# Copyright 2015 Cloudbase Solutions Srl
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

from eventlet import patcher
from nova.console import serial as serial_console
from nova.console import type as ctype
from nova import exception
from nova.i18n import _, _LI  # noqa
from oslo_config import cfg
from oslo_log import log as logging
import six

from hyperv.nova import constants
from hyperv.nova import ioutils
from hyperv.nova import namedpipe
from hyperv.nova import serialproxy
from hyperv.nova import utilsfactory
from hyperv.nova import vmutils

CONF = cfg.CONF
LOG = logging.getLogger(__name__)

threading = patcher.original('threading')


class SerialConsoleHandler(object):
    """Handles serial console ops related to a given instance."""
    def __init__(self, instance_name):
        self._vmutils = utilsfactory.get_vmutils()
        self._pathutils = utilsfactory.get_pathutils()

        self._instance_name = instance_name
        self._log_path = self._pathutils.get_vm_console_log_paths(
            self._instance_name)[0]

        self._client_connected = None
        self._input_queue = None
        self._output_queue = None

        self._serial_proxy = None
        self._workers = []

    def start(self):
        self._setup_handlers()

        for worker in self._workers:
            worker.start()

    def stop(self):
        for worker in self._workers:
            worker.stop()

        if self._serial_proxy:
            serial_console.release_port(self._listen_host,
                                        self._listen_port)

    def _setup_handlers(self):
        if CONF.serial_console.enabled:
            self._setup_serial_proxy_handler()

        self._setup_named_pipe_handlers()

    def _setup_serial_proxy_handler(self):
        self._listen_host = (
            CONF.serial_console.proxyclient_address)
        self._listen_port = serial_console.acquire_port(
            self._listen_host)

        LOG.info(_LI('Initializing serial proxy on '
                     '%(addr)s:%(port)s, handling connections '
                     'to instance %(instance_name)s.'),
                     {'addr': self._listen_host,
                      'port': self._listen_port,
                      'instance_name': self._instance_name})

        # Use this event in order to manage
        # pending queue operations.
        self._client_connected = threading.Event()
        self._input_queue = ioutils.IOQueue(
            client_connected=self._client_connected)
        self._output_queue = ioutils.IOQueue(
            client_connected=self._client_connected)

        self._serial_proxy = serialproxy.SerialProxy(
            self._instance_name, self._listen_host,
            self._listen_port, self._input_queue,
            self._output_queue, self._client_connected)

        self._workers.append(self._serial_proxy)

    def _setup_named_pipe_handlers(self):
        # At most 2 named pipes will be used to access the vm serial ports.
        #
        # The named pipe having the 'ro' suffix will be used only for logging
        # while the 'rw' pipe will be used for interactive sessions, logging
        # only when there is no 'ro' pipe.
        serial_port_mapping = self._get_vm_serial_port_mapping()
        log_rw_pipe_output = not serial_port_mapping.get(
            constants.SERIAL_PORT_TYPE_RO)

        for pipe_type, pipe_path in six.iteritems(serial_port_mapping):
            enable_logging = (pipe_type == constants.SERIAL_PORT_TYPE_RO or
                              log_rw_pipe_output)
            handler = self._get_named_pipe_handler(
                pipe_path,
                pipe_type=pipe_type,
                enable_logging=enable_logging)
            self._workers.append(handler)

    def _get_named_pipe_handler(self, pipe_path, pipe_type,
                                enable_logging):
        kwargs = {}
        if pipe_type == constants.SERIAL_PORT_TYPE_RW:
            kwargs = {'input_queue': self._input_queue,
                      'output_queue': self._output_queue,
                      'connect_event': self._client_connected}
        if enable_logging:
            kwargs['log_file'] = self._log_path

        handler = namedpipe.NamedPipeHandler(pipe_path, **kwargs)
        return handler

    def _get_vm_serial_port_mapping(self):
        serial_port_conns = self._vmutils.get_vm_serial_port_connections(
            self._instance_name)

        if not serial_port_conns:
            err_msg = _("No suitable serial port pipe was found "
                        "for instance %(instance_name)s")
            raise vmutils.HyperVException(
                err_msg % {'instance_name': self._instance_name})

        serial_port_mapping = {}
        # At the moment, we tag the pipes by using a pipe path suffix
        # as we can't use the serial port ElementName attribute because of
        # a Hyper-V bug.
        for pipe_path in serial_port_conns:
            port_type = pipe_path[-2:]
            if port_type in [constants.SERIAL_PORT_TYPE_RO,
                             constants.SERIAL_PORT_TYPE_RW]:
                serial_port_mapping[port_type] = pipe_path
            else:
                serial_port_mapping[constants.SERIAL_PORT_TYPE_RW] = pipe_path

        return serial_port_mapping

    def get_serial_console(self):
        if not CONF.serial_console.enabled:
            raise exception.ConsoleTypeUnavailable(console_type='serial')
        return ctype.ConsoleSerial(host=self._listen_host,
                                   port=self._listen_port)