#!/usr/bin/python
#-*- coding: utf-8 -*-
# Copyright © 2015  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, see <http://www.gnu.org/licenses/>.


'''A Morph deployment write extension for creating images with jffs2
   as the root filesystem.'''


import os
import subprocess

import writeexts


class Jffs2WriteExtension(writeexts.WriteExtension):

    '''See jffs2.write.help for documentation.'''

    def process_args(self, args):
        if len(args) != 2:
            raise writeexts.ExtensionError('Wrong number of command line args')

        temp_root, location = args

        try:
            self.create_jffs2_system(temp_root, location)
            self.status(msg='Disk image has been created at %(location)s',
                        location=location)
        except Exception:
            self.status(msg='Failure to deploy system to %(location)s',
                        location=location)
            raise

    def create_jffs2_system(self, temp_root, location):
        erase_block = self.get_erase_block_size()
        subprocess.check_call(
            ['mkfs.jffs2', '--pad', '--no-cleanmarkers',
             '--eraseblock='+erase_block, '-d', temp_root, '-o', location])

    def get_erase_block_size(self):
        erase_block = os.environ.get('ERASE_BLOCK', '')

        if erase_block == '':
            raise writeexts.ExtensionError('ERASE_BLOCK was not given')

        if not erase_block.isdigit():
            raise writeexts.ExtensionError('ERASE_BLOCK must be a whole number')

        return erase_block

Jffs2WriteExtension().run()