Chat v2: DMs, invites, and multi-community — coinos is the default, not the only

- NIP-17 private DMs (src/dm.js): kind-14 rumors in sender-signed seals under
  ephemeral wraps; interops with other nostr DM clients. Login signers gained
  encryptTo/decryptFrom so extensions and bunkers can seal to a peer; the
  inbox listens for both the login npub and the wallet key and publishes a
  kind-10050 DM-relay list for the wallet key when none exists.
- Concord invites (CORD-05): mint shareable links (33301 bundle on relays,
  keys only in the URL fragment), join by pasting a link or opening
  v3.coinos.io/invite/…, and direct invites giftwrapped to an npub with the
  k-tag index hint. Bundles self-certify the founder before anything joins.
- Multi-community: home view lists DM threads and communities; found your own
  community in-app (owner-signed genesis). coinos stays baked in as default.
- Welcome DM: the names registrar DMs every first-time registrant from Adam's
  npub on claim (config: welcome{sk,message}; deduped in registrar state).
  Every new wallet auto-claims a payment address, so every new user gets one.
- relay.coinos.io write policy now allows 33301/13302/13303.

Co-Authored-By: Claude Fable 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01Wvj4aoeMZwA7VUGdJP9Swi

1 files changed, 88 insertions, 0 deletions

diff --git a/src/dm.js b/src/dm.js
new file mode 100644
index 0000000..70cf46b
--- /dev/null
+++ b/src/dm.js
@@ -0,0 +1,88 @@
+// NIP-17 private DMs: kind 14 rumor, kind 13 seal (sender-signed), kind 1059
+// wrap under a single-use ephemeral key to the recipient. Interops with
+// 0xchat/Amethyst/etc. Works with a raw secret key (Uint8Array) or a
+// nostr-login signer adapter carrying { pubkey, signEvent, encryptTo,
+// decryptFrom } — the seal is encrypted to the peer, so remote signers need
+// the peer variants (added alongside encryptSelf/decryptSelf).
+
+import { finalizeEvent, generateSecretKey, getPublicKey, getEventHash, verifyEvent } from 'nostr-tools/pure';
+import * as nip44 from 'nostr-tools/nip44';
+
+const now = () => Math.floor(Date.now() / 1000);
+// NIP-59: outer layers carry timestamps tweaked into the past two days so the
+// wrap's time reveals nothing; the rumor keeps the true time.
+const tweaked = () => now() - Math.floor(Math.random() * 2 * 24 * 3600);
+
+const asSigner = (skOrSigner) =>
+  skOrSigner instanceof Uint8Array
+    ? {
+        pubkey: getPublicKey(skOrSigner),
+        signEvent: async (e) => finalizeEvent(e, skOrSigner),
+        encryptTo: async (peer, txt) => nip44.encrypt(txt, nip44.getConversationKey(skOrSigner, peer)),
+        decryptFrom: async (peer, ct) => nip44.decrypt(ct, nip44.getConversationKey(skOrSigner, peer)),
+      }
+    : skOrSigner;
+
+// Build the wrap for one receiver (the recipient, or the sender's own copy).
+// Returns the kind 1059 event to publish at the receiver's inbox.
+// extraTags ride the outer wrap unencrypted — used only for the Direct
+// Invite index hint ["k","3313"] (CORD-05 §6); never put content there.
+export async function wrapDM(skOrSigner, receiverPk, rumor, extraTags = []) {
+  const signer = asSigner(skOrSigner);
+  const seal = await signer.signEvent({
+    kind: 13,
+    content: await signer.encryptTo(receiverPk, JSON.stringify(rumor)),
+    tags: [],
+    created_at: tweaked(),
+  });
+  const eph = generateSecretKey();
+  return finalizeEvent(
+    {
+      kind: 1059,
+      content: nip44.encrypt(JSON.stringify(seal), nip44.getConversationKey(eph, receiverPk)),
+      tags: [['p', receiverPk], ...extraTags],
+      created_at: tweaked(),
+    },
+    eph
+  );
+}
+
+// A DM to a peer: the kind 14 rumor (unsigned, true timestamp) plus wraps for
+// the recipient and for the sender's own inbox (the sent-copy).
+export async function makeDM(skOrSigner, peerPk, text) {
+  const signer = asSigner(skOrSigner);
+  const rumor = {
+    kind: 14,
+    pubkey: signer.pubkey,
+    content: text,
+    tags: [['p', peerPk]],
+    created_at: now(),
+  };
+  rumor.id = getEventHash(rumor);
+  return {
+    rumor,
+    toPeer: await wrapDM(signer, peerPk, rumor),
+    toSelf: await wrapDM(signer, signer.pubkey, rumor),
+  };
+}
+
+// Open an inbound kind 1059 addressed to us. Returns
+// { rumor, author, peer } or null (not ours / not a DM / bad layer).
+// `peer` is the conversation partner: the author for received messages,
+// the p-tagged recipient for our own sent-copies.
+export async function unwrapDM(wrap, skOrSigner) {
+  const signer = asSigner(skOrSigner);
+  try {
+    const seal = JSON.parse(await signer.decryptFrom(wrap.pubkey, wrap.content));
+    if (seal.kind !== 13 || !verifyEvent(seal)) return null;
+    const rumor = JSON.parse(await signer.decryptFrom(seal.pubkey, seal.content));
+    if (rumor.pubkey !== seal.pubkey) return null;
+    if (rumor.id !== getEventHash({ ...rumor, id: undefined })) return null;
+    if (rumor.kind !== 14) return { rumor, author: seal.pubkey, peer: null };
+    const to = rumor.tags?.find((t) => t[0] === 'p')?.[1];
+    const mine = rumor.pubkey === signer.pubkey;
+    return { rumor, author: seal.pubkey, peer: mine ? to : rumor.pubkey };
+  } catch {
+    return null;
+  }
+}