import os
import sys
from huggingface_hub import hf_hub_download
import traceback

def load_script(file_str: str):
    """
    Downloads a file from the Hugging Face Hub and ensures a symlink exists in the current directory.

    Parameters:
    - file_str (str): Path in the format 'repo_id/[subfolder]/filename', e.g., 'myorg/myrepo/mysubfolder/myscript.py'

    Returns:
    - str: The path to the downloaded file.
    """
    try:
        # Split the path by "/"
        parts = file_str.strip().split("/")
        
        if len(parts) < 2:
            raise ValueError(
                f"Invalid file specification '{file_str}'. "
                f"Expected format: 'repo_id/[subfolder]/filename'"
            )
        
        # First two parts form the repo_id (e.g., 'myorg/myrepo')
        repo_id = "/".join(parts[:2])
        
        # Last part is the actual filename (e.g., 'myscript.py')
        filename = parts[-1]
        
        # Anything between the second and last parts is a subfolder path
        subfolder = "/".join(parts[2:-1]) if len(parts) > 3 else None

        # Retrieve HF token from environment
        hf_token = os.getenv("HF_TOKEN", None)
        if not hf_token:
            print("Warning: 'HF_TOKEN' environment variable not set. Proceeding without authentication.")

        # Download the file into current directory "."
        file_path = hf_hub_download(
            repo_id=repo_id,
            filename=filename,
            subfolder=subfolder,
            repo_type="space",
            token=hf_token,
            local_dir=".",  # Download into the current directory
            force_download=True,
        )
        
        print(f"Downloaded '{filename}' from '{repo_id}' to '{file_path}'")

        # Absolute paths for comparison
        current_dir = os.path.abspath(".")
        downloaded_file_abs = os.path.abspath(file_path)
        downloaded_dir_abs = os.path.dirname(downloaded_file_abs)

        # If the file is not in the current directory, create a symlink
        if downloaded_dir_abs != current_dir:
            symlink_path = os.path.join(current_dir, filename)
            
            # If symlink exists, remove it
            if os.path.islink(symlink_path) or os.path.exists(symlink_path):
                try:
                    os.remove(symlink_path)
                    print(f"Removed existing link or file: '{symlink_path}'")
                except Exception as e:
                    print(f"Error removing existing link '{symlink_path}': {e}")
                    return file_path  # Return the actual file path even if symlink fails
            
            # Create a relative symlink
            relative_target = os.path.relpath(downloaded_file_abs, current_dir)
            try:
                os.symlink(relative_target, symlink_path)
                print(f"Created symlink: '{symlink_path}' -> '{relative_target}'")
            except OSError as e:
                print(f"Failed to create symlink for '{filename}': {e}")
                # On Windows, creating symlinks may require admin privileges
                # Alternatively, you can copy the file instead of linking
                # Uncomment the following lines to copy the file if symlink fails
                # import shutil
                # try:
                #     shutil.copy2(downloaded_file_abs, symlink_path)
                #     print(f"Copied '{filename}' to '{symlink_path}'")
                # except Exception as copy_e:
                #     print(f"Failed to copy file for '{filename}': {copy_e}")
            
        return file_path

    except Exception as e:
        print(f"Error downloading the script '{file_str}': {e}")
        return None


def load_scripts():
    """
    Downloads and executes scripts based on a file list from the Hugging Face Hub.

    Steps:
    1. Retrieve the 'FILE_LIST' environment variable, which specifies the file list path.
    2. Download the file list using `load_script()`.
    3. Read each line from the downloaded file list, where each line specifies another file to download.
    4. After downloading all files, execute the last downloaded file.
    """
    file_list = os.getenv("FILE_LIST", "").strip()
    if not file_list:
        print("No 'FILE_LIST' environment variable set. Nothing to download.")
        return

    print(f"FILE_LIST: '{file_list}'")

    # Step 1: Download the file list itself
    file_list_path = load_script(file_list)
    if not file_list_path or not os.path.exists(file_list_path):
        print(f"Could not download or find file list: '{file_list_path}'")
        return

    # Step 2: Read each line in the downloaded file list
    try:
        with open(file_list_path, 'r') as f:
            lines = [line.strip() for line in f if line.strip()]
        print(f"Found {len(lines)} files to download from the file list.")
    except Exception as e:
        print(f"Error reading file list '{file_list_path}': {e}")
        return

    # Step 3: Download each file from the lines
    downloaded_files = []
    for idx, file_str in enumerate(lines, start=1):
        print(f"Downloading file {idx}/{len(lines)}: '{file_str}'")
        file_path = load_script(file_str)
        if file_path:
            downloaded_files.append(file_path)

    # Step 4: Execute the last downloaded file
    if downloaded_files:
        last_file_path = downloaded_files[-1]
        print(f"Executing the last downloaded script: '{last_file_path}'")
        try:
            with open(last_file_path, 'r') as f:
                script_content = f.read()
            globals_dict = globals()
            globals_dict['__name__'] = '__main__'
            exec(script_content, globals_dict)
            print(f"Successfully executed '{last_file_path}'")
        except Exception as e:
            print(f"Error executing the last downloaded script '{last_file_path}': {e}")
            print(traceback.format_exc())
    else:
        print("No files were downloaded to execute.")



load_scripts()