#!/usr/bin/env python
#
# Copyright 2008
# Steve 'Ashcrow' Milner <smilner+buildbot@redhat.com>
#
# This software may be freely redistributed under the terms of the GNU
# general public license.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.


import os
import sys

"""
Generates changelog information using git.
"""

__docformat__ = 'restructuredtext'


def print_err(msg):
    """
    Wrapper to make printing to stderr nicer.

    :Parameters:
       - `msg`: the message to print.
    """
    sys.stderr.write(msg)
    sys.stderr.write('\n')


def usage():
    """
    Prints out usage information to stderr.
    """
    print_err(f'Usage: {sys.argv[0]} git-binary since')
    print_err(f'Example: {sys.argv[0]} /usr/bin/git f5067523dfae9c7cdefc82' '8721ec593ac7be62db')


def main(args):
    """
    Main entry point.

    :Parameters:
       - `args`: same as sys.argv[1:]
    """
    # Make sure we have the arguments we need, else show usage
    try:
        git_bin = args[0]
        since = args[1]
    except IndexError:
        usage()
        return 1

    if not os.access(git_bin, os.X_OK):
        print_err(f'Can not access {git_bin}')
        return 1

    # Open a pipe and force the format
    pipe = os.popen(git_bin + ' log --pretty="format:%ad  %ae%n' '  * %s" ' + since + '..')
    print(pipe.read())
    pipe.close()
    return 0


if __name__ == '__main__':
    raise SystemExit(main(sys.argv[1:]))
