// Offsets for canvas framing

var canvasFramePricingOffset8x10 = 60;
var canvasFramePricingOffset11x14 = 60;
var canvasFramePricingOffset16x20 = 90;
var canvasFramePricingOffset20x24 = 120;
var canvasFramePricingOffset24x36 = 150;

var lastPaperType = "";

function updateFramedPriceOptions(form) { 
   var selectOptions = new Array();
   var currSelectionIdx = form.size.selectedIndex;
   var paperSelection = form.on0.options[form.on0.selectedIndex].value;
 
   //alert ("paperSelection = " + paperSelection + " : lastPaperType = " + lastPaperType);
   
   if (paperSelection != lastPaperType) {
      // Copy the original drop-down to an array
      for ( var i = 0; i < form.size.options.length; i++ ) {
         selectOptions.push(form.size.options[i].value);
      }
      
      // Clear out price drop-down
      for (var i = form.size.options.length; i >= 0 ; i--) {
         form.size.options[i] = null;
      }
      
      // Go through each pricing option and modify it with the appropriate offset
      for ( var i = 0; i < selectOptions.length; i++ ) {
         var currItemValue = selectOptions[i];
         var currItemValueArray = currItemValue.split(":");
         var size = currItemValueArray[0];
         var price = currItemValueArray[1];
         var shipping = currItemValueArray[2];
         
         // Compute offset for current size
         var offset = 0;
         if (size == "8x10") {
            offset = canvasFramePricingOffset8x10;
         }
         else if (size == "11x14") {
            offset = canvasFramePricingOffset11x14;
         } 
         else if (size == "16x20") {
            offset = canvasFramePricingOffset16x20;
         } 
         else if (size == "20x24") {
            offset = canvasFramePricingOffset20x24;
         } 
         else if (size == "24x36") {
            offset = canvasFramePricingOffset24x36;
         } 
   
         // Negate offset if we're going from canvas to cotton
         if (paperSelection == "Cotton") {
            offset = offset * (-1);  
         }   
         
         // Compute new price and create a corresponding option
         var newPrice = price - offset;
         var newOption = document.createElement("option");
         var optionText = document.createTextNode(size + " ($" + newPrice + ")");
         newOption.appendChild(optionText);
         newOption.setAttribute("value", size + ":" + newPrice + ":" + shipping);
         
         if (i == currSelectionIdx) {
            newOption.selected = true;
         }
         
         // Add the option to the drop-down
         form.size.appendChild(newOption);
      }
   }
   
   // Save selected paper type
   lastPaperType = paperSelection;
   
   return false;
}