"""
Support for ZigBee devices.

For more details about this component, please refer to the documentation at
https://home-assistant.io/components/zigbee/
"""
import logging
import pickle
from binascii import hexlify, unhexlify
from base64 import b64encode, b64decode

import voluptuous as vol

from homeassistant.const import (
    EVENT_HOMEASSISTANT_STOP, CONF_DEVICE, CONF_NAME, CONF_PIN)
from homeassistant.helpers.entity import Entity
from homeassistant.helpers import config_validation as cv

REQUIREMENTS = ['xbee-helper==0.0.7']

_LOGGER = logging.getLogger(__name__)

DOMAIN = 'zigbee'

EVENT_ZIGBEE_FRAME_RECEIVED = 'zigbee_frame_received'

CONF_ADDRESS = 'address'
CONF_BAUD = 'baud'

DEFAULT_DEVICE = '/dev/ttyUSB0'
DEFAULT_BAUD = 9600
DEFAULT_ADC_MAX_VOLTS = 1.2

# Copied from xbee_helper during setup()
GPIO_DIGITAL_OUTPUT_LOW = None
GPIO_DIGITAL_OUTPUT_HIGH = None
ADC_PERCENTAGE = None
DIGITAL_PINS = None
ANALOG_PINS = None
CONVERT_ADC = None
ZIGBEE_EXCEPTION = None
ZIGBEE_TX_FAILURE = None

ATTR_FRAME = 'frame'

DEVICE = None

CONFIG_SCHEMA = vol.Schema({
    DOMAIN: vol.Schema({
        vol.Optional(CONF_BAUD, default=DEFAULT_BAUD): cv.string,
        vol.Optional(CONF_DEVICE, default=DEFAULT_DEVICE): cv.string,
    }),
}, extra=vol.ALLOW_EXTRA)

PLATFORM_SCHEMA = vol.Schema({
    vol.Required(CONF_NAME): cv.string,
    vol.Optional(CONF_PIN): cv.positive_int,
    vol.Optional(CONF_ADDRESS): cv.string,
}, extra=vol.ALLOW_EXTRA)


def setup(hass, config):
    """Setup the connection to the ZigBee device."""
    global DEVICE
    global GPIO_DIGITAL_OUTPUT_LOW
    global GPIO_DIGITAL_OUTPUT_HIGH
    global ADC_PERCENTAGE
    global DIGITAL_PINS
    global ANALOG_PINS
    global CONVERT_ADC
    global ZIGBEE_EXCEPTION
    global ZIGBEE_TX_FAILURE

    import xbee_helper.const as xb_const
    from xbee_helper import ZigBee
    from xbee_helper.device import convert_adc
    from xbee_helper.exceptions import ZigBeeException, ZigBeeTxFailure
    from serial import Serial, SerialException

    GPIO_DIGITAL_OUTPUT_LOW = xb_const.GPIO_DIGITAL_OUTPUT_LOW
    GPIO_DIGITAL_OUTPUT_HIGH = xb_const.GPIO_DIGITAL_OUTPUT_HIGH
    ADC_PERCENTAGE = xb_const.ADC_PERCENTAGE
    DIGITAL_PINS = xb_const.DIGITAL_PINS
    ANALOG_PINS = xb_const.ANALOG_PINS
    CONVERT_ADC = convert_adc
    ZIGBEE_EXCEPTION = ZigBeeException
    ZIGBEE_TX_FAILURE = ZigBeeTxFailure

    usb_device = config[DOMAIN].get(CONF_DEVICE, DEFAULT_DEVICE)
    baud = int(config[DOMAIN].get(CONF_BAUD, DEFAULT_BAUD))
    try:
        ser = Serial(usb_device, baud)
    except SerialException as exc:
        _LOGGER.exception("Unable to open serial port for ZigBee: %s", exc)
        return False
    DEVICE = ZigBee(ser)
    hass.bus.listen_once(EVENT_HOMEASSISTANT_STOP, close_serial_port)

    def _frame_received(frame):
        """Called when a ZigBee frame is received.

        Pickles the frame, then encodes it into base64 since it contains
        non JSON serializable binary.
        """
        hass.bus.fire(
            EVENT_ZIGBEE_FRAME_RECEIVED,
            {ATTR_FRAME: b64encode(pickle.dumps(frame)).decode("ascii")})

    DEVICE.add_frame_rx_handler(_frame_received)

    return True


def close_serial_port(*args):
    """Close the serial port we're using to communicate with the ZigBee."""
    DEVICE.zb.serial.close()


def frame_is_relevant(entity, frame):
    """Test whether the frame is relevant to the entity."""
    if frame.get('source_addr_long') != entity.config.address:
        return False
    if 'samples' not in frame:
        return False
    return True


def subscribe(hass, callback):
    """Subscribe to incoming ZigBee frames."""
    def zigbee_frame_subscriber(event):
        """Decode and unpickle the frame from the event bus, and call back."""
        frame = pickle.loads(b64decode(event.data[ATTR_FRAME]))
        callback(frame)

    hass.bus.listen(EVENT_ZIGBEE_FRAME_RECEIVED, zigbee_frame_subscriber)


class ZigBeeConfig(object):
    """Handle the fetching of configuration from the config file."""

    def __init__(self, config):
        """Initialize the configuration."""
        self._config = config
        self._should_poll = config.get("poll", True)

    @property
    def name(self):
        """The name given to the entity."""
        return self._config["name"]

    @property
    def address(self):
        """The address of the device.

        If an address has been provided, unhexlify it, otherwise return None
        as we're talking to our local ZigBee device.
        """
        address = self._config.get("address")
        if address is not None:
            address = unhexlify(address)
        return address

    @property
    def should_poll(self):
        """No polling needed."""
        return self._should_poll


class ZigBeePinConfig(ZigBeeConfig):
    """Handle the fetching of configuration from the config file."""

    @property
    def pin(self):
        """The GPIO pin number."""
        return self._config["pin"]


class ZigBeeDigitalInConfig(ZigBeePinConfig):
    """A subclass of ZigBeePinConfig."""

    def __init__(self, config):
        """Initialise the ZigBee Digital input config."""
        super(ZigBeeDigitalInConfig, self).__init__(config)
        self._bool2state, self._state2bool = self.boolean_maps

    @property
    def boolean_maps(self):
        """Create mapping dictionaries for potential inversion of booleans.

        Create dicts to map the pin state (true/false) to potentially inverted
        values depending on the on_state config value which should be set to
        "low" or "high".
        """
        if self._config.get("on_state", "").lower() == "low":
            bool2state = {
                True: False,
                False: True
            }
        else:
            bool2state = {
                True: True,
                False: False
            }
        state2bool = {v: k for k, v in bool2state.items()}
        return bool2state, state2bool

    @property
    def bool2state(self):
        """A dictionary mapping the internal value to the ZigBee value.

        For the translation of on/off as being pin high or low.
        """
        return self._bool2state

    @property
    def state2bool(self):
        """A dictionary mapping the ZigBee value to the internal value.

        For the translation of pin high/low as being on or off.
        """
        return self._state2bool


class ZigBeeDigitalOutConfig(ZigBeePinConfig):
    """A subclass of ZigBeePinConfig.

    Set _should_poll to default as False instead of True. The value will
    still be overridden by the presence of a 'poll' config entry.
    """

    def __init__(self, config):
        """Initialize the ZigBee Digital out."""
        super(ZigBeeDigitalOutConfig, self).__init__(config)
        self._bool2state, self._state2bool = self.boolean_maps
        self._should_poll = config.get("poll", False)

    @property
    def boolean_maps(self):
        """Create dicts to map booleans to pin high/low and vice versa.

        Depends on the config item "on_state" which should be set to "low"
        or "high".
        """
        if self._config.get("on_state", "").lower() == "low":
            bool2state = {
                True: GPIO_DIGITAL_OUTPUT_LOW,
                False: GPIO_DIGITAL_OUTPUT_HIGH
            }
        else:
            bool2state = {
                True: GPIO_DIGITAL_OUTPUT_HIGH,
                False: GPIO_DIGITAL_OUTPUT_LOW
            }
        state2bool = {v: k for k, v in bool2state.items()}
        return bool2state, state2bool

    @property
    def bool2state(self):
        """A dictionary mapping booleans to GPIOSetting objects.

        For the translation of on/off as being pin high or low.
        """
        return self._bool2state

    @property
    def state2bool(self):
        """A dictionary mapping GPIOSetting objects to booleans.

        For the translation of pin high/low as being on or off.
        """
        return self._state2bool


class ZigBeeAnalogInConfig(ZigBeePinConfig):
    """Representation of a ZigBee GPIO pin set to analog in."""

    @property
    def max_voltage(self):
        """The voltage at which the ADC will report its highest value."""
        return float(self._config.get("max_volts", DEFAULT_ADC_MAX_VOLTS))


class ZigBeeDigitalIn(Entity):
    """Representation of a GPIO pin configured as a digital input."""

    def __init__(self, hass, config):
        """Initialize the device."""
        self._config = config
        self._state = False

        def handle_frame(frame):
            """Handle an incoming frame.

            Handle an incoming frame and update our status if it contains
            information relating to this device.
            """
            if not frame_is_relevant(self, frame):
                return
            sample = frame['samples'].pop()
            pin_name = DIGITAL_PINS[self._config.pin]
            if pin_name not in sample:
                # Doesn't contain information about our pin
                return
            self._state = self._config.state2bool[sample[pin_name]]
            self.update_ha_state()

        subscribe(hass, handle_frame)

        # Get initial state
        self.schedule_update_ha_state(True)

    @property
    def name(self):
        """Return the name of the input."""
        return self._config.name

    @property
    def config(self):
        """The entity's configuration."""
        return self._config

    @property
    def should_poll(self):
        """Return the state of the polling, if needed."""
        return self._config.should_poll

    @property
    def is_on(self):
        """Return True if the Entity is on, else False."""
        return self._state

    def update(self):
        """Ask the ZigBee device what state its input pin is in."""
        try:
            sample = DEVICE.get_sample(self._config.address)
        except ZIGBEE_TX_FAILURE:
            _LOGGER.warning(
                "Transmission failure when attempting to get sample from "
                "ZigBee device at address: %s", hexlify(self._config.address))
            return
        except ZIGBEE_EXCEPTION as exc:
            _LOGGER.exception(
                "Unable to get sample from ZigBee device: %s", exc)
            return
        pin_name = DIGITAL_PINS[self._config.pin]
        if pin_name not in sample:
            _LOGGER.warning(
                "Pin %s (%s) was not in the sample provided by ZigBee device "
                "%s.",
                self._config.pin, pin_name, hexlify(self._config.address))
            return
        self._state = self._config.state2bool[sample[pin_name]]


class ZigBeeDigitalOut(ZigBeeDigitalIn):
    """Representation of a GPIO pin configured as a digital input."""

    def _set_state(self, state):
        """Initialize the ZigBee digital out device."""
        try:
            DEVICE.set_gpio_pin(
                self._config.pin,
                self._config.bool2state[state],
                self._config.address)
        except ZIGBEE_TX_FAILURE:
            _LOGGER.warning(
                "Transmission failure when attempting to set output pin on "
                "ZigBee device at address: %s", hexlify(self._config.address))
            return
        except ZIGBEE_EXCEPTION as exc:
            _LOGGER.exception(
                "Unable to set digital pin on ZigBee device: %s", exc)
            return
        self._state = state
        if not self.should_poll:
            self.update_ha_state()

    def turn_on(self, **kwargs):
        """Set the digital output to its 'on' state."""
        self._set_state(True)

    def turn_off(self, **kwargs):
        """Set the digital output to its 'off' state."""
        self._set_state(False)

    def update(self):
        """Ask the ZigBee device what its output is set to."""
        try:
            pin_state = DEVICE.get_gpio_pin(
                self._config.pin,
                self._config.address)
        except ZIGBEE_TX_FAILURE:
            _LOGGER.warning(
                "Transmission failure when attempting to get output pin status"
                " from ZigBee device at address: %s",
                hexlify(self._config.address))
            return
        except ZIGBEE_EXCEPTION as exc:
            _LOGGER.exception(
                "Unable to get output pin status from ZigBee device: %s", exc)
            return
        self._state = self._config.state2bool[pin_state]


class ZigBeeAnalogIn(Entity):
    """Representation of a GPIO pin configured as an analog input."""

    def __init__(self, hass, config):
        """Initialize the ZigBee analog in device."""
        self._config = config
        self._value = None

        def handle_frame(frame):
            """Handle an incoming frame.

            Handle an incoming frame and update our status if it contains
            information relating to this device.
            """
            if not frame_is_relevant(self, frame):
                return
            sample = frame['samples'].pop()
            pin_name = ANALOG_PINS[self._config.pin]
            if pin_name not in sample:
                # Doesn't contain information about our pin
                return
            self._value = CONVERT_ADC(
                sample[pin_name],
                ADC_PERCENTAGE,
                self._config.max_voltage
            )
            self.update_ha_state()

        subscribe(hass, handle_frame)

        # Get initial state
        hass.add_job(self.async_update_ha_state, True)

    @property
    def name(self):
        """The name of the input."""
        return self._config.name

    @property
    def config(self):
        """The entity's configuration."""
        return self._config

    @property
    def should_poll(self):
        """The state of the polling, if needed."""
        return self._config.should_poll

    @property
    def state(self):
        """Return the state of the entity."""
        return self._value

    @property
    def unit_of_measurement(self):
        """Return the unit this state is expressed in."""
        return "%"

    def update(self):
        """Get the latest reading from the ADC."""
        try:
            self._value = DEVICE.read_analog_pin(
                self._config.pin,
                self._config.max_voltage,
                self._config.address,
                ADC_PERCENTAGE)
        except ZIGBEE_TX_FAILURE:
            _LOGGER.warning(
                "Transmission failure when attempting to get sample from "
                "ZigBee device at address: %s", hexlify(self._config.address))
        except ZIGBEE_EXCEPTION as exc:
            _LOGGER.exception(
                "Unable to get sample from ZigBee device: %s", exc)
