function loadImages(sources, callback) {
        var images = {};
        var loadedImages = 0;
        var numImages = 0;
        // get num of sources
        for(var src in sources) {
          numImages++;
        }
        for(var src in sources) {
          images[src] = new Image();
          images[src].onload = function() {
            if(++loadedImages >= numImages) {
              callback(images);
            }
          };
          images[src].src = sources[src];
        }
      }

    window.onload = function() {
        var canvas = document.getElementById("gameCanvas");
        ctx = canvas.getContext("2d");		
        var sources = {
          trees: "./images/trees/trees.png",
          seened: "./images/seened/seened.png",
		  koll: "images/hero_ani.png",
		  bug: "images/bug_32_ani.png"
        };
		loadImages(sources, initGame);
		}
//function initGame(images){ 
var initGame = function(images){
	d0 = 32; // module - width of a tree tile
	var k = 2; // how many tiles per side
	var n = 10; // how many squares in row/column on screen
	var vl = n; //number of columns in (virtual) labyrinth
	var rl = 20; //number of rows in (virtual) labyrinth
	d = k * d0; // width of one labyrinth square
	wc = n * d+d0; //canvas width
	hc = 480; //(n-1) * d+d0; //canvas height
	
	w0 = wc; //width of virtual canvas
	h0 = rl*d+d0;  //height of virtual canvas
	xb = d/2; //kolli (bogy) (alg)asend virtuaalses labyrindis
	yb = d/2;
	//xbc = xb; //bogy on screen
	//ybc = yb;
	xl = 0; //start position of labyrinth on screen
	yl = 0; //start position of labyrinth
	ctx.canvas.width = wc;
	ctx.canvas.height = hc;
	var canvas0 = document.createElement('canvas');
	ctx0 = canvas0.getContext('2d');
	//canvas0.id     = "VirtualCanvas";
	canvas0.width  = w0;
	canvas0.height = h0;
	pick_snd =  document.getElementById("pick");
	bug_snd =  document.getElementById("bug");
	ough_snd =  document.getElementById("ough");
	var trees = new spriteSheet(images.trees,[[0,0,32,32],[33,0,32,32],[0,33,32,32],[33,33,32,32]]);
	seened = new spriteSheet(images.seened,[[0,0,32,32],[33, 0, 32, 32],[66,0,32,32],[0, 33, 32, 32],[33, 33, 32, 32],[0, 66, 32, 32],[33, 66, 32, 32],[66, 33, 32, 32],[66, 66, 32, 32]]);
		
	koll = new animated(images.koll,d0,d0,2,"still",16);
	koll.width=30;
	koll.height=30;
	koll.blushing = false;
	koll_red = colorize(images.koll,d0,d0,255,0,0,0.2);
			
	nbugs = 3;
	bugs=[];
	nseeni = 40; //kui palju lisatakse mängu (peab olema < v*r-1 - esimene ruut kolli jaoks!)
	nseeni = Math.min(vl*rl-1,nseeni);
	seenekohad = []; //ruudud, kus seened paiknevad
	korjatud = 0;
	//var objs=[];  //kõik seinad
	keysDown = [];
	keysDown[37]=keysDown[38]=keysDown[39]=keysDown[40]=false;
	speed = 2;
	
	create(vl,rl,n,d0,d,trees,w0,h0);
	inf = document.getElementById('inf');
	placeseened(vl,rl,d,seened.coords.length);
	createseened();
	createbugs(images.bug,nbugs,n,d0,d);
	window.addEventListener("keydown", function (e) {
	//if(e.keyCode>=37 && e.keyCode<=40){
		keysDown[e.keyCode] = true;
		
	//	}
	/*
	if (e.keyCode == 74)
		korja();
	*/
	}, false);

	window.addEventListener("keyup", function (e) {
	//if(e.keyCode>=37 && e.keyCode<=40){
		keysDown[e.keyCode] = false;
		
		//}
	}, false);
	/*
	window.addEventListener("click", function (e) {
	GameLoop();
	},false);
	*/
	koll.setPosition(xb,yb);
	
	GameLoop();
}
	
	function GameLoop(){
		update(speed);
		/*
		if (koll.x+xl > wc/2+d && wc - xl < w0)
			{xl -= speed;
			}
		else if (koll.x+xl < wc/2 && xl > 0)
			{xl += speed;
			}
		*/
		if (koll.y+yl > hc/2 &&  hc - yl < h0)
			{yl -= speed; }
		else if (koll.y+yl < hc/2-d && yl <0)
			{yl += speed;}
		//ctx.clearRect(0,0,wc,hc);

		ctx.putImageData(seenemets, 0,yl,0, -yl,wc,hc);
		if (!koll.blushing)
			koll.draw();
		else
			ctx.putImageData(koll_red,koll.x+xl,koll.y+yl);
		for(var i=0;i<nbugs;i++){
		bugs[i].move();}
		//ctx.putImageData(koll_red,koll.x+xl,koll.y+yl+d0);
		if (collision (xb,yb,32,32,w0-32,h0-64,32,32)){
			inf.innerHTML = 'Väljas! Korjasid on '+korjatud+' seent, seeni jäi metsa '+(nseeni-korjatud)+'!'
			setTimeout(redirect,2000);
			}
		else		
			setTimeout(GameLoop, 30);
	}
function redirect(){
	window.location="http://deepthought.ttu.ee/infoinst/conference/courswre/games/";}
    
function update(sp){

	var dx = 0;
	var dy = 0;
	
	if (keysDown[37]) { // left arrow
		dx = -sp;
	}
	if (keysDown[38]) { // up arrow
		dy = -sp;
	}
	if (keysDown[39]) { // right arrow
		dx = sp;
	}
	if (keysDown[40]) { // down arrow
		dy = sp;
	}
	/*
	if (keysDown[66]) // 'b'
		bug.move();
*/		
	//console.log('upd dx,dy :'+dx+','+dy);
	if(dx !=0 || dy !=0) {
		koll.state = "walking";
		check_collision(dx,dy,koll,labyr);
		}
	else
		koll.state = "still";
};
	
function check_collision(dx,dy,obj1,obj2){ //obj1 is moving, obj2 is bitmapdata to check
	
	var x = obj1.x;
	var y = obj1.y;
	var wb = obj1.width;		
	var hb = obj1.height;
	
	var points1;
	
	if (dx < 0) {
		if (dy == 0)
			points1 = [[x,y],[x,y+hb]]; 
		else if (dy > 0)
			points1 = [[x,y],[x,y+hb],[x+wb,y+hb]]; 
		else if (dy < 0)
			points1 = [[x+wb,y],[x,y],[x,y+hb]]; 
			};
	if (dx == 0) {
		if (dy > 0)
			points1 = [[x,y+hb],[x+wb,y+hb]]; 
		else if (dy < 0)
			points1 = [[x+wb,y],[x,y]];
			};
	if (dx > 0) {
		if (dy == 0)
			points1 = [[x+wb,y+hb],[x+wb,y]]; 
		else if (dy > 0)
			points1 = [[x,y+hb],[x+wb,y+hb],[x+wb,y]]; 
		else if (dy < 0)
			points1 = [[x+wb,y+hb],[x+wb,y],[x,y]]; 
			};
			 
	 var t = 0;
	 var j = Math.max(Math.abs(dx),Math.abs(dy)); //how many steps to check
	 var ddx = dx/j;
	 var ddy = dy/j;
	 found: do{
		t++;
		var i = 0;
	  do{
		 var x1 = points1[i][0]; //coordinate of the faremost corner
		 var y1 = points1[i][1];
		 //console.log('x,dx,x1,y,dy,y1 :'+x+','+dx+','+x1+'; '+y+','+dy+','+y1);
		 var xx1 = (x1+t*ddx);
		 var yy1 = (y1+t*ddy);
		 var p = 4*(xx1 + w0*yy1);
		 if (obj2.data[p+3]!=0 ) // not transparent!
		 { //console.log('i,t,xx1,yy1,p,obj2.data[p+3]: '+i+','+t+','+xx1+','+yy1+','+p+','+obj2.data[p+3])
		 break found; }; 
		 i++; 
		 } while (i < points1.length); 
		} while (t<j) ;
	
	xb = Math.floor(xb + (t-1)*ddx); //move obj1 !
	yb = Math.floor(yb + (t-1)*ddy);
	koll.setPosition(xb,yb);
	korja();
}
function korja(){
// kontrollime ruudu [xb,yb,32,32] lõikumist 
// ruuduga [seenekohad[i].x, seenekohad[i].y, 32,32]

	var i = 0;
	while (i < seenekohad.length){
		if 	(collision(xb,yb,32,32,seenekohad[i].x,seenekohad[i].y,32,32)) 
			break;
		else
			i++;}
	
	if (i < seenekohad.length) //oli seen!
	{	if (keysDown[75]) { 	// 75 = "k"
			if (seenekohad[i].seen == 0) {
				inf.innerHTML = 'Korjasid mürgise kärbseseene!';
				ctx.globalAlpha = 0.2;
				ough_snd.cloneNode(true).play();
				setTimeout(restore,200);
				}
			else {
				korjatud ++;
				pick_snd.cloneNode(true).play();
				inf.innerHTML = 'Korjatud '+korjatud + ' seent!';
				seenekohad.splice(i,1);
				createseened(); //uued!
				}
			}
		else  
			{//show that player did not collect
			//console.log('seen korjamata!');
			}
			
	}			
}
function restore(){
	ctx.globalAlpha = 1;
	}
function collision(x1,y1,w1,h1,x2,y2,w2,h2){
	return 	x1 < x2 + w2 && x2 < x1 + w1 &&
			y1 < y2 + h2 && y2 < y1 + h1
	}

function placeseened(v,r,d,n){
	//select random squares for mushrooms
	var indexis=[];
	var seenekohad1 = []; //ajutine massiiv otsimiseks
	for(var i = 0; i < v*r-1; i++) indexis[i] = i+1; //ruudud alates teisest - esimeses on 
	var i0 = Math.floor(Math.random()*indexis.length);
	seenekohad1.push(indexis[i0]);
	indexis.splice(i0,1);
	i0 = Math.floor(Math.random()*indexis.length); //next!
	while(seenekohad1.length < nseeni && seenekohad1.indexOf(indexis[i0])==-1){
	seenekohad1.push(indexis[i0]);
	indexis.splice(i0,1);
	i0 = Math.floor(Math.random()*indexis.length);
	}
	//console.log(seenekohad);
	for (var i = 0; i < nseeni; i++) {
	var v1 = seenekohad1[i]%v;
	var r1 = Math.floor(seenekohad1[i]/v);
	var sx = v1*d + d/2;
	var sy = r1*d + d/2;
	seenekohad.push({r:indexis[i0],x:sx,y:sy, seen:Math.floor(Math.random()*n)});
	}
	return seenekohad;
}

function createseened() {
	ctx0.clearRect(0,0,w0,h0);
	ctx0.putImageData(labyr, 0,0);
	for(var i=0;i < seenekohad.length; i++) {
	seened.draw0(seenekohad[i].seen,seenekohad[i].x, seenekohad[i].y );
	}
	seenemets = ctx0.getImageData(0, 0, w0, h0);
	//objs.push({x:seened[seenekohad[i].x,y:seened[seenekohad[i].y,type:'seen'+i.toString});
}

function createbugs(img,nbugs,n,d0,d){
	
	for (i=0;i<nbugs;i++){
	bug = new animated(img,d0,d0,2,"moving",12);
	bug.vx = 0;
	bug.vy = 0;
	bug.move = function(){
	if (this.x%d == 0 && this.y%d == 0) // on crossroad
		{
		var p = 4*(this.x+d0/2 + w0*(this.y+d0/2)); //puugi keskkoht
		if (Math.abs(koll.x-this.x)>Math.abs(koll.y-this.y) && Math.random()>0.6){
			if ((koll.x-this.x)>0 && labyr.data[p+4*d0 + 3] > 0) 
				{this.vx = 1; this.vy = 0}
			else if ((xb-this.x)<0 && labyr.data[p-4*d0 + 3] > 0) 
				{this.vx = -1; this.vy = 0} }
		else  {
			if ((yb-this.y)>0 && labyr.data[p+4*d0*w0 + 3] > 0) 
				{this.vx = 0; this.vy = 1}
			else if ((yb-this.y)<0 && labyr.data[p-4*d0*w0 + 3] > 0) 
				{this.vx = 0; this.vy = -1} 
			else
				{this.vx *= -1; this.vy *= -1; }} //go back
		}
		this.x += this.vx;
		this.y += this.vy;
		this.draw();
		if (collision(this.x-d0,this.y-d0,3*d0,3*d0,koll.x,koll.y,d0,d0)) {
			bug_snd.cloneNode(true).play();
			koll.blushing = true;
			inf.innerHTML = "Sinu küljes on puuk!";
			setTimeout(koll_normal,500);}
	
	}
	do{
	var bx = (2+Math.floor(Math.random()*(n-2)))*d; //bug on screen
	var by = (2+Math.floor(Math.random()*(Math.floor(hc/d-2))))*d; //hc asemele hv !!!
	var p =  4*(bx+d0/2 + w0*(by+d0/2));
		} while (labyr.data[p+3]==0);
	bug.setPosition(bx,by);
	bugs[i]=bug;
	}
	return bugs;
	}

function koll_normal(){
	koll.blushing = false;
	inf.innerHTML = "Pääsesid!";
	}	
	
function spriteSheet(img,coords){
	this.coords = coords;
	//coords = [[x0,y0,w0,h0],...[xn,yn,wn,hn]]
	this.sheet = img;
	this.draw = function(nr,x,y){
		ctx.drawImage(img,this.coords[nr][0],this.coords[nr][1],this.coords[nr][2],this.coords[nr][3],x,y,this.coords[nr][2],this.coords[nr][3]);
	}
	this.draw0 = function(nr,x,y){
		ctx0.drawImage(img,this.coords[nr][0],this.coords[nr][1],this.coords[nr][2],this.coords[nr][3],x,y,this.coords[nr][2],this.coords[nr][3]);
	}
}
	
function animated(img,dx,dy,n_fr,state,sp){
	  this.image = img;
	  //console.log('koll: '+this.image.height);
	  this.width = dx;
	  this.height = dy;
	  this.dx = dx; //this.width;
	  this.dy = dy; //this.height/3; //32
	  this.n_frames = n_fr; //number of frames
	  this.actualFrame = 0;
	  this.speed = sp;  //how many *game* frames a frame is shown
	  this.step = 0;
	  this.y = 0;
	  this.x = 0; 
	  this.state = state;		  
	  
	  this.setPosition = function(X, Y){
		this.x = X;
		this.y = Y;
	  }

	  this.draw = function(cx,cy){
	  var cx=cx||0;
	  var cy=cy||0;
	  if (this.state == "still")
		ctx.drawImage(this.image,0,this.dy*2,this.dx,this.dy,this.x,this.y+yl,this.dx,this.dy);
		else {   //state == "walking"
		ctx.drawImage(this.image,0,this.dy*this.actualFrame,this.dx,this.dy,this.x,this.y+yl,this.dx,this.dy);
		this.step ++;
		if (this.step == this.speed) {
			this.actualFrame++;
			this.actualFrame = this.actualFrame%this.n_frames
			this.step = 0;
			}
			}
		}
	}
	
function create(vl,rl,n,d0,d,trees,w0,h0){
	var ruudud = [];
	var connected = [];
	var free = [];
	var dirs = [0, 1, 2, 3];
	for (i = 0; i < rl; i++) {
			for (var j = 0; j < vl; j++) {
				ruudud.push(new ruut(i, j));
			}
		}
	var i0 = random(0,ruudud.length);
	connected.push(ruudud[i0]);
	//esimene ruum labyrindis
	free = ruudud.slice(0);
	//console.log("free: "+free.length);
	free.splice(i0, 1);
	//Next line starts Firebug debugger!
	//debugger;
	while (free.length > 0) {
		var found = 0;
		while (found == 0) {
			i0 = random(0, connected.length);
			var r = connected[i0];
			//kandidaat!
			var dirs = [0, 1, 2, 3];
			for (i = 0; i < 4; i++) {
				if (r.doors.indexOf(dirs[i]) > 0)
					dirs.splice(i, 1);
			}
			while (dirs.length > 0) {
				var j0 = random(0, dirs.length);
				var d1 = dirs[j0];
				var i1 = next(r, d1,free);
				if (i1 >= 0) {
					var r1 = free[i1];
					found = 1;
					r.doors.push(d1);
					var d2 = reverse(d1);
					r1.doors.push(d2);
					connected.push(r1);
					free.splice(i1, 1);
					break;
				} else {
					dirs.splice(j0, 1);
				}
			}
		}
	}
	//draw labyrinth
	for (var i = 0; i < connected.length; i++) {
		var xx = connected[i].m;
		var yy = connected[i].n;
		if (connected[i].doors.indexOf(0) == -1)
			treeline((xx + 1) * d, yy * d, (xx + 1) * d, (yy + 1) * d, d0, trees);
		if (connected[i].doors.indexOf(1) == -1)
			treeline(xx * d, (yy + 1) * d, (xx + 1) * d+1, (yy + 1) * d, d0, trees);
		//if (connected[i].doors.indexOf(0) == -1 && connected[i].doors.indexOf(1) == -1)
		//	ctx.drawImage(tile, (xx + 2) * d, (yy + 2) * d);
		if (xx == 0 && connected[i].doors.indexOf(2) == -1)
			treeline(xx * d, yy * d, xx * d, (yy + 1) * d, d0, trees);
		if (yy == 0 && connected[i].doors.indexOf(3) == -1)
			treeline(xx * d, yy * d, (xx + 1) * d, yy * d, d0, trees);
		ctx0.clearRect(w0-d0,h0-2*d0,d0,d0); // door out!
			
	}
	labyr = ctx0.getImageData(0, 0, w0, h0);
}

function next(r, dir,free) {
	var nn1;
	var mm1;
	switch (dir) {
		case 0:
			nn1 = r.n;
			mm1 = r.m + 1;
			break;
		case 1:
			nn1 = r.n + 1;
			mm1 = r.m;
			break;
		case 2:
			nn1 = r.n;
			mm1 = r.m - 1;
			break;
		case 3:
			nn1 = r.n - 1;
			mm1 = r.m;
			break;
		default:
			nn1 = r.n;
			mm1 = r.m;
	}
	
	for (var i = 0; i < free.length; i++) {
		//console.log(i+' '+n1+' '+m1);
		if ((free[i].n == nn1) && (free[i].m == mm1)) {
			return i;
			break;
		}
	}
	return -1;
}

function connection(n, m, direction) {
	//direction=1 - right
	//direction=2 - down
	//direction=3 - left
	//direction=4 - up
	switch (direction) {
		case 0:
			this.n1 = n;
			this.m1 = m;
			this.n2 = n + 1;
			this.m2 = m;
			this.dir = 0;
			break;
		case 1:
			this.n1 = n;
			this.m1 = m;
			this.n2 = n;
			this.m2 = m + 1;
			this.dir = 1;
			break;
		case 2:
			this.n1 = n;
			this.m1 = m;
			this.n2 = n - 1;
			this.m2 = m;
			this.dir = 2;
			break;
		case 3:
			this.n1 = n;
			this.m1 = m;
			this.n2 = n;
			this.m2 = m - 1;
			this.dir = 3;
			break;
		default:
			this.n1 = n;
			this.m1 = m;
			this.n2 = n;
			this.m2 = m;
			this.dir = 0;
		//no connection
	}
}

function reverse(dir) {
	return (dir + 2) % 4;
}
function ruut(n, m) {
	this.n = n;
	this.m = m;
	this.doors = [];
	}
	
function treeline(x0,y0,x1,y1,d0, trees){
	var nx = (x1 - x0)/d0;
	var ny = (y1 - y0)/d0;
	var n = Math.max(nx,ny);
	var dx = (x1 - x0)/n;
	var dy = (y1 - y0)/n;
	for(var i=0;i < n;i++){
		trees.draw0(Math.floor(Math.random()*trees.coords.length),x0 + i*dx, y0 + i*dy);
		//ctx0.drawImage(tile, x0 + i*dx, y0 + i*dy);
		//objs.push({x:x0 + i*dx,y:y0 + i*dy,type:'tile'});
	}
}
function colorize(img,w,h,r,g,b,a){
ctx0.clearRect(0,0,w,h);
ctx0.drawImage(img,0,0);
var im_data=ctx0.getImageData(0,0,w,h);
for(var i=0;i<im_data.length/4;i+=4){
	im_data.data[i] = 255 - data[i]; //r; //Math.max(im_data.data[i],r);
	im_data.data[i+1] = 255 - data[i]; //g; //Math.max(im_data.data[i],g);
	im_data.data[i+2] = 255 - data[i]; //b; //Math.max(im_data.data[i],b);
	im_data.data[i+3] = im_data.data[i+3]*a;
	}
ctx0.clearRect(0,0,img.width,img.height);
return im_data;
}

function random(min, max) {
	return Math.floor(Math.random() * (max - min )) + min;
}