import argparse
import os
import pkg_resources
import posix
import sys

VERSION = '0.1'


class AdminCommand(object):
    def _setup_argparser(self):
        kwargs = {
            'description': 'Tool to manage the DAV Events django project installation.',
            'epilog': 'Off Belay.',
        }
        parser = argparse.ArgumentParser(**kwargs)

        parser.add_argument('-V', '--version', action='version',
                            version='%(prog)s ' + VERSION)

        subparsers = parser.add_subparsers(dest='subcmd', metavar='CMD',
                                           title='subcommands',
                                           description="Use '%(prog)s CMD -h' to show help for a subcommand")
        subparser = subparsers.add_parser('setup', help='Setup the installation.')
        subparser.add_argument('path', metavar='PATH',
                               help='A directory, where the project files will be installed.')

        return parser

    def _parse_args(self, argv=None):
        if argv is None:
            argv = sys.argv[1:]
        if not argv:
            argv = ['--help']

        return self._argparser.parse_args(argv)

    def _subcmd_setup(self, cmd_args):
        django_project_name = 'main'
        django_project_path = cmd_args.path
        
        sys.stdout.write('Setup installation in \'{path}\'...\n'.format(path=django_project_path))

        if os.path.exists(django_project_path):
            if not os.path.isdir(django_project_path):
                sys.stderr.write('{path}: Not a directory.\n'.format(path=django_project_path))
                return posix.EX_USAGE
        else:
            os.makedirs(django_project_path)

        sys.stdout.write('Creating django project...\n')
        django_cmd = 'django-admin startproject {name} "{path}"'.format(name=django_project_name,
                                                                        path=django_project_path)
        exitval = os.system(django_cmd)
        if exitval != posix.EX_OK:
            return exitval

        sys.stdout.write('Creating directories...\n')
        dirs = [
            os.path.join(django_project_path, 'var', 'db'),
            os.path.join(django_project_path, 'var', 'log'),
            os.path.join(django_project_path, 'var', 'www', 'static'),
        ]

        for d in dirs:
            sys.stdout.write('  - %s\n' % d)
            os.makedirs(d)

        sys.stdout.write('Configure django project...\n')

        input_file = os.path.join('Resources', 'django.main.additional_settings.py')
        output_file = os.path.join(django_project_path, django_project_name, 'settings.py')
        with open(output_file, 'a') as f:
            f.write(pkg_resources.resource_string(__package__, input_file))

        input_file = os.path.join('Resources', 'django.main.urls.py')
        output_file = os.path.join(django_project_path, django_project_name, 'urls.py')
        with open(output_file, 'w') as f:
            f.write(pkg_resources.resource_string(__package__, input_file))

        return posix.EX_OK

    def __init__(self):
        self._argparser = self._setup_argparser()

    def __call__(self, argv=None):
        cmd_args = self._parse_args(argv)
        subcmd = cmd_args.subcmd
        method_name = '_subcmd_{}'.format(subcmd)
        method = getattr(self, method_name)
        exitval = method(cmd_args)
        return exitval


def main():
    cmd = AdminCommand()
    exitval = cmd()
    sys.exit(exitval)