<?xml version="1.0" encoding="utf-8"?>
  <mx:Application        xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute"
          initialize="init();"
          verticalScrollPolicy="off" horizontalScrollPolicy="off" 
          backgroundImage="@Embed('student-twitter-swarm-images-bg.jpg')" backgroundAttachment="fixed" 
          width="900" height="600">
          
          <mx:Script>
                  <![CDATA[
                          import mx.controls.Label;
                          import mx.rpc.events.ResultEvent;
                          import flash.utils.clearInterval;
                          import flash.utils.setInterval;
                          import mx.controls.Image;
                          import mx.controls.Alert;
                          
                          private var screenWidth:int = 900,
                                                  screenHeight:int = 600;
                          
                          private var worldObjects:Array;
                          private var trees:Array;
                          private var boids:Array;
                          
                  // Initialisation
                          private function init ():void {
                                  // Is called at startup and starts the initialisation process.
                                  
                                  Security.loadPolicyFile('student-twitter-crossdomain.xml');
                                  getEmotions();
                          }
                          private function getEmotions ():void {
                                  // Calls for the retrieval of the emotions.
                                  
                                  emo.url = "student-twitter-emotions.xml";
                                  emo.send();
                             }
                             
                             [Bindable]
                          private var xEmotions:XML;
                          private var emotions:Array = [], colors:Array = [];
                          private function setEmotions (event:ResultEvent):void { 
                                  // When the emotions have been retrieved from the server, 
                                  // this function is called.
                                  // When the emotions and colors have been extracted, the
                                  // trees are added to the application.
                                  
                                  xEmotions = event.result as XML;
                                  
                                  var emotionList:XMLList = xEmotions.emotion;
                                                          
                                  for(var i:int = 0; i < emotionList.length(); i++) {
                                          emotions[emotions.length] = extractEmotion(emotionList[i]);
                                          colors[colors.length] = extractColor(emotionList[i]);
                                  }
                                  
                                  addTrees();
                          }
                             
                          public function extractEmotion (emotion:XML):Array {
                                  // Extracts the emotion and associated words from the XML object.
  
                                  var words:XMLList = emotion.words.word;
                                   
                                  var word:XML;
                                  var result:Array = [emotion.attribute("name")];
                                  for each(word in words) {
                                          result[result.length] = word.toString();
                                  } 
                                  return result;
                          }
                             
                          public function extractColor (emotion:XML):Array {
                                  // Extracts the three color values from the XML object.
                                  
                                  var color:XMLList = emotion.color;
                                  return [parseFloat(color[0].attribute("red")), 
                                                  parseFloat(color[0].attribute("green")), 
                                                  parseFloat(color[0].attribute("blue"))]
                          }
                                                     
                             private function addTrees():void {
                                  // The trees are added at the designated x and y coordinates and mood.
                                  // When the trees are added, the initialisation is complete.
  
                                     trees = [];
                                     addTree(242, 125, "happy");
                                     addTree(737, 460, "tired");
                                     addTree(819, 68, "love");
                                     addTree(489, 360, "angry");
                                     addTree(138, 450, "sad");
                             }
                             [Embed(source="student-twitter-swarm-images-ring.png")]        public var treetop:Class;
                             private function addTree(x:int, y:int, mood:String):void {
                                  // An image is created here, because it can only be added to the 
                                  // screen in this file. The variable above the function makes sure
                                  // that the image is embedded in the compiled application.
                                  // An event listener is added so the user can shake the tree and 
                                  // the tree object is created.
                                  
                                     var treeImage:Image = new Image();
                                  this.addChild(treeImage);
                                  treeImage.source = treetop;
                                  
                                  treeImage.addEventListener(MouseEvent.CLICK, this.shakeTree);
                                  
                                     var tree:student_twitter_swarm_Tree = new student_twitter_swarm_Tree(x, y, treeImage, mood);
                                     trees.push(tree);
                             }
                             
                             private function shakeTree (event:Event):void {
                                  // If the simulation is running then find the right tree and tel 
                                  // it to shake.
  
                                     if (simRunning) {
                                             for(var i:int = 0; i < trees.length; i++) { 
                                                  if (trees[i].getImage() == event.currentTarget) {
                                                          trees[i].shake(boids);
                                                  }
                                          }
                                     }
                          }
                             
                  // Twitter-contact Initiation                           
                          private function goAll ():void {
                                  // If someone pushes the Latest Tweets button then set user to 
                                  // All and retrieve the tweets.
                                  
                                  usernameBox.text = "All"; 
                                     getTweets();
                           }
                             
                             private var simRunning:Boolean = false;
                             private function simClick ():void {
                                  // Changes the Go button and starts/stops the simulation.
  
                                     if (usernameBox.enabled) {
                                             getTweets();
                                             simButton.enabled = false;
                                     } else if (!simRunning) {
                                             simButton.label = "Pause";
                                             start();
                                             simRunning = true;
                                     } else if (simRunning) {
                                             simButton.label = "Start";
                                             stop();
                                             simRunning = false;
                                     }
                             }
                             
                            private function getTweets ():void {
                                  // Requests the xml for the current user.
  
                                  srv.url = "student-twitter-tweets.php?user=" + usernameBox.text; 
                                  srv.send();
                             }
                             
                  // Post server-contact initialisation 
                             [Bindable]
                          private var xData:XML;
                          private function newTweets (event:ResultEvent):void { 
                                  // Called when the tweets have been retrieved from the server.
  
                                  xData = event.result as XML;
                                  addBoids(xData);
                                  simButton.enabled = true;
                          }
                          
                          private function addBoids (data:XML):void {
                                  // Adds a boid for each tweet in the data.
                                  // The array of embedded images is the sequence for the AnimatedImage
                                  // After the boids have been added the boids are compared to each other 
                                  // to calculate which other boids they should be attracted to.
  
                                  var tweets:XMLList = data.status;
                                  boids = [];
  
                                  if (boids.length > 0) { 
                                          stop(); 
                                  }
                                  
                                  usernameBox.enabled = false;
                                  goAllButton.enabled = false;
                                  
                                    [Embed(source="student-twitter-swarm-images-orb-0.png")]        var frame0:Class;
                                  [Embed(source="student-twitter-swarm-images-orb-1.png")]        var frame1:Class;
                                  [Embed(source="student-twitter-swarm-images-orb-2.png")]        var frame2:Class;
                                  [Embed(source="student-twitter-swarm-images-orb-3.png")]        var frame3:Class;
                                  var anim:Array = [];
                                  anim[0] = frame0;
                                  anim[1] = frame1;
                                  anim[2] = frame2;
                                  anim[3] = frame3;
                                  
                                  var tweet:student_twitter_swarm_Tweet;
                                  for(var i:int = 0; i < tweets.length(); i++) {
                                          tweet = new student_twitter_swarm_Tweet(tweets[i], emotions, colors);
                                          addBoid(tweet, anim);
                                  }
                                  
                                  for(var r:int = 0; r < boids.length; r++) {
                                          boids[r].calculateSimilarities(boids);
                                  }
                                  
                                  simClick();
                          }
                          
                             private function addBoid (tweet:student_twitter_swarm_Tweet, anim:Array):void {        
                                  // Adding a boid requires an image that is added to the screen and
                                  // interactivity with the user to display the message attached to the boid.
                          
                                     var boidImage:Image = new Image();
                                  this.addChild(boidImage);
                                  
                                  var boid:student_twitter_swarm_Boid = new student_twitter_swarm_Boid(boidImage, messagePanel, tweet, anim);
                                  boidImage.addEventListener(MouseEvent.CLICK, this.hideAllTweets);
                                  boidImage.addEventListener(MouseEvent.CLICK, boid.showTweet);
                                  boids.push(boid);
                             }
                             
                             private function hideAllTweets (event:MouseEvent):void {
                                     for(var i:int = 0; i < boids.length; i++) {
                                          boids[i].hideTweet();
                                  }
                             }
                             
                  // Animation
                             private var animID:uint;
                             private function start ():void {
                                  // Starts the timer that will move the boids.
  
                                     animID = setInterval(moveBoids, 50, boids, boids.length);
                             }
                             private function stop ():void {
                                  // Removes the timer that moves the boids.
                                  
                                  clearInterval(animID);
                          }
                             
                             private        function moveBoids(boids:Array, numBoids:int):void {
                                  // Each boid is subject to these five forces that drive its behaviour.
                                  // When the forces have changed the direction and speed (vector) of the
                                  // boid the images need to be moved. So the function displayWorld() is 
                                  // called.
          
                                  for(var i:int = 0; i < boids.length; i++) {
                                          boids[i].alignment(boids, 300);
                                          boids[i].cohesion(boids, 400);
                                          boids[i].separation(boids, 15);
                                          boids[i].treeSeeking(trees, 200);
                                          boids[i].nesting(trees);
                                  }
                                  displayWorld();
                          }
                          
                          private function displayWorld ():void {
                                  // Moves the boids to their new coordinates using the current vector.
  
                                  for(var r:int = 0; r < boids.length; r++) {
                                          boids[r].move();
                                          boids[r].moveImage(screenWidth, screenHeight)
                                  }
                          }
                  ]]>
          </mx:Script>
  
          <mx:ApplicationControlBar dock="true">
                  <mx:Button id="goAllButton" click="goAll();" label="Newest Tweets"/>
                  <mx:Label  text="or Username:"/>
                  <mx:TextInput id="usernameBox" text="default"/>
                  <mx:Button id="simButton" click="simClick();" label="Go"/>
          </mx:ApplicationControlBar>
          
          <mx:HTTPService id="emo" result="setEmotions(event);" resultFormat="e4x"/>
          <mx:HTTPService id="srv" result="newTweets(event);" resultFormat="e4x"/>
  
          <mx:Panel id="messagePanel" x="500" y="400" width="387" height="155" layout="absolute" fontSize="13" visible="false">
                  <mx:Image id="profilePic" x="10" y="10" width="48" height="48"/>
                  <mx:Text  id="tweetLabel" x="66" y="10" width="290" height="75"/>
                  <mx:Label id="moodLabel" x="66" y="85" width="290" height="20"/>
          </mx:Panel>
  
  </mx:Application>