<?php
/**
 * @package     Joomla.Platform
 * @subpackage  Twitter
 *
 * @copyright   Copyright (C) 2005 - 2012 Open Source Matters, Inc. All rights reserved.
 * @license     GNU General Public License version 2 or later; see LICENSE
 */

defined('JPATH_PLATFORM') or die();

/**
 * Twitter API object class for the Joomla Platform.
 *
 * @package     Joomla.Platform
 * @subpackage  Twitter
 * @since       12.3
 */
abstract class JTwitterObject
{
	/**
	 * @var    JRegistry  Options for the Twitter object.
	 * @since  12.3
	 */
	protected $options;

	/**
	 * @var    JHttp  The HTTP client object to use in sending HTTP requests.
	 * @since  12.3
	 */
	protected $client;

	/**
	 * @var JTwitterOAuth The OAuth client.
	 * @since 12.3
	 */
	protected $oauth;

	/**
	 * Constructor.
	 *
	 * @param   JRegistry      &$options  Twitter options object.
	 * @param   JTwitterHttp   $client    The HTTP client object.
	 * @param   JTwitterOAuth  $oauth     The OAuth client.
	 *
	 * @since   12.3
	 */
	public function __construct(JRegistry &$options = null, JHttp $client = null, JTwitterOAuth $oauth = null)
	{
		$this->options = isset($options) ? $options : new JRegistry;
		$this->client = isset($client) ? $client : new JHttp($this->options);
		$this->oauth = $oauth;
	}

	/**
	 * Method to check the rate limit for the requesting IP address
	 *
	 * @param   string  $resource  A resource or a comma-separated list of resource families you want to know the current rate limit disposition for.
	 * @param   string  $action    An action for the specified resource, if only one resource is specified.
	 *
	 * @return  void
	 *
	 * @since   12.3
	 * @throws  RuntimeException
	 */
	public function checkRateLimit($resource = null, $action = null)
	{
		// Check the rate limit for remaining hits
		$rate_limit = $this->getRateLimit($resource);

		$property = '/' . $resource;

		if (!is_null($action))
		{
			$property .= '/' . $action;
		}

		if ($rate_limit->resources->$resource->$property->remaining == 0)
		{
			// The IP has exceeded the Twitter API rate limit
			throw new RuntimeException('This server has exceed the Twitter API rate limit for the given period.  The limit will reset at '
						. $rate_limit->resources->$resource->$property->reset
			);
		}
	}

	/**
	 * Method to build and return a full request URL for the request.  This method will
	 * add appropriate pagination details if necessary and also prepend the API url
	 * to have a complete URL for the request.
	 *
	 * @param   string  $path        URL to inflect
	 * @param   array   $parameters  The parameters passed in the URL.
	 *
	 * @return  string  The request URL.
	 *
	 * @since   12.3
	 */
	public function fetchUrl($path, $parameters = null)
	{
		if ($parameters)
		{
			foreach ($parameters as $key => $value)
			{
				if (strpos($path, '?') === false)
				{
					$path .= '?' . $key . '=' . $value;
				}
				else
				{
					$path .= '&' . $key . '=' . $value;
				}
			}
		}

		// Get a new JUri object fousing the api url and given path.
		if (strpos($path, 'http://search.twitter.com/search.json') === false)
		{
			$uri = new JUri($this->options->get('api.url') . $path);
		}
		else
		{
			$uri = new JUri($path);
		}

		return (string) $uri;
	}

	/**
	 * Method to retrieve the rate limit for the requesting IP address
	 *
	 * @param   string  $resource  A resource or a comma-separated list of resource families you want to know the current rate limit disposition for.
	 *
	 * @return  array  The JSON response decoded
	 *
	 * @since   12.3
	 */
	public function getRateLimit($resource)
	{
		// Build the request path.
		$path = '/application/rate_limit_status.json';

		if (!is_null($resource))
		{
			return $this->sendRequest($path, 'GET',  array('resources' => $resource));
		}

		return $this->sendRequest($path);
	}

	/**
	 * Method to send the request.
	 *
	 * @param   string  $path     The path of the request to make
	 * @param   string  $method   The request method.
	 * @param   mixed   $data     Either an associative array or a string to be sent with the post request.
	 * @param   array   $headers  An array of name-value pairs to include in the header of the request
	 *
	 * @return  array  The decoded JSON response
	 *
	 * @since   12.3
	 */
	public function sendRequest($path, $method = 'GET', $data = array(), $headers = array())
	{
		// Get the access token.
		$token = $this->oauth->getToken();

		// Set parameters.
		$parameters['oauth_token'] = $token['key'];

		// Send the request.
		$response = $this->oauth->oauthRequest($this->fetchUrl($path), $method, $parameters, $data, $headers);

		if (strpos($path, 'update_with_media') !== false)
		{
			// Check Media Rate Limit.
			$response_headers = $response->headers;

			if ($response_headers['x-mediaratelimit-remaining'] == 0)
			{
				// The IP has exceeded the Twitter API media rate limit
				throw new RuntimeException('This server has exceed the Twitter API media rate limit for the given period.  The limit will reset in '
						. $response_headers['x-mediaratelimit-reset'] . 'seconds.'
				);
			}
		}

		if (strpos($response->body, 'redirected') !== false)
		{
			return $response->headers['Location'];
		}

		return json_decode($response->body);
	}

	/**
	 * Get an option from the JTwitterObject instance.
	 *
	 * @param   string  $key  The name of the option to get.
	 *
	 * @return  mixed  The option value.
	 *
	 * @since   12.3
	 */
	public function getOption($key)
	{
		return $this->options->get($key);
	}

	/**
	 * Set an option for the JTwitterObject instance.
	 *
	 * @param   string  $key    The name of the option to set.
	 * @param   mixed   $value  The option value to set.
	 *
	 * @return  JTwitterObject  This object for method chaining.
	 *
	 * @since   12.3
	 */
	public function setOption($key, $value)
	{
		$this->options->set($key, $value);

		return $this;
	}
}