import os
import shutil
import yaml
import re
import sys

def loadConfig(configPath):
    """Load YAML configuration."""
    try:
        print(f"Loading configuration from {configPath}")
        with open(configPath, 'r', encoding='utf-8') as file:
            config = yaml.safe_load(file)
        
        # validate configuration
        if not config:
            raise ValueError("Empty configuration file")
        
        print("Configuration loaded successfully.")
        return config
    except FileNotFoundError:
        print(f"Error: Configuration file not found at {configPath}")
        sys.exit(1)
    except yaml.YAMLError as e:
        print(f"Error parsing YAML configuration: {e}")
        sys.exit(1)
    except ValueError as e:
        print(f"Configuration error: {e}")
        sys.exit(1)


def ensureDirectory(path):
    """Ensure that a directory exists."""
    print(f"Checking/creating directory: {path}")
    os.makedirs(path, exist_ok=True)


def copySources(config, destinationDirectory, results):
    """Copy files and folders according to copy rules."""
    print("Starting source file/folder copy process...")
    for rule in config.get('copy_rules', []):
        for source in rule.get('sources', []):
            try:
                # Distinguish between sources with explicit target and without
                if isinstance(source, dict):
                    sourcePath = source['source']
                    targetPath = os.path.join(destinationDirectory, source['target'])
                else:
                    sourcePath = source
                    targetPath = os.path.join(destinationDirectory, os.path.basename(sourcePath))

                # Create target directory
                ensureDirectory(os.path.dirname(targetPath))

                # Copy or replace mode
                if rule.get('mode') == 'replace' and os.path.exists(targetPath):
                    print(f"Replacing existing path: {targetPath}")

                    # Explicitly handle directory or file deletion
                    if os.path.isdir(targetPath):
                        shutil.rmtree(targetPath)
                    else:
                        os.remove(targetPath)

                # Update mode
                if rule.get('mode') == 'update' and os.path.exists(targetPath):
                    print(f"Checking if {sourcePath} is newer than {targetPath}")
                    srcMtime = os.path.getmtime(sourcePath)
                    destMtime = os.path.getmtime(targetPath)
                    if srcMtime <= destMtime:
                        print(f"Skipping {sourcePath}: Destination is up to date")
                        break   # Skip this source file/folder
                    
                # Copy files or directories
                if os.path.isdir(sourcePath):
                    print(f"Copying directory: {sourcePath} -> {targetPath}")
                    shutil.copytree(sourcePath, targetPath)
                    results['copies'] += 1
                else:
                    print(f"Copying file: {sourcePath} -> {targetPath}")
                    shutil.copy2(sourcePath, targetPath)
                    results['copies'] += 1
            except PermissionError:
                print(f"Error: Permission denied when copying {sourcePath}")
            except OSError as e:
                print(f"Error copying {sourcePath}: {e}")
            
    print("Source file/folder copy process completed.")


def modifyFiles(config, destinationDirectory, results):
    """Modify files according to modification rules."""
    print("Starting file modification process...")
    for rule in config.get('modification_rules', []):
        filePattern = rule.get('file_pattern', '*')
        print(f"Processing files matching pattern: {filePattern}")
        
        # Recursively search the destination directory
        for root, _, files in os.walk(destinationDirectory):
            for filename in files:
                try:
                    if re.match(filePattern, filename):
                        filePath = os.path.join(root, filename)
                        print(f"Modifying file: {filePath}")

                        # Read file content
                        with open(filePath, 'r', encoding='utf-8') as f:
                            content = f.read()

                        # Perform text replacements
                        for insertRule in rule.get('insert_rules', []):
                            if 'after_text' in insertRule:
                                print(f"  Inserting text after: {insertRule['after_text']}")
                                content = content.replace(
                                    insertRule['after_text'], 
                                    insertRule['after_text'] + insertRule['insert_text']
                                )

                            if 'before_text' in insertRule:
                                print(f"  Inserting text before: {insertRule['before_text']}")
                                content = content.replace(
                                    insertRule['before_text'], 
                                    insertRule['insert_text'] + insertRule['before_text']
                                )

                            if 'old_text' in insertRule:
                                print(f"  Replacing text: {insertRule['old_text']} -> {insertRule['new_text']}")
                                content = content.replace(
                                    insertRule['old_text'], 
                                    insertRule['new_text']
                                )

                        # Write modified contents
                        with open(filePath, 'w', encoding='utf-8') as f:
                            f.write(content)

                        results['modifications'] += 1
                except PermissionError:
                    print(f"Error: Permission denied when modifying {filePath}")
                except IOError as e:
                    print(f"Error reading/writing file {filePath}: {e}")

    print("File modification process completed.")


def main():
    """Main function to execute all operations."""
    # Check command-line argument
    if len(sys.argv) < 2:
        print("Please provide the path to the configuration file.")
        sys.exit(1)

    configPath = sys.argv[1]
    
    # Load configuration
    config = loadConfig(configPath)
    
    # Initialize results
    results = {"copies": 0, "modifications": 0}

    # Ensure destination directory
    destinationDirectory = config.get('destination_directory', './web')
    ensureDirectory(destinationDirectory)
    
    # Copy files and folders
    copySources(config, destinationDirectory, results)
    
    # Modify files
    modifyFiles(config, destinationDirectory, results)

    # Print results
    print(f'\nTotal successful copies: {results["copies"]}')
    print(f'Total file modifications: {results["modifications"]}')
    print(f"All operations in {destinationDirectory} completed successfully.")


if __name__ == '__main__':
    main()