// global variables
var T="T",F="F"; // to avoid lots of quotes
var noRight=0; noWrong=0;

// mouseover functions classNames from style sheet
function wrong(){this.className="wrong";}
function wrongOver(){this.className="wrongOver";}
function right(){this.className="right";}
function rightOver(){this.className="rightOver";}

// this is the body onload function
function init(){
  var bdy=document.body;
  bdy.onresize=moveBox;
  bdy.onscroll=moveBox;
  box.style.visibility="visible";
  moveBox();
  if(document.location.search.search(/noRight *= *([0-9]*)/)>=0)
    noRight=parseInt("0"+RegExp.$1,10);
  if(document.location.search.search(/noWrong *= *([0-9]*)/)>=0)
    noWrong=parseInt("0"+RegExp.$1,10);
  boxNoRight.innerHTML=(noRight<100?"&nbsp;":"")+noRight;
  boxNoWrong.innerHTML=(noWrong<100?"&nbsp;":"")+noWrong;
}

// automate truth tables
function makeTable(prims,comps,data){ 
  var p=prims.length,c=comps.length,h,i,j;
  h='<table cellpadding="0" border="0" cellspacing="0"><tr>';
  for(j=0;j<p;j++){
    h=h+'<td align="center">&nbsp;&nbsp;&nbsp;'+prims[j]+'&nbsp;&nbsp;&nbsp;'; 
  }
  h=h+'<td rowspan="32" bgcolor="#000000" width="1"></td>';
  for(j=0;j<c;j++){
    h=h+'<td align="center">&nbsp;&nbsp;&nbsp;'+comps[j]+'&nbsp;&nbsp;&nbsp;'; 
  }
  h=h+'</tr><tr><td bgcolor="#000000" colspan="'+p+'" height="1"></td>';
  h=h+'<td bgcolor="#000000" colspan="'+c+'"></td></tr>';
  for(i=0;i<data.length;i++){
    h=h+'<tr>';
    for(j=0;j<p;j++)h=h+'<td align="center">'+data[i][j]+'';
    for(j=0;j<c;j++)h=h+'<td align="center">'+TFStr(data[i][p+j])+'';
    h=h+'';
  }
  h=h+'</table>';
  document.write(h);
}

// True - False questions
function doTF(me){
  if(me.innerHTML=="T ") me.innerHTML="F ";
  else if(me.innerHTML=="F ") me.innerHTML="T ";
  else{
    var range=document.selection.createRange();
    range.expand("word");
    if(range.text=="T " || range.text=="F ") me.innerHTML=" "+range.text;
  }
  if(me.innerHTML=="T " || me.innerHTML=="F "){
    if(me.innerHTML==me.value+" "){
      me.className='right';
      if(me.score!=1 && me.score!=-1) celebrate(me.score=1);
      me.correct=true;
    }else{
      me.className='wrong';
      if(me.score!=1 && me.score!=-1) celebrate(me.score=-1);
      me.correct=false;
    }
  }
}

function TFStr(v){
  return '<span class="wrong" style="cursor:default" value="'+v+'" onclick="doTF(this)"> T / F </span>';
} 

function TF(v){document.write(TFStr(v));}

// Multiple choice questions
function doMC(me){
  var shown=me.children[0]; choices=me.children[1];
  var source=event.srcElement;
  if(source.name=="help"){
    alert('Click one of the choices offered. If correct, your choice will appear in black.');
  }else{
    while(source!=me && source.name!="alt" && source.name!="shown") source=source.parentElement;
    if(source.name=="alt"){ 
      shown.innerHTML=source.innerHTML;
      shown.value=source.value;
      choices.style.display="none";
      mCMOut(shown);
      me.correct=(shown.value=="correct");
      if(me.score!=1 && me.score!=-1) celebrate(me.score=(me.correct?1:-1));
    }else if(source.name=="shown"){
      if(choices.style.display=="inline") choices.style.display="none";
      else choices.style.display="inline";
    }
  }
}

function mCMOver(my){
  if(my.value=="correct") my.className='rightOver';
  else my.className='wrongOver';
}

function mCMOut(my){
  if(my.value=="correct") my.className='right';
  else my.className='wrong';
}

function mCStr(text,answers,correct){
  var i,h;
  h='<span style="cursor:default" onclick="doMC(this)">';
  h=h+'<span name="shown" class="wrong" onmouseover="mCMOver(this)" onmouseout="mCMOut(this)">';
  h=h+text;
  h=h+'</span><span name="choices" ';
  h=h+'class="alt" style="display=none">';
  h=h+'<strong><span name="help"> ? </span></strong>';
  for(i=0;i<answers.length;i++){
    h=h+(i==0?' &lt ':' | ')+'<span name="alt"'+(i+1==correct?' value="correct"':'');
    h=h+'onmouseover="this.className='+"'altOver'"+'" onmouseout="this.className='+"'alt'"+'">';
    h=h+answers[i];
    h=h+'</span>'
  }
  h=h+' &gt</span></span>';
  return h;
}

function mC(text,answers,correct){document.write(mCStr(text,answers,correct));}


function moveBox(){
  box.style.pixelLeft=document.body.scrollLeft+document.body.offsetWidth-box.style.pixelWidth-40;
  box.style.pixelTop=document.body.scrollTop+document.body.offsetHeight-box.style.pixelHeight-40;
  box.style.zIndex=-1;
}


function celebrate(v){
  var mood;
  if(""+v=="1"){
    noRight+=1;
    mood=happy;
  }else{
    noWrong+=1;
    mood=sad;
  }
  mood.style.posLeft=document.body.scrollLeft+window.event.clientX-20;
  mood.style.posTop=document.body.scrollTop+window.event.clientY-20;
  if(window.event.clientY<document.body.offsetHeight/2) mood.style.posTop +=60; else mood.style.posTop -=60;
  mood.style.visibility="visible";
  mood.style.zIndex=-1;
  mood.filters.blendTrans.apply();
  mood.style.visibility="hidden";
  mood.filters.blendTrans.play();
  boxNoRight.innerHTML=(noRight<100?"&nbsp;":"")+noRight;
  boxNoWrong.innerHTML=(noWrong<100?"&nbsp;":"")+noWrong;
}