#!/usr/bin/env python3
import argparse
import base64
import hashlib
import importlib.resources
import io
import os.path
import shutil
import subprocess
import tempfile
import zipapp
import zipfile

HERE = os.path.dirname(os.path.realpath(__file__))
IMG = 'make-pre-commit-zipapp'


def _msg(s: str) -> None:
    print(f'\033[7m{s}\033[m')


def _exit_if_retv(*cmd: str) -> None:
    if subprocess.call(cmd):
        raise SystemExit(1)


def _check_no_shared_objects(wheeldir: str) -> None:
    for zip_filename in os.listdir(wheeldir):
        with zipfile.ZipFile(os.path.join(wheeldir, zip_filename)) as zipf:
            for filename in zipf.namelist():
                if filename.endswith('.so') or '.so.' in filename:
                    raise AssertionError(zip_filename, filename)


def _add_shim(dest: str) -> None:
    shim = os.path.join(HERE, 'python')
    shutil.copy(shim, dest)

    bio = io.BytesIO()
    with zipfile.ZipFile(bio, 'w') as zipf:
        zipf.write(shim, arcname='__main__.py')

    with open(os.path.join(dest, 'python.exe'), 'wb') as f:
        f.write(importlib.resources.read_binary('distlib', 't32.exe'))
        f.write(b'#!py.exe -3\n')
        f.write(bio.getvalue())


def _write_cache_key(version: str, wheeldir: str, dest: str) -> None:
    cache_hash = hashlib.sha256(f'{version}\n'.encode())
    for filename in sorted(os.listdir(wheeldir)):
        cache_hash.update(f'{filename}\n'.encode())
    with open(os.path.join(HERE, 'python'), 'rb') as f:
        cache_hash.update(f.read())
    with open(os.path.join(dest, 'CACHE_KEY'), 'wb') as f:
        f.write(base64.urlsafe_b64encode(cache_hash.digest()).rstrip(b'='))


def main() -> int:
    parser = argparse.ArgumentParser()
    parser.add_argument('version')
    args = parser.parse_args()

    with tempfile.TemporaryDirectory() as tmpdir:
        wheeldir = os.path.join(tmpdir, 'wheels')
        os.mkdir(wheeldir)

        _msg('building podman image...')
        _exit_if_retv('podman', 'build', '-q', '-t', IMG, HERE)

        _msg('populating wheels...')
        _exit_if_retv(
            'podman', 'run', '--rm', '--volume', f'{wheeldir}:/wheels:rw', IMG,
            'pip', 'wheel', f'pre_commit=={args.version}',
            '--wheel-dir', '/wheels',
        )

        _msg('validating wheels...')
        _check_no_shared_objects(wheeldir)

        _msg('adding __main__.py...')
        mainfile = os.path.join(tmpdir, '__main__.py')
        shutil.copy(os.path.join(HERE, 'entry'), mainfile)

        _msg('adding shim...')
        _add_shim(tmpdir)

        _msg('copying file_lock.py...')
        file_lock_py = os.path.join(HERE, '../../pre_commit/file_lock.py')
        file_lock_py_dest = os.path.join(tmpdir, 'pre_commit/file_lock.py')
        os.makedirs(os.path.dirname(file_lock_py_dest))
        shutil.copy(file_lock_py, file_lock_py_dest)

        _msg('writing CACHE_KEY...')
        _write_cache_key(args.version, wheeldir, tmpdir)

        filename = f'pre-commit-{args.version}.pyz'
        _msg(f'writing {filename}...')
        shebang = '/usr/bin/env python3'
        zipapp.create_archive(tmpdir, filename, interpreter=shebang)

    return 0


if __name__ == '__main__':
    exit(main())