/*!
 * 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 = JSONPPolling;

/**
 * JSON-P polling transport.
 *
 * @api public
 */

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

	this.head = 'io.j[0](';
	this.foot = ');';

	if ( data.query.i ) {
		this.head = 'io.j[' + data.query.i + '](';
	}
}
;

/**
 * Inherits from Transport.
 */

JSONPPolling.prototype.__proto__ = HTTPPolling.prototype;

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

JSONPPolling.prototype.name = 'jsonppolling';

/**
 * Make sure POST are decoded.
 */

JSONPPolling.prototype.postEncoded = true;

/**
 * Handles incoming data.
 * Due to a bug in \n handling by browsers, we expect a JSONified string.
 *
 * @api private
 */

JSONPPolling.prototype.onData = function ( data ) {
	try {
		data = JSON.parse( data );
	} catch ( e ) {
		this.error( 'parse', 'reconnect' );
		return;
	}

	HTTPPolling.prototype.onData.call( this, data );
};

/**
 * Performs the write.
 *
 * @api private
 */

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

	var data = data === undefined
		? '' : this.head + JSON.stringify( data ) + this.foot;

	this.response.writeHead( 200, {
		'Content-Type' : 'text/javascript; charset=UTF-8', 'Content-Length' : Buffer.byteLength( data ), 'Connection' : 'Keep-Alive', 'X-XSS-Protection' : '0'
	} );

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