// Scroll to the bottom of an element
// $(jQuery).scrollBottom()
jQuery.fn.scrollBottom = function() {
	return jQuery(this).each(function() {
		jQuery(this).scrollTop(9999); // $(this).find(':last').offset().top
	})
};

// Like .serialize() but works on elements like inputs whether than forms
// $(jQuery).serializeArrayElem()
jQuery.fn.serializeArrayElem = function() {
	return jQuery(this).map(function(i, elem) {
		return { name: elem.name, value: jQuery(this).val() }
	})
}


// Fade out and show another element during `duration_in_seconds` seconds
// $(jQuery).replace_with_fade_with_duration('#elem', 10)
jQuery.fn.replace_with_fade_with_duration = function(replace, duration_in_seconds) {
	var $ = jQuery
	return $(this).map(function(i, elem) {
		$(elem).fadeOut('fast', function() {
			$(replace).fadeIn('slow', function() {
				setTimeout(function() {
					$(replace).fadeOut('fast', function() {
						$(elem).fadeIn('slow');
					});
				}, duration_in_seconds * 1000);
			});
		});
	});
	return true;
}

// Decay class, to call a callback less and less often. For example,
// make an Ajax request and freshen the decay only if the request has changed.
// 
// To start the timeouts, call decay_object.start()
// To freshen up the speed of query, call decay_object.reset()
// 
// Options:
//  - seconds: time between each callback at the start and after a reset() (default 2)
//  - decay: multiplier to use after each callback call (default 1.3)
//  - max: maximum number of seconds to wait between each call (default 42)
// 
// Example:
//   function decay_me() {
//     if (something() != "") this.reset();
//   }
//   new Decay(decay_me, { seconds: 2, decay: 1.3, max: 42 }).start()
function Decay(callback, options) {
	this.options = { seconds: 2, decay: 1.5, max: 30, callback: callback }
	$.extend(this.options, options);

	this.timer = this.options.seconds
	this.timeout = null
}
Decay.prototype = {
	// call this method to freshen up the speed of callbacks
	reset: function() {
		this.timer = this.options.seconds
		this.start()
	},

	// call this method to start the decay
	start: function() {
		clearTimeout(this.timeout)

		var that = this
		var call_loop = function() {
			that.options.callback.apply(that)
			that.start.apply(that) // recurse!
		}

		this.timeout = setTimeout(call_loop, this.timer * 1000)

		// calculate the next timer
		this.timer = this.timer * this.options.decay
		if (this.timer > this.options.max)
			this.timer = this.options.max
		return this
	}
}