import os
import subprocess
import requests
import logging
from logging.handlers import RotatingFileHandler

logger = logging.getLogger("gh-mirror.py")
logfile = os.path.join(os.path.dirname(__file__), "logs", "gh-mirror.log")

logdir = os.path.dirname(logfile)
if not os.path.exists(logdir):
    os.makedirs(logdir)

logging.basicConfig(
    level=logging.INFO,
    format='%(asctime)s - %(levelname)s - %(message)s',
    handlers=[
        logging.StreamHandler(),
        RotatingFileHandler(filename=logfile,
                            maxBytes=512000,
                            backupCount=4)
    ]
)

def load_dotenv(dotenv_file='.env'):
    try:
        with open(dotenv_file) as f:
            for line in f:
                line = line.strip()
                if not line or line.startswith('#'):
                    continue
                key, value = line.split('=', 1)
                os.environ[key] = value
    except FileNotFoundError:
        logging.error(f"Error: '{dotenv_file}' file not found.")

def run_command(command):
    try:
        return subprocess.check_output(command, stderr=subprocess.STDOUT, shell=True, universal_newlines=True)
    except subprocess.CalledProcessError as e:
        logging.error(f"Command '{e.cmd}' returned non-zero exit status {e.returncode}. Output:\n{e.output}")

def get_github_repos(github_username, github_token):
    """Fetch a list of all GitHub repositories for the authenticated user with pagination."""
    repos = []
    page = 1
    while True:
        url = f"https://api.github.com/user/repos?visibility=all&per_page=100&page={page}"
        headers = {'Authorization': f'token {github_token}'}
        response = requests.get(url, headers=headers)
        if response.status_code == 200:
            page_repos = response.json()
            if not page_repos:
                break  # No more repositories to fetch
            repos.extend([repo for repo in page_repos if repo['owner']['login'] == github_username])
            page += 1
        else:
            logging.error(f"Failed to fetch GitHub repos (HTTP status: {response.status_code}).")
            break
    return repos

def create_gitlab_repo(gitlab_token, repo_name, gitlab_group_id):
    headers = {'PRIVATE-TOKEN': gitlab_token}
    data = {'name': repo_name, 'namespace_id': gitlab_group_id}
    response = requests.post('https://gitlab.com/api/v4/projects', headers=headers, data=data)
    return response.status_code

def mirror_repo_to_gitlab(github_username, repo_name, gitlab_group_name):
    run_command(f'git clone --mirror git@github.com:{github_username}/{repo_name}.git {repo_name}')
    os.chdir(repo_name)
    run_command(f'git remote add gitlab git@gitlab.com:{gitlab_group_name}/{repo_name}.git')
    run_command('git config --local --replace remote.origin.fetch "+refs/heads/*:refs/heads/*"')
    run_command('git config --local --add remote.origin.fetch "+refs/tags/*:refs/tags/*"')
    run_command('git config --local --add remote.origin.fetch "+refs/change/*:refs/change/*"')
    run_command('git config --local --replace remote.gitlab.push "+refs/heads/*:refs/heads/*"')
    run_command('git config --local --add remote.gitlab.push "+refs/tags/*:refs/tags/*"')
    run_command('git config --local --add remote.gitlab.push "+refs/change/*:refs/change/*"')
    run_command('git push --mirror gitlab')
    os.chdir('..')
    run_command(f'rm -rf {repo_name}')

def main():
    load_dotenv()

    github_username = os.environ.get('GITHUB_USERNAME', 'Github username not set')
    # gitlab_username = os.environ.get('GITLAB_USERNAME', 'GitLab username not set')
    github_token = os.environ.get('GITHUB_TOKEN', 'GitHub token not set')
    gitlab_token = os.environ.get('GITLAB_TOKEN', 'GitLab token not set')
    gitlab_group_id = os.environ.get('GITLAB_GROUP_ID', 'GitLab group ID not set')
    gitlab_group_name = os.environ.get('GITLAB_GROUP_NAME', 'GitLab group name not')

    repos = get_github_repos(github_username, github_token)
    logging.info(f"Found {len(repos)} repositories on GitHub")
    for repo in repos:
        repo_name = repo['name']
        logging.info(f"Mirroring {repo_name}")
        status = create_gitlab_repo(gitlab_token, repo_name, gitlab_group_id)
        if status == 201:
            logging.debug(f"Repository {repo_name} created on GitLab")
        elif status == 400:
            logging.debug(f"Repository {repo_name} already exists on GitLab")
        else:
            logging.error(f"An unexpected error occurred while creating {repo_name} on GitLab (HTTP status: {status}).")
            continue
        mirror_repo_to_gitlab(github_username, repo_name, gitlab_group_name)


if __name__ == '__main__':
    main()