/*!
 * socket.io-node
 * Copyright(c) 2011 LearnBoost <dev@learnboost.com>
 * MIT Licensed
 */

/**
 * Module requirements.
 */

var HTTPPolling = require( './http-polling' );

/**
 * Export the constructor.
 */

exports = module.exports = XHRPolling;

/**
 * Ajax polling transport.
 *
 * @api public
 */

function XHRPolling( mng, data, req ) {
	HTTPPolling.call( this, mng, data, req );
}
;

/**
 * Inherits from Transport.
 */

XHRPolling.prototype.__proto__ = HTTPPolling.prototype;

/**
 * Transport name
 *
 * @api public
 */

XHRPolling.prototype.name = 'xhr-polling';

/**
 * Frames data prior to write.
 *
 * @api private
 */

XHRPolling.prototype.doWrite = function ( data ) {
	HTTPPolling.prototype.doWrite.call( this );

	var origin = this.req.headers.origin
		, headers = {
			'Content-Type' : 'text/plain; charset=UTF-8', 'Content-Length' : data === undefined ? 0 : Buffer.byteLength( data ), 'Connection' : 'Keep-Alive'
		};

	if ( origin ) {
		// https://developer.mozilla.org/En/HTTP_Access_Control
		headers['Access-Control-Allow-Origin'] = origin;
		headers['Access-Control-Allow-Credentials'] = 'true';
	}

	this.response.writeHead( 200, headers );
	this.response.write( data );
	this.log.debug( this.name + ' writing', data );
};