#!/usr/bin/env python3

import os

import common
import subprocess
import tarfile
import time

parser = common.get_argparse(argparse_args={
    'description': '''\
Build a guest root filesystem based on prebuilt Docker Ubuntu root filesystems.

See also:https://github.com/cirosantilli/linux-kernel-module-cheat#ubuntu-guest-setup
'''
    },
    default_args={'docker': True},
)
common.add_build_arguments(parser)
args = common.setup(parser)
container_name = 'lkmc-guest'
#common.rmrf(common.docker_build_dir)
if not args.clean:
    start_time = time.time()
    target_dir = os.path.join('/root', 'linux-kernel-module-cheat')
    os.makedirs(common.docker_build_dir, exist_ok=True)
    containers = subprocess.check_output([
            'docker',
            'ps',
            '-a',
            '--format', '{{.Names}}',
    ]).decode()
    if container_name in containers.split():
        common.run_cmd([
            'docker',
            'rm',
            container_name,
        ])
    common.run_cmd([
        'docker',
        'create',
        '--name', container_name,
        '--net',
        'host',
        '-i',
        '--privileged',
        '-t',
        '-w', target_dir,
        '-v', '{}:{}'.format(common.root_dir, target_dir),
        'ubuntu:18.04',
        'bash',
    ])
    common.run_cmd([
        'docker',
        'export',
        '-o',
        common.docker_tar_file,
        container_name,
    ])
    tar = tarfile.open(common.docker_tar_file)
    tar.extractall(common.docker_tar_dir)
    tar.close()
    # sudo not required in theory
    # https://askubuntu.com/questions/1046828/how-to-run-libguestfs-tools-tools-such-as-virt-make-fs-without-sudo
    common.run_cmd([
        'virt-make-fs',
        '--format', 'raw',
        '--size', '+1G',
        '--type', 'ext2',
        common.docker_tar_dir,
        common.docker_rootfs_raw_file,
    ])
    common.raw_to_qcow2(prebuilt=True)
    end_time = time.time()
    common.print_time(end_time - start_time)