import os
from smolagents import tool

@tool
def codebase_inspector(action: str, target_path: str, file_content: str = "") -> str:
    """A tool to explore, read, or create/append files in the active agent repository workspace.
    
    Args:
        action: The operation to execute. Choose from: 'list_dir', 'read_file', 'write_file', or 'append_file'.
        target_path: The relative file path or directory pathway (e.g., 'tools/my_new_tool.py' or 'tools').
        file_content: Optional string containing python code or text to write/append.
    """
    try:
        # Prevent escaping the root directory for fundamental space isolation
        normalized_path = os.path.normpath(target_path)
        if normalized_path.startswith(".."):
            return "Error: Access denied. Cannot navigate outside the repository root workspace."
            
        if action == 'list_dir':
            if os.path.exists(normalized_path) and os.path.isdir(normalized_path):
                files = os.listdir(normalized_path)
                return f"Directory contents of '{normalized_path}': {str(files)}"
            return f"Error: Path '{normalized_path}' does not exist or is not a directory."
            
        elif action == 'read_file':
            if os.path.exists(normalized_path) and os.path.isfile(normalized_path):
                with open(normalized_path, 'r', encoding='utf-8') as f:
                    content = f.read()
                return f"--- START OF FILE: {normalized_path} ---\n{content}\n--- END OF FILE ---"
            return f"Error: File '{normalized_path}' not found."
            
        elif action in ['write_file', 'append_file']:
            if not file_content:
                return "Error: 'file_content' argument cannot be empty when writing or appending."
            
            # Ensure directories exist
            dir_name = os.path.dirname(normalized_path)
            if dir_name and not os.path.exists(dir_name):
                os.makedirs(dir_name, exist_ok=True)
                
            mode = 'w' if action == 'write_file' else 'a'
            with open(normalized_path, mode, encoding='utf-8') as f:
                f.write(file_content)
                
            return f"Successfully executed '{action}' on '{normalized_path}'."
            
        else:
            return f"Error: Action '{action}' is invalid. Use list_dir, read_file, write_file, or append_file."
            
    except Exception as e:
        return f"An exception occurred while operating on the codebase: {str(e)}"