import os
import re
import sys
import yaml

def load_configuration(config_path):
    """
    Load configuration from a YAML file.
    
    :param config_path: Path to the configuration file
    :return: Loaded configuration dictionary
    """
    with open(config_path, 'r', encoding='utf-8') as config_file:
        return yaml.safe_load(config_file)

def matches_file_pattern(filename, pattern):
    """
    Check if filename matches the given pattern.
    
    :param filename: Name of the file
    :param pattern: Regex pattern to match
    :return: Boolean indicating if filename matches
    """
    return re.search(pattern, filename) is not None

def apply_insert_rules(content, insert_rules):
    """
    Apply insertion rules to the content.
    
    :param content: Original file content
    :param insert_rules: List of insertion rules
    :return: Modified content and modification flag
    """
    modified_content = content
    modified = False

    for rule in insert_rules:
        insert_text = rule.get('insert_text')
        
        # Insert after specific text
        if 'after_text' in rule:
            search_text = rule.get('after_text')
            if insert_text not in modified_content:
                modified_content = modified_content.replace(
                    search_text, 
                    f'{search_text}\n{insert_text}'
                )
                modified = True
        
        # Insert before specific text
        elif 'before_text' in rule:
            search_text = rule.get('before_text')
            if insert_text not in modified_content:
                modified_content = modified_content.replace(
                    search_text, 
                    f'{insert_text}\n{search_text}'
                )
                modified = True

    return modified_content, modified

def apply_replace_rules(content, replace_rules):
    """
    Apply replacement rules to the content.
    
    :param content: Original file content
    :param replace_rules: List of replacement rules
    :return: Modified content and modification flag
    """
    modified_content = content
    modified = False

    for rule in replace_rules:
        old_text = rule.get('old_text')
        new_text = rule.get('new_text')
        
        # Replace text if found
        if old_text in modified_content:
            modified_content = modified_content.replace(old_text, new_text)
            modified = True

    return modified_content, modified

def modify_files(config):
    """
    Modify files based on configuration rules.
    
    :param config: Configuration dictionary
    :return: Number of modified files
    """
    files_modified = 0
    start_directory = config.get('start_directory', '.')

    # Process each modification entry
    for entry in config.get('modifications', []):
        search_pattern = entry.get('file_pattern')
        insert_rules = entry.get('insert_rules', [])
        replace_rules = entry.get('replace_rules', [])

        # Walk through directory
        for root, _, files in os.walk(start_directory):
            for filename in files:
                # Check if file matches pattern
                if matches_file_pattern(filename, search_pattern):
                    full_path = os.path.join(root, filename)
                    
                    try:
                        # Read file content
                        with open(full_path, 'r', encoding='utf-8') as file:
                            content = file.read()
                        
                        # Apply insert rules
                        content_after_insert, insert_modified = apply_insert_rules(
                            content, insert_rules
                        )
                        
                        # Apply replace rules
                        final_content, replace_modified = apply_replace_rules(
                            content_after_insert, replace_rules
                        )
                        
                        # Save modified file
                        if insert_modified or replace_modified:
                            with open(full_path, 'w', encoding='utf-8') as file:
                                file.write(final_content)
                            
                            files_modified += 1
                            print(f'Modified: {full_path}')
                    
                    except Exception as e:
                        print(f'Error processing file {full_path}: {e}')
    
    return files_modified

def main():
    # Check command-line argument
    if len(sys.argv) < 2:
        print("Please provide the path to the configuration file.")
        sys.exit(1)
    
    config_path = sys.argv[1]
    
    # Load configuration and modify files
    config = load_configuration(config_path)
    total_modified = modify_files(config)
    
    print(f'\nTotal files modified: {total_modified}')

if __name__ == '__main__':
    main()