let assert = require('chai').assert

describe('testing a createList func',function(){

    let test=createList()

    beforeEach(function(){
        test=createList()
    })

    it('the list should be empty at the start',function(){


        assert(test.toString(),'', 'bambam')
    })

    it('the list should have all initial functions', function(){

        assert.isFunction(test.add,'add is not a function')
        assert.isFunction(test.shiftLeft,'shiftLeft is not a function')
        assert.isFunction(test.shiftRight,'shiftRight is not a function')
        assert.isFunction(test.swap,'swap is not a function')
        assert.isFunction(test.toString,'to string is not a function')


    })


})

function createList() {
    let data = [];
    return {
        add: function (item) {
            data.push(item)
        },
        shiftLeft: function () {
            if (data.length > 1) {
                let first = data.shift();
                data.push(first);
            }
        },
        shiftRight: function () {
            if (data.length > 1) {
                let last = data.pop();
                data.unshift(last);
            }
        },
        swap: function (index1, index2) {
            if (!Number.isInteger(index1) || index1 < 0 || index1 >= data.length ||
                !Number.isInteger(index2) || index2 < 0 || index2 >= data.length ||
                index1 === index2) {
                return false;
            }
            let temp = data[index1];
            data[index1] = data[index2];
            data[index2] = temp;
            return true;
        },
        toString: function () {
            return data.join(", ");
        }
    };
}