From c40c6e8b300c8af147aa5bfed518397fff4506cb Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Sat, 15 Mar 2025 15:29:00 -0500
Subject: [PATCH] Support custom emoji reactions in event_stats

---
 packages/ditto/utils/custom-emoji.test.ts | 10 ++++
 packages/ditto/utils/custom-emoji.ts      | 21 +++++++
 packages/ditto/utils/stats.test.ts        | 14 ++++-
 packages/ditto/utils/stats.ts             | 67 ++++++++++++++++-------
 4 files changed, 88 insertions(+), 24 deletions(-)
 create mode 100644 packages/ditto/utils/custom-emoji.test.ts

diff --git a/packages/ditto/utils/custom-emoji.test.ts b/packages/ditto/utils/custom-emoji.test.ts
new file mode 100644
index 00000000..e9093e4e
--- /dev/null
+++ b/packages/ditto/utils/custom-emoji.test.ts
@@ -0,0 +1,10 @@
+import { assertEquals } from '@std/assert';
+
+import { parseEmojiInput } from './custom-emoji.ts';
+
+Deno.test('parseEmojiInput', () => {
+  assertEquals(parseEmojiInput('+'), { type: 'basic', value: '+' });
+  assertEquals(parseEmojiInput('🚀'), { type: 'native', native: '🚀' });
+  assertEquals(parseEmojiInput(':ditto:'), { type: 'custom', shortcode: 'ditto' });
+  assertEquals(parseEmojiInput('x'), undefined);
+});
diff --git a/packages/ditto/utils/custom-emoji.ts b/packages/ditto/utils/custom-emoji.ts
index a7a83a31..a95bacdb 100644
--- a/packages/ditto/utils/custom-emoji.ts
+++ b/packages/ditto/utils/custom-emoji.ts
@@ -70,3 +70,24 @@ export async function getCustomEmojis(
 
   return emojis;
 }
+
+/** Determine if the input is a native or custom emoji, returning a structured object or throwing an error. */
+export function parseEmojiInput(input: string):
+  | { type: 'basic'; value: '+' | '-' }
+  | { type: 'native'; native: string }
+  | { type: 'custom'; shortcode: string }
+  | undefined {
+  if (input === '+' || input === '-') {
+    return { type: 'basic', value: input };
+  }
+
+  if (/^\p{RGI_Emoji}$/v.test(input)) {
+    return { type: 'native', native: input };
+  }
+
+  const match = input.match(/^:(\w+):$/);
+  if (match) {
+    const [, shortcode] = match;
+    return { type: 'custom', shortcode };
+  }
+}
diff --git a/packages/ditto/utils/stats.test.ts b/packages/ditto/utils/stats.test.ts
index 2ebcab94..0fe7b0ae 100644
--- a/packages/ditto/utils/stats.test.ts
+++ b/packages/ditto/utils/stats.test.ts
@@ -141,16 +141,24 @@ Deno.test('updateStats with kind 7 increments reactions count', async () => {
   const { kysely, relay } = test;
 
   const note = genEvent({ kind: 1 });
-  await updateStats({ ...test, event: note });
   await relay.event(note);
 
   await updateStats({ ...test, event: genEvent({ kind: 7, content: '+', tags: [['e', note.id]] }) });
   await updateStats({ ...test, event: genEvent({ kind: 7, content: '😂', tags: [['e', note.id]] }) });
 
+  await updateStats({
+    ...test,
+    event: genEvent({
+      kind: 7,
+      content: ':ditto:',
+      tags: [['e', note.id], ['emoji', 'ditto', 'https://ditto.pub/favicon.ico']],
+    }),
+  });
+
   const stats = await getEventStats(kysely, note.id);
 
-  assertEquals(stats!.reactions, JSON.stringify({ '+': 1, '😂': 1 }));
-  assertEquals(stats!.reactions_count, 2);
+  assertEquals(stats!.reactions, JSON.stringify({ '+': 1, '😂': 1, 'ditto:https://ditto.pub/favicon.ico': 1 }));
+  assertEquals(stats!.reactions_count, 3);
 });
 
 Deno.test('updateStats with kind 5 decrements reactions count', async () => {
diff --git a/packages/ditto/utils/stats.ts b/packages/ditto/utils/stats.ts
index 922d5dca..576c6e01 100644
--- a/packages/ditto/utils/stats.ts
+++ b/packages/ditto/utils/stats.ts
@@ -7,6 +7,7 @@ import { z } from 'zod';
 import { findQuoteTag, findReplyTag, getTagSet } from '@/utils/tags.ts';
 
 import type { DittoConf } from '@ditto/conf';
+import { parseEmojiInput } from '@/utils/custom-emoji.ts';
 
 interface UpdateStatsOpts {
   conf: DittoConf;
@@ -154,31 +155,55 @@ async function handleEvent7(opts: UpdateStatsOpts): Promise<void> {
   const { kysely, event, x = 1 } = opts;
 
   const id = event.tags.findLast(([name]) => name === 'e')?.[1];
-  const emoji = event.content;
+  const result = parseEmojiInput(event.content);
 
-  if (id && emoji && (['+', '-'].includes(emoji) || /^\p{RGI_Emoji}$/v.test(emoji))) {
-    await updateEventStats(kysely, id, ({ reactions }) => {
-      const data: Record<string, number> = JSON.parse(reactions);
+  if (!id || !result) return;
 
-      // Increment or decrement the emoji count.
-      data[emoji] = (data[emoji] ?? 0) + x;
+  let url: URL | undefined;
 
-      // Remove reactions with a count of 0 or less.
-      for (const key of Object.keys(data)) {
-        if (data[key] < 1) {
-          delete data[key];
-        }
-      }
-
-      // Total reactions count.
-      const count = Object.values(data).reduce((result, value) => result + value, 0);
-
-      return {
-        reactions: JSON.stringify(data),
-        reactions_count: count,
-      };
-    });
+  if (result.type === 'custom') {
+    const tag = event.tags.find(([name, value]) => name === 'emoji' && value === result.shortcode);
+    try {
+      url = new URL(tag![2]);
+    } catch {
+      return;
+    }
   }
+
+  let key: string;
+  switch (result.type) {
+    case 'basic':
+      key = result.value;
+      break;
+    case 'native':
+      key = result.native;
+      break;
+    case 'custom':
+      key = `${result.shortcode}:${url}`;
+      break;
+  }
+
+  await updateEventStats(kysely, id, ({ reactions }) => {
+    const data: Record<string, number> = JSON.parse(reactions);
+
+    // Increment or decrement the emoji count.
+    data[key] = (data[key] ?? 0) + x;
+
+    // Remove reactions with a count of 0 or less.
+    for (const key of Object.keys(data)) {
+      if (data[key] < 1) {
+        delete data[key];
+      }
+    }
+
+    // Total reactions count.
+    const count = Object.values(data).reduce((result, value) => result + value, 0);
+
+    return {
+      reactions: JSON.stringify(data),
+      reactions_count: count,
+    };
+  });
 }
 
 /** Update stats for kind 9735 event. */