feat: add smart_playlists table migration and CRUD methods

Music/Services/DatabaseService.swift

@@ -95,6 +95,15 @@ nonisolated final class DatabaseService: Sendable {
             )
         }
 
+        migrator.registerMigration("v3-create-smart-playlists") { db in
+            try db.create(table: "smart_playlists") { t in
+                t.autoIncrementedPrimaryKey("id")
+                t.column("name", .text).notNull().unique()
+                t.column("searchQuery", .text).notNull()
+                t.column("createdAt", .datetime).notNull()
+            }
+        }
+
         try migrator.migrate(db)
     }
 
@@ -340,4 +349,54 @@ nonisolated final class DatabaseService: Sendable {
             )
         }
     }
+
+    // MARK: - Smart Playlists
+
+    func createSmartPlaylist(name: String, searchQuery: String) throws -> SmartPlaylist {
+        try dbPool.write { db in
+            var smartPlaylist = SmartPlaylist(
+                id: nil, name: name, searchQuery: searchQuery, createdAt: Date()
+            )
+            try smartPlaylist.insert(db)
+            return smartPlaylist
+        }
+    }
+
+    func renameSmartPlaylist(id: Int64, name: String) throws {
+        try dbPool.write { db in
+            try db.execute(
+                sql: "UPDATE smart_playlists SET name = ? WHERE id = ?",
+                arguments: [name, id]
+            )
+        }
+    }
+
+    func updateSmartPlaylistQuery(id: Int64, searchQuery: String) throws {
+        try dbPool.write { db in
+            try db.execute(
+                sql: "UPDATE smart_playlists SET searchQuery = ? WHERE id = ?",
+                arguments: [searchQuery, id]
+            )
+        }
+    }
+
+    func deleteSmartPlaylist(id: Int64) throws {
+        try dbPool.write { db in
+            try db.execute(sql: "DELETE FROM smart_playlists WHERE id = ?", arguments: [id])
+        }
+    }
+
+    func fetchSmartPlaylists() throws -> [SmartPlaylist] {
+        try dbPool.read { db in
+            try SmartPlaylist.fetchAll(
+                db, sql: "SELECT * FROM smart_playlists ORDER BY name COLLATE NOCASE ASC"
+            )
+        }
+    }
+
+    func fetchSmartPlaylists(db: Database) throws -> [SmartPlaylist] {
+        try SmartPlaylist.fetchAll(
+            db, sql: "SELECT * FROM smart_playlists ORDER BY name COLLATE NOCASE ASC"
+        )
+    }
 }

MusicTests/SmartPlaylistTests.swift

@@ -15,4 +15,65 @@ struct SmartPlaylistTests {
         #expect(sp.searchQuery == "miles davis")
         #expect(sp.isSmartPlaylist == true)
     }
+
+    // Creates a smart playlist in the database and fetches it back.
+    @Test func createAndFetchSmartPlaylist() throws {
+        let db = try DatabaseService(inMemory: true)
+        let sp = try db.createSmartPlaylist(name: "Jazz Vibes", searchQuery: "jazz")
+
+        #expect(sp.id != nil)
+        #expect(sp.name == "Jazz Vibes")
+        #expect(sp.searchQuery == "jazz")
+
+        let all = try db.fetchSmartPlaylists()
+        #expect(all.count == 1)
+        #expect(all[0].name == "Jazz Vibes")
+    }
+
+    // Renames a smart playlist and verifies the new name persists.
+    @Test func renameSmartPlaylist() throws {
+        let db = try DatabaseService(inMemory: true)
+        let sp = try db.createSmartPlaylist(name: "Old Name", searchQuery: "old")
+        try db.renameSmartPlaylist(id: sp.id!, name: "New Name")
+
+        let all = try db.fetchSmartPlaylists()
+        #expect(all[0].name == "New Name")
+    }
+
+    // Updates the search query of a smart playlist.
+    @Test func updateSmartPlaylistQuery() throws {
+        let db = try DatabaseService(inMemory: true)
+        let sp = try db.createSmartPlaylist(name: "Jazz", searchQuery: "jazz")
+        try db.updateSmartPlaylistQuery(id: sp.id!, searchQuery: "jazz fusion")
+
+        let all = try db.fetchSmartPlaylists()
+        #expect(all[0].searchQuery == "jazz fusion")
+    }
+
+    // Deletes a smart playlist and verifies it's gone.
+    @Test func deleteSmartPlaylist() throws {
+        let db = try DatabaseService(inMemory: true)
+        let sp = try db.createSmartPlaylist(name: "To Delete", searchQuery: "delete")
+        try db.deleteSmartPlaylist(id: sp.id!)
+
+        let all = try db.fetchSmartPlaylists()
+        #expect(all.isEmpty)
+    }
+
+    // Verifies smart playlist tracks are computed via FTS5 search (not stored).
+    @Test func smartPlaylistReturnsDynamicResults() throws {
+        let db = try DatabaseService(inMemory: true)
+        var t1 = Track.fixture(fileURL: "/a.mp3", title: "Kind of Blue", artist: "Miles Davis")
+        var t2 = Track.fixture(fileURL: "/b.mp3", title: "Hotel California", artist: "Eagles")
+        var t3 = Track.fixture(fileURL: "/c.mp3", title: "Bitches Brew", artist: "Miles Davis")
+        try db.insert(&t1)
+        try db.insert(&t2)
+        try db.insert(&t3)
+
+        // Smart playlist uses the existing fetchTracks with its searchQuery
+        let results = try db.fetchTracks(search: "miles davis", sortColumn: "title", ascending: true)
+        #expect(results.count == 2)
+        #expect(results[0].title == "Bitches Brew")
+        #expect(results[1].title == "Kind of Blue")
+    }
 }