#!/usr/bin/env python3
"""Rebuild source exports in different paths and compare release artifacts."""
import argparse
import hashlib
import os
from pathlib import Path
import subprocess
import tarfile
import tempfile


def digest(path):
    return hashlib.sha256(path.read_bytes()).hexdigest()


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument('archive', type=Path)
    parser.add_argument('--gui', action='store_true')
    parser.add_argument('--generator', default=os.environ.get('CMAKE_GENERATOR'))
    args = parser.parse_args()
    archive = args.archive.resolve()
    assert archive.with_name(archive.name + '.sha256').read_text().split()[0] == digest(archive)
    with tempfile.TemporaryDirectory(prefix='xtc-release-') as directory:
        root = Path(directory)
        with tarfile.open(archive) as source:
            names = [m.name for m in source.getmembers()]
            assert len(set(names)) == len(names)
            assert all(m.isfile() for m in source.getmembers())
            top = names[0].split('/')[0]
            epoch = source.getmembers()[0].mtime
            assert all(n.startswith(top + '/') and '..' not in Path(n).parts for n in names)
            assert all('__pycache__' not in Path(n).parts and '.git' not in Path(n).parts for n in names)
            for name in ('first', 'different-path'):
                source.extractall(root / name, filter='data')
        env = dict(os.environ, SOURCE_DATE_EPOCH=str(epoch))
        if args.generator:
            env['CMAKE_GENERATOR'] = args.generator
        builds = []
        for name in ('first', 'different-path'):
            project = root / name / top
            log = root / (name + '.log')
            with log.open('w') as output:
                try:
                    subprocess.run(['cmake', '-S', '.', '-B', 'build/release',
                                    '-DCMAKE_BUILD_TYPE=Release', '-DXTC_REPRODUCIBLE=ON',
                                    f'-DXTC_BUILD_GUI={"ON" if args.gui else "OFF"}'],
                                   cwd=project, env=env, stdout=output, stderr=subprocess.STDOUT, check=True)
                    subprocess.run(['cmake', '--build', 'build/release', '--parallel', '3'],
                                   cwd=project, env=env, stdout=output, stderr=subprocess.STDOUT, check=True)
                    subprocess.run(['ctest', '--test-dir', 'build/release', '--output-on-failure'],
                                   cwd=project, env=env, stdout=output, stderr=subprocess.STDOUT, check=True)
                except subprocess.CalledProcessError:
                    print(log.read_text()[-12000:])
                    raise
            # Exported source can package itself without a .git directory.
            repacked = root / (name + '.tar.gz')
            subprocess.run([env.get('PYTHON', 'python3'), 'tools/dist.py', '--output', str(repacked)],
                           cwd=project, env=env, check=True)
            assert digest(repacked) == digest(archive), 'Source archive is not reproducible'
            release = project / 'build/release'
            files = ['libxtc.a', 'xtc-check'] + (['xtc'] if args.gui else [])
            builds.append({file: digest(release / file) for file in files})
        assert builds[0] == builds[1], (builds[0], builds[1])
        for file, sha in builds[0].items():
            print(f'Reproducible {file}: {sha}')
    print('Two clean source-export release builds and archives are byte-identical.')


if __name__ == '__main__':
    main()