//WINDOW-SNAKE
//2005 Sylvain Vriens
//(C) PROJECT-EUH.COM

function hasPopupBocker(){ //return TRUE if pop-up blocker detected
	test = window.open("", "test","width=1,height=1,scrollbars=no,left=5000,top=5000");
	if(test==null || typeof(test)=="undefined" || test.closed==true){
		return true;
	}
	try{
    	test.close();
    }catch(vEx){
    	return true;
    }
	return false;
}

function startGame(){ //init the game
	//test for pop-up blockers
	if(hasPopupBocker()){
		return;
	}
	
	//clear all thing from previous game
	clearTimers();
	closeAllWindows();


	//init game variables
	partsCount = 0;
	direction = 1;
	maxLength = 15;
	updateTime = 300;
	minTime = 50;
	score = 0;
	candyHit = false;
	windowError = false;
	snake = new Array();
	positions = new Array();
	
	
	//window sizes
	partW = 100;
	partH = 100;
	
	itemW = 100;
	itemH = 100;


	//change my background
	changeBGImage("img/snakeback_blurred.jpg");
	
	
	//set up grid
	screenW = window.screen.availWidth;
	screenH = window.screen.availHeight;
	
	gridW = Math.floor(screenW/partW);
	gridH = Math.floor(screenH/partH);
	
	gridOffX = (screenW-gridW*partW)/2;
	gridOffY = (screenH-gridH*partH)/2;
	
	
	//set score and windows
	setScore(score);
	
	placeCandy();
	
	addPart();
	addPart();
	addPart();
	moveToPosition(0);
	moveToPosition(1);
	moveToPosition(2);

	placeCandy();
	

	//first call to update positions
	//starts the game
	updatePositions();
	
	//playSound!!
	//playMusic();
	//fadeUp(100);
	
}

function gameOver(){ //in case of losers!
	//change my background and images of windows
	changeBGImage("img/snakeback.jpg");
	for(x=0;x<partsCount;x++){
		try{
			snake[x].changeImage(0, "img/dead.gif");
			snake[x].changeBGImage("img/snakeback_blurred.jpg");
		}catch(vErr){}
	}
	try{
		candy.close();
	}catch(vErr){};

	//start the timer to close all windows
	closeTimer = window.setTimeout("closeAllWindows()",5000);
	//stopMusic();
	//fadeDown(25);
	gameOverSound();
}

function addPart(){ //adds a part to the snake

	//check if allowed to add
	if(partsCount<=maxLength){
		if(typeof(snake[partsCount])=="undefined"){
			snake[partsCount] = window.open("snakepart.html", "snake" + partsCount,"toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width="+partW+",height="+partH);
		}
		
		//add position to list
		positions[partsCount] = new Array(0,1);

		partsCount = partsCount + 1;
	}
	
}

function removePart(){
	partsCount = partsCount - 1;
	try{
		snake[partsCount].close();
	}catch(vErr){}
}

function placeCandy(){
	//check if candy already opened and if not, open it!
	try{
		if(typeof(candy)!="object" || candy.closed){
			candy = window.open("candy.html", "candy","status=0,toolbar=0,width="+itemW+",height="+itemH);
		}
	}catch(vErr){
		candy = window.open("candy.html", "candy","status=0,toolbar=0,width="+itemW+",height="+itemH);
	}
	//create new position	
	candyPos = new Array(2);
	
	//return handle
	search_loop:
	//find a free space to place candy
	while(true){
		vX = Math.round(Math.random()*gridW+0.5)-1;
		vY = Math.round(Math.random()*gridH+0.5)-1;
		for(x=0;x<partsCount;x++){
			if(vX == positions[x][0] && vY == positions[x][1]){
				//overlap, continue at return handle
				continue search_loop;
			}
		}
		//position found, exit loop
		break;
	}
	
	candyPos[0] = vX;
	candyPos[1] = vY;
	vPos = gridLocToPos(candyPos);
	
	//move candy to position
	try{
		candy.moveTo(vPos[0],vPos[1]);
		candy.focus();
	}catch(vErr){
		handleWindowError();
		return;
	}
	
}

function closeAllWindows(){//closes aal windeos
	try{
		for(x=0;x<partsCount;x++){
			try{
				snake[x].close();
				snake[x] = null;
			}catch(vErr){}
		}
		try{
			candy.close();
			candy = null;
		}catch(vErr){}
	}catch(vErr){}
}

function buttonPressed(vButton){//catches key presses from snakeparts
	switch(vButton){
		case 37: //left
			direction = 3;
			break;
		case 38: //up
			direction = 0;
			break;
		case 39: //right
			direction = 1;
			break;
		case 40: //down
			direction = 2;
			break;
	}
}

function hitCandy(){ //the snake got the prize!
	//place candy and add a part if allowed
	placeCandy();
	addPart();
		
	//change score
	score = score+1;
	setScore(score);
	
	//update speed every 2 points
	if(score%2==0){
		updateTime = updateTime - 25;
		updateTime = Math.max(updateTime, minTime);
	}
	
	//reset candy variable
	candyHit = false;
	

}

function updatePositions(){
	//if hit candy last step, do it now.
	if(candyHit){
		hitCandy();
	}

	//new headposition
	vPos = new Array(0,0);
	vPos[0] = positions[0][0] + (direction%2) * (direction-2) * -1;
	vPos[1] = positions[0][1] + (direction%2-1) * (direction-1) * -1;
	positions.pop();
	positions.unshift(vPos);

	if(windowError){
		//if window error detected don't do nothing ;)
	}else if(checkCollision()==false){
		//if no collision
		//move last snakepart in list to 1st position
		//only have to move 1 window this way
		vWin = snake.pop();
		snake.unshift(vWin);
		moveToPosition(0);
		
		if(!windowError){
			//do it again in a while
			timer = window.setTimeout("updatePositions()",updateTime);
		}
		
		moveSound();
		
	}else{
		//LOSER!
		gameOver();
	}
}

function moveToPosition(vID){ //move snakepart vID to it's position
	
	try{
		vPos = gridLocToPos(positions[vID]);
		snake[vID].moveTo(vPos[0], vPos[1]);
		snake[vID].focus();
	}catch(vEx){
		handleWindowError();
		return;
	}
	
}

function checkCollision(){ //checks for collision
	
	//check if outide screen...
	if(positions[0][0]<0 || positions[0][0]>=gridW){
		return true;
	}
	if(positions[0][1]<0 || positions[0][1]>=gridH){
		return true;
	}
	
	//is the snake biting itself?
	for(x=1;x<partsCount;x++){
		if(positions[0][0]==positions[x][0] && positions[0][1]==positions[x][1]){
				return true;
		}
	}
	
	//is the snake eating candy
	if(positions[0][0]==candyPos[0] && positions[0][1]==candyPos[1]){
		//just set a flag, loading a new window here would render making a turn impossible !
		candySound();
		candyHit = true;
	}

	
	return false;
}

function gridLocToPos(vPos){ //grid position to x,y coordinate of screen
	vReturn = new Array(2);
	vReturn[0] = gridOffX + vPos[0]*partW;
	vReturn[1] = gridOffY + vPos[1]*partH;
	return vReturn;
}

function clearTimers(){ //clear all running timers
	try{
		window.clearTimeout(closeTimer);
	}catch(vErr){}
	try{
		window.clearTimeout(timer);
	}catch(vErr){}
}

function handleWindowError(){ //alert on windowError
	if(!windowError){
		windowError = true;
		clearTimers();
		changeBGImage("img/snakeback.jpg");
		closeAllWindows();
		window.focus();
		alert("An error occurred.\n\nA pop-up blocker may still be active or a window may have been closed.");
	}
}

//safari only with debug menu turned on!
//terminal commando: defaults write com.apple.Safari IncludeDebugMenu 1
function printToConsole(vStr){
	if(window.console) {
		window.console.log(vStr);
	} 
}