#!/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 re
import os
import json

class StripGPLv3ConfigureExtension(cliapp.Application):
    gplv3_chunks = [
        ['autoconf', ''],
        ['automake', ''],
        ['bash', ''],
        ['binutils', ''],
        ['bison', ''],
        ['ccache', ''],
        ['cmake', ''],
        ['flex', ''],
        ['gawk', ''],
        ['gcc', r'^.*lib.*\.so(\.\d+)*$'],
        ['gdbm', ''],
        ['gettext', ''],
        ['gperf', ''],
        ['groff', ''],
        ['libtool', r'^.*lib.*\.so(\.\d+)*$'],
        ['m4', ''],
        ['make', ''],
        ['nano', ''],
        ['texinfo-tarball', ''],
    ]

    def process_args(self, args):
        target_root = args[0]
        meta_dir = os.path.join(target_root, 'baserock')

        for chunk in self.gplv3_chunks:
            regex = os.path.join(meta_dir, "%s-[^-]\+\.meta" % chunk[0])
            artifacts = self.runcmd(['find', meta_dir,  '-regex', regex])

            for artifact in artifacts.split():
                self.remove_chunk(target_root, artifact, chunk[1])

        os.symlink(os.path.join(os.sep, 'bin', 'busybox'),
                   os.path.join(target_root, 'usr', 'bin', 'awk'))

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

        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)
        updated_contents = []
        for content_entry in reversed(chunk_meta_data['contents']):
            pat = re.compile(pattern)
            if len(pattern) == 0 or not pat.match(content_entry):
                self.remove_content_entry(target_root, content_entry)
            else:
                updated_contents.append(content_entry)

    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()