feat: 1-to-1 message render + web data-lake backend

backend/src/utils/read/avatars.py

@@ -0,0 +1,30 @@
+import asyncpg
+
+from utils.read.models import AvatarRef
+
+_PEER_UNIQUE_ID = """
+SELECT photo_unique_id FROM peers
+WHERE account_id = $1 AND peer_id = $2
+"""
+
+_CHAT_UNIQUE_ID = """
+SELECT photo_unique_id FROM chat_history
+WHERE account_id = $1 AND chat_id = $2 AND photo_unique_id IS NOT NULL
+ORDER BY ts DESC LIMIT 1
+"""
+
+_AVATAR = """
+SELECT unique_id, storage_key, downloaded, mime FROM avatars
+WHERE account_id = $1 AND owner_id = $2 AND unique_id = $3
+"""
+
+
+async def current_avatar(
+    pool: asyncpg.Pool, account_id: int, owner_kind: str, owner_id: int
+) -> AvatarRef | None:
+    query = _PEER_UNIQUE_ID if owner_kind == "peer" else _CHAT_UNIQUE_ID
+    unique_id = await pool.fetchval(query, account_id, owner_id)
+    if unique_id is None:
+        return None
+    row = await pool.fetchrow(_AVATAR, account_id, owner_id, unique_id)
+    return AvatarRef(**dict(row)) if row else None