"""Camera that loads a picture from an MQTT topic."""
import functools

import voluptuous as vol

from homeassistant.components import camera
from homeassistant.components.camera import Camera
from homeassistant.const import CONF_NAME
from homeassistant.core import HomeAssistant, callback
from homeassistant.helpers import config_validation as cv
from homeassistant.helpers.reload import async_setup_reload_service
from homeassistant.helpers.typing import ConfigType

from . import CONF_QOS, DOMAIN, PLATFORMS, subscription
from .. import mqtt
from .debug_info import log_messages
from .mixins import MQTT_ENTITY_COMMON_SCHEMA, MqttEntity, async_setup_entry_helper

CONF_TOPIC = "topic"
DEFAULT_NAME = "MQTT Camera"

PLATFORM_SCHEMA = mqtt.MQTT_BASE_PLATFORM_SCHEMA.extend(
    {
        vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
        vol.Required(CONF_TOPIC): mqtt.valid_subscribe_topic,
    }
).extend(MQTT_ENTITY_COMMON_SCHEMA.schema)


async def async_setup_platform(
    hass: HomeAssistant, config: ConfigType, async_add_entities, discovery_info=None
):
    """Set up MQTT camera through configuration.yaml."""
    await async_setup_reload_service(hass, DOMAIN, PLATFORMS)
    await _async_setup_entity(async_add_entities, config)


async def async_setup_entry(hass, config_entry, async_add_entities):
    """Set up MQTT camera dynamically through MQTT discovery."""
    setup = functools.partial(
        _async_setup_entity, async_add_entities, config_entry=config_entry
    )
    await async_setup_entry_helper(hass, camera.DOMAIN, setup, PLATFORM_SCHEMA)


async def _async_setup_entity(
    async_add_entities, config, config_entry=None, discovery_data=None
):
    """Set up the MQTT Camera."""
    async_add_entities([MqttCamera(config, config_entry, discovery_data)])


class MqttCamera(MqttEntity, Camera):
    """representation of a MQTT camera."""

    def __init__(self, config, config_entry, discovery_data):
        """Initialize the MQTT Camera."""
        self._last_image = None

        Camera.__init__(self)
        MqttEntity.__init__(self, None, config, config_entry, discovery_data)

    @staticmethod
    def config_schema():
        """Return the config schema."""
        return PLATFORM_SCHEMA

    async def _subscribe_topics(self):
        """(Re)Subscribe to topics."""

        @callback
        @log_messages(self.hass, self.entity_id)
        def message_received(msg):
            """Handle new MQTT messages."""
            self._last_image = msg.payload

        self._sub_state = await subscription.async_subscribe_topics(
            self.hass,
            self._sub_state,
            {
                "state_topic": {
                    "topic": self._config[CONF_TOPIC],
                    "msg_callback": message_received,
                    "qos": self._config[CONF_QOS],
                    "encoding": None,
                }
            },
        )

    async def async_camera_image(self):
        """Return image response."""
        return self._last_image