db: Save and restore the track added date when deleting a Track

I found that deleted and restorted tracks were incorrectly showing up in
the "New Tracks" playlist. I can fix this by saving the track added date
when the tracks is deleted. The only thing I can't do easily is get the
added date for tracks that have already been deleted, so I set this to
the date of the database upgrade.

Fixes: #64 ("Save the tracks.added date when deleting")
Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/db/upgrade-v2.sql

@@ -1,3 +1,38 @@
 /* Copyright 2023 (c) Anna Schumaker */
 
 PRAGMA user_version = 2;
+
+/*
+ * The `saved_track_data` table is missing the date added field, which
+ * causes restored tracks to show up in the "New Tracks" playlist again.
+ * We can fix this by storing the date that the track was initially added
+ * to the database, and restoring it later.
+ */
+
+ALTER TABLE saved_track_data
+	ADD COLUMN added DATE DEFAULT NULL;
+
+UPDATE saved_track_data SET added = CURRENT_DATE;
+
+DROP TRIGGER tracks_delete_save;
+CREATE TRIGGER tracks_delete_save BEFORE DELETE ON tracks
+	WHEN OLD.mbid != "" BEGIN
+		INSERT INTO saved_track_data
+			(mbid, favorite, playcount, lastplayed, laststarted, added)
+		VALUES (OLD.mbid, OLD.favorite, OLD.playcount,
+			OLD.lastplayed, OLD.laststarted, OLD.added);
+	END;
+
+DROP TRIGGER tracks_insert_restore;
+CREATE TRIGGER tracks_insert_restore AFTER INSERT ON tracks
+	WHEN NEW.mbid != "" BEGIN
+		UPDATE tracks SET favorite = saved_track_data.favorite,
+				  playcount = saved_track_data.playcount,
+				  lastplayed = saved_track_data.lastplayed,
+				  laststarted = saved_track_data.laststarted,
+				  added = saved_track_data.added
+			FROM saved_track_data
+			WHERE tracks.mbid = saved_track_data.mbid AND
+				tracks.mbid = NEW.mbid;
+		DELETE FROM saved_track_data WHERE mbid = NEW.mbid;
+	END;

tests/db/test_tracks.py

@@ -248,9 +248,13 @@ class TestTrackTable(tests.util.TestCase):
     def test_create_restore(self):
         """Test restoring saved track data."""
         now = datetime.datetime.now()
+        today = datetime.date.today()
+        yesterday = today - datetime.timedelta(days=1)
         self.sql("""INSERT INTO saved_track_data
-                        (mbid, favorite, playcount, lastplayed, laststarted)
-                    VALUES (?, ?, ?, ? , ?)""", "ab-cd-ef", True, 42, now, now)
+                        (mbid, favorite, playcount,
+                         lastplayed, laststarted, added)
+                    VALUES (?, ?, ?, ? , ?, ?)""",
+                 "ab-cd-ef", True, 42, now, now, yesterday)
 
         track1 = self.tracks.create(self.library, pathlib.Path("/a/b/1.ogg"),
                                     self.medium, self.year)
@@ -258,6 +262,7 @@ class TestTrackTable(tests.util.TestCase):
         self.assertEqual(track1.playcount, 0)
         self.assertIsNone(track1.lastplayed)
         self.assertIsNone(track1.laststarted)
+        self.assertEqual(track1.added, today)
 
         row = self.sql("SELECT COUNT(*) FROM saved_track_data").fetchone()
         self.assertEqual(row["COUNT(*)"], 1)
@@ -268,6 +273,7 @@ class TestTrackTable(tests.util.TestCase):
         self.assertEqual(track2.playcount, 42)
         self.assertEqual(track2.lastplayed, now)
         self.assertEqual(track2.laststarted, now)
+        self.assertEqual(track2.added, yesterday)
 
         row = self.sql("SELECT COUNT(*) FROM saved_track_data").fetchone()
         self.assertEqual(row["COUNT(*)"], 0)
@@ -308,6 +314,7 @@ class TestTrackTable(tests.util.TestCase):
         self.assertEqual(rows[0]["laststarted"], now)
         self.assertEqual(rows[0]["lastplayed"], now)
         self.assertEqual(rows[0]["playcount"], 42)
+        self.assertEqual(rows[0]["added"], datetime.date.today())
 
     def test_filter(self):
         """Test filtering the Track table."""