var request; // xml http request object

// Create an XMLHttpRequest object
function create_xml_http_request()
{
	var request = null;
	
	try
	{
		request = new XMLHttpRequest();
	}
	catch( e )
	{
		try
		{
			request = new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch(  e )
		{
			request = new ActiveXObject("Microsoft.XMLHTTP");
		}
	}
	
	return request;
}

function get_xml_node( xml_doc, id, index )
{
	var result = null;
	if( xml_doc.getElementsByTagName( id )[ index ] )
	{
		if( xml_doc.getElementsByTagName( id )[ index ].childNodes.length > 0 ) result = xml_doc.getElementsByTagName( id )[index].childNodes[0].nodeValue;
	}
	return result;
}

/////////////////////////////////////
// ADD
////////////////////////////////////////////////////////////////////////////////

// Updates the product using AJAX
function add( id )
{
	request = create_xml_http_request();
	
	var quantity = document.getElementById( 'icon_quantity_' + id ).value;
	var url = "ajax/basket-add.php"; // creates the XML document
	url = url + "?id=" + id + "&quantity=" + quantity;
	
	request.onreadystatechange=add_state_changed;
	request.open("GET",url,true);
	request.send(null);		
}

// Retrieves the XML data 
function add_state_changed()
{
	if( request.readyState == 4 )
	{
		var xml_doc = request.responseXML.documentElement;
		var id = get_xml_node( xml_doc, "id", 0 ); 
		var product_id = get_xml_node( xml_doc, "product_id", 0 );
		var product_quantity = get_xml_node( xml_doc, "product_quantity", 0 );
		var brand = get_xml_node( xml_doc, "brand", 0 ); 
		var name = get_xml_node( xml_doc, "name", 0 ); 
		var thumb = get_xml_node( xml_doc, "thumb", 0 ); 
		var description = get_xml_node( xml_doc, "description", 0 ); 
		var quantity = get_xml_node( xml_doc, "quantity", 0 );
		var unit_price = get_xml_node( xml_doc, "unit_price", 0 ); 
		var price = get_xml_node( xml_doc, "price", 0 ); 
		var stock = get_xml_node( xml_doc, "stock", 0 );
		var postage_id = get_xml_node( xml_doc, "postage_id", 0 );
		var postage_price = get_xml_node( xml_doc, "postage_price", 0 );
		var postage_description = get_xml_node( xml_doc, "postage_description", 0 );
		
		var objs = document.getElementsByTagName( 'input' );
		
		for( var i = 0; i < objs.length; i++ )
		{
			var obj = objs[ i ];
			if( obj.className == "icon_quantity" )
			{
				obj.value = 1;
			}
		}
		
		add_button( product_id, product_quantity );
		add_basket( id, product_id, brand, name, thumb, description, unit_price, quantity, price, stock, postage_price ); 
		recalculate( 'basket_quantity', 'basket_quantity_' );
		if( document.getElementById( 'timer_' + product_id ) ) hide_div( 'timer_' + product_id );
	}
}

function add_button( id, quantity )
{
	var obj = null;
	if( obj = document.getElementById( 'label_quantity_' + id ) )
	{
		if( quantity == 0 ) 
			document.getElementById( 'icon_' + id ).style.display = "none";

		
		if( obj )
		{
			obj.innerHTML = quantity;
		}
		
		if( quantity != 0 ) 
			document.getElementById( 'icon_' + id ).style.display = "inline";
	}
}

function add_basket( id, product_id, brand, name, thumb, description, unit_price, quantity, price, stock, postage_price )
{
	var obj = document.getElementById( 'basket_' + id );
	// if the variation does not exist then create a new entry
	if( obj == null )
	{
		add_basket_create( id, brand, name, description, quantity, price, stock, postage_price );
		add_checkout_create( id, brand, name, thumb, description, unit_price, quantity, price );
		document.getElementById( 'basket_empty' ).style.display  = "none";
		document.getElementById( 'basket_footer' ).style.display = "block";
	}
	else
	{
		// If the quantity is zero then delete the entry from the list
		if( quantity == null ) remove_item( id );	
		else
		{
			// update the entry value
			document.getElementById ( 'basket_quantity_' + id ).value = quantity;
			document.getElementById ( 'basket_price_' + id ).innerHTML = price;
		}
	}
	
}

function add_basket_create( id, brand, name, description, quantity, price, stock, postage_price )
{	
	var div = document.createElement('div');
	div.setAttribute( 'id', 'basket_' + id );
	div.className = 'item';
	var div_name = document.createElement('div');
	
	div_name.setAttribute( 'class', 'name' );
	var title = "";
	if( brand != '' && brand != null ) title = brand + " ";
	
	title += name;
	if( description != '' && description != null )
		title += ": " + description;
	div_name.innerHTML = title;
	div.appendChild( div_name );
	
	var img_cross = document.createElement( 'span' );
	img_cross.innerHTML = "<a href='' onclick='remove_item(" + id + "); return false;'><img src='images/cross.gif' alt='Remove' title='Remove' style='vertical-align:middle' /></a>";
	
	/*
	var img_cross = document.createElement( 'img' );
	img_cross.setAttribute( 'src', 'images/cross.gif' );
	img_cross.setAttribute( 'alt', 'Remove' );
	img_cross.setAttribute( 'title', 'Remove' );
	img_cross.style.verticalAlign = "bottom";
	
	var href_cross = document.createElement( 'a' );
	href_cross.setAttribute( 'onclick', "remove( " + id + " ); return false;" );
	href_cross.setAttribute( 'href', '#' );
	href_cross.appendChild( img_cross );
	div.appendChild( href_cross );
	*/
	div.appendChild( img_cross );
	
	var input_quantity = document.createElement( 'input' );
	input_quantity.setAttribute( 'type', 'text' );
	input_quantity.setAttribute( 'id', 'basket_quantity_' + id );
	input_quantity.className = "basket_quantity";
	input_quantity.setAttribute( 'name', 'basket_quantity_' + id );
	input_quantity.value = quantity;
	input_quantity.style.marginLeft = "5px";
	input_quantity.style.marginRight = "5px";
	div.appendChild( input_quantity );
	
	var str = document.createElement( 'span' );
	str.innerHTML = " @ ";
	div.appendChild( str );
	
	var span_price = document.createElement( 'span' );
	span_price.setAttribute( 'id', 'basket_price_' + id );
	span_price.innerHTML = price;
	div.appendChild( span_price );
	
	document.getElementById( 'basket_items' ).appendChild( div ); 
}

function add_checkout_create( id, product_id, brand, name, thumb, description, unit_price, quantity, price )
{
	
	// TODO: CREATE THE CHECKOUT ROW HERE
	var table = document.getElementById( 'checkout_table' );
	if( table )
	{
		var tr = table.insertRow( -1 );
		tr.id = 'checkout_' + id;
		tr.setAttribute( 'class', "checkout_row" );
		
		var td = null;
		
		td = tr.insertCell( -1 );
		td.setAttribute( 'width', '15px' );
		td.innerHTML = "<a href='' onclick='remove_item(" + id + "); return false;'><img src='images/cross.gif' alt='Remove' title='Remove' style='vertical-align:middle' /></a>";	
		
		td = tr.insertCell( -1 );
		var url = "product.php?product_id=" + product_id;
		
		var title = "";
		if( brand != '' && brand != null ) title = brand + " ";
		
		title += name;
		if( description != '' && description != null )
			title += ": " + description;
		var str = '<div class="checkout_image">' + 
				  '<div class="thumb" style="float:left; width:100px; margin-right:15px; background-image:url( \'images/' + thumb + '\' );"><a href="' + url + '"><img class="border" src="images/border-image-thumb.png" alt="' + title + '" title="' + title + '" style="width:100px; height:70px" /></a></div></div>' +
				  '<div style="float:left; width:185px"><a href="' + url + '">' + title + '</a></div><div class="clear"><!-- //--></div>';
		td.innerHTML = str;
		
		td = tr.insertCell( -1 );
		td.setAttribute( 'id', 'checkout_uprice_' + id );
		td.innerHTML = unit_price;
		
		td = tr.insertCell( -1 );
		var input = document.createElement( 'input' );
		input.setAttribute( 'id', 'checkout_quantity_' + id );
		input.setAttribute( 'name', 'checkout_quantity_' + id );
		input.className = "checkout_quantity";
		input.value = quantity;
		input.style.width = "50px";
		td.appendChild( input );
		
		td = tr.insertCell( -1 );
		td.setAttribute( 'id', 'checkout_price_' + id );
		td.innerHTML = price;
	}
}

/////////////////////////////////////
// REMOVE
////////////////////////////////////////////////////////////////////////////////

function remove_item( id )
{
	request = create_xml_http_request();
	
	var url = "ajax/basket-remove.php"; // creates the XML document
	url = url + "?id=" + id;
	
	document.getElementById( 'basket_loading' ).style.display = "block";
	
	request.onreadystatechange=remove_state_changed;
	request.open("GET",url,true);
	request.send(null);		
}

function remove_state_changed()
{
	if( request.readyState == 4 )
	{		
		var xml_doc = request.responseXML.documentElement;
		var id = get_xml_node( xml_doc, "id", 0 );
		var product_id = get_xml_node( xml_doc, "product_id", 0 );
		var product_quantity = get_xml_node( xml_doc, "product_quantity", 0 );
		remove_basket( id );
		add_button( product_id, product_quantity );
		recalculate( 'basket_quantity', 'basket_quantity_' );
	}
}

function remove_basket( id )
{
	var obj = document.getElementById( 'basket_' + id );
	var parent_obj = obj.parentNode;
	parent_obj.removeChild( obj );
	
	//alert( 'basket_' + id );
	
	if( obj = document.getElementById( 'checkout_' + id ) )
	{
			//alert( 'checkout_id' + id );
		var parent_obj = obj.parentNode;
		parent_obj.removeChild( obj );
		if( parent_obj.childNodes.length == 2 ) window.location = "checkout.php";
	}
	
	var count = 0;
	for( var i = 0; count == 0 && i < document.getElementsByTagName( 'input' ).length; i++ )
	{
		obj = document.getElementsByTagName( 'input' )[ i ];
		if( obj.className == "basket_quantity" )
			count = 1;
	}
	
	if( count == 0 )
	{
		document.getElementById( 'basket_empty' ).style.display  = "block";
		document.getElementById( 'basket_footer' ).style.display = "none";
		
		// TODO: HIDE THE CHECKOUT TABLE HERE
		if( document.getElementById( 'basket_num_items' ) ) document.getElementById( 'basket_num_items' ).innerHTML = 0;
	}
	
	document.getElementById( 'basket_loading' ).style.display = "none";
}

/////////////////////////////////////
// RECALCULATE
////////////////////////////////////////////////////////////////////////////////

function recalculate( className, prefix )
{
	
	request = create_xml_http_request();
	
	var url = "ajax/basket-recalculate.php"; // creates the XML document
	
	var query_string = null;
	var objs = document.getElementsByTagName( 'input' );
	query_string = "prefix=" + prefix;
	
	for( var i = 0; i < objs.length; i++ )
	{
		var obj = objs[ i ];
		
		if( obj.className == className )
		{
			query_string += "&";
			var str = obj.id + "=" + obj.value;
			query_string += str;
		}
	}
	
	var obj = document.getElementById( 'postage_type' );
	if( obj && obj.options.length != 0 )
		query_string += "&postage_type=" + obj.options[ obj.selectedIndex ].value;

	document.getElementById( 'basket_loading' ).style.display = "block";
	request.onreadystatechange=recalculate_state_changed;
	request.open("POST",url, true);
	request.setRequestHeader( 'Content-type', 'application/x-www-form-urlencoded' );
	//request.setRequestHeader( 'Content-length', query_string.length );
	//request.setRequestHeader( 'Connection', 'close' );
	request.send(query_string);
}

function recalculate_state_changed()
{
	if( request.readyState == 4 )
	{
		var stock_errors = "";
		if( request.responseXML )
		{
			var xml_doc = request.responseXML.documentElement;
			
			var postage_id = get_xml_node( xml_doc, "postage_id", 0 );
			var postage_description = get_xml_node( xml_doc, "postage_description", 0 );
			var postage_price = get_xml_node( xml_doc, "postage_price", 0 );
			
			var country_name = get_xml_node( xml_doc, "country_name", 0 );
			
			var sub_total = get_xml_node( xml_doc, "sub_total", 0 );
			var vat = get_xml_node( xml_doc, "vat", 0 );
			var total = get_xml_node( xml_doc, "total", 0 );
			
			var num_items = 0;
			
			for( var i = 0; i < xml_doc.getElementsByTagName( "variation" ).length; i++ )
			{
				var xml_node = xml_doc.getElementsByTagName( "variation" )[ i ];
				var id = get_xml_node( xml_node, "id", 0 );
				var quantity = get_xml_node( xml_node, "quantity", 0 );
				var stock = get_xml_node( xml_node, "stock", 0 );
				var stock_error = get_xml_node( xml_node, "stock_error", 0 );
				
				if( stock_error == 1 )
				{
					stock_errors += "<p>";
					var brand_name = get_xml_node( xml_node, "brand_name", 0 );
					if( brand_name ) stock_errors += brand_name + " ";
					
					var product_name = get_xml_node( xml_node, "product_name", 0 );
					stock_errors += product_name + " ";
					
					var variation_description = get_xml_node( xml_node, "variation_description", 0 );
					if( variation_description ) stock_errors += ": " + variation_description;
					
					if( quantity > stock  )
					{
						stock_errors += " - Stock available <b>" + stock + "</b>, with <b>" + ( quantity - stock ) + "</b> on order<br />";
					}
					else
					{
						stock_errors += " - Stock available <b>" + quantity + "</b><br />";
					}
					stock_errors += "</p>";
				}
				
				num_items += parseInt(quantity);
				
				var price = get_xml_node( xml_node, "price", 0 );
				var product_id = get_xml_node( xml_node, "product_id", 0 );
				var product_quantity = get_xml_node( xml_node, "product_quantity", 0 );
	
				recalculate_basket( id, quantity, price, postage_price, total );
				recalculate_checkout( id, quantity, price, postage_price, sub_total, vat, total, country_name );
				add_button( product_id, product_quantity );
			}
			
			if( document.getElementById( 'basket_num_items' ) ) document.getElementById( 'basket_num_items' ).innerHTML = num_items;
			
			var opts = document.getElementById( 'postage_type' );
			if( opts )
			{
				opts.options.length = 0;
				
				//TODO: check the above and add the items to the SELECT statement
				// also perform a check to highlight the selected ID
				for( var i = 0; i < xml_doc.getElementsByTagName( "postage_item" ).length; i++ )
				{
					var xml_node = xml_doc.getElementsByTagName( "postage_item" )[ i ];
					var postage_item_id = get_xml_node( xml_node, "postage_item_id", 0 );
					var postage_item_name = get_xml_node( xml_node, "postage_item_name", 0 );
					var postage_item_description = get_xml_node( xml_node, "postage_item_description", 0 );
		
					opts.options[ i ] = new Option( postage_item_name, postage_item_id );
					if( postage_item_id == postage_id )
					{
						opts.selectedIndex = i;
						var obj = document.getElementById( 'postage_description' );	
						if( postage_item_description )
						{
							obj.innerHTML = "* " + postage_item_description;
							obj.style.display = "block";
						}
						else
						{
							obj.innerHTML = "";
							obj.style.display = "none";
						}
					}
		
					
				}
			}
			
			var div_order = null;
			var div_save = null;
			if( ( div_order = document.getElementById( 'div_order' ) ) && ( div_save = document.getElementById( 'div_save' ) ) )
			{
				if( postage_id != null )
				{	
					div_order.style.display = "block";
					div_save.style.display = "none";
				}
				else
				{
					div_order.style.display = "none";
					div_save.style.display = "block";
				}
			}
		}

		document.getElementById( 'basket_loading' ).style.display = "none";
		if( document.getElementById( 'timer_' + product_id ) ) hide_div( 'timer_' + product_id );
		
		if( stock_errors != "" )
		{
			str = "<div style='color:#fef33c'><b>STOCK LEVEL WARNING</b></div><p>Sorry, we don't have enough stock of one or more of the items in your basket to completely fulfil your order.<br /><br /><b>In most cases</b>, your basket will be adjusted to contain the maximum number of available stock and we will dispatch your order as normal.<br /><br />If you have added a <b><font color=#FFFF00>'Special Order'</font></b> item to your basket, it will remain on the order and we will dispatch as soon as the item is back in stock. This will usually be within 28 days, but if dispatch will be delayed any longer than 7 days we'll contact you shortly after your order has been received with an expected delivery date.<br /><br />The item(s) affected can be seen below:</p>" + stock_errors;
			show_message( str );
			// alert( str );
		}
	}
}

function recalculate_basket( id, quantity, price, postage_price, total )
{
	if( obj = document.getElementById( 'basket_quantity_' + id ) ) 
	{
		if( quantity > 0 )
		{
			// quantity greater than zero
			obj.value = quantity;
			if( obj = document.getElementById( 'basket_price_' + id ) )		obj.innerHTML = price;
			if( obj = document.getElementById( 'basket_postage_price' ) )	obj.innerHTML = postage_price;
			if( obj = document.getElementById( 'basket_total' ) )			obj.innerHTML = total;
		}
		else
		{
			// quantity less than or equal to zero
			remove_basket( id );
		}
	}
}

function recalculate_checkout( id, quantity, price, postage_price, sub_total, vat, total, country_name )
{
	// TODO: REASSIGN THE VARIATION VARIABLES -- NOTE< WE ALSO NEED AN IMAGE!!
	if( obj = document.getElementById( 'country_name' ) )				obj.innerHTML = country_name;
	if( obj = document.getElementById( 'checkout_quantity_' + id ) )	obj.value = quantity;	  
	if( obj = document.getElementById( 'checkout_price_' + id ) )		obj.innerHTML = price;
	if( obj = document.getElementById( 'checkout_sub_total' ) )			obj.innerHTML = sub_total;
	if( obj = document.getElementById( 'checkout_sub_total2' ) )		obj.innerHTML = sub_total;
	if( obj = document.getElementById( 'checkout_postage' ) )			obj.innerHTML = postage_price;
	if( obj = document.getElementById( 'checkout_vat' ) )				obj.innerHTML = vat;
	if( obj = document.getElementById( 'checkout_total' ) )				obj.innerHTML = total;
	
	// TODO: - dirty hack! FIX ME AT SOME POINT
	if( obj = document.getElementById( 'postage_message' ) )			
	{
		obj.innerHTML = '';
		if( g_trade != 1 )
		{
			if( country_name == "United Kingdom" )
			{
			obj.innerHTML =  '<p>Need to ship to: <p><b>Channel Islands</b> (JE, GY postcodes) <br /><b>Isle of Man</b> (IM postcodes) <br /><b>Isle of Wight</b> (PO30 & PO34-40 postcodes)<br /><b>Scottish Islands</b> (All HS, All HS, PA34, All ZE postcodes, Orkney, Lewis, Skye & Others) <br />or <b>Northern Ireland</b>? <p>' +
				'<a href="country-select-postage.php?country_id=244&amp;url=checkout.php">Then please click here</a>.</p>' +

			'<br />For <b>Scottish Highlands</b> (All IV, All AB, All KW, All HS, PH22, PH33, PH41 postcodes) <p>' +
				'<a href="country-select-postage.php?country_id=246&amp;url=checkout.php">Please click here</a>.</p>';
			}
		}
		else
		{
			obj.innerHTML =  '<p>We will only ship trade orders to the United Kingdom, if you wish to order trade parts internationally please contact the distributor for your country.</p>';
		}
	}
}