<?php

/**
 * Deal with redirects
 * @package framework
 * @subpackage dispatch
 */

trait Hm_Dispatch_Redirect {

    /**
     * Redirect after an HTTP POST form
     * @param Hm_Request $request request object
     * @param object $session session object
     * @param Hm_Module_Exec $mod_exec module manager object
     * @return boolean
     */
    private function post_redirect($request, $session, $mod_exec) {
        if (!empty($request->post) && $request->type == 'HTTP') {
            $this->forward_messages($session, $request);
            $session->end();
            $this->redirect_to_url($mod_exec);
            $this->redirect_to_current($request);
            return true;
        }
        return false;
    }

    /**
     * Redirect to the current url
     * @param Hm_Request $request
     * @return void
     */
    private function redirect_to_current($request) {
        if (array_key_exists('REQUEST_URI', $request->server)) {
            Hm_Dispatch::page_redirect($this->validate_request_uri($request->server['REQUEST_URI']));
        }
    }

    /**
     * Redirect to a specified url
     * @param object $mod_exec
     * @return void
     */
    private function redirect_to_url($mod_exec) {
        if (!empty($mod_exec->handler_response['redirect_url'])) {
            Hm_Dispatch::page_redirect($mod_exec->handler_response['redirect_url']);
        }
    }

    /**
     * Forward messages on a POST redirect
     * @param object $session session object
     * @return void
     */
    private function forward_messages($session, $request) {
        $msgs = Hm_Msgs::get();
        if (!empty($msgs)) {
            $session->secure_cookie($request, 'hm_msgs', base64_encode(json_encode($msgs)));
        }
    }

    /**
     * Validate a request uri
     * @param string $uri URI to validate
     * @return string
     */
    public function validate_request_uri($uri) {
        $uri = html_entity_decode($uri);
        if ($uri === '') {
            return '/';
        }
        $parts = parse_url($uri);
        if (array_key_exists('scheme', $parts)) {
            return '/';
        }
        if ($parts === false || !array_key_exists('path', $parts) || mb_strpos($parts['path'], '..') !== false) {
            return '/';
        }
        return $uri;
    }


    /**
     * Redirect the page after a POST form is submitted and forward any user notices
     * @param Hm_Request $request request object
     * @param Hm_Module_Exec $mod_exec module manager object
     * @param object $session session object
     * @return string|false
     */
    public function check_for_redirect($request, $mod_exec, $session) {
        if (!empty($mod_exec->handler_response['no_redirect'])) {
            return 'noredirect';
        }
        if ($this->post_redirect($request, $session, $mod_exec)) {
            return 'redirect';
        } elseif (!empty($mod_exec->handler_response['redirect_url'])) {
            $session->end();
            $this->redirect_to_url($mod_exec);
            return 'redirect';
        } elseif ($this->unpack_messages($request, $session)) {
            return 'msg_forward';
        }
        return false;
    }

    /**
     * Unpack forwarded messages
     * @param Hm_Request $request request object
     * @param object $session session object
     * @return boolean
     */
    public function unpack_messages($request, $session) {
        if (!empty($request->cookie['hm_msgs'])) {
            $msgs = @json_decode(base64_decode($request->cookie['hm_msgs']), true);
            if (is_array($msgs)) {
                array_walk($msgs, function($v) { Hm_Msgs::add($v); });
            }
            $session->delete_cookie($request, 'hm_msgs');
            return true;
        }
        return false;
    }

    /**
     * Perform an HTTP redirect
     * @param string $url url to redirect to
     * @param int $status current HTTP status
     * @return void
     */
    static public function page_redirect($url, $status = false) {
        if (DEBUG_MODE) {
            Hm_Debug::add(sprintf('Redirecting to %s', $url));
            Hm_Debug::load_page_stats();
            Hm_Debug::show();
        }
        if ($status == 303) {
            Hm_Debug::add('Redirect loop found');
            Hm_Functions::cease('Redirect loop discovered');
        }
        Hm_Functions::header('HTTP/1.1 303 Found');
        Hm_Functions::header('Location: '.$url);
        Hm_Functions::cease();
    }

}

/**
 * Page request router that ties all the framework pieces together
 * @package framework
 * @subpackage dispatch
 */

class Hm_Dispatch {

    use Hm_Dispatch_Redirect;

    public $site_config;
    public $request;
    public $session;
    public $module_exec;
    public $page;
    public $output;

    /**
     * Setup object needed to process a request
     * @param object $config site configuration
     */
    public function __construct($config) {

        /* get the site config defined in the config/app.php file */
        $this->site_config = $config;

        /* check for the site module set override */
        $this->load_site_lib();

        /* setup a session handler, but don't actually start a session yet */
        $session_config = new Hm_Session_Setup($this->site_config);
        $this->session = $session_config->setup_session();

        /* instantiate the module runner */
        $this->module_exec = new Hm_Module_Exec($this->site_config);

        /* process request input using the white-lists defined in modules */
        $this->request = new Hm_Request($this->module_exec->filters, $config);

        /* do it */
        $this->process_request();
    }

    /**
     * Possibly include the site module lib.php overrides
     * @return void
     */
    private function load_site_lib() {
        if (!is_array($this->site_config->get_modules()) || !in_array('site', $this->site_config->get_modules(), true)) {
            return;
        }
        if (is_readable(APP_PATH.'modules/site/lib.php')) {
            Hm_Debug::add('Including site module set lib.php');
            require APP_PATH.'modules/site/lib.php';
        }
    }

    /**
     * Process a request
     * @return void
     */
    private function process_request() {

        /* get the request identifier */
        $this->get_page($this->module_exec->filters, $this->request);

        /* load up the module requirements */
        $this->module_exec->load_module_sets($this->page);

        /* run handler modules to process input and perform actions */
        $this->module_exec->run_handler_modules($this->request, $this->session, $this->page);

        /* clean up any network connections */
        $this->close_connections();

        /* check for update settings on login */
        $this->save_settings_on_login();

        /* check to see if a handler module told us to redirect the browser */
        $this->check_for_redirect($this->request, $this->module_exec, $this->session);

        /* save and close a session if one is open */
        $active_session = $this->save_session();

        /* run the output formatting modules */
        $this->module_exec->run_output_modules($this->request, $active_session, $this->page,
            $this->module_exec->handler_response);

        /* output content to the browser */
        $this->render_output();
    }

    /**
     * Check for a flag to save settings on login
     */
    private function save_settings_on_login() {
        if (!$this->session->loaded) {
            return;
        }
        if ($this->module_exec->user_config->save_on_login) {
            $this->module_exec->user_config->save($this->request->post['username'], $this->request->post['password']);
        }
    }

    /**
     * Close network connections if they exist
     * @return void
     */
    private function close_connections() {
        foreach (['Hm_IMAP_List', 'Hm_SMTP_List'] as $class) {
            if (Hm_Functions::class_exists($class)) {
                $class::clean_up();
            }
        }
    }

    /**
     * Close and save the session
     * @return bool true if the session is active
     */
    private function save_session() {
        $res = $this->session->is_active();
        $this->session->end();
        return $res;
    }

    /**
     * Format and send the request output to the browser
     * @return void
     */
    private function render_output() {
        $formatter = new $this->request->format($this->site_config);
        $class = $this->site_config->get('output_class', 'Hm_Output_HTTP');
        $renderer = new $class;
        $content = $formatter->content($this->module_exec->output_response, $this->request->allowed_output);
        /* TODO: might be a good idea to use a custom render class that can return
         * the output on demand */
        $this->output = $renderer->send_response($content, $this->module_exec->output_data);
    }

    /**
     * Get a list of valid pages
     * @param array $filters list of filters
     * @param return array
     */
    private function get_pages($filters) {
        return $filters['allowed_pages'] ?? [];
    }

    /**
     * Check for a valid ajax request
     * @param Hm_Request $request request details
     * @param array $filters list of filters
     * @return boolean
     */
    public function validate_ajax_request($request, $filters) {
        return $this->validate_hook($request->get, $filters) || $this->validate_hook($request->post, $filters);
    }

    /**
     * Validates ajax hook
     * @param array $input POST or GET data
     * @param array $filters list of filters
     * @return boolean
     */
    private function validate_hook($input, $filters) {
        if (array_key_exists('hm_ajax_hook', $input)) {
            if (in_array($input['hm_ajax_hook'], $this->get_pages($filters), true)) {
                return true;
            } else {
                Hm_Functions::cease(json_encode(['status' => 'not callable']));
            }
        }
        return false;
    }

    /**
     * Determine the page id
     * @param array $filters list of filters
     * @param Hm_Request $request request details
     * @return void
     */
    public function get_page($filters, $request) {
        $this->page = 'notfound';
        if ($request->type == 'AJAX' && $this->validate_ajax_request($request, $filters)) {
            $this->page = $request->get['hm_ajax_hook'] ?? $request->post['hm_ajax_hook'];
        } elseif (array_key_exists('page', $request->get) && in_array($request->get['page'], $this->get_pages($filters), true)) {
            $this->page = $request->get['page'];
        } elseif (!array_key_exists('page', $request->get)) {
            $this->page = 'home';
        }
        $this->module_exec->page = $this->page;
        Hm_Debug::add('Page ID: '.$this->page);
    }

    /**
     * Check to see if PHP is configured properly
     * @return bool
     */
    static public function is_php_setup() {
        return
            version_compare(PHP_VERSION, '7.4', '>=') &&
            Hm_Functions::function_exists('mb_strpos') &&
            Hm_Functions::function_exists('curl_exec') &&
            Hm_Functions::function_exists('openssl_random_pseudo_bytes') &&
            Hm_Functions::class_exists('PDO');
    }
}
