# Source code for mopidy.commands

    from __future__ import absolute_import, print_function, unicode_literals

    import argparse
    import collections
    import contextlib
    import logging
    import os
    import signal
    import sys

    import pykka

    from mopidy import config as config_lib, exceptions
    from mopidy.audio import Audio
    from mopidy.core import Core
    from mopidy.internal import deps, process, timer, versioning
    from mopidy.internal.gi import GLib

    logger = logging.getLogger(__name__)

    _default_config = []
    for base in GLib.get_system_config_dirs() + [GLib.get_user_config_dir()]:
        _default_config.append(os.path.join(base, b'mopidy', b'mopidy.conf'))
    DEFAULT_CONFIG = b':'.join(_default_config)

    def config_files_type(value):
        return value.split(b':')

    def config_override_type(value):
        try:
            section, remainder = value.split(b'/', 1)
            key, value = remainder.split(b'=', 1)
            return (section.strip(), key.strip(), value.strip())
        except ValueError:
            raise argparse.ArgumentTypeError(
                '%s must have the format section/key=value' % value)

    class _ParserError(Exception):

        def __init__(self, message):
            self.message = message

    class _HelpError(Exception):
        pass

    class _ArgumentParser(argparse.ArgumentParser):

        def error(self, message):
            raise _ParserError(message)

    class _HelpAction(argparse.Action):

        def __init__(self, option_strings, dest=None, help=None):
            super(_HelpAction, self).__init__(
                option_strings=option_strings,
                dest=dest or argparse.SUPPRESS,
                default=argparse.SUPPRESS,
                nargs=0,
                help=help)

        def __call__(self, parser, namespace, values, option_string=None):
            raise _HelpError()

    class Command(object):

        """Command parser and runner for building trees of commands.

        This class provides a wraper around :class:`argparse.ArgumentParser`
        for handling this type of command line application in a better way than
        argprases own sub-parser handling.
        """

        help = None
        #: Help text to display in help output.

        def __init__(self):
            self._children = collections.OrderedDict()
            self._arguments = []
            self._overrides = {}

        def _build(self):
            actions = []
            parser = _ArgumentParser(add_help=False)
            parser.register('action', 'help', _HelpAction)

            for args, kwargs in self._arguments:
                actions.append(parser.add_argument(*args, **kwargs))

            parser.add_argument('_args', nargs=argparse.REMAINDER,
                                help=argparse.SUPPRESS)
            return parser, actions

        def add_child(self, name, command):
            """Add a child parser to consider using.

            :param name: name to use for the sub-command that is being added.
            :type name: string
            """
            self._children[name] = command

        def add_argument(self, *args, **kwargs):
            """Add an argument to the parser.

            This method takes all the same arguments as the
            :class:`argparse.ArgumentParser` version of this method.
            """
            self._arguments.append((args, kwargs))

        def set(self, **kwargs):
            """Override a value in the finaly result of parsing."""
            self._overrides.update(kwargs)

        def exit(self, status_code=0, message=None, usage=None):
            """Optionally print a message and exit."""
            print('\n\n'.join(m for m in (usage, message) if m))
            sys.exit(status_code)

        def format_usage(self, prog=None):
            """Format usage for current parser."""
            actions = self._build()[1]
            prog = prog or os.path.basename(sys.argv[0])
            return self._usage(actions, prog) + '\n'

        def _usage(self, actions, prog):
            formatter = argparse.HelpFormatter(prog)
            formatter.add_usage(None, actions, [])
            return formatter.format_help().strip()

        def format_help(self, prog=None):
            """Format help for current parser and children."""
            actions = self._build()[1]
            prog = prog or os.path.basename(sys.argv[0])

            formatter = argparse.HelpFormatter(prog)
            formatter.add_usage(None, actions, [])

            if self.help:
                formatter.add_text(self.help)

            if actions:
                formatter.add_text('OPTIONS:')
                formatter.start_section(None)
                formatter.add_arguments(actions)
                formatter.end_section()

            subhelp = []
            for name, child in self._children.items():
                child._subhelp(name, subhelp)

            if subhelp:
                formatter.add_text('COMMANDS:')
                subhelp.insert(0, '')

            return formatter.format_help() + '\n'.join(subhelp)

        def _subhelp(self, name, result):
            actions = self._build()[1]

            if self.help or actions:
                formatter = argparse.HelpFormatter(name)
                formatter.add_usage(None, actions, [], '')
                formatter.start_section(None)
                formatter.add_text(self.help)
                formatter.start_section(None)
                formatter.add_arguments(actions)
                formatter.end_section()
                formatter.end_section()
                result.append(formatter.format_help())

            for childname, child in self._children.items():
                child._subhelp(' '.join((name, childname)), result)

        def parse(self, args, prog=None):
            """Parse command line arguments.

            Will recursively parse commands until a final parser is found or an
            error occurs. In the case of errors we will print a message and exit.
            Otherwise, any overrides are applied and the current parser stored
            in the command attribute of the return value.

            :param args: list of arguments to parse
            :type args: list of strings
            :param prog: name to use for program
            :type prog: string
            :rtype: :class:`argparse.Namespace`
            """
            prog = prog or os.path.basename(sys.argv[0])
            try:
                return self._parse(
                    args, argparse.Namespace(), self._overrides.copy(), prog)
            except _HelpError:
                self.exit(0, self.format_help(prog))

        def _parse(self, args, namespace, overrides, prog):
            overrides.update(self._overrides)
            parser, actions = self._build()

            try:
                result = parser.parse_args(args, namespace)
            except _ParserError as e:
                self.exit(1, e.message, self._usage(actions, prog))

            if not result._args:
                for attr, value in overrides.items():
                    setattr(result, attr, value)
                delattr(result, '_args')
                result.command = self
                return result

            child = result._args.pop(0)
            if child not in self._children:
                usage = self._usage(actions, prog)
                self.exit(1, 'unrecognized command: %s' % child, usage)

            return self._children[child]._parse(
                result._args, result, overrides, ' '.join([prog, child]))

        def run(self, *args, **kwargs):
            """Run the command.

            Must be implemented by sub-classes that are not simply an intermediate
            in the command namespace.
            """
            raise NotImplementedError

    @contextlib.contextmanager
    def _actor_error_handling(name):
        try:
            yield
        except exceptions.BackendError as exc:
            logger.error(
                'Backend (%s) initialization error: %s', name, exc.message)
        except exceptions.FrontendError as exc:
            logger.error(
                'Frontend (%s) initialization error: %s', name, exc.message)
        except exceptions.MixerError as exc:
            logger.error(
                'Mixer (%s) initialization error: %s', name, exc.message)
        except Exception:
            logger.exception('Got un-handled exception from %s', name)

    # TODO: move out of this utility class
    class RootCommand(Command):

        def __init__(self):
            super(RootCommand, self).__init__()
            self.set(base_verbosity_level=0)
            self.add_argument(
                '-h', '--help',
                action='help', help='Show this message and exit')
            self.add_argument(
                '--version', action='version',
                version='Mopidy %s' % versioning.get_version())
            self.add_argument(
                '-q', '--quiet',
                action='store_const', const=-1, dest='verbosity_level',
                help='less output (warning level)')
            self.add_argument(
                '-v', '--verbose',
                action='count', dest='verbosity_level', default=0,
                help='more output (repeat up to 3 times for even more)')
            self.add_argument(
                '--save-debug-log',
                action='store_true', dest='save_debug_log',
                help='save debug log to "./mopidy.log"')
            self.add_argument(
                '--config',
                action='store', dest='config_files', type=config_files_type,
                default=DEFAULT_CONFIG, metavar='FILES',
                help='config files to use, colon seperated, later files override')
            self.add_argument(
                '-o', '--option',
                action='append', dest='config_overrides',
                type=config_override_type, metavar='OPTIONS',
                help='`section/key=value` values to override config options')

        def run(self, args, config):
            def on_sigterm(loop):
                logger.info('GLib mainloop got SIGTERM. Exiting...')
                loop.quit()

            loop = GLib.MainLoop()
            GLib.unix_signal_add(
                GLib.PRIORITY_DEFAULT, signal.SIGTERM, on_sigterm, loop)

            mixer_class = self.get_mixer_class(config, args.registry['mixer'])
            backend_classes = args.registry['backend']
            frontend_classes = args.registry['frontend']
            core = None

            exit_status_code = 0
            try:
                mixer = None
                if mixer_class is not None:
                    mixer = self.start_mixer(config, mixer_class)
                if mixer:
                    self.configure_mixer(config, mixer)
                audio = self.start_audio(config, mixer)
                backends = self.start_backends(config, backend_classes, audio)
                core = self.start_core(config, mixer, backends, audio)
                self.start_frontends(config, frontend_classes, core)
                logger.info('Starting GLib mainloop')
                loop.run()
            except (exceptions.BackendError,
                    exceptions.FrontendError,
                    exceptions.MixerError):
                logger.info('Initialization error. Exiting...')
                exit_status_code = 1
            except KeyboardInterrupt:
                logger.info('Interrupted. Exiting...')
            except Exception:
                logger.exception('Uncaught exception')
            finally:
                loop.quit()
                self.stop_frontends(frontend_classes)
                self.stop_core(core)
                self.stop_backends(backend_classes)
                self.stop_audio()
                if mixer_class is not None:
                    self.stop_mixer(mixer_class)
                process.stop_remaining_actors()
                return exit_status_code

        def get_mixer_class(self, config, mixer_classes):
            logger.debug(
                'Available Mopidy mixers: %s',
                ', '.join(m.__name__ for m in mixer_classes) or 'none')

            if config['audio']['mixer'] == 'none':
                logger.debug('Mixer disabled')
                return None

            selected_mixers = [
                m for m in mixer_classes if m.name == config['audio']['mixer']]
            if len(selected_mixers) != 1:
                logger.error(
                    'Did not find unique mixer "%s". Alternatives are: %s',
                    config['audio']['mixer'],
                    ', '.join([m.name for m in mixer_classes]) + ', none' or
                    'none')
                process.exit_process()
            return selected_mixers[0]

        def start_mixer(self, config, mixer_class):
            logger.info('Starting Mopidy mixer: %s', mixer_class.__name__)
            with _actor_error_handling(mixer_class.__name__):
                mixer = mixer_class.start(config=config).proxy()
                try:
                    mixer.ping().get()
                    return mixer
                except pykka.ActorDeadError as exc:
                    logger.error('Actor died: %s', exc)
            return None

        def configure_mixer(self, config, mixer):
            volume = config['audio']['mixer_volume']
            if volume is not None:
                mixer.set_volume(volume)
                logger.info('Mixer volume set to %d', volume)
            else:
                logger.debug('Mixer volume left unchanged')

        def start_audio(self, config, mixer):
            logger.info('Starting Mopidy audio')
            return Audio.start(config=config, mixer=mixer).proxy()

        def start_backends(self, config, backend_classes, audio):
            logger.info(
                'Starting Mopidy backends: %s',
                ', '.join(b.__name__ for b in backend_classes) or 'none')

            backends = []
            for backend_class in backend_classes:
                with _actor_error_handling(backend_class.__name__):
                    with timer.time_logger(backend_class.__name__):
                        backend = backend_class.start(
                            config=config, audio=audio).proxy()
                        backends.append(backend)

            # Block until all on_starts have finished, letting them run in parallel
            for backend in backends[:]:
                try:
                    backend.ping().get()
                except pykka.ActorDeadError as exc:
                    backends.remove(backend)
                    logger.error('Actor died: %s', exc)

            return backends

        def start_core(self, config, mixer, backends, audio):
            logger.info('Starting Mopidy core')
            core = Core.start(
                config=config, mixer=mixer, backends=backends, audio=audio).proxy()
            core.setup().get()
            return core

        def start_frontends(self, config, frontend_classes, core):
            logger.info(
                'Starting Mopidy frontends: %s',
                ', '.join(f.__name__ for f in frontend_classes) or 'none')

            for frontend_class in frontend_classes:
                with _actor_error_handling(frontend_class.__name__):
                    with timer.time_logger(frontend_class.__name__):
                        frontend_class.start(config=config, core=core)

        def stop_frontends(self, frontend_classes):
            logger.info('Stopping Mopidy frontends')
            for frontend_class in frontend_classes:
                process.stop_actors_by_class(frontend_class)

        def stop_core(self, core):
            logger.info('Stopping Mopidy core')
            if core:
                core.teardown().get()
            process.stop_actors_by_class(Core)

        def stop_backends(self, backend_classes):
            logger.info('Stopping Mopidy backends')
            for backend_class in backend_classes:
                process.stop_actors_by_class(backend_class)

        def stop_audio(self):
            logger.info('Stopping Mopidy audio')
            process.stop_actors_by_class(Audio)

        def stop_mixer(self, mixer_class):
            logger.info('Stopping Mopidy mixer')
            process.stop_actors_by_class(mixer_class)

    class ConfigCommand(Command):
        help = 'Show currently active configuration.'

        def __init__(self):
            super(ConfigCommand, self).__init__()
            self.set(base_verbosity_level=-1)

        def run(self, config, errors, schemas):
            print(config_lib.format(config, schemas, errors))
            return 0

    class DepsCommand(Command):
        help = 'Show dependencies and debug information.'

        def __init__(self):
            super(DepsCommand, self).__init__()
            self.set(base_verbosity_level=-1)

        def run(self):
            print(deps.format_dependency_list())
            return 0