// This THREEx helper makes it easy to handle the fullscreen API
// * it hides the prefix for each browser
// * it hides the little discrepencies of the various vendor API
// * at the time of this writing (nov 2011) it is available in 
//   [firefox nightly](http://blog.pearce.org.nz/2011/11/firefoxs-html-full-screen-api-enabled.html),
//   [webkit nightly](http://peter.sh/2011/01/javascript-full-screen-api-navigation-timing-and-repeating-css-gradients/) and
//   [chrome stable](http://updates.html5rocks.com/2011/10/Let-Your-Content-Do-the-Talking-Fullscreen-API).

// 
// # Code

//

/** @namespace */
var THREEx		= THREEx 		|| {};
THREEx.FullScreen	= THREEx.FullScreen	|| {};

/**
 * test if it is possible to have fullscreen
 * 
 * @returns {Boolean} true if fullscreen API is available, false otherwise
*/
THREEx.FullScreen.available	= function()
{
	return this._hasWebkitFullScreen || this._hasMozFullScreen;
}

/**
 * test if fullscreen is currently activated
 * 
 * @returns {Boolean} true if fullscreen is currently activated, false otherwise
*/
THREEx.FullScreen.activated	= function()
{
	if( this._hasWebkitFullScreen ){
		return document.webkitIsFullScreen;
	}else if( this._hasMozFullScreen ){
		return document.mozFullScreen;
	}else{
		console.assert(false);
	}
}

/**
 * Request fullscreen on a given element
 * @param {DomElement} element to make fullscreen. optional. default to document.body
*/
THREEx.FullScreen.request	= function(element)
{
	element	= element	|| document.body;
	if( this._hasWebkitFullScreen ){
		element.webkitRequestFullScreen(Element.ALLOW_KEYBOARD_INPUT);
	}else if( this._hasMozFullScreen ){
		element.mozRequestFullScreen();
	}else{
		console.assert(false);
	}
}

/**
 * Cancel fullscreen
*/
THREEx.FullScreen.cancel	= function()
{
	if( this._hasWebkitFullScreen ){
		document.webkitCancelFullScreen();
	}else if( this._hasMozFullScreen ){
		document.mozCancelFullScreen();
	}else{
		console.assert(false);
	}
}


// internal functions to know which fullscreen API implementation is available
THREEx.FullScreen._hasWebkitFullScreen	= 'webkitCancelFullScreen' in document	? true : false;	
THREEx.FullScreen._hasMozFullScreen	= 'mozCancelFullScreen' in document	? true : false;	

/**
 * Bind a key to renderer screenshot
*/
THREEx.FullScreen.bindKey	= function(opts){
	opts		= opts		|| {};
	var charCode	= opts.charCode	|| 'f'.charCodeAt(0);
	var dblclick	= opts.dblclick !== undefined ? opts.dblclick : false;
	var element	= opts.element

	var toggle	= function(){
		if( THREEx.FullScreen.activated() ){
			THREEx.FullScreen.cancel();
		}else{
			THREEx.FullScreen.request(element);
		}		
	}

	// callback to handle keypress
	var __bind	= function(fn, me){ return function(){ return fn.apply(me, arguments); }; };
	var onKeyPress	= __bind(function(event){
		// return now if the KeyPress isnt for the proper charCode
		if( event.which !== charCode )	return;
		// toggle fullscreen
		toggle();
	}, this);

	// listen to keypress
	// NOTE: for firefox it seems mandatory to listen to document directly
	document.addEventListener('keypress', onKeyPress, false);
	// listen to dblclick
	dblclick && document.addEventListener('dblclick', toggle, false);

	return {
		unbind	: function(){
			document.removeEventListener('keypress', onKeyPress, false);
			dblclick && document.removeEventListener('dblclick', toggle, false);
		}
	};
}