feat: add api and mcp

backend/src/utils/read/chats.py

@@ -0,0 +1,105 @@
+import asyncpg
+
+from utils.read.models import ChatListItem, MessageVersionView, MessageView, Page
+
+_MESSAGE_COLS = (
+    "chat_id, message_id, date, sender_id, text, "
+    "has_media, is_self_destruct, edited_at, deleted_at"
+)
+
+
+def _peer_title(
+    first: str | None, last: str | None, username: str | None
+) -> str | None:
+    name = " ".join(part for part in (first, last) if part)
+    return name or username
+
+
+async def list_chats(
+    pool: asyncpg.Pool, account_id: int, page: Page
+) -> list[ChatListItem]:
+    rows = await pool.fetch(
+        "SELECT m.chat_id, count(*) AS message_count, max(m.date) AS last_date, "
+        "(SELECT p.first_name FROM peers p "
+        "WHERE p.account_id = $1 AND p.peer_id = m.chat_id) AS first_name, "
+        "(SELECT p.last_name FROM peers p "
+        "WHERE p.account_id = $1 AND p.peer_id = m.chat_id) AS last_name, "
+        "(SELECT p.username FROM peers p "
+        "WHERE p.account_id = $1 AND p.peer_id = m.chat_id) AS username, "
+        "(SELECT ch.title FROM chat_history ch "
+        "WHERE ch.account_id = $1 AND ch.chat_id = m.chat_id "
+        "AND ch.title IS NOT NULL ORDER BY ch.ts DESC LIMIT 1) AS group_title "
+        "FROM messages m WHERE m.account_id = $1 "
+        "GROUP BY m.chat_id ORDER BY last_date DESC LIMIT $2 OFFSET $3",
+        account_id,
+        page.capped_limit,
+        page.offset,
+    )
+    items = []
+    for row in rows:
+        title = row["group_title"] or _peer_title(
+            row["first_name"], row["last_name"], row["username"]
+        )
+        items.append(
+            ChatListItem(
+                chat_id=row["chat_id"],
+                title=title,
+                message_count=row["message_count"],
+                last_date=row["last_date"],
+            )
+        )
+    return items
+
+
+async def get_chat_history(
+    pool: asyncpg.Pool,
+    account_id: int,
+    chat_id: int,
+    page: Page,
+    *,
+    include_deleted: bool = True,
+) -> list[MessageView]:
+    where = "account_id = $1 AND chat_id = $2"
+    if not include_deleted:
+        where += " AND deleted_at IS NULL"
+    rows = await pool.fetch(
+        f"SELECT {_MESSAGE_COLS} FROM messages WHERE {where} "  # noqa: S608
+        "ORDER BY date DESC, message_id DESC LIMIT $3 OFFSET $4",
+        account_id,
+        chat_id,
+        page.capped_limit,
+        page.offset,
+    )
+    return [MessageView(**dict(row)) for row in rows]
+
+
+async def get_deleted_messages(
+    pool: asyncpg.Pool, account_id: int, page: Page, *, chat_id: int | None = None
+) -> list[MessageView]:
+    params: list[object] = [account_id]
+    where = "account_id = $1 AND deleted_at IS NOT NULL"
+    if chat_id is not None:
+        params.append(chat_id)
+        where += f" AND chat_id = ${len(params)}"
+    params.append(page.capped_limit)
+    params.append(page.offset)
+    rows = await pool.fetch(
+        f"SELECT {_MESSAGE_COLS} FROM messages WHERE {where} "  # noqa: S608
+        f"ORDER BY deleted_at DESC LIMIT ${len(params) - 1} OFFSET ${len(params)}",
+        *params,
+    )
+    return [MessageView(**dict(row)) for row in rows]
+
+
+async def get_message_versions(
+    pool: asyncpg.Pool, account_id: int, chat_id: int, message_id: int
+) -> list[MessageVersionView]:
+    rows = await pool.fetch(
+        "SELECT observed_at, edit_date, text FROM message_versions "
+        "WHERE account_id = $1 AND chat_id = $2 AND message_id = $3 "
+        "ORDER BY observed_at",
+        account_id,
+        chat_id,
+        message_id,
+    )
+    return [MessageVersionView(**dict(row)) for row in rows]