import os
import tempfile
import unittest

from src.gui.backend_client import AppCorePreferences, DesktopBackendClient, ProjectState, SessionTabSnapshot
from src.gui.backend_runner import BackendRunner


class TestBackendContract(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        cls._state_root = tempfile.TemporaryDirectory()
        cls._old_session_path = os.environ.get("State__SessionPath")
        cls._old_prefs_path = os.environ.get("State__CorePreferencesPath")
        os.environ["State__SessionPath"] = os.path.join(cls._state_root.name, "session_snapshots.json")
        os.environ["State__CorePreferencesPath"] = os.path.join(cls._state_root.name, "core_preferences.json")
        cls.runner = BackendRunner()
        cls.runner.start()
        cls.client = DesktopBackendClient()

    @classmethod
    def tearDownClass(cls):
        cls.runner.stop()
        if cls._old_session_path is None:
            os.environ.pop("State__SessionPath", None)
        else:
            os.environ["State__SessionPath"] = cls._old_session_path
        if cls._old_prefs_path is None:
            os.environ.pop("State__CorePreferencesPath", None)
        else:
            os.environ["State__CorePreferencesPath"] = cls._old_prefs_path
        cls._state_root.cleanup()

    def test_project_round_trip(self):
        with tempfile.TemporaryDirectory() as tmp:
            project_file = os.path.join(tmp, ".lyricproject")
            state = ProjectState(
                version=2,
                name="demo",
                open_files=[os.path.join(tmp, "one.lmd")],
                active_file=os.path.join(tmp, "one.lmd"),
                cursor_positions={os.path.join(tmp, "one.lmd"): 12},
                scratchpad_open=True,
            )
            self.client.write_project(project_file, state)
            loaded = self.client.read_project(project_file)
            self.assertEqual(state.to_payload(), loaded.to_payload())

    def test_session_round_trip(self):
        snapshot = SessionTabSnapshot(
            tab_id="untitled::0",
            file_path=None,
            display_name="Untitled",
            content="hook line",
            cursor_position=4,
            is_dirty=True,
            is_untitled=True,
            snapshot_mtime=None,
            workspace_root=None,
            updated_at="2026-03-13T00:00:00+00:00",
        )
        self.client.save_session(None, [snapshot])
        loaded = self.client.load_session(None)
        self.assertEqual(1, len(loaded))
        self.assertEqual(snapshot.display_name, loaded[0].display_name)
        self.client.clear_session(None)

    def test_core_preferences_round_trip(self):
        prefs = AppCorePreferences(
            reopen_last_project=False,
            restore_unsaved_tabs=False,
            last_project_file="C:/demo/.lyricproject",
        )
        self.client.save_core_preferences(prefs)
        loaded = self.client.load_core_preferences()
        self.assertEqual(prefs, loaded)

    def test_file_operations_round_trip(self):
        with tempfile.TemporaryDirectory() as tmp:
            file_path = os.path.join(tmp, "draft.lmd")
            renamed_path = os.path.join(tmp, "renamed.lmd")

            created = self.client.create_entry(file_path)
            self.assertTrue(created.success, created.message)

            written = self.client.write_file(file_path, "verse")
            self.assertTrue(written.success, written.message)

            loaded = self.client.read_file(file_path)
            self.assertTrue(loaded.success, loaded.message)
            self.assertEqual("verse", loaded.content)

            renamed = self.client.rename_entry(file_path, renamed_path, tmp)
            self.assertTrue(renamed.success, renamed.message)

            deleted = self.client.delete_entry(renamed_path, tmp)
            self.assertTrue(deleted.success, deleted.message)


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