function addElement(value)
{
	// tworzy nowy element div
	// i daje jego zawartość

	newDiv = document.createElement("div");
	let counter=document.getElementsByTagName('li').length-2;
	newDiv.innerHTML = `<li class="list-group-item"><span class="badge">${counter}</span>${parseFloat(value)}</li>`;

	// add the newly created element and it's content into the DOM
	my_div = document.getElementById("stack");
	my_div.appendChild(newDiv);
}

function enterClicked() {
	// TODO
	//alert("Enter clicked!")

	var value = document.getElementById('input').value;
	var floatValue = parseFloat(value);

	if(value!==""&&floatValue) {
		addElement(value);

		console.log(value);
	}
	document.getElementById('input').value = "";

};

function addClicked() {
	var mydivArray = document.getElementsByTagName("li");
	var my_div = document.getElementById("stack");
	if(mydivArray.length>4) {
		var value1 = parseFloat(my_div.lastElementChild.textContent);
		console.log(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);
		var value2 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);



		var sum = value2 + value1;
		console.log(sum);
		addElement(sum);
	}
	else {
		alert("Za mało elementów na stosie!")
	}

}

function minusClicked(){
	var mydivArray = document.getElementsByTagName("li");
	var my_div = document.getElementById("stack");
	if(mydivArray.length>4){
		var value1 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);
		var value2 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);

		var minus = value2 - value1;
		console.log(minus);
		addElement(minus);
	}
	else {
		alert("Za mało elementów na stosie!")
	}
}

function multiplyClicked(){
	var mydivArray = document.getElementsByTagName("li");
	var my_div = document.getElementById("stack");
	if(mydivArray.length>4) {
		var value1 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);
		var value2 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);

		var sum = value1 * value2;
		console.log(sum);
		addElement(sum);
	}
	else {
		alert("Za mało elementów na stosie!")
	}
}

function divideClicked() {
	var mydivArray = document.getElementsByTagName("li");
	var my_div = document.getElementById("stack");
	if(mydivArray.length>4) {
		var value1 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);
		var value2 = parseFloat(my_div.lastElementChild.textContent);
		my_div.removeChild(my_div.lastElementChild);

		var sum = value2 / value1;
		console.log(sum);
		addElement(sum);
	}
	else {
		alert("Za mało elementów na stosie!")
	}
}