feat: add per-download yt-dlp presets and overrides

Agent-Logs-Url: https://github.com/alexta69/metube/sessions/8a3119fc-63d1-4508-a196-8c50ff248812

Co-authored-by: alexta69 <7450369+alexta69@users.noreply.github.com>

app/tests/test_config.py

@@ -33,6 +33,16 @@ class ConfigTests(unittest.TestCase):
             c = Config()
         self.assertEqual(c.YTDL_OPTIONS["quiet"], True)
 
+    def test_ytdl_option_presets_json_loaded(self):
+        presets = {"Audio extras": {"embed_thumbnail": True}}
+        with patch.dict(
+            os.environ,
+            _base_env(YTDL_OPTIONS_PRESETS=json.dumps(presets)),
+            clear=False,
+        ):
+            c = Config()
+        self.assertEqual(c.YTDL_OPTIONS_PRESETS["Audio extras"]["embed_thumbnail"], True)
+
     def test_invalid_ytdl_options_exits(self):
         with patch.dict(os.environ, _base_env(YTDL_OPTIONS="not-json"), clear=False):
             with self.assertRaises(SystemExit):
@@ -73,6 +83,21 @@ class ConfigTests(unittest.TestCase):
         finally:
             os.unlink(path)
 
+    def test_ytdl_option_presets_file_merges(self):
+        with tempfile.NamedTemporaryFile("w", suffix=".json", delete=False) as f:
+            json.dump({"With subtitles": {"writesubtitles": True}}, f)
+            path = f.name
+        try:
+            with patch.dict(
+                os.environ,
+                _base_env(YTDL_OPTIONS_PRESETS="{}", YTDL_OPTIONS_PRESETS_FILE=path),
+                clear=False,
+            ):
+                c = Config()
+            self.assertIn("With subtitles", c.YTDL_OPTIONS_PRESETS)
+        finally:
+            os.unlink(path)
+
 
 if __name__ == "__main__":
     unittest.main()