"""
Receive signals from a keyboard and use it as a remote control.

For more details about this platform, please refer to the documentation at
https://home-assistant.io/components/keyboard_remote/
"""
# pylint: disable=import-error
import threading
import logging
import os
import time

import voluptuous as vol

import homeassistant.helpers.config_validation as cv
from homeassistant.const import (
    EVENT_HOMEASSISTANT_START, EVENT_HOMEASSISTANT_STOP)

REQUIREMENTS = ['evdev==0.6.1']

_LOGGER = logging.getLogger(__name__)

DEVICE_DESCRIPTOR = 'device_descriptor'
DEVICE_ID_GROUP = 'Device description'
DEVICE_NAME = 'device_name'
DOMAIN = 'keyboard_remote'

ICON = 'mdi:remote'

KEY_CODE = 'key_code'
KEY_VALUE = {'key_up': 0, 'key_down': 1, 'key_hold': 2}
KEYBOARD_REMOTE_COMMAND_RECEIVED = 'keyboard_remote_command_received'
KEYBOARD_REMOTE_CONNECTED = 'keyboard_remote_connected'
KEYBOARD_REMOTE_DISCONNECTED = 'keyboard_remote_disconnected'

TYPE = 'type'

CONFIG_SCHEMA = vol.Schema({
    DOMAIN:
        vol.All(cv.ensure_list, [vol.Schema({
            vol.Exclusive(DEVICE_DESCRIPTOR, DEVICE_ID_GROUP): cv.string,
            vol.Exclusive(DEVICE_NAME, DEVICE_ID_GROUP): cv.string,
            vol.Optional(TYPE, default='key_up'):
                vol.All(cv.string, vol.Any('key_up', 'key_down', 'key_hold'))
        })])
}, extra=vol.ALLOW_EXTRA)


def setup(hass, config):
    """Set up the keyboard_remote."""
    config = config.get(DOMAIN)

    keyboard_remote = KeyboardRemote(hass, config)

    def _start_keyboard_remote(_event):
        keyboard_remote.run()

    def _stop_keyboard_remote(_event):
        keyboard_remote.stop()

    hass.bus.listen_once(EVENT_HOMEASSISTANT_START, _start_keyboard_remote)
    hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, _stop_keyboard_remote)

    return True


class KeyboardRemoteThread(threading.Thread):
    """This interfaces with the inputdevice using evdev."""

    def __init__(self, hass, device_name, device_descriptor, key_value):
        """Construct a thread listening for events on one device."""
        self.hass = hass
        self.device_name = device_name
        self.device_descriptor = device_descriptor
        self.key_value = key_value

        if self.device_descriptor:
            self.device_id = self.device_descriptor
        else:
            self.device_id = self.device_name

        self.dev = self._get_keyboard_device()
        if self.dev is not None:
            _LOGGER.debug("Keyboard connected, %s", self.device_id)
        else:
            _LOGGER.debug(
                "Keyboard not connected, %s. "
                "Check /dev/input/event* permissions", self.device_id)

            id_folder = '/dev/input/by-id/'

            if os.path.isdir(id_folder):
                from evdev import InputDevice, list_devices
                device_names = [InputDevice(file_name).name
                                for file_name in list_devices()]
                _LOGGER.debug(
                    "Possible device names are: %s. "
                    "Possible device descriptors are %s: %s",
                    device_names, id_folder, os.listdir(id_folder))

        threading.Thread.__init__(self)
        self.stopped = threading.Event()
        self.hass = hass

    def _get_keyboard_device(self):
        """Get the keyboard device."""
        from evdev import InputDevice, list_devices
        if self.device_name:
            devices = [InputDevice(file_name) for file_name in list_devices()]
            for device in devices:
                if self.device_name == device.name:
                    return device
        elif self.device_descriptor:
            try:
                device = InputDevice(self.device_descriptor)
            except OSError:
                pass
            else:
                return device
        return None

    def run(self):
        """Run the loop of the KeyboardRemote."""
        from evdev import categorize, ecodes

        if self.dev is not None:
            self.dev.grab()
            _LOGGER.debug("Interface started for %s", self.dev)

        while not self.stopped.isSet():
            # Sleeps to ease load on processor
            time.sleep(.05)

            if self.dev is None:
                self.dev = self._get_keyboard_device()
                if self.dev is not None:
                    self.dev.grab()
                    self.hass.bus.fire(KEYBOARD_REMOTE_CONNECTED)
                    _LOGGER.debug("Keyboard re-connected, %s", self.device_id)
                else:
                    continue

            try:
                event = self.dev.read_one()
            except IOError:  # Keyboard Disconnected
                self.dev = None
                self.hass.bus.fire(KEYBOARD_REMOTE_DISCONNECTED)
                _LOGGER.debug("Keyboard disconnected, %s", self.device_id)
                continue

            if not event:
                continue

            if event.type is ecodes.EV_KEY and event.value is self.key_value:
                _LOGGER.debug(categorize(event))
                self.hass.bus.fire(
                    KEYBOARD_REMOTE_COMMAND_RECEIVED,
                    {
                        KEY_CODE: event.code,
                        DEVICE_DESCRIPTOR: self.device_descriptor,
                        DEVICE_NAME: self.device_name
                    }
                )


class KeyboardRemote:
    """Sets up one thread per device."""

    def __init__(self, hass, config):
        """Construct a KeyboardRemote interface object."""
        self.threads = []
        for dev_block in config:
            device_descriptor = dev_block.get(DEVICE_DESCRIPTOR)
            device_name = dev_block.get(DEVICE_NAME)
            key_value = KEY_VALUE.get(dev_block.get(TYPE, 'key_up'))

            if device_descriptor is not None\
                    or device_name is not None:
                thread = KeyboardRemoteThread(
                    hass, device_name, device_descriptor, key_value)
                self.threads.append(thread)

    def run(self):
        """Run all event listener threads."""
        for thread in self.threads:
            thread.start()

    def stop(self):
        """Stop all event listener threads."""
        for thread in self.threads:
            thread.stopped.set()