var lastSelection = null;
var nSwaps = 0;

window.onload = fnInit;

function fnInit()
{
  var oRow;
  var iRow, iCol;

  for (iRow = 0; iRow < 3; iRow++) {
	oRow = oTable.insertRow();
    for (iCol = 0; iCol < 3; iCol++) {
	  oRow.insertCell();
    }
  }
 
  scrambleCells();
}

function getRandom(maxValue) {
  // Create an instance of the current date.
  var now = new Date();

  // Create a random number.
  var num = now.getTime() * now.getSeconds() * Math.random();

  // Cut random number to an integer value between 0 and maxValue, inclusive.
  return Math.round(num % maxValue);
}

function scrambleCells()
{
  var arr, nIndex, nRnd, arrCount, bFound, iRow, iCol;

  arr = new Array(9);
    
  // Fill the array with values from 0 - 8 in a random order.
  for (nIndex = 0; nIndex < 9; nIndex++) {
    bFound = 1;

	// Generate a random integer value from 0 - 8.
    while (bFound == 1) {
      bFound = 0;
      nRnd = getRandom(8);

      // Go back through the array and make sure the number isn't already there.
      for (arrCount = nIndex; arrCount >= 0; arrCount--) {
        if (arr[arrCount] == nRnd) {
          bFound = 1;  // Oops!  Found it, try again.
        } // end if
      }  // end for

    }  // end while

    arr[nIndex] = nRnd;

  }  // end for

  // Populate the table
  nIndex = 0;
  for (iRow = 0; iRow < 3; iRow++) {
    theRow=oTable.rows(iRow);
	for (iCol = 0; iCol < 3; iCol++) {
      theRow.cells(iCol).innerHTML = "<img src=puzzle/1/p" + arr[nIndex] + ".gif>"
	  nIndex++;
    }
  }

  // Deselect all the cells in case there was a winner in the last game.
  nIndex = 0;
  for (iRow = 0; iRow < 3; iRow++) {
    theRow=oTable.rows(iRow);
  	for (iCol = 0; iCol < 3; iCol++) {
      deselectCell(oTable.rows(iRow).cells(iCol));
      nIndex++;
    } // end for
  }  // end for

  winnerText.innerText = "";
  nSwaps = 0;
  numSwaps.innerText = nSwaps;
}

function onclickCell()
{
  var e, c;
  
  // Do not accept clicks if there's been a winner.
  if (winnerText.innerText != "") {
    window.event.cancelBubble = true;
	return;
  }
  
  e = window.event.srcElement;
  c = findCell(e);

  if (c != null) {
    if (lastSelection == null) {
      selectCell(c);
      lastSelection = c;
	}
	else {
	  if (c == lastSelection) {
	    deselectCell(lastSelection);
	  }
	  else {
	    c.swapNode(lastSelection);
        deselectCell(lastSelection);
	    nSwaps += 1;
	    numSwaps.innerText = nSwaps;
		checkWinner();
	  }
	  lastSelection = null;
    }
  }
  window.event.cancelBubble = true;
} 

function findCell(e)
{
  if (e.tagName == "TD") {
    return e;
  }
  else if (e.tagName == "BODY") {
    return null;
  }
  else {
    return findCell(e.parentElement);
  }
}

function selectCell(c)
{
  c.runtimeStyle.backgroundColor = "red";
  c.runtimeStyle.color = "white";
}

function cancelSelect()
{
  if (lastSelection != null) {
    deselectCell(lastSelection);
    lastSelection = null;
  }
}

function deselectCell(c)
{
  c.runtimeStyle.backgroundColor = "white";
  c.runtimeStyle.color = "white";
}

function checkWinner()
{
  var bWinner = 1;  // Assume we have a winner.
  var nIndex = 0;
  var sFilename;
  
  for (iRow = 0; iRow < 3; iRow++) {
    theRow=oTable.rows(iRow);
	for (iCol = 0; iCol < 3; iCol++) {
      sFilename = theRow.cells(iCol).innerHTML;
	  sFilename = sFilename.substring(sFilename.length - 7, sFilename.length - 6);
      if (sFilename != nIndex) {
	    bWinner = 0;  // Had a mismatch, no winner.
	  }
	  nIndex++;
    }
  }
  
  if (bWinner == 1) {
    // Display the winner text.
    winnerText.innerHTML="<font color='red'><b>Winner!!!</b></font><br><br>Click the Scramble button to play again.";

	// Select all the cells, just to look cool for the winner.
	nIndex = 0;
    for (iRow = 0; iRow < 3; iRow++) {
      theRow=oTable.rows(iRow);
  	  for (iCol = 0; iCol < 3; iCol++) {
	    selectCell(oTable.rows(iRow).cells(iCol));
	    nIndex++;
      } // end for
    }  // end for
    
  }  // end if
}

oTable.onclick = onclickCell;
document.onclick = cancelSelect;