#!/usr/bin/env python
# -*- coding: utf-8 -*-

import json
import os
import subprocess
import sys


def main():

    if (len(sys.argv) != 2):
        sys.exit('Invalid parameter. Usage: {0} <mapping>\n'.format(
            sys.argv[0]))
    cstm_error = ''
    try:
        cstm_error = 'Could not open config (~/.cmount.json)'
        with open(os.path.expanduser('~/.cmount.json')) as fp:
            config_dict = json.load(fp)
        cstm_error = 'Invalid / nonexistent mapping: {0}'.format(sys.argv[1])
        data = config_dict[sys.argv[1]]
        if data.get('type') == 'lvm':
            if not isinstance(data.get('pv_sources'), dict):
                cstm_error = 'Invalid config for lvm-type'
                raise Exception()
            cstm_error = 'umount error'
            subprocess.check_call(['/bin/umount',
                                   data['device']])
            cstm_error = 'lvchange error'
            subprocess.check_call(['/sbin/lvchange',
                                   '-a',
                                   'n',
                                   data['device']])
            cstm_error = 'vgexport error'
            subprocess.check_call(['/sbin/vgexport',
                                   data['device'].split('/')[2]])
            cstm_error = 'pv_sources error'
            for mapper_name in data['pv_sources'].values():
                subprocess.check_call(['/sbin/cryptsetup',
                                       'luksClose',
                                       mapper_name])
        else:
            subprocess.check_call(['/bin/umount',
                                   '/dev/mapper/' + data['mapper_name']])
            subprocess.check_call(['/sbin/cryptsetup',
                                   'luksClose',
                                   data['mapper_name']])
            if data.get('type') == 'efile':
                cstm_error = 'Unable to destroy loop device'
                loop_device = subprocess.check_output(['/usr/sbin/losetup',
                                                       '--associated',
                                                       data['device']])
                loop_device = loop_device.split(':')[0]
                subprocess.check_call(['/usr/sbin/losetup',
                                       '-d',
                                       loop_device])
    except subprocess.CalledProcessError as e:
        print('Execution error: {0}\n'.format(e), file=sys.stderr, flush=True)
    except Exception:
        print('Error: {0}\n'.format(cstm_error), file=sys.stderr, flush=True)


if __name__ == '__main__':
    main()