# Copyright 2015 TrilioData, Inc
# All Rights Reserved.
#

"""Disklist Drive helper."""

import os

try:
    from oslo_config import cfg
except BaseException:
    from oslo.config import cfg

try:
    from oslo_utils import fileutils
except BaseException:
    from nova.openstack.common import fileutils

from nova import utils

diskfiles_drive_format = 'iso9660'
mkisofs_cmd = 'genisoimage'

# Diskfiles drives are 64mb, if we can't size to the exact size of the data
DISKFILESDRIVESIZE_BYTES = 64 * 1024

diskfilesdrive_opts = [
    cfg.StrOpt('diskfiles_drive_format',
               default='iso9660',
               help='Disk files drive format. One of iso9660 '
                    '(default) or vfat'),
    #cfg.StrOpt('mkisofs_cmd',
               #default='genisoimage',
               #help='Name and optionally path of the tool used for '
                    #'ISO image creation')
]

CONF = cfg.CONF
CONF.register_opts(diskfilesdrive_opts)


class DiskfilesDriveBuilder(object):
    def __init__(self, diskfiles):
        self.diskfiles = diskfiles

    def __enter__(self):
        return self

    def __exit__(self, exctype, excval, exctb):
        if exctype is not None:
            return False
        self.cleanup()

    def _add_file(self, basedir, path, data):
        filepath = os.path.join(basedir, path)
        dirname = os.path.dirname(filepath)
        fileutils.ensure_tree(dirname)
        with open(filepath, 'wb') as f:
            f.write(data)

    def _write_disk_files(self, basedir):
        self._add_file(basedir, "diskfiles", self.diskfiles)

    def _make_iso9660(self, path, tmpdir):
        publisher = "%(product)s %(version)s" % {
            'product': 'TrilioVault',
            'version': '1.0.'
        }

        utils.execute(CONF.mkisofs_cmd,
                      '-o', path,
                      '-ldots',
                      '-allow-lowercase',
                      '-allow-multidot',
                      '-l',
                      '-publisher',
                      publisher,
                      '-quiet',
                      '-J',
                      '-r',
                      '-V', 'diskdrives-1',
                      tmpdir,
                      attempts=1,
                      run_as_root=False)

    def make_drive(self, path):
        """Make the diskfiles drive.

        :param path: the path to place the diskfiles drive image at

        :raises ProcessExecuteError if a helper process has failed.
        """
        with utils.tempdir() as tmpdir:
            self._write_disk_files(tmpdir)

            if os.path.exists(path):
                os.remove(path)

            self._make_iso9660(path, tmpdir)

    def cleanup(self):
        pass

    def __repr__(self):
        return "<DiskfilesDriveBuilder: " + str(self.mdfiles) + ">"