import "paho-mqtt";
import MQTT = Paho.MQTT;

import {
    Duration,
    ISprinklersApi,
    Program,
    ProgramItem,
    Schedule,
    Section,
    SectionRun,
    SectionRunner,
    SprinklersDevice,
    TimeOfDay,
} from "@common/sprinklers";
import { checkedIndexOf } from "@common/utils";

export class MqttApiClient implements ISprinklersApi {
    client: MQTT.Client;
    connected: boolean;
    devices: { [prefix: string]: MqttSprinklersDevice } = {};

    constructor() {
        this.client = new MQTT.Client(location.hostname, 1884, MqttApiClient.newClientId());
        this.client.onMessageArrived = (m) => this.onMessageArrived(m);
        this.client.onConnectionLost = (e) => this.onConnectionLost(e);
        // (this.client as any).trace = (m => console.log(m));
    }

    private static newClientId() {
        return "sprinklers3-MqttApiClient-" + Math.round(Math.random() * 1000);
    }

    start() {
        console.log("connecting to mqtt with client id %s", this.client.clientId);
        this.client.connect({
            onFailure: (e) => {
                console.log("mqtt error: ", e.errorMessage);
            },
            onSuccess: () => {
                console.log("mqtt connected");
                this.connected = true;
                for (const prefix of Object.keys(this.devices)) {
                    const device = this.devices[prefix];
                    device.doSubscribe();
                }
            },
        });
    }

    getDevice(prefix: string): SprinklersDevice {
        if (/\//.test(prefix)) {
            throw new Error("Prefix cannot contain a /");
        }
        if (!this.devices[prefix]) {
            const device = this.devices[prefix] = new MqttSprinklersDevice(this, prefix);
            if (this.connected) {
                device.doSubscribe();
            }
        }
        return this.devices[prefix];
    }

    removeDevice(prefix: string) {
        const device = this.devices[prefix];
        if (!device) {
            return;
        }
        device.doUnsubscribe();
        delete this.devices[prefix];
    }

    private onMessageArrived(m: MQTT.Message) {
        try {
            this.processMessage(m);
        } catch (e) {
            console.error("error while processing mqtt message", e);
        }
    }

    private processMessage(m: MQTT.Message) {
        // console.log("message arrived: ", m);
        if (m.destinationName == null) {
            console.warn(`revieved invalid message: ${m}`);
            return;
        }
        const topicIdx = m.destinationName.indexOf("/"); // find the first /
        const prefix = m.destinationName.substr(0, topicIdx); // assume prefix does not contain a /
        const topic = m.destinationName.substr(topicIdx + 1);
        const device = this.devices[prefix];
        if (!device) {
            console.warn(`received message for unknown device. prefix: ${prefix}`);
            return;
        }
        device.onMessage(topic, m.payloadString);
    }

    private onConnectionLost(e: MQTT.MQTTError) {
        this.connected = false;
    }
}

const subscriptions =  [
    "/connected",
    "/sections",
    "/sections/+/#",
    "/programs",
    "/programs/+/#",
    "/responses/+",
    "/section_runner",
];

class MqttSprinklersDevice extends SprinklersDevice {
    readonly apiClient: MqttApiClient;
    readonly prefix: string;

    private responseCallbacks: {
        [rid: number]: ResponseCallback;
    } = {};

    constructor(apiClient: MqttApiClient, prefix: string) {
        super();
        this.apiClient = apiClient;
        this.prefix = prefix;
        this.sectionRunner = new MqttSectionRunner(this);
    }

    get id(): string {
        return this.prefix;
    }

    doSubscribe() {
        const c = this.apiClient.client;
        subscriptions
            .forEach((filter) => c.subscribe(this.prefix + filter, { qos: 1 }));
    }

    doUnsubscribe() {
        const c = this.apiClient.client;
        subscriptions
            .forEach((filter) => c.unsubscribe(this.prefix + filter));
    }

    /**
     * Updates this device with the specified message
     * @param topic The topic, with prefix removed
     * @param payload The payload string
     */
    onMessage(topic: string, payload: string) {
        if (topic === "connected") {
            this.connected = (payload === "true");
            // console.log(`MqttSprinklersDevice with prefix ${this.prefix}: ${this.connected}`)
            return;
        }
        let matches = topic.match(/^sections(?:\/(\d+)(?:\/?(.+))?)?$/);
        if (matches != null) {
            //noinspection JSUnusedLocalSymbols
            /* tslint:disable-next-line:no-unused-variable */
            const [_topic, secStr, subTopic] = matches;
            // console.log(`section: ${secStr}, topic: ${subTopic}, payload: ${payload}`);
            if (!secStr) { // new number of sections
                this.sections.length = Number(payload);
            } else {
                const secNum = Number(secStr);
                let section = this.sections[secNum];
                if (!section) {
                    this.sections[secNum] = section = new MqttSection(this);
                }
                (section as MqttSection).onMessage(subTopic, payload);
            }
            return;
        }
        matches = topic.match(/^programs(?:\/(\d+)(?:\/?(.+))?)?$/);
        if (matches != null) {
            //noinspection JSUnusedLocalSymbols
            /* tslint:disable-next-line:no-unused-variable */
            const [_topic, progStr, subTopic] = matches;
            // console.log(`program: ${progStr}, topic: ${subTopic}, payload: ${payload}`);
            if (!progStr) { // new number of programs
                this.programs.length = Number(payload);
            } else {
                const progNum = Number(progStr);
                let program = this.programs[progNum];
                if (!program) {
                    this.programs[progNum] = program = new MqttProgram(this);
                }
                (program as MqttProgram).onMessage(subTopic, payload);
            }
            return;
        }
        matches = topic.match(/^section_runner$/);
        if (matches != null) {
            (this.sectionRunner as MqttSectionRunner).onMessage(payload);
            return;
        }
        matches = topic.match(/^responses\/(\d+)$/);
        if (matches != null) {
            //noinspection JSUnusedLocalSymbols
            /* tslint:disable-next-line:no-unused-variable */
            const [_topic, respIdStr] = matches;
            // console.log(`response: ${respIdStr}`);
            const respId = parseInt(respIdStr, 10);
            const data = JSON.parse(payload) as IResponseData;
            const cb = this.responseCallbacks[respId];
            if (typeof cb === "function") {
                cb(data);
            }
            return;
        }
        console.warn(`MqttSprinklersDevice recieved invalid topic: ${topic}`);
    }

    runSection(section: Section | number, duration: Duration) {
        const sectionNum = checkedIndexOf(section, this.sections, "Section");
        const payload: IRunSectionJSON = {
            duration: duration.toSeconds(),
        };
        return this.makeRequest(`sections/${sectionNum}/run`, payload);
    }

    runProgram(program: Program | number) {
        const programNum = checkedIndexOf(program, this.programs, "Program");
        return this.makeRequest(`programs/${programNum}/run`, {});
    }

    cancelSectionRunById(id: number) {
        return this.makeRequest(`section_runner/cancel_id`, { id });
    }

    pauseSectionRunner() {
        return this.makeRequest(`section_runner/pause`);
    }

    unpauseSectionRunner() {
        return this.makeRequest(`section_runner/unpause`);
    }

    //noinspection JSMethodCanBeStatic
    private nextRequestId(): number {
        return Math.floor(Math.random() * 1000000000);
    }

    private makeRequest(topic: string, payload: object | string = {}): Promise<IResponseData> {
        return new Promise<IResponseData>((resolve, reject) => {
            const payloadStr = (typeof payload === "string") ?
                payload : JSON.stringify(payload);
            const message = new MQTT.Message(payloadStr);
            message.destinationName = this.prefix + "/" + topic;
            const requestId = this.nextRequestId();
            this.responseCallbacks[requestId] = (data) => {
                if (data.error != null) {
                    reject(data);
                } else {
                    resolve(data);
                }
            };
            this.apiClient.client.send(message);
        });

    }
}

interface IResponseData {
    reqTopic: string;
    error?: string;

    [key: string]: any;
}

type ResponseCallback = (data: IResponseData) => void;

interface ISectionJSON {
    name: string;
    pin: number;
}

interface IRunSectionJSON {
    duration: number;
}

class MqttSection extends Section {
    onMessage(topic: string, payload: string) {
        if (topic === "state") {
            this.state = (payload === "true");
        } else if (topic == null) {
            const json = JSON.parse(payload) as ISectionJSON;
            this.name = json.name;
        }
    }
}

interface ITimeOfDayJSON {
    hour: number;
    minute: number;
    second: number;
    millisecond: number;
}

function timeOfDayFromJSON(json: ITimeOfDayJSON): TimeOfDay {
    return new TimeOfDay(json.hour, json.minute, json.second, json.millisecond);
}

interface IScheduleJSON {
    times: ITimeOfDayJSON[];
    weekdays: number[];
    from?: string;
    to?: string;
}

function scheduleFromJSON(json: IScheduleJSON): Schedule {
    const sched = new Schedule();
    sched.times = json.times.map(timeOfDayFromJSON);
    sched.weekdays = json.weekdays;
    sched.from = json.from == null ? null : new Date(json.from);
    sched.to = json.to == null ? null : new Date(json.to);
    return sched;
}

interface IProgramItemJSON {
    section: number;
    duration: number;
}

interface IProgramJSON {
    name: string;
    enabled: boolean;
    sequence: IProgramItemJSON[];
    sched: IScheduleJSON;
}

class MqttProgram extends Program {
    onMessage(topic: string, payload: string) {
        if (topic === "running") {
            this.running = (payload === "true");
        } else if (topic == null) {
            const json = JSON.parse(payload) as Partial<IProgramJSON>;
            this.updateFromJSON(json);
        }
    }

    updateFromJSON(json: Partial<IProgramJSON>) {
        if (json.name != null) {
            this.name = json.name;
        }
        if (json.enabled != null) {
            this.enabled = json.enabled;
        }
        if (json.sequence != null) {
            this.sequence = json.sequence.map((item) => (new ProgramItem(
                item.section,
                Duration.fromSeconds(item.duration),
            )));
        }
        if (json.sched != null) {
            this.schedule = scheduleFromJSON(json.sched);
        }
    }
}

export interface ISectionRunJSON {
    id: number;
    section: number;
    duration: number;
    startTime?: number;
    pauseTime?: number;
}

function sectionRunFromJSON(json: ISectionRunJSON) {
    const run = new SectionRun();
    run.id = json.id;
    run.section = json.section;
    run.duration = Duration.fromSeconds(json.duration);
    run.startTime = json.startTime == null ? null : new Date(json.startTime);
    run.pauseTime = json.pauseTime == null ? null : new Date(json.pauseTime);
    return run;
}

interface ISectionRunnerJSON {
    queue: ISectionRunJSON[];
    current: ISectionRunJSON | null;
    paused: boolean;
}

class MqttSectionRunner extends SectionRunner {
    onMessage(payload: string) {
        const json = JSON.parse(payload) as ISectionRunnerJSON;
        this.updateFromJSON(json);
    }

    updateFromJSON(json: ISectionRunnerJSON) {
        if (!json.queue || !json.queue.length) { // null means empty queue
            this.queue.clear();
        } else {
            this.queue.replace(json.queue.map(sectionRunFromJSON));
        }
        this.current = json.current == null ? null : sectionRunFromJSON(json.current);
    }
}