// 010912 quizcode.js 
// using copy of questions array, selects one at a time and displays it
// restart(), getquestion() includes slideup/down jquery animation,
// displayquestion(), resetquestion(), shakeup(), soundplayer()
// correctanswer()function, value of answer and what to do with answer is in game.html file
//-----------------------
// 050810 - Disable enter key - www.webcheatsheet.com method
// 311013 - Allow for caeser shift encrypted questions, disable realquestionnumber variable
// 020114 - converted to mp3 

function stopRKey(evt) {
  var evt = (evt) ? evt : ((event) ? event : null);
  var node = (evt.target) ? evt.target : ((evt.srcElement) ? evt.srcElement : null);
  if (evt.keyCode == 13) {return false;}
}
document.onkeypress = stopRKey;

answer="";
correctanswer=0;        // if answer correct

// qloaded=1;        // stop answering same question twice

distractornum=0;  // 020612 initialise global for no. of distractors 4 or 5
score=0;
spinwin=0;
if(typeof gametitle!='string'){gametitle=''} // 150211 - use gametitle if available

function decodequestion(qdecode){
  //281013 - encrypted questions in millquestenc.js are decoded via decodequestion() fn
  decodedq='';   //initialise decoded question string
  // only decode letters
  var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz[\]^"; 

for (var i=0;i<qdecode.length;i++)
    {var ch = qdecode.charAt(i);  // get each letter in turn

     if (alphabet.indexOf(ch) != -1)  // not a letter ignore
        {
         chnum=ch.charCodeAt(0)-cshift; // get ASCII code of letter and cshift from questions file
         ch=String.fromCharCode(chnum);  // convert ASCII code back to letter
        }

     decodedq=decodedq+ch;  //build decoded string back up
    }
}

function restart(){
   // decrypt question bank, if encrypted
   for (var i=1;i<=questions.length-1;i++)
       {
        // 281013 - added to allow for encrypted questions
        if (typeof cshift != "undefined")  // only decode if a shift used in questions file
           {if (cshift != 0)
               {
	        decodequestion(questions[i]); //call question decoding function
	        questions[i]=decodedq;
	       }
	    }
        }
  // end decrypt         
    
  q=new Array();  // initialise q array
 if(document.getElementById('questionbutton'))  // use only if it exists
   {document.getElementById('questionbutton').style.visibility='visible';}
  
// ensure additional gold box is empty whenever this page is loaded to fix backspace trick
//  document.getElementById('scorebox').innerHTML=score;
  choice=''; //initialise answer letter to null.
  document.getElementById('qdiv').style.display='none'; // hide to start
  document.getElementById('stem').style.visibility='hidden';
}

function getaquestion(){
  if(q.length-1<1)  // if all questions are used, start again
    {q=questions.slice(0);}
    
  // get a questionnumber at random from q
  questionnum=Math.floor(Math.random()*(q.length-1))+1; //add 1 cos q[0] is empty
  
//           qloaded=1;  //new question

  $("#qdiv").slideUp("normal",displayquestion);  // slide and display new question
  $("#qdiv").slideDown("normal");
}

function displayquestion(){

   testsplit=q[questionnum].split('~');  // split question into array elements

   // 020612 4/5 distractors
   if ((testsplit[5]=='A')||(testsplit[5]=='B')||
       (testsplit[5]=='C')||(testsplit[5]=='D'))
        {distractornum=4;//  only 4 distractors, hide 5th 
         document.getElementById('responseE').style.display='none';
        }  
   else {distractornum=5;
         document.getElementById('responseE').style.display='block';
        }

   shakeup();     // randomise distractor locations
   
   // find true question no. by matching question contents to original array
   errorflag=1;

   for (var i=1;i<=questions.length-1;i++)
      {if(q[questionnum]==questions[i])
         {errorflag=0;
          realquestionnumber=i; // the actual question number in questions array
         }
      }
   
  linkq=''; // assign no links to linkq
  
  // load question into cells
  document.getElementById('stem').innerHTML='Question '+realquestionnumber+": "+testsplit[0];
  document.getElementById('responseAlink').innerHTML='A) '+testsplit[1];
  document.getElementById('responseBlink').innerHTML='B) '+testsplit[2];
  document.getElementById('responseClink').innerHTML='C) '+testsplit[3];
  document.getElementById('responseDlink').innerHTML='D) '+testsplit[4];
  
  if (distractornum==5)
      {document.getElementById('responseElink').innerHTML='E) '+testsplit[5];}
      
  answer=testsplit[distractornum+1];    
  difficulty=testsplit[distractornum+2];
  gamelevel=testsplit[distractornum+3];
  hint=testsplit[distractornum+4];
  linkq=testsplit[distractornum+5]

  q.splice(questionnum,1); // remove current question from array
   
  resetquestion();        
}

function resetquestion(){

  choice=''; //initialise answer letter to null.
  
  // hide 'questionbutton' and 'bankgold' button
   if(document.getElementById('questionbutton'))  // use only if it exists
     {document.getElementById('questionbutton').style.visibility='hidden';}

  
  //  make questions visible and style distractors 
  document.getElementById('stem').style.visibility='visible';
  
  // 200810 - reset background to black for each new question
  document.getElementById('responseA').style.backgroundColor='black';
  document.getElementById('responseB').style.backgroundColor='black';
  document.getElementById('responseC').style.backgroundColor='black';
  document.getElementById('responseD').style.backgroundColor='black';
  document.getElementById('responseE').style.backgroundColor='black';
}

function shakeup(){
// function by <chris.wright@ mail.com> to shuffle the answers in some QGM games
// input array testsplit[], [0]=Question, [1]-[4]=possible answers, [5]=key A-E to correct answer
var abcde="ABCDE";
var i; // need to declare this to protect other counters
         for(i=1; i<=distractornum; i++){
                 var aa=testsplit[distractornum+1]; //the original answer position
                 var x=aa.charCodeAt(0)-64; // convert ASCII code for answer into number in range 1-4
                 var newplace=Math.ceil(Math.random()*distractornum);
                 var temp=testsplit[newplace];
                 testsplit[newplace]=testsplit[i];
                 testsplit[i]=temp; //swap index with newplace
                 if(i==x){testsplit[distractornum+1]=abcde.substring(newplace-1,newplace);}
                // if moving the answer, correct the answer flag
                 if(newplace==x){testsplit[distractornum+1]=abcde.substring(i-1,i);} // if displacing the answer, adjust the answer flag
         }

}

function soundplayer(x){  // use new html audio tag to play mp3's
   document.getElementById("sndplayer").src=x+".mp3";
   document.getElementById("sndplayer").play();
}