feat(backend): feed of deleted and edited messages with bulk deletions grouped and a shared seen marker

backend/src/utils/read/chats.py

@@ -1,3 +1,5 @@
+from datetime import datetime
+
 import asyncpg
 
 from utils.policy.models import FolderSpec
@@ -331,6 +333,12 @@ async def get_deleted_messages(
         f"ORDER BY deleted_at DESC LIMIT ${len(params) - 1} OFFSET ${len(params)}",
         *params,
     )
+    return await _single_views(pool, account_id, rows)
+
+
+async def _single_views(
+    pool: asyncpg.Pool, account_id: int, rows: list[asyncpg.Record]
+) -> list[MessageView]:
     media_by_key = await _media_map(pool, account_id, rows)
     views: list[MessageView] = []
     for row in rows:
@@ -341,6 +349,67 @@ async def get_deleted_messages(
     return views
 
 
+async def _rows_at(
+    pool: asyncpg.Pool, account_id: int, keys: list[tuple[int, int, datetime]]
+) -> list[asyncpg.Record]:
+    if not keys:
+        return []
+    params: list[object] = [account_id]
+    clauses: list[str] = []
+    for key in keys:
+        params.extend(key)
+        n = len(params)
+        clauses.append(
+            f"(chat_id = ${n - 2} AND message_id = ${n - 1} AND date = ${n})"
+        )
+    return await pool.fetch(
+        f"SELECT {_MESSAGE_COLS} FROM messages "  # noqa: S608
+        f"WHERE account_id = $1 AND ({' OR '.join(clauses)})",
+        *params,
+    )
+
+
+async def get_messages_at(
+    pool: asyncpg.Pool, account_id: int, keys: list[tuple[int, int, datetime | None]]
+) -> dict[tuple[int, int], MessageView]:
+    dated = list(
+        dict.fromkeys((chat, message, date) for chat, message, date in keys if date)
+    )
+    rows = await _rows_at(pool, account_id, dated)
+    views = {
+        (view.chat_id, view.message_id): view
+        for view in await _single_views(pool, account_id, rows)
+    }
+    for chat_id, message_id, _ in keys:
+        if (chat_id, message_id) not in views:
+            view = await get_message(pool, account_id, chat_id, message_id)
+            if view is not None:
+                views[chat_id, message_id] = view
+    return views
+
+
+async def get_deleted_between(  # noqa: PLR0913
+    pool: asyncpg.Pool,
+    account_id: int,
+    chat_id: int,
+    since: datetime,
+    until: datetime,
+    limit: int,
+    before: tuple[datetime, int] | None = None,
+) -> list[MessageView]:
+    params: list[object] = [account_id, chat_id, since, until, limit]
+    where = "account_id = $1 AND chat_id = $2 AND deleted_at BETWEEN $3 AND $4"
+    if before is not None:
+        params.extend(before)
+        where += " AND (date, message_id) < ($6, $7)"
+    rows = await pool.fetch(
+        f"SELECT {_MESSAGE_COLS} FROM messages WHERE {where} "  # noqa: S608
+        "ORDER BY date DESC, message_id DESC LIMIT $5",
+        *params,
+    )
+    return await _single_views(pool, account_id, rows)
+
+
 async def get_message_versions(
     pool: asyncpg.Pool, account_id: int, chat_id: int, message_id: int
 ) -> list[MessageVersionView]: