feat(up): capture follower snapshots at ingest and backfill history

reaction_board/repository.py

@@ -410,12 +410,14 @@ class Repository:
         following: int | None = None,
         now: int | None = None,
         backfilled: bool = False,
+        live_since: int | None = None,
     ) -> int:
         """写入 UP 粉丝快照，并补齐该 UP 尚未记录粉丝数的视频。
 
         ``follower_first`` 只在首次插入时写入；``follower_latest`` 每次刷新都会
-        更新。视频上的 ``up_follower`` 是入库时快照，已有值不会被覆盖。返回本次
-        补齐的视频数。
+        更新。视频上的 ``up_follower`` 是入库时快照，已有值不会被覆盖。传入
+        ``live_since`` 时，只有 ``first_seen >= live_since`` 的视频视为实时采集，
+        更早的视频标记为回填。返回本次补齐的视频数。
         """
         now = self._now() if now is None else int(now)
         mid = int(mid)
@@ -436,14 +438,29 @@ class Repository:
                 """,
                 (mid, name, follower, following_value, now, follower, now),
             )
-            cursor = conn.execute(
-                """
-                UPDATE video
-                SET up_follower = ?, up_follower_at = ?, up_follower_backfilled = ?
-                WHERE up_mid = ? AND up_follower IS NULL
-                """,
-                (follower, now, backfill_flag, mid),
-            )
+            if live_since is None:
+                cursor = conn.execute(
+                    """
+                    UPDATE video
+                    SET up_follower = ?, up_follower_at = ?, up_follower_backfilled = ?
+                    WHERE up_mid = ? AND up_follower IS NULL
+                      AND status IN ('active', 'unfaved')
+                    """,
+                    (follower, now, backfill_flag, mid),
+                )
+            else:
+                cursor = conn.execute(
+                    """
+                    UPDATE video
+                    SET up_follower = ?, up_follower_at = ?,
+                        up_follower_backfilled = CASE
+                          WHEN first_seen >= ? THEN 0 ELSE 1
+                        END
+                    WHERE up_mid = ? AND up_follower IS NULL
+                      AND status IN ('active', 'unfaved')
+                    """,
+                    (follower, now, int(live_since), mid),
+                )
             return max(cursor.rowcount, 0)
 
         return self.db.write(run)