more mention progress

Signed-off-by: William Casarin <jb55@jb55.com>

damus/Models/Post.swift

@@ -0,0 +1,69 @@
+//
+//  Post.swift
+//  damus
+//
+//  Created by William Casarin on 2022-05-07.
+//
+
+import Foundation
+
+struct NostrPost {
+    let content: String
+    let references: [ReferencedId]
+}
+
+// TODO: parse nostr:{e,p}:pubkey uris as well
+func parse_post_mention_type(_ p: Parser) -> MentionType? {
+    if parse_char(p, "@") {
+        return .pubkey
+    }
+    
+    if parse_char(p, "&") {
+        return .event
+    }
+    
+    return nil
+}
+
+func parse_post_reference(_ p: Parser) -> ReferencedId? {
+    let start = p.pos
+    
+    guard let typ = parse_post_mention_type(p) else {
+        return parse_nostr_ref_uri(p)
+    }
+    
+    guard let id = parse_hexstr(p, len: 64) else {
+        p.pos = start
+        return nil
+    }
+    
+    return ReferencedId(ref_id: id, relay_id: nil, key: typ.ref)
+}
+
+
+/// Return a list of tags
+func parse_post_blocks(content: String) -> [PostBlock] {
+    let p = Parser(pos: 0, str: content)
+    var blocks: [PostBlock] = []
+    var starting_from: Int = 0
+    
+    if content.count == 0 {
+        return []
+    }
+    
+    while p.pos < content.count {
+        let pre_mention = p.pos
+        if let reference = parse_post_reference(p) {
+            blocks.append(parse_post_textblock(str: p.str, from: starting_from, to: pre_mention))
+            blocks.append(.ref(reference))
+            starting_from = p.pos
+        } else {
+            p.pos += 1
+        }
+    }
+    
+    blocks.append(parse_post_textblock(str: content, from: starting_from, to: content.count))
+    
+    return blocks
+}
+