"""Unit Test Template for Claude MPM

This template provides a structured approach to writing high-quality unit tests
following the AAA (Arrange-Act-Assert) pattern and project testing standards.

Based on: tests/unit/services/cli/test_session_resume_helper.py (Gold Standard)

Usage:
    1. Copy this template to your test file location
    2. Replace MODULE_NAME with the module you're testing
    3. Replace ComponentName with your class/function name
    4. Fill in test cases following the examples

Standards:
    - Follow AAA pattern (Arrange-Act-Assert)
    - Write descriptive docstrings
    - Group tests in logical classes
    - Test happy path, edge cases, and errors
    - No sleep(), print(), or untracked skips
    - Use proper fixtures and mocking
    - Target: >90% coverage for new code
"""

from unittest.mock import MagicMock, Mock, PropertyMock, patch

import pytest

# Import the component under test
# from claude_mpm.services.MODULE_NAME import ComponentName


# ============================================================================
# TEST FIXTURES
# ============================================================================


@pytest.fixture
def sample_data():
    """Sample data for testing.

    Returns a dictionary with test data that can be used across multiple tests.
    Modify this to match your component's needs.
    """
    return {
        "id": "test-123",
        "name": "Test Item",
        "value": 42,
        "items": ["item1", "item2", "item3"],
    }


@pytest.fixture
def component_instance():
    """Create instance of component under test.

    Provides a fresh instance for each test. Modify constructor
    parameters to match your component's initialization.

    Returns:
        ComponentName: Initialized component instance
    """
    # Example: return ComponentName(config={"debug": False})


@pytest.fixture
def mock_dependency():
    """Mock external dependency.

    Creates a mock for external services, APIs, or databases.
    Use spec= to catch attribute errors.

    Returns:
        Mock: Configured mock object
    """
    mock = Mock()
    mock.method_name.return_value = "expected_value"
    return mock


# ============================================================================
# TEST INITIALIZATION
# ============================================================================


class TestInitialization:
    """Tests for component initialization and configuration.

    Tests in this class verify that the component initializes correctly
    with various configurations and handles initialization errors.
    """

    def test_init_with_defaults(self):
        """Test initialization with default values."""
        # Arrange (no setup needed for defaults)

        # Act
        # component = ComponentName()

        # Assert
        # assert component.some_attribute == expected_default
        # assert component.is_initialized is True

    def test_init_with_custom_config(self):
        """Test initialization with custom configuration."""
        # Arrange
        config = {"custom_param": "custom_value"}

        # Act
        # component = ComponentName(config=config)

        # Assert
        # assert component.custom_param == "custom_value"

    def test_init_raises_error_on_invalid_config(self):
        """Test initialization raises error with invalid configuration."""
        # Arrange
        invalid_config = {"invalid_key": None}

        # Act & Assert
        # with pytest.raises(ValueError, match="Invalid configuration"):
        #     ComponentName(config=invalid_config)


# ============================================================================
# TEST CORE FUNCTIONALITY
# ============================================================================


class TestCoreMethod:
    """Tests for the primary method/feature of the component.

    Replace 'CoreMethod' with the actual method name.
    Tests cover happy path, variations, and method-specific edge cases.
    """

    def test_returns_expected_result(self, component_instance, sample_data):
        """Test returns expected result for valid input."""
        # Arrange
        expected_result = "processed_value"

        # Act
        # result = component_instance.core_method(sample_data)

        # Assert
        # assert result == expected_result

    def test_handles_empty_input(self, component_instance):
        """Test handles empty input gracefully."""
        # Arrange
        empty_input = []

        # Act
        # result = component_instance.core_method(empty_input)

        # Assert
        # assert result == []
        # Or assert result is None, depending on expected behavior

    def test_calls_dependency_correctly(self, component_instance, mock_dependency):
        """Test calls external dependency with correct parameters."""
        # Arrange
        # component_instance.dependency = mock_dependency
        input_data = {"key": "value"}

        # Act
        # component_instance.core_method(input_data)

        # Assert
        # mock_dependency.method_name.assert_called_once_with(input_data)

    def test_returns_none_when_condition_not_met(self, component_instance):
        """Test returns None when specific condition is not met."""
        # Arrange
        data_failing_condition = {"incomplete": True}

        # Act
        # result = component_instance.core_method(data_failing_condition)

        # Assert
        # assert result is None


# ============================================================================
# TEST ERROR HANDLING
# ============================================================================


class TestErrorHandling:
    """Tests for error handling and exception scenarios.

    Verifies that the component handles errors gracefully and provides
    appropriate error messages.
    """

    def test_raises_value_error_on_invalid_input(self, component_instance):
        """Test raises ValueError for invalid input type."""
        # Arrange
        invalid_input = "should be dict, not string"

        # Act & Assert
        # with pytest.raises(ValueError, match="Expected dict"):
        #     component_instance.core_method(invalid_input)

    def test_handles_missing_required_field(self, component_instance):
        """Test handles missing required field gracefully."""
        # Arrange
        incomplete_data = {"name": "test"}  # missing required 'id' field

        # Act
        # result = component_instance.core_method(incomplete_data)

        # Assert
        # assert result is None
        # Or check that appropriate error is logged

    def test_handles_external_service_failure(
        self, component_instance, mock_dependency
    ):
        """Test handles external service failure gracefully."""
        # Arrange
        # component_instance.dependency = mock_dependency
        mock_dependency.method_name.side_effect = ConnectionError("Service unavailable")

        # Act
        # result = component_instance.core_method({"data": "test"})

        # Assert
        # assert result is None
        # Or verify error is logged/handled appropriately

    @patch("module_path.logger")
    def test_logs_error_on_exception(self, mock_logger, component_instance):
        """Test logs error when exception occurs."""
        # Arrange
        # Setup component to trigger error condition

        # Act
        # component_instance.core_method(invalid_data)

        # Assert
        # mock_logger.error.assert_called_once()


# ============================================================================
# TEST EDGE CASES
# ============================================================================


class TestEdgeCases:
    """Tests for edge cases and boundary conditions.

    Covers unusual inputs, boundary values, and special scenarios
    that might not be encountered in normal operation.
    """

    def test_handles_very_large_input(self, component_instance):
        """Test handles very large input efficiently."""
        # Arrange
        large_input = list(range(10000))

        # Act
        # result = component_instance.core_method(large_input)

        # Assert
        # assert len(result) == 10000
        # Optionally: verify performance is acceptable

    def test_handles_special_characters(self, component_instance):
        """Test handles special characters in input."""
        # Arrange
        special_data = {"name": "Test 🔐 Special Chars", "content": "日本語 content"}

        # Act
        # result = component_instance.core_method(special_data)

        # Assert
        # assert "🔐" in result
        # assert "日本語" in result

    def test_handles_null_values(self, component_instance):
        """Test handles None/null values appropriately."""
        # Arrange
        data_with_nulls = {
            "id": "123",
            "optional_field": None,
            "required_field": "value",
        }

        # Act
        # result = component_instance.core_method(data_with_nulls)

        # Assert
        # assert result is not None

    def test_handles_concurrent_access(self, component_instance):
        """Test handles concurrent access safely."""
        # Arrange
        import threading

        results = []

        def worker():
            # result = component_instance.core_method({"id": "test"})
            # results.append(result)
            pass

        # Act
        # threads = [threading.Thread(target=worker) for _ in range(10)]
        # for t in threads:
        #     t.start()
        # for t in threads:
        #     t.join()

        # Assert
        # assert len(results) == 10
        # assert all(r is not None for r in results)


# ============================================================================
# TEST ASYNC FUNCTIONALITY (if applicable)
# ============================================================================


class TestAsyncMethods:
    """Tests for async methods.

    Use pytest-asyncio for testing async functions.
    Remove this class if component doesn't have async methods.
    """

    @pytest.mark.asyncio
    async def test_async_method_success(self, component_instance):
        """Test async method completes successfully."""
        # Arrange
        input_data = {"key": "value"}

        # Act
        # result = await component_instance.async_method(input_data)

        # Assert
        # assert result is not None

    @pytest.mark.asyncio
    async def test_async_method_handles_timeout(self, component_instance):
        """Test async method handles timeout gracefully."""
        # Arrange
        # Setup conditions that would cause timeout

        # Act & Assert
        # with pytest.raises(asyncio.TimeoutError):
        #     await component_instance.async_method(slow_data, timeout=0.1)


# ============================================================================
# INTEGRATION-STYLE TESTS (within unit test file)
# ============================================================================


class TestIntegrationScenarios:
    """Integration-style tests that exercise multiple methods together.

    These tests verify end-to-end workflows within the component,
    but still mock external dependencies.
    """

    def test_complete_workflow(self, component_instance, sample_data):
        """Test complete workflow from initialization to result."""
        # Arrange
        # component = ComponentName()

        # Act
        # Step 1: Initialize
        # init_result = component.initialize(sample_data)
        # assert init_result is True

        # Step 2: Process
        # process_result = component.process()
        # assert process_result is not None

        # Step 3: Finalize
        # final_result = component.finalize()

        # Assert
        # assert final_result == expected_final_state

    def test_state_transitions(self, component_instance):
        """Test component state transitions correctly."""
        # Arrange
        # assert component_instance.state == "initial"

        # Act & Assert - verify each state transition
        # component_instance.start()
        # assert component_instance.state == "running"

        # component_instance.pause()
        # assert component_instance.state == "paused"

        # component_instance.resume()
        # assert component_instance.state == "running"

        # component_instance.stop()
        # assert component_instance.state == "stopped"


# ============================================================================
# TEST UTILITIES AND HELPERS
# ============================================================================


class TestUtilityMethods:
    """Tests for utility and helper methods.

    Tests smaller, supporting methods that are used by core functionality.
    """

    def test_validation_method_accepts_valid_input(self, component_instance):
        """Test validation method accepts valid input."""
        # Arrange
        valid_input = {"id": "123", "name": "Test"}

        # Act
        # is_valid = component_instance.validate(valid_input)

        # Assert
        # assert is_valid is True

    def test_validation_method_rejects_invalid_input(self, component_instance):
        """Test validation method rejects invalid input."""
        # Arrange
        invalid_input = {"incomplete": True}

        # Act
        # is_valid = component_instance.validate(invalid_input)

        # Assert
        # assert is_valid is False

    def test_formatting_method_formats_correctly(self, component_instance):
        """Test formatting method produces expected output."""
        # Arrange
        raw_data = {"value": 42, "unit": "pixels"}

        # Act
        # formatted = component_instance.format(raw_data)

        # Assert
        # assert formatted == "42 pixels"


# ============================================================================
# PARAMETRIZED TESTS (for testing multiple inputs)
# ============================================================================


class TestParametrizedInputs:
    """Tests using parametrize for multiple input scenarios.

    Use @pytest.mark.parametrize to test multiple similar scenarios
    without duplicating test code.
    """

    @pytest.mark.parametrize(
        "input_value,expected_output",
        [
            (0, "zero"),
            (1, "one"),
            (5, "five"),
            (10, "ten"),
        ],
    )
    def test_number_to_word(self, component_instance, input_value, expected_output):
        """Test number to word conversion for various inputs."""
        # Arrange (input_value provided by parametrize)

        # Act
        # result = component_instance.number_to_word(input_value)

        # Assert
        # assert result == expected_output

    @pytest.mark.parametrize(
        "invalid_input",
        [
            None,
            "",
            [],
            {},
            "invalid",
        ],
    )
    def test_rejects_invalid_inputs(self, component_instance, invalid_input):
        """Test rejects various types of invalid input."""
        # Arrange (invalid_input provided by parametrize)

        # Act & Assert
        # with pytest.raises(ValueError):
        #     component_instance.process(invalid_input)


# ============================================================================
# CLEANUP AND TEARDOWN
# ============================================================================


@pytest.fixture
def component_with_cleanup(tmp_path):
    """Fixture that demonstrates cleanup after test.

    Use when component creates resources that need cleanup.
    """
    # Setup
    # component = ComponentName(temp_dir=tmp_path)
    # component.initialize()

    # Yield component to test
    # yield component

    # Cleanup (runs after test completes)
    # component.shutdown()
    # Clean up any files, connections, etc.


# ============================================================================
# NOTES AND BEST PRACTICES
# ============================================================================

"""
TESTING CHECKLIST:
- [ ] All tests follow AAA pattern
- [ ] Descriptive test names and docstrings
- [ ] Tests grouped in logical classes
- [ ] Happy path covered
- [ ] Edge cases covered
- [ ] Error handling tested
- [ ] External dependencies mocked
- [ ] No sleep() calls
- [ ] No print() statements
- [ ] No untracked @pytest.mark.skip
- [ ] Tests run fast (< 100ms for unit tests)
- [ ] Coverage > 90% for tested component

COMMON PATTERNS:

1. Testing exceptions:
   with pytest.raises(ExceptionType, match="error message"):
       component.method(invalid_input)

2. Mocking:
   mock_obj = Mock(spec=RealClass)
   mock_obj.method.return_value = expected_value
   mock_obj.method.assert_called_once_with(expected_args)

3. Patching:
   @patch('module.dependency')
   def test_with_patch(self, mock_dep):
       mock_dep.return_value = mocked_value

4. Async tests:
   @pytest.mark.asyncio
   async def test_async_method(self):
       result = await component.async_method()

5. Fixtures with cleanup:
   @pytest.fixture
   def resource():
       r = create_resource()
       yield r
       r.cleanup()

6. Parametrized tests:
   @pytest.mark.parametrize("input,expected", [(1, 2), (3, 4)])
   def test_multiple(self, input, expected):
       assert process(input) == expected

REFERENCE:
- Gold Standard: tests/unit/services/cli/test_session_resume_helper.py
- Testing Standards: tests/TESTING_STANDARDS.md
- Migration Guide: tests/MIGRATION_GUIDE.md
"""
