"""Unit tests for audio player preference head-script generation."""

import importlib.util
from pathlib import Path
import unittest


def _load_module():
    """Load the target module directly by file path for isolated testing."""
    module_path = Path(__file__).with_name("audio_player_preferences.py")
    spec = importlib.util.spec_from_file_location("audio_player_preferences", module_path)
    module = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(module)  # type: ignore[union-attr]
    return module


_MODULE = _load_module()
get_audio_player_preferences_head = _MODULE.get_audio_player_preferences_head
_load_preferences_script = _MODULE._load_preferences_script
_SCRIPT_PATH = Path(__file__).with_name("audio_player_preferences.js")


class AudioPlayerPreferencesHeadTests(unittest.TestCase):
    """Tests for browser script generation used by Gradio ``Blocks(head=...)``."""

    def test_external_script_asset_exists(self):
        """The externalized JavaScript asset should exist and be non-empty."""
        self.assertTrue(_SCRIPT_PATH.is_file())
        script_asset = _load_preferences_script()
        self.assertTrue(script_asset)

    def test_script_contains_volume_persistence_and_sync_hooks(self):
        """Success path: script should include storage and volume-change handling."""
        script = get_audio_player_preferences_head()
        self.assertIn("<script>", script)
        self.assertIn("localStorage", script)
        self.assertIn("volumechange", script)
        self.assertIn("MutationObserver", script)
        self.assertIn("shadowRoot", script)
        self.assertIn("syncAllVolumeControlsToPreferred", script)
        self.assertIn("volume-slider", script)
        self.assertIn("readyForPersistence", script)
        self.assertIn("wasReadyBeforeLoad", script)
        self.assertIn("markReadyForPersistence", script)
        self.assertIn("isTrustedUserEvent", script)
        self.assertIn("acestep-generate-btn", script)
        self.assertIn("player.pause()", script)
        self.assertIn("STARTUP_RESYNC_WINDOW_MS", script)
        self.assertIn("setInterval", script)
        self.assertIn("DEFAULT_VOLUME = 0.5", script)

    def test_script_resets_audio_position_on_updates(self):
        """Regression path: script should force playback to track start on reloads."""
        script = get_audio_player_preferences_head()
        self.assertIn("currentTime = 0", script)
        self.assertIn("loadstart", script)
        self.assertIn("loadedmetadata", script)

    def test_script_seeds_sane_default_volume_when_storage_missing(self):
        """Missing/invalid storage should seed and persist a 0.5 default on startup."""
        script = get_audio_player_preferences_head()
        self.assertIn("if (value === null || value === undefined || value === \"\")", script)
        self.assertIn("if (preferredVolume === null)", script)
        self.assertIn("storePreferredVolume(DEFAULT_VOLUME);", script)

    def test_script_generation_is_stable(self):
        """Non-target behavior: function should be deterministic for repeated calls."""
        script_1 = get_audio_player_preferences_head()
        script_2 = get_audio_player_preferences_head()
        self.assertEqual(script_1, script_2)


if __name__ == "__main__":
    unittest.main()