#   Copyright 2013 Ben Longbons <b.r.longbons@gmail.com>
#
#   This file is part of attoconf.
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#   attoconf 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.
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#   attoconf is distributed in the hope that it will be useful,
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#   GNU General Public License for more details.
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from hashlib import md5
import os

from ..classy import ClassyProject


def calc_hash(build):
    hash = md5()
    for var, val in sorted(build.vars.items()):
        hash.update(('%s = %s\n' % (var, val)).encode(encoding = 'UTF-8', errors = 'strict'))
    return hash.hexdigest()


def add_config_hash(build):
    print('Generating a hash of config options ...')
    build.vars['CONFIG_HASH'] = calc_hash(build)


class ConfigHash(ClassyProject):
    ''' Post hook add the build hash.

        This should be run before any other post hooks.
    '''
    __slots__ = ()

    def post(self):
        self.order.insert(0, 'CONFIG_HASH')
        self.checks.append(add_config_hash)
        super(ConfigHash, self).post()