#!/usr/bin/env python3

"""
Create source tarball, create rpm from it together with spec file.

Create a source tarball that is compatbile with standard build pipelines. Then
run rpmbuild on it to create an installable rpm.

.. codeauthor:: Intra2net AG <info@intra2net.com>
"""

import sys
from os.path import join, basename, dirname, expanduser
from re import compile as re_compile
import tarfile
from shutil import copy
from subprocess import run

# path to spec file
BASE_DIR = dirname(__file__)
SPEC_FILE = join(BASE_DIR, 'pyi2ncommon.spec')

# regular expressions extracting relevant information from spec file
VERSION_REGEX = re_compile(r'^Version:\s*(\S+)\s*$')
NAME_REGEX = re_compile(r'^Name:\s*(\S+)\s*$')
SOURCE_REGEX = re_compile(r'^Source0:\s*(\S+)\s*$')

# dir to contain tarball
DIST_DIR = join(BASE_DIR, 'dist')

# files and dirs to add to tarball; keep in sync with %files secion in spec
DATA = (
    'COPYING.GPL', 'Linking-Exception.txt', 'README', 'CONTRIBUTING',
    'setup.py', 'src', 'test', 'doc/about_docu.rst', 'doc/conf.py'
)

# dir where rpmbuild expects its tarballs
RPM_SOURCE_DIR = expanduser(join('~', 'rpmbuild', 'SOURCES'))


def get_spec_info():
    """Extract name, version and source0 from spec file."""
    name = None
    version = None
    source = None
    with open(SPEC_FILE, 'rt') as reader:
        for line in reader:
            if name is not None and version is not None and source is not None:
                source = source.replace('%{name}', name)\
                               .replace('%{version}', version)
                return name, version, source
            match = NAME_REGEX.match(line)
            if match:
                name = match.group(1)
                continue
            match = VERSION_REGEX.match(line)
            if match:
                version = match.group(1)
                continue
            match = SOURCE_REGEX.match(line)
            if match:
                source = match.group(1)
                continue


def tar_add_filter(tarinfo):
    """
    Filter function for adding files to tarball

    Return `None` for pycache and pyc, meaning "do not add". Return input
    otherwise to add the file.
    """
    if tarinfo.name.endswith('.pyc'):
        print(f'Skip {tarinfo.name}')
        return None
    if '__pycache__' in tarinfo.name:
        print(f'Skip {tarinfo.name}')
        return None
    print(f'Adding {tarinfo.name}')
    return tarinfo


def create_tarball():
    """Create tarball, return its full path."""
    name, version, tarball_file = get_spec_info()
    tarball_path = join(DIST_DIR, tarball_file)
    print(f'Creating {tarball_path}')
    dirname = f'{name}-{version}'
    with tarfile.open(tarball_path, 'w:gz') as tarball:
        for entry in DATA:
            tarball.add(entry, join(dirname, entry), filter=tar_add_filter)
    return tarball_path


def build_rpm(tarball_path):
    """Create rpm using rpmbuild with spec file and newly created tarball."""
    copy(tarball_path, RPM_SOURCE_DIR)
    run(('rpmbuild', '-bb', SPEC_FILE))


def main():
    """
    Main function, called when running file as script.

    See module doc for more info.
    """
    tarball_path = create_tarball()
    build_rpm(tarball_path)
    print(f'{basename(__file__)} finished successfully.')

    return 0


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