"""Support for MQTT discovery."""
import asyncio
import json
import logging
import re

from homeassistant.components import mqtt
from homeassistant.const import CONF_DEVICE, CONF_PLATFORM
from homeassistant.helpers.dispatcher import async_dispatcher_send
from homeassistant.helpers.typing import HomeAssistantType

from .abbreviations import ABBREVIATIONS, DEVICE_ABBREVIATIONS
from .const import ATTR_DISCOVERY_HASH, ATTR_DISCOVERY_PAYLOAD, ATTR_DISCOVERY_TOPIC

_LOGGER = logging.getLogger(__name__)

TOPIC_MATCHER = re.compile(
    r"(?P<component>\w+)/(?:(?P<node_id>[a-zA-Z0-9_-]+)/)"
    r"?(?P<object_id>[a-zA-Z0-9_-]+)/config"
)

SUPPORTED_COMPONENTS = [
    "alarm_control_panel",
    "binary_sensor",
    "camera",
    "climate",
    "cover",
    "device_automation",
    "fan",
    "light",
    "lock",
    "sensor",
    "switch",
    "vacuum",
]

ALREADY_DISCOVERED = "mqtt_discovered_components"
CONFIG_ENTRY_IS_SETUP = "mqtt_config_entry_is_setup"
DATA_CONFIG_ENTRY_LOCK = "mqtt_config_entry_lock"
DISCOVERY_UNSUBSCRIBE = "mqtt_discovery_unsubscribe"
MQTT_DISCOVERY_UPDATED = "mqtt_discovery_updated_{}"
MQTT_DISCOVERY_NEW = "mqtt_discovery_new_{}_{}"

TOPIC_BASE = "~"


def clear_discovery_hash(hass, discovery_hash):
    """Clear entry in ALREADY_DISCOVERED list."""
    del hass.data[ALREADY_DISCOVERED][discovery_hash]


def set_discovery_hash(hass, discovery_hash):
    """Clear entry in ALREADY_DISCOVERED list."""
    hass.data[ALREADY_DISCOVERED][discovery_hash] = {}


class MQTTConfig(dict):
    """Dummy class to allow adding attributes."""


async def async_start(
    hass: HomeAssistantType, discovery_topic, config_entry=None
) -> bool:
    """Start MQTT Discovery."""

    async def async_device_message_received(msg):
        """Process the received message."""
        payload = msg.payload
        topic = msg.topic
        topic_trimmed = topic.replace(f"{discovery_topic}/", "", 1)
        match = TOPIC_MATCHER.match(topic_trimmed)

        if not match:
            return

        component, node_id, object_id = match.groups()

        if component not in SUPPORTED_COMPONENTS:
            _LOGGER.warning("Integration %s is not supported", component)
            return

        if payload:
            try:
                payload = json.loads(payload)
            except ValueError:
                _LOGGER.warning("Unable to parse JSON %s: '%s'", object_id, payload)
                return

        payload = MQTTConfig(payload)

        for key in list(payload.keys()):
            abbreviated_key = key
            key = ABBREVIATIONS.get(key, key)
            payload[key] = payload.pop(abbreviated_key)

        if CONF_DEVICE in payload:
            device = payload[CONF_DEVICE]
            for key in list(device.keys()):
                abbreviated_key = key
                key = DEVICE_ABBREVIATIONS.get(key, key)
                device[key] = device.pop(abbreviated_key)

        if TOPIC_BASE in payload:
            base = payload.pop(TOPIC_BASE)
            for key, value in payload.items():
                if isinstance(value, str) and value:
                    if value[0] == TOPIC_BASE and key.endswith("topic"):
                        payload[key] = f"{base}{value[1:]}"
                    if value[-1] == TOPIC_BASE and key.endswith("topic"):
                        payload[key] = f"{value[:-1]}{base}"

        # If present, the node_id will be included in the discovered object id
        discovery_id = " ".join((node_id, object_id)) if node_id else object_id
        discovery_hash = (component, discovery_id)

        if payload:
            # Attach MQTT topic to the payload, used for debug prints
            setattr(payload, "__configuration_source__", f"MQTT (topic: '{topic}')")
            discovery_data = {
                ATTR_DISCOVERY_HASH: discovery_hash,
                ATTR_DISCOVERY_PAYLOAD: payload,
                ATTR_DISCOVERY_TOPIC: topic,
            }
            setattr(payload, "discovery_data", discovery_data)

            payload[CONF_PLATFORM] = "mqtt"

        if ALREADY_DISCOVERED not in hass.data:
            hass.data[ALREADY_DISCOVERED] = {}
        if discovery_hash in hass.data[ALREADY_DISCOVERED]:
            # Dispatch update
            _LOGGER.info(
                "Component has already been discovered: %s %s, sending update",
                component,
                discovery_id,
            )
            async_dispatcher_send(
                hass, MQTT_DISCOVERY_UPDATED.format(discovery_hash), payload
            )
        elif payload:
            # Add component
            _LOGGER.info("Found new component: %s %s", component, discovery_id)
            hass.data[ALREADY_DISCOVERED][discovery_hash] = None

            config_entries_key = f"{component}.mqtt"
            async with hass.data[DATA_CONFIG_ENTRY_LOCK]:
                if config_entries_key not in hass.data[CONFIG_ENTRY_IS_SETUP]:
                    if component == "device_automation":
                        # Local import to avoid circular dependencies
                        # pylint: disable=import-outside-toplevel
                        from . import device_automation

                        await device_automation.async_setup_entry(hass, config_entry)
                    else:
                        await hass.config_entries.async_forward_entry_setup(
                            config_entry, component
                        )
                    hass.data[CONFIG_ENTRY_IS_SETUP].add(config_entries_key)

            async_dispatcher_send(
                hass, MQTT_DISCOVERY_NEW.format(component, "mqtt"), payload
            )

    hass.data[DATA_CONFIG_ENTRY_LOCK] = asyncio.Lock()
    hass.data[CONFIG_ENTRY_IS_SETUP] = set()

    hass.data[DISCOVERY_UNSUBSCRIBE] = await mqtt.async_subscribe(
        hass, f"{discovery_topic}/#", async_device_message_received, 0
    )

    return True


async def async_stop(hass: HomeAssistantType) -> bool:
    """Stop MQTT Discovery."""
    if DISCOVERY_UNSUBSCRIBE in hass.data and hass.data[DISCOVERY_UNSUBSCRIBE]:
        hass.data[DISCOVERY_UNSUBSCRIBE]()
        hass.data[DISCOVERY_UNSUBSCRIBE] = None