"""Tests for filesystem sync handler."""

import errno
import os
import shutil
import tempfile
from pathlib import Path
from unittest.mock import patch

import pytest

from handler.filesystem.sync_handler import FSSyncHandler, get_fs_sync_handler


class TestFSSyncHandler:
    @pytest.fixture
    def temp_dir(self):
        temp_dir = tempfile.mkdtemp()
        yield temp_dir
        shutil.rmtree(temp_dir, ignore_errors=True)

    @pytest.fixture
    def handler(self):
        return FSSyncHandler.__new__(FSSyncHandler)

    @pytest.fixture(autouse=True)
    def patch_base_path(self, handler: FSSyncHandler, temp_dir):
        handler.base_path = Path(temp_dir)

    def test_build_incoming_path(self, handler: FSSyncHandler):
        path = handler.build_incoming_path("device-1")
        assert path == os.path.join("device-1", "incoming")

    def test_build_incoming_path_with_platform(self, handler):
        path = handler.build_incoming_path("device-1", "gba")
        assert path == os.path.join("device-1", "incoming", "gba")

    def test_build_outgoing_path(self, handler: FSSyncHandler):
        path = handler.build_outgoing_path("device-1")
        assert path == os.path.join("device-1", "outgoing")

    def test_build_outgoing_path_with_platform(self, handler: FSSyncHandler):
        path = handler.build_outgoing_path("device-1", "snes")
        assert path == os.path.join("device-1", "outgoing", "snes")

    def test_build_conflicts_path(self, handler: FSSyncHandler):
        path = handler.build_conflicts_path("device-1", "gba")
        assert path == os.path.join("device-1", "conflicts", "gba")

    def test_ensure_device_directories(self, handler: FSSyncHandler, temp_dir):
        handler.ensure_device_directories("test-device")
        incoming = handler.base_path / handler.build_incoming_path("test-device")
        outgoing = handler.base_path / handler.build_outgoing_path("test-device")
        assert os.path.isdir(incoming)
        assert os.path.isdir(outgoing)

    def test_list_incoming_files_empty(self, handler: FSSyncHandler):
        result = handler.list_incoming_files("nonexistent-device")
        assert result == []

    def test_list_incoming_files(self, handler: FSSyncHandler, temp_dir):
        handler.ensure_device_directories("dev-1")
        incoming_path = str(
            handler.base_path / handler.build_incoming_path("dev-1", "gba")
        )
        os.makedirs(incoming_path, exist_ok=True)
        test_file = os.path.join(incoming_path, "save.sav")
        with open(test_file, "wb") as f:
            f.write(b"test save content")

        result = handler.list_incoming_files("dev-1")
        assert len(result) == 1
        assert result[0]["platform_slug"] == "gba"
        assert result[0]["file_name"] == "save.sav"
        assert result[0]["file_size"] == 17

    def test_compute_file_hash(self, handler: FSSyncHandler, temp_dir):
        test_file = os.path.join(temp_dir, "test.bin")
        with open(test_file, "wb") as f:
            f.write(b"hello world")

        hash1 = handler.compute_file_hash(test_file)
        hash2 = handler.compute_file_hash(test_file)
        assert hash1 == hash2
        assert len(hash1) == 32  # MD5 hex length

    def test_compute_file_hash_different_content(
        self, handler: FSSyncHandler, temp_dir
    ):
        file_a = os.path.join(temp_dir, "a.bin")
        file_b = os.path.join(temp_dir, "b.bin")
        with open(file_a, "wb") as f:
            f.write(b"content a")
        with open(file_b, "wb") as f:
            f.write(b"content b")

        assert handler.compute_file_hash(file_a) != handler.compute_file_hash(file_b)

    def test_write_outgoing_file(self, handler: FSSyncHandler, temp_dir):
        path = handler.write_outgoing_file(
            device_id="dev-1",
            platform_slug="gba",
            file_name="save.sav",
            data=b"outgoing save data",
        )
        assert os.path.isfile(path)
        with open(path, "rb") as f:
            assert f.read() == b"outgoing save data"

    def test_remove_incoming_file(self, handler: FSSyncHandler, temp_dir):
        handler.ensure_device_directories("dev-1")
        incoming = str(handler.base_path / handler.build_incoming_path("dev-1", "gba"))
        os.makedirs(incoming, exist_ok=True)
        test_file = os.path.join(incoming, "to_remove.sav")
        with open(test_file, "wb") as f:
            f.write(b"data")

        assert os.path.exists(test_file)
        handler.remove_incoming_file(test_file)
        assert not os.path.exists(test_file)

    def test_remove_incoming_file_outside_base_raises(
        self, handler: FSSyncHandler, temp_dir
    ):
        outside_file = os.path.join(tempfile.gettempdir(), "outside.txt")
        with open(outside_file, "w") as f:
            f.write("should not be deleted")

        with pytest.raises(ValueError, match="outside the sync base directory"):
            handler.remove_incoming_file(outside_file)

        # Cleanup
        os.unlink(outside_file)

    def test_remove_incoming_file_nonexistent(self, handler: FSSyncHandler):
        # Should not raise for nonexistent files
        handler.remove_incoming_file("/nonexistent/path/file.sav")


class TestFSSyncHandlerLazyFactory:
    """Sync is an optional feature: if /romm/sync isn't writable (bad mount,
    wrong ownership), the app must still boot. The factory defers construction
    until first use so the error surfaces at the call site, not at startup."""

    def test_factory_raises_at_call_time_when_unwritable(self):
        """Regression for the PermissionError on /romm/sync at boot: the
        failure must surface from the factory call, not from module import."""
        get_fs_sync_handler.cache_clear()
        try:
            with patch.object(
                Path, "mkdir", side_effect=PermissionError(errno.EACCES, "denied")
            ):
                with pytest.raises(PermissionError):
                    get_fs_sync_handler()
        finally:
            get_fs_sync_handler.cache_clear()