

	count = 0;

	// loop through all profiles and write search indices
	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
		profile_root = v.mv_data;
		profile_key = *((uint64_t*)k.mv_data);
		record = NdbProfileRecord_as_root(profile_root);
		note_key = NdbProfileRecord_note_key(record);
		note = ndb_get_note_by_key(&txn, note_key, &len);

		if (note == NULL) {
			fprintf(stderr, "ndb_migrate_user_search_indices: note lookup failed\n");
			return 0;
		}

		if (!ndb_write_profile_search_indices(&txn, note, profile_key,
						      profile_root)) {

			fprintf(stderr, "ndb_migrate_user_search_indices: ndb_write_profile_search_indices failed\n");
			return 0;
		}

		count++;
	}

	fprintf(stderr, "migrated %d profiles to include search indices\n", count);

	mdb_cursor_close(cur);

	ndb_end_query(&txn);

	return 1;
}

static int ndb_migrate_lower_user_search_indices(struct ndb *ndb)
{
	MDB_txn *txn;

	if (mdb_txn_begin(ndb->lmdb.env, NULL, 0, &txn)) {
		fprintf(stderr, "ndb_migrate_lower_user_search_indices: ndb_txn_begin failed\n");
		return 0;
	}

	// just drop the search db so we can rebuild it
	if (mdb_drop(txn, ndb->lmdb.dbs[NDB_DB_PROFILE_SEARCH], 0)) {
		fprintf(stderr, "ndb_migrate_lower_user_search_indices: mdb_drop failed\n");
		return 0;
	}

	mdb_txn_commit(txn);

	return ndb_migrate_user_search_indices(ndb);
}

int ndb_process_profile_note(struct ndb_note *note, struct ndb_profile_record_builder *profile);


int ndb_db_version(struct ndb *ndb)
{
	int rc;
	uint64_t version, version_key;
	MDB_val k, v;
	MDB_txn *txn;

	version_key = NDB_META_KEY_VERSION;
	k.mv_data = &version_key;
	k.mv_size = sizeof(version_key);

	if ((rc = mdb_txn_begin(ndb->lmdb.env, NULL, 0, &txn))) {
		fprintf(stderr, "ndb_db_version: mdb_txn_begin failed, error %d\n", rc);
		return -1;
	}

	if (mdb_get(txn, ndb->lmdb.dbs[NDB_DB_NDB_META], &k, &v)) {
		version = -1;
	} else {
		if (v.mv_size != 8) {
			fprintf(stderr, "run_migrations: invalid version size?");
			return 0;
		}
		version = *((uint64_t*)v.mv_data);
	}

	mdb_txn_abort(txn);
	return version;
}

// custom pubkey+kind+timestamp comparison function. This is used by lmdb to
// perform b+ tree searches over the pubkey+kind+timestamp index
static int ndb_id_u64_ts_compare(const MDB_val *a, const MDB_val *b)
{
	struct ndb_id_u64_ts *tsa, *tsb;
	MDB_val a2 = *a, b2 = *b;

	a2.mv_size = sizeof(tsa->id);
	b2.mv_size = sizeof(tsb->id);

	int cmp = mdb_cmp_memn(&a2, &b2);
	if (cmp) return cmp;

	tsa = a->mv_data;
	tsb = b->mv_data;

	if (tsa->u64 < tsb->u64)
		return -1;
	else if (tsa->u64 > tsb->u64)
		return 1;

	if (tsa->timestamp < tsb->timestamp)
		return -1;
	else if (tsa->timestamp > tsb->timestamp)
		return 1;

	return 0;
}

// custom kind+timestamp comparison function. This is used by lmdb to perform
// b+ tree searches over the kind+timestamp index
static int ndb_u64_ts_compare(const MDB_val *a, const MDB_val *b)
{
	struct ndb_u64_ts *tsa, *tsb;
	tsa = a->mv_data;
	tsb = b->mv_data;

	if (tsa->u64 < tsb->u64)
		return -1;
	else if (tsa->u64 > tsb->u64)
		return 1;

	if (tsa->timestamp < tsb->timestamp)
		return -1;
	else if (tsa->timestamp > tsb->timestamp)
		return 1;

	return 0;
}

static int ndb_tsid_compare(const MDB_val *a, const MDB_val *b)
{
	struct ndb_tsid *tsa, *tsb;
	MDB_val a2 = *a, b2 = *b;

	a2.mv_size = sizeof(tsa->id);
	b2.mv_size = sizeof(tsb->id);

	int cmp = mdb_cmp_memn(&a2, &b2);
	if (cmp) return cmp;

	tsa = a->mv_data;
	tsb = b->mv_data;

	if (tsa->timestamp < tsb->timestamp)
		return -1;
	else if (tsa->timestamp > tsb->timestamp)
		return 1;
	return 0;
}

enum ndb_ingester_msgtype {
	NDB_INGEST_EVENT, // write json to the ingester queue for processing
	NDB_INGEST_QUIT,  // kill ingester thread immediately
};

struct ndb_ingester_event {
	char *json;
	unsigned client : 1; // ["EVENT", {...}] messages
	unsigned len : 31;
};

struct ndb_writer_note {
	struct ndb_note *note;
	size_t note_len;
};

struct ndb_writer_profile {
	struct ndb_writer_note note;
	struct ndb_profile_record_builder record;
};

struct ndb_ingester_msg {
	enum ndb_ingester_msgtype type;
	union {
		struct ndb_ingester_event event;
	};
};

struct ndb_writer_ndb_meta {
	// these are 64 bit because I'm paranoid of db-wide alignment issues
	uint64_t version;
};

// Used in the writer thread when writing ndb_profile_fetch_record's
//   kv = pubkey: recor
struct ndb_writer_last_fetch {
	unsigned char pubkey[32];
	uint64_t fetched_at;
};

// write note blocks
struct ndb_writer_blocks {
	struct ndb_blocks *blocks;
	uint64_t note_key;
};

// The different types of messages that the writer thread can write to the
// database
struct ndb_writer_msg {
	enum ndb_writer_msgtype type;
	union {
		struct ndb_writer_note note;
		struct ndb_writer_profile profile;
		struct ndb_writer_ndb_meta ndb_meta;
		struct ndb_writer_last_fetch last_fetch;
		struct ndb_writer_blocks blocks;
	};
};

static inline int ndb_writer_queue_msg(struct ndb_writer *writer,
				       struct ndb_writer_msg *msg)
{
	return prot_queue_push(&writer->inbox, msg);
}

static int ndb_migrate_utf8_profile_names(struct ndb *ndb)
{
	int rc;
	MDB_cursor *cur;
	MDB_val k, v;
	void *profile_root;
	NdbProfileRecord_table_t record;
	struct ndb_txn txn;
	struct ndb_note *note, *copied_note;
	uint64_t note_key;
	size_t len;
	int count, failed;
	struct ndb_writer_msg out;

	if (!ndb_begin_rw_query(ndb, &txn)) {
		fprintf(stderr, "ndb_migrate_utf8_profile_names: ndb_begin_rw_query failed\n");
		return 0;
	}

	if ((rc = mdb_cursor_open(txn.mdb_txn, ndb->lmdb.dbs[NDB_DB_PROFILE], &cur))) {
		fprintf(stderr, "ndb_migrate_utf8_profile_names: mdb_cursor_open failed, error %d\n", rc);
		return 0;
	}

	count = 0;
	failed = 0;

	// loop through all profiles and write search indices
	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
		profile_root = v.mv_data;
		record = NdbProfileRecord_as_root(profile_root);
		note_key = NdbProfileRecord_note_key(record);
		note = ndb_get_note_by_key(&txn, note_key, &len);

		if (note == NULL) {
			fprintf(stderr, "ndb_migrate_utf8_profile_names: note lookup failed\n");
			return 0;
		}

		struct ndb_profile_record_builder *b = &out.profile.record;

		// reprocess profile
		if (!ndb_process_profile_note(note, b)) {
			failed++;
			continue;
		}

		// the writer needs to own this note, and its expected to free it
		copied_note = malloc(len);
		memcpy(copied_note, note, len);

		out.type = NDB_WRITER_PROFILE;
		out.profile.note.note = copied_note;
		out.profile.note.note_len = len;

		ndb_writer_queue_msg(&ndb->writer, &out);

		count++;
	}

	fprintf(stderr, "migrated %d profiles to fix utf8 profile names\n", count);

	if (failed != 0) {
		fprintf(stderr, "failed to migrate %d profiles to fix utf8 profile names\n", failed);
	}

	mdb_cursor_close(cur);

	ndb_end_query(&txn);

	return 1;
}

static struct ndb_migration MIGRATIONS[] = {
	{ .fn = ndb_migrate_user_search_indices },
	{ .fn = ndb_migrate_lower_user_search_indices },
	{ .fn = ndb_migrate_utf8_profile_names }
};


int ndb_end_query(struct ndb_txn *txn)
{
	// this works on read or write queries.
	return mdb_txn_commit(txn->mdb_txn) == 0;
}

int ndb_note_verify(void *ctx, unsigned char pubkey[32], unsigned char id[32],
		    unsigned char sig[64])
{
	secp256k1_xonly_pubkey xonly_pubkey;
	int ok;

	ok = secp256k1_xonly_pubkey_parse((secp256k1_context*)ctx, &xonly_pubkey,
					  pubkey) != 0;
	if (!ok) return 0;

	ok = secp256k1_schnorrsig_verify((secp256k1_context*)ctx, sig, id, 32,
					 &xonly_pubkey) > 0;
	if (!ok) return 0;

	return 1;
}

static int ndb_writer_queue_note(struct ndb_writer *writer,
				 struct ndb_note *note, size_t note_len)
{
	struct ndb_writer_msg msg;
	msg.type = NDB_WRITER_NOTE;

	msg.note.note = note;
	msg.note.note_len = note_len;

	return prot_queue_push(&writer->inbox, &msg);
}

static void ndb_writer_last_profile_fetch(struct ndb_txn *txn,
					  const unsigned char *pubkey,
					  uint64_t fetched_at)
{
	int rc;
	MDB_val key, val;

	key.mv_data = (unsigned char*)pubkey;
	key.mv_size = 32;
	val.mv_data = &fetched_at;
	val.mv_size = sizeof(fetched_at);

	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_LAST_FETCH],
			  &key, &val, 0)))
	{
		ndb_debug("write version to ndb_meta failed: %s\n",
				mdb_strerror(rc));
		return;
	}

	//fprintf(stderr, "writing version %" PRIu64 "\n", version);
}


// We just received a profile that we haven't processed yet, but it could
// be an older one! Make sure we only write last fetched profile if it's a new
// one
//
// To do this, we first check the latest profile in the database. If the
// created_date for this profile note is newer, then we write a
// last_profile_fetch record, otherwise we do not.
//
// WARNING: This function is only valid when called from the writer thread
static int ndb_maybe_write_last_profile_fetch(struct ndb_txn *txn,
					       struct ndb_note *note)
{
	size_t len;
	uint64_t profile_key, note_key;
	void *root;
	struct ndb_note *last_profile;
	NdbProfileRecord_table_t record;

	if ((root = ndb_get_profile_by_pubkey(txn, note->pubkey, &len, &profile_key))) {
		record = NdbProfileRecord_as_root(root);
		note_key = NdbProfileRecord_note_key(record);
		last_profile = ndb_get_note_by_key(txn, note_key, &len);
		if (last_profile == NULL) {
			return 0;
		}

		// found profile, let's see if it's newer than ours
		if (note->created_at > last_profile->created_at) {
			// this is a new profile note, record last fetched time
			ndb_writer_last_profile_fetch(txn, note->pubkey, time(NULL));
		}
	} else {
		// couldn't fetch profile. record last fetched time
		ndb_writer_last_profile_fetch(txn, note->pubkey, time(NULL));
	}

	return 1;
}

int ndb_write_last_profile_fetch(struct ndb *ndb, const unsigned char *pubkey,
				 uint64_t fetched_at)
{
	struct ndb_writer_msg msg;
	msg.type = NDB_WRITER_PROFILE_LAST_FETCH;
	memcpy(&msg.last_fetch.pubkey[0], pubkey, 32);
	msg.last_fetch.fetched_at = fetched_at;

	return ndb_writer_queue_msg(&ndb->writer, &msg);
}


// When doing cursor scans from greatest to lowest, this function positions the
// cursor at the first element before descending. MDB_SET_RANGE puts us right
// after the first element, so we have to go back one.
static int ndb_cursor_start(MDB_cursor *cur, MDB_val *k, MDB_val *v)
{
	// Position cursor at the next key greater than or equal to the
	// specified key
	if (mdb_cursor_get(cur, k, v, MDB_SET_RANGE)) {
		// Failed :(. It could be the last element?
		if (mdb_cursor_get(cur, k, v, MDB_LAST))
			return 0;
	} else {
		// if set range worked and our key exists, it should be
		// the one right before this one
		if (mdb_cursor_get(cur, k, v, MDB_PREV))
			return 0;
	}

	return 1;
}

// get some value based on a clustered id key
int ndb_get_tsid(struct ndb_txn *txn, enum ndb_dbs db, const unsigned char *id,
		 MDB_val *val)
{
	MDB_val k, v;
	MDB_cursor *cur;
	int success = 0, rc;
	struct ndb_tsid tsid;

	// position at the most recent
	ndb_tsid_high(&tsid, id);

	k.mv_data = &tsid;
	k.mv_size = sizeof(tsid);

	if ((rc = mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[db], &cur))) {
		ndb_debug("ndb_get_tsid: failed to open cursor: '%s'\n", mdb_strerror(rc));
		return 0;
	}

	if (!ndb_cursor_start(cur, &k, &v))
		goto cleanup;

	if (memcmp(k.mv_data, id, 32) == 0) {
		*val = v;
		success = 1;
	}

cleanup:
	mdb_cursor_close(cur);
	return success;
}

static void *ndb_lookup_by_key(struct ndb_txn *txn, uint64_t key,
			       enum ndb_dbs store, size_t *len)
{
	MDB_val k, v;

	k.mv_data = &key;
	k.mv_size = sizeof(key);

	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[store], &k, &v)) {
		ndb_debug("ndb_lookup_by_key: mdb_get note failed\n");
		return NULL;
	}

	if (len)
		*len = v.mv_size;

	return v.mv_data;
}

static void *ndb_lookup_tsid(struct ndb_txn *txn, enum ndb_dbs ind,
			     enum ndb_dbs store, const unsigned char *pk,
			     size_t *len, uint64_t *primkey)
{
	MDB_val k, v;
	void *res = NULL;
	if (len)
		*len = 0;

	if (!ndb_get_tsid(txn, ind, pk, &k)) {
		//ndb_debug("ndb_get_profile_by_pubkey: ndb_get_tsid failed\n");
		return 0;
	}

	if (primkey)
		*primkey = *(uint64_t*)k.mv_data;

	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[store], &k, &v)) {
		ndb_debug("ndb_get_profile_by_pubkey: mdb_get note failed\n");
		return 0;
	}

	res = v.mv_data;
	assert(((uint64_t)res % 4) == 0);
	if (len)
		*len = v.mv_size;
	return res;
}

void *ndb_get_profile_by_pubkey(struct ndb_txn *txn, const unsigned char *pk, size_t *len, uint64_t *key)
{
	return ndb_lookup_tsid(txn, NDB_DB_PROFILE_PK, NDB_DB_PROFILE, pk, len, key);
}

struct ndb_note *ndb_get_note_by_id(struct ndb_txn *txn, const unsigned char *id, size_t *len, uint64_t *key)
{
	return ndb_lookup_tsid(txn, NDB_DB_NOTE_ID, NDB_DB_NOTE, id, len, key);
}

static inline uint64_t ndb_get_indexkey_by_id(struct ndb_txn *txn,
					      enum ndb_dbs db,
					      const unsigned char *id)
{
	MDB_val k;

	if (!ndb_get_tsid(txn, db, id, &k))
		return 0;

	return *(uint32_t*)k.mv_data;
}

uint64_t ndb_get_notekey_by_id(struct ndb_txn *txn, const unsigned char *id)
{
	return ndb_get_indexkey_by_id(txn, NDB_DB_NOTE_ID, id);
}

uint64_t ndb_get_profilekey_by_pubkey(struct ndb_txn *txn, const unsigned char *id)
{
	return ndb_get_indexkey_by_id(txn, NDB_DB_PROFILE_PK, id);
}

struct ndb_note *ndb_get_note_by_key(struct ndb_txn *txn, uint64_t key, size_t *len)
{
	return ndb_lookup_by_key(txn, key, NDB_DB_NOTE, len);
}

void *ndb_get_profile_by_key(struct ndb_txn *txn, uint64_t key, size_t *len)
{
	return ndb_lookup_by_key(txn, key, NDB_DB_PROFILE, len);
}

uint64_t
ndb_read_last_profile_fetch(struct ndb_txn *txn, const unsigned char *pubkey)
{
	MDB_val k, v;

	k.mv_data = (unsigned char*)pubkey;
	k.mv_size = 32;

	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_PROFILE_LAST_FETCH], &k, &v)) {
		//ndb_debug("ndb_read_last_profile_fetch: mdb_get note failed\n");
		return 0;
	}

	return *((uint64_t*)v.mv_data);
}


static int ndb_has_note(struct ndb_txn *txn, const unsigned char *id)
{
	MDB_val val;

	if (!ndb_get_tsid(txn, NDB_DB_NOTE_ID, id, &val))
		return 0;

	return 1;
}

static void ndb_txn_from_mdb(struct ndb_txn *txn, struct ndb_lmdb *lmdb,
			     MDB_txn *mdb_txn)
{
	txn->lmdb = lmdb;
	txn->mdb_txn = mdb_txn;
}

static enum ndb_idres ndb_ingester_json_controller(void *data, const char *hexid)
{
	unsigned char id[32];
	struct ndb_ingest_controller *c = data;
	struct ndb_txn txn;

	hex_decode(hexid, 64, id, sizeof(id));

	// let's see if we already have it

	ndb_txn_from_mdb(&txn, c->lmdb, c->read_txn);
	if (!ndb_has_note(&txn, id))
		return NDB_IDRES_CONT;

	return NDB_IDRES_STOP;
}

static int ndbprofile_parse_json(flatcc_builder_t *B,
        const char *buf, size_t bufsiz, int flags, NdbProfile_ref_t *profile)
{
	flatcc_json_parser_t parser, *ctx = &parser;
	flatcc_json_parser_init(ctx, B, buf, buf + bufsiz, flags);

	if (flatcc_builder_start_buffer(B, 0, 0, 0))
		return 0;

	NdbProfile_parse_json_table(ctx, buf, buf + bufsiz, profile);
	if (ctx->error)
		return 0;

	if (!flatcc_builder_end_buffer(B, *profile))
		return 0;

	ctx->end_loc = buf;


	return 1;
}

void ndb_profile_record_builder_init(struct ndb_profile_record_builder *b)
{
	b->builder = malloc(sizeof(*b->builder));
	b->flatbuf = NULL;
}

void ndb_profile_record_builder_free(struct ndb_profile_record_builder *b)
{
	if (b->builder)
		free(b->builder);
	if (b->flatbuf)
		free(b->flatbuf);

	b->builder = NULL;
	b->flatbuf = NULL;
}

int ndb_process_profile_note(struct ndb_note *note,
			     struct ndb_profile_record_builder *profile)
{
	int res;

	NdbProfile_ref_t profile_table;
	flatcc_builder_t *builder;

	ndb_profile_record_builder_init(profile);
	builder = profile->builder;
	flatcc_builder_init(builder);

	NdbProfileRecord_start_as_root(builder);

	//printf("parsing profile '%.*s'\n", note->content_length, ndb_note_content(note));
	if (!(res = ndbprofile_parse_json(builder, ndb_note_content(note),
					  note->content_length,
					  flatcc_json_parser_f_skip_unknown,
					  &profile_table)))
	{
		ndb_debug("profile_parse_json failed %d '%.*s'\n", res,
			  note->content_length, ndb_note_content(note));
		ndb_profile_record_builder_free(profile);
		return 0;
	}

	uint64_t received_at = time(NULL);
	const char *lnurl = "fixme";

	NdbProfileRecord_profile_add(builder, profile_table);
	NdbProfileRecord_received_at_add(builder, received_at);

	flatcc_builder_ref_t lnurl_off;
	lnurl_off = flatcc_builder_create_string_str(builder, lnurl);

	NdbProfileRecord_lnurl_add(builder, lnurl_off);

	//*profile = flatcc_builder_finalize_aligned_buffer(builder, profile_len);
	return 1;
}

static int ndb_ingester_queue_event(struct ndb_ingester *ingester,
				    char *json, unsigned len, unsigned client)
{
	struct ndb_ingester_msg msg;
	msg.type = NDB_INGEST_EVENT;

	msg.event.json = json;
	msg.event.len = len;
	msg.event.client = client;

	return threadpool_dispatch(&ingester->tp, &msg);
}


static int ndb_ingest_event(struct ndb_ingester *ingester, const char *json,
			    int len, unsigned client)
{
	// Since we need to return as soon as possible, and we're not
	// making any assumptions about the lifetime of the string, we
	// definitely need to copy the json here. In the future once we
	// have our thread that manages a websocket connection, we can
	// avoid the copy and just use the buffer we get from that
	// thread.
	char *json_copy = strdupn(json, len);
	if (json_copy == NULL)
		return 0;

	return ndb_ingester_queue_event(ingester, json_copy, len, client);
}


static int ndb_ingester_process_note(secp256k1_context *ctx,
				     struct ndb_note *note,
				     size_t note_size,
				     struct ndb_writer_msg *out,
				     struct ndb_ingester *ingester)
{
	enum ndb_ingest_filter_action action;
	action = NDB_INGEST_ACCEPT;

	if (ingester->filter)
		action = ingester->filter(ingester->filter_context, note);

	if (action == NDB_INGEST_REJECT)
		return 0;

	// some special situations we might want to skip sig validation,
	// like during large imports
	if (action == NDB_INGEST_SKIP_VALIDATION || (ingester->flags & NDB_FLAG_SKIP_NOTE_VERIFY)) {
		// if we're skipping validation we don't need to verify
	} else {
		// verify! If it's an invalid note we don't need to
		// bother writing it to the database
		if (!ndb_note_verify(ctx, note->pubkey, note->id, note->sig)) {
			ndb_debug("signature verification failed\n");
			return 0;
		}
	}

	// we didn't find anything. let's send it
	// to the writer thread
	note = realloc(note, note_size);
	assert(((uint64_t)note % 4) == 0);

	if (note->kind == 0) {
		struct ndb_profile_record_builder *b =
			&out->profile.record;

		ndb_process_profile_note(note, b);

		out->type = NDB_WRITER_PROFILE;
		out->profile.note.note = note;
		out->profile.note.note_len = note_size;
		return 1;
	} else if (note->kind == 6) {
		// process the repost if we have a repost event
		ndb_debug("processing kind 6 repost\n");
		ndb_ingest_event(ingester, ndb_note_content(note),
					   ndb_note_content_length(note), 0);
	}

	out->type = NDB_WRITER_NOTE;
	out->note.note = note;
	out->note.note_len = note_size;

	return 1;
}


static int ndb_ingester_process_event(secp256k1_context *ctx,
				      struct ndb_ingester *ingester,
				      struct ndb_ingester_event *ev,
				      struct ndb_writer_msg *out,
				      MDB_txn *read_txn
				      )
{
	struct ndb_tce tce;
	struct ndb_fce fce;
	struct ndb_note *note;
	struct ndb_ingest_controller controller;
	struct ndb_id_cb cb;
	void *buf;
	int ok;
	size_t bufsize, note_size;

	ok = 0;

	// we will use this to check if we already have it in the DB during
	// ID parsing
	controller.read_txn = read_txn;
	controller.lmdb = ingester->lmdb;
	cb.fn = ndb_ingester_json_controller;
	cb.data = &controller;

	// since we're going to be passing this allocated note to a different
	// thread, we can't use thread-local buffers. just allocate a block
        bufsize = max(ev->len * 8.0, 4096);
	buf = malloc(bufsize);
	if (!buf) {
		ndb_debug("couldn't malloc buf\n");
		return 0;
	}

	note_size =
		ev->client ?
		ndb_client_event_from_json(ev->json, ev->len, &fce, buf, bufsize, &cb) :
		ndb_ws_event_from_json(ev->json, ev->len, &tce, buf, bufsize, &cb);

	if ((int)note_size == -42) {
		// we already have this!
		//ndb_debug("already have id??\n");
		goto cleanup;
	} else if (note_size == 0) {
		ndb_debug("failed to parse '%.*s'\n", ev->len, ev->json);
		goto cleanup;
	}

	//ndb_debug("parsed evtype:%d '%.*s'\n", tce.evtype, ev->len, ev->json);

	if (ev->client) {
		switch (fce.evtype) {
		case NDB_FCE_EVENT:
			note = fce.event.note;
			if (note != buf) {
				ndb_debug("note buffer not equal to malloc'd buffer\n");
				goto cleanup;
			}

			if (!ndb_ingester_process_note(ctx, note, note_size,
						       out, ingester)) {
				ndb_debug("failed to process note\n");
				goto cleanup;
			} else {
				// we're done with the original json, free it
				free(ev->json);
				return 1;
			}
		}
	} else {
		switch (tce.evtype) {
		case NDB_TCE_AUTH:   goto cleanup;
		case NDB_TCE_NOTICE: goto cleanup;
		case NDB_TCE_EOSE:   goto cleanup;
		case NDB_TCE_OK:     goto cleanup;
		case NDB_TCE_EVENT:
			note = tce.event.note;
			if (note != buf) {
				ndb_debug("note buffer not equal to malloc'd buffer\n");
				goto cleanup;
			}

			if (!ndb_ingester_process_note(ctx, note, note_size,
						       out, ingester)) {
				ndb_debug("failed to process note\n");
				goto cleanup;
			} else {
				// we're done with the original json, free it
				free(ev->json);
				return 1;
			}
		}
	}


cleanup:
	free(ev->json);
	free(buf);

	return ok;
}

static uint64_t ndb_get_last_key(MDB_txn *txn, MDB_dbi db)
{
	MDB_cursor *mc;
	MDB_val key, val;

	if (mdb_cursor_open(txn, db, &mc))
		return 0;

	if (mdb_cursor_get(mc, &key, &val, MDB_LAST)) {
		mdb_cursor_close(mc);
		return 0;
	}

	mdb_cursor_close(mc);

	assert(key.mv_size == 8);
        return *((uint64_t*)key.mv_data);
}

//
// make a search key meant for user queries without any other note info
static void ndb_make_search_key_low(struct ndb_search_key *key, const char *search)
{
	memset(key->id, 0, sizeof(key->id));
	key->timestamp = 0;
	lowercase_strncpy(key->search, search, sizeof(key->search) - 1);
	key->search[sizeof(key->search) - 1] = '\0';
}

int ndb_search_profile(struct ndb_txn *txn, struct ndb_search *search, const char *query)
{
	int rc;
	struct ndb_search_key s;
	MDB_val k, v;
	search->cursor = NULL;

	MDB_cursor **cursor = (MDB_cursor **)&search->cursor;

	ndb_make_search_key_low(&s, query);

	k.mv_data = &s;
	k.mv_size = sizeof(s);

	if ((rc = mdb_cursor_open(txn->mdb_txn,
				  txn->lmdb->dbs[NDB_DB_PROFILE_SEARCH],
				  cursor))) {
		printf("search_profile: cursor opened failed: %s\n",
				mdb_strerror(rc));
		return 0;
	}

	// Position cursor at the next key greater than or equal to the specified key
	if (mdb_cursor_get(search->cursor, &k, &v, MDB_SET_RANGE)) {
		printf("search_profile: cursor get failed\n");
		goto cleanup;
	} else {
		search->key = k.mv_data;
		assert(v.mv_size == 8);
		search->profile_key = *((uint64_t*)v.mv_data);
		return 1;
	}

cleanup:
	mdb_cursor_close(search->cursor);
	search->cursor = NULL;
	return 0;
}

void ndb_search_profile_end(struct ndb_search *search)
{
	if (search->cursor)
		mdb_cursor_close(search->cursor);
}

int ndb_search_profile_next(struct ndb_search *search)
{
	int rc;
	MDB_val k, v;
	unsigned char *init_id;

	init_id = search->key->id;
	k.mv_data = search->key;
	k.mv_size = sizeof(*search->key);

retry:
	if ((rc = mdb_cursor_get(search->cursor, &k, &v, MDB_NEXT))) {
		ndb_debug("ndb_search_profile_next: %s\n",
				mdb_strerror(rc));
		return 0;
	} else {
		search->key = k.mv_data;
		assert(v.mv_size == 8);
		search->profile_key = *((uint64_t*)v.mv_data);

		// skip duplicate pubkeys
		if (!memcmp(init_id, search->key->id, 32))
			goto retry;
	}

	return 1;
}

static int ndb_search_key_cmp(const MDB_val *a, const MDB_val *b)
{
	int cmp;
	struct ndb_search_key *ska, *skb;

	ska = a->mv_data;
	skb = b->mv_data;

	MDB_val a2 = *a;
	MDB_val b2 = *b;

	a2.mv_data = ska->search;
	a2.mv_size = sizeof(ska->search) + sizeof(ska->id);

	cmp = mdb_cmp_memn(&a2, &b2);
	if (cmp) return cmp;

	if (ska->timestamp < skb->timestamp)
		return -1;
	else if (ska->timestamp > skb->timestamp)
		return 1;

	return 0;
}

static int ndb_write_profile_pk_index(struct ndb_txn *txn, struct ndb_note *note, uint64_t profile_key)

{
	MDB_val key, val;
	int rc;
	struct ndb_tsid tsid;
	MDB_dbi pk_db;

	pk_db = txn->lmdb->dbs[NDB_DB_PROFILE_PK];

	// write profile_pk + created_at index
	ndb_tsid_init(&tsid, note->pubkey, note->created_at);

	key.mv_data = &tsid;
	key.mv_size = sizeof(tsid);
	val.mv_data = &profile_key;
	val.mv_size = sizeof(profile_key);

	if ((rc = mdb_put(txn->mdb_txn, pk_db, &key, &val, 0))) {
		ndb_debug("write profile_pk(%" PRIu64 ") to db failed: %s\n",
				profile_key, mdb_strerror(rc));
		return 0;
	}

	return 1;
}

static int ndb_write_profile(struct ndb_txn *txn,
			     struct ndb_writer_profile *profile,
			     uint64_t note_key)
{
	uint64_t profile_key;
	struct ndb_note *note;
	void *flatbuf;
	size_t flatbuf_len;
	int rc;

	MDB_val key, val;
	MDB_dbi profile_db;

	note = profile->note.note;

	// add note_key to profile record
	NdbProfileRecord_note_key_add(profile->record.builder, note_key);
	NdbProfileRecord_end_as_root(profile->record.builder);

	flatbuf = profile->record.flatbuf =
		flatcc_builder_finalize_aligned_buffer(profile->record.builder, &flatbuf_len);

	assert(((uint64_t)flatbuf % 8) == 0);

	// TODO: this may not be safe!?
	flatbuf_len = (flatbuf_len + 7) & ~7;

	//assert(NdbProfileRecord_verify_as_root(flatbuf, flatbuf_len) == 0);

	// get dbs
	profile_db = txn->lmdb->dbs[NDB_DB_PROFILE];

	// get new key
	profile_key = ndb_get_last_key(txn->mdb_txn, profile_db) + 1;

	// write profile to profile store
	key.mv_data = &profile_key;
	key.mv_size = sizeof(profile_key);
	val.mv_data = flatbuf;
	val.mv_size = flatbuf_len;

	if ((rc = mdb_put(txn->mdb_txn, profile_db, &key, &val, 0))) {
		ndb_debug("write profile to db failed: %s\n", mdb_strerror(rc));
		return 0;
	}

	// write last fetched record
	if (!ndb_maybe_write_last_profile_fetch(txn, note)) {
		ndb_debug("failed to write last profile fetched record\n");
	}

	// write profile pubkey index
	if (!ndb_write_profile_pk_index(txn, note, profile_key)) {
		ndb_debug("failed to write profile pubkey index\n");
		return 0;
	}

	// write name, display_name profile search indices
	if (!ndb_write_profile_search_indices(txn, note, profile_key,
					      flatbuf)) {
		ndb_debug("failed to write profile search indices\n");
		return 0;
	}

	return 1;
}

// find the last id tag in a note (e, p, etc)
static unsigned char *ndb_note_last_id_tag(struct ndb_note *note, char type)
{
	unsigned char *last = NULL;
	struct ndb_iterator iter;
	struct ndb_str str;

	// get the liked event id (last id)
	ndb_tags_iterate_start(note, &iter);

	while (ndb_tags_iterate_next(&iter)) {
		if (iter.tag->count < 2)
			continue;

		str = ndb_tag_str(note, iter.tag, 0);

		// assign liked to the last e tag
		if (str.flag == NDB_PACKED_STR && str.str[0] == type) {
			str = ndb_tag_str(note, iter.tag, 1);
			if (str.flag == NDB_PACKED_ID)
				last = str.id;
		}
	}

	return last;
}

void *ndb_get_note_meta(struct ndb_txn *txn, const unsigned char *id, size_t *len)
{
	MDB_val k, v;

	k.mv_data = (unsigned char*)id;
	k.mv_size = 32;

	if (mdb_get(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_META], &k, &v)) {
		//ndb_debug("ndb_get_note_meta: mdb_get note failed\n");
		return NULL;
	}

	if (len)
		*len = v.mv_size;

	return v.mv_data;
}

// When receiving a reaction note, look for the liked id and increase the
// reaction counter in the note metadata database
static int ndb_write_reaction_stats(struct ndb_txn *txn, struct ndb_note *note)
{
	size_t len;
	void *root;
	int reactions, rc;
	MDB_val key, val;
	NdbEventMeta_table_t meta;
	unsigned char *liked = ndb_note_last_id_tag(note, 'e');

	if (liked == NULL)
		return 0;

	root = ndb_get_note_meta(txn, liked, &len);

	flatcc_builder_t builder;
	flatcc_builder_init(&builder);
	NdbEventMeta_start_as_root(&builder);

	// no meta record, let's make one
	if (root == NULL) {
		NdbEventMeta_reactions_add(&builder, 1);
	} else {
		// clone existing and add to it
		meta = NdbEventMeta_as_root(root);

		reactions = NdbEventMeta_reactions_get(meta);
		NdbEventMeta_clone(&builder, meta);
		NdbEventMeta_reactions_add(&builder, reactions + 1);
	}

	NdbProfileRecord_end_as_root(&builder);
	root = flatcc_builder_finalize_aligned_buffer(&builder, &len);
	assert(((uint64_t)root % 8) == 0);

	if (root == NULL) {
		ndb_debug("failed to create note metadata record\n");
		return 0;
	}

	// metadata is keyed on id because we want to collect stats regardless
	// if we have the note yet or not
	key.mv_data = liked;
	key.mv_size = 32;

	val.mv_data = root;
	val.mv_size = len;

	// write the new meta record
	//ndb_debug("writing stats record for ");
	//print_hex(liked, 32);
	//ndb_debug("\n");

	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_META], &key, &val, 0))) {
		ndb_debug("write reaction stats to db failed: %s\n", mdb_strerror(rc));
		return 0;
	}

	free(root);

	return 1;
}


static int ndb_write_note_id_index(struct ndb_txn *txn, struct ndb_note *note,
				   uint64_t note_key)

{
	struct ndb_tsid tsid;
	int rc;
	MDB_val key, val;
	MDB_dbi id_db;

	ndb_tsid_init(&tsid, note->id, note->created_at);

	key.mv_data = &tsid;
	key.mv_size = sizeof(tsid);
	val.mv_data = &note_key;
	val.mv_size = sizeof(note_key);

	id_db = txn->lmdb->dbs[NDB_DB_NOTE_ID];

	if ((rc = mdb_put(txn->mdb_txn, id_db, &key, &val, 0))) {
		ndb_debug("write note id index to db failed: %s\n",
				mdb_strerror(rc));
		return 0;
	}

	return 1;
}

static int ndb_filter_group_add_filters(struct ndb_filter_group *group,
					struct ndb_filter *filters,
					int num_filters)
{
	int i;

	for (i = 0; i < num_filters; i++) {
		if (!ndb_filter_group_add(group, &filters[i]))
			return 0;
	}

	return 1;
}


static struct ndb_filter_elements *
ndb_filter_find_elements(struct ndb_filter *filter, enum ndb_filter_fieldtype typ)
{
	int i;
	struct ndb_filter_elements *els;

	for (i = 0; i < filter->num_elements; i++) {
		els = ndb_filter_get_elements(filter, i);
		assert(els);
		if (els->field.type == typ) {
			return els;
		}
	}

	return NULL;
}

int ndb_filter_is_subset_of(const struct ndb_filter *a, const struct ndb_filter *b)
{
	int i;
	struct ndb_filter_elements *b_field, *a_field;

        // Everything is always a subset of {}
	if (b->num_elements == 0)
		return 1;

        // We can't be a subset if the number of elements in the other
        // filter is larger then the number of elements we have.
	if (b->num_elements > a->num_elements)
		return 0;

        // If our filter count matches, we can only be a subset if we are
        // equal
	if (b->num_elements == a->num_elements)
		return ndb_filter_eq(a, b);

        // If our element count is larger than the other filter, then we
        // must see if every element in the other filter exists in ours. If
        // so, then we are a subset of the other.
        //
        // eg: B={k:1, a:b} <- A={t:x, k:1, a:b}
        //
        // A is a subset of B because `k:1` and `a:b` both exist in A

	for (i = 0; i < b->num_elements; i++) {
		b_field = ndb_filter_get_elements((struct ndb_filter*)b, i);
		a_field = ndb_filter_find_elements((struct ndb_filter*)a,
						   b_field->field.type);

		if (a_field == NULL)
			return 0;

		if (!ndb_filter_field_eq((struct ndb_filter*)a, a_field,
					 (struct ndb_filter*)b, b_field))
			return 0;
	}

	return 1;
}

int ndb_filter_eq(const struct ndb_filter *a, const struct ndb_filter *b)
{
	int i;
	struct ndb_filter_elements *a_els, *b_els;

	if (a->num_elements != b->num_elements)
		return 0;

	for (i = 0; i < a->num_elements; i++) {
		a_els = ndb_filter_get_elements((struct ndb_filter*)a, i);
		b_els = ndb_filter_find_elements((struct ndb_filter *)b,
						 a_els->field.type);

		if (b_els == NULL)
			return 0;

		if (!ndb_filter_field_eq((struct ndb_filter*)a, a_els,
					 (struct ndb_filter*)b, b_els))
			return 0;
	}

	return 1;
}


static uint64_t *
ndb_filter_get_elem(struct ndb_filter *filter, enum ndb_filter_fieldtype typ)
{
	struct ndb_filter_elements *els;
	if ((els = ndb_filter_find_elements(filter, typ)))
		return &els->elements[0];
	return NULL;
}

static uint64_t *ndb_filter_get_int(struct ndb_filter *filter,
				    enum ndb_filter_fieldtype typ)
{
	uint64_t *el;
	if (NULL == (el = ndb_filter_get_elem(filter, typ)))
		return NULL;
	return el;
}

static inline int push_query_result(struct ndb_query_results *results,
				    struct ndb_query_result *result)
{
	return cursor_push(&results->cur, (unsigned char*)result, sizeof(*result));
}

static int compare_query_results(const void *pa, const void *pb)
{
	struct ndb_query_result *a, *b;

	a = (struct ndb_query_result *)pa;
	b = (struct ndb_query_result *)pb;

	if (a->note->created_at == b->note->created_at) {
		return 0;
	} else if (a->note->created_at > b->note->created_at) {
		return -1;
	} else {
		return 1;
	}
}

static void ndb_query_result_init(struct ndb_query_result *res,
				  struct ndb_note *note,
				  uint64_t note_size,
				  uint64_t note_id)
{
	*res = (struct ndb_query_result){
		.note_id = note_id,
		.note_size = note_size,
		.note = note,
	};
}

static int query_is_full(struct ndb_query_results *results, int limit)
{
	if (results->cur.p >= results->cur.end)
		return 1;

	return cursor_count(&results->cur, sizeof(struct ndb_query_result)) >= limit;
}

static int ndb_query_plan_execute_ids(struct ndb_txn *txn,
				      struct ndb_filter *filter,
				      struct ndb_query_results *results,
				      int limit
				      )
{
	MDB_cursor *cur;
	MDB_dbi db;
	MDB_val k, v;
	int matched, rc, i;
	struct ndb_filter_elements *ids;
	struct ndb_note *note;
	struct ndb_query_result res;
	struct ndb_tsid tsid, *ptsid;
	uint64_t note_id, until, *pint;
	size_t note_size;
	unsigned char *id;

	matched = 0;
	until = UINT64_MAX;

	if (!(ids = ndb_filter_find_elements(filter, NDB_FILTER_IDS)))
		return 0;

	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
		until = *pint;

	db = txn->lmdb->dbs[NDB_DB_NOTE_ID];
	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
		return 0;

	// for each id in our ids filter, find in the db
	for (i = 0; i < ids->count; i++) {
		if (query_is_full(results, limit))
			break;

		id = ndb_filter_get_id_element(filter, ids, i);
		ndb_tsid_init(&tsid, (unsigned char *)id, until);

		k.mv_data = &tsid;
		k.mv_size = sizeof(tsid);

		if (!ndb_cursor_start(cur, &k, &v))
			continue;

		ptsid = (struct ndb_tsid *)k.mv_data;
		note_id = *(uint64_t*)v.mv_data;

		if (memcmp(id, ptsid->id, 32) == 0)
			matched |= 1 << NDB_FILTER_AUTHORS;
		else
			continue;

		// get the note because we need it to match against the filter
		if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
			continue;

		// Sure this particular lookup matched the index query, but
		// does it match the entire filter? Check! We also pass in
		// things we've already matched via the filter so we don't have
		// to check again. This can be pretty important for filters
		// with a large number of entries.
		if (!ndb_filter_matches_with(filter, note, matched))
			continue;

		ndb_query_result_init(&res, note, note_size, note_id);
		if (!push_query_result(results, &res))
			break;
	}

	mdb_cursor_close(cur);
	return 1;
}

//
// encode a tag index key
//
// consists of:
//
//   u8   tag
//   u8   tag_val_len
//   [u8] tag_val_bytes
//   u64  created_at
//
static int ndb_encode_tag_key(unsigned char *buf, int buf_size,
			      char tag, const unsigned char *val,
			      unsigned char val_len,
			      uint64_t timestamp)
{
	struct cursor writer;
	int ok;

	// quick exit for obvious case where it will be too big. There can be
	// values of val_len that still fail, but we just let the writer handle
	// those failure cases
	if (val_len >= buf_size)
		return 0;

	make_cursor(buf, buf + buf_size, &writer);

	ok =
		cursor_push_byte(&writer, tag) &&
		cursor_push(&writer, (unsigned char*)val, val_len) &&
		cursor_push(&writer, (unsigned char*)&timestamp, sizeof(timestamp));

	if (!ok)
		return 0;

	return writer.p - writer.start;
}

static int ndb_query_plan_execute_created_at(struct ndb_txn *txn,
					     struct ndb_filter *filter,
					     struct ndb_query_results *results,
					     int limit)
{
	MDB_dbi db;
	MDB_val k, v;
	MDB_cursor *cur;
	int rc;
	struct ndb_note *note;
	struct ndb_tsid key, *pkey;
	uint64_t *pint, until, since, note_id;
	size_t note_size;
	struct ndb_query_result res;
	unsigned char high_key[32] = {0xFF};

	db = txn->lmdb->dbs[NDB_DB_NOTE_ID];

	until = UINT64_MAX;
	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
		until = *pint;

	since = 0;
	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_SINCE)))
		since = *pint;

	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
		return 0;

	// if we have until, start there, otherwise just use max
	ndb_tsid_init(&key, high_key, until);
	k.mv_data = &key;
	k.mv_size = sizeof(key);

	if (!ndb_cursor_start(cur, &k, &v))
		return 1;

	while (!query_is_full(results, limit)) {
		pkey = (struct ndb_tsid *)k.mv_data;
		note_id = *(uint64_t*)v.mv_data;
		assert(v.mv_size == 8);

		// TODO(perf): if we are only looking for IDs and have no other
		// condition, then we can use the ID in the index without
		// looking up the note. For now we always look up the note
		if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
			goto next;

		// does this entry match our filter?
		if (!ndb_filter_matches_with(filter, note, 0))
			goto next;

		// don't continue the scan if we're below `since`
		if (pkey->timestamp < since)
			break;

		ndb_query_result_init(&res, note, (uint64_t)note_size, note_id);
		if (!push_query_result(results, &res))
			break;
next:
		if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
			break;
	}

	mdb_cursor_close(cur);
	return 1;
}

static int ndb_query_plan_execute_tags(struct ndb_txn *txn,
				       struct ndb_filter *filter,
				       struct ndb_query_results *results,
				       int limit)
{
	MDB_cursor *cur;
	MDB_dbi db;
	MDB_val k, v;
	int len, taglen, rc, i;
	uint64_t *pint, until, note_id;
	size_t note_size;
	unsigned char key_buffer[255];
	struct ndb_note *note;
	struct ndb_filter_elements *tags;
	unsigned char *tag;
	struct ndb_query_result res;

	db = txn->lmdb->dbs[NDB_DB_NOTE_TAGS];

	if (!(tags = ndb_filter_find_elements(filter, NDB_FILTER_TAGS)))
		return 0;

	until = UINT64_MAX;
	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
		until = *pint;

	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
		return 0;

	for (i = 0; i < tags->count; i++) {
		tag = ndb_filter_get_id_element(filter, tags, i);

		taglen = tags->field.elem_type == NDB_ELEMENT_ID
		       ? 32 : strlen((const char*)tag);

		if (!(len = ndb_encode_tag_key(key_buffer, sizeof(key_buffer),
					       tags->field.tag, tag, taglen,
					       until)))
			return 0;

		k.mv_data = key_buffer;
		k.mv_size = len;

		if (!ndb_cursor_start(cur, &k, &v))
			continue;

		// for each id in our ids filter, find in the db
		while (!query_is_full(results, limit)) {
			// check if tag value matches, bail if not
			if (((unsigned char *)k.mv_data)[0] != tags->field.tag)
				break;

			// check if tag value matches, bail if not
			if (taglen != k.mv_size - 9)
				break;

			if (memcmp((unsigned char *)k.mv_data+1, tag, k.mv_size-9))
				break;

			note_id = *(uint64_t*)v.mv_data;

			if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
				goto next;

			if (!ndb_filter_matches_with(filter, note, 1 << NDB_FILTER_TAGS))
				goto next;

			ndb_query_result_init(&res, note, note_size, note_id);
			if (!push_query_result(results, &res))
				break;

next:
			if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
				break;
		}
	}

	mdb_cursor_close(cur);
	return 1;
}

static int ndb_query_plan_execute_kinds(struct ndb_txn *txn,
					struct ndb_filter *filter,
					struct ndb_query_results *results,
					int limit)
{
	MDB_cursor *cur;
	MDB_dbi db;
	MDB_val k, v;
	struct ndb_note *note;
	struct ndb_u64_ts tsid, *ptsid;
	struct ndb_filter_elements *kinds;
	struct ndb_query_result res;
	uint64_t kind, note_id, until, *pint;
	size_t note_size;
	int i, rc;

	// we should have kinds in a kinds filter!
	if (!(kinds = ndb_filter_find_elements(filter, NDB_FILTER_KINDS)))
		return 0;

	until = UINT64_MAX;
	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_UNTIL)))
		until = *pint;

	db = txn->lmdb->dbs[NDB_DB_NOTE_KIND];

	if ((rc = mdb_cursor_open(txn->mdb_txn, db, &cur)))
		return 0;

	for (i = 0; i < kinds->count; i++) {
		if (query_is_full(results, limit))
			break;

		kind = kinds->elements[i];
		ndb_debug("kind %" PRIu64 "\n", kind);
		ndb_u64_ts_init(&tsid, kind, until);

		k.mv_data = &tsid;
		k.mv_size = sizeof(tsid);

		if (!ndb_cursor_start(cur, &k, &v))
			continue;

		// for each id in our ids filter, find in the db
		while (!query_is_full(results, limit)) {
			ptsid = (struct ndb_u64_ts *)k.mv_data;
			if (ptsid->u64 != kind)
				break;

			note_id = *(uint64_t*)v.mv_data;
			if (!(note = ndb_get_note_by_key(txn, note_id, &note_size)))
				goto next;

			if (!ndb_filter_matches_with(filter, note, 1 << NDB_FILTER_KINDS))
				goto next;

			ndb_query_result_init(&res, note, note_size, note_id);
			if (!push_query_result(results, &res))
				break;

next:
			if (mdb_cursor_get(cur, &k, &v, MDB_PREV))
				break;
		}
	}

	mdb_cursor_close(cur);
	return 1;
}

static enum ndb_query_plan ndb_filter_plan(struct ndb_filter *filter)
{
	struct ndb_filter_elements *ids, *kinds, *authors, *tags;

	ids = ndb_filter_find_elements(filter, NDB_FILTER_IDS);
	kinds = ndb_filter_find_elements(filter, NDB_FILTER_KINDS);
	authors = ndb_filter_find_elements(filter, NDB_FILTER_AUTHORS);
	tags = ndb_filter_find_elements(filter, NDB_FILTER_TAGS);

	// this is rougly similar to the heuristic in strfry's dbscan
	if (ids) {
		return NDB_PLAN_IDS;
	} else if (authors && authors->count <= 5) {
		// TODO: actually implment author plan and use it
		//return NDB_PLAN_AUTHORS;
		return NDB_PLAN_CREATED;
	} else if (tags && tags->count <= 5) {
		return NDB_PLAN_TAGS;
	} else if (kinds) {
		return NDB_PLAN_KINDS;
	}

	return NDB_PLAN_CREATED;
}

static const char *ndb_query_plan_name(int plan_id)
{
	switch (plan_id) {
		case NDB_PLAN_IDS:     return "ids";
		case NDB_PLAN_KINDS:   return "kinds";
		case NDB_PLAN_TAGS:    return "tags";
		case NDB_PLAN_CREATED: return "created";
		case NDB_PLAN_AUTHORS: return "authors";
	}

	return "unknown";
}

static int ndb_query_filter(struct ndb_txn *txn, struct ndb_filter *filter,
			    struct ndb_query_result *res, int capacity,
			    int *results_out)
{
	struct ndb_query_results results;
	uint64_t limit, *pint;
	enum ndb_query_plan plan;
	limit = capacity;

	if ((pint = ndb_filter_get_int(filter, NDB_FILTER_LIMIT)))
		limit = *pint;

	limit = min(capacity, limit);
	make_cursor((unsigned char *)res,
		    ((unsigned char *)res) + limit * sizeof(*res),
		    &results.cur);

	plan = ndb_filter_plan(filter);
	ndb_debug("using query plan '%s'\n", ndb_query_plan_name(plan));
	switch (plan) {
	// We have a list of ids, just open a cursor and jump to each once
	case NDB_PLAN_IDS:
		if (!ndb_query_plan_execute_ids(txn, filter, &results, limit))
			return 0;
		break;

	// We have just kinds, just scan the kind index
	case NDB_PLAN_KINDS:
		if (!ndb_query_plan_execute_kinds(txn, filter, &results, limit))
			return 0;
		break;

	case NDB_PLAN_TAGS:
		if (!ndb_query_plan_execute_tags(txn, filter, &results, limit))
			return 0;
		break;
	case NDB_PLAN_CREATED:
		if (!ndb_query_plan_execute_created_at(txn, filter, &results, limit))
			return 0;
		break;
	case NDB_PLAN_AUTHORS:
		// TODO: finish authors query plan
		return 0;
	}

	*results_out = cursor_count(&results.cur, sizeof(*res));
	return 1;
}

int ndb_query(struct ndb_txn *txn, struct ndb_filter *filters, int num_filters,
	      struct ndb_query_result *results, int result_capacity, int *count)
{
	int i, out;
	struct ndb_query_result *p = results;

	out = 0;
	*count = 0;

	for (i = 0; i < num_filters; i++) {
		if (!ndb_query_filter(txn, &filters[i], p,
				      result_capacity, &out)) {
			return 0;
		}

		*count += out;
		p += out;
		result_capacity -= out;
		if (result_capacity <= 0)
			break;
	}

	// sort results
	qsort(results, *count, sizeof(*results), compare_query_results);
	return 1;
}

static int ndb_write_note_tag_index(struct ndb_txn *txn, struct ndb_note *note,
				    uint64_t note_key)
{
	unsigned char key_buffer[255];
	struct ndb_iterator iter;
	struct ndb_str tkey, tval;
	char tchar;
	int len, rc;
	MDB_val key, val;
	MDB_dbi tags_db;

	tags_db = txn->lmdb->dbs[NDB_DB_NOTE_TAGS];

	ndb_tags_iterate_start(note, &iter);

	while (ndb_tags_iterate_next(&iter)) {
		if (iter.tag->count < 2)
			continue;

		tkey = ndb_tag_str(note, iter.tag, 0);

		// we only write indices for 1-char tags.
		tchar = tkey.str[0];
		if (tchar == 0 || tkey.str[1] != 0)
			continue;

		tval = ndb_tag_str(note, iter.tag, 1);
		len = ndb_str_len(&tval);

		if (!(len = ndb_encode_tag_key(key_buffer, sizeof(key_buffer),
					       tchar, tval.id, (unsigned char)len,
					       ndb_note_created_at(note)))) {
			// this will fail when we try to encode a key that is
			// too big
			continue;
		}

		//ndb_debug("writing tag '%c':'data:%d' to index\n", tchar, len);

		key.mv_data = key_buffer;
		key.mv_size = len;

		val.mv_data = &note_key;
		val.mv_size = sizeof(note_key);

		if ((rc = mdb_put(txn->mdb_txn, tags_db, &key, &val, 0))) {
			ndb_debug("write note tag index to db failed: %s\n",
					mdb_strerror(rc));
			return 0;
		}
	}

	return 1;
}

static int ndb_write_note_kind_index(struct ndb_txn *txn, struct ndb_note *note,
				     uint64_t note_key)
{
	struct ndb_u64_ts tsid;
	int rc;
	MDB_val key, val;
	MDB_dbi kind_db;

	ndb_u64_ts_init(&tsid, note->kind, note->created_at);

	key.mv_data = &tsid;
	key.mv_size = sizeof(tsid);
	val.mv_data = &note_key;
	val.mv_size = sizeof(note_key);

	kind_db = txn->lmdb->dbs[NDB_DB_NOTE_KIND];

	if ((rc = mdb_put(txn->mdb_txn, kind_db, &key, &val, 0))) {
		ndb_debug("write note kind index to db failed: %s\n",
				mdb_strerror(rc));
		return 0;
	}

	return 1;
}

static int ndb_write_word_to_index(struct ndb_txn *txn, const char *word,
				   int word_len, int word_index,
				   uint64_t timestamp, uint64_t note_id)
{
	// cap to some reasonable key size
	unsigned char buffer[1024];
	int keysize, rc;
	MDB_val k, v;
	MDB_dbi text_db;

	// build our compressed text index key
	if (!ndb_make_text_search_key(buffer, sizeof(buffer), word_index,
				      word_len, word, timestamp, note_id,
				      &keysize)) {
		// probably too big

		return 0;
	}

	k.mv_data = buffer;
	k.mv_size = keysize;

	v.mv_data = NULL;
	v.mv_size = 0;

	text_db = txn->lmdb->dbs[NDB_DB_NOTE_TEXT];

	if ((rc = mdb_put(txn->mdb_txn, text_db, &k, &v, 0))) {
		ndb_debug("write note text index to db failed: %s\n",
				mdb_strerror(rc));
		return 0;
	}

	return 1;
}



// break a string into individual words for querying or for building the
// fulltext search index. This is callback based so we don't need to
// build up an intermediate structure
static int ndb_parse_words(struct cursor *cur, void *ctx, ndb_word_parser_fn fn)
{
	int word_len, words;
	const char *word;

	words = 0;

	while (cur->p < cur->end) {
		consume_whitespace_or_punctuation(cur);
		if (cur->p >= cur->end)
			break;
		word = (const char *)cur->p;

		if (!consume_until_boundary(cur))
			break;

		// start of word or end
		word_len = cur->p - (unsigned char *)word;
		if (word_len == 0 && cur->p >= cur->end)
			break;

		if (word_len == 0) {
			if (!cursor_skip(cur, 1))
				break;
			continue;
		}

		//ndb_debug("writing word index '%.*s'\n", word_len, word);

		if (!fn(ctx, word, word_len, words))
			continue;

		words++;
	}

	return 1;
}

struct ndb_word_writer_ctx
{
	struct ndb_txn *txn;
	struct ndb_note *note;
	uint64_t note_id;
};

static int ndb_fulltext_word_writer(void *ctx,
		const char *word, int word_len, int words)
{
	struct ndb_word_writer_ctx *wctx = ctx;

	if (!ndb_write_word_to_index(wctx->txn, word, word_len, words,
				     wctx->note->created_at, wctx->note_id)) {
		// too big to write this one, just skip it
		ndb_debug("failed to write word '%.*s' to index\n", word_len, word);

		return 0;
	}

	//fprintf(stderr, "wrote '%.*s' to note text index\n", word_len, word);
	return 1;
}

static int ndb_write_note_fulltext_index(struct ndb_txn *txn,
					 struct ndb_note *note,
					 uint64_t note_id)
{
	struct cursor cur;
	unsigned char *content;
	struct ndb_str str;
	struct ndb_word_writer_ctx ctx;

	str = ndb_note_str(note, &note->content);
	// I don't think this should happen?
	if (unlikely(str.flag == NDB_PACKED_ID))
		return 0;

	content = (unsigned char *)str.str;

	make_cursor(content, content + note->content_length, &cur);

	ctx.txn = txn;
	ctx.note = note;
	ctx.note_id = note_id;

	ndb_parse_words(&cur, &ctx, ndb_fulltext_word_writer);

	return 1;
}

static int ndb_parse_search_words(void *ctx, const char *word_str, int word_len, int word_index)
{
	(void)word_index;
	struct ndb_search_words *words = ctx;
	struct ndb_word *word;

	if (words->num_words + 1 > MAX_TEXT_SEARCH_WORDS)
		return 0;

	word = &words->words[words->num_words++];
	word->word = word_str;
	word->word_len = word_len;

	return 1;
}

static void ndb_search_words_init(struct ndb_search_words *words)
{
	words->num_words = 0;
}

static int prefix_count(const char *str1, int len1, const char *str2, int len2) {
	int i, count = 0;
	int min_len = len1 < len2 ? len1 : len2;

	for (i = 0; i < min_len; i++) {
		// case insensitive
		if (tolower(str1[i]) == tolower(str2[i]))
			count++;
		else
			break;
	}

	return count;
}

static int ndb_prefix_matches(struct ndb_text_search_result *result,
			      struct ndb_word *search_word)
{
	// Empty strings shouldn't happen but let's
	if (result->key.str_len < 2 || search_word->word_len < 2)
		return 0;

	// make sure we at least have two matching prefix characters. exact
	// matches are nice but range searches allow us to match prefixes as
	// well. A double-char prefix is suffient, but maybe we could up this
	// in the future.
	//
	// TODO: How are we handling utf-8 prefix matches like
	// japanese?
	//
	if (   result->key.str[0] != tolower(search_word->word[0])
	    && result->key.str[1] != tolower(search_word->word[1])
	    )
		return 0;

	// count the number of prefix-matched characters. This will be used
	// for ranking search results
	result->prefix_chars = prefix_count(result->key.str,
					    result->key.str_len,
					    search_word->word,
					    search_word->word_len);

	if (result->prefix_chars <= (int)((double)search_word->word_len / 1.5))
		return 0;

	return 1;
}

// This is called when scanning the full text search index. Scanning stops
// when we no longer have a prefix match for the word
static int ndb_text_search_next_word(MDB_cursor *cursor, MDB_cursor_op op,
	MDB_val *k, struct ndb_word *search_word,
	struct ndb_text_search_result *last_result,
	struct ndb_text_search_result *result,
	MDB_cursor_op order_op)
{
	struct cursor key_cursor;
	//struct ndb_text_search_key search_key;
	MDB_val v;
	int retries;
	retries = -1;

	make_cursor(k->mv_data, (unsigned char *)k->mv_data + k->mv_size, &key_cursor);

	// When op is MDB_SET_RANGE, this initializes the search. Position
	// the cursor at the next key greater than or equal to the specified
	// key.
	//
	// Subsequent searches should use MDB_NEXT
	if (mdb_cursor_get(cursor, k, &v, op)) {
		// we should only do this if we're going in reverse
		if (op == MDB_SET_RANGE && order_op == MDB_PREV) {
			// if set range worked and our key exists, it should be
			// the one right before this one
			if (mdb_cursor_get(cursor, k, &v, MDB_PREV))
				return 0;
		} else {
			return 0;
		}
	}

retry:
	retries++;
	/*
	printf("continuing from ");
	if (ndb_unpack_text_search_key(k->mv_data, k->mv_size, &search_key)) {
		ndb_print_text_search_key(&search_key);
	} else { printf("??"); }
	printf("\n");
	*/

	make_cursor(k->mv_data, (unsigned char *)k->mv_data + k->mv_size, &key_cursor);

	if (unlikely(!ndb_unpack_text_search_key_noteid(&key_cursor, &result->key.note_id))) {
		fprintf(stderr, "UNUSUAL: failed to unpack text search key note_id\n");
		return 0;
	}

	if (last_result) {
		if (last_result->key.note_id != result->key.note_id)
			return 0;
	}

	// On success, this could still be not related at all.
	// It could just be adjacent to the word. Let's check
	// if we have a matching prefix at least.

	// Before we unpack the entire key, let's quickly
	// unpack just the string to check the prefix. We don't
	// need to unpack the entire key if the prefix doesn't
	// match
	if (!ndb_unpack_text_search_key_string(&key_cursor,
					       &result->key.str,
					       &result->key.str_len)) {
		// this should never happen
		fprintf(stderr, "UNUSUAL: failed to unpack text search key string\n");
		return 0;
	}

	if (!ndb_prefix_matches(result, search_word)) {
		/*
		printf("result prefix '%.*s' didn't match search word '%.*s'\n",
			result->key.str_len, result->key.str,
			search_word->word_len, search_word->word);
			*/
		// we should only do this if we're going in reverse
		if (retries == 0 && op == MDB_SET_RANGE && order_op == MDB_PREV) {
			// if set range worked and our key exists, it should be
			// the one right before this one
			mdb_cursor_get(cursor, k, &v, MDB_PREV);
			goto retry;
		} else {
			return 0;
		}
	}

	// Unpack the remaining text search key, we will need this information
	// when building up our search results.
	if (!ndb_unpack_remaining_text_search_key(&key_cursor, &result->key)) {
		// This should never happen
		fprintf(stderr, "UNUSUAL: failed to unpack text search key\n");
		return 0;
	}

			/*
	if (last_result) {
		if (result->key.word_index < last_result->key.word_index) {
			fprintf(stderr, "skipping '%.*s' because it is before last result '%.*s'\n",
					result->key.str_len, result->key.str,
					last_result->key.str_len, last_result->key.str);
			return 0;
		}
	}
					*/

	return 1;
}

static void ndb_text_search_results_init(
		struct ndb_text_search_results *results) {
	results->num_results = 0;
}

void ndb_default_text_search_config(struct ndb_text_search_config *cfg)
{
	cfg->order = NDB_ORDER_DESCENDING;
	cfg->limit = MAX_TEXT_SEARCH_RESULTS;
}

void ndb_text_search_config_set_order(struct ndb_text_search_config *cfg,
				     enum ndb_search_order order)
{
	cfg->order = order;
}

void ndb_text_search_config_set_limit(struct ndb_text_search_config *cfg, int limit)
{
	cfg->limit = limit;
}

int ndb_text_search(struct ndb_txn *txn, const char *query,
		    struct ndb_text_search_results *results,
		    struct ndb_text_search_config *config)
{
	unsigned char buffer[1024], *buf;
	unsigned char saved_buf[1024], *saved;
	struct ndb_text_search_result *result, *last_result;
	struct ndb_text_search_result candidate, last_candidate;
	struct ndb_search_words search_words;
	//struct ndb_text_search_key search_key;
	struct ndb_word *search_word;
	struct cursor cur;
	ndb_text_search_key_order_fn key_order_fn;
	MDB_dbi text_db;
	MDB_cursor *cursor;
	MDB_val k, v;
	int i, j, keysize, saved_size, limit;
	MDB_cursor_op op, order_op;

	saved = NULL;
	ndb_text_search_results_init(results);
	ndb_search_words_init(&search_words);

	// search config
	limit = MAX_TEXT_SEARCH_RESULTS;
	order_op = MDB_PREV;
	key_order_fn = ndb_make_text_search_key_high;
	if (config) {
		if (config->order == NDB_ORDER_ASCENDING) {
			order_op = MDB_NEXT;
			key_order_fn = ndb_make_text_search_key_low;
		}
		limit = min(limit, config->limit);
	}
	// end search config

	text_db = txn->lmdb->dbs[NDB_DB_NOTE_TEXT];
	make_cursor((unsigned char *)query, (unsigned char *)query + strlen(query), &cur);

	ndb_parse_words(&cur, &search_words, ndb_parse_search_words);
	if (search_words.num_words == 0)
		return 0;

	if ((i = mdb_cursor_open(txn->mdb_txn, text_db, &cursor))) {
		fprintf(stderr, "nd_text_search: mdb_cursor_open failed, error %d\n", i);
		return 0;
	}

	// for each word, we recursively find all of the submatches
	while (results->num_results < limit) {
		last_result = NULL;
		result = &results->results[results->num_results];

		// if we have saved, then we continue from the last root search
		// sequence
		if (saved) {
			buf = saved_buf;
			saved = NULL;
			keysize = saved_size;

			k.mv_data = buf;
			k.mv_size = saved_size;

			// reposition the cursor so we can continue
			if (mdb_cursor_get(cursor, &k, &v, MDB_SET_RANGE))
				break;

			op = order_op;
		} else {
			// construct a packed fulltext search key using this
			// word this key doesn't contain any timestamp or index
			// info, so it should range match instead of exact
			// match
			if (!key_order_fn(buffer, sizeof(buffer),
					  search_words.words[0].word_len,
					  search_words.words[0].word, &keysize))
			{
				// word is too big to fit in 1024-sized key
				continue;
			}

			buf = buffer;
			op = MDB_SET_RANGE;
		}

		for (j = 0; j < search_words.num_words; j++) {
			search_word = &search_words.words[j];

			// shouldn't happen but let's be defensive a bit
			if (search_word->word_len == 0)
				continue;

			// if we already matched a note in this phrase, make
			// sure we're including the note id in the query
			if (last_result) {
				// we are narrowing down a search.
				// if we already have this note id, just continue
				for (i = 0; i < results->num_results; i++) {
					if (results->results[i].key.note_id == last_result->key.note_id)
						goto cont;
				}

				if (!ndb_make_noted_text_search_key(
					buffer, sizeof(buffer),
					search_word->word_len,
					search_word->word,
					last_result->key.timestamp,
					last_result->key.note_id,
					&keysize))
				{
					continue;
				}

				buf = buffer;
			}

			k.mv_data = buf;
			k.mv_size = keysize;

			if (!ndb_text_search_next_word(cursor, op, &k,
						       search_word,
						       last_result,
						       &candidate,
						       order_op)) {
				break;
			}

			*result = candidate;
			op = MDB_SET_RANGE;

			// save the first key match, since we will continue from
			// this on the next root word result
			if (j == 0 && !saved) {
				memcpy(saved_buf, k.mv_data, k.mv_size);
				saved = saved_buf;
				saved_size = k.mv_size;
			}

			last_candidate = *result;
			last_result = &last_candidate;
		}

cont:
		// we matched all of the queries!
		if (j == search_words.num_words) {
			results->num_results++;
		} else if (j == 0) {
			break;
		}

	}

	mdb_cursor_close(cursor);

	return 1;
}

static void ndb_write_blocks(struct ndb_txn *txn, uint64_t note_key,
			     struct ndb_blocks *blocks)
{
	int rc;
	MDB_val key, val;

	// make sure we're not writing the owned flag to the db
	blocks->flags &= ~NDB_BLOCK_FLAG_OWNED;

	key.mv_data = &note_key;
	key.mv_size = sizeof(note_key);
	val.mv_data = blocks;
	val.mv_size = ndb_blocks_total_size(blocks);
	assert((val.mv_size % 8) == 0);

	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_BLOCKS], &key, &val, 0))) {
		ndb_debug("write version to note_blocks failed: %s\n",
				mdb_strerror(rc));
		return;
	}
}

static int ndb_write_new_blocks(struct ndb_txn *txn, struct ndb_note *note,
				uint64_t note_key, unsigned char *scratch,
				size_t scratch_size)
{
	size_t content_len;
	const char *content;
	struct ndb_blocks *blocks;

	content_len = ndb_note_content_length(note);
	content = ndb_note_content(note);

	if (!ndb_parse_content(scratch, scratch_size, content, content_len, &blocks)) {
		//ndb_debug("failed to parse content '%.*s'\n", content_len, content);
		return 0;
	}

	ndb_write_blocks(txn, note_key, blocks);
	return 1;
}

static uint64_t ndb_write_note(struct ndb_txn *txn,
			       struct ndb_writer_note *note,
			       unsigned char *scratch, size_t scratch_size)
{
	int rc;
	uint64_t note_key;
	MDB_dbi note_db;
	MDB_val key, val;

	// let's quickly sanity check if we already have this note
	if (ndb_get_notekey_by_id(txn, note->note->id))
		return 0;

	// get dbs
	note_db = txn->lmdb->dbs[NDB_DB_NOTE];

	// get new key
	note_key = ndb_get_last_key(txn->mdb_txn, note_db) + 1;

	// write note to event store
	key.mv_data = &note_key;
	key.mv_size = sizeof(note_key);
	val.mv_data = note->note;
	val.mv_size = note->note_len;

	if ((rc = mdb_put(txn->mdb_txn, note_db, &key, &val, 0))) {
		ndb_debug("write note to db failed: %s\n", mdb_strerror(rc));
		return 0;
	}

	ndb_write_note_id_index(txn, note->note, note_key);
	ndb_write_note_kind_index(txn, note->note, note_key);
	ndb_write_note_tag_index(txn, note->note, note_key);

	// only parse content and do fulltext index on text and longform notes
	if (note->note->kind == 1 || note->note->kind == 30023) {
		if (!ndb_write_note_fulltext_index(txn, note->note, note_key))
			return 0;

		// write note blocks
		ndb_write_new_blocks(txn, note->note, note_key, scratch,
				     scratch_size);
	}

	if (note->note->kind == 7) {
		ndb_write_reaction_stats(txn, note->note);
	}

	return note_key;
}

// only to be called from the writer thread
static void ndb_write_version(struct ndb_txn *txn, uint64_t version)
{
	int rc;
	MDB_val key, val;
	uint64_t version_key;

	version_key = NDB_META_KEY_VERSION;

	key.mv_data = &version_key;
	key.mv_size = sizeof(version_key);
	val.mv_data = &version;
	val.mv_size = sizeof(version);

	if ((rc = mdb_put(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NDB_META], &key, &val, 0))) {
		ndb_debug("write version to ndb_meta failed: %s\n",
				mdb_strerror(rc));
		return;
	}

	//fprintf(stderr, "writing version %" PRIu64 "\n", version);
}

static void ndb_monitor_lock(struct ndb_monitor *mon) {
	pthread_mutex_lock(&mon->mutex);
}

static void ndb_monitor_unlock(struct ndb_monitor *mon) {
	pthread_mutex_unlock(&mon->mutex);
}

struct written_note {
	uint64_t note_id;
	struct ndb_writer_note *note;
};

// When the data has been committed to the database, take all of the written
// notes, check them against subscriptions, and then write to the subscription
// inbox for all matching notes
static void ndb_notify_subscriptions(struct ndb_monitor *monitor,
				     struct written_note *wrote, int num_notes)
{
	int i, k;
	int pushed;
	struct written_note *written;
	struct ndb_note *note;
	struct ndb_subscription *sub;

	ndb_monitor_lock(monitor);

	for (i = 0; i < monitor->num_subscriptions; i++) {
		sub = &monitor->subscriptions[i];
		ndb_debug("checking subscription %d, %d notes\n", i, num_notes);

		pushed = 0;
		for (k = 0; k < num_notes; k++) {
			written = &wrote[k];
			note = written->note->note;

			if (ndb_filter_group_matches(&sub->group, note)) {
				ndb_debug("pushing note\n");

				if (!prot_queue_push(&sub->inbox, &written->note_id)) {
					ndb_debug("couldn't push note to subscriber");
				} else {
					pushed++;
				}
			} else {
				ndb_debug("not pushing note\n");
			}
		}

		// After pushing all of the matching notes, check to see if we
		// have a registered subscription callback. If so, we call it.
		// The callback needs to call ndb_poll_for_notes to pull data
		// that was just pushed to the queue in the for loop above.
		if (monitor->sub_cb != NULL && pushed > 0) {
			monitor->sub_cb(monitor->sub_cb_ctx, sub->subid);
		}
	}

	ndb_monitor_unlock(monitor);
}

static void *ndb_writer_thread(void *data)
{
	ndb_debug("started writer thread\n");
	struct ndb_writer *writer = data;
	struct ndb_writer_msg msgs[THREAD_QUEUE_BATCH], *msg;
	struct written_note written_notes[THREAD_QUEUE_BATCH];
	size_t scratch_size;
	int i, popped, done, any_note, num_notes;
	uint64_t note_nkey;
	struct ndb_txn txn;
	unsigned char *scratch;

	// 8mb scratch buffer for parsing note content
	scratch_size = 8 * 1024 * 1024;
	scratch = malloc(scratch_size);
	MDB_txn *mdb_txn = NULL;
	ndb_txn_from_mdb(&txn, writer->lmdb, mdb_txn);

	done = 0;
	while (!done) {
		txn.mdb_txn = NULL;
		num_notes = 0;
		ndb_debug("writer waiting for items\n");
		popped = prot_queue_pop_all(&writer->inbox, msgs, THREAD_QUEUE_BATCH);
		ndb_debug("writer popped %d items\n", popped);

		any_note = 0;
		for (i = 0 ; i < popped; i++) {
			msg = &msgs[i];
			switch (msg->type) {
			case NDB_WRITER_NOTE: any_note = 1; break;
			case NDB_WRITER_PROFILE: any_note = 1; break;
			case NDB_WRITER_DBMETA: any_note = 1; break;
			case NDB_WRITER_PROFILE_LAST_FETCH: any_note = 1; break;
			case NDB_WRITER_BLOCKS: any_note = 1; break;
			case NDB_WRITER_QUIT: break;
			}
		}

		if (any_note && mdb_txn_begin(txn.lmdb->env, NULL, 0, (MDB_txn **)&txn.mdb_txn))
		{
			fprintf(stderr, "writer thread txn_begin failed");
			// should definitely not happen unless DB is full
			// or something ?
			continue;
		}

		for (i = 0; i < popped; i++) {
			msg = &msgs[i];

			switch (msg->type) {
			case NDB_WRITER_QUIT:
				// quits are handled before this
				ndb_debug("writer thread got quit message\n");
				done = 1;
				continue;
			case NDB_WRITER_PROFILE:
				note_nkey =
					ndb_write_note(&txn, &msg->note,
						       scratch, scratch_size);
				if (note_nkey > 0) {
					written_notes[num_notes++] =
					(struct written_note){
						.note_id = note_nkey,
						.note = &msg->note,
					};
				} else {
					ndb_debug("failed to write note\n");
				}
				if (msg->profile.record.builder) {
					// only write if parsing didn't fail
					ndb_write_profile(&txn, &msg->profile,
							  note_nkey);
				}
				break;
			case NDB_WRITER_NOTE:
				note_nkey = ndb_write_note(&txn, &msg->note,
							   scratch,
							   scratch_size);

				if (note_nkey > 0) {
					written_notes[num_notes++] = (struct written_note){
						.note_id = note_nkey,
						.note = &msg->note,
					};
				}
				break;
			case NDB_WRITER_DBMETA:
				ndb_write_version(&txn, msg->ndb_meta.version);
				break;
			case NDB_WRITER_BLOCKS:
				ndb_write_blocks(&txn, msg->blocks.note_key,
						       msg->blocks.blocks);
				break;
			case NDB_WRITER_PROFILE_LAST_FETCH:
				ndb_writer_last_profile_fetch(&txn,
						msg->last_fetch.pubkey,
						msg->last_fetch.fetched_at
						);
				break;
			}
		}

		// commit writes
		if (any_note) {
			if (!ndb_end_query(&txn)) {
				ndb_debug("writer thread txn commit failed\n");
			} else {
				ndb_debug("notifying subscriptions, %d notes\n", num_notes);
				ndb_notify_subscriptions(writer->monitor,
							 written_notes,
							 num_notes);
				// update subscriptions
			}
		}

		// free notes
		for (i = 0; i < popped; i++) {
			msg = &msgs[i];
			if (msg->type == NDB_WRITER_NOTE) {
				free(msg->note.note);
			} else if (msg->type == NDB_WRITER_PROFILE) {
				free(msg->profile.note.note);
				//ndb_profile_record_builder_free(&msg->profile.record);
			}  else if (msg->type == NDB_WRITER_BLOCKS) {
				ndb_blocks_free(msg->blocks.blocks);
			}
		}
	}

	free(scratch);
	ndb_debug("quitting writer thread\n");
	return NULL;
}

static void *ndb_ingester_thread(void *data)
{
	secp256k1_context *ctx;
	struct thread *thread = data;
	struct ndb_ingester *ingester = (struct ndb_ingester *)thread->ctx;
	struct ndb_lmdb *lmdb = ingester->lmdb;
	struct ndb_ingester_msg msgs[THREAD_QUEUE_BATCH], *msg;
	struct ndb_writer_msg outs[THREAD_QUEUE_BATCH], *out;
	int i, to_write, popped, done, any_event;
	MDB_txn *read_txn = NULL;
	int rc;

	ctx = secp256k1_context_create(SECP256K1_CONTEXT_VERIFY);
	ndb_debug("started ingester thread\n");

	done = 0;
	while (!done) {
		to_write = 0;
		any_event = 0;

		popped = prot_queue_pop_all(&thread->inbox, msgs, THREAD_QUEUE_BATCH);
		ndb_debug("ingester popped %d items\n", popped);

		for (i = 0; i < popped; i++) {
			msg = &msgs[i];
			if (msg->type == NDB_INGEST_EVENT) {
				any_event = 1;
				break;
			}
		}

		if (any_event && (rc = mdb_txn_begin(lmdb->env, NULL, MDB_RDONLY, &read_txn))) {
			// this is bad
			fprintf(stderr, "UNUSUAL ndb_ingester: mdb_txn_begin failed: '%s'\n",
					mdb_strerror(rc));
			continue;
		}

		for (i = 0; i < popped; i++) {
			msg = &msgs[i];
			switch (msg->type) {
			case NDB_INGEST_QUIT:
				done = 1;
				break;

			case NDB_INGEST_EVENT:
				out = &outs[to_write];
				if (ndb_ingester_process_event(ctx, ingester,
							       &msg->event, out,
							       read_txn)) {
					to_write++;
				}
			}
		}

		if (any_event)
			mdb_txn_abort(read_txn);

		if (to_write > 0) {
			ndb_debug("pushing %d events to write queue\n", to_write);
			if (!prot_queue_push_all(ingester->writer_inbox, outs, to_write)) {
				ndb_debug("failed pushing %d events to write queue\n", to_write);
			}
		}
	}

	ndb_debug("quitting ingester thread\n");
	secp256k1_context_destroy(ctx);
	return NULL;
}


static int ndb_writer_init(struct ndb_writer *writer, struct ndb_lmdb *lmdb,
			   struct ndb_monitor *monitor)
{
	writer->lmdb = lmdb;
	writer->monitor = monitor;
	writer->queue_buflen = sizeof(struct ndb_writer_msg) * DEFAULT_QUEUE_SIZE;
	writer->queue_buf = malloc(writer->queue_buflen);
	if (writer->queue_buf == NULL) {
		fprintf(stderr, "ndb: failed to allocate space for writer queue");
		return 0;
	}

	// init the writer queue.
	prot_queue_init(&writer->inbox, writer->queue_buf,
			writer->queue_buflen, sizeof(struct ndb_writer_msg));

	// spin up the writer thread
	if (THREAD_CREATE(writer->thread_id, ndb_writer_thread, writer))
	{
		fprintf(stderr, "ndb writer thread failed to create\n");
		return 0;
	}

	return 1;
}

// initialize the ingester queue and then spawn the thread
static int ndb_ingester_init(struct ndb_ingester *ingester,
			     struct ndb_lmdb *lmdb,
			     struct prot_queue *writer_inbox,
			     const struct ndb_config *config)
{
	int elem_size, num_elems;
	static struct ndb_ingester_msg quit_msg = { .type = NDB_INGEST_QUIT };

	// TODO: configurable queue sizes
	elem_size = sizeof(struct ndb_ingester_msg);
	num_elems = DEFAULT_QUEUE_SIZE;

	ingester->writer_inbox = writer_inbox;
	ingester->lmdb = lmdb;
	ingester->flags = config->flags;
	ingester->filter = config->ingest_filter;
	ingester->filter_context = config->filter_context;

	if (!threadpool_init(&ingester->tp, config->ingester_threads,
			     elem_size, num_elems, &quit_msg, ingester,
			     ndb_ingester_thread))
	{
		fprintf(stderr, "ndb ingester threadpool failed to init\n");
		return 0;
	}

	return 1;
}

static int ndb_writer_destroy(struct ndb_writer *writer)
{
	struct ndb_writer_msg msg;

	// kill thread
	msg.type = NDB_WRITER_QUIT;
	ndb_debug("writer: pushing quit message\n");
	if (!prot_queue_push(&writer->inbox, &msg)) {
		// queue is too full to push quit message. just kill it.
		ndb_debug("writer: terminating thread\n");
		THREAD_TERMINATE(writer->thread_id);
	} else {
		ndb_debug("writer: joining thread\n");
		THREAD_FINISH(writer->thread_id);
	}

	// cleanup
	ndb_debug("writer: cleaning up protected queue\n");
	prot_queue_destroy(&writer->inbox);

	free(writer->queue_buf);

	return 1;
}

static int ndb_ingester_destroy(struct ndb_ingester *ingester)
{
	threadpool_destroy(&ingester->tp);
	return 1;
}

static int ndb_init_lmdb(const char *filename, struct ndb_lmdb *lmdb, size_t mapsize)
{
	int rc;
	MDB_txn *txn;

	if ((rc = mdb_env_create(&lmdb->env))) {
		fprintf(stderr, "mdb_env_create failed, error %d\n", rc);
		return 0;
	}

	if ((rc = mdb_env_set_mapsize(lmdb->env, mapsize))) {
		fprintf(stderr, "mdb_env_set_mapsize failed, error %d\n", rc);
		return 0;
	}

	if ((rc = mdb_env_set_maxdbs(lmdb->env, NDB_DBS))) {
		fprintf(stderr, "mdb_env_set_maxdbs failed, error %d\n", rc);
		return 0;
	}

	if ((rc = mdb_env_open(lmdb->env, filename, 0, 0664))) {
		fprintf(stderr, "mdb_env_open failed, error %d\n", rc);
		return 0;
	}

	// Initialize DBs
	if ((rc = mdb_txn_begin(lmdb->env, NULL, 0, &txn))) {
		fprintf(stderr, "mdb_txn_begin failed, error %d\n", rc);
		return 0;
	}

	// note flatbuffer db
	if ((rc = mdb_dbi_open(txn, "note", MDB_CREATE | MDB_INTEGERKEY, &lmdb->dbs[NDB_DB_NOTE]))) {
		fprintf(stderr, "mdb_dbi_open event failed, error %d\n", rc);
		return 0;
	}

	// note metadata db
	if ((rc = mdb_dbi_open(txn, "meta", MDB_CREATE, &lmdb->dbs[NDB_DB_META]))) {
		fprintf(stderr, "mdb_dbi_open meta failed, error %d\n", rc);
		return 0;
	}

	// profile flatbuffer db
	if ((rc = mdb_dbi_open(txn, "profile", MDB_CREATE | MDB_INTEGERKEY, &lmdb->dbs[NDB_DB_PROFILE]))) {
		fprintf(stderr, "mdb_dbi_open profile failed, error %d\n", rc);
		return 0;
	}

	// profile search db
	if ((rc = mdb_dbi_open(txn, "profile_search", MDB_CREATE, &lmdb->dbs[NDB_DB_PROFILE_SEARCH]))) {
		fprintf(stderr, "mdb_dbi_open profile_search failed, error %d\n", rc);
		return 0;
	}
	mdb_set_compare(txn, lmdb->dbs[NDB_DB_PROFILE_SEARCH], ndb_search_key_cmp);

	// ndb metadata (db version, etc)
	if ((rc = mdb_dbi_open(txn, "ndb_meta", MDB_CREATE | MDB_INTEGERKEY, &lmdb->dbs[NDB_DB_NDB_META]))) {
		fprintf(stderr, "mdb_dbi_open ndb_meta failed, error %d\n", rc);
		return 0;
	}

	// profile last fetches
	if ((rc = mdb_dbi_open(txn, "profile_last_fetch", MDB_CREATE, &lmdb->dbs[NDB_DB_PROFILE_LAST_FETCH]))) {
		fprintf(stderr, "mdb_dbi_open profile last fetch, error %d\n", rc);
		return 0;
	}

	// id+ts index flags
	unsigned int tsid_flags = MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED;

	// index dbs
	if ((rc = mdb_dbi_open(txn, "note_id", tsid_flags, &lmdb->dbs[NDB_DB_NOTE_ID]))) {
		fprintf(stderr, "mdb_dbi_open id failed: %s\n", mdb_strerror(rc));
		return 0;
	}
	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_ID], ndb_tsid_compare);

	if ((rc = mdb_dbi_open(txn, "profile_pk", tsid_flags, &lmdb->dbs[NDB_DB_PROFILE_PK]))) {
		fprintf(stderr, "mdb_dbi_open profile_pk failed: %s\n", mdb_strerror(rc));
		return 0;
	}
	mdb_set_compare(txn, lmdb->dbs[NDB_DB_PROFILE_PK], ndb_tsid_compare);

	if ((rc = mdb_dbi_open(txn, "note_kind",
			       MDB_CREATE | MDB_DUPSORT | MDB_INTEGERDUP | MDB_DUPFIXED,
			       &lmdb->dbs[NDB_DB_NOTE_KIND]))) {
		fprintf(stderr, "mdb_dbi_open note_kind failed: %s\n", mdb_strerror(rc));
		return 0;
	}
	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_KIND], ndb_u64_ts_compare);

	if ((rc = mdb_dbi_open(txn, "note_text", MDB_CREATE | MDB_DUPSORT,
			       &lmdb->dbs[NDB_DB_NOTE_TEXT]))) {
		fprintf(stderr, "mdb_dbi_open note_text failed: %s\n", mdb_strerror(rc));
		return 0;
	}
	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_TEXT], ndb_text_search_key_compare);

	if ((rc = mdb_dbi_open(txn, "note_blocks", MDB_CREATE | MDB_INTEGERKEY,
			       &lmdb->dbs[NDB_DB_NOTE_BLOCKS]))) {
		fprintf(stderr, "mdb_dbi_open note_blocks failed: %s\n", mdb_strerror(rc));
		return 0;
	}

	if ((rc = mdb_dbi_open(txn, "note_tags", MDB_CREATE | MDB_DUPSORT | MDB_DUPFIXED,
			       &lmdb->dbs[NDB_DB_NOTE_TAGS]))) {
		fprintf(stderr, "mdb_dbi_open note_tags failed: %s\n", mdb_strerror(rc));
		return 0;
	}
	mdb_set_compare(txn, lmdb->dbs[NDB_DB_NOTE_TAGS], ndb_tag_key_compare);

	// Commit the transaction
	if ((rc = mdb_txn_commit(txn))) {
		fprintf(stderr, "mdb_txn_commit failed, error %d\n", rc);
		return 0;
	}

	return 1;
}

static int ndb_queue_write_version(struct ndb *ndb, uint64_t version)
{
	struct ndb_writer_msg msg;
	msg.type = NDB_WRITER_DBMETA;
	msg.ndb_meta.version = version;
	return ndb_writer_queue_msg(&ndb->writer, &msg);
}

static int ndb_run_migrations(struct ndb *ndb)
{
	int64_t version, latest_version, i;

	latest_version = sizeof(MIGRATIONS) / sizeof(MIGRATIONS[0]);

	if ((version = ndb_db_version(ndb)) == -1) {
		ndb_debug("run_migrations: no version found, assuming new db\n");
		version = latest_version;

		// no version found. fresh db?
		if (!ndb_queue_write_version(ndb, version)) {
			fprintf(stderr, "run_migrations: failed writing db version");
			return 0;
		}

		return 1;
	} else {
		ndb_debug("ndb: version %" PRIu64 " found\n", version);
	}

	if (version < latest_version)
		ndb_debug("nostrdb: migrating v%d -> v%d\n",
				(int)version, (int)latest_version);

	for (i = version; i < latest_version; i++) {
		if (!MIGRATIONS[i].fn(ndb)) {
			fprintf(stderr, "run_migrations: migration v%d -> v%d failed\n", (int)i, (int)(i+1));
			return 0;
		}

		if (!ndb_queue_write_version(ndb, i+1)) {
			fprintf(stderr, "run_migrations: failed writing db version");
			return 0;
		}

		version = i+1;
	}

	ndb->version = version;

	return 1;
}

static void ndb_monitor_init(struct ndb_monitor *monitor, ndb_sub_fn cb,
			     void *sub_cb_ctx)
{
	monitor->num_subscriptions = 0;
	monitor->sub_cb = cb;
	monitor->sub_cb_ctx = sub_cb_ctx;
	pthread_mutex_init(&monitor->mutex, NULL);
}

void ndb_filter_group_destroy(struct ndb_filter_group *group)
{
	struct ndb_filter *filter;
	int i;
	for (i = 0; i < group->num_filters; i++) {
		filter = &group->filters[i];
		ndb_filter_destroy(filter);
	}
}

static void ndb_subscription_destroy(struct ndb_subscription *sub)
{
	ndb_filter_group_destroy(&sub->group);
	prot_queue_destroy(&sub->inbox);
	sub->subid = 0;
}

static void ndb_monitor_destroy(struct ndb_monitor *monitor)
{
	int i;

	for (i = 0; i < monitor->num_subscriptions; i++) {
		ndb_subscription_destroy(&monitor->subscriptions[i]);
	}
}

int ndb_init(struct ndb **pndb, const char *filename, const struct ndb_config *config)
{
	struct ndb *ndb;
	//MDB_dbi ind_id; // TODO: ind_pk, etc

	ndb = *pndb = calloc(1, sizeof(struct ndb));
	ndb->flags = config->flags;

	if (ndb == NULL) {
		fprintf(stderr, "ndb_init: malloc failed\n");
		return 0;
	}

	if (!ndb_init_lmdb(filename, &ndb->lmdb, config->mapsize))
		return 0;

	ndb_monitor_init(&ndb->monitor, config->sub_cb, config->sub_cb_ctx);

	if (!ndb_writer_init(&ndb->writer, &ndb->lmdb, &ndb->monitor)) {
		fprintf(stderr, "ndb_writer_init failed\n");
		return 0;
	}

	if (!ndb_ingester_init(&ndb->ingester, &ndb->lmdb, &ndb->writer.inbox, config)) {
		fprintf(stderr, "failed to initialize %d ingester thread(s)\n",
				config->ingester_threads);
		return 0;
	}

	if (!ndb_flag_set(config->flags, NDB_FLAG_NOMIGRATE) &&
			  !ndb_run_migrations(ndb)) {
		fprintf(stderr, "failed to run migrations\n");
		return 0;
	}

	// Initialize LMDB environment and spin up threads
	return 1;
}

void ndb_destroy(struct ndb *ndb)
{
	if (ndb == NULL)
		return;

	// ingester depends on writer and must be destroyed first
	ndb_debug("destroying ingester\n");
	ndb_ingester_destroy(&ndb->ingester);
	ndb_debug("destroying writer\n");
	ndb_writer_destroy(&ndb->writer);
	ndb_debug("destroying monitor\n");
	ndb_monitor_destroy(&ndb->monitor);

	ndb_debug("closing env\n");
	mdb_env_close(ndb->lmdb.env);

	ndb_debug("ndb destroyed\n");
	free(ndb);
}

// Process a nostr event from a client
//
// ie: ["EVENT", {"content":"..."} ...]
//
// The client-sent variation of ndb_process_event
int ndb_process_client_event(struct ndb *ndb, const char *json, int len)
{
	return ndb_ingest_event(&ndb->ingester, json, len, 1);
}

// Process anostr event from a relay,
//
// ie: ["EVENT", "subid", {"content":"..."}...]
//
// This function returns as soon as possible, first copying the passed
// json and then queueing it up for processing. Worker threads then take
// the json and process it.
//
// Processing:
//
// 1. The event is parsed into ndb_notes and the signature is validated
// 2. A quick lookup is made on the database to see if we already have
//    the note id, if we do we don't need to waste time on json parsing
//    or note validation.
// 3. Once validation is done we pass it to the writer queue for writing
//    to LMDB.
//
int ndb_process_event(struct ndb *ndb, const char *json, int json_len)
{
	return ndb_ingest_event(&ndb->ingester, json, json_len, 0);
}


int _ndb_process_events(struct ndb *ndb, const char *ldjson, size_t json_len, int client)
{
	const char *start, *end, *very_end;
	start = ldjson;
	end = start + json_len;
	very_end = ldjson + json_len;
	int (* process)(struct ndb *, const char *, int);
#if DEBUG
	int processed = 0;
#endif
	process = client ? ndb_process_client_event : ndb_process_event;

	while ((end = fast_strchr(start, '\n', very_end - start))) {
		//printf("processing '%.*s'\n", (int)(end-start), start);
		if (!process(ndb, start, end - start)) {
			ndb_debug("ndb_process_client_event failed\n");
			return 0;
		}
		start = end + 1;
#if DEBUG
		processed++;
#endif
	}

#if DEBUG
	ndb_debug("ndb_process_events: processed %d events\n", processed);
#endif

	return 1;
}

#ifndef _WIN32
// TODO: windows
int ndb_process_events_stream(struct ndb *ndb, FILE* fp)
{
	char *line = NULL;
	size_t len = 0;
	ssize_t nread;

	while ((nread = getline(&line, &len, fp)) != -1) {
		if (line == NULL)
			break;
		ndb_process_event(ndb, line, len);
	}

	if (line)
		free(line);

	return 1;
}
#endif

int ndb_process_client_events(struct ndb *ndb, const char *ldjson, size_t json_len)
{
	return _ndb_process_events(ndb, ldjson, json_len, 1);
}

int ndb_process_events(struct ndb *ndb, const char *ldjson, size_t json_len)
{
	return _ndb_process_events(ndb, ldjson, json_len, 0);
}

static inline int cursor_push_tag(struct cursor *cur, struct ndb_tag *tag)
{
	return cursor_push_u16(cur, tag->count);
}

int ndb_builder_init(struct ndb_builder *builder, unsigned char *buf,
		     size_t bufsize)
{
	struct ndb_note *note;
	int half, size, str_indices_size;

	// come on bruh
	if (bufsize < sizeof(struct ndb_note) * 2)
		return 0;

	str_indices_size = bufsize / 32;
	size = bufsize - str_indices_size;
	half = size / 2;

	//debug("size %d half %d str_indices %d\n", size, half, str_indices_size);

	// make a safe cursor of our available memory
	make_cursor(buf, buf + bufsize, &builder->mem);

	note = builder->note = (struct ndb_note *)buf;

	// take slices of the memory into subcursors
	if (!(cursor_slice(&builder->mem, &builder->note_cur, half) &&
	      cursor_slice(&builder->mem, &builder->strings, half) &&
	      cursor_slice(&builder->mem, &builder->str_indices, str_indices_size))) {
		return 0;
	}

	memset(note, 0, sizeof(*note));
	builder->note_cur.p += sizeof(*note);

	note->strings = builder->strings.start - buf;
	note->version = 1;

	return 1;
}



static inline int ndb_json_parser_init(struct ndb_json_parser *p,
				       const char *json, int json_len,
				       unsigned char *buf, int bufsize)
{
	int half = bufsize / 2;

	unsigned char *tok_start = buf + half;
	unsigned char *tok_end = buf + bufsize;

	p->toks = (jsmntok_t*)tok_start;
	p->toks_end = (jsmntok_t*)tok_end;
	p->num_tokens = 0;
	p->json = json;
	p->json_len = json_len;

	// ndb_builder gets the first half of the buffer, and jsmn gets the
	// second half. I like this way of alloating memory (without actually
	// dynamically allocating memory). You get one big chunk upfront and
	// then submodules can recursively subdivide it. Maybe you could do
	// something even more clever like golden-ratio style subdivision where
	// the more important stuff gets a larger chunk and then it spirals
	// downward into smaller chunks. Thanks for coming to my TED talk.

	if (!ndb_builder_init(&p->builder, buf, half))
		return 0;

	jsmn_init(&p->json_parser);

	return 1;
}

static inline int ndb_json_parser_parse(struct ndb_json_parser *p,
					struct ndb_id_cb *cb)
{
	jsmntok_t *tok;
	int cap = ((unsigned char *)p->toks_end - (unsigned char*)p->toks)/sizeof(*p->toks);
	int res =
		jsmn_parse(&p->json_parser, p->json, p->json_len, p->toks, cap, cb != NULL);

	// got an ID!
	if (res == -42) {
		tok = &p->toks[p->json_parser.toknext-1];

		switch (cb->fn(cb->data, p->json + tok->start)) {
		case NDB_IDRES_CONT:
			res = jsmn_parse(&p->json_parser, p->json, p->json_len,
					 p->toks, cap, 0);
			break;
		case NDB_IDRES_STOP:
			return -42;
		}
	} else if (res == 0) {
		return 0;
	}

	p->num_tokens = res;
	p->i = 0;

	return 1;
}

static inline int toksize(jsmntok_t *tok)
{
	return tok->end - tok->start;
}



static int cursor_push_unescaped_char(struct cursor *cur, char c1, char c2)
{
	switch (c2) {
	case 't':  return cursor_push_byte(cur, '\t');
	case 'n':  return cursor_push_byte(cur, '\n');
	case 'r':  return cursor_push_byte(cur, '\r');
	case 'b':  return cursor_push_byte(cur, '\b');
	case 'f':  return cursor_push_byte(cur, '\f');
	case '\\': return cursor_push_byte(cur, '\\');
	case '/':  return cursor_push_byte(cur, '/');
	case '"':  return cursor_push_byte(cur, '"');
	case 'u':
		// these aren't handled yet
		return 0;
	default:
		return cursor_push_byte(cur, c1) && cursor_push_byte(cur, c2);
	}
}

static int cursor_push_escaped_char(struct cursor *cur, char c)
{
        switch (c) {
        case '"':  return cursor_push_str(cur, "\\\"");
        case '\\': return cursor_push_str(cur, "\\\\");
        case '\b': return cursor_push_str(cur, "\\b");
        case '\f': return cursor_push_str(cur, "\\f");
        case '\n': return cursor_push_str(cur, "\\n");
        case '\r': return cursor_push_str(cur, "\\r");
        case '\t': return cursor_push_str(cur, "\\t");
        // TODO: \u hex hex hex hex
        }
        return cursor_push_byte(cur, c);
}

static int cursor_push_hex_str(struct cursor *cur, unsigned char *buf, int len)
{
	int i;

	if (len % 2 != 0)
		return 0;

        if (!cursor_push_byte(cur, '"'))
                return 0;

	for (i = 0; i < len; i++) {
		unsigned int c = ((const unsigned char *)buf)[i];
		if (!cursor_push_byte(cur, hexchar(c >> 4)))
			return 0;
		if (!cursor_push_byte(cur, hexchar(c & 0xF)))
			return 0;
	}

        if (!cursor_push_byte(cur, '"'))
                return 0;

	return 1;
}

static int cursor_push_jsonstr(struct cursor *cur, const char *str)
{
	int i;
        int len;

	len = strlen(str);

        if (!cursor_push_byte(cur, '"'))
                return 0;

        for (i = 0; i < len; i++) {
                if (!cursor_push_escaped_char(cur, str[i]))
                        return 0;
        }

        if (!cursor_push_byte(cur, '"'))
                return 0;

        return 1;
}


static inline int cursor_push_json_tag_str(struct cursor *cur, struct ndb_str str)
{
	if (str.flag == NDB_PACKED_ID)
		return cursor_push_hex_str(cur, str.id, 32);

	return cursor_push_jsonstr(cur, str.str);
}

static int cursor_push_json_tag(struct cursor *cur, struct ndb_note *note,
				struct ndb_tag *tag)
{
        int i;

        if (!cursor_push_byte(cur, '['))
                return 0;

        for (i = 0; i < tag->count; i++) {
                if (!cursor_push_json_tag_str(cur, ndb_tag_str(note, tag, i)))
                        return 0;
                if (i != tag->count-1 && !cursor_push_byte(cur, ','))
			return 0;
        }

        return cursor_push_byte(cur, ']');
}

static int cursor_push_json_tags(struct cursor *cur, struct ndb_note *note)
{
	int i;
	struct ndb_iterator iter, *it = &iter;
	ndb_tags_iterate_start(note, it);

        if (!cursor_push_byte(cur, '['))
                return 0;

	i = 0;
	while (ndb_tags_iterate_next(it)) {
		if (!cursor_push_json_tag(cur, note, it->tag))
			return 0;
                if (i != note->tags.count-1 && !cursor_push_str(cur, ","))
			return 0;
		i++;
	}

        if (!cursor_push_byte(cur, ']'))
                return 0;

	return 1;
}

static int ndb_event_commitment(struct ndb_note *ev, unsigned char *buf, int buflen)
{
	char timebuf[16] = {0};
	char kindbuf[16] = {0};
	char pubkey[65];
	struct cursor cur;
	int ok;

	if (!hex_encode(ev->pubkey, sizeof(ev->pubkey), pubkey))
		return 0;

	make_cursor(buf, buf + buflen, &cur);

	// TODO: update in 2106 ...
	snprintf(timebuf, sizeof(timebuf), "%d", (uint32_t)ev->created_at);
	snprintf(kindbuf, sizeof(kindbuf), "%d", ev->kind);

	ok =
		cursor_push_str(&cur, "[0,\"") &&
		cursor_push_str(&cur, pubkey) &&
		cursor_push_str(&cur, "\",") &&
		cursor_push_str(&cur, timebuf) &&
		cursor_push_str(&cur, ",") &&
		cursor_push_str(&cur, kindbuf) &&
		cursor_push_str(&cur, ",") &&
		cursor_push_json_tags(&cur, ev) &&
		cursor_push_str(&cur, ",") &&
		cursor_push_jsonstr(&cur, ndb_note_str(ev, &ev->content).str) &&
		cursor_push_str(&cur, "]");

	if (!ok)
		return 0;

	return cur.p - cur.start;
}

static int cursor_push_hex(struct cursor *c, unsigned char *bytes, int len)
{
	int i;
	unsigned char chr;
	if (c->p + (len * 2) >= c->end)
		return 0;

	for (i = 0; i < len; i++) {
		chr = bytes[i];

		*(c->p++) = hexchar(chr >> 4);
		*(c->p++) = hexchar(chr & 0xF);
	}

	return 1;
}

static int cursor_push_int_str(struct cursor *c, uint64_t num)
{
	char timebuf[16] = {0};
	snprintf(timebuf, sizeof(timebuf), "%" PRIu64, num);
	return cursor_push_str(c, timebuf);
}

int ndb_note_json(struct ndb_note *note, char *buf, int buflen)
{
	struct cursor cur, *c = &cur;

	make_cursor((unsigned char *)buf, (unsigned char*)buf + buflen, &cur);

	int ok = cursor_push_str(c, "{\"id\":\"") &&
	       cursor_push_hex(c, ndb_note_id(note), 32) &&
	       cursor_push_str(c, "\",\"pubkey\":\"") &&
	       cursor_push_hex(c, ndb_note_pubkey(note), 32) &&
	       cursor_push_str(c, "\",\"created_at\":") &&
	       cursor_push_int_str(c, ndb_note_created_at(note)) &&
	       cursor_push_str(c, ",\"kind\":") &&
	       cursor_push_int_str(c, ndb_note_kind(note)) &&
	       cursor_push_str(c, ",\"tags\":") &&
	       cursor_push_json_tags(c, note) &&
	       cursor_push_str(c, ",\"content\":") &&
	       cursor_push_jsonstr(c, ndb_note_content(note)) &&
	       cursor_push_str(c, ",\"sig\":\"") &&
	       cursor_push_hex(c, ndb_note_sig(note), 64) &&
	       cursor_push_c_str(c, "\"}");

	if (!ok) {
		return 0;
	}

	return cur.p - cur.start;
}

static int cursor_push_json_elem_array(struct cursor *cur,
				       const struct ndb_filter *filter,
				       struct ndb_filter_elements *elems)
{
	int i;
	unsigned char *id;
	const char *str;
	uint64_t val;

	if (!cursor_push_byte(cur, '['))
		return 0;

	for (i = 0; i < elems->count; i++) {

		switch (elems->field.elem_type)  {
		case NDB_ELEMENT_STRING:
			str = ndb_filter_get_string_element(filter, elems, i);
			if (!cursor_push_jsonstr(cur, str))
				return 0;
			break;
		case NDB_ELEMENT_ID:
			id = ndb_filter_get_id_element(filter, elems, i);
			if (!cursor_push_hex_str(cur, id, 32))
				return 0;
			break;
		case NDB_ELEMENT_INT:
			val = ndb_filter_get_int_element(elems, i);
			if (!cursor_push_int_str(cur, val))
				return 0;
			break;
		case NDB_ELEMENT_UNKNOWN:
			ndb_debug("unknown element in cursor_push_json_elem_array");
			return 0;
		}

		if (i != elems->count-1) {
			if (!cursor_push_byte(cur, ','))
				return 0;
		}
	}

	if (!cursor_push_str(cur, "]"))
		return 0;

	return 1;
}

int ndb_filter_json(const struct ndb_filter *filter, char *buf, int buflen)
{
	struct cursor cur, *c = &cur;
	struct ndb_filter_elements *elems;
	int i;

	if (!filter->finalized) {
		ndb_debug("filter not finalized in ndb_filter_json\n");
		return 0;
	}

	make_cursor((unsigned char *)buf, (unsigned char*)buf + buflen, c);

	if (!cursor_push_str(c, "{"))
		return 0;

	for (i = 0; i < filter->num_elements; i++) {
		elems = ndb_filter_get_elements(filter, i);
		switch (elems->field.type) {
		case NDB_FILTER_IDS:
			if (!cursor_push_str(c, "\"ids\":"))
				return 0;
			if (!cursor_push_json_elem_array(c, filter, elems))
				return 0;
			break;
		case NDB_FILTER_AUTHORS:
			if (!cursor_push_str(c, "\"authors\":"))
				return 0;
			if (!cursor_push_json_elem_array(c, filter, elems))
				return 0;
			break;
		case NDB_FILTER_KINDS:
			if (!cursor_push_str(c, "\"kinds\":"))
				return 0;
			if (!cursor_push_json_elem_array(c, filter, elems))
				return 0;
			break;
		case NDB_FILTER_TAGS:
			if (!cursor_push_str(c, "\"#"))
				return 0;
			if (!cursor_push_byte(c, elems->field.tag))
				return 0;
			if (!cursor_push_str(c, "\":"))
				return 0;
			if (!cursor_push_json_elem_array(c, filter, elems))
				return 0;
			break;
		case NDB_FILTER_SINCE:
			if (!cursor_push_str(c, "\"since\":"))
				return 0;
			if (!cursor_push_int_str(c, ndb_filter_get_int_element(elems, 0)))
				return 0;
			break;
		case NDB_FILTER_UNTIL:
			if (!cursor_push_str(c, "\"until\":"))
				return 0;
			if (!cursor_push_int_str(c, ndb_filter_get_int_element(elems, 0)))
				return 0;
			break;
		case NDB_FILTER_LIMIT:
			if (!cursor_push_str(c, "\"limit\":"))
				return 0;
			if (!cursor_push_int_str(c, ndb_filter_get_int_element(elems, 0)))
				return 0;
			break;
		}

		if (i != filter->num_elements-1) {
			if (!cursor_push_byte(c, ',')) {
				return 0;
			}
		}

	}

	if (!cursor_push_c_str(c, "}"))
		return 0;

	return cur.p - cur.start;
}

int ndb_calculate_id(struct ndb_note *note, unsigned char *buf, int buflen) {
	int len;

	if (!(len = ndb_event_commitment(note, buf, buflen)))
		return 0;

	//fprintf(stderr, "%.*s\n", len, buf);

	sha256((struct sha256*)note->id, buf, len);

	return 1;
}

int ndb_sign_id(struct ndb_keypair *keypair, unsigned char id[32],
		unsigned char sig[64])
{
	unsigned char aux[32];
	secp256k1_keypair *pair = (secp256k1_keypair*) keypair->pair;

	if (!fill_random(aux, sizeof(aux)))
		return 0;

	secp256k1_context *ctx =
		secp256k1_context_create(SECP256K1_CONTEXT_NONE);

	return secp256k1_schnorrsig_sign32(ctx, sig, id, pair, aux);
}

int ndb_create_keypair(struct ndb_keypair *kp)
{
	secp256k1_keypair *keypair = (secp256k1_keypair*)kp->pair;
	secp256k1_xonly_pubkey pubkey;

	secp256k1_context *ctx =
		secp256k1_context_create(SECP256K1_CONTEXT_NONE);;

	/* Try to create a keypair with a valid context, it should only
	 * fail if the secret key is zero or out of range. */
	if (!secp256k1_keypair_create(ctx, keypair, kp->secret))
		return 0;

	if (!secp256k1_keypair_xonly_pub(ctx, &pubkey, NULL, keypair))
		return 0;

	/* Serialize the public key. Should always return 1 for a valid public key. */
	return secp256k1_xonly_pubkey_serialize(ctx, kp->pubkey, &pubkey);
}

int ndb_decode_key(const char *secstr, struct ndb_keypair *keypair)
{
	if (!hex_decode(secstr, strlen(secstr), keypair->secret, 32)) {
		fprintf(stderr, "could not hex decode secret key\n");
		return 0;
	}

	return ndb_create_keypair(keypair);
}

int ndb_builder_finalize(struct ndb_builder *builder, struct ndb_note **note,
			 struct ndb_keypair *keypair)
{
	int strings_len = builder->strings.p - builder->strings.start;
	unsigned char *note_end = builder->note_cur.p + strings_len;
	int total_size = note_end - builder->note_cur.start;

	// move the strings buffer next to the end of our ndb_note
	memmove(builder->note_cur.p, builder->strings.start, strings_len);

	// set the strings location
	builder->note->strings = builder->note_cur.p - builder->note_cur.start;

	// record the total size
	//builder->note->size = total_size;

	*note = builder->note;

	// generate id and sign if we're building this manually
	if (keypair) {
		// use the remaining memory for building our id buffer
		unsigned char *end   = builder->mem.end;
		unsigned char *start = (unsigned char*)(*note) + total_size;

		ndb_builder_set_pubkey(builder, keypair->pubkey);

		if (!ndb_calculate_id(builder->note, start, end - start))
			return 0;

		if (!ndb_sign_id(keypair, (*note)->id, (*note)->sig))
			return 0;
	}

	// make sure we're aligned as a whole
	total_size = (total_size + 7) & ~7;
	assert((total_size % 8) == 0);
	return total_size;
}

struct ndb_note * ndb_builder_note(struct ndb_builder *builder)
{
	return builder->note;
}

static union ndb_packed_str ndb_offset_str(uint32_t offset)
{
	// ensure accidents like -1 don't corrupt our packed_str
	union ndb_packed_str str;
	// most significant byte is reserved for ndb_packtype
	str.offset = offset & 0xFFFFFF;
	return str;
}


/// find an existing string via str_indices. these indices only exist in the
/// builder phase just for this purpose.
static inline int ndb_builder_find_str(struct ndb_builder *builder,
				       const char *str, int len,
				       union ndb_packed_str *pstr)
{
	// find existing matching string to avoid duplicate strings
	int indices = cursor_count(&builder->str_indices, sizeof(uint32_t));
	for (int i = 0; i < indices; i++) {
		uint32_t index = ((uint32_t*)builder->str_indices.start)[i];
		const char *some_str = (const char*)builder->strings.start + index;

		if (!memcmp(some_str, str, len) && some_str[len] == '\0') {
			// found an existing matching str, use that index
			*pstr = ndb_offset_str(index);
			return 1;
		}
	}

	return 0;
}

static int ndb_builder_push_str(struct ndb_builder *builder, const char *str,
				int len, union ndb_packed_str *pstr)
{
	uint32_t loc;

	// no string found, push a new one
	loc = builder->strings.p - builder->strings.start;
	if (!(cursor_push(&builder->strings, (unsigned char*)str, len) &&
	      cursor_push_byte(&builder->strings, '\0'))) {
		return 0;
	}

	*pstr = ndb_offset_str(loc);

	// record in builder indices. ignore return value, if we can't cache it
	// then whatever
	cursor_push_u32(&builder->str_indices, loc);

	return 1;
}

static int ndb_builder_push_packed_id(struct ndb_builder *builder,
				      unsigned char *id,
				      union ndb_packed_str *pstr)
{
	// Don't both find id duplicates. very rarely are they duplicated
	// and it slows things down quite a bit. If we really care about this
	// We can switch to a hash table.
	//if (ndb_builder_find_str(builder, (const char*)id, 32, pstr)) {
	//	pstr->packed.flag = NDB_PACKED_ID;
	//	return 1;
	//}

	if (ndb_builder_push_str(builder, (const char*)id, 32, pstr)) {
		pstr->packed.flag = NDB_PACKED_ID;
		return 1;
	}

	return 0;
}

union ndb_packed_str ndb_chars_to_packed_str(char c1, char c2)
{
	union ndb_packed_str str;
	str.packed.flag = NDB_PACKED_STR;
	str.packed.str[0] = c1;
	str.packed.str[1] = c2;
	str.packed.str[2] = '\0';
	return str;
}

static union ndb_packed_str ndb_char_to_packed_str(char c)
{
	union ndb_packed_str str;
	str.packed.flag = NDB_PACKED_STR;
	str.packed.str[0] = c;
	str.packed.str[1] = '\0';
	return str;
}


/// Check for small strings to pack
static inline int ndb_builder_try_compact_str(struct ndb_builder *builder,
					      const char *str, int len,
					      union ndb_packed_str *pstr,
					      int pack_ids)
{
	unsigned char id_buf[32];

	if (len == 0) {
		*pstr = ndb_char_to_packed_str(0);
		return 1;
	} else if (len == 1) {
		*pstr = ndb_char_to_packed_str(str[0]);
		return 1;
	} else if (len == 2) {
		*pstr = ndb_chars_to_packed_str(str[0], str[1]);
		return 1;
	} else if (pack_ids && len == 64 && hex_decode(str, 64, id_buf, 32)) {
		return ndb_builder_push_packed_id(builder, id_buf, pstr);
	}

	return 0;
}


static int ndb_builder_push_unpacked_str(struct ndb_builder *builder,
					 const char *str, int len,
					 union ndb_packed_str *pstr)
{
	if (ndb_builder_find_str(builder, str, len, pstr))
		return 1;

	return ndb_builder_push_str(builder, str, len, pstr);
}

int ndb_builder_make_str(struct ndb_builder *builder, const char *str, int len,
			 union ndb_packed_str *pstr, int pack_ids)
{
	if (ndb_builder_try_compact_str(builder, str, len, pstr, pack_ids))
		return 1;

	return ndb_builder_push_unpacked_str(builder, str, len, pstr);
}

int ndb_builder_set_content(struct ndb_builder *builder, const char *content,
			    int len)
{
	int pack_ids = 0;
	builder->note->content_length = len;
	return ndb_builder_make_str(builder, content, len,
				    &builder->note->content, pack_ids);
}


static inline int jsoneq(const char *json, jsmntok_t *tok, int tok_len,
			 const char *s)
{
	if (tok->type == JSMN_STRING && (int)strlen(s) == tok_len &&
	    memcmp(json + tok->start, s, tok_len) == 0) {
		return 1;
	}
	return 0;
}

static int ndb_builder_finalize_tag(struct ndb_builder *builder,
				    union ndb_packed_str offset)
{
	if (!cursor_push_u32(&builder->note_cur, offset.offset))
		return 0;
	builder->current_tag->count++;
	return 1;
}

/// Unescape and push json strings
static int ndb_builder_make_json_str(struct ndb_builder *builder,
				     const char *str, int len,
				     union ndb_packed_str *pstr,
				     int *written, int pack_ids)
{
	// let's not care about de-duping these. we should just unescape
	// in-place directly into the strings table.
	if (written)
		*written = len;

	const char *p, *end, *start;
	unsigned char *builder_start;

	// always try compact strings first
	if (ndb_builder_try_compact_str(builder, str, len, pstr, pack_ids))
		return 1;

	end = str + len;
	start = str; // Initialize start to the beginning of the string

	*pstr = ndb_offset_str(builder->strings.p - builder->strings.start);
	builder_start = builder->strings.p;

	for (p = str; p < end; p++) {
		if (*p == '\\' && p+1 < end) {
			// Push the chunk of unescaped characters before this escape sequence
			if (start < p && !cursor_push(&builder->strings,
						(unsigned char *)start,
						p - start)) {
				return 0;
			}

			if (!cursor_push_unescaped_char(&builder->strings, *p, *(p+1)))
				return 0;

			p++; // Skip the character following the backslash
			start = p + 1; // Update the start pointer to the next character
		}
	}

	// Handle the last chunk after the last escape sequence (or if there are no escape sequences at all)
	if (start < p && !cursor_push(&builder->strings, (unsigned char *)start,
				      p - start)) {
		return 0;
	}

	if (written)
		*written = builder->strings.p - builder_start;

	// TODO: dedupe these!?
	return cursor_push_byte(&builder->strings, '\0');
}

static int ndb_builder_push_json_tag(struct ndb_builder *builder,
				     const char *str, int len)
{
	union ndb_packed_str pstr;
	int pack_ids = 1;
	if (!ndb_builder_make_json_str(builder, str, len, &pstr, NULL, pack_ids))
		return 0;
	return ndb_builder_finalize_tag(builder, pstr);
}

// Push a json array into an ndb tag ["p", "abcd..."] -> struct ndb_tag
static int ndb_builder_tag_from_json_array(struct ndb_json_parser *p,
					   jsmntok_t *array)
{
	jsmntok_t *str_tok;
	const char *str;

	if (array->size == 0)
		return 0;

	if (!ndb_builder_new_tag(&p->builder))
		return 0;

	for (int i = 0; i < array->size; i++) {
		str_tok = &array[i+1];
		str = p->json + str_tok->start;

		if (!ndb_builder_push_json_tag(&p->builder, str,
					       toksize(str_tok))) {
			return 0;
		}
	}

	return 1;
}

// Push json tags into ndb data
//   [["t", "hashtag"], ["p", "abcde..."]] -> struct ndb_tags
static inline int ndb_builder_process_json_tags(struct ndb_json_parser *p,
						jsmntok_t *array)
{
	jsmntok_t *tag = array;

	if (array->size == 0)
		return 1;

	for (int i = 0; i < array->size; i++) {
		if (!ndb_builder_tag_from_json_array(p, &tag[i+1]))
			return 0;
		tag += tag[i+1].size;
	}

	return 1;
}

static int parse_unsigned_int(const char *start, int len, unsigned int *num)
{
	unsigned int number = 0;
	const char *p = start, *end = start + len;
	int digits = 0;

	while (p < end) {
		char c = *p;

		if (c < '0' || c > '9')
			break;

		// Check for overflow
		char digit = c - '0';
		if (number > (UINT_MAX - digit) / 10)
			return 0; // Overflow detected

		number = number * 10 + digit;

		p++;
		digits++;
	}

	if (digits == 0)
		return 0;

	*num = number;
	return 1;
}

int ndb_client_event_from_json(const char *json, int len, struct ndb_fce *fce,
			       unsigned char *buf, int bufsize, struct ndb_id_cb *cb)
{
	jsmntok_t *tok = NULL;
	int tok_len, res;
	struct ndb_json_parser parser;
	struct ndb_event *ev = &fce->event;

	ndb_json_parser_init(&parser, json, len, buf, bufsize);

	if ((res = ndb_json_parser_parse(&parser, cb)) < 0)
		return res;

	if (parser.toks[0].type == JSMN_OBJECT) {
		ndb_debug("got raw json in client_event_from_json\n");
		fce->evtype = NDB_FCE_EVENT;
		return ndb_parse_json_note(&parser, &ev->note);
	}

	if (parser.num_tokens <= 3 || parser.toks[0].type != JSMN_ARRAY)
		return 0;

	parser.i = 1;
	tok = &parser.toks[parser.i++];
	tok_len = toksize(tok);
	if (tok->type != JSMN_STRING)
		return 0;

	if (tok_len == 5 && !memcmp("EVENT", json + tok->start, 5)) {
		fce->evtype = NDB_FCE_EVENT;
		return ndb_parse_json_note(&parser, &ev->note);
	}

	return 0;
}


int ndb_ws_event_from_json(const char *json, int len, struct ndb_tce *tce,
			   unsigned char *buf, int bufsize,
			   struct ndb_id_cb *cb)
{
	jsmntok_t *tok = NULL;
	int tok_len, res;
	struct ndb_json_parser parser;
	struct ndb_event *ev = &tce->event;

	tce->subid_len = 0;
	tce->subid = "";

	ndb_json_parser_init(&parser, json, len, buf, bufsize);

	if ((res = ndb_json_parser_parse(&parser, cb)) < 0)
		return res;

	if (parser.toks[0].type == JSMN_OBJECT) {
		ndb_debug("got raw json in ws_event_from_json\n");
		tce->evtype = NDB_TCE_EVENT;
		return ndb_parse_json_note(&parser, &ev->note);
	}

	if (parser.num_tokens < 3 || parser.toks[0].type != JSMN_ARRAY)
		return 0;

	parser.i = 1;
	tok = &parser.toks[parser.i++];
	tok_len = toksize(tok);
	if (tok->type != JSMN_STRING)
		return 0;

	if (tok_len == 5 && !memcmp("EVENT", json + tok->start, 5)) {
		tce->evtype = NDB_TCE_EVENT;

		tok = &parser.toks[parser.i++];
		if (tok->type != JSMN_STRING)
			return 0;

		tce->subid = json + tok->start;
		tce->subid_len = toksize(tok);

		return ndb_parse_json_note(&parser, &ev->note);
	} else if (tok_len == 4 && !memcmp("EOSE", json + tok->start, 4)) {
		tce->evtype = NDB_TCE_EOSE;

		tok = &parser.toks[parser.i++];
		if (tok->type != JSMN_STRING)
			return 0;

		tce->subid = json + tok->start;
		tce->subid_len = toksize(tok);
		return 1;
	} else if (tok_len == 2 && !memcmp("OK", json + tok->start, 2)) {
		if (parser.num_tokens != 5)
			return 0;

		struct ndb_command_result *cr = &tce->command_result;

		tce->evtype = NDB_TCE_OK;

		tok = &parser.toks[parser.i++];
		if (tok->type != JSMN_STRING)
			return 0;

		tce->subid = json + tok->start;
		tce->subid_len = toksize(tok);

		tok = &parser.toks[parser.i++];
		if (tok->type != JSMN_PRIMITIVE || toksize(tok) == 0)
			return 0;

		cr->ok = (json + tok->start)[0] == 't';

		tok = &parser.toks[parser.i++];
		if (tok->type != JSMN_STRING)
			return 0;

		tce->command_result.msg = json + tok->start;
		tce->command_result.msglen = toksize(tok);

		return 1;
	} else if (tok_len == 4 && !memcmp("AUTH", json + tok->start, 4)) {
		tce->evtype = NDB_TCE_AUTH;

		tok = &parser.toks[parser.i++];
		if (tok->type != JSMN_STRING)
			return 0;

		tce->subid = json + tok->start;
		tce->subid_len = toksize(tok);

		return 1;
	}

	return 0;
}

static enum ndb_filter_fieldtype
ndb_filter_parse_field(const char *tok, int len, char *tagchar)
{
	*tagchar = 0;

	if (len == 0)
		return 0;

	if (len == 7 && !strncmp(tok, "authors", 7)) {
		return NDB_FILTER_AUTHORS;
	} else if (len == 3 && !strncmp(tok, "ids", 3)) {
		return NDB_FILTER_IDS;
	} else if (len == 5 && !strncmp(tok, "kinds", 5)) {
		return NDB_FILTER_KINDS;
	} else if (len == 2 && tok[0] == '#') {
		*tagchar = tok[1];
		return NDB_FILTER_TAGS;
	} else if (len == 5 && !strncmp(tok, "since", 5)) {
		return NDB_FILTER_SINCE;
	} else if (len == 5 && !strncmp(tok, "until", 5)) {
		return NDB_FILTER_UNTIL;
	} else if (len == 5 && !strncmp(tok, "limit", 5)) {
		return NDB_FILTER_LIMIT;
	}

	return 0;
}

static int ndb_filter_parse_json_ids(struct ndb_json_parser *parser,
				     struct ndb_filter *filter)
{
	jsmntok_t *tok;
	const char *start;
	unsigned char hexbuf[32];
	int tok_len, i, size;

	tok = &parser->toks[parser->i++];

	if (tok->type != JSMN_ARRAY) {
		ndb_debug("parse_json_ids: not an array\n");
		return 0;
	}

	size = tok->size;

	for (i = 0; i < size; parser->i++, i++) {
		tok = &parser->toks[parser->i];
		start = parser->json + tok->start;
		tok_len = toksize(tok);

		if (tok->type != JSMN_STRING) {
			ndb_debug("parse_json_ids: not a string '%d'\n", tok->type);
			return 0;
		}

		if (tok_len != 64) {
			ndb_debug("parse_json_ids: not len 64: '%.*s'\n", tok_len, start);
			return 0;
		}

		// id
		if (!hex_decode(start, tok_len, hexbuf, sizeof(hexbuf))) {
			ndb_debug("parse_json_ids: hex decode failed\n");
			return 0;
		}

		ndb_debug("adding id elem\n");
		if (!ndb_filter_add_id_element(filter, hexbuf)) {
			ndb_debug("parse_json_ids: failed to add id element\n");
			return 0;
		}
	}

	parser->i--;
	return 1;
}

static int ndb_filter_parse_json_elems(struct ndb_json_parser *parser,
				       struct ndb_filter *filter)
{
	jsmntok_t *tok;
	const char *start;
	int tok_len;
	unsigned char hexbuf[32];
	enum ndb_generic_element_type typ;
	tok = NULL;
	int i, size;

	tok = &parser->toks[parser->i++];

	if (tok->type != JSMN_ARRAY)
		return 0;

	size = tok->size;

	for (i = 0; i < size; i++, parser->i++) {
		tok = &parser->toks[parser->i];
		start = parser->json + tok->start;
		tok_len = toksize(tok);

		if (tok->type != JSMN_STRING)
			return 0;

		if (i == 0) {
			if (tok_len == 64 && hex_decode(start, 64, hexbuf, sizeof(hexbuf))) {
				typ = NDB_ELEMENT_ID;
				if (!ndb_filter_add_id_element(filter, hexbuf)) {
					ndb_debug("failed to push id elem\n");
					return 0;
				}
			} else {
				typ = NDB_ELEMENT_STRING;
				if (!ndb_filter_add_str_element_len(filter, start, tok_len))
					return 0;
			}
		} else if (typ == NDB_ELEMENT_ID) {
			if (!hex_decode(start, 64, hexbuf, sizeof(hexbuf)))
				return 0;
			if (!ndb_filter_add_id_element(filter, hexbuf))
				return 0;
		} else if (typ == NDB_ELEMENT_STRING) {
			if (!ndb_filter_add_str_element_len(filter, start, tok_len))
				return 0;
		} else {
			// ???
			return 0;
		}
	}

	parser->i--;
	return 1;
}

static int ndb_filter_parse_json_int(struct ndb_json_parser *parser,
				     struct ndb_filter *filter)
{
	jsmntok_t *tok;
	const char *start;
	int tok_len;
	unsigned int value;

	tok = &parser->toks[parser->i];
	start = parser->json + tok->start;
	tok_len = toksize(tok);

	if (tok->type != JSMN_PRIMITIVE)
		return 0;

	if (!parse_unsigned_int(start, tok_len, &value))
		return 0;

	if (!ndb_filter_add_int_element(filter, (uint64_t)value))
		return 0;

	ndb_debug("added int elem %d\n", value);

	return 1;
}


static int ndb_filter_parse_json_ints(struct ndb_json_parser *parser,
				      struct ndb_filter *filter)
{
	jsmntok_t *tok;
	int size, i;

	tok = &parser->toks[parser->i++];

	if (tok->type != JSMN_ARRAY)
		return 0;

	size = tok->size;

	for (i = 0; i < size; parser->i++, i++) {
		if (!ndb_filter_parse_json_int(parser, filter))
			return 0;
	}

	parser->i--;
	return 1;
}


static int ndb_filter_parse_json(struct ndb_json_parser *parser,
				 struct ndb_filter *filter)
{
	jsmntok_t *tok = NULL;
	const char *json = parser->json;
	const char *start;
	char tag;
	int tok_len;
	enum ndb_filter_fieldtype field;

	if (parser->toks[parser->i++].type != JSMN_OBJECT)
		return 0;

	for (; parser->i < parser->num_tokens; parser->i++) {
		tok = &parser->toks[parser->i++];
		start = json + tok->start;
		tok_len = toksize(tok);

		if (!(field = ndb_filter_parse_field(start, tok_len, &tag))) {
			ndb_debug("failed field '%.*s'\n", tok_len, start);
			continue;
		}

		if (tag) {
			ndb_debug("starting tag field '%c'\n", tag);
			if (!ndb_filter_start_tag_field(filter, tag)) {
				ndb_debug("failed to start tag field '%c'\n", tag);
				return 0;
			}
		} else if (!ndb_filter_start_field(filter, field)) {
			ndb_debug("field already started\n");
			return 0;
		}

		// we parsed a top-level field
		switch(field) {
		case NDB_FILTER_AUTHORS:
		case NDB_FILTER_IDS:
			if (!ndb_filter_parse_json_ids(parser, filter)) {
				ndb_debug("failed to parse filter ids/authors\n");
				return 0;
			}
			break;
		case NDB_FILTER_SINCE:
		case NDB_FILTER_UNTIL:
		case NDB_FILTER_LIMIT:
			if (!ndb_filter_parse_json_int(parser, filter)) {
				ndb_debug("failed to parse filter since/until/limit\n");
				return 0;
			}
			break;
		case NDB_FILTER_KINDS:
			if (!ndb_filter_parse_json_ints(parser, filter)) {
				ndb_debug("failed to parse filter kinds\n");
				return 0;
			}
			break;
		case NDB_FILTER_TAGS:
			if (!ndb_filter_parse_json_elems(parser, filter)) {
				ndb_debug("failed to parse filter tags\n");
				return 0;
			}
			break;
		}

		ndb_filter_end_field(filter);
	}

	return ndb_filter_end(filter);
}

int ndb_parse_json_note(struct ndb_json_parser *parser, struct ndb_note **note)
{
	jsmntok_t *tok = NULL;
	unsigned char hexbuf[64];
	const char *json = parser->json;
	const char *start;
	int i, tok_len, parsed;

	parsed = 0;

	if (parser->toks[parser->i].type != JSMN_OBJECT)
		return 0;

	// TODO: build id buffer and verify at end

	for (i = parser->i + 1; i < parser->num_tokens; i++) {
		tok = &parser->toks[i];
		start = json + tok->start;
		tok_len = toksize(tok);

		//printf("toplevel %.*s %d\n", tok_len, json + tok->start, tok->type);
		if (tok_len == 0 || i + 1 >= parser->num_tokens)
			continue;

		if (start[0] == 'p' && jsoneq(json, tok, tok_len, "pubkey")) {
			// pubkey
			tok = &parser->toks[i+1];
			hex_decode(json + tok->start, toksize(tok), hexbuf, sizeof(hexbuf));
			parsed |= NDB_PARSED_PUBKEY;
			ndb_builder_set_pubkey(&parser->builder, hexbuf);
		} else if (tok_len == 2 && start[0] == 'i' && start[1] == 'd') {
			// id
			tok = &parser->toks[i+1];
			hex_decode(json + tok->start, toksize(tok), hexbuf, sizeof(hexbuf));
			parsed |= NDB_PARSED_ID;
			ndb_builder_set_id(&parser->builder, hexbuf);
		} else if (tok_len == 3 && start[0] == 's' && start[1] == 'i' && start[2] == 'g') {
			// sig
			tok = &parser->toks[i+1];
			hex_decode(json + tok->start, toksize(tok), hexbuf, sizeof(hexbuf));
			parsed |= NDB_PARSED_SIG;
			ndb_builder_set_sig(&parser->builder, hexbuf);
		} else if (start[0] == 'k' && jsoneq(json, tok, tok_len, "kind")) {
			// kind
			tok = &parser->toks[i+1];
			start = json + tok->start;
			if (tok->type != JSMN_PRIMITIVE || tok_len <= 0)
				return 0;
			if (!parse_unsigned_int(start, toksize(tok),
						&parser->builder.note->kind))
					return 0;
			parsed |= NDB_PARSED_KIND;
		} else if (start[0] == 'c') {
			if (jsoneq(json, tok, tok_len, "created_at")) {
				// created_at
				tok = &parser->toks[i+1];
				start = json + tok->start;
				if (tok->type != JSMN_PRIMITIVE || tok_len <= 0)
					return 0;
				// TODO: update to int64 in 2106 ... xD
				unsigned int bigi;
				if (!parse_unsigned_int(start, toksize(tok), &bigi))
					return 0;
				parser->builder.note->created_at = bigi;
				parsed |= NDB_PARSED_CREATED_AT;
			} else if (jsoneq(json, tok, tok_len, "content")) {
				// content
				tok = &parser->toks[i+1];
				union ndb_packed_str pstr;
				tok_len = toksize(tok);
				int written, pack_ids = 0;
				if (!ndb_builder_make_json_str(&parser->builder,
							json + tok->start,
							tok_len, &pstr,
							&written, pack_ids)) {
					ndb_debug("ndb_builder_make_json_str failed\n");
					return 0;
				}
				parser->builder.note->content_length = written;
				parser->builder.note->content = pstr;
				parsed |= NDB_PARSED_CONTENT;
			}
		} else if (start[0] == 't' && jsoneq(json, tok, tok_len, "tags")) {
			tok = &parser->toks[i+1];
			ndb_builder_process_json_tags(parser, tok);
			i += tok->size;
			parsed |= NDB_PARSED_TAGS;
		}
	}

	//ndb_debug("parsed %d = %d, &->%d", parsed, NDB_PARSED_ALL, parsed & NDB_PARSED_ALL);
	if (parsed != NDB_PARSED_ALL)
		return 0;

	return ndb_builder_finalize(&parser->builder, note, NULL);
}

int ndb_filter_from_json(const char *json, int len, struct ndb_filter *filter,
			 unsigned char *buf, int bufsize)
{
	struct ndb_json_parser parser;
	int res;

	if (filter->finalized)
		return 0;

	ndb_json_parser_init(&parser, json, len, buf, bufsize);
	if ((res = ndb_json_parser_parse(&parser, NULL)) < 0)
		return res;

	if (parser.num_tokens < 1)
		return 0;

	return ndb_filter_parse_json(&parser, filter);
}

int ndb_note_from_json(const char *json, int len, struct ndb_note **note,
		       unsigned char *buf, int bufsize)
{
	struct ndb_json_parser parser;
	int res;

	ndb_json_parser_init(&parser, json, len, buf, bufsize);
	if ((res = ndb_json_parser_parse(&parser, NULL)) < 0)
		return res;

	if (parser.num_tokens < 1)
		return 0;

	return ndb_parse_json_note(&parser, note);
}

void ndb_builder_set_pubkey(struct ndb_builder *builder, unsigned char *pubkey)
{
	memcpy(builder->note->pubkey, pubkey, 32);
}

void ndb_builder_set_id(struct ndb_builder *builder, unsigned char *id)
{
	memcpy(builder->note->id, id, 32);
}

void ndb_builder_set_sig(struct ndb_builder *builder, unsigned char *sig)
{
	memcpy(builder->note->sig, sig, 64);
}

void ndb_builder_set_kind(struct ndb_builder *builder, uint32_t kind)
{
	builder->note->kind = kind;
}

void ndb_builder_set_created_at(struct ndb_builder *builder, uint64_t created_at)
{
	builder->note->created_at = created_at;
}

int ndb_builder_new_tag(struct ndb_builder *builder)
{
	builder->note->tags.count++;
	struct ndb_tag tag = {0};
	builder->current_tag = (struct ndb_tag *)builder->note_cur.p;
	return cursor_push_tag(&builder->note_cur, &tag);
}

void ndb_stat_counts_init(struct ndb_stat_counts *counts)
{
	counts->count = 0;
	counts->key_size = 0;
	counts->value_size = 0;
}

static void ndb_stat_init(struct ndb_stat *stat)
{
	// init stats
	int i;

	for (i = 0; i < NDB_CKIND_COUNT; i++) {
		ndb_stat_counts_init(&stat->common_kinds[i]);
	}

	for (i = 0; i < NDB_DBS; i++) {
		ndb_stat_counts_init(&stat->dbs[i]);
	}

	ndb_stat_counts_init(&stat->other_kinds);
}

int ndb_stat(struct ndb *ndb, struct ndb_stat *stat)
{
	int rc;
	MDB_cursor *cur;
	MDB_val k, v;
	MDB_dbi db;
	struct ndb_txn txn;
	struct ndb_note *note;
	int i;
	enum ndb_common_kind common_kind;

	// initialize to 0
	ndb_stat_init(stat);

	if (!ndb_begin_query(ndb, &txn)) {
		fprintf(stderr, "ndb_stat failed at ndb_begin_query\n");
		return 0;
	}

	// stat each dbi in the database
	for (i = 0; i < NDB_DBS; i++)
	{
		db = ndb->lmdb.dbs[i];

		if ((rc = mdb_cursor_open(txn.mdb_txn, db, &cur))) {
			fprintf(stderr, "ndb_stat: mdb_cursor_open failed, error '%s'\n",
					mdb_strerror(rc));
			return 0;
		}

		// loop over every entry and count kv sizes
		while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
			// we gather more detailed per-kind stats if we're in
			// the notes db
			if (i == NDB_DB_NOTE) {
				note = v.mv_data;
				common_kind = ndb_kind_to_common_kind(note->kind);

				// uncommon kind? just count them in bulk
				if ((int)common_kind == -1) {
					stat->other_kinds.count++;
					stat->other_kinds.key_size += k.mv_size;
					stat->other_kinds.value_size += v.mv_size;
				} else {
					stat->common_kinds[common_kind].count++;
					stat->common_kinds[common_kind].key_size += k.mv_size;
					stat->common_kinds[common_kind].value_size += v.mv_size;
				}
			}

			stat->dbs[i].count++;
			stat->dbs[i].key_size += k.mv_size;
			stat->dbs[i].value_size += v.mv_size;
		}

		// close the cursor, they are per-dbi
		mdb_cursor_close(cur);
	}

	ndb_end_query(&txn);

	return 1;
}

/// Push an element to the current tag
///
/// Basic idea is to call ndb_builder_new_tag
int ndb_builder_push_tag_str(struct ndb_builder *builder,
				    const char *str, int len)
{
	union ndb_packed_str pstr;
	int pack_ids = 1;
	if (!ndb_builder_make_str(builder, str, len, &pstr, pack_ids))
		return 0;
	return ndb_builder_finalize_tag(builder, pstr);
}

//
// CONFIG
//
void ndb_default_config(struct ndb_config *config)
{
	int cores = get_cpu_cores();
	config->mapsize = 1024UL * 1024UL * 1024UL * 32UL; // 32 GiB
	config->ingester_threads = cores == -1 ? 4 : cores;
	config->flags = 0;
	config->ingest_filter = NULL;
	config->filter_context = NULL;
	config->sub_cb_ctx = NULL;
	config->sub_cb = NULL;
}

void ndb_config_set_subscription_callback(struct ndb_config *config, ndb_sub_fn fn, void *context)
{
	config->sub_cb_ctx = context;
	config->sub_cb = fn;
}

void ndb_config_set_ingest_threads(struct ndb_config *config, int threads)
{
	config->ingester_threads = threads;
}

void ndb_config_set_flags(struct ndb_config *config, int flags)
{
	config->flags = flags;
}

void ndb_config_set_mapsize(struct ndb_config *config, size_t mapsize)
{
	config->mapsize = mapsize;
}

void ndb_config_set_ingest_filter(struct ndb_config *config,
				  ndb_ingest_filter_fn fn, void *filter_ctx)
{
	config->ingest_filter = fn;
	config->filter_context = filter_ctx;
}

int ndb_print_tag_index(struct ndb_txn *txn)
{
	MDB_cursor *cur;
	MDB_val k, v;
	int i;

	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_TAGS], &cur))
		return 0;

	i = 1;
	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
		printf("%d ", i);
		print_tag_kv(txn, &k, &v);
		i++;
	}

	return 1;
}

int ndb_print_kind_keys(struct ndb_txn *txn)
{
	MDB_cursor *cur;
	MDB_val k, v;
	int i;
	struct ndb_u64_ts *tsid;

	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_KIND], &cur))
		return 0;

	i = 1;
	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
		tsid = k.mv_data;
		printf("%d note_kind %" PRIu64 " %" PRIu64 "\n",
			i, tsid->u64, tsid->timestamp);

		i++;
	}

	return 1;
}

// used by ndb.c
int ndb_print_search_keys(struct ndb_txn *txn)
{
	MDB_cursor *cur;
	MDB_val k, v;
	int i;
	struct ndb_text_search_key search_key;

	if (mdb_cursor_open(txn->mdb_txn, txn->lmdb->dbs[NDB_DB_NOTE_TEXT], &cur))
		return 0;

	i = 1;
	while (mdb_cursor_get(cur, &k, &v, MDB_NEXT) == 0) {
		if (!ndb_unpack_text_search_key(k.mv_data, k.mv_size, &search_key)) {
			fprintf(stderr, "error decoding key %d\n", i);
			continue;
		}

		ndb_print_text_search_key(&search_key);
		printf("\n");

		i++;
	}

	return 1;
}

struct ndb_tags *ndb_note_tags(struct ndb_note *note)
{
	return &note->tags;
}

struct ndb_str ndb_note_str(struct ndb_note *note, union ndb_packed_str *pstr)
{
	struct ndb_str str;
	str.flag = pstr->packed.flag;

	if (str.flag == NDB_PACKED_STR) {
		str.str = pstr->packed.str;
		return str;
	}

	str.str = ((const char *)note) + note->strings + (pstr->offset & 0xFFFFFF);
	return str;
}

struct ndb_str ndb_tag_str(struct ndb_note *note, struct ndb_tag *tag, int ind)
{
	return ndb_note_str(note, &tag->strs[ind]);
}

int ndb_str_len(struct ndb_str *str)
{
	if (str->flag == NDB_PACKED_ID)
		return 32;
	return strlen(str->str);
}

struct ndb_str ndb_iter_tag_str(struct ndb_iterator *iter, int ind)
{
	return ndb_tag_str(iter->note, iter->tag, ind);
}

unsigned char * ndb_note_id(struct ndb_note *note)
{
	return note->id;
}

unsigned char * ndb_note_pubkey(struct ndb_note *note)
{
	return note->pubkey;
}

unsigned char * ndb_note_sig(struct ndb_note *note)
{
	return note->sig;
}

uint32_t ndb_note_created_at(struct ndb_note *note)
{
	return note->created_at;
}

uint32_t ndb_note_kind(struct ndb_note *note)
{
	return note->kind;
}

void _ndb_note_set_kind(struct ndb_note *note, uint32_t kind)
{
	note->kind = kind;
}

const char *ndb_note_content(struct ndb_note *note)
{
	return ndb_note_str(note, &note->content).str;
}

uint32_t ndb_note_content_length(struct ndb_note *note)
{
	return note->content_length;
}

struct ndb_note * ndb_note_from_bytes(unsigned char *bytes)
{
	struct ndb_note *note = (struct ndb_note *)bytes;
	if (note->version != 1)
		return 0;
	return note;
}

void ndb_tags_iterate_start(struct ndb_note *note, struct ndb_iterator *iter)
{
	iter->note = note;
	iter->tag = NULL;
	iter->index = -1;
}

// Helper function to get a pointer to the nth tag
static struct ndb_tag *ndb_tags_tag(struct ndb_tags *tags, size_t index) {
    return (struct ndb_tag *)((uint8_t *)tags + sizeof(struct ndb_tags) + index * sizeof(struct ndb_tag));
}

int ndb_tags_iterate_next(struct ndb_iterator *iter)
{
	struct ndb_tags *tags;

	if (iter->tag == NULL || iter->index == -1) {
		iter->tag = ndb_tags_tag(&iter->note->tags, 0);
		iter->index = 0;
		return iter->note->tags.count != 0;
	}

	tags = &iter->note->tags;

	if (++iter->index < tags->count) {
		uint32_t tag_data_size = iter->tag->count * sizeof(iter->tag->strs[0]);
		iter->tag = (struct ndb_tag *)(iter->tag->strs[0].bytes + tag_data_size);
		return 1;
	}

	return 0;
}

uint16_t ndb_tags_count(struct ndb_tags *tags)
{
	return tags->count;
}

uint16_t ndb_tag_count(struct ndb_tag *tags)
{
	return tags->count;
}

enum ndb_common_kind ndb_kind_to_common_kind(int kind)
{
	switch (kind)
	{
		case 0:     return NDB_CKIND_PROFILE;
		case 1:     return NDB_CKIND_TEXT;
		case 3:     return NDB_CKIND_CONTACTS;
		case 4:     return NDB_CKIND_DM;
		case 5:     return NDB_CKIND_DELETE;
		case 6:     return NDB_CKIND_REPOST;
		case 7:     return NDB_CKIND_REACTION;
		case 9735:  return NDB_CKIND_ZAP;
		case 9734:  return NDB_CKIND_ZAP_REQUEST;
		case 23194: return NDB_CKIND_NWC_REQUEST;
		case 23195: return NDB_CKIND_NWC_RESPONSE;
		case 27235: return NDB_CKIND_HTTP_AUTH;
		case 30000: return NDB_CKIND_LIST;
		case 30023: return NDB_CKIND_LONGFORM;
		case 30315: return NDB_CKIND_STATUS;
	}

	return -1;
}

const char *ndb_kind_name(enum ndb_common_kind ck)
{
	switch (ck) {
		case NDB_CKIND_PROFILE:      return "profile";
		case NDB_CKIND_TEXT:         return "text";
		case NDB_CKIND_CONTACTS:     return "contacts";
		case NDB_CKIND_DM:           return "dm";
		case NDB_CKIND_DELETE:       return "delete";
		case NDB_CKIND_REPOST:       return "repost";
		case NDB_CKIND_REACTION:     return "reaction";
		case NDB_CKIND_ZAP:          return "zap";
		case NDB_CKIND_ZAP_REQUEST:  return "zap_request";
		case NDB_CKIND_NWC_REQUEST:  return "nwc_request";
		case NDB_CKIND_NWC_RESPONSE: return "nwc_response";
		case NDB_CKIND_HTTP_AUTH:    return "http_auth";
		case NDB_CKIND_LIST:         return "list";
		case NDB_CKIND_LONGFORM:     return "longform";
		case NDB_CKIND_STATUS:       return "status";
		case NDB_CKIND_COUNT:        return "unknown";
	}

	return "unknown";
}

const char *ndb_db_name(enum ndb_dbs db)
{
	switch (db) {
		case NDB_DB_NOTE:
			return "note";
		case NDB_DB_META:
			return "note_metadata";
		case NDB_DB_PROFILE:
			return "profile";
		case NDB_DB_NOTE_ID:
			return "note_index";
		case NDB_DB_PROFILE_PK:
			return "profile_pubkey_index";
		case NDB_DB_NDB_META:
			return "nostrdb_metadata";
		case NDB_DB_PROFILE_SEARCH:
			return "profile_search";
		case NDB_DB_PROFILE_LAST_FETCH:
			return "profile_last_fetch";
		case NDB_DB_NOTE_KIND:
			return "note_kind_index";
		case NDB_DB_NOTE_TEXT:
			return "note_fulltext";
		case NDB_DB_NOTE_BLOCKS:
			return "note_blocks";
		case NDB_DB_NOTE_TAGS:
			return "note_tags";
		case NDB_DBS:
			return "count";
	}

	return "unknown";
}

static struct ndb_blocks *ndb_note_to_blocks(struct ndb_note *note)
{
	const char *content;
	size_t content_len;
	struct ndb_blocks *blocks;

	content = ndb_note_content(note);
	content_len = ndb_note_content_length(note);

	// something weird is going on
	if (content_len >= INT32_MAX)
		return NULL;

	unsigned char *buffer = malloc(content_len);
	if (!buffer)
		return NULL;

	if (!ndb_parse_content(buffer, content_len, content, content_len, &blocks)) {
		free(buffer);
		return NULL;
	}

	//blocks = realloc(blocks, ndb_blocks_total_size(blocks));
	//if (blocks == NULL)
		//return NULL;

	blocks->flags |= NDB_BLOCK_FLAG_OWNED;

	return blocks;
}

struct ndb_blocks *ndb_get_blocks_by_key(struct ndb *ndb, struct ndb_txn *txn, uint64_t note_key)
{
	struct ndb_blocks *blocks, *blocks_to_writer;
	size_t blocks_size;
	struct ndb_note *note;
	size_t note_len;

	if ((blocks = ndb_lookup_by_key(txn, note_key, NDB_DB_NOTE_BLOCKS, &note_len))) {
		return blocks;
	}

	// If we don't have note blocks, let's lazily generate them. This is
	// migration-friendly instead of doing them all at once
	if (!(note = ndb_get_note_by_key(txn, note_key, &note_len))) {
		// no note found, can't return note blocks
		return NULL;
	}

	 if (!(blocks = ndb_note_to_blocks(note)))
		 return NULL;

	 // send a copy to the writer
	 blocks_size = ndb_blocks_total_size(blocks);
	 blocks_to_writer = malloc(blocks_size);
	 memcpy(blocks_to_writer, blocks, blocks_size);
	 assert(blocks->flags & NDB_BLOCK_FLAG_OWNED);

	 // we generated new blocks, let's store them in the DB
	 struct ndb_writer_blocks write_blocks = {
		 .blocks = blocks_to_writer,
		 .note_key = note_key
	 };

	 assert(write_blocks.blocks != blocks);

	 struct ndb_writer_msg msg = { .type = NDB_WRITER_BLOCKS };
	 msg.blocks = write_blocks;

	 ndb_writer_queue_msg(&ndb->writer, &msg);

	 return blocks;
}

// please call ndb_monitor_lock before calling this
static struct ndb_subscription *
ndb_monitor_find_subscription(struct ndb_monitor *monitor, uint64_t subid, int *index)
{
	struct ndb_subscription *sub, *tsub;
	int i;

	for (i = 0, sub = NULL; i < monitor->num_subscriptions; i++) {
		tsub = &monitor->subscriptions[i];
		if (tsub->subid == subid) {
			sub = tsub;
			if (index)
				*index = i;
			break;
		}
	}

	return sub;
}

int ndb_poll_for_notes(struct ndb *ndb, uint64_t subid, uint64_t *note_ids,
		       int note_id_capacity)
{
	struct ndb_subscription *sub;
	int res;

	if (subid == 0)
		return 0;

	ndb_monitor_lock(&ndb->monitor);

	if (!(sub = ndb_monitor_find_subscription(&ndb->monitor, subid, NULL)))
		res = 0;
	else
		res = prot_queue_try_pop_all(&sub->inbox, note_ids, note_id_capacity);

	ndb_monitor_unlock(&ndb->monitor);

	return res;
}

int ndb_wait_for_notes(struct ndb *ndb, uint64_t subid, uint64_t *note_ids,
                       int note_id_capacity)
{
	struct ndb_subscription *sub;
	struct prot_queue *queue_inbox;

        // this is not a valid subscription id
	if (subid == 0)
		return 0;

	ndb_monitor_lock(&ndb->monitor);

        if (!(sub = ndb_monitor_find_subscription(&ndb->monitor, subid, NULL))) {
		ndb_monitor_unlock(&ndb->monitor);
		return 0;
	}

	queue_inbox = &sub->inbox;

	ndb_monitor_unlock(&ndb->monitor);

	// there is technically a race condition if the thread yeilds at this
	// comment and a subscription is added/removed. A deadlock in the
	// writer queue would be much worse though. This function is dubious
	// anyways.

        return prot_queue_pop_all(queue_inbox, note_ids, note_id_capacity);
}

int ndb_unsubscribe(struct ndb *ndb, uint64_t subid)
{
	struct ndb_subscription *sub;
	int index, res, elems_to_move;

	ndb_monitor_lock(&ndb->monitor);

	if (!(sub = ndb_monitor_find_subscription(&ndb->monitor, subid, &index))) {
		res = 0;
		goto done;
	}

	ndb_subscription_destroy(sub);

	elems_to_move = (--ndb->monitor.num_subscriptions) - index;

	memmove(&ndb->monitor.subscriptions[index],
		&ndb->monitor.subscriptions[index+1],
		elems_to_move * sizeof(*sub));

	res = 1;

done:
	ndb_monitor_unlock(&ndb->monitor);

	return res;
}

int ndb_num_subscriptions(struct ndb *ndb)
{
	return ndb->monitor.num_subscriptions;
}

uint64_t ndb_subscribe(struct ndb *ndb, struct ndb_filter *filters, int num_filters)
{
	static uint64_t subids = 0;
	struct ndb_subscription *sub;
	size_t buflen;
	uint64_t subid;
	char *buf;

	ndb_monitor_lock(&ndb->monitor);

	if (ndb->monitor.num_subscriptions + 1 >= MAX_SUBSCRIPTIONS) {
		fprintf(stderr, "too many subscriptions\n");
		subid = 0;
		goto done;
	}

	sub = &ndb->monitor.subscriptions[ndb->monitor.num_subscriptions];
	subid = ++subids;
	sub->subid = subid;

	ndb_filter_group_init(&sub->group);
	if (!ndb_filter_group_add_filters(&sub->group, filters, num_filters)) {
		subid = 0;
		goto done;
	}

	// 500k ought to be enough for anyone
	buflen = sizeof(uint64_t) * DEFAULT_QUEUE_SIZE;
	buf = malloc(buflen);

	if (!prot_queue_init(&sub->inbox, buf, buflen, sizeof(uint64_t))) {
		fprintf(stderr, "failed to push prot queue\n");
		subid = 0;
		goto done;
	}

	ndb->monitor.num_subscriptions++;
done:
	ndb_monitor_unlock(&ndb->monitor);

	return subid;
}