/*==============================================================================

Application:   Utility Function
Author:        John Gardner

Modified:      Paul Carthy

Notes:         Based on postcode checker, the code base has been added to to allow
               user feedback and matching postcode validation. 
              
  
Parameters:    validatePostCode - none
               toCheck - postcodeto be checked. 
                   
------------------------------------------------------------------------------*/

/* ------------------ Edit this area only ------------------------------------*/
function validatePostCode () {
  var thePostCode = document.search.postcode.value;
  if (thePostCode == null || thePostCode == "")
  {
   jAlert('You must enter a Postcode to Carry on', 'Postcode Missing');		// Edit for missing postcode
  }
  else
  {
   var pcode = checkPostCode (thePostCode);
   if (pcode) 
   {
    if (matchPostcode (pcode))
     window.location = 'http://www.pizzanation.co.uk/redirect.php';  					// Edit for correct postcode redirect
    else
     window.location = 'http://www.pizzanation.co.uk/sorry.html';   					// Edit for incorrect postcode redirect
   } 
   else 
   { 
    jAlert('You entered an invalid Postcode', 'Postcode Error');		// Edit for incorrectly formatted postcode
   };
  }
  document.search.postcode.focus();
  return false;
}

function matchPostcode(toCheck) {
 var pcodeArray = toCheck.split(" ");
 var outerCode = pcodeArray[0].toUpperCase();
 var innerCode = pcodeArray[1].toUpperCase();
 
 var matched = false;
 
 if(outerCode == 'TQ1') matched = true;						// Edit by adding or deleting new matches
 if(outerCode == 'TQ2') matched = true;
 if(outerCode == 'TQ3') matched = true;
 if(outerCode == 'TQ4') matched = true;
 if(outerCode == 'TQ5') matched = true;
 if(outerCode == 'TQ6') {
  if(innerCode[0] == '9') matched = true;
 }

 return matched;
}


/* ------------------- Do not change below ----------------------------------*/
function checkPostCode (toCheck) {

  // Permitted letters depend upon their position in the postcode.
  var alpha1 = "[abcdefghijklmnoprstuwyz]";                       // Character 1
  var alpha2 = "[abcdefghklmnopqrstuvwxy]";                       // Character 2
  var alpha3 = "[abcdefghjkpmnrstuvwxy]";                         // Character 3
  var alpha4 = "[abehmnprvwxy]";                                  // Character 4
  var alpha5 = "[abdefghjlnpqrstuwxyz]";                          // Character 5
  
  // Array holds the regular expressions for the valid postcodes
  var pcexp = new Array ();

  // Expression for postcodes: AN NAA, ANN NAA, AAN NAA, and AANN NAA
  pcexp.push (new RegExp ("^(" + alpha1 + "{1}" + alpha2 + "?[0-9]{1,2})(\\s*)([0-9]{1}" + alpha5 + "{2})$","i"));
  
  // Expression for postcodes: ANA NAA
  pcexp.push (new RegExp ("^(" + alpha1 + "{1}[0-9]{1}" + alpha3 + "{1})(\\s*)([0-9]{1}" + alpha5 + "{2})$","i"));

  // Expression for postcodes: AANA  NAA
  pcexp.push (new RegExp ("^(" + alpha1 + "{1}" + alpha2 + "{1}" + "?[0-9]{1}" + alpha4 +"{1})(\\s*)([0-9]{1}" + alpha5 + "{2})$","i"));
  
  // Exception for the special postcode GIR 0AA
  pcexp.push (/^(GIR)(\s*)(0AA)$/i);
  
  // Standard BFPO numbers
  pcexp.push (/^(bfpo)(\s*)([0-9]{1,4})$/i);
  
  // c/o BFPO numbers
  pcexp.push (/^(bfpo)(\s*)(c\/o\s*[0-9]{1,3})$/i);
  
  // Overseas Territories
  pcexp.push (/^([A-Z]{4})(\s*)(1ZZ)$/i);

  // Load up the string to check
  var postCode = toCheck;

  // Assume we're not going to find a valid postcode
  var valid = false;
  
  // Check the string against the types of post codes
  for ( var i=0; i<pcexp.length; i++) {
    if (pcexp[i].test(postCode)) {
    
      // The post code is valid - split the post code into component parts
      pcexp[i].exec(postCode);
      
      // Copy it back into the original string, converting it to uppercase and
      // inserting a space between the inward and outward codes
      postCode = RegExp.$1.toUpperCase() + " " + RegExp.$3.toUpperCase();
      
      // If it is a BFPO c/o type postcode, tidy up the "c/o" part
      postCode = postCode.replace (/C\/O\s*/,"c/o ");
      
      // Load new postcode back into the form element
      valid = true;
      
      // Remember that we have found that the code is valid and break from loop
      break;
    }
  }
  
  // Return with either the reformatted valid postcode or the original invalid 
  // postcode
  if (valid) {return postCode;} else return false;
}