class ButtonClick {
    constructor({ machineId, buttonId, screenId, data }) {
        this.machineId = machineId;
        this.buttonId = buttonId;
        this.screenId = screenId;
        this.data = data;
        this.data = this.data || {};
        this.fieldId = 0xffffffff;
        for (let i = 0; i < 8; i++) {
            if (!(i in this.data)) {
                this.data[i] = '';
            }
            if (typeof this.data[i] !== 'string') {
                this.data[i] = `${this.data[i]}`;
            }
        }
    }

    encode(encoding) {
        const varLenList = (() => {
            const result = [];
            for (let k in this.data) {
                result.push(this.data[k]);
            }
            return result;
        })().map(v => v.length + 1);
        const varsLen = varLenList.reduce((prev, curr) => prev + curr, 0);
        const length = 25 + varsLen;
        const buffer = new Buffer(length);
        const writer = new BufferWriter(buffer, 0, encoding);
        writer.writeUInt32LE(length | messageTypes.button);
        writer.writeUInt32LE(this.machineId);
        writer.writeUInt32LE(this.buttonId);
        writer.writeUInt32LE(this.fieldId);
        writer.writeUInt32LE(this.screenId);
        writer.writeUInt8(0);

        // Your Tom is so smart he counts 2, 3, 4, 1, 5, 6, 7, 8
        const positions = [2, 3, 4, 1, 5, 6, 7, 8];
        for (var i of positions) {
            writer.writeString(this.data[i - 1]);
        }

        for (i = 0; i <= 2; i++) {
            writer.writeUInt8(0);
        }
        return buffer;
    }
}