#!/usr/bin/python
# Copyright (C) 2013  Codethink Limited
#
# 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; version 2 of the License.
#
# 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, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

''' A Morph configuration extension for removing gplv3 chunks from a system

Using a hard-coded list of chunks, it will read the system's /baserock metadata
to find the files created by that chunk, then remove them.

'''

import cliapp
import os
import json

class StripGPLv3ConfigureExtension(cliapp.Application):
    gplv3_chunks = ['autoconf', 'automake', 'bash', 'binutils', 'bison', 'ccache', 'cmake',
                    'flex', 'gawk', 'gdbm', 'gettext', 'gperf', 'groff', 'libtool', 'm4',
                    'make', 'nano', 'texinfo-tarball']

    def process_args(self, args):
        target_root = args[0]

        for chunk in self.gplv3_chunks:
            self.remove_chunk(target_root, chunk)

    def remove_chunk(self, target_root, chunk):
        chunk_meta_path = os.path.join(target_root, 'baserock',
                                       chunk + '.meta')

        with open(chunk_meta_path, 'r') as f:
            chunk_meta_data = json.load(f)

        if not 'contents' in chunk_meta_data:
            raise cliapp.AppError('Chunk %s does not have a "contents" list'
                                  % chunk)
        for content_entry in reversed(chunk_meta_data['contents']):
            self.remove_content_entry(target_root, content_entry)

        os.remove(chunk_meta_path)

    def remove_content_entry(self, target_root, content_entry):
        entry_path = os.path.join(target_root, './' + content_entry)
        if not entry_path.startswith(target_root):
            raise cliapp.AppException('%s is not in %s'
                                      % (entry_path, target_root))
        if os.path.exists(entry_path):
            if os.path.islink(entry_path):
                os.unlink(entry_path)
            elif os.path.isfile(entry_path):
                os.remove(entry_path)
            elif os.path.isdir(entry_path):
                if not os.listdir(entry_path):
                    os.rmdir(entry_path)
            else:
                raise cliapp.AppException('%s is not a link, file or directory'
                                          % entry_path)
StripGPLv3ConfigureExtension().run()