WIP Nostr links

nostr.ts

@@ -1,4 +1,6 @@
 import { NPool, NRelay1 } from "@nostrify/nostrify";
+import { nip19 } from "@nostr/tools";
+import { lookupUsernameByPubkey } from "./directory.ts";
 import config from "./config.ts";
 
 const relayPool = new NPool({
@@ -56,3 +58,48 @@ export async function fetchProfileEvent(pubkey: string) {
 
   return events.length > 0 ? events[0] : null;
 }
+
+export async function nostrUriToUrl(uri: string): Promise<string> {
+  const bech32 = uri.replace(/^nostr:/, "");
+
+  if (bech32.match(/^(naddr|nprofile|npub)/)) {
+    try {
+      const r = nip19.decode(bech32);
+      let username;
+
+      switch (r.type) {
+        case "naddr":
+          username = await lookupUsernameByPubkey(r.data.pubkey);
+          if (username) return `/${bech32}`;
+          break;
+        case "nprofile":
+          username = await lookupUsernameByPubkey(r.data.pubkey);
+          if (username) return `/@${username}`;
+          break;
+        case "npub":
+          username = await lookupUsernameByPubkey(r.data);
+          if (username) return `/@${username}`;
+          break;
+      }
+    } catch (e) {
+      console.error(e);
+    }
+  }
+
+  return `${config.njump_url}/${bech32}`;
+}
+
+export async function replaceNostrUris(markdown: string): Promise<string> {
+  const nostrUriRegex =
+    /\((nostr:|nprofile|naddr|nevent|nrelay|npub)[a-z0-9]+\)/g;
+  const matches = markdown.match(nostrUriRegex);
+  if (!matches) return markdown;
+
+  for (const match of matches) {
+    const uri = match.slice(1, -1);
+    const url = await nostrUriToUrl(uri);
+    markdown = markdown.replace(match, `(${url})`);
+  }
+
+  return markdown;
+}