Emanuele Feronato

// the game itself
var game;

// global game options
var gameOptions = {

     // width of the game, in pixels
     gameWidth: 600,
     
     // height of the game, in pixels
     gameHeight: 600,

     // size of the sprite sheet, in pixels
     spritesheetSize: 50, 
     
     // size of each tile, in pixels
     tileSize: 50,
     
     // size of the field, in tiles
     fieldSize: 6,
     
     // different tile types
     tileTypes: 6,
     
     // distance from the left of the screen to the left of the board, in pixels 
     offsetX: 150,
     
     // distance from the top of the screen to the top of the board, in pixels 
     offsetY: 150
}

// some constants to be used in the game

// I am not dragging
var NO_DRAG = 0;

// I am dragging horizontally
var HORIZONTAL_DRAG = 1;

// I am dragging vertically
var VERTICAL_DRAG = 2;

// The game state is "doing nothing"
var GAME_STATE_IDLE = 0;

// When the player is dragging a row/column
var GAME_STATE_DRAG = 1;

// When the player stops dragging
var GAME_STATE_STOP = 2;

// when the window has been fully loaded
window.onload = function() {	        

     // creation of a Game instance
	game = new Phaser.Game(600, 600);
     
     // adding "PlayGame" state
	game.state.add("PlayGame", playGame)
     
     // starting "PlayGame" state
	game.state.start("PlayGame");
}

var playGame = function(game){}
playGame.prototype = {

     // when the state preloads
	preload: function(){
     
          // loading the spritesheet with all tile images
          game.load.spritesheet("tiles", "tiles.png", gameOptions.spritesheetSize, gameOptions.spritesheetSize);
          
          // setting the game on maximum scale mode to cover the entire screen
          game.scale.scaleMode = Phaser.ScaleManager.SHOW_ALL;
          game.scale.pageAlignHorizontally = true;
          game.scale.pageAlignVertically = true; 
	},
     
      // once the state has been created
	create: function(){
     
          // tileArray is the array which will contain all tiles
          this.tileArray = [];
          
          // creation of the group which will contain all tiles
          this.tileGroup = game.add.group();
          
          // adjusting group position according to offset
          this.tileGroup.x = gameOptions.offsetX;
          this.tileGroup.y = gameOptions.offsetY;
          
          // creation of a mask with the same size of the board to be placed in the same position of the group
          // this way we are hiding everything is outside the board  
          this.tileMask = game.add.graphics(this.tileGroup.x, this.tileGroup.y);
          this.tileMask.beginFill(0xffffff);
          this.tileMask.drawRect(0, 0, gameOptions.fieldSize * gameOptions.tileSize, gameOptions.fieldSize * gameOptions.tileSize);
          this.tileGroup.mask = this.tileMask;
          this.tileMask.visible = true;
          
          // filling the board with tiles thanks to "addTile" method
          for(var i = 0; i < gameOptions.fieldSize; i++){
			this.tileArray[i] = [];
			for(j = 0; j < gameOptions.fieldSize; j++){
				this.addTile(i, j);
			}
		}
          
          // adding the temporary tile thanks to addTempTile method
		this.addTempTile();
          
          // waiting for player input to call pickTile method
		game.input.onDown.add(this.pickTile, this);
          
          // the game has just been created, so we are doing nothing
          this.gameState = GAME_STATE_IDLE;
	},
     
     // function to add a tile at a given row and column
     addTile: function(row, col){
     
          // choosing a random tile
          var randomTile = game.rnd.integerInRange(0, gameOptions.tileTypes - 1);
          
          // creation of the sprite in the proper position
		var theTile = game.add.sprite(col * gameOptions.tileSize, row * gameOptions.tileSize, "tiles");
		
          // setting tile width and height
          theTile.width = gameOptions.tileSize;
          theTile.height = gameOptions.tileSize;
          
          // showing the frame according to tile value
          theTile.frame = randomTile;
          
          // saving the value inside a custom property
		theTile.value = randomTile;
          
          // inserting the tile in tileArray array
		this.tileArray[row][col] = theTile;
          
          // adding the sprite to tileGroup group
          this.tileGroup.add(theTile);	
     },
     
     // function to add the temporary tile
     addTempTile: function(){
     
          // creation of the sprite, no matter the position, we won't show it at the moment
          this.tempTile = game.add.sprite(0, 0, "tiles");
          
          // setting its width and height
          this.tempTile.width = gameOptions.tileSize;
          this.tempTile.height = gameOptions.tileSize;
          
          // setting the sprite to non visible
		this.tempTile.visible = false;
          
          // adding the sprite to tileGroup group
          this.tileGroup.add(this.tempTile);	        
     },
     
     // function to triggered when the player touches/clicks on the canvas
     pickTile: function(e){
          
          // determining row and column according to input position, tile size and offset
          this.movingRow = Math.floor((e.position.y - gameOptions.offsetY) / gameOptions.tileSize);
          this.movingCol = Math.floor((e.position.x - gameOptions.offsetX) / gameOptions.tileSize);
          
          // if row and column are actually inside game field...
          if(this.movingRow >= 0 && this.movingCol >= 0 && this.movingRow < gameOptions.fieldSize && this.movingCol < gameOptions.fieldSize){
               
               // at the moment we aren't dragging
               this.dragDirection = NO_DRAG;
               
               // removing the listener which waits for the input to begin
               game.input.onDown.remove(this.pickTile, this);
               
               // adding a listener which waits for the input to end then call releaseTile method
               game.input.onUp.add(this.releaseTile, this);
               
               // adding a listener which waits for the input to move then call moveTile method
               game.input.addMoveCallback(this.moveTile, this);
          }
     },
     
     // function to be executed at each frame
     update:function(){
     
          // checking game state to see what to do
          switch(this.gameState){
          
               // we are dragging
               case GAME_STATE_DRAG:
               
                    // call handleDrag method
                    this.handleDrag();
               break;
               
               // we just stopped dragging
               case GAME_STATE_STOP:
               
                    // call handleStop method
                    this.handleStop();
               break;
          }
          
          // at the end of the function, we set gameState again to idle
          this.gameState = GAME_STATE_IDLE;     
     
          
     },
     
     // function to handle - and draw on the canvas - the game when the player drags a row/column
     handleDrag:function(){
          
          // two different things to do according to drag direction
          switch(this.dragDirection){
               
               // horizontal drag
               case HORIZONTAL_DRAG:
               
                    // hiding temporary tile
     			this.tempTile.visible = false;
                    
                    // placing the temporary tile in the proper row
     			this.tempTile.y = this.movingRow * gameOptions.tileSize;
                    
                    // deltaX is the amount of tiles we are moving
     			var deltaX = (Math.floor(this.distX / gameOptions.tileSize) % gameOptions.fieldSize);
                    
     			// deltaX >= 0 means we are moving to the right (or not moving)
                    if (deltaX >= 0) {		
                    
                         // temporary tile frame is now the same as the rightmost visible tile							
     				this.tempTile.frame = this.tileArray[this.movingRow][gameOptions.fieldSize - 1 - deltaX].value;
     			}
                    
                    // we are moving to the left
     			else{
                    
                         // temporary tile frame is now the same as the leftmost visible tile
     				deltaX = deltaX * -1 - 1;
     				this.tempTile.frame = this.tileArray[this.movingRow][deltaX].value;		
     			}
                    
                    // looping through all the moving row
     			for(var i = 0; i < gameOptions.fieldSize; i++){
                    
                         // adjusting each tile horizontal position
     				this.tileArray[this.movingRow][i].x = (i * gameOptions.tileSize + this.distX) % (gameOptions.tileSize * gameOptions.fieldSize);
     				
                         // if tile position is less than zero...
                         if (this.tileArray[this.movingRow][i].x < 0) {
                         
                              // ... place it on the opposite side of the game field
        					this.tileArray[this.movingRow][i].x += gameOptions.tileSize * gameOptions.fieldSize;
     				}
     			}
                    // tileX is the amount of pixels we are moving, capped to gameOptions.tileSize
                      var tileX = this.distX % gameOptions.tileSize;
                    
                    // if the amount is greater than zero (moving to the right)
                    if(tileX > 0){
                         
                         // placing temporary tile before the leftmost tile
                         this.tempTile.x = tileX - gameOptions.tileSize;
                         
                         // showing temportary tile
                    	this.tempTile.visible = true;
                    }
                    
                    // if the amount is less than zero (moving to the left)
                    if(tileX < 0){
                         
                         // placing temporary tile before the leftmost tile
                         this.tempTile.x = tileX;      
                         
                         // showing temportary tile
                    	this.tempTile.visible = true;
                    } 
     		break;
               
               // vertical drag, same concept seen in horizontal drag, just applied to Y axis
               case VERTICAL_DRAG:
     			this.tempTile.visible = false;
     			this.tempTile.x = this.movingCol * gameOptions.tileSize;
     			var deltaY = (Math.floor(this.distY / gameOptions.tileSize) % gameOptions.fieldSize);
     			if (deltaY >= 0) {									
     				this.tempTile.frame = this.tileArray[gameOptions.fieldSize - 1 - deltaY][this.movingCol].value;
     			}
     			else{
     				deltaY = deltaY * -1 - 1;
     				this.tempTile.frame = this.tileArray[deltaY][this.movingCol].value;		
     			}
     			for(var i = 0; i < gameOptions.fieldSize; i++){
     				this.tileArray[i][this.movingCol].y = (i * gameOptions.tileSize + this.distY) % (gameOptions.tileSize * gameOptions.fieldSize);
     				if (this.tileArray[i][this.movingCol].y < 0) {
        					this.tileArray[i][this.movingCol].y += gameOptions.tileSize * gameOptions.fieldSize;
     				}  
     			}
                    var tileY = this.distY % gameOptions.tileSize;
                    if(tileY > 0){
                         this.tempTile.y = tileY - gameOptions.tileSize;
                         this.tempTile.visible = true;
                    }
                    if(tileY < 0){
                         this.tempTile.y = tileY;      
                         this.tempTile.visible = true;
                    } 
     		break;     
          }
     },
     
     // function to handle - and draw on the canvas - the game when the player stops dragging a row/column
     handleStop:function(){
     
          // hiding temporary tile
          this.tempTile.visible = false;
     
          // two different things to do according to drag direction
          switch(this.dragDirection){
          
               // horizontal drag
     		case HORIZONTAL_DRAG:
               
                    // we have to find how many "half tiles" we dragged
     			var shiftAmount = Math.floor(this.distX / (gameOptions.tileSize / 2));
                    
                    // and now let's see how many tiles we dragged, with a modulo operation because the max amount is fieldSize - 1
     			shiftAmount = Math.ceil(shiftAmount / 2) % gameOptions.fieldSize;
                    
                    // creation of a temporary array
     			var tempArray = [];
                    
                    // now the idea is to insert in tempArray array the tileArray items in the order they are at the end of the drag
                    // when shiftAmount is greater than 0, we dragged to the right
     			if(shiftAmount > 0){
     				for(var i = 0; i < gameOptions.fieldSize; i++){
     					tempArray[(shiftAmount + i) % gameOptions.fieldSize] = this.tileArray[this.movingRow][i].value;
     				}
     			}
                    
                    // when shiftAmount is less than zero, we dragged to the left 
     			else{
     				shiftAmount *= -1;
     				for(var i = 0; i < gameOptions.fieldSize; i++){
     					tempArray[i] = this.tileArray[this.movingRow][(shiftAmount + i) % gameOptions.fieldSize].value;
     				}
     			}
                    
                    // copying content from tempArray to tileArray and adjust tile position
     			for(i = 0; i < gameOptions.fieldSize; i++){
     				this.tileArray[this.movingRow][i].value = tempArray[i];
     				this.tileArray[this.movingRow][i].frame = tempArray[i];
     				this.tileArray[this.movingRow][i].x = i * gameOptions.tileSize;
                    }
     		break;
               
               // vertical drag follows the same concepts seen in horizontal drag
     		case VERTICAL_DRAG:
     			var shiftAmount = Math.floor(this.distY / (gameOptions.tileSize / 2));
				shiftAmount = Math.ceil(shiftAmount / 2) % gameOptions.fieldSize;
				var tempArray = [];
				if(shiftAmount > 0){
					for(var i = 0; i < gameOptions.fieldSize; i++){
						tempArray[(shiftAmount + i) % gameOptions.fieldSize] = this.tileArray[i][this.movingCol].value;
					}
				}
				else{
					shiftAmount *= -1;
					for(var i = 0; i < gameOptions.fieldSize; i++){
						tempArray[i] = this.tileArray[(shiftAmount + i) % gameOptions.fieldSize][this.movingCol].value;
					}
				}
				for(var i = 0; i < gameOptions.fieldSize; i++){
					this.tileArray[i][this.movingCol].value = tempArray[i];
					this.tileArray[i][this.movingCol].frame = tempArray[i];
					this.tileArray[i][this.movingCol].y = i * gameOptions.tileSize;
                    }
     		break;	
     	}
          
          // we aren't dragging anymore
     	this.dragDirection = NO_DRAG;
     },
     
     // function to be triggered when the player moves the mouse/finger
     moveTile: function(e){
     
          // we are dragging
          this.gameState = GAME_STATE_DRAG;
     
          // determining horizontal and vertical distance between start and current input position
          this.distX = e.position.x - e.positionDown.x;
          this.distY = e.position.y - e.positionDown.y;
          
          // if we aren't dragging yet...
          if(this.dragDirection == NO_DRAG){
                         
               // how many pixels are we travelling with our finger/mouse?
     		var distance = e.position.distance(e.positionDown);
               
               // more than 5 pixels? ok, that's enough to determine the direction
     		if(distance > 5) {
               
                    // trigonometry to know drag angle
     			var dragAngle = Math.abs(Math.atan2(this.distY, this.distX));
                    
                    // if drag angle is between PI/4 and 3PI/4...
     			if((dragAngle > Math.PI / 4 && dragAngle < 3 * Math.PI / 4)) {
     				
                         // ... we can say it's a vertical drag
                         this.dragDirection = VERTICAL_DRAG;
     			}
     			else {
                    
                         // else it's an horizontal drag
     				this.dragDirection = HORIZONTAL_DRAG;
     			}
     		}
          }             
     },
     
     // function to be triggered when the player releases the mouse/finger
     releaseTile: function(){
     
          // we stopped dragging
          this.gameState = GAME_STATE_STOP;
          
          // updating listeners
          game.input.onDown.add(this.pickTile, this);
          game.input.onUp.remove(this.releaseTile, this);
          game.input.deleteMoveCallback(this.moveTile, this); 
     }
}