<?php
/**
 * TJsonService and TJsonResponse class file.
 *
 * @author Wei Zhuo <weizhuo[at]gamil[dot]com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Web\Services
 */

namespace Prado\Web\Services;
use Prado\TApplication;
use Prado\Prado;
use Prado\Exceptions\TConfigurationException;
use Prado\Exceptions\THttpException;
use Prado\Web\Javascripts\TJavaScript;

/**
 * TJsonService class provides to end-users javascript content response in
 * JSON format.
 *
 * TJsonService manages a set of {@link TJsonResponse}, each
 * representing specific response with javascript content.
 * The service parameter, referring to the ID of the service, specifies
 * which javascript content to be provided to end-users.
 *
 * To use TJsonService, configure it in application configuration as follows,
 * <code>
 *  <service id="json" class="System.Web.Services.TJsonService">
 *    <json id="get_article" class="Path.To.JsonResponseClass1" .../>
 *    <json id="register_rating" class="Path.To.JsonResponseClass2" .../>
 *  </service>
 * </code>
 * where each JSON response is specified via a &lt;json&gt; element.
 * Initial property values can be configured in a &lt;json&gt; element.
 *
 *
 * PHP configuration style:
 * <code>
 *  'services' => array(
 *    'get_article' => array(
 *     'class' => 'Path.To.JsonResponseClass1',
 *     'properties' => array(
 *       ...
 *	    )
 *    )
 *  )
 * </code>
 *
 * To retrieve the JSON content provided by "get_article", use the URL
 * <code>index.php?json=get_article</code>
 *
 * @author Wei Zhuo <weizhuo[at]gmail[dot]com>
 * @author Carl G. Mathisen <carlgmathisen@gmail.com>
 * @package Prado\Web\Services
 * @since 3.1
 */
class TJsonService extends \Prado\TService
{
	/**
	 * @var array registered services
	 */
	private $_services=array();

	/**
	 * Initializes this module.
	 * This method is required by the IModule interface.
	 * @param mixed configuration for this module, can be null
	 */
	public function init($xml)
	{
		$this->loadJsonServices($xml);
	}

	/**
	 * Load the service definitions.
	 * @param mixed configuration for this module, can be null
	 */
	protected function loadJsonServices($config)
	{
		if($this->getApplication()->getConfigurationType()==TApplication::CONFIG_TYPE_PHP)
		{
			if(is_array($config))
			{
				foreach($config['json'] as $id => $json)
					$this->_services[$id] = $json;
			}
		}
		else
		{
			foreach($config->getElementsByTagName('json') as $json)
			{
				if(($id=$json->getAttribute('id'))!==null)
					$this->_services[$id]=$json;
				else
					throw new TConfigurationException('jsonservice_id_required');
			}
		}
	}

	/**
	 * Runs the service.
	 * This method is invoked by application automatically.
	 */
	public function run()
	{
		$id=$this->getRequest()->getServiceParameter();
		if(isset($this->_services[$id]))
		{
			$serviceConfig=$this->_services[$id];
			if($this->getApplication()->getConfigurationType()==TApplication::CONFIG_TYPE_PHP)
			{
				if(isset($serviceConfig['class']))
				{
					$service=Prado::createComponent($serviceConfig['class']);
					if($service instanceof TJsonResponse)
					{
						$properties = isset($serviceConfig['properties'])?$serviceConfig['properties']:array();
						$this->createJsonResponse($service,$properties,$serviceConfig);
					}
					else
						throw new TConfigurationException('jsonservice_response_type_invalid',$id);
				}
				else
					throw new TConfigurationException('jsonservice_class_required',$id);
			}
			else
			{
				$properties=$serviceConfig->getAttributes();
				if(($class=$properties->remove('class'))!==null)
				{
					$service=Prado::createComponent($class);
					if($service instanceof TJsonResponse)
						$this->createJsonResponse($service,$properties,$serviceConfig);
					else
						throw new TConfigurationException('jsonservice_response_type_invalid',$id);
				}
				else
					throw new TConfigurationException('jsonservice_class_required',$id);
			}
		}
		else
			throw new THttpException(404,'jsonservice_provider_unknown',$id);
	}

	/**
	 * Renders content provided by TJsonResponse::getJsonContent() as
	 * javascript in JSON format.
	 */
	protected function createJsonResponse($service,$properties,$config)
	{
		// init service properties
		foreach($properties as $name=>$value)
			$service->setSubproperty($name,$value);
		$service->init($config);

		//send content if not null
		if(($content=$service->getJsonContent())!==null)
		{
			$response = $this->getResponse();
			$response->setContentType('application/json');
			$response->setCharset('UTF-8');
			//send content
			$response->write(TJavaScript::jsonEncode($content));
		}
	}
}