import flash.display.Sprite;
import flash.events.Event;

//Create grid sets
function CreateGridArray(input_col, input_row) {
  var arr = new Array(input_col);
  for (var i = 0; i < arr.length; i++) {
    arr[i] = new Array(input_row);
  }
  return arr;
}

//Set-up 1st grid image
var StartGrid:Array = new Array();

var grid_size = 10;
var col = Math.round(stage.stageWidth/grid_size);
var row = Math.round(stage.stageHeight/grid_size);

StartGrid = CreateGridArray(col, row);

for (var i = 0; i < col; i++) {
    for (var j = 0; j < row; j++) {
        var r:Number = Math.random();
        if (r < 0.2){
            StartGrid[i][j] = 1;
        }
        else{
            StartGrid[i][j] = 0;
        }
    }
}

var sp:Sprite = new Sprite();
stage.addChild(sp);

//Frame Enter Start
stage.addEventListener(Event.ENTER_FRAME, onLoop);

function onLoop(e:Event){
    var NewGrid:Array =  new Array();

    //Print grid pattern
    for (var i = 0; i < col; i++){
        for (var j = 0; j < row; j++){
            if(StartGrid[i][j] == 1){
                sp.graphics.beginFill(0x000000, 1);
                sp.graphics.drawRect(i*grid_size, j*grid_size, grid_size, grid_size);
                sp.graphics.endFill();
            }
        }
    }

    //Setup & simulate 2nd grid
    NewGrid = CreateGridArray(col, row);

    for (i = 0; i < col; i++){
        for (j = 0; j < row; j++){
            //exception for edge
            var cell_state = StartGrid[i][j];

            //check for 1 cell
            var nearbySumUp = NearbyCount(i,j,StartGrid);

              if (cell_state == 0 && nearbySumUp == 3) {
                NewGrid[i][j] = 1;
              } else if (cell_state == 1 && (nearbySumUp < 2 || nearbySumUp > 3)) {
                NewGrid[i][j] = 0;
              } else {
                NewGrid[i][j] = cell_state;
              }
        }
    }

    StartGrid = NewGrid;
}

function NearbyCount(i,j,GridName){
  var sum = 0;

 //Sum up all nearby cells (with egde prevent)
  for (var i = -1; i < 2; i++) {
    for (var j = -1; j < 2; j++) {
        var col= (col + x + i) % col;
        var row = (row + y + j) % row;
      sum += GridName[col][row];
    }
  }

  sum -= GridName[x][y]; //remove itself

  return sum;
}