const MQTT = require('./mqtt');
const Zigbee = require('./zigbee');
const logger = require('./util/logger');
const settings = require('./util/settings');
const deviceMapping = require('./devices');
const zigbee2mqtt = require('./converters/zigbee2mqtt');
const mqtt2zigbee = require('./converters/mqtt2zigbee');
const homeassistant = require('./homeassistant');
const debug = require('debug')('zigbee2mqtt')

const mqttConfigRegex = new RegExp(`${settings.get().mqtt.base_topic}/bridge/config/\\w+`, 'g');
const mqttDeviceRegex = new RegExp(`${settings.get().mqtt.base_topic}/\\w+/set`, 'g');
const mqttDevicePrefixRegex = new RegExp(`${settings.get().mqtt.base_topic}/\\w+/\\w+/set`, 'g');

class Controller {

    constructor() {
        this.zigbee = new Zigbee();
        this.mqtt = new MQTT();
        this.stateCache = {};
        this.handleZigbeeMessage = this.handleZigbeeMessage.bind(this);
        this.handleMQTTMessage = this.handleMQTTMessage.bind(this);
    }

    start() {
        this.zigbee.start(this.handleZigbeeMessage, (error) => {
            if (error) {
                logger.error('Failed to start');
            } else {
                const subscriptions = [
                    `${settings.get().mqtt.base_topic}/+/set`,
                    `${settings.get().mqtt.base_topic}/+/+/set`,
                    `${settings.get().mqtt.base_topic}/bridge/config/+`
                ];
                this.mqtt.connect(this.handleMQTTMessage, subscriptions, () => this.handleStarted());
            }
        });
    }

    handleStarted() {
        // Home Assistant MQTT discovery on startup.
        if (settings.get().homeassistant) {
            // MQTT discovery of all paired devices on startup.
            this.zigbee.getAllClients().forEach((device) => {
                if (deviceMapping[device.modelId]) {
                    homeassistant.discover(device.ieeeAddr, deviceMapping[device.modelId].homeassistant, this.mqtt);
                }
            });
        }

        // Enable zigbee join.
        if (settings.get().permit_join) {
            logger.warn('`permit_join` set to  `true` in configuration.yaml.')
            logger.warn('Allowing new devices to join.');
            logger.warn('Set `permit_join` to `false` once you joined all devices.');
            this.zigbee.permitJoin(true);
        }
    }

    stop(callback) {
        this.mqtt.disconnect();
        this.zigbee.stop(callback);
    }

    handleZigbeeMessage(message) {
        debug('Recieved zigbee message with data', message.data);

        if (message.type == 'devInterview') {
            logger.info('Connecting with device, please wait...');
        } else if (message.type == 'devIncoming') {
            logger.info('New device joined the network!');
        }

        // We dont handle messages without endpoints.
        if (!message.endpoints) {
            return;
        }

        const device = message.endpoints[0].device;

        if (!device) {
            logger.warn('Message without device!');
            return;
        }

        // Check if this is a new device.
        if (!settings.getDevice(device.ieeeAddr)) {
            logger.info(`New device with address ${device.ieeeAddr} connected!`);
            settings.addDevice(device.ieeeAddr);
        }

        // We can't handle devices without modelId.
        if (!device.modelId) {
            return;
        }

        // Map Zigbee modelID to vendor modelID.
        const modelID = message.endpoints[0].device.modelId;
        const mappedModel = deviceMapping[modelID];

        if (!mappedModel) {
            logger.warn(`Device with modelID '${modelID}' is not supported.`);
            logger.warn('Please create an issue on https://github.com/Koenkk/zigbee2mqtt/issues to add support for your device');
            return;
        }

        // Home Assistant MQTT discovery
        if (settings.get().homeassistant) {
            homeassistant.discover(device.ieeeAddr, mappedModel.homeassistant, this.mqtt);
        }

        // After this point we cant handle message withoud cid anymore.
        if (!message.data.cid) {
            return;
        }

        // Find a conveter for this message.
        const cid = message.data.cid;
        const converters = zigbee2mqtt.filter((c) => c.devices.includes(mappedModel.model) && c.cid === cid && c.type === message.type);

        if (!converters.length) {
            logger.warn(`No converter available for '${mappedModel.model}' with cid '${cid}' and type '${message.type}'`);
            logger.warn('Please create an issue on https://github.com/Koenkk/zigbee2mqtt/issues with this message.');
            return;
        }

        // Convert this Zigbee message to a MQTT message.
        // Get payload for the message.
        // - If a payload is returned publish it to the MQTT broker
        // - If NO payload is returned do nothing. This is for non-standard behaviour
        //   for e.g. click switches where we need to count number of clicks and detect long presses.
        converters.forEach((converter) => {
            const publish = (payload) => this.mqttPublishDeviceState(device.ieeeAddr, payload);
            const payload = converter.convert(message, publish);

            if (payload) {
                this.stateCache[device.ieeeAddr] = {...this.stateCache[device.ieeeAddr], ...payload};

                if (!converter.disablePublish) {
                    publish(payload);
                }
            }
        });
    }

    handleMQTTMessage(topic, message) {
        if (topic.match(mqttConfigRegex)) {
            this.handleMQTTMessageConfig(topic, message);
        } else if (topic.match(mqttDeviceRegex) || topic.match(mqttDevicePrefixRegex)) {
            this.handleMQTTMessageDevice(topic, message, topic.match(mqttDevicePrefixRegex));
        } else {
            logger.warn(`Cannot handle MQTT message with topic '${topic}' and message '${message}'`);
        }
    }

    handleMQTTMessageConfig(topic, message) {
        const option = topic.split('/')[3];

        if (option === 'permit_join') {
            this.zigbee.permitJoin(message.toString().toLowerCase() === 'true');
        } else {
            logger.warn(`Cannot handle MQTT config option '${option}' with message '${message}'`);
        }
    }

    handleMQTTMessageDevice(topic, message, withPrefix) {
        const friendlyName = topic.split('/')[1];
        const topicPrefix = withPrefix ? topic.split('/')[2] : '';

        // Map friendlyName to deviceID.
        const deviceID = Object.keys(settings.get().devices).find((id) => settings.getDevice(id).friendly_name === friendlyName);
        if (!deviceID) {
            logger.error(`Cannot handle '${topic}' because deviceID of '${friendlyName}' cannot be found`);
            return;
        }

        // Convert the MQTT message to a Zigbee message.
        let json = null;
        try {
            json = JSON.parse(message);
        } catch (e) {
            // Cannot be parsed to JSON, assume state message.
            json = {state: message.toString()};
        }

        // Find ep for this device
        const mappedModel = deviceMapping[this.zigbee.getDevice(deviceID).modelId];
        const ep = mappedModel.ep && mappedModel.ep[topicPrefix] ? mappedModel.ep[topicPrefix] : null;

        Object.keys(json).forEach((key) => {
            // Find converter for this key.
            const converter = mqtt2zigbee[key];
            if (!converter) {
                logger.error(`No converter available for '${key}' (${json[key]})`);
                return;
            }

            const message = converter(json[key]);
            const callback = (error) => {
                // Devices do not report when they go off, this ensures state (on/off) is always in sync.
                if (!error && key.startsWith('state')) {
                    const msg = {};
                    msg[key] = json[key];
                    this.mqttPublishDeviceState(deviceID, msg);
                }
            };

            this.zigbee.publish(deviceID, message.cId, message.cmd, message.zclData, ep, callback);
        });
    }

    mqttPublishDeviceState(deviceID, payload) {
        if (this.stateCache[deviceID]) {
            payload = {...this.stateCache[deviceID], ...payload};
        }

        // Update state cache with new state.
        this.stateCache[deviceID] = payload;

        const deviceSettings = settings.getDevice(deviceID);
        this.mqtt.publish(deviceSettings.friendly_name, JSON.stringify(payload), deviceSettings.retain);
    }
}

module.exports = Controller;