"""
Standalone script for writing release doc and logs::

    python tools/write_release_and_log.py <LOG_START> <LOG_END>

Example::

    python tools/write_release_and_log.py v1.7.0 v1.8.0

Needs to be run from the root of the repository.

"""

import os
import sys
import subprocess
from hashlib import md5
from hashlib import sha256
from pathlib import Path


try:
    # Ensure sensible file permissions
    os.umask(0o022)
except AttributeError:
    # No umask on non-posix
    pass


def get_latest_release_doc(path):
    """
    Method to pick the file from 'doc/release' with the highest
    release number (e.g., `1.9.0-notes.rst`).
    """
    file_paths = os.listdir(path)
    file_paths.sort(key=lambda x: list(map(int, (x.split('-')[0].split('.')))))
    return os.path.join(path, file_paths[-1])


# ----------------------------
# Release notes and Changelog
# ----------------------------


def compute_md5(idirs):
    released = os.listdir(idirs)
    checksums = []
    for fn in sorted(released):
        fn_updated = os.path.join("release", fn)
        with open(fn_updated, 'rb') as f:
            m = md5(f.read())
        checksums.append(f'{m.hexdigest()}  {os.path.basename(fn)}')
    return checksums


def compute_sha256(idirs):
    # better checksum so gpg signed README.txt containing the sums can be used
    # to verify the binaries instead of signing all binaries
    released = os.listdir(idirs)
    checksums = []
    for fn in sorted(released):
        fn_updated = os.path.join("release", fn)
        with open(fn_updated, 'rb') as f:
            m = sha256(f.read())
        checksums.append(f'{m.hexdigest()}  {os.path.basename(fn)}')

    return checksums


def write_release_task(filename='NOTES.txt'):
    idirs = Path('release')
    source = Path(get_latest_release_doc('doc/source/release'))
    target = Path(filename)
    if target.exists():
        target.remove()

    tmp_target = Path(filename + '.txt')
    os.system(f'cp {source} {tmp_target}')

    with open(str(tmp_target), 'a') as ftarget:
        ftarget.writelines("""
Checksums
=========

MD5
~~~

""")
        ftarget.writelines([f'{c}\n' for c in compute_md5(idirs)])
        ftarget.writelines("""
SHA256
~~~~~~

""")
        ftarget.writelines([f'{c}\n' for c in compute_sha256(idirs)])
        print("Release README generated successfully")


def write_log_task(filename='Changelog'):
    st = subprocess.Popen(
        ['git', 'log', f'{LOG_START}..{LOG_END}'],
        stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    output, error = st.communicate()
    if not st.returncode == 0:
        raise RuntimeError(f"{error} failed")

    out = st.communicate()[0].decode()
    with open(filename, 'w') as a:
        a.writelines(out)

    print("Release logs generated successfully")


def main():
    """
    Checks weather release directory is present or not
    and calls the method to generate logs and notes
    """
    if not os.path.exists("release"):
        os.makedirs("release")

    write_release_task(os.path.join("release", 'README'))
    write_log_task(os.path.join("release", 'Changelog'))


if __name__ == '__main__':
    if len(sys.argv) == 3:
        LOG_START = str(sys.argv[1])
        LOG_END = str(sys.argv[2])
    else:
        print("invalid number of arguments, please add LOG_START and LOG_END")

    main()