#! /usr/bin/env python3
#                          __  __            _
#                       ___\ \/ /_ __   __ _| |_
#                      / _ \\  /| '_ \ / _` | __|
#                     |  __//  \| |_) | (_| | |_
#                      \___/_/\_\ .__/ \__,_|\__|
#                               |_| XML parser
#
# Copyright (c) 2017 Rhodri James <rhodri@wildebeest.org.uk>
# Copyright (c) 2017 Sebastian Pipping <sebastian@pipping.org>
# Licensed under the MIT license:
#
# Permission is  hereby granted,  free of charge,  to any  person obtaining
# a  copy  of  this  software   and  associated  documentation  files  (the
# "Software"),  to  deal in  the  Software  without restriction,  including
# without  limitation the  rights  to use,  copy,  modify, merge,  publish,
# distribute, sublicense, and/or sell copies of the Software, and to permit
# persons  to whom  the Software  is  furnished to  do so,  subject to  the
# following conditions:
#
# The above copyright  notice and this permission notice  shall be included
# in all copies or substantial portions of the Software.
#
# THE  SOFTWARE  IS  PROVIDED  "AS  IS",  WITHOUT  WARRANTY  OF  ANY  KIND,
# EXPRESS  OR IMPLIED,  INCLUDING  BUT  NOT LIMITED  TO  THE WARRANTIES  OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
# NO EVENT SHALL THE AUTHORS OR  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
# DAMAGES OR  OTHER LIABILITY, WHETHER  IN AN  ACTION OF CONTRACT,  TORT OR
# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
# USE OR OTHER DEALINGS IN THE SOFTWARE.

import argparse
import difflib
import sys


def _read_lines(filename):
    try:
        with open(filename) as f:
            return f.readlines()
    except UnicodeDecodeError:
        with open(filename, encoding='utf_16') as f:
            return f.readlines()


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('first', metavar='FILE')
    parser.add_argument('second', metavar='FILE')
    config = parser.parse_args()

    first = _read_lines(config.first)
    second = _read_lines(config.second)

    diffs = list(difflib.unified_diff(first, second, fromfile=config.first,
                                      tofile=config.second))
    if diffs:
        sys.stdout.writelines(diffs)
        sys.exit(1)


if __name__ == '__main__':
    main()