Emanuele Feronato

var game;

var gameOptions = {
	gameWidth: 750, 
	gameHeight: 750, 
	tileSize: 140, 
	fieldSize: 5
}

window.onload = function() {	
	game = new Phaser.Game(gameOptions.gameWidth, gameOptions.gameHeight);
     game.state.add("TheGame", TheGame);
     game.state.start("TheGame");
}

var TheGame = function(){};

TheGame.prototype = {
     preload: function(){
          game.stage.backgroundColor = 0x444444;
          game.load.image("tiles", "assets/sprites/tiles.png");
          game.load.spritesheet("arrows", "assets/sprites/arrows.png", 420, 420);     
     },
  	create: function(){
          game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
		game.scale.pageAlignHorizontally = true;
		game.scale.pageAlignVertically = true;   
  		this.createLevel();
          game.input.onDown.add(this.pickTile, this);
  	}, 
	createLevel: function(){
          this.tilesArray = [];
          this.arrowsArray = [];
          // group creation and placement to stay in the center of the canvas
		this.tileGroup = game.add.group();
          this.arrowsGroup = game.add.group();
          var groupSize = gameOptions.tileSize * gameOptions.fieldSize;
          this.tileGroup.x = (game.width - groupSize) / 2;
          this.tileGroup.y = (game.height - groupSize) / 2;
          this.arrowsGroup.x = (game.width - groupSize) / 2;
          this.arrowsGroup.y = (game.height - groupSize) / 2;
          // tile creation
  		for(var i = 0; i < gameOptions.fieldSize; i++){
               this.tilesArray[i] = [];
			for(var j = 0; j < gameOptions.fieldSize; j++){
				this.addTile(i, j);
			}
		}
	},
	addTile: function(row, col){
          // adding a new tile
		var tileXPos = col * gameOptions.tileSize + gameOptions.tileSize / 2;
		var tileYPos = row * gameOptions.tileSize + gameOptions.tileSize / 2;
		var theTile = game.add.sprite(tileXPos, tileYPos, "tiles");
		theTile.anchor.set(0.5);
          theTile.picked = false;
          theTile.coordinate = new Phaser.Point(col, row);
          this.tilesArray[row][col] = theTile;
	     this.tileGroup.add(theTile);	
	},
     pickTile: function(e){
          // picking the first tile
          this.visitedTiles = [];
          this.visitedTiles.length = 0;
          if(this.tileGroup.getBounds().contains(e.position.x, e.position.y)){
               var col = Math.floor((e.position.x - this.tileGroup.x) / gameOptions.tileSize);
               var row = Math.floor((e.position.y - this.tileGroup.y) / gameOptions.tileSize);
               this.tilesArray[row][col].alpha = 0.5;
               this.tilesArray[row][col].picked = true;
               game.input.onDown.remove(this.pickTile, this);
	     	game.input.onUp.add(this.releaseTile, this);
	     	game.input.addMoveCallback(this.moveTile, this);
               this.visitedTiles.push(this.tilesArray[row][col].coordinate);
          }  
     },
     moveTile: function(e){
          // we are over a tile
          if(this.tileGroup.getBounds().contains(e.position.x, e.position.y)){
               var col = Math.floor((e.position.x - this.tileGroup.x) / gameOptions.tileSize);
               var row = Math.floor((e.position.y - this.tileGroup.y) / gameOptions.tileSize);
               var distance = new Phaser.Point(e.position.x - this.tileGroup.x, e.position.y - this.tileGroup.y).distance(this.tilesArray[row][col]);
               // we are inside enough a tile
               if(distance < gameOptions.tileSize * 0.4){
                    // a new, adjacent tile
                    if(!this.tilesArray[row][col].picked && this.checkAdjacent(new Phaser.Point(col, row), this.visitedTiles[this.visitedTiles.length - 1])){
                         this.tilesArray[row][col].picked = true;
                         this.tilesArray[row][col].alpha = 0.5;
                         this.visitedTiles.push(this.tilesArray[row][col].coordinate);
                         this.addArrow();
                    }
                    // backtrack
                    else{
                         if(this.visitedTiles.length > 1 && row == this.visitedTiles[this.visitedTiles.length - 2].y && col == this.visitedTiles[this.visitedTiles.length - 2].x){
                              this.tilesArray[this.visitedTiles[this.visitedTiles.length - 1].y][this.visitedTiles[this.visitedTiles.length - 1].x].picked = false;
                              this.tilesArray[this.visitedTiles[this.visitedTiles.length - 1].y][this.visitedTiles[this.visitedTiles.length - 1].x].alpha = 1;
                              this.visitedTiles.pop();
                              this.arrowsArray[this.arrowsArray.length - 1].destroy();
                              this.arrowsArray.pop();
                         }
                    }
               }
          }
     },
     releaseTile: function(){
          // clear the path
          this.arrowsGroup.removeAll(true);
          for(var i = 0; i < gameOptions.fieldSize; i++){
			for(var j = 0; j < gameOptions.fieldSize; j++){
				this.tilesArray[i][j].alpha = 1;
                    this.tilesArray[i][j].picked = false;
			}
		}
          game.input.onUp.remove(this.releaseTile, this);
		game.input.deleteMoveCallback(this.moveTile, this);
          game.input.onDown.add(this.pickTile, this);     
     },
     checkAdjacent: function(p1, p2){
          return (Math.abs(p1.x - p2.x) <= 1) && (Math.abs(p1.y - p2.y) <= 1);
     },
     addArrow: function(){   
          // adding the arrows
          var fromTile = this.visitedTiles[this.visitedTiles.length - 2];
          var arrow = game.add.sprite(this.tilesArray[fromTile.y][fromTile.x].x, this.tilesArray[fromTile.y][fromTile.x].y, "arrows");
          this.arrowsGroup.add(arrow);
          arrow.anchor.set(0.5);
          // this routine handles arrow frame and angle according to its direction
          var tileDiff = new Phaser.Point(this.visitedTiles[this.visitedTiles.length - 1].x, this.visitedTiles[this.visitedTiles.length - 1].y)       
          tileDiff.subtract(this.visitedTiles[this.visitedTiles.length - 2].x, this.visitedTiles[this.visitedTiles.length - 2].y);          
          if(tileDiff.x == 0){
               arrow.angle = -90 * tileDiff.y;     
          }
          else{
               arrow.angle = 90 * (tileDiff.x + 1); 
               if(tileDiff.y != 0){
                    arrow.frame = 1;
                    if(tileDiff.y + tileDiff.x == 0){
                         arrow.angle -= 90;
                    }
               }   
          } 
          this.arrowsArray.push(arrow);        
     }
}