From 3e67f9b014ae7456dd9068f3bc203f5f16b5dec5 Mon Sep 17 00:00:00 2001
From: futpib <futpib@gmail.com>
Date: Sat, 1 Apr 2023 04:08:59 +0400
Subject: [PATCH] Add NIP-10 thread root/reply/mention parsing

---
 index.ts      |   1 +
 nip10.test.js | 221 ++++++++++++++++++++++++++++++++++++++++++++++++++
 nip10.ts      |  73 +++++++++++++++++
 3 files changed, 295 insertions(+)
 create mode 100644 nip10.test.js
 create mode 100644 nip10.ts

diff --git a/index.ts b/index.ts
index 561a818..0295f02 100644
--- a/index.ts
+++ b/index.ts
@@ -8,6 +8,7 @@ export * from './references'
 export * as nip04 from './nip04'
 export * as nip05 from './nip05'
 export * as nip06 from './nip06'
+export * as nip10 from './nip10'
 export * as nip19 from './nip19'
 export * as nip26 from './nip26'
 export * as nip39 from './nip39'
diff --git a/nip10.test.js b/nip10.test.js
new file mode 100644
index 0000000..c020003
--- /dev/null
+++ b/nip10.test.js
@@ -0,0 +1,221 @@
+/* eslint-env jest */
+
+const {nip10} = require('./lib/nostr.cjs')
+
+describe('parse NIP10-referenced events', () => {
+
+  test('legacy + a lot of events', () => {
+    let event = {
+      tags: [
+        [
+          'e',
+          'b857504288c18a15950dd05b9e8772c62ca6289d5aac373c0a8ee5b132e94e7c'
+        ],
+        [
+          'e',
+          'bbd72f0ae14374aa8fb166b483cfcf99b57d7f4cf1600ccbf17c350040834631'
+        ],
+        [
+          'e',
+          '5e081ebb19153357d7c31e8a10b9ceeef29313f58dc8d701f66727fab02aef64'
+        ],
+        [
+          'e',
+          '49aff7ae6daeaaa2777931b90f9bb29f6cb01c5a3d7d88c8ba82d890f264afb4'
+        ],
+        [
+          'e',
+          '567b7c11f0fe582361e3cea6fcc7609a8942dfe196ee1b98d5604c93fbeea976'
+        ],
+        [
+          'e',
+          '090c037b2e399ee74d9f134758928948dd9154413ca1a1acb37155046e03a051'
+        ],
+        [
+          'e',
+          '89f220b63465c93542b1a78caa3a952cf4f196e91a50596493c8093c533ebc4d'
+        ],
+        [
+          'p',
+          '77ce56f89d1228f7ff3743ce1ad1b254857b9008564727ebd5a1f317362f6ca7'
+        ],
+        [
+          'p',
+          '534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec'
+        ],
+        [
+          'p',
+          '4ca4f5533e40da5e0508796d409e6bb35a50b26fc304345617ab017183d83ac0'
+        ]
+      ],
+    };
+
+    expect(nip10.parse(event)).toEqual({
+      "mentions": [
+        {
+          "id": "bbd72f0ae14374aa8fb166b483cfcf99b57d7f4cf1600ccbf17c350040834631",
+          "relays": [],
+        },
+        {
+          "id": "5e081ebb19153357d7c31e8a10b9ceeef29313f58dc8d701f66727fab02aef64",
+          "relays": [],
+        },
+        {
+          "id": "49aff7ae6daeaaa2777931b90f9bb29f6cb01c5a3d7d88c8ba82d890f264afb4",
+          "relays": [],
+        },
+        {
+          "id": "567b7c11f0fe582361e3cea6fcc7609a8942dfe196ee1b98d5604c93fbeea976",
+          "relays": [],
+        },
+        {
+          "id": "090c037b2e399ee74d9f134758928948dd9154413ca1a1acb37155046e03a051",
+          "relays": [],
+        },
+      ],
+      "pubkeys": [
+        "77ce56f89d1228f7ff3743ce1ad1b254857b9008564727ebd5a1f317362f6ca7",
+        "534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec",
+        "4ca4f5533e40da5e0508796d409e6bb35a50b26fc304345617ab017183d83ac0",
+      ],
+      "reply": {
+        "id": "89f220b63465c93542b1a78caa3a952cf4f196e91a50596493c8093c533ebc4d",
+        "relays": [],
+      },
+      "root": {
+        "id": "b857504288c18a15950dd05b9e8772c62ca6289d5aac373c0a8ee5b132e94e7c",
+        "relays": [],
+      },
+    });
+  });
+
+  test('legacy + 3 events', () => {
+    let event = {
+      tags: [
+        [
+          'e',
+          'b857504288c18a15950dd05b9e8772c62ca6289d5aac373c0a8ee5b132e94e7c'
+        ],
+        [
+          'e',
+          'bbd72f0ae14374aa8fb166b483cfcf99b57d7f4cf1600ccbf17c350040834631'
+        ],
+        [
+          'e',
+          '5e081ebb19153357d7c31e8a10b9ceeef29313f58dc8d701f66727fab02aef64'
+        ],
+        [
+          'p',
+          '77ce56f89d1228f7ff3743ce1ad1b254857b9008564727ebd5a1f317362f6ca7'
+        ],
+        [
+          'p',
+          '534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec'
+        ],
+        [
+          'p',
+          '4ca4f5533e40da5e0508796d409e6bb35a50b26fc304345617ab017183d83ac0'
+        ]
+      ],
+    };
+
+    expect(nip10.parse(event)).toEqual({
+      "mentions": [
+        {
+          "id": "bbd72f0ae14374aa8fb166b483cfcf99b57d7f4cf1600ccbf17c350040834631",
+          "relays": [],
+        },
+      ],
+      "pubkeys": [
+        "77ce56f89d1228f7ff3743ce1ad1b254857b9008564727ebd5a1f317362f6ca7",
+        "534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec",
+        "4ca4f5533e40da5e0508796d409e6bb35a50b26fc304345617ab017183d83ac0",
+      ],
+      "reply": {
+        "id": "5e081ebb19153357d7c31e8a10b9ceeef29313f58dc8d701f66727fab02aef64",
+        "relays": [],
+      },
+      "root": {
+        "id": "b857504288c18a15950dd05b9e8772c62ca6289d5aac373c0a8ee5b132e94e7c",
+        "relays": [],
+      },
+    });
+  });
+
+  test('legacy + 2 events', () => {
+    let event = {
+      tags: [
+        [
+          'e',
+          'b857504288c18a15950dd05b9e8772c62ca6289d5aac373c0a8ee5b132e94e7c'
+        ],
+        [
+          'e',
+          'bbd72f0ae14374aa8fb166b483cfcf99b57d7f4cf1600ccbf17c350040834631'
+        ],
+        [
+          'p',
+          '77ce56f89d1228f7ff3743ce1ad1b254857b9008564727ebd5a1f317362f6ca7'
+        ],
+        [
+          'p',
+          '534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec'
+        ],
+        [
+          'p',
+          '4ca4f5533e40da5e0508796d409e6bb35a50b26fc304345617ab017183d83ac0'
+        ]
+      ],
+    };
+
+    expect(nip10.parse(event)).toEqual({
+      "mentions": [],
+      "pubkeys": [
+        "77ce56f89d1228f7ff3743ce1ad1b254857b9008564727ebd5a1f317362f6ca7",
+        "534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec",
+        "4ca4f5533e40da5e0508796d409e6bb35a50b26fc304345617ab017183d83ac0",
+      ],
+      "reply": {
+        "id": "bbd72f0ae14374aa8fb166b483cfcf99b57d7f4cf1600ccbf17c350040834631",
+        "relays": [],
+      },
+      "root": {
+        "id": "b857504288c18a15950dd05b9e8772c62ca6289d5aac373c0a8ee5b132e94e7c",
+        "relays": [],
+      },
+    });
+  });
+
+  test('legacy + 1 event', () => {
+    let event = {
+      tags: [
+        [
+          'e',
+          '9abbfd9b9ac5ecdab45d14b8bf8d746139ea039e931a1b376d19a239f1946590'
+        ],
+        [
+          'p',
+          '534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec'
+        ]
+      ],
+    };
+
+    expect(nip10.parse(event)).toEqual({
+      "mentions": [],
+      "pubkeys": [
+        "534780e44da7b494485e85cd4cca6af4f6caa1627472432b6f2a4ece0e9e54ec",
+      ],
+      "reply": undefined,
+      "root": {
+        "id": "9abbfd9b9ac5ecdab45d14b8bf8d746139ea039e931a1b376d19a239f1946590",
+        "relays": [],
+      },
+    });
+  });
+
+  // No events with NIP-10 explicit root/reply/mention markers were found in the wild for these tests :(
+  test.todo('recommended + a lot of events');
+  test.todo('recommended + 3 events');
+  test.todo('recommended + 2 events');
+  test.todo('recommended + 1 event');
+});
diff --git a/nip10.ts b/nip10.ts
new file mode 100644
index 0000000..4ac6f68
--- /dev/null
+++ b/nip10.ts
@@ -0,0 +1,73 @@
+import type { Event } from "./event";
+import { EventPointer } from "./nip19";
+
+export type NIP10Result = {
+  /**
+   * Pointer to the root of the thread.
+   */
+  root: EventPointer | undefined;
+
+  /**
+   * Pointer to a "parent" event that parsed event replies to (responded to).
+   */
+  reply: EventPointer | undefined;
+
+  /**
+   * Pointers to events which may or may not be in the reply chain.
+   */
+  mentions: EventPointer[];
+
+  /**
+   * List of pubkeys that are involved in the thread in no particular order.
+   */
+  pubkeys: string[];
+};
+
+export function parse(event: Pick<Event, 'tags'>): NIP10Result {
+  const result: NIP10Result = {
+    reply: undefined,
+    root: undefined,
+    mentions: [],
+    pubkeys: [],
+  };
+
+  const eTags: string[][] = [];
+
+  for (const tag of event.tags) {
+    if (tag[0] === "e" && tag[1]) {
+      eTags.push(tag);
+    }
+
+    if (tag[0] === "p" && tag[1]) {
+      result.pubkeys.push(tag[1]);
+    }
+  }
+
+  for (let eTagIndex = 0; eTagIndex < eTags.length; eTagIndex++) {
+    const eTag = eTags[eTagIndex];
+
+    const [ _, eTagEventId, eTagRelayUrl, eTagMarker ] = eTag as [string, string, undefined | string, undefined | string];
+
+    const eventPointer: EventPointer = {
+      id: eTagEventId,
+      relays: eTagRelayUrl ? [eTagRelayUrl] : [],
+    };
+
+    const isFirstETag = eTagIndex === 0;
+    const isLastETag = eTagIndex === eTags.length - 1;
+
+    if (eTagMarker === 'root' || isFirstETag) {
+      result.root = eventPointer;
+      continue;
+    }
+
+    if (eTagMarker === 'reply' || isLastETag) {
+      result.reply = eventPointer;
+      continue;
+    }
+
+    result.mentions.push(eventPointer);
+  }
+
+  return result;
+}