/*
---

script: Request.JSONP.js

name: Request.JSONP

description: Defines Request.JSONP, a class for cross domain javascript via script injection.

license: MIT-style license

authors:
  - Aaron Newton
  - Guillermo Rauch
  - Arian Stolwijk

requires:
  - Core/Element
  - Core/Request
  - MooTools.More

provides: [Request.JSONP]

...
*/

Request.JSONP = new Class({

	Implements: [Chain, Events, Options],

	options: {/*
		onRequest: function(src, scriptElement){},
		onComplete: function(data){},
		onSuccess: function(data){},
		onCancel: function(){},
		onTimeout: function(){},
		onError: function(){}, */
		onRequest: function(src){
			if (this.options.log && window.console && console.log){
				console.log('JSONP retrieving script with url:' + src);
			}
		},
		onError: function(src){
			if (this.options.log && window.console && console.warn){
				console.warn('JSONP '+ src +' will fail in Internet Explorer, which enforces a 2083 bytes length limit on URIs');
			}
		},
		url: '',
		callbackKey: 'callback',
		injectScript: document.head,
		data: '',
		link: 'ignore',
		timeout: 0,
		log: false
	},

	initialize: function(options){
		this.setOptions(options);
	},

	send: function(options){
		if (!Request.prototype.check.call(this, options)) return this;
		this.running = true;

		var type = typeOf(options);
		if (type == 'string' || type == 'element') options = {data: options};
		options = Object.merge(this.options, options || {});

		var data = options.data;
		switch (typeOf(data)){
			case 'element': data = document.id(data).toQueryString(); break;
			case 'object': case 'hash': data = Object.toQueryString(data);
		}

		var index = this.index = Request.JSONP.counter++,
			key = 'request_' + index;

		var src = options.url +
			(options.url.test('\\?') ? '&' :'?') +
			(options.callbackKey) +
			'=Request.JSONP.request_map.request_'+ index +
			(data ? '&' + data : '');

		if (src.length > 2083) this.fireEvent('error', src);

		Request.JSONP.request_map[key] = function(){
			delete Request.JSONP.request_map[key];
			this.success(arguments, index);
		}.bind(this);

		var script = this.getScript(src).inject(options.injectScript);
		this.fireEvent('request', [src, script]);

		if (options.timeout) this.timeout.delay(options.timeout, this);

		return this;
	},

	getScript: function(src){
		if (!this.script) this.script = new Element('script', {
			type: 'text/javascript',
			async: true,
			src: src
		});
		return this.script;
	},

	success: function(args){
		if (!this.running) return;
		this.clear()
			.fireEvent('complete', args).fireEvent('success', args)
			.callChain();
	},

	cancel: function(){
		if (this.running) this.clear().fireEvent('cancel');
		return this;
	},

	isRunning: function(){
		return !!this.running;
	},

	clear: function(){
		this.running = false;
		if (this.script){
			this.script.destroy();
			this.script = null;
		}
		return this;
	},

	timeout: function(){
		if (this.running){
			this.running = false;
			this.fireEvent('timeout', [this.script.get('src'), this.script]).fireEvent('failure').cancel();
		}
		return this;
	}

});

Request.JSONP.counter = 0;
Request.JSONP.request_map = {};