feat(reactions): add message reactions API and web quick reactions

app/messages/repository.py

@@ -1,8 +1,8 @@
-from sqlalchemy import delete, select
+from sqlalchemy import delete, func, select
 from sqlalchemy.ext.asyncio import AsyncSession
 
 from app.chats.models import ChatMember
-from app.messages.models import Message, MessageHidden, MessageIdempotencyKey, MessageReceipt, MessageType
+from app.messages.models import Message, MessageHidden, MessageIdempotencyKey, MessageReaction, MessageReceipt, MessageType
 
 
 async def create_message(
@@ -178,3 +178,44 @@ async def create_message_receipt(
     db.add(receipt)
     await db.flush()
     return receipt
+
+
+async def get_message_reaction(db: AsyncSession, *, message_id: int, user_id: int) -> MessageReaction | None:
+    result = await db.execute(
+        select(MessageReaction)
+        .where(MessageReaction.message_id == message_id, MessageReaction.user_id == user_id)
+        .limit(1)
+    )
+    return result.scalar_one_or_none()
+
+
+async def list_message_reactions(db: AsyncSession, *, message_id: int) -> list[tuple[str, int]]:
+    result = await db.execute(
+        select(MessageReaction.emoji, func.count(MessageReaction.id))
+        .where(MessageReaction.message_id == message_id)
+        .group_by(MessageReaction.emoji)
+        .order_by(func.count(MessageReaction.id).desc(), MessageReaction.emoji.asc())
+    )
+    return [(str(emoji), int(count)) for emoji, count in result.all()]
+
+
+async def upsert_message_reaction(
+    db: AsyncSession,
+    *,
+    message_id: int,
+    user_id: int,
+    emoji: str,
+) -> tuple[MessageReaction | None, str]:
+    existing = await get_message_reaction(db, message_id=message_id, user_id=user_id)
+    if existing and existing.emoji == emoji:
+        await db.delete(existing)
+        await db.flush()
+        return None, "removed"
+    if existing:
+        existing.emoji = emoji
+        await db.flush()
+        return existing, "updated"
+    reaction = MessageReaction(message_id=message_id, user_id=user_id, emoji=emoji)
+    db.add(reaction)
+    await db.flush()
+    return reaction, "added"