"use strict";

function BinOperation(operToken, calcFunction, firstOper, secondOper) {
    this.operToken = operToken;
    this.calcFunction = calcFunction;
    this.firstOper = firstOper;
    this.secondOper = secondOper;

    this.toString = () => firstOper.toString() + ' ' + secondOper.toString() + ' ' + this.operToken;
    this.evaluate = (...args) => this.calcFunction(firstOper.evaluate(...args), secondOper.evaluate(...args));
}

function Add(...opers) {
    BinOperation.call(this, '+', (a, b) => a + b, ...opers);
}

function Subtract(...opers) {
    BinOperation.call(this, '-', (a, b) => a - b, ...opers);
}

function Multiply(...opers) {
    BinOperation.call(this, '*', (a, b) => a * b, ...opers);
}

function Divide(...opers) {
    BinOperation.call(this, '/', (a, b) => a / b, ...opers);
}

function Negate(oper) {
    this.oper = oper;

    this.toString = () => oper.toString() + ' negate';
    this.evaluate = (...args) => (-1) * oper.evaluate(...args);
}

function Const(val) {
    this.val = val;

    this.toString = () => val.toString();
    this.evaluate = () => val;
}

function Variable(varName){
    this.varName = varName;

    this.toString = () => varName;
    this.evaluate = (...args) => {
        if (varName === 'x') return args[0];
        if (varName === 'y') return args[1];
        if (varName === 'z') return args[2];
    }
}