db: Save Track data when deleting

This includes the favorite status, playcount, last played timestamp, and
last started timestamp. These values will be restored if a Track with
the same mbid is created at a later time.

Signed-off-by: Anna Schumaker <Anna@NoWheyCreamery.com>

emmental/db/emmental.sql

@@ -395,6 +395,41 @@ CREATE TRIGGER tracks_active_trigger
 	END;
 
 
+/****************************************************
+ *                                                  *
+ *        Data saved when Tracks are deleted        *
+ *                                                  *
+ ****************************************************/
+
+CREATE TABLE saved_track_data (
+	mbid TEXT PRIMARY KEY,
+	favorite BOOLEAN NOT NULL DEFAULT FALSE,
+	playcount INTEGER NOT NULL DEFAULT 0,
+	lastplayed TIMESTAMP DEFAULT NULL,
+	laststarted TIMESTAMP DEFAULT NULL
+);
+
+CREATE TRIGGER tracks_delete_save BEFORE DELETE ON tracks
+	WHEN OLD.mbid != "" BEGIN
+		INSERT INTO saved_track_data
+			(mbid, favorite, playcount, lastplayed, laststarted)
+		VALUES (OLD.mbid, OLD.favorite, OLD.playcount,
+			OLD.lastplayed, OLD.laststarted);
+	END;
+
+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
+			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;
+
+
 /******************************************
  *                                        *
  *        Create Default Playlists        *

emmental/db/tracks.py

@@ -146,13 +146,15 @@ class Table(table.Table):
                       number: int = 0, length: float = 0.0, artist: str = "",
                       mbid: str = "", mtime: float = 0.0) -> sqlite3.Cursor:
         """Insert a new Track into the database."""
-        return self.sql("""INSERT INTO tracks
-                               (libraryid, mediumid, path, year, title,
-                                number, length, artist, mbid, mtime)
-                           VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
-                           RETURNING *""",
-                        library.libraryid, medium.mediumid, path, year.year,
-                        title, number, length, artist, mbid, mtime)
+        if cur := self.sql("""INSERT INTO tracks
+                                  (libraryid, mediumid, path, year, title,
+                                   number, length, artist, mbid, mtime)
+                              VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+                              RETURNING *""",
+                           library.libraryid, medium.mediumid, path, year.year,
+                           title, number, length, artist, mbid, mtime):
+            return self.sql("SELECT * FROM tracks WHERE trackid=?",
+                            cur.lastrowid)
 
     def do_sql_select_all(self) -> sqlite3.Cursor:
         """Load Tracks from the database."""

tests/db/test_tracks.py

@@ -2,6 +2,7 @@
 """Tests our track Gio.ListModel."""
 import datetime
 import pathlib
+import unittest
 import emmental.db.tracks
 import tests.util
 import unittest.mock
@@ -231,6 +232,33 @@ class TestTrackTable(tests.util.TestCase):
         cur = self.sql("SELECT COUNT(*) FROM tracks")
         self.assertEqual(cur.fetchone()["COUNT(*)"], 2)
 
+    def test_create_restore(self):
+        """Test restoring saved track data."""
+        now = datetime.datetime.now()
+        self.sql("""INSERT INTO saved_track_data
+                        (mbid, favorite, playcount, lastplayed, laststarted)
+                    VALUES (?, ?, ?, ? , ?)""", "ab-cd-ef", True, 42, now, now)
+
+        track1 = self.tracks.create(self.library, pathlib.Path("/a/b/1.ogg"),
+                                    self.medium, self.year)
+        self.assertFalse(track1.favorite)
+        self.assertEqual(track1.playcount, 0)
+        self.assertIsNone(track1.lastplayed)
+        self.assertIsNone(track1.laststarted)
+
+        row = self.sql("SELECT COUNT(*) FROM saved_track_data").fetchone()
+        self.assertEqual(row["COUNT(*)"], 1)
+
+        track2 = self.tracks.create(self.library, pathlib.Path("/a/b/2.ogg"),
+                                    self.medium, self.year, mbid="ab-cd-ef")
+        self.assertTrue(track2.favorite)
+        self.assertEqual(track2.playcount, 42)
+        self.assertEqual(track2.lastplayed, now)
+        self.assertEqual(track2.laststarted, now)
+
+        row = self.sql("SELECT COUNT(*) FROM saved_track_data").fetchone()
+        self.assertEqual(row["COUNT(*)"], 0)
+
     def test_delete(self):
         """Test deleting a Track."""
         track = self.tracks.create(self.library, pathlib.Path("/a/b/c.ogg"),
@@ -245,6 +273,29 @@ class TestTrackTable(tests.util.TestCase):
 
         self.assertFalse(track.delete())
 
+    def test_delete_save(self):
+        """Test saving track data when a track is deleted."""
+        now = datetime.datetime.now()
+        track1 = self.tracks.create(self.library, pathlib.Path("/a/b/1.ogg"),
+                                    self.medium, self.year, mbid="ab-cd-ef")
+        track2 = self.tracks.create(self.library, pathlib.Path("/a/b/2.ogg"),
+                                    self.medium, self.year)
+
+        self.sql("""UPDATE tracks
+                    SET favorite=?, laststarted=?, lastplayed=?, playcount=?
+                    WHERE trackid=?""", True, now, now, 42, track1.trackid)
+
+        track1.delete()
+        track2.delete()
+
+        rows = self.sql("SELECT * FROM saved_track_data").fetchall()
+        self.assertEqual(len(rows), 1)
+        self.assertEqual(rows[0]["mbid"], "ab-cd-ef")
+        self.assertEqual(rows[0]["favorite"], True)
+        self.assertEqual(rows[0]["laststarted"], now)
+        self.assertEqual(rows[0]["lastplayed"], now)
+        self.assertEqual(rows[0]["playcount"], 42)
+
     def test_filter(self):
         """Test filtering the Track table."""
         self.tracks.create(self.library, pathlib.Path("/a/b/1.ogg"),