MHDMap/server/MhdMapApp.js

import BratislavaOpendata from "./BratislavaOpendata.js";
import config from "../config.js";
import {bearing, removeMilis} from "./math.js";
import ImhdClient from "./ImhdClient.js";
import Recorder from "./Recorder.js";
import getDatabase from "./getDatabase.js";

export default class MhdMapApp {

    constructor(websockets) {
        this.opendata = new BratislavaOpendata(config.openDataKey);
        this.websockets = websockets;

        this.stops = null;
        this.oldVehicles = null;
        this.vehicles = null;
        this.lastUpdatedStatic = null;
        this.lastUpdatedDynamic = null;
        this.lastDelta = null;

        this.imhd = new ImhdClient();
        this.recorder = new Recorder(getDatabase());
    }

    async start() {
        await this.recorder.start();

        this.websockets.on('join', ws => {
            this.sendAction(ws, 'updateStops', this.stops);
            this.sendAction(ws, 'updateVehicles', this.vehicles);
        });
        this.websockets.on('message', this._onWsMessage.bind(this));

        setInterval(() => {
            this.updateStatic();
        }, 1000 * 60 * 60 * 24);

        await this.updateStatic();
        await this.updateDynamic();

        setInterval(async () => {
            await this.updateDynamic();
            if (this.lastDelta.length > 0) {
                this.broadcastAction('updateVehicles', this.lastDelta);
            }
        }, 1000 * 5);

    }

    async updateStatic() {
        let tmp = await this.opendata.fetchAllStops();
        if (tmp) {
            this.stops = tmp;
            this.lastUpdatedStatic = new Date();
        }
    }

    async updateDynamic() {
        let tmp = await this.opendata.fetchAllVehicles();
        if (!tmp)
            return;

        // TODO: We're in Slovakia.
        tmp = tmp.filter(el => el.gpsLongitude > 10);
        tmp = this._vehiclesToObj(tmp);

        this.oldVehicles = this.vehicles;
        this.vehicles = tmp;
        this.lastUpdatedDynamic = new Date();
        if (this.oldVehicles) {
            this.lastDelta = this.calculateVehiclesDelta(this.oldVehicles, this.vehicles);
            this.vehicles = this.addRotationToVehicles(this.oldVehicles, this.vehicles);

            for (let veh of Object.values(this.lastDelta)) {
                await this.recorder.putVehicle(veh);
            }
        } else {
            for (let veh of Object.values(this.vehicles)) {
                await this.recorder.putVehicle(veh);
            }
        }

        this.vehicles = this.addImhdDataToVehicles(this.vehicles);

        let down = 0;
        for (let vehId in this.vehicles) {
            if (await this.imhd.downloadVehicleIcon(vehId) === true) {
                if (down++ === 100) {
                    break;
                }
            }
        }
    }

    calculateVehiclesDelta(beforeObj, afterObj) {
        let delta = {};

        for (let vehId in beforeObj) {
            let beforeVeh = beforeObj[vehId];
            if (afterObj.hasOwnProperty(vehId)) {
                let afterVeh = afterObj[vehId];
                if (!this.isVehicleObjectEqual(beforeVeh, afterVeh)) {
                    delta[vehId] = afterVeh;
                }
            } else {
                // removed vehicle
                beforeVeh.gpsLatitude = -1000;
                beforeVeh.gpsLongitude = -1000;
                delta[vehId] = beforeVeh;
                console.log('vehicle left', beforeVeh);
            }
        }

        for (let vehId in afterObj) {
            if (!beforeObj.hasOwnProperty(vehId)) {
                // new vehicle
                delta[vehId] = afterObj[vehId];
                // console.log('new vehicle joined', afterObj[vehId]);
            }
        }

        return delta;
    }

    _vehiclesToObj(arr) {
        let obj = {};

        for (let vehicle of arr) {
            let id = this._vehicleToId(vehicle);
            vehicle.lastModified = removeMilis(new Date(vehicle.lastModified));

            if (obj.hasOwnProperty(id)) {
                console.log('DUPLICATE vehicle?!', 'old:', obj[id], 'new:', vehicle);
            }
            obj[id] = vehicle;
        }

        return obj;
    }

    _vehicleToId(vehicle) {
        return vehicle.vehicleNumber;
    }

    isVehicleObjectEqual(a, b, checkLastModified = false) {
        return (
            a.vehicleNumber === b.vehicleNumber
            && a.lineNumber === b.lineNumber
            && a.gpsLatitude === b.gpsLatitude
            && a.gpsLongitude === b.gpsLongitude
            && (!checkLastModified || (a.lastModified === b.lastModified))
        );
    }

    isVehiclePositionEqual(a, b) {
        return a.gpsLatitude === b.gpsLatitude && a.gpsLongitude === b.gpsLongitude;
    }

    addImhdDataToVehicles(vehicles) {
        for (let vehId in vehicles) {
            const data = this.imhd.getVehicleData(vehId);
            if (!data)
                continue;

            let vehicle = vehicles[vehId];
            vehicle.img = data.img;
            vehicle.type = data.type;
            vehicle.imhdinfo = data.info;
        }
        return vehicles;
    }

    addRotationToVehicles(before, after) {
        for (let vehId in after) {
            if (before.hasOwnProperty(vehId)) {
                after[vehId].bearing = bearing(before[vehId], after[vehId]);
            }
        }
        return after;
    }

    broadcastAction(action, data) {
        this.websockets.broadcast(JSON.stringify({ action, data }));
    }

    sendAction(ws, action, data) {
        ws.send(JSON.stringify({ action, data }));
    }

    async _onWsMessage(ws, data) {
        // Note: before sending the response, it should be checked if this ws is still open
        try {
            data = JSON.parse(data);
        } catch (e) {
            console.log('Malformed request: ', data, e);
            return null;
        }

        const msgid = data.id;

        let res = await this.handleWsRequest(ws, data.action, data.msg);

        if (ws.readyState !== 1) { // 1 = WebSocket.OPEN
            // closed while handling the request
            return;
        }

        this.sendAction(ws, 'response', {
            id: msgid,
            msg: res,
        });
    }

    async handleWsRequest(ws, action, data) {
        if (action === 'requestVehicleTrace') {
            return await this.recorder.getVehicleTrace(data.vehicle, data.count || 20);
        } else if (action === 'requestLineTrace') {
            return await this.recorder.getSimpleLineTrace(data.line, data.count || 20);
        }
        return null;
    }

}