<?php namespace CodeIgniter;

/**
 * CodeIgniter
 *
 * An open source application development framework for PHP
 *
 * This content is released under the MIT License (MIT)
 *
 * Copyright (c) 2014 - 2017, British Columbia Institute of Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @package	CodeIgniter
 * @author	CodeIgniter Dev Team
 * @copyright	Copyright (c) 2014 - 2017, British Columbia Institute of Technology (http://bcit.ca/)
 * @license	https://opensource.org/licenses/MIT	MIT License
 * @link	https://codeigniter.com
 * @since	Version 3.0.0
 * @filesource
 */

use Config\Cache;
use CodeIgniter\HTTP\URI;
use CodeIgniter\Debug\Timer;
use CodeIgniter\Hooks\Hooks;
use CodeIgniter\Config\DotEnv;
use CodeIgniter\HTTP\Response;
use CodeIgniter\HTTP\CLIRequest;
use CodeIgniter\Router\RouteCollectionInterface;

/**
 * This class is the core of the framework, and will analyse the
 * request, route it to a controller, and send back the response.
 * Of course, there are variations to that flow, but this is the brains.
 */
class CodeIgniter
{
    /**
     * The current version of CodeIgniter Framework
     */
    const CI_VERSION = '4.0-dev';

    /**
     * App startup time.
     * @var mixed
     */
    protected $startTime;

    /**
     * Amount of memory at app start.
     * @var int
     */
    protected $startMemory;

    /**
     * Total app execution time
     * @var float
     */
    protected $totalTime;

    /**
     * Main application configuration
     * @var \Config\App
     */
    protected $config;

    /**
     * Timer instance.
     * @var Timer
     */
    protected $benchmark;

    /**
     * Current request.
     * @var \CodeIgniter\HTTP\Request
     */
    protected $request;

    /**
     * Current response.
     * @var \CodeIgniter\HTTP\Response
     */
    protected $response;

    /**
     * Router to use.
     * @var \CodeIgniter\Router\Router
     */
    protected $router;

    /**
     * Controller to use.
     * @var string|\Closure
     */
    protected $controller;

    /**
     * Controller method to invoke.
     * @var string
     */
    protected $method;

    /**
     * Output handler to use.
     * @var string
     */
    protected $output;

    /**
     * Cache expiration time
     * @var int
     */
    protected static $cacheTTL = 0;

    /**
     * Request path to use.
     * @var string
     */
    protected $path;

    //--------------------------------------------------------------------

    public function __construct($config)
    {
        $this->startTime = microtime(true);
        $this->startMemory = memory_get_usage(true);
        $this->config = $config;
    }

    //--------------------------------------------------------------------

    /**
     * Handles some basic app and environment setup.
     */
    public function initialize()
    {
        // Set default timezone on the server
        date_default_timezone_set($this->config->appTimezone ?? 'UTC');

        // Setup Exception Handling
        Config\Services::exceptions($this->config, true)
                ->initialize();

        $this->detectEnvironment();
        $this->bootstrapEnvironment();
        $this->loadEnvironment();

        if (CI_DEBUG)
        {
            require_once BASEPATH.'ThirdParty/Kint/Kint.class.php';
        }
    }

    //--------------------------------------------------------------------

    /**
     * Launch the application!
     *
     * This is "the loop" if you will. The main entry point into the script
     * that gets the required class instances, fires off the filters,
     * tries to route the response, loads the controller and generally
     * makes all of the pieces work together.
     *
     * @param \CodeIgniter\RouteCollectionInterface $routes
     */
    public function run(RouteCollectionInterface $routes = null)
    {
        $this->startBenchmark();

        $this->getRequestObject();
        $this->getResponseObject();

        $this->forceSecureAccess();

        // Check for a cached page. Execution will stop
        // if the page has been cached.
        $cacheConfig = new Cache();
        $this->displayCache($cacheConfig);

        try {
            $this->handleRequest($routes, $cacheConfig);
        }
        catch (Router\RedirectException $e)
        {
            $logger = Config\Services::logger();
            $logger->info('REDIRECTED ROUTE at '.$e->getMessage());

            // If the route is a 'redirect' route, it throws
            // the exception with the $to as the message
            $this->response->redirect($e->getMessage(), 'auto', $e->getCode());
            $this->callExit(EXIT_SUCCESS);
        }
            // Catch Response::redirect()
        catch (HTTP\RedirectException $e)
        {
            $this->callExit(EXIT_SUCCESS);
        }
        catch (PageNotFoundException $e)
        {
            $this->display404errors($e);
        }
    }

    //--------------------------------------------------------------------

    /**
     * Handles the main request logic and fires the controller.
     *
     * @param \CodeIgniter\Router\RouteCollectionInterface $routes
     * @param                                              $cacheConfig
     */
    protected function handleRequest(RouteCollectionInterface $routes = null, $cacheConfig)
    {
        $this->tryToRouteIt($routes);

        // Run "before" filters
        $filters = Config\Services::filters();
        $uri = $this->request instanceof CLIRequest
            ? $this->request->getPath()
            : $this->request->uri->getPath();

        $filters->run($uri, 'before');

        $returned = $this->startController();

        // Closure controller has run in startController().
        if ( ! is_callable($this->controller))
        {
            $controller = $this->createController();

            // Is there a "post_controller_constructor" hook?
            Hooks::trigger('post_controller_constructor');

            $returned = $this->runController($controller);
        }
		else
		{
			$this->benchmark->stop('controller_constructor');
			$this->benchmark->stop('controller');
		}

        // If $returned is a string, then the controller output something,
        // probably a view, instead of echoing it directly. Send it along
        // so it can be used with the output.
        $this->gatherOutput($cacheConfig, $returned);

        // Run "after" filters
        $response = $filters->run($uri, 'after');

        if ($response instanceof Response)
        {
            $this->response = $response;
        }

        // Save our current URI as the previous URI in the session
        // for safer, more accurate use with `previous_url()` helper function.
        $this->storePreviousURL($this->request->uri ?? $uri);

        unset($uri);

        $this->sendResponse();

        //--------------------------------------------------------------------
        // Is there a post-system hook?
        //--------------------------------------------------------------------
        Hooks::trigger('post_system');
    }

    //--------------------------------------------------------------------

    /**
     * You can load different configurations depending on your
     * current environment. Setting the environment also influences
     * things like logging and error reporting.
     *
     * This can be set to anything, but default usage is:
     *
     *     development
     *     testing
     *     production
     */
    protected function detectEnvironment()
    {
        // running under Continuous Integration server?
        if (getenv('CI') !== false)
        {
            define('ENVIRONMENT', 'testing');
        }
        else
        {
            define('ENVIRONMENT', isset($_SERVER['CI_ENV']) ? $_SERVER['CI_ENV'] : 'production');
        }
    }

    //--------------------------------------------------------------------

    /**
     * Load any custom boot files based upon the current environment.
     *
     * If no boot file exists, we shouldn't continue because something
     * is wrong. At the very least, they should have error reporting setup.
     */
    protected function bootstrapEnvironment()
    {
        if (file_exists(APPPATH.'Config/Boot/'.ENVIRONMENT.'.php'))
        {
            require_once APPPATH.'Config/Boot/'.ENVIRONMENT.'.php';
        }
        else
        {
            header('HTTP/1.1 503 Service Unavailable.', true, 503);
            echo 'The application environment is not set correctly.';
            exit(1); // EXIT_ERROR
        }
    }

    //--------------------------------------------------------------------

    /**
     * Loads any custom server config values from the .env file.
     */
    protected function loadEnvironment()
    {
        // Load environment settings from .env files
        // into $_SERVER and $_ENV
        require BASEPATH.'Config/DotEnv.php';

        $env = new DotEnv(ROOTPATH);
        $env->load();
    }

    //--------------------------------------------------------------------

    /**
     * Start the Benchmark
     *
     * The timer is used to display total script execution both in the
     * debug toolbar, and potentially on the displayed page.
     */
    protected function startBenchmark()
    {
        $this->startTime = microtime(true);

        $this->benchmark = Config\Services::timer();
        $this->benchmark->start('total_execution', $this->startTime);
        $this->benchmark->start('bootstrap');
    }

    //--------------------------------------------------------------------

    /**
     * Get our Request object, (either IncomingRequest or CLIRequest)
     * and set the server protocol based on the information provided
     * by the server.
     */
    protected function getRequestObject()
    {
        if (is_cli())
        {
            $this->request = Config\Services::clirequest($this->config);
        }
        else
        {
            $this->request = Config\Services::request($this->config);
            $this->request->setProtocolVersion($_SERVER['SERVER_PROTOCOL']);
        }
    }

    //--------------------------------------------------------------------

    /**
     * Get our Response object, and set some default values, including
     * the HTTP protocol version and a default successful response.
     */
    protected function getResponseObject()
    {
        $this->response = Config\Services::response($this->config);

        if ( ! is_cli())
        {
            $this->response->setProtocolVersion($this->request->getProtocolVersion());
        }

        // Assume success until proven otherwise.
        $this->response->setStatusCode(200);
    }

    //--------------------------------------------------------------------

    /**
     * Force Secure Site Access? If the config value 'forceGlobalSecureRequests'
     * is true, will enforce that all requests to this site are made through
     * HTTPS. Will redirect the user to the current page with HTTPS, as well
     * as set the HTTP Strict Transport Security header for those browsers
     * that support it.
     *
     * @param int $duration  How long the Strict Transport Security
     *                       should be enforced for this URL.
     */
    protected function forceSecureAccess($duration = 31536000)
    {
        if ($this->config->forceGlobalSecureRequests !== true)
        {
            return;
        }

        force_https($duration, $this->request, $this->response);
    }

    //--------------------------------------------------------------------

    /**
     * Determines if a response has been cached for the given URI.
     *
     * @param \Config\Cache $config
     *
     * @return bool
     */
    public function displayCache($config)
    {
        if ($cachedResponse = cache()->get($this->generateCacheName($config)))
        {
            $cachedResponse = unserialize($cachedResponse);
            if (!is_array($cachedResponse) || !isset($cachedResponse['output']) || !isset($cachedResponse['headers']))
            {
                throw new \Exception("Error unserializing page cache");
            }

            $headers = $cachedResponse['headers'];
            $output  = $cachedResponse['output'];

            // Clear all default headers
            foreach($this->response->getHeaders() as $key => $val) {
                $this->response->removeHeader($key);
            }

            // Set cached headers
            foreach($headers as $name => $value) {
                $this->response->setHeader($name, $value);
            }

            $output = $this->displayPerformanceMetrics($output);
            $this->response->setBody($output)->send();
            $this->callExit(EXIT_SUCCESS);
        };
    }


    //--------------------------------------------------------------------

    /**
     * Tells the app that the final output should be cached.
     *
     * @param int $time
     *
     * @return $this
     */
    public static function cache(int $time)
    {
        self::$cacheTTL = (int)$time;
    }

    //--------------------------------------------------------------------

    /**
     * Caches the full response from the current request. Used for
     * full-page caching for very high performance.
     *
     * @param \Config\Cache $config
     */
    public function cachePage(Cache $config)
    {
        $headers = [];
        foreach($this->response->getHeaders() as $header) {
            $headers[$header->getName()] = $header->getValueLine();
        }

        return cache()->save(
            $this->generateCacheName($config),
            serialize(['headers' => $headers, 'output' => $this->output]),
            self::$cacheTTL
        );

    }

    //--------------------------------------------------------------------

    /**
     * Returns an array with our basic performance stats collected.
     *
     * @return array
     */
    public function getPerformanceStats()
    {
        return [
            'startTime'	=> $this->startTime,
            'totalTime' => $this->totalTime,
            'startMemory' => $this->startMemory
        ];
    }

    //--------------------------------------------------------------------

    /**
     * Generates the cache name to use for our full-page caching.
     *
     * @param $config
     *
     * @return string
     */
    protected function generateCacheName($config): string
    {
        if (is_cli())
        {
            return md5($this->request->getPath());
        }

        $uri = $this->request->uri;

        if ($config->cacheQueryString)
        {
            $name = URI::createURIString(
                $uri->getScheme(),
                $uri->getAuthority(),
                $uri->getPath(),
                $uri->getQuery()
            );
        }
        else
        {
            $name = URI::createURIString(
                $uri->getScheme(),
                $uri->getAuthority(),
                $uri->getPath()
            );
        }

        return md5($name);
    }

    //--------------------------------------------------------------------

    /**
     * Replaces the memory_usage and elapsed_time tags.
     *
     * @param string $output
     *
     * @return string
     */
    public function displayPerformanceMetrics(string $output): string
    {
        $this->totalTime = $this->benchmark->getElapsedTime('total_execution');

        $output = str_replace('{elapsed_time}', $this->totalTime, $output);

        return $output;
    }

    //--------------------------------------------------------------------

    /**
     * Try to Route It - As it sounds like, works with the router to
     * match a route against the current URI. If the route is a
     * "redirect route", will also handle the redirect.
     *
     * @param RouteCollectionInterface $routes  An collection interface to use in place
     *                                          of the config file.
     */
    protected function tryToRouteIt(RouteCollectionInterface $routes = null)
    {
        if (empty($routes) || ! $routes instanceof RouteCollectionInterface)
        {
            require APPPATH.'Config/Routes.php';
        }

        // $routes is defined in Config/Routes.php
        $this->router = Config\Services::router($routes);

        $path = $this->determinePath();

        $this->benchmark->stop('bootstrap');
        $this->benchmark->start('routing');

        ob_start();

        $this->controller = $this->router->handle($path);
        $this->method     = $this->router->methodName();

        // If a {locale} segment was matched in the final route,
        // then we need to set the correct locale on our Request.
        if ($this->router->hasLocale())
        {
            $this->request->setLocale($this->router->getLocale());
        }

        $this->benchmark->stop('routing');
    }

    //--------------------------------------------------------------------

    /**
     * Determines the path to use for us to try to route to, based
     * on user input (setPath), or the CLI/IncomingRequest path.
     */
    protected function determinePath()
    {
        if (! empty($this->path))
        {
            return $this->path;
        }

        return is_cli()
            ? $this->request->getPath()
            : $this->request->uri->getPath();
    }

    //--------------------------------------------------------------------

    /**
     * Allows the request path to be set from outside the class,
     * instead of relying on CLIRequest or IncomingRequest for the path.
     *
     * This is primarily used by the Console.
     *
     * @param string $path
     *
     * @return $this
     */
    public function setPath(string $path)
    {
        $this->path = $path;

        return $this;
    }

    //--------------------------------------------------------------------

    /**
     * Now that everything has been setup, this method attempts to run the
     * controller method and make the script go. If it's not able to, will
     * show the appropriate Page Not Found error.
     */
    protected function startController()
    {
        $this->benchmark->start('controller');
        $this->benchmark->start('controller_constructor');

        // Is it routed to a Closure?
        if (is_object($this->controller) && (get_class($this->controller) == 'Closure'))
        {
            $controller = $this->controller;
            return $controller(...$this->router->params());
        }
        else
        {
            // No controller specified - we don't know what to do now.
            if (empty($this->controller))
            {
                throw new PageNotFoundException('Controller is empty.');
            }
            else
            {
                // Try to autoload the class
                if ( ! class_exists($this->controller, true) || $this->method[0] === '_')
                {
                    throw new PageNotFoundException('Controller or its method is not found.');
                }
                else if ( ! method_exists($this->controller, '_remap') &&
                          ! is_callable([$this->controller, $this->method], false)
                )
                {
                    throw new PageNotFoundException('Controller method is not found.');
                }
            }
        }
    }

    //--------------------------------------------------------------------

    /**
     * Instantiates the controller class.
     *
     * @return mixed
     */
    protected function createController()
    {
        $class = new $this->controller($this->request, $this->response);

        $this->benchmark->stop('controller_constructor');

        return $class;
    }

    //--------------------------------------------------------------------

    /**
     * Runs the controller, allowing for _remap methods to function.
     *
     * @param mixed $class
     *
     * @return mixed
     */
    protected function runController($class)
    {
        if (method_exists($class, '_remap'))
        {
            $output = $class->_remap($this->method, ...$this->router->params());
        }
        else
        {
            $output = $class->{$this->method}(...$this->router->params());
        }

        $this->benchmark->stop('controller');

        return $output;
    }

    //--------------------------------------------------------------------

    /**
     * Displays a 404 Page Not Found error. If set, will try to
     * call the 404Override controller/method that was set in routing config.
     *
     * @param PageNotFoundException $e
     */
    protected function display404errors(PageNotFoundException $e)
    {
        // Is there a 404 Override available?
        if ($override = $this->router->get404Override())
        {
            if ($override instanceof \Closure)
            {
                echo $override();
            }
            else if (is_array($override))
            {
                $this->benchmark->start('controller');
                $this->benchmark->start('controller_constructor');

                $this->controller = $override[0];
                $this->method     = $override[1];

                unset($override);

                $controller = $this->createController();
                $this->runController($controller);
            }

            $this->gatherOutput();
            $this->sendResponse();

            return;
        }

        // Display 404 Errors
        $this->response->setStatusCode(404);

        if (ENVIRONMENT !== 'testing') {
            if (ob_get_level() > 0) {
                ob_end_flush();
            }
        }
        else
        {
            // When testing, one is for phpunit, another is for test case.
            if (ob_get_level() > 2) {
                ob_end_flush();
            }
        }

        ob_start();

        // These might show as unused here - but don't delete!
        // They are used within the view files.
        $heading = 'Page Not Found';
        $message = $e->getMessage();

        // Show the 404 error page
        if (is_cli())
        {
            require APPPATH.'Views/errors/cli/error_404.php';
        }
        else
        {
            require APPPATH.'Views/errors/html/error_404.php';
        }

        $buffer = ob_get_contents();
        ob_end_clean();

        echo $buffer;
        $this->callExit(EXIT_UNKNOWN_FILE);    // Unknown file
    }

    //--------------------------------------------------------------------

    /**
     * Gathers the script output from the buffer, replaces some execution
     * time tag in the output and displays the debug toolbar, if required.
     *
     * @param null $cacheConfig
     * @param null $returned
     */
    protected function gatherOutput($cacheConfig = null, $returned = null)
    {
        $this->output = ob_get_contents();
        ob_end_clean();

        // If the controller returned a response object,
        // we need to grab the body from it so it can
        // be added to anything else that might have been
        // echoed already.
        // We also need to save the instance locally
        // so that any status code changes, etc, take place.
        if ($returned instanceof Response)
        {
            $this->response = $returned;
            $returned = $returned->getBody();
        }

        if (is_string($returned))
        {
            $this->output .= $returned;
        }

        // Cache it without the performance metrics replaced
        // so that we can have live speed updates along the way.
        if (self::$cacheTTL > 0)
        {
            $this->cachePage($cacheConfig);
        }

        $this->output = $this->displayPerformanceMetrics($this->output);

        $this->response->setBody($this->output);
    }

    //--------------------------------------------------------------------

    /**
     * If we have a session object to use, store the current URI
     * as the previous URI. This is called just prior to sending the
     * response to the client, and will make it available next request.
     *
     * This helps provider safer, more reliable previous_url() detection.
     *
     * @param \CodeIgniter\HTTP\URI $uri
     */
    public function storePreviousURL($uri)
    {
        // This is mainly needed during testing...
        if (is_string($uri))
        {
            $uri = new URI($uri);
        }

        if (isset($_SESSION))
        {
            $_SESSION['_ci_previous_url'] = (string)$uri;
        }
    }

    //--------------------------------------------------------------------

    /**
     * Sends the output of this request back to the client.
     * This is what they've been waiting for!
     */
    protected function sendResponse()
    {
        $this->response->send();
    }

    //--------------------------------------------------------------------

    /**
     * Exits the application, setting the exit code for CLI-based applications
     * that might be watching.
     *
     * Made into a separate method so that it can be mocked during testing
     * without actually stopping script execution.
     *
     * @param $code
     */
    protected function callExit($code)
    {
        exit($code);
    }

    //--------------------------------------------------------------------
}