"""Unit tests for mixin discovery system."""

import pytest
import sys
from unittest.mock import Mock, patch, MagicMock
from pathlib import Path
from typing import List, Type, Any

from tests.fixtures.test_utils import BaseTestCase

# Import will be mocked for tests that don't need full functionality
try:
    from autoclean.mixins import (
        DISCOVERED_MIXINS,
        _BASE_MIXIN_CLASS,
        _discovered_other_mixins,
        _warn_on_method_collisions
    )
    from autoclean.mixins.base import BaseMixin
    MIXINS_AVAILABLE = True
except ImportError:
    MIXINS_AVAILABLE = False


@pytest.mark.skipif(not MIXINS_AVAILABLE, reason="Mixins module not available")
class TestMixinDiscovery:
    """Test the mixin discovery system."""
    
    def test_discovered_mixins_is_tuple(self):
        """Test that DISCOVERED_MIXINS is a tuple."""
        from autoclean.mixins import DISCOVERED_MIXINS
        
        assert isinstance(DISCOVERED_MIXINS, tuple)
        assert len(DISCOVERED_MIXINS) > 0  # Should have at least BaseMixin
    
    def test_base_mixin_included(self):
        """Test that BaseMixin functionality is included in discovered mixins."""
        from autoclean.mixins import DISCOVERED_MIXINS, BaseMixin
        
        # DISCOVERED_MIXINS contains the combined mixin class, not individual mixins
        assert len(DISCOVERED_MIXINS) == 1
        combined_mixin = DISCOVERED_MIXINS[0]
        
        # The combined mixin should inherit from BaseMixin
        assert issubclass(combined_mixin, BaseMixin)
    
    def test_base_mixin_class_availability(self):
        """Test that _BASE_MIXIN_CLASS is properly set."""
        from autoclean.mixins import _BASE_MIXIN_CLASS, BaseMixin
        
        assert _BASE_MIXIN_CLASS == BaseMixin
        assert issubclass(_BASE_MIXIN_CLASS, object)
    
    def test_discovered_mixins_are_classes(self):
        """Test that all discovered mixins are actual classes."""
        from autoclean.mixins import DISCOVERED_MIXINS
        
        for mixin in DISCOVERED_MIXINS:
            assert isinstance(mixin, type), f"{mixin} is not a class"
            assert hasattr(mixin, '__name__'), f"{mixin} has no __name__"
            assert hasattr(mixin, '__module__'), f"{mixin} has no __module__"
    
    def test_mixin_naming_convention(self):
        """Test that discovered mixins follow naming convention."""
        from autoclean.mixins import DISCOVERED_MIXINS
        
        for mixin in DISCOVERED_MIXINS:
            # Should end with 'Mixin' or 'Mixins' (for CombinedAutocleanMixins)
            assert (mixin.__name__.endswith('Mixin') or mixin.__name__.endswith('Mixins')), \
                f"Mixin {mixin.__name__} doesn't follow naming convention"
    
    def test_mixin_modules_structure(self):
        """Test that mixins come from expected module structure."""
        from autoclean.mixins import DISCOVERED_MIXINS
        
        for mixin in DISCOVERED_MIXINS:
            module_name = mixin.__module__
            # Should be from autoclean.mixins or its submodules
            assert module_name.startswith('autoclean.mixins'), \
                f"Mixin {mixin.__name__} from unexpected module: {module_name}"


@pytest.mark.skipif(not MIXINS_AVAILABLE, reason="Mixins module not available")
class TestMixinCollisionDetection:
    """Test the mixin method collision detection system."""
    
    def test_warn_on_method_collisions_no_collisions(self):
        """Test collision detection with no collisions."""
        from autoclean.mixins import _warn_on_method_collisions
        
        # Create test mixins with no collisions
        class MixinA:
            def method_a(self):
                pass
        
        class MixinB:
            def method_b(self):
                pass
        
        # Should not print warnings for no collisions
        with patch('builtins.print') as mock_print:
            _warn_on_method_collisions((MixinA, MixinB))
            # Should not print collision warnings
            collision_warnings = [call for call in mock_print.call_args_list 
                                if 'WARNING:' in str(call)]
            assert len(collision_warnings) == 0
    
    def test_warn_on_method_collisions_with_collisions(self):
        """Test collision detection with actual collisions."""
        from autoclean.mixins import _warn_on_method_collisions
        
        # Create test mixins with collisions
        class MixinA:
            def shared_method(self):
                pass
            
            def unique_a(self):
                pass
        
        class MixinB:
            def shared_method(self):
                pass
            
            def unique_b(self):
                pass
        
        # Should print warnings for collisions
        with patch('builtins.print') as mock_print:
            _warn_on_method_collisions((MixinA, MixinB))
            
            # Should print collision warning
            print_calls = [str(call) for call in mock_print.call_args_list]
            warning_calls = [call for call in print_calls if 'WARNING:' in call]
            assert len(warning_calls) > 0
            
            # Should mention the conflicting method
            assert any('shared_method' in call for call in warning_calls)
    
    def test_warn_on_method_collisions_ignores_dunder_methods(self):
        """Test that collision detection ignores dunder methods."""
        from autoclean.mixins import _warn_on_method_collisions
        
        class MixinA:
            def __init__(self):
                pass
            
            def __str__(self):
                return "A"
        
        class MixinB:
            def __init__(self):
                pass
            
            def __str__(self):
                return "B"
        
        # Should not warn about dunder method collisions
        with patch('builtins.print') as mock_print:
            _warn_on_method_collisions((MixinA, MixinB))
            
            print_calls = [str(call) for call in mock_print.call_args_list]
            # Should not mention __init__ or __str__
            assert not any('__init__' in call for call in print_calls)
            assert not any('__str__' in call for call in print_calls)
    
    def test_method_collision_precedence_detection(self):
        """Test that collision detection shows precedence information."""
        from autoclean.mixins import _warn_on_method_collisions
        
        class FirstMixin:
            def collision_method(self):
                pass
        
        class SecondMixin:
            def collision_method(self):
                pass
        
        with patch('builtins.print') as mock_print:
            _warn_on_method_collisions((FirstMixin, SecondMixin))
            
            print_calls = [str(call) for call in mock_print.call_args_list]
            
            # Should mention precedence
            precedence_calls = [call for call in print_calls if 'appears earliest' in call]
            assert len(precedence_calls) > 0
            
            # Should mention FirstMixin has precedence
            assert any('FirstMixin' in call for call in precedence_calls)


@pytest.mark.skipif(not MIXINS_AVAILABLE, reason="Mixins module not available")
class TestBaseMixin:
    """Test the BaseMixin class functionality."""
    
    def test_base_mixin_importable(self):
        """Test that BaseMixin can be imported."""
        from autoclean.mixins.base import BaseMixin
        
        assert BaseMixin is not None
        assert isinstance(BaseMixin, type)
    
    def test_base_mixin_has_expected_interface(self):
        """Test that BaseMixin has expected interface."""
        from autoclean.mixins.base import BaseMixin
        
        # Should be a class that can be inherited from
        class TestClass(BaseMixin):
            pass
        
        instance = TestClass()
        assert isinstance(instance, BaseMixin)
    
    def test_base_mixin_in_discovered_mixins(self):
        """Test that BaseMixin functionality is properly included in discovery."""
        from autoclean.mixins import DISCOVERED_MIXINS
        from autoclean.mixins.base import BaseMixin
        
        # The combined mixin should inherit from BaseMixin
        combined_mixin = DISCOVERED_MIXINS[0]
        assert issubclass(combined_mixin, BaseMixin)


class TestMixinDiscoveryMocked:
    """Test mixin discovery with heavy mocking."""
    
    @patch('autoclean.mixins.pkgutil.iter_modules')
    @patch('autoclean.mixins.importlib.import_module')
    def test_mixin_discovery_mechanism(self, mock_import, mock_iter_modules):
        """Test the mixin discovery mechanism with mocks."""
        # Mock module discovery
        mock_module_info = Mock()
        mock_module_info.name = "test_module"
        mock_module_info.ispkg = False
        mock_iter_modules.return_value = [mock_module_info]
        
        # Mock module import
        mock_module = Mock()
        mock_mixin_class = type('TestMixin', (), {'test_method': lambda self: None})
        mock_module.TestMixin = mock_mixin_class
        mock_import.return_value = mock_module
        
        # The discovery mechanism should work with these mocks
        # (This tests the pattern, actual discovery is tested above)
        assert mock_iter_modules.called or not mock_iter_modules.called  # Placeholder
    
    def test_mixin_discovery_error_handling(self):
        """Test mixin discovery error handling."""
        with patch('autoclean.mixins.importlib.import_module') as mock_import:
            mock_import.side_effect = ImportError("Module not found")
            
            # Discovery should handle import errors gracefully
            # (Actual error handling tested in integration)
            assert True  # Placeholder
    
    def test_base_mixin_fallback_mechanism(self):
        """Test BaseMixin fallback mechanism."""
        with patch('autoclean.mixins.base.BaseMixin', side_effect=ImportError("BaseMixin not found")):
            # Should use placeholder when BaseMixin unavailable
            # This would be tested in actual import scenarios
            assert True  # Placeholder


class TestMixinSystemConceptual:
    """Conceptual tests for mixin system design."""
    
    def test_mixin_system_design_principles(self):
        """Test that mixin system follows good design principles."""
        if not MIXINS_AVAILABLE:
            pytest.skip("Mixins not available for design testing")
        
        from autoclean.mixins import DISCOVERED_MIXINS
        
        # Composition principle: single effective mixin that combines multiple mixins
        assert len(DISCOVERED_MIXINS) == 1  # Single combined mixin
        
        # The combined mixin should have multiple parent classes
        combined_mixin = DISCOVERED_MIXINS[0]
        assert len(combined_mixin.__mro__) > 2  # More than just object and the class itself
        
        # Single responsibility principle (each mixin should be focused)
        for mixin in DISCOVERED_MIXINS:
            # Mixin names should indicate their purpose
            assert 'Mixin' in mixin.__name__
    
    def test_mixin_extensibility_concept(self):
        """Test mixin system extensibility concept."""
        if not MIXINS_AVAILABLE:
            pytest.skip("Mixins not available for extensibility testing")
        
        from autoclean.mixins import DISCOVERED_MIXINS
        
        # Should be extensible by adding new mixins
        # New mixins should be discoverable
        # This is tested through the discovery mechanism
        assert len(DISCOVERED_MIXINS) >= 1  # At least BaseMixin
    
    def test_mixin_conflict_resolution_concept(self):
        """Test mixin conflict resolution concept."""
        if not MIXINS_AVAILABLE:
            pytest.skip("Mixins not available for conflict testing")
        
        from autoclean.mixins import _warn_on_method_collisions
        
        # System should detect and warn about conflicts
        # MRO should resolve conflicts predictably
        assert callable(_warn_on_method_collisions)


# Error handling and edge cases
class TestMixinDiscoveryEdgeCases:
    """Test mixin discovery edge cases and error conditions."""
    
    @pytest.mark.skipif(not MIXINS_AVAILABLE, reason="Mixins module not available")
    def test_empty_mixin_discovery(self):
        """Test behavior when no mixins are discovered."""
        # Note: This test is harder to mock due to the way the module loads
        # In reality, the mixin system always has at least BaseMixin
        from autoclean.mixins import DISCOVERED_MIXINS
        
        # Should always have at least one effective mixin
        assert len(DISCOVERED_MIXINS) >= 1
        # The mixin should be usable (have some methods)
        combined_mixin = DISCOVERED_MIXINS[0]
        assert hasattr(combined_mixin, '__mro__')
    
    @pytest.mark.skipif(not MIXINS_AVAILABLE, reason="Mixins module not available")
    def test_base_mixin_import_failure_fallback(self):
        """Test fallback when BaseMixin import fails."""
        # This would be tested by temporarily moving base.py
        # Or mocking the import failure
        # For now, test that the fallback mechanism exists
        from autoclean.mixins import _base_mixin_found
        
        # Should indicate whether BaseMixin was found
        assert isinstance(_base_mixin_found, bool)
    
    def test_mixin_discovery_with_invalid_modules(self):
        """Test mixin discovery with invalid modules."""
        with patch('autoclean.mixins.importlib.import_module') as mock_import:
            mock_import.side_effect = [ImportError("Invalid module"), None]
            
            # Should handle invalid modules gracefully
            # (Actual behavior depends on implementation)
            assert True  # Placeholder for graceful handling test
    
    def test_mixin_with_no_methods(self):
        """Test behavior with mixins that have no methods."""
        class EmptyMixin:
            pass
        
        # Should handle empty mixins without errors
        with patch('builtins.print') as mock_print:
            if MIXINS_AVAILABLE:
                from autoclean.mixins import _warn_on_method_collisions
                _warn_on_method_collisions((EmptyMixin,))
            
            # Should not crash on empty mixins
            assert True
    
    def test_mixin_with_non_callable_attributes(self):
        """Test behavior with mixins that have non-callable attributes."""
        class MixinWithAttributes:
            class_variable = "test"
            instance_variable = 42
            
            def actual_method(self):
                pass
        
        # Should handle non-callable attributes without issues
        if MIXINS_AVAILABLE:
            from autoclean.mixins import _warn_on_method_collisions
            _warn_on_method_collisions((MixinWithAttributes,))
        
        # Should not crash on non-callable attributes
        assert True