// empty 'total almount' and 'submit button' //
function clear() {
	document.getElementById('submit').innerHTML = '&nbsp';
	document.getElementById('total').innerHTML = '&nbsp';
	
}
function clearall() {
	document.getElementById('itemssubtotal').innerHTML = '&nbsp';
	document.getElementById('lessbulk').innerHTML = '&nbsp';
	document.getElementById('discountcodetext').innerHTML = '&nbsp';
	document.getElementById('postage').innerHTML = '&nbsp';
	clear();
}

// empty 'total' and 'postage' field after edit any information in 'delivery table' //
function reset_address() {	
	document.getElementById('postage').innerHTML = '$ 0';
	document.getElementById('postage_confirm').innerHTML = '<a href="javascript:confirmadd();">Confirm Address</a>';
	document.getElementById('calculate_postage').value = '';
	clear();
}

// empty 'total' and 'discount code %' field after edit in 'Discount Code table' //
function reset_code() {	
	document.getElementById('discountcodetext').innerHTML = '0 %';
	document.getElementById('discountcode_confirm').innerHTML = '<a href="javascript:chk_code();">Confirm discount code</a>';
	document.getElementById('calculate_code').value = '';
	clear();
}

// check the string of 'item qty' //
function chk_qty(str) {
	var value = document.getElementById(str).value;
	var num = Number(document.getElementById(str).value);
	var check = Math.round(document.getElementById(str).value);
	document.getElementById('items_confirm').innerHTML = '<a href="javascript:confirmitems();">Confirm Items</a>';
	clear();
	if ( value != num | value != check | value < 0) {
		alert('"' + value + '" is an INVALID input !');
		var check = 0;
		clear();
	} 	
}

// sum 'price' & 'qty' of all items //
function confirmitems() {

	var total_qty = 0;
	var total_price = 0;
	var total_packing = 0;
	var num = document.getElementById('type_num').value;
	for (i=0;i<num;i++) {
		var name = document.getElementById('type_' + i + '_name').value;
		var qty = document.getElementById('type_' + i + '_qty').value;
		for (j=0;j<qty;j++) {
			var unit_price = Number(document.getElementById(name + '_' + j + '_price').value);
			var unit_packing = Number(document.getElementById(name + '_' + j + '_packing').value);
			var unit_qty = Number(document.getElementById(name + '_' + j + '_qty').value);
			total_qty = Number(total_qty) + (unit_packing * unit_qty);
			total_price = total_price + (unit_price * unit_qty);
		}
	}	
	
	total_price = total_price.toFixed(3);
	
	total_qty = Number(total_qty);
	
	if (total_qty > 0 && total_qty < 500 ) {
		var lessbulk = 0;
	}
	if (total_qty > 499 && total_qty < 1000) { 
		var lessbulk = 5; 
	}
	if (total_qty > 999 && total_qty < 1500) { 
		var lessbulk = 10; 
	}
	if (total_qty > 1500) { 
		var lessbulk = 15; 
	}	
	
	document.getElementById('calculate_items').value = total_price
	document.getElementById('items_confirm').innerHTML = '&nbsp;';
	document.getElementById('itemssubtotal').innerHTML = '$ ' + total_price;
	document.getElementById('calculate_lessbulk').value = total_price * lessbulk/100;
	document.getElementById('lessbulk').innerHTML = lessbulk + '% Off @ total ' + total_qty + 'pcs';
	clear();
}

// copy 'delivery address' from user information' //
function copyadd() {
	document.getElementById('u_street1').value = document.getElementById('user-u_street1').value;
	document.getElementById('u_street2').value = document.getElementById('user-u_street2').value;
	document.getElementById('u_postcode').value = document.getElementById('user-u_postcode').value;
	document.getElementById('u_suburb').value = document.getElementById('user-u_suburb').value;
	document.getElementById('u_state').value = document.getElementById('user-u_state').value;
	document.getElementById('u_country').value = document.getElementById('user-u_country').value;
	document.getElementById('phone').value = document.getElementById('user-phone').value;
	document.getElementById('fax').value = document.getElementById('user-fax').value;
	document.getElementById('postage_confirm').innerHTML = '<a href="javascript:confirmadd();">Confirm Address</a>';
	clear();
}

// check out the postage from 'u_country' //
function confirmadd() {
	var check_add = true;
	var country = document.getElementById('u_country').value;
	var state = document.getElementById('u_state').value;
	var street = document.getElementById('u_street1').value;
	if ( country == '') {
		alert('Invalid Country Input');
		clear();
	} else if ( state == '') {
		alert('Invalid State Input');
		clear();
	} else if ( street == '') {
		alert('Invalid Street1 Input');
		clear();
	}
	var postage = 15.00;
	if (country == 'Australia') { 
		var postage = 9;
	}
	document.getElementById('postage').innerHTML = '$ ' + postage;
	document.getElementById('postage_confirm').innerHTML = '&nbsp;';
	document.getElementById('calculate_postage').value = postage;
}

function checkpostage () {
	var country = document.getElementById('u_country').value;
	var postage = 15.00;
	if (country == 'Australia') { 
		var postage = 9;
	}
	document.getElementById('calculate_postage').value = postage;
}

// find out the 'discount' from "chk_code.php" //
function chk_code() {
	var code = document.getElementById('discountcode').value;
	if ( code.length > 0 ) {
		var xmlhttp=null;
		if (window.XMLHttpRequest) {
			// code for IE7+, Firefox, Chrome, Opera, Safari
			xmlhttp=new XMLHttpRequest();
			} else {
			// code for IE6, IE5
			xmlhttp=new ActiveXObject('Microsoft.XMLHTTP');
			}
		var url = 'chk_code.php?code=' + code;
		xmlhttp.open('GET',url,false);
		xmlhttp.send(null);
		var discount = xmlhttp.responseText;
	} else {
		var discount = 0;
	}
	document.getElementById('discountcodetext').innerHTML = discount + ' % Off';
	document.getElementById('discountcode_confirm').innerHTML = '&nbsp;';
	document.getElementById('calculate_code').value = discount;
	clear();
}

// calculate the 'total amount' //
function calculation()
{	
	chk_code();
	confirmitems();			
	checkpostage();
	
	var items = Number(document.getElementById('calculate_items').value);
	var lessbulk = Number(document.getElementById('calculate_lessbulk').value);
	var code = document.getElementById('calculate_code').value;
	var postage= Number(document.getElementById('calculate_postage').value);
	
	var total = 0;
	var total = (( items - lessbulk ) * (1-(code/100)) + postage);

	
	document.getElementById('total').innerHTML = '$ ' + total.toFixed(3);
	document.getElementById('submit').innerHTML = '<input type="submit" value="Confirm Order" />';
	document.getElementById('calculate_total').value = total.toFixed(3);

	if (items < 1) {
		alert('INVALID item qty !');
		clearall();
	} 	
	confirmadd();
	
}