more mention progress

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

damus/Nostr/NostrLink.swift

@@ -0,0 +1,96 @@
+//
+//  NostrLink.swift
+//  damus
+//
+//  Created by William Casarin on 2022-05-05.
+//
+
+import Foundation
+
+
+enum NostrLink {
+    case ref(ReferencedId)
+    case filter(NostrFilter)
+}
+
+func encode_pubkey_uri(_ ref: ReferencedId) -> String {
+    return "p:" + ref.ref_id
+}
+
+// TODO: bech32 and relay hints
+func encode_event_id_uri(_ ref: ReferencedId) -> String {
+    return "e:" + ref.ref_id
+}
+
+func parse_nostr_ref_uri_type(_ p: Parser) -> String? {
+    if parse_char(p, "p") {
+        return "p"
+    }
+    
+    if parse_char(p, "e") {
+        return "e"
+    }
+    
+    return nil
+}
+
+func parse_hexstr(_ p: Parser, len: Int) -> String? {
+    var i: Int = 0
+    
+    if len % 2 != 0 {
+        return nil
+    }
+    
+    let start = p.pos
+    
+    while i < len {
+        guard parse_hex_char(p) != nil else {
+            p.pos = start
+            return nil
+        }
+        i += 1
+    }
+    
+    return String(substring(p.str, start: start, end: p.pos))
+}
+
+func parse_nostr_ref_uri(_ p: Parser) -> ReferencedId? {
+    let start = p.pos
+    
+    if !parse_str(p, "nostr:") {
+        return nil
+    }
+    
+    guard let typ = parse_nostr_ref_uri_type(p) else {
+        p.pos = start
+        return nil
+    }
+    
+    if !parse_char(p, ":") {
+        p.pos = start
+        return nil
+    }
+    
+    guard let pk = parse_hexstr(p, len: 64) else {
+        p.pos = start
+        return nil
+    }
+    
+    // TODO: parse relays from nostr uris
+    return ReferencedId(ref_id: pk, relay_id: nil, key: typ)
+}
+
+func decode_nostr_uri(_ s: String) -> NostrLink? {
+    let uri = s.replacingOccurrences(of: "nostr:", with: "")
+    
+    let parts = uri.split(separator: ":")
+        .reduce(into: Array<String>()) { acc, str in
+            guard let decoded = str.removingPercentEncoding else {
+                return
+            }
+            acc.append(decoded)
+            return
+        }
+    
+    return tag_to_refid(parts).map { .ref($0) }
+}