<?php

/**
 * JCH Optimize - Performs several front-end optimizations for fast downloads
 *
 * @package   jchoptimize/core
 * @author    Samuel Marshall <samuel@jch-optimize.net>
 * @copyright Copyright (c) 2022 Samuel Marshall / JCH Optimize
 * @license   GNU/GPLv3, or later. See LICENSE file
 *
 *  If LICENSE file missing, see <http://www.gnu.org/licenses/>.
 */

namespace JchOptimize\Core;

use _JchOptimizeVendor\V91\Joomla\Input\Input;
use _JchOptimizeVendor\V91\Psr\Http\Message\UriInterface;
use JchOptimize\Container\ContainerFactory;
use JchOptimize\Core\Platform\PathsInterface;
use JchOptimize\Core\Uri\Uri;
use JchOptimize\Core\Uri\UriNormalizer;
use JchOptimize\Core\Uri\Utils;

use function defined;
use function dirname;
use function ini_get;
use function is_null;
use function strpos;
use function strtolower;
use function substr_replace;
use function trim;

defined('_JCH_EXEC') or die('Restricted access');

/**
 * Class to provide info about the current request URI from the server
 */
class SystemUri
{
    /**
     * private instance of class
     *
     * @var ?SystemUri
     */
    private static ?SystemUri $instance = null;

    /**
     * Input object used internally
     *
     * @var Input
     */
    private Input $input;

    /**
     * The detected current url
     *
     * @var string
     */
    private string $requestUrl;

    /**
     * The detected current uri
     */
    private UriInterface $requestUri;
    /**
     * Path to index.php including host relative to the home page
     *
     * @var string
     */
    private string $currentBaseFull;

    /**
     * Path to index.php excluding the host relative to the home page
     *
     * @var string
     */
    private string $currentBasePath;

    /**
     * Constructor
     */
    private function __construct()
    {
        $this->input = new Input();

        $this->requestUrl = $this->detectRequestUri();

        $uri = Utils::uriFor($this->requestUrl);

        $requestUri = $this->input->server->getString('REQUEST_URI', '');

        // If we are working from a CGI SAPI with the 'cgi.fix_pathinfo' directive disabled we use PHP_SELF.
        if (str_contains(PHP_SAPI, 'cgi') && !ini_get('cgi.fix_pathinfo') && !empty($requestUri)) {
            // We aren't expecting PATH_INFO within PHP_SELF so this should work.
            $path = dirname($this->input->server->getString('PHP_SELF', ''));
        } else {
            // Pretty much everything else should be handled with SCRIPT_NAME.
            $path = dirname($this->input->server->getString('SCRIPT_NAME', ''));
        }

        //get the host from the URI
        $host = Uri::composeComponents($uri->getScheme(), $uri->getAuthority(), '', '', '');

        // Check if the path includes "index.php".
        if (str_contains($path, 'index.php')) {
            // Remove the index.php portion of the path.
            $path = substr_replace($path, '', strpos($path, 'index.php'), 9);
        }

        $path = Helper::removeTrailingSlash($path);

        $this->requestUri = UriNormalizer::systemUriNormalize($uri);

        $this->currentBaseFull = $host . $path . '/';
        $this->currentBasePath = $path . '/';
    }

    /**
     * Method to detect the requested URI from server environment variables.
     *
     * @return  string  The requested URI
     */
    private function detectRequestUri(): string
    {
        // First we need to detect the URI scheme.
        $scheme = $this->isSslConnection() ? 'https://' : 'http://';

        /*
         * There are some differences in the way that Apache and IIS populate server environment variables.  To
         * properly detect the requested URI we need to adjust our algorithm based on whether we are getting
         * information from Apache or IIS.
         */

        $phpSelf = $this->input->server->getString('PHP_SELF', '');
        $requestUri = $this->input->server->getString('REQUEST_URI', '');
        $host = $this->input->server->getString('HTTP_HOST');
        if (!$host) {
            $host = Utils::uriFor(ContainerFactory::getInstance()->get(PathsInterface::class)->liveSite())->getHost();
        }

        // If PHP_SELF and REQUEST_URI are both populated then we will assume "Apache Mode".
        if (!empty($phpSelf) && !empty($requestUri)) {
            // The URI is built from the HTTP_HOST and REQUEST_URI environment variables in an Apache environment.
            $uri = $scheme . $host . $requestUri;
        } else {
            // If not in "Apache Mode" we will assume that we are in an IIS environment and proceed.
            // IIS uses the SCRIPT_NAME variable instead of a REQUEST_URI variable... thanks, MS
            $uri = $scheme . $host . $this->input->server->getString('SCRIPT_NAME');
            $queryHost = $this->input->server->getString('QUERY_STRING', '');

            // If the QUERY_STRING variable exists append it to the URI string.
            if (!empty($queryHost)) {
                $uri .= '?' . $queryHost;
            }
        }

        return trim($uri);
    }

    /**
     * Determine if we are using a secure (SSL) connection.
     *
     * @return  bool  True if using SSL, false if not.
     *
     */
    private function isSslConnection(): bool
    {
        $serverSSLVar = $this->input->server->getString('HTTPS', '');

        if (!empty($serverSSLVar) && strtolower($serverSSLVar) !== 'off') {
            return true;
        }

        $serverForwarderProtoVar = $this->input->server->getString('HTTP_X_FORWARDED_PROTO', '');

        return !empty($serverForwarderProtoVar) && strtolower($serverForwarderProtoVar) === 'https';
    }

    /**
     * Static method to return the full request url
     *
     * @return string
     */
    public static function toString(): string
    {
        return self::getInstance()->requestUrl;
    }

    /**
     * Instance of class only used internally
     *
     * @return SystemUri
     */
    private static function getInstance(): SystemUri
    {
        if (is_null(self::$instance)) {
            self::$instance = new SystemUri();
        }

        return self::$instance;
    }

    /**
     * Static method to return current url of server (without query)
     *
     * @return string
     */
    public static function currentUrl(): string
    {
        $uri = new Uri(self::getInstance()->requestUrl);

        return Uri::composeComponents($uri->getScheme(), $uri->getAuthority(), $uri->getPath(), '', '');
    }

    public static function currentUri(): UriInterface
    {
        return self::getInstance()->requestUri;
    }

    /**
     * Static method to return path to home page script including the host
     *
     * @return string
     */
    public static function currentBaseFull(): string
    {
        return self::getInstance()->currentBaseFull;
    }

    /**
     * Static method to return path to home page script without the host
     *
     * @return string
     */
    public static function currentBasePath(): string
    {
        return self::getInstance()->currentBasePath;
    }

    /**
     * Returns path to home page including host
     */
    public static function homePageAbsolute(PathsInterface $pathsUtils): string
    {
        return Helper::appendTrailingSlash($pathsUtils->homeBaseFullPath());
    }

    /**
     * Returns path to home page excluding host
     */
    public static function homePagePathReference(PathsInterface $pathsUtils): string
    {
        return Helper::appendTrailingSlash($pathsUtils->homeBasePath());
    }

    /**
     * Used for Unit Testing
     *
     * @param UriInterface $uri
     * @return void
     * @todo Inject this class in container and use a Mock instead for testing
     */
    public static function setCurrentUri(UriInterface $uri): void
    {
        self::getInstance()->requestUri = $uri;
    }
}
