"""Validation tests for the error handling framework itself.

This module provides basic validation that the error handling framework
is working correctly and can be used for comprehensive error testing.
"""

import os
from unittest.mock import patch

import numpy as np
import pytest

try:
    import h5py

    H5PY_AVAILABLE = True
except ImportError:
    H5PY_AVAILABLE = False
    from tests.utils.h5py_mocks import MockH5py

    h5py = MockH5py()

# Test basic functionality of our error handling fixtures


class TestFrameworkValidation:
    """Validate that the error handling framework is working correctly."""

    def test_temp_directory_fixture(self, error_temp_dir):
        """Test that error_temp_dir fixture works correctly."""
        assert os.path.exists(error_temp_dir)
        assert os.path.isdir(error_temp_dir)

        # Should be able to create files in the directory
        test_file = os.path.join(error_temp_dir, "framework_test.txt")
        with open(test_file, "w") as f:
            f.write("test content")

        assert os.path.exists(test_file)

    def test_corrupted_hdf5_fixture(self, corrupted_hdf5_file):
        """Test that corrupted_hdf5_file fixture creates corrupted files."""
        assert os.path.exists(corrupted_hdf5_file)

        # Should fail when trying to read as HDF5
        with pytest.raises((OSError, ValueError)):
            with h5py.File(corrupted_hdf5_file, "r"):
                pass

    def test_invalid_hdf5_fixture(self, invalid_hdf5_file):
        """Test that invalid_hdf5_file fixture creates invalid files."""
        assert os.path.exists(invalid_hdf5_file)

        # File should exist but not be valid HDF5
        with open(invalid_hdf5_file) as f:
            content = f.read()
            assert "This is not a valid HDF5 file" in content

        # Should fail when trying to read as HDF5
        with pytest.raises((OSError, ValueError)):
            with h5py.File(invalid_hdf5_file, "r") as f:
                pass

    def test_missing_file_fixture(self, missing_file_path):
        """Test that missing_file_path fixture provides non-existent path."""
        assert not os.path.exists(missing_file_path)

        # Should fail when trying to access
        with pytest.raises(FileNotFoundError), open(missing_file_path):
            pass

    def test_edge_case_data_fixture(self, edge_case_data):
        """Test that edge_case_data fixture provides expected data structures."""
        assert isinstance(edge_case_data, dict)

        # Should have expected categories that match the actual fixture
        expected_categories = [
            "empty_arrays",
            "zero_array",
            "single_element",
            "max_values",
            "min_positive",
            "nan_array",
            "inf_array",
            "mixed_special",
        ]

        for category in expected_categories:
            assert category in edge_case_data

        # Check empty arrays
        empty_arrays = edge_case_data["empty_arrays"]
        for _dtype_name, array in empty_arrays.items():
            assert isinstance(array, np.ndarray)
            assert len(array) == 0

        # Check single element array
        single_element = edge_case_data["single_element"]
        assert isinstance(single_element, np.ndarray)
        assert len(single_element) == 1

    def test_error_injector_fixture(self, error_injector):
        """Test that error_injector fixture works correctly."""
        # Should be able to inject errors
        target_function = "builtins.len"
        error_injector.inject_io_error(target_function, RuntimeError)

        # Cleanup should work without errors
        error_injector.cleanup()

        # Error count should be tracked
        assert error_injector.error_count >= 0

    def test_memory_limited_environment_fixture(self, memory_limited_environment):
        """Test memory limited environment simulation."""
        # The mock should be active
        assert memory_limited_environment is not None

        # Should simulate low available memory (this is mocked)
        import psutil

        memory_info = psutil.virtual_memory()

        # Under our mock, available memory should be limited
        # (128MB available vs 1GB total in the fixture)
        assert hasattr(memory_info, "available")
        assert hasattr(memory_info, "percent")

    def test_resource_exhaustion_fixture(self, resource_exhaustion):
        """Test resource exhaustion utilities."""
        # Should have expected methods
        assert hasattr(resource_exhaustion, "simulate_memory_pressure")
        assert hasattr(resource_exhaustion, "simulate_disk_full")
        assert hasattr(resource_exhaustion, "simulate_network_failure")

        # Memory pressure simulation should work
        with resource_exhaustion.simulate_memory_pressure(threshold=0.9):
            # This should simulate high memory usage
            pass

        # Disk full simulation should work
        with resource_exhaustion.simulate_disk_full():
            # This should simulate no disk space
            pass

    def test_numpy_error_scenarios_fixture(self, numpy_error_scenarios):
        """Test numpy error scenarios fixture."""
        assert isinstance(numpy_error_scenarios, dict)

        # Should have expected scenario types
        expected_scenarios = [
            "overflow",
            "underflow",
            "division_by_zero",
            "invalid_operation",
            "empty_array",
            "single_element",
        ]

        for scenario in expected_scenarios:
            if scenario in numpy_error_scenarios:
                data = numpy_error_scenarios[scenario]
                assert isinstance(data, np.ndarray)

    def test_threading_error_scenarios_fixture(self, threading_error_scenarios):
        """Test threading error scenarios fixture."""
        # Should have expected methods
        assert hasattr(threading_error_scenarios, "deadlock_simulation")
        assert hasattr(threading_error_scenarios, "race_condition_data")
        assert hasattr(threading_error_scenarios, "thread_exception")

        # Race condition data should be a dict with expected structure
        race_data = threading_error_scenarios.race_condition_data()
        assert isinstance(race_data, dict)
        assert "counter" in race_data
        assert "lock" in race_data

        # Thread exception should create a thread that will fail
        failing_thread = threading_error_scenarios.thread_exception()
        assert hasattr(failing_thread, "start")
        assert hasattr(failing_thread, "join")


class TestBasicErrorHandling:
    """Test basic error handling patterns used throughout the framework."""

    def test_file_not_found_handling(self, error_temp_dir):
        """Test basic file not found error handling."""
        non_existent_file = os.path.join(error_temp_dir, "does_not_exist.h5")

        # Should handle file not found gracefully
        with pytest.raises(FileNotFoundError):
            with h5py.File(non_existent_file, "r"):
                pass

    def test_memory_allocation_error_simulation(self):
        """Test simulating memory allocation errors."""
        with patch("numpy.zeros") as mock_zeros:
            mock_zeros.side_effect = MemoryError("Simulated memory error")

            # Should raise the simulated error
            with pytest.raises(MemoryError):
                np.zeros(1000)

    def test_permission_error_simulation(self, error_temp_dir):
        """Test permission error simulation."""
        if os.name == "nt":  # Skip on Windows
            pytest.skip("Permission test not applicable on Windows")

        restricted_file = os.path.join(error_temp_dir, "restricted.txt")

        # Create file
        with open(restricted_file, "w") as f:
            f.write("restricted content")

        # Remove permissions
        os.chmod(restricted_file, 0o000)

        try:
            # Should raise permission error
            with pytest.raises(PermissionError), open(restricted_file) as f:
                pass
        finally:
            # Restore permissions for cleanup
            os.chmod(restricted_file, 0o644)

    def test_io_error_simulation(self, error_temp_dir):
        """Test I/O error simulation."""
        test_file = os.path.join(error_temp_dir, "io_error_test.txt")

        # Create file
        with open(test_file, "w") as f:
            f.write("test content")

        # Simulate I/O error using mock
        with patch("builtins.open") as mock_open:
            mock_open.side_effect = OSError("Simulated I/O error")

            with pytest.raises(IOError), open(test_file) as f:
                pass

    def test_type_error_handling(self):
        """Test type error handling."""

        # Function that expects specific type
        def process_array(arr):
            if not isinstance(arr, np.ndarray):
                raise TypeError("Expected numpy array")
            return arr.sum()

        # Should handle type errors gracefully
        with pytest.raises(TypeError):
            process_array("not an array")

        # Should work with correct type
        valid_array = np.array([1, 2, 3])
        result = process_array(valid_array)
        assert result == 6

    def test_value_error_handling(self):
        """Test value error handling."""

        # Function that validates input values
        def calculate_sqrt(x):
            if x < 0:
                raise ValueError("Cannot calculate square root of negative number")
            return np.sqrt(x)

        # Should handle invalid values
        with pytest.raises(ValueError):
            calculate_sqrt(-1)

        # Should work with valid values
        result = calculate_sqrt(4)
        assert result == 2.0

    def test_exception_chaining(self):
        """Test exception chaining and context preservation."""

        def outer_function():
            try:
                inner_function()
            except ValueError as e:
                raise RuntimeError("Outer function failed") from e

        def inner_function():
            raise ValueError("Inner function error")

        # Should preserve exception chain
        with pytest.raises(RuntimeError) as exc_info:
            outer_function()

        # Should have chained exception information
        assert exc_info.value.__cause__ is not None
        assert isinstance(exc_info.value.__cause__, ValueError)
        assert "Inner function error" in str(exc_info.value.__cause__)


class TestFrameworkIntegration:
    """Test integration between different parts of the error handling framework."""

    def test_multiple_fixture_interaction(
        self, error_temp_dir, edge_case_data, error_injector
    ):
        """Test that multiple fixtures can work together."""
        # Create a test file using temp directory
        test_file = os.path.join(error_temp_dir, "integration_test.h5")

        with h5py.File(test_file, "w") as f:
            # Use edge case data in the file
            empty_array = edge_case_data["empty_arrays"]["empty_float"]
            single_array = edge_case_data["single_element"]

            f.create_dataset(
                "empty_data", data=empty_array if len(empty_array) > 0 else [0]
            )
            f.create_dataset("single_data", data=single_array)

        # File should exist and be readable
        assert os.path.exists(test_file)

        with h5py.File(test_file, "r") as f:
            assert "single_data" in f
            assert len(f["single_data"]) == 1

        # Error injector should work with the file (stub implementation)
        error_injector.inject_io_error("h5py.File", IOError)

        # Test that error injection was recorded (since this is a stub)
        assert error_injector.should_fail("h5py.File") is True

        # File should still be readable since error injector is a stub
        with h5py.File(test_file, "r") as f:
            assert "single_data" in f

        # Cleanup
        error_injector.cleanup()

    def test_error_handling_consistency(self, error_temp_dir):
        """Test that error handling is consistent across different scenarios."""
        # Test multiple error types in sequence
        error_types = [
            (FileNotFoundError, lambda: open("/nonexistent/file.txt")),
            (ValueError, lambda: int("not_a_number")),
            (TypeError, lambda: len(None)),
            (ZeroDivisionError, lambda: 1 / 0),
        ]

        for expected_error, operation in error_types:
            with pytest.raises(expected_error):
                operation()

    def test_cleanup_after_errors(self, error_temp_dir, error_injector):
        """Test that cleanup works properly after various error conditions."""
        # Create resources that need cleanup
        test_files = []
        for i in range(3):
            test_file = os.path.join(error_temp_dir, f"cleanup_test_{i}.txt")
            with open(test_file, "w") as f:
                f.write(f"test content {i}")
            test_files.append(test_file)

        # Inject errors and cause failures
        error_injector.inject_io_error("builtins.open", IOError)

        # Some operations should fail
        failed_operations = 0
        for test_file in test_files:
            try:
                with open(test_file) as f:
                    pass
            except OSError:
                failed_operations += 1

        # Cleanup should work
        error_injector.cleanup()

        # Files should still exist (not affected by error injection cleanup)
        for test_file in test_files:
            assert os.path.exists(test_file)

        # Should be able to access files normally after cleanup
        for test_file in test_files:
            with open(test_file) as f:
                content = f.read()
                assert "test content" in content
