//ZOMG! jQuery pong!! W00t, yeah.
//Based on the one by a guy named Ben White @ benwhite@columbus.rr.com
//jQuery'd by Ben Ogle. 

(function($){  
  $.fn.pong = function(ballImage, options) {
    
    var defaults = {
      targetSpeed: 30,  //ms
      ballAngle: 45,    //degrees
      ballSpeed: 8,     //pixels per update
      compSpeed: 5,     //speed of your opponent!!
      playerSpeed: 5,   //pixels per update
      difficulty: 5,
      width: 400,       //px
      height: 300,      //px
      paddleWidth: 10,  //px
      paddleHeight: 40, //px
      paddleBuffer: 1,  //px from the edge of the play area
      ballWidth: 14,    //px
      ballHeight: 14,   //px
      playTo: 10        //points
    }
    
    var opts = $.extend(defaults, options);
    
    ////functions!
    
    function PositionBall(bolSide, gameData, leftPaddle, rightPaddle, ball, score) {
      
      if (bolSide) {
        gameData.x = opts.width - opts.paddleWidth - opts.paddleBuffer - opts.ballWidth - 10;
      }
      else {
        gameData.x = opts.paddleWidth + opts.paddleBuffer + 10;
      }
      gameData.y = Math.round(Math.random() * (opts.height - ball.height()));
      
      ball.css('left', gameData.x);
      ball.css('top', gameData.y);
      
      if (bolSide != (0>Math.cos(opts.ballAngle*Math.PI/180)>0)) {
        opts.ballAngle += 180
      }
      
      ball.css('visibility', 'visible');
    }
    
    function UpdateScore(bolUser, gameData, leftPaddle, rightPaddle, ball, score, msg) {
      
      if (bolUser){
        gameData.playerScore++;
      }else{
        gameData.compScore++;
      }
      
      score.html('browser ' + gameData.compScore + ' | ' + 'you ' + gameData.playerScore);
      
      if (gameData.playerScore == opts.playTo || gameData.compScore == opts.playTo) {
        ball.css('visibility', 'hidden');
        gameData.gameOver = true;
        
        if(gameData.playerScore == opts.playTo)
          score.append('; you win!');
        else
          score.append('; you lose :(');
          
      } else {
        PositionBall(bolUser, gameData, leftPaddle, rightPaddle, ball, score);
      }
    }
    
    ///Is run by the setTimeout function. Updates the gameData object. 
    function Update(gameData, leftPaddle, rightPaddle, ball, score, msg) {
      
      if (gameData.gameOver) {
        msg.html('click to start!');
        return;
      }
    
      msg.html('press ESC to stop');
      
      // Dynamically Adjust Game Speed
    
      var tmpDelay = new Date();
      var Diff = tmpDelay.valueOf() - gameData.delay.valueOf() - opts.target;
      gameData.speed += (Diff > 5)?-1:0;
      gameData.speed += (Diff < -5)?1:0;
      gameData.speed = Math.abs(gameData.speed);
      gameData.delay = tmpDelay;
    
      setTimeout(function(){Update(gameData, leftPaddle, rightPaddle, ball, score, msg)}, gameData.speed);
    
      //	MoveBall
    
      var d = opts.ballAngle * Math.PI / 180;
      gameData.y += Math.round(opts.ballSpeed*Math.sin(d));
      gameData.x += Math.round(opts.ballSpeed*Math.cos(d));
      var VB = 180-opts.ballAngle;
      var HB = 0-opts.ballAngle;
    
      //	Move Computer
    
      var LeftTop = parseInt(leftPaddle.css('top'));
      var LeftCenter = (opts.paddleHeight/2) + LeftTop
    
      if (Math.cos(d) > 0 || (gameData.x > opts.width/(2-(gameData.compAdj/(opts.difficulty*10))))) {
        var Center = (opts.height/2);
      } else {
        var BallTop = gameData.y;
        var Center = (opts.ballHeight/2) +BallTop;
      }
      var MoveDiff = Math.abs(Center - LeftCenter);
      if (MoveDiff > opts.compSpeed)
        MoveDiff = opts.compSpeed;
        
      if (Center > LeftCenter) 
        LeftTop += MoveDiff;
      else 
        LeftTop -= MoveDiff;

      if (LeftTop < 1)
        LeftTop = 1;
        
      if ((LeftTop+opts.paddleHeight+1) > opts.height) {
        LeftTop = opts.height - opts.paddleHeight - 1;
      }
      
      leftPaddle.css('top', LeftTop+'px');
    
      //	Move Player
    
      var RightTop = parseInt(rightPaddle.css('top'));
      if (gameData.up) 
        RightTop -= opts.playerSpeed;
      if (gameData.down) 
        RightTop += opts.playerSpeed;
  
      if (RightTop < 1)
        RightTop = 1;
      if ((RightTop+opts.paddleHeight+1) > opts.height) 
        RightTop=opts.height-opts.paddleHeight-1;

      rightPaddle.css('top', RightTop+'px');
    
      //	Check Top/Bottom/Left/Right
    
      if (gameData.y < 1) {
        gameData.y = 1;
        opts.ballAngle = HB;
      }
      
      if (gameData.y > opts.height-opts.ballHeight) {
        gameData.y = opts.height-opts.ballHeight;
        opts.ballAngle = HB;
      }
      
      if (gameData.x < 1) {
        gameData.x = 1;
        opts.ballAngle = VB;
        gameData.compAdj -= opts.difficulty;
        
        UpdateScore(true, gameData, leftPaddle, rightPaddle, ball, score, msg);
      }
      
      if (gameData.x > opts.width-opts.ballWidth) {
        gameData.x=opts.width-opts.ballWidth;
        opts.ballAngle=VB;
        UpdateScore(false, gameData, leftPaddle, rightPaddle, ball, score, msg);
      }
    
      //	Check Left Paddle
    
      var MaxLeft = opts.paddleWidth + opts.paddleBuffer;
      if (gameData.x < MaxLeft) {
        if (gameData.y < (opts.paddleHeight + LeftTop) && (gameData.y+opts.ballHeight) > LeftTop) {
          gameData.x = MaxLeft;
          opts.ballAngle = VB;
          gameData.compAdj++;
        }
      }
    
      //	Check Right Paddle
    
      var MaxRight = opts.width - opts.ballWidth - opts.paddleWidth - opts.paddleBuffer;
      if (gameData.x > MaxRight) {
        if (gameData.y < (opts.paddleHeight + RightTop) && (gameData.y+opts.ballHeight) > RightTop) {
          gameData.x = MaxRight;
          opts.ballAngle = VB;
        }
      }
    
      ball.css('top', gameData.y);
      ball.css('left', gameData.x);
    
      if (gameData.compAdj < 0){
        gameData.compAdj = 0;
      }
    }
    
    function Start(gameData, leftPaddle, rightPaddle, ball, score, msg) {
      
      if (gameData.gameOver) {
        gameData.gameOver = false;
        gameData.playerScore = -1;
        gameData.compScore = -1;
        setTimeout(function(){Update(gameData, leftPaddle, rightPaddle, ball, score, msg)}, gameData.speed);
        UpdateScore(false, gameData, leftPaddle, rightPaddle, ball, score, msg);
        UpdateScore(true, gameData, leftPaddle, rightPaddle, ball, score, msg);
      }
    }
  
    return this.each(function() {
      
      var gameData = {
        up: false,        //Down key pressed?
        down: false,      //Down key pressed?
        x: 0,		//Ball X Pos
        y: 0,	        //Ball Y Pos
        compAdj: 0,	//Computer Adjust
        compScore: 0,	//Computer Score
        playerScore: 0,	//Player Score
        speed: 30,	//Actual Game Speed (Dynamic)
        gameOver: true,
        delay: new Date()
      }
      
      var $this = $(this);
      
      function keyDownEvent(event){
        switch (event.keyCode) {
          case 38: //Up Arrow
            gameData.up = true;
            break;
          case 40: //Down Arrow
            gameData.down = true;
            break;
          case 27: //Escape
            $this.children(".ball").css('visibility', 'hidden');
            gameData.gameOver = true;
            break;
        }
        return false;
      }
      
      function keyUpEvent(event){
        switch (event.keyCode) {
          case 38: //Up Arrow
            gameData.up = false;
            break;
          case 40: //Down Arrow
            gameData.down = false;
            break;
        }
        return false;
      }
      
      $this.css('background', '#000');
      $this.css('position', 'relative');
      
      $this.append('<textarea class="field" style="position:absolute;background:#000;border:0;top:-9999; left:-9999; width:0;height0;"></textarea>');
      $this.append('<div class="score" style="position:relative;color:#ffffff; font-family: sans-serif; text-align: center; font-weight: bold;">browser 0 | you 0</div>');
      $this.append('<div class="leftPaddle" style="position:absolute;background-color:#ffffff;"></div>');
      $this.append('<div class="rightPaddle" style="position:absolute;background-color:#ffffff;"></div>');
      $this.append('<img src="'+ballImage+'" class="ball" style="position:absolute;visibility:hidden;">');
      $this.append('<div class="msg" style="position:absolute; font-size: 8pt; color:#fff; bottom: 2px; right: 2px;"></div>');
      
      var leftPaddle = $this.children('.leftPaddle');
      var rightPaddle = $this.children('.rightPaddle');
      var ball = $this.children('.ball');
      var score = $this.children('.score');
      var msg = $this.children('.msg');
      var field = $this.children('.field');
      
      field.keydown( keyDownEvent );
      field.keyup( keyUpEvent );
      
      //field.css('width', 200);
      //field.css('height', 20);
      
      //initialize all
      $this.css('width', opts.width);
      $this.css('height', opts.height);

      leftPaddle.css('width', opts.paddleWidth);
      leftPaddle.css('height', opts.paddleHeight);
      leftPaddle.css('left', opts.paddleBuffer);
      leftPaddle.css('top', Math.round(1+(Math.random()*(opts.height-opts.paddleHeight-2))) );

      rightPaddle.css('width', opts.paddleWidth);
      rightPaddle.css('height', opts.paddleHeight);
      rightPaddle.css('left', opts.width - opts.paddleWidth - opts.paddleBuffer);
      rightPaddle.css('top', Math.round(1+(Math.random()*(opts.height-opts.paddleHeight-2))) );

      ball.css('width', opts.ballWidth);
      ball.css('height', opts.ballHeight);
      
      gameData.speed = opts.targetSpeed;
      Update(gameData, leftPaddle, rightPaddle, ball, score, msg);
      
      $this.click(function(){
        field.focus();
        Start(gameData, leftPaddle, rightPaddle, ball, score, msg);
      })
    });  
  };  
})(jQuery);