feat: scheduler /watch — watched_topics + scheduler loop + /watch /unwatch /watches

src/db/database.py

@@ -99,6 +99,18 @@ CREATE TABLE IF NOT EXISTS api_usage (
     cost_usd REAL NOT NULL,
     created_at REAL NOT NULL
 );
+
+CREATE TABLE IF NOT EXISTS watched_topics (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    topic TEXT NOT NULL,
+    chat_id INTEGER NOT NULL,
+    interval_hours INTEGER NOT NULL DEFAULT 24,
+    next_run_at REAL NOT NULL,
+    last_run_at REAL,
+    enabled INTEGER NOT NULL DEFAULT 1,
+    created_at REAL NOT NULL,
+    UNIQUE(topic, chat_id)
+);
 """
 
 
@@ -319,6 +331,57 @@ class ResearchDB:
         row = await cursor.fetchone()
         return dict(row) if row else {"sessions": 0, "total_cost": 0}
 
+    # --- Watched Topics ---
+
+    async def add_watch(self, topic: str, chat_id: int, interval_hours: int) -> int:
+        now = time.time()
+        cursor = await self.db.execute(
+            """INSERT OR REPLACE INTO watched_topics
+               (topic, chat_id, interval_hours, next_run_at, created_at)
+               VALUES (?, ?, ?, ?, ?)""",
+            (topic, chat_id, interval_hours, now + interval_hours * 3600, now)
+        )
+        await self.db.commit()
+        return cursor.lastrowid
+
+    async def remove_watch(self, topic: str, chat_id: int) -> bool:
+        cursor = await self.db.execute(
+            "DELETE FROM watched_topics WHERE topic = ? AND chat_id = ?",
+            (topic, chat_id)
+        )
+        await self.db.commit()
+        return cursor.rowcount > 0
+
+    async def list_watches(self, chat_id: int) -> list[dict]:
+        cursor = await self.db.execute(
+            "SELECT * FROM watched_topics WHERE chat_id = ? ORDER BY created_at ASC",
+            (chat_id,)
+        )
+        rows = await cursor.fetchall()
+        return [dict(r) for r in rows]
+
+    async def get_due_watches(self) -> list[dict]:
+        cursor = await self.db.execute(
+            "SELECT * FROM watched_topics WHERE enabled = 1 AND next_run_at <= ?",
+            (time.time(),)
+        )
+        rows = await cursor.fetchall()
+        return [dict(r) for r in rows]
+
+    async def update_watch_run(self, watch_id: int):
+        cursor = await self.db.execute(
+            "SELECT interval_hours FROM watched_topics WHERE id = ?", (watch_id,)
+        )
+        row = await cursor.fetchone()
+        if not row:
+            return
+        now = time.time()
+        await self.db.execute(
+            "UPDATE watched_topics SET last_run_at = ?, next_run_at = ? WHERE id = ?",
+            (now, now + row[0] * 3600, watch_id)
+        )
+        await self.db.commit()
+
     # --- Maintenance ---
 
     async def purge_old_sessions(self, max_age_days: int = 30) -> dict: