import base64
import shutil
import subprocess
from pathlib import Path
from typing import Optional, Iterable, Tuple


def gen_cloud_config(name: str,
                     cloud_init_path: Path,
                     wireguard_config: str,
                     ssh_authorized_keys: Optional[Iterable[str]] = None
                     ) -> Tuple[Path, Path]:
    if ssh_authorized_keys is not None:
        ssh_keys = 'ssh_authorized_keys\n' + \
                   '\n'.join((f'- {key}' for key in ssh_authorized_keys))
    else:
        ssh_keys = ''

    user_data = f"""
#cloud-config
chpasswd: {{ expire: False }}
password: root
{ssh_keys}
ssh_pwauth: False
timezone: Europe/Berlin
users:
- default

package_update: true
packages:
- wireguard

write_files:
- encoding: b64
  content: {base64.b64encode(wireguard_config.encode())}
  owner: root:root
  path: /etc/wireguard/wg0.conf
  permissions: 0600
    """

    meta_data = f"""
local-hostname: {name}    
    """

    user_data_path = cloud_init_path / 'user_data'
    meta_data_path = cloud_init_path / 'meta_data'

    with open(user_data_path, 'w+') as handle:
        handle.write(user_data)
    with open(meta_data_path, 'w+') as handle:
        handle.write(meta_data)

    return user_data_path, meta_data_path


def _gen_cloudinit_iso_image(path: Path, user_data_path: Path, meta_data_path: Path, volume_label: str = 'cloud_init'):
    genisoimage_executable = shutil.which('genisoimage')
    if genisoimage_executable is None:
        raise FileNotFoundError('could not locate genisoimage executable!')

    command = (
        genisoimage_executable,
        '-output', str(path),
        '-V', volume_label,
        '-r',
        '-J',
        user_data_path,
        meta_data_path
    )

    try:
        subprocess.run(
            command,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE,
            check=True
        )
    except subprocess.CalledProcessError as ex:
        print(f'genisoimage error, stderr was: {ex.stderr}, stdout was: {ex.stdout}')
        raise ex