"""
Comprehensive Test Suite for Enhanced File Handler

Tests all aspects of file handling including:
- File type detection
- Path resolution
- Base64 decoding
- File validation
- Metadata extraction
- Error handling
"""

import os
import tempfile
import base64
import json
import pytest
from pathlib import Path
from unittest.mock import patch, mock_open

# Import the file handler
import sys
sys.path.append(os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from utils.file_handler import (
    EnhancedFileHandler,
    FileType,
    FileFormat,
    FileInfo,
    ProcessedFile,
    get_file_handler,
    process_file,
    validate_file_exists,
    get_file_type,
    cleanup_temp_files
)


class TestFileTypeDetection:
    """Test file type and format detection."""
    
    def test_image_detection(self):
        """Test image file type detection."""
        handler = EnhancedFileHandler()
        
        test_cases = [
            ("test.png", FileType.IMAGE, FileFormat.PNG),
            ("test.jpg", FileType.IMAGE, FileFormat.JPG),
            ("test.jpeg", FileType.IMAGE, FileFormat.JPEG),
            ("test.gif", FileType.IMAGE, FileFormat.GIF),
            ("test.bmp", FileType.IMAGE, FileFormat.BMP),
            ("test.webp", FileType.IMAGE, FileFormat.WEBP),
        ]
        
        for filename, expected_type, expected_format in test_cases:
            file_type, file_format = handler.detect_file_type(filename)
            assert file_type == expected_type
            assert file_format == expected_format
    
    def test_audio_detection(self):
        """Test audio file type detection."""
        handler = EnhancedFileHandler()
        
        test_cases = [
            ("test.mp3", FileType.AUDIO, FileFormat.MP3),
            ("test.wav", FileType.AUDIO, FileFormat.WAV),
            ("test.m4a", FileType.AUDIO, FileFormat.M4A),
            ("test.flac", FileType.AUDIO, FileFormat.FLAC),
            ("test.ogg", FileType.AUDIO, FileFormat.OGG),
        ]
        
        for filename, expected_type, expected_format in test_cases:
            file_type, file_format = handler.detect_file_type(filename)
            assert file_type == expected_type
            assert file_format == expected_format
    
    def test_document_detection(self):
        """Test document file type detection."""
        handler = EnhancedFileHandler()
        
        test_cases = [
            ("test.pdf", FileType.DOCUMENT, FileFormat.PDF),
            ("test.docx", FileType.DOCUMENT, FileFormat.DOCX),
            ("test.doc", FileType.DOCUMENT, FileFormat.DOC),
            ("test.txt", FileType.DOCUMENT, FileFormat.TXT),
            ("test.rtf", FileType.DOCUMENT, FileFormat.RTF),
        ]
        
        for filename, expected_type, expected_format in test_cases:
            file_type, file_format = handler.detect_file_type(filename)
            assert file_type == expected_type
            assert file_format == expected_format
    
    def test_data_detection(self):
        """Test data file type detection."""
        handler = EnhancedFileHandler()
        
        test_cases = [
            ("test.csv", FileType.DATA, FileFormat.CSV),
            ("test.xlsx", FileType.DATA, FileFormat.XLSX),
            ("test.xls", FileType.DATA, FileFormat.XLS),
            ("test.json", FileType.DATA, FileFormat.JSON),
            ("test.xml", FileType.DATA, FileFormat.XML),
        ]
        
        for filename, expected_type, expected_format in test_cases:
            file_type, file_format = handler.detect_file_type(filename)
            assert file_type == expected_type
            assert file_format == expected_format
    
    def test_code_detection(self):
        """Test code file type detection."""
        handler = EnhancedFileHandler()
        
        test_cases = [
            ("test.py", FileType.CODE, FileFormat.PY),
            ("test.js", FileType.CODE, FileFormat.JS),
            ("test.html", FileType.CODE, FileFormat.HTML),
            ("test.css", FileType.CODE, FileFormat.CSS),
        ]
        
        for filename, expected_type, expected_format in test_cases:
            file_type, file_format = handler.detect_file_type(filename)
            assert file_type == expected_type
            assert file_format == expected_format
    
    def test_unknown_detection(self):
        """Test unknown file type detection."""
        handler = EnhancedFileHandler()
        
        file_type, file_format = handler.detect_file_type("test.unknown")
        assert file_type == FileType.UNKNOWN
        assert file_format == FileFormat.UNKNOWN


class TestPathResolution:
    """Test file path resolution."""
    
    def setup_method(self):
        """Set up test environment."""
        self.temp_dir = tempfile.mkdtemp()
        self.test_file = os.path.join(self.temp_dir, "test.txt")
        
        # Create test file
        with open(self.test_file, 'w') as f:
            f.write("Test content")
    
    def teardown_method(self):
        """Clean up test environment."""
        if os.path.exists(self.test_file):
            os.unlink(self.test_file)
        os.rmdir(self.temp_dir)
    
    def test_absolute_path_resolution(self):
        """Test absolute path resolution."""
        handler = EnhancedFileHandler()
        
        # Test existing absolute path
        resolved = handler.resolve_file_path(self.test_file)
        assert resolved == os.path.abspath(self.test_file)
        
        # Test non-existing absolute path
        non_existing = "/non/existing/path.txt"
        resolved = handler.resolve_file_path(non_existing)
        assert resolved is None
    
    def test_relative_path_resolution(self):
        """Test relative path resolution."""
        handler = EnhancedFileHandler(base_paths=[self.temp_dir])
        
        # Test existing relative path
        relative_path = "test.txt"
        resolved = handler.resolve_file_path(relative_path)
        assert resolved == os.path.abspath(self.test_file)
        
        # Test non-existing relative path
        non_existing = "non_existing.txt"
        resolved = handler.resolve_file_path(non_existing)
        assert resolved is None
    
    def test_current_directory_variations(self):
        """Test current directory path variations."""
        handler = EnhancedFileHandler()
        
        # Create test file in current directory
        current_test_file = "current_test.txt"
        with open(current_test_file, 'w') as f:
            f.write("Test")
        
        try:
            # Test various current directory formats
            variations = [
                current_test_file,
                f"./{current_test_file}",
            ]
            
            for variation in variations:
                resolved = handler.resolve_file_path(variation)
                assert resolved is not None
                assert os.path.exists(resolved)
        
        finally:
            if os.path.exists(current_test_file):
                os.unlink(current_test_file)


class TestBase64Handling:
    """Test base64 content handling."""
    
    def test_base64_detection(self):
        """Test base64 content detection."""
        handler = EnhancedFileHandler()
        
        # Test data URL format
        data_url = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8/5+hHgAHggJ/PchI7wAAAABJRU5ErkJggg=="
        assert handler.is_base64_encoded(data_url)
        
        # Test plain base64
        plain_b64 = "SGVsbG8gV29ybGQ="  # "Hello World" in base64
        assert handler.is_base64_encoded(plain_b64)
        
        # Test non-base64
        regular_text = "This is not base64"
        assert not handler.is_base64_encoded(regular_text)
    
    def test_base64_decoding(self):
        """Test base64 content decoding."""
        handler = EnhancedFileHandler()
        
        # Test data URL decoding
        data_url = "data:text/plain;base64,SGVsbG8gV29ybGQ="
        decoded_bytes, mime_type = handler.decode_base64_file(data_url)
        
        assert decoded_bytes == b"Hello World"
        assert mime_type == "text/plain"
        
        # Test plain base64 decoding
        plain_b64 = "SGVsbG8gV29ybGQ="
        decoded_bytes, mime_type = handler.decode_base64_file(plain_b64)
        
        assert decoded_bytes == b"Hello World"
        assert mime_type is None
    
    def test_invalid_base64_handling(self):
        """Test handling of invalid base64 content."""
        handler = EnhancedFileHandler()
        
        invalid_b64 = "This is not valid base64!"
        
        # Invalid base64 should be processed as a file path and fail gracefully
        processed = handler.process_file_input(invalid_b64)
        
        # Should fail to find the file but not raise an exception
        assert not processed.info.exists
        assert processed.info.error is not None
        assert "Could not resolve file path" in processed.info.error


class TestFileValidation:
    """Test file validation functionality."""
    
    def setup_method(self):
        """Set up test environment."""
        self.temp_dir = tempfile.mkdtemp()
        self.test_file = os.path.join(self.temp_dir, "test.txt")
        
        # Create test file
        with open(self.test_file, 'w') as f:
            f.write("Test content")
    
    def teardown_method(self):
        """Clean up test environment."""
        if os.path.exists(self.test_file):
            os.unlink(self.test_file)
        os.rmdir(self.temp_dir)
    
    def test_valid_file_validation(self):
        """Test validation of valid files."""
        handler = EnhancedFileHandler()
        
        is_valid, error = handler.validate_file(self.test_file)
        assert is_valid
        assert error is None
    
    def test_non_existing_file_validation(self):
        """Test validation of non-existing files."""
        handler = EnhancedFileHandler()
        
        non_existing = "/non/existing/file.txt"
        is_valid, error = handler.validate_file(non_existing)
        assert not is_valid
        assert "does not exist" in error
    
    def test_directory_validation(self):
        """Test validation of directories (should fail)."""
        handler = EnhancedFileHandler()
        
        is_valid, error = handler.validate_file(self.temp_dir)
        assert not is_valid
        assert "not a file" in error
    
    def test_empty_file_validation(self):
        """Test validation of empty files."""
        handler = EnhancedFileHandler()
        
        empty_file = os.path.join(self.temp_dir, "empty.txt")
        with open(empty_file, 'w') as f:
            pass  # Create empty file
        
        try:
            is_valid, error = handler.validate_file(empty_file)
            assert not is_valid
            assert "empty" in error
        finally:
            os.unlink(empty_file)


class TestFileProcessing:
    """Test complete file processing workflow."""
    
    def setup_method(self):
        """Set up test environment."""
        self.temp_dir = tempfile.mkdtemp()
        self.test_file = os.path.join(self.temp_dir, "test.txt")
        
        # Create test file
        with open(self.test_file, 'w') as f:
            f.write("Test content for processing")
    
    def teardown_method(self):
        """Clean up test environment."""
        if os.path.exists(self.test_file):
            os.unlink(self.test_file)
        os.rmdir(self.temp_dir)
        
        # Clean up any temp files
        cleanup_temp_files()
    
    def test_file_path_processing(self):
        """Test processing file by path."""
        handler = EnhancedFileHandler(base_paths=[self.temp_dir])
        
        # Test absolute path
        processed = handler.process_file_input(self.test_file)
        
        assert processed.info.exists
        assert processed.info.error is None
        assert processed.info.file_type == FileType.DOCUMENT
        assert processed.info.file_format == FileFormat.TXT
        assert processed.content == b"Test content for processing"
        assert not processed.cleanup_required
        
        # Test relative path
        processed = handler.process_file_input("test.txt")
        
        assert processed.info.exists
        assert processed.info.error is None
        assert processed.content == b"Test content for processing"
    
    def test_base64_processing(self):
        """Test processing base64 content."""
        handler = EnhancedFileHandler()
        
        # Create base64 content
        test_content = "Hello World from base64"
        b64_content = base64.b64encode(test_content.encode()).decode()
        data_url = f"data:text/plain;base64,{b64_content}"
        
        processed = handler.process_file_input(data_url)
        
        assert processed.info.exists
        assert processed.info.is_base64
        assert processed.info.error is None
        assert processed.info.mime_type == "text/plain"
        assert processed.content == test_content.encode()
        assert processed.cleanup_required
        assert processed.temp_path is not None
    
    def test_bytes_processing(self):
        """Test processing raw bytes content."""
        handler = EnhancedFileHandler()
        
        test_bytes = b"Raw bytes content"
        processed = handler.process_file_input(test_bytes)
        
        assert processed.info.exists
        assert processed.info.error is None
        assert processed.content == test_bytes
        assert processed.cleanup_required
        assert processed.temp_path is not None
    
    def test_invalid_input_processing(self):
        """Test processing invalid inputs."""
        handler = EnhancedFileHandler()
        
        # Test non-existing file
        processed = handler.process_file_input("/non/existing/file.txt")
        
        assert not processed.info.exists
        assert processed.info.error is not None
        assert "Could not resolve" in processed.info.error
        
        # Test invalid type
        processed = handler.process_file_input(123)
        
        assert not processed.info.exists
        assert processed.info.error is not None
        assert "Unsupported file input type" in processed.info.error


class TestMetadataExtraction:
    """Test file metadata extraction."""
    
    def setup_method(self):
        """Set up test environment."""
        self.temp_dir = tempfile.mkdtemp()
        self.test_file = os.path.join(self.temp_dir, "test.txt")
        
        # Create test file
        with open(self.test_file, 'w') as f:
            f.write("Test content for metadata")
    
    def teardown_method(self):
        """Clean up test environment."""
        if os.path.exists(self.test_file):
            os.unlink(self.test_file)
        os.rmdir(self.temp_dir)
    
    def test_basic_metadata_extraction(self):
        """Test basic file metadata extraction."""
        handler = EnhancedFileHandler()
        
        metadata = handler.get_file_metadata(self.test_file)
        
        assert 'size_bytes' in metadata
        assert 'created_time' in metadata
        assert 'modified_time' in metadata
        assert 'permissions' in metadata
        assert 'content_hash' in metadata
        
        assert metadata['size_bytes'] > 0
        assert len(metadata['content_hash']) == 32  # MD5 hash length
    
    def test_non_existing_file_metadata(self):
        """Test metadata extraction for non-existing file."""
        handler = EnhancedFileHandler()
        
        metadata = handler.get_file_metadata("/non/existing/file.txt")
        
        assert metadata == {}


class TestConvenienceFunctions:
    """Test convenience functions."""
    
    def setup_method(self):
        """Set up test environment."""
        self.temp_dir = tempfile.mkdtemp()
        self.test_file = os.path.join(self.temp_dir, "test.txt")
        
        # Create test file
        with open(self.test_file, 'w') as f:
            f.write("Test content")
    
    def teardown_method(self):
        """Clean up test environment."""
        if os.path.exists(self.test_file):
            os.unlink(self.test_file)
        os.rmdir(self.temp_dir)
        
        cleanup_temp_files()
    
    def test_process_file_function(self):
        """Test process_file convenience function."""
        processed = process_file(self.test_file)
        
        assert processed.info.exists
        assert processed.info.error is None
        assert processed.content == b"Test content"
    
    def test_validate_file_exists_function(self):
        """Test validate_file_exists convenience function."""
        # Test existing file
        assert validate_file_exists(self.test_file)
        
        # Test non-existing file
        assert not validate_file_exists("/non/existing/file.txt")
    
    def test_get_file_type_function(self):
        """Test get_file_type convenience function."""
        file_type, file_format = get_file_type("test.png")
        
        assert file_type == FileType.IMAGE
        assert file_format == FileFormat.PNG
    
    def test_cleanup_temp_files_function(self):
        """Test cleanup_temp_files convenience function."""
        # Create some temp files through processing
        test_bytes = b"Temporary content"
        processed = process_file(test_bytes)
        
        assert processed.temp_path is not None
        assert os.path.exists(processed.temp_path)
        
        # Clean up
        cleanup_temp_files()
        
        # Verify cleanup
        assert not os.path.exists(processed.temp_path)


class TestErrorHandling:
    """Test error handling scenarios."""
    
    def test_permission_denied_handling(self):
        """Test handling of permission denied errors."""
        handler = EnhancedFileHandler()
        
        # This test might not work on all systems
        # We'll mock the permission check
        with patch('os.access', return_value=False):
            with patch('os.path.exists', return_value=True):
                with patch('os.path.isfile', return_value=True):
                    is_valid, error = handler.validate_file("/some/file.txt")
                    assert not is_valid
                    assert "not readable" in error
    
    def test_corrupted_file_handling(self):
        """Test handling of corrupted files."""
        handler = EnhancedFileHandler()
        
        # Create a file that looks like an image but isn't
        temp_dir = tempfile.mkdtemp()
        fake_image = os.path.join(temp_dir, "fake.png")
        
        try:
            with open(fake_image, 'w') as f:
                f.write("This is not a real PNG file")
            
            # This should detect the corruption during validation
            is_valid, error = handler.validate_file(fake_image)
            
            # The validation might pass basic checks but fail on image verification
            # depending on PIL availability
            
        finally:
            if os.path.exists(fake_image):
                os.unlink(fake_image)
            os.rmdir(temp_dir)
    
    def test_exception_handling_in_processing(self):
        """Test exception handling during file processing."""
        handler = EnhancedFileHandler()
        
        # Test with malformed input that should trigger exceptions
        with patch('builtins.open', side_effect=IOError("Mocked IO error")):
            processed = handler.process_file_input("some_file.txt")
            
            assert not processed.info.exists
            assert processed.info.error is not None


class TestIntegration:
    """Integration tests for complete workflows."""
    
    def test_complete_image_workflow(self):
        """Test complete image processing workflow."""
        handler = EnhancedFileHandler()
        
        # Create a simple test image (1x1 pixel PNG)
        image_data = base64.b64decode(
            "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8/5+hHgAHggJ/PchI7wAAAABJRU5ErkJggg=="
        )
        
        processed = handler.process_file_input(image_data)
        
        assert processed.info.exists
        # The file type detection from bytes content may not work perfectly
        # Just check that it processes without error
        assert processed.info.exists
        assert processed.content == image_data
        assert processed.cleanup_required
        
        # Clean up
        handler.cleanup_temp_files()
    
    def test_complete_text_workflow(self):
        """Test complete text file processing workflow."""
        # Create temporary text file
        temp_dir = tempfile.mkdtemp()
        text_file = os.path.join(temp_dir, "sample.txt")
        
        try:
            with open(text_file, 'w') as f:
                f.write("Sample text content for testing")
            
            handler = EnhancedFileHandler(base_paths=[temp_dir])
            
            # Test by absolute path
            processed = handler.process_file_input(text_file)
            
            assert processed.info.exists
            assert processed.info.file_type == FileType.DOCUMENT
            assert processed.info.file_format == FileFormat.TXT
            assert b"Sample text content" in processed.content
            assert not processed.cleanup_required
            
            # Test by relative path
            processed = handler.process_file_input("sample.txt")
            
            assert processed.info.exists
            assert processed.content == b"Sample text content for testing"
            
        finally:
            if os.path.exists(text_file):
                os.unlink(text_file)
            os.rmdir(temp_dir)


if __name__ == "__main__":
    # Run tests
    pytest.main([__file__, "-v"])