<?php

/**
 * Joomla! Content Management System
 *
 * @copyright  (C) 2019 Open Source Matters, Inc. <https://www.joomla.org>
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\CMS\Application;

use Joomla\Application\Web\WebClient;
use Joomla\CMS\Access\Exception\AuthenticationFailed;
use Joomla\CMS\Component\ComponentHelper;
use Joomla\CMS\Factory;
use Joomla\CMS\Plugin\PluginHelper;
use Joomla\CMS\Router\ApiRouter;
use Joomla\CMS\Router\Exception\RouteNotFoundException;
use Joomla\CMS\Uri\Uri;
use Joomla\DI\Container;
use Joomla\Input\Json as JInputJson;
use Joomla\Registry\Registry;
use Negotiation\Accept;
use Negotiation\Exception\InvalidArgument;
use Negotiation\Negotiator;

/**
 * Joomla! API Application class
 *
 * @since  4.0.0
 */
final class ApiApplication extends CMSApplication
{
    /**
     * Maps extension types to their
     *
     * @var    array
     * @since  4.0.0
     */
    protected $formatMapper = array();

    /**
     * The authentication plugin type
     *
     * @var    string
     * @since  4.0.0
     */
    protected $authenticationPluginType = 'api-authentication';

    /**
     * Class constructor.
     *
     * @param   JInputJson  $input      An optional argument to provide dependency injection for the application's input
     *                                  object.  If the argument is a JInput object that object will become the
     *                                  application's input object, otherwise a default input object is created.
     * @param   Registry    $config     An optional argument to provide dependency injection for the application's config
     *                                  object.  If the argument is a Registry object that object will become the
     *                                  application's config object, otherwise a default config object is created.
     * @param   WebClient   $client     An optional argument to provide dependency injection for the application's client
     *                                  object.  If the argument is a WebClient object that object will become the
     *                                  application's client object, otherwise a default client object is created.
     * @param   Container   $container  Dependency injection container.
     *
     * @since   4.0.0
     */
    public function __construct(JInputJson $input = null, Registry $config = null, WebClient $client = null, Container $container = null)
    {
        // Register the application name
        $this->name = 'api';

        // Register the client ID
        $this->clientId = 3;

        // Execute the parent constructor
        parent::__construct($input, $config, $client, $container);

        $this->addFormatMap('application/json', 'json');
        $this->addFormatMap('application/vnd.api+json', 'jsonapi');

        // Set the root in the URI based on the application name
        Uri::root(null, str_ireplace('/' . $this->getName(), '', Uri::base(true)));
    }


    /**
     * Method to run the application routines.
     *
     * Most likely you will want to instantiate a controller and execute it, or perform some sort of task directly.
     *
     * @return  void
     *
     * @since   4.0.0
     */
    protected function doExecute()
    {
        // Initialise the application
        $this->initialiseApp();

        // Mark afterInitialise in the profiler.
        JDEBUG ? $this->profiler->mark('afterInitialise') : null;

        // Route the application
        $this->route();

        // Mark afterApiRoute in the profiler.
        JDEBUG ? $this->profiler->mark('afterApiRoute') : null;

        // Dispatch the application
        $this->dispatch();

        // Mark afterDispatch in the profiler.
        JDEBUG ? $this->profiler->mark('afterDispatch') : null;
    }

    /**
     * Adds a mapping from a content type to the format stored. Note the format type cannot be overwritten.
     *
     * @param   string  $contentHeader  The content header
     * @param   string  $format         The content type format
     *
     * @return  void
     *
     * @since   4.0.0
     */
    public function addFormatMap($contentHeader, $format)
    {
        if (!\array_key_exists($contentHeader, $this->formatMapper)) {
            $this->formatMapper[$contentHeader] = $format;
        }
    }

    /**
     * Rendering is the process of pushing the document buffers into the template
     * placeholders, retrieving data from the document and pushing it into
     * the application response buffer.
     *
     * @return  void
     *
     * @since   4.0.0
     *
     * @note    Rendering should be overridden to get rid of the theme files.
     */
    protected function render()
    {
        // Render the document
        $this->setBody($this->document->render($this->allowCache()));
    }

    /**
     * Method to send the application response to the client.  All headers will be sent prior to the main application output data.
     *
     * @param   array  $options  An optional argument to enable CORS. (Temporary)
     *
     * @return  void
     *
     * @since   4.0.0
     */
    protected function respond($options = array())
    {
        // Set the Joomla! API signature
        $this->setHeader('X-Powered-By', 'JoomlaAPI/1.0', true);

        $forceCORS = (int) $this->get('cors');

        if ($forceCORS) {
            /**
            * Enable CORS (Cross-origin resource sharing)
            * Obtain allowed CORS origin from Global Settings.
            * Set to * (=all) if not set.
            */
            $allowedOrigin = $this->get('cors_allow_origin', '*');
            $this->setHeader('Access-Control-Allow-Origin', $allowedOrigin, true);
            $this->setHeader('Access-Control-Allow-Headers', 'Authorization');

            if ($this->input->server->getString('HTTP_ORIGIN', null) !== null) {
                $this->setHeader('Access-Control-Allow-Origin', $this->input->server->getString('HTTP_ORIGIN'), true);
                $this->setHeader('Access-Control-Allow-Credentials', 'true', true);
            }
        }

        // Parent function can be overridden later on for debugging.
        parent::respond();
    }

    /**
     * Gets the name of the current template.
     *
     * @param   boolean  $params  True to return the template parameters
     *
     * @return  string|\stdClass
     *
     * @since   4.0.0
     */
    public function getTemplate($params = false)
    {
        // The API application should not need to use a template
        if ($params) {
            $template              = new \stdClass();
            $template->template    = 'system';
            $template->params      = new Registry();
            $template->inheritable = 0;
            $template->parent      = '';

            return $template;
        }

        return 'system';
    }

    /**
     * Route the application.
     *
     * Routing is the process of examining the request environment to determine which
     * component should receive the request. The component optional parameters
     * are then set in the request object to be processed when the application is being
     * dispatched.
     *
     * @return  void
     *
     * @since   4.0.0
     */
    protected function route()
    {
        $router = $this->getContainer()->get(ApiRouter::class);

        // Trigger the onBeforeApiRoute event.
        PluginHelper::importPlugin('webservices');
        $this->triggerEvent('onBeforeApiRoute', array(&$router, $this));
        $caught404 = false;
        $method    = $this->input->getMethod();

        try {
            $this->handlePreflight($method, $router);

            $route = $router->parseApiRoute($method);
        } catch (RouteNotFoundException $e) {
            $caught404 = true;
        }

        /**
         * Now we have an API perform content negotiation to ensure we have a valid header. Assume if the route doesn't
         * tell us otherwise it uses the plain JSON API
         */
        $priorities = array('application/vnd.api+json');

        if (!$caught404 && \array_key_exists('format', $route['vars'])) {
            $priorities = $route['vars']['format'];
        }

        $negotiator = new Negotiator();

        try {
            $mediaType = $negotiator->getBest($this->input->server->getString('HTTP_ACCEPT'), $priorities);
        } catch (InvalidArgument $e) {
            $mediaType = null;
        }

        // If we can't find a match bail with a 406 - Not Acceptable
        if ($mediaType === null) {
            throw new Exception\NotAcceptable('Could not match accept header', 406);
        }

        /** @var $mediaType Accept */
        $format = $mediaType->getValue();

        if (\array_key_exists($mediaType->getValue(), $this->formatMapper)) {
            $format = $this->formatMapper[$mediaType->getValue()];
        }

        $this->input->set('format', $format);

        if ($caught404) {
            throw $e;
        }

        $this->input->set('option', $route['vars']['component']);
        $this->input->set('controller', $route['controller']);
        $this->input->set('task', $route['task']);

        foreach ($route['vars'] as $key => $value) {
            if ($key !== 'component') {
                if ($this->input->getMethod() === 'POST') {
                    $this->input->post->set($key, $value);
                } else {
                    $this->input->set($key, $value);
                }
            }
        }

        $this->triggerEvent('onAfterApiRoute', array($this));

        if (!isset($route['vars']['public']) || $route['vars']['public'] === false) {
            if (!$this->login(array('username' => ''), array('silent' => true, 'action' => 'core.login.api'))) {
                throw new AuthenticationFailed();
            }
        }
    }

    /**
     * Handles preflight requests.
     *
     * @param   String     $method  The REST verb
     *
     * @param   ApiRouter  $router  The API Routing object
     *
     * @return  void
     *
     * @since   4.0.0
     */
    protected function handlePreflight($method, $router)
    {
        /**
        * If not an OPTIONS request or CORS is not enabled,
        * there's nothing useful to do here.
        */
        if ($method !== 'OPTIONS' || !(int) $this->get('cors')) {
            return;
        }

        // Extract routes matching current route from all known routes.
        $matchingRoutes = $router->getMatchingRoutes();

        // Extract exposed methods from matching routes.
        $matchingRoutesMethods = array_unique(
            array_reduce(
                $matchingRoutes,
                function ($carry, $route) {
                    return array_merge($carry, $route->getMethods());
                },
                []
            )
        );

        /**
        * Obtain allowed CORS origin from Global Settings.
        * Set to * (=all) if not set.
        */
        $allowedOrigin = $this->get('cors_allow_origin', '*');

        /**
        * Obtain allowed CORS headers from Global Settings.
        * Set to sensible default if not set.
        */
        $allowedHeaders = $this->get('cors_allow_headers', 'Content-Type,X-Joomla-Token');

        /**
        * Obtain allowed CORS methods from Global Settings.
        * Set to methods exposed by current route if not set.
        */
        $allowedMethods = $this->get('cors_allow_methods', implode(',', $matchingRoutesMethods));

        // No use to go through the regular route handling hassle,
        // so let's simply output the headers and exit.
        $this->setHeader('status', '204');
        $this->setHeader('Access-Control-Allow-Origin', $allowedOrigin);
        $this->setHeader('Access-Control-Allow-Headers', $allowedHeaders);
        $this->setHeader('Access-Control-Allow-Methods', $allowedMethods);
        $this->sendHeaders();

        $this->close();
    }

    /**
     * Returns the application Router object.
     *
     * @return  ApiRouter
     *
     * @since      4.0.0
     * @deprecated 5.0 Inject the router or load it from the dependency injection container
     */
    public function getApiRouter()
    {
        return $this->getContainer()->get(ApiRouter::class);
    }

    /**
     * Dispatch the application
     *
     * @param   string  $component  The component which is being rendered.
     *
     * @return  void
     *
     * @since   4.0.0
     */
    public function dispatch($component = null)
    {
        // Get the component if not set.
        if (!$component) {
            $component = $this->input->get('option', null);
        }

        // Load the document to the API
        $this->loadDocument();

        // Set up the params
        $document = Factory::getDocument();

        // Register the document object with Factory
        Factory::$document = $document;

        $contents = ComponentHelper::renderComponent($component);
        $document->setBuffer($contents, 'component');

        // Trigger the onAfterDispatch event.
        PluginHelper::importPlugin('system');
        $this->triggerEvent('onAfterDispatch');
    }
}
