# General Utility functions.
# Copyright (C) 2019-2020 Free Software Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import sys
import os

class DebugUtil:
    debug = False
    def __init__(self, debug):
        self.debug = debug

    def eprint(self, *args, **kwargs):
        ''' Print to stderr.
        '''
        print(*args, file=sys.stderr, **kwargs)


    def print(self, *args, **kwargs):
        ''' Convenience function to print diagnostic information in the program.
        '''
        if self.debug:
            self.eprint(*args, **kwargs)


def decode(string):
    ''' Attempt to decode a string.

    Decode a string read from the source file.  The multiple attempts are needed
    due to the presence of the page break characters and some tests in locales.
    '''
    codecs = ['utf8', 'cp1252']

    for i in codecs:
        try:
            return string.decode(i)
        except UnicodeDecodeError:
            pass

    DebugUtil.eprint('Failed to decode: %s' % string)


def analyze_diff(filename, oldfile, newfile, frontends):
    ''' Parse the output of the old and new files and print the difference.

    For input files OLDFILE and NEWFILE with name FILENAME, generate reduced
    trees for them and compare them.  We limit our comparison to only C source
    files.
    '''
    name, ext = os.path.splitext(filename)

    if not ext in frontends.keys():
        return None
    else:
        frontend = frontends[ext]
        frontend.compare(oldfile, newfile)
