#!/usr/bin/env python3
import logging
import sys
import importlib
import argparse
import multiprocessing as mp

from uncloud import UncloudException
from contextlib import suppress

# the components that use etcd
ETCD_COMPONENTS= ['api',
                  'scheduler',
                  'host',
                  'filescanner',
                  'imagescanner',
                  'metadata',
                  'configure' ]

ALL_COMPONENTS = ETCD_COMPONENTS.copy()
ALL_COMPONENTS.append('cli')

def exception_hook(exc_type, exc_value, exc_traceback):
    logging.getLogger(__name__).error(
        'Uncaught exception',
        exc_info=(exc_type, exc_value, exc_traceback)
    )


sys.excepthook = exception_hook

if __name__ == '__main__':
    # Setting up root logger
    logger = logging.getLogger()
    logger.setLevel(logging.DEBUG)

    arg_parser = argparse.ArgumentParser()
    subparsers = arg_parser.add_subparsers(dest='command')

    parent_parser = argparse.ArgumentParser(add_help=False)
    parent_parser.add_argument('--debug', '-d', action='store_true', default=False,
                               help='More verbose logging')

    etcd_parser = argparse.ArgumentParser(add_help=False)
    etcd_parser.add_argument('--etcd-host')
    etcd_parser.add_argument('--etcd-port')
    etcd_parser.add_argument('--etcd-ca-cert',
                             help="CA that signed the etcd certificate")
    etcd_parser.add_argument('--etcd-cert-cert',
                             help="Path to client certificate")
    etcd_parser.add_argument('--etcd-cert-key',
                             help="Path to client certificate key")

    for component in ALL_COMPONENTS:
        mod = importlib.import_module('uncloud.{}.main'.format(component))
        parser = getattr(mod, 'arg_parser')

        if component in ETCD_COMPONENTS:
            subparsers.add_parser(name=parser.prog, parents=[parser, parent_parser, etcd_parser])
        else:
            subparsers.add_parser(name=parser.prog, parents=[parser, parent_parser])


    args = arg_parser.parse_args()
    if not args.command:
        arg_parser.print_help()
    else:
        # if we start etcd in seperate process with default settings
        # i.e inheriting few things from parent process etcd3 module
        # errors out, so the following command configure multiprocessing
        # module to not inherit anything from parent.
        # mp.set_start_method('spawn')
        arguments = vars(args)
        name = arguments.pop('command')
        mod = importlib.import_module('uncloud.{}.main'.format(name))
        main = getattr(mod, 'main')

        # If the component requires etcd3, we import it and catch the
        # etcd3.exceptions.ConnectionFailedError
        if name in ETCD_COMPONENTS:
            import etcd3

        try:
            main(arguments)
        except UncloudException as err:
            logger.error(err)
            sys.exit(1)
        except etcd3.exceptions.ConnectionFailedError as err:
            logger.error("Cannot connect to etcd")
        except Exception as err:
            logger.exception(err)
            sys.exit(1)