node-gamedig/protocols/openttd.js

const Core = require('./core');

class OpenTtd extends Core {
    async run(state) {
        {
            const [reader, version] = await this.query(0, 1, 1, 4);
            if (version >= 4) {
                const numGrf = reader.uint(1);
                state.raw.grfs = [];
                for (let i = 0; i < numGrf; i++) {
                    const grf = {};
                    grf.id = reader.part(4).toString('hex');
                    grf.md5 = reader.part(16).toString('hex');
                    state.raw.grfs.push(grf);
                }
            }
            if (version >= 3) {
                state.raw.date_current = this.readDate(reader);
                state.raw.date_start = this.readDate(reader);
            }
            if (version >= 2) {
                state.raw.maxcompanies = reader.uint(1);
                state.raw.numcompanies = reader.uint(1);
                state.raw.maxspectators = reader.uint(1);
            }

            state.name = reader.string();
            state.raw.version = reader.string();

            state.raw.language = this.decode(
                reader.uint(1),
                ['any', 'en', 'de', 'fr']
            );

            state.password = !!reader.uint(1);
            state.maxplayers = reader.uint(1);
            state.players.setNum(reader.uint(1));
            state.raw.numspectators = reader.uint(1);
            state.map = reader.string();
            state.raw.map_width = reader.uint(2);
            state.raw.map_height = reader.uint(2);

            state.raw.landscape = this.decode(
                reader.uint(1),
                ['temperate', 'arctic', 'desert', 'toyland']
            );

            state.raw.dedicated = !!reader.uint(1);
        }

        {
            const [reader,version] = await this.query(2,3,-1,-1);
            // we don't know how to deal with companies outside version 6
            if(version === 6) {
                state.raw.companies = [];
                const numCompanies = reader.uint(1);
                for (let iCompany = 0; iCompany < numCompanies; iCompany++) {
                    const company = {};
                    company.id = reader.uint(1);
                    company.name = reader.string();
                    company.year_start = reader.uint(4);
                    company.value = reader.uint(8).toString();
                    company.money = reader.uint(8).toString();
                    company.income = reader.uint(8).toString();
                    company.performance = reader.uint(2);
                    company.password = !!reader.uint(1);

                    const vehicle_types = ['train', 'truck', 'bus', 'aircraft', 'ship'];
                    const station_types = ['station', 'truckbay', 'busstation', 'airport', 'dock'];

                    company.vehicles = {};
                    for (const type of vehicle_types) {
                        company.vehicles[type] = reader.uint(2);
                    }
                    company.stations = {};
                    for (const type of station_types) {
                        company.stations[type] = reader.uint(2);
                    }

                    company.clients = reader.string();
                    state.raw.companies.push(company);
                }
            }
        }
    }

    async query(type,expected,minver,maxver) {
        const b = Buffer.from([0x03,0x00,type]);
        return await this.udpSend(b,(buffer) => {
            const reader = this.reader(buffer);

            const packetLen = reader.uint(2);
            if(packetLen !== buffer.length) {
                this.debugLog('Invalid reported packet length: '+packetLen+' '+buffer.length);
                return;
            }

            const packetType = reader.uint(1);
            if(packetType !== expected) {
                this.debugLog('Unexpected response packet type: '+packetType);
                return;
            }

            const protocolVersion = reader.uint(1);
            if((minver !== -1 && protocolVersion < minver) || (maxver !== -1 && protocolVersion > maxver)) {
                throw new Error('Unknown protocol version: '+protocolVersion+' Expected: '+minver+'-'+maxver);
            }

            return [reader,protocolVersion];
        });
    }

    readDate(reader) {
        const daysSinceZero = reader.uint(4);
        const temp = new Date(0,0,1);
        temp.setFullYear(0);
        temp.setDate(daysSinceZero+1);
        return temp.toISOString().split('T')[0];
    }

    decode(num,arr) {
        if(num < 0 || num >= arr.length) {
            return num;
        }
        return arr[num];
    }
}

module.exports = OpenTtd;