Preserve watchlist scan timestamps for UI display instead of wiping on lookback changes

core/watchlist_scanner.py

@@ -792,16 +792,33 @@ class WatchlistScanner:
             time.sleep(0.3)  # 300ms breathing room
 
             # Determine cutoff date for filtering
-            cutoff_timestamp = last_scan_timestamp
-
-            # If no last scan timestamp, use lookback period setting
-            if cutoff_timestamp is None:
-                lookback_period = self._get_lookback_period_setting()
-                if lookback_period != 'all':
-                    # Convert period to days and create cutoff date (use UTC)
-                    days = int(lookback_period)
-                    cutoff_timestamp = datetime.now(timezone.utc) - timedelta(days=days)
-                    logger.info(f"Using lookback period: {lookback_period} days (cutoff: {cutoff_timestamp})")
+            lookback_period = self._get_lookback_period_setting()
+
+            # If lookback is 'all', always return everything regardless of scan timestamp
+            if lookback_period == 'all':
+                cutoff_timestamp = None
+            elif last_scan_timestamp is not None:
+                cutoff_timestamp = last_scan_timestamp
+
+                # Check if a lookback period change requires a one-time wider window
+                rescan_cutoff = self._get_rescan_cutoff()
+                if rescan_cutoff == 'all':
+                    logger.info(f"Lookback period changed to 'all' — returning full discography")
+                    cutoff_timestamp = None
+                elif rescan_cutoff is not None:
+                    scan_ts = cutoff_timestamp
+                    if scan_ts.tzinfo is None:
+                        scan_ts = scan_ts.replace(tzinfo=timezone.utc)
+                    if rescan_cutoff.tzinfo is None:
+                        rescan_cutoff = rescan_cutoff.replace(tzinfo=timezone.utc)
+                    if rescan_cutoff < scan_ts:
+                        logger.info(f"Lookback period change detected — expanding cutoff from {cutoff_timestamp} to {rescan_cutoff}")
+                        cutoff_timestamp = rescan_cutoff
+            else:
+                # No scan timestamp — use lookback period
+                days = int(lookback_period)
+                cutoff_timestamp = datetime.now(timezone.utc) - timedelta(days=days)
+                logger.info(f"Using lookback period: {lookback_period} days (cutoff: {cutoff_timestamp})")
 
             # Filter by release date if we have a cutoff timestamp
             if cutoff_timestamp:
@@ -998,6 +1015,45 @@ class WatchlistScanner:
             logger.warning(f"Error getting lookback period setting, defaulting to 30 days: {e}")
             return '30'
 
+    def _get_rescan_cutoff(self):
+        """
+        Check if a lookback period change requires a one-time wider scan window.
+
+        When the lookback period is expanded, a 'watchlist_rescan_cutoff' metadata key
+        is set with the new cutoff date. This method returns that cutoff so the scanner
+        can use the wider window for artists scanned before the change. After a full
+        scan cycle, the key is cleared by _clear_rescan_cutoff().
+
+        Returns:
+            datetime cutoff if a rescan is pending with a specific date,
+            'all' string if lookback was set to entire discography,
+            None if no rescan is pending
+        """
+        try:
+            with self.database._get_connection() as conn:
+                cursor = conn.cursor()
+                cursor.execute("SELECT value FROM metadata WHERE key = 'watchlist_rescan_cutoff'")
+                row = cursor.fetchone()
+                if row is not None:
+                    val = row['value']
+                    if val == '':
+                        return 'all'  # Lookback set to 'all' — scan everything
+                    return datetime.fromisoformat(val)
+        except Exception as e:
+            logger.debug(f"Error reading rescan cutoff: {e}")
+        return None
+
+    def _clear_rescan_cutoff(self):
+        """Clear the one-time rescan cutoff after a full scan cycle completes."""
+        try:
+            with self.database._get_connection() as conn:
+                cursor = conn.cursor()
+                cursor.execute("DELETE FROM metadata WHERE key = 'watchlist_rescan_cutoff'")
+                conn.commit()
+                logger.info("Cleared watchlist rescan cutoff flag")
+        except Exception as e:
+            logger.debug(f"Error clearing rescan cutoff: {e}")
+
     def is_album_after_timestamp(self, album, timestamp: datetime) -> bool:
         """Check if album was released after the given timestamp"""
         try:

database/music_database.py

@@ -4895,19 +4895,14 @@ class MusicDatabase:
             return 0
     
     def clear_wishlist(self, profile_id: int = 1) -> bool:
-        """Clear all tracks from the wishlist for the given profile and reset scan timestamps"""
+        """Clear all tracks from the wishlist for the given profile"""
         try:
             with self._get_connection() as conn:
                 cursor = conn.cursor()
                 cursor.execute("DELETE FROM wishlist_tracks WHERE profile_id = ?", (profile_id,))
                 cleared_count = cursor.rowcount
-                # Reset last_scan_timestamp on this profile's watchlist artists so the next scan
-                # uses the lookback period setting (e.g. "entire discography") instead
-                # of only finding albums released after the old scan date
-                cursor.execute("UPDATE watchlist_artists SET last_scan_timestamp = NULL WHERE profile_id = ?", (profile_id,))
-                reset_count = cursor.rowcount
                 conn.commit()
-                logger.info(f"Cleared {cleared_count} tracks from wishlist, reset scan timestamps on {reset_count} artists (profile: {profile_id})")
+                logger.info(f"Cleared {cleared_count} tracks from wishlist (profile: {profile_id})")
                 return True
         except Exception as e:
             logger.error(f"Error clearing wishlist: {e}")

web_server.py

@@ -17367,14 +17367,25 @@ def set_discovery_lookback_period():
                 VALUES ('discovery_lookback_period', ?, CURRENT_TIMESTAMP)
             """, (period,))
 
-            # When expanding the lookback window (especially to "entire disco"),
-            # reset scan timestamps so the next scan re-discovers older releases
-            # that were filtered out under the previous narrower setting
-            cursor.execute("UPDATE watchlist_artists SET last_scan_timestamp = NULL")
-            reset_count = cursor.rowcount
+            # Set a one-time rescan cutoff so the next scan cycle uses the new
+            # lookback window for artists that were already scanned under the old setting.
+            # This avoids wiping last_scan_timestamp (which is needed for UI display).
+            if period == 'all':
+                # 'all' means no cutoff — store empty to signal "scan everything"
+                rescan_value = ''
+            else:
+                from datetime import datetime, timedelta, timezone
+                cutoff = datetime.now(timezone.utc) - timedelta(days=int(period))
+                rescan_value = cutoff.isoformat()
+
+            cursor.execute("""
+                INSERT OR REPLACE INTO metadata (key, value, updated_at)
+                VALUES ('watchlist_rescan_cutoff', ?, CURRENT_TIMESTAMP)
+            """, (rescan_value,))
+
             conn.commit()
 
-        print(f"✅ Discovery lookback period set to: {period}, reset scan timestamps on {reset_count} artists")
+        print(f"✅ Discovery lookback period set to: {period}")
         return jsonify({"success": True, "period": period})
 
     except Exception as e:
@@ -28821,6 +28832,12 @@ def start_watchlist_scan():
                 # Resume enrichment workers if we paused them
                 _resume_enrichment_workers(_ew_state, 'watchlist scan')
 
+                # Clear one-time rescan cutoff after full scan cycle
+                try:
+                    scanner._clear_rescan_cutoff()
+                except Exception:
+                    pass
+
                 # Always reset flag when scan completes (success or error)
                 with watchlist_timer_lock:
                     watchlist_auto_scanning = False
@@ -29809,6 +29826,12 @@ def _process_watchlist_scan_automatically(automation_id=None):
         # Resume enrichment workers if we paused them
         _resume_enrichment_workers(_ew_state, 'auto-watchlist scan')
 
+        # Clear one-time rescan cutoff after full scan cycle
+        try:
+            scanner._clear_rescan_cutoff()
+        except Exception:
+            pass
+
         # Always reset flag
         with watchlist_timer_lock:
             watchlist_auto_scanning = False