<?php
/**
 * Syntax based normalization of URI's
 *
 * This normalises URI's based on the specification RFC 3986
 * www . apps . ietf . org/rfc/rfc3986.html
 *
 * Example usage:
 * <code>
 * require_once 'PageCacheURLNormalizer.php';
 *
 * $url = 'eXAMPLE://a/./b/../b/%63/%7bfoo%7d';
 * $un = new PageCacheURLNormalizer();
 * $un->setUrl( $url );
 * echo $un->normalize();
 *
 * // result: "example://a/b/c/%7Bfoo%7D"
 * </code>
 *
 *    @author    Glen Scott <glen_scott @ yahoo.co.uk>
 *    @copyright Glen Scott
 *    @license   Open Source
 */

if (!defined('_PS_VERSION_')) {exit;}

// Check existence of the class to be able to handle compatibility problems in a friendly way
if (!class_exists('PageCacheURLNormalizer')) {

    if (!function_exists('pagecacheRawurlencode')) {
        function pagecacheRawurlencode($value)
        {
            if (is_array($value)) {
                return array_map('pagecacheRawurlencode', array_values($value));
            } else {
                return rawurldecode($value);
            }
        }
    }

    class PageCacheURLNormalizer
    {
        private $url;
        private $scheme;
        private $host;
        private $port;
        private $user;
        private $pass;
        private $path;
        private $query;
        private $fragment;
        private $default_scheme_ports = array('http:' => 80, 'https:' => 443,);
        private $components = array('scheme', 'host', 'port', 'user', 'pass', 'path', 'query', 'fragment',);

        public function __construct($url = null)
        {
            if ($url) {
                $this->setUrl($url);
            }
        }

        public function getUrl()
        {
            return $this->url;
        }

        public function setUrl($url)
        {
            $this->url = $url;

            // parse URL into respective parts
            $url_components = parse_url($this->url);

            if (!$url_components) {
                // Reset URL
                $this->url = '';

                // Flush properties
                foreach ($this->components as $key) {
                    if (property_exists($this, $key)) {
                        $this->$key = '';
                    }
                }

                return false;
            } else {
                // Update properties
                foreach ($url_components as $key => $value) {
                    if (property_exists($this, $key)) {
                        $this->$key = $value;
                    }
                }

                // Flush missing components
                $missing_components = array_diff(
                    array_values($this->components),
                    array_keys($url_components)
                );

                foreach ($missing_components as $key) {
                    if (property_exists($this, $key)) {
                        $this->$key = '';
                    }
                }

                return true;
            }
        }

        public function normalize()
        {

            // URI Syntax Components
            // scheme authority path query fragment
            // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3

            // Scheme
            // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.1

            if ($this->scheme) {
                // Converting the scheme to lower case
                $this->scheme = Tools::strtolower($this->scheme) . ':';
            }

            // Authority
            // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.2

            $authority = '';
            if ($this->host) {
                $authority .= '//';

                // User Information
                // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.2.1

                if ($this->user) {
                    if ($this->pass) {
                        $authority .= $this->user . ':' . $this->pass . '@';
                    } else {
                        $authority .= $this->user . '@';
                    }
                }

                // Host
                // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.2.2

                // Converting the host to lower case
                $authority .= Tools::strtolower($this->host);

                // Port
                // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.2.3

                // Removing the default port
                if (isset($this->default_scheme_ports[$this->scheme])
                    && $this->port == $this->default_scheme_ports[$this->scheme]) {
                    $this->port = '';
                }

                if ($this->port) {
                    $authority .= ':' . $this->port;
                }
            }

            // Path
            // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.3

            if ($this->path) {
                // Removing dot-segments
                $this->path = $this->removeDotSegments($this->path);

                // Do not urlDecodeUnreservedChars to preserve Greek URLs for exemple
                //$this->path = $this->urlDecodeUnreservedChars( $this->path );

                $this->path = $this->urlDecodeReservedSubDelimChars($this->path);
            } // Add default path only when valid URL is present
            elseif ($this->url) {
                // Adding trailing /
                $this->path = '/';
            }

            // Query
            // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.4

            if ($this->query) {
                parse_str($this->query, $query);

                $keys = array_map('rawurldecode', array_keys($query));
                $values = array_map('pagecacheRawurlencode', array_values($query));
                $query = array_combine($keys, $values);

                $this->query = '?' . str_replace('+', '%20', http_build_query($query, '', '&'));

                // Fix http_build_query adding equals sign to empty keys
                $this->query = str_replace('=&', '&', rtrim($this->query, '='));
            }

            // Fragment
            // @link www.apps.ietf . org/rfc/rfc3986.html#sec-3.5

            if ($this->fragment) {
                $this->fragment = rawurldecode($this->fragment);
                $this->fragment = rawurlencode($this->fragment);
                $this->fragment = '#' . $this->fragment;
            }

            $this->setUrl($this->scheme . $authority . $this->path . $this->query . $this->fragment);

            return $this->getUrl();
        }

        /**
         * Path segment normalization
         * www.apps.ietf . org/rfc/rfc3986.html#sec-5.2.4
         */
        public function removeDotSegments($path)
        {
            $new_path = '';

            while (!empty($path)) {
                // A
                $pattern_a = '!^(\.\./|\./)!x';
                $pattern_b_1 = '!^(/\./)!x';
                $pattern_b_2 = '!^(/\.)$!x';
                $pattern_c = '!^(/\.\./|/\.\.)!x';
                $pattern_d = '!^(\.|\.\.)$!x';
                $pattern_e = '!(/*[^/]*)!x';

                if (preg_match($pattern_a, $path)) {
                    // remove prefix from $path
                    $path = preg_replace($pattern_a, '', $path);
                } elseif (preg_match($pattern_b_1, $path, $matches) || preg_match($pattern_b_2, $path, $matches)) {
                    $path = preg_replace("!^" . $matches[1] . "!", '/', $path);
                } elseif (preg_match($pattern_c, $path, $matches)) {
                    $path = preg_replace('!^' . preg_quote($matches[1], '!') . '!x', '/', $path);

                    // remove the last segment and its preceding "/" (if any) from output buffer
                    $new_path = preg_replace('!/([^/]+)$!x', '', $new_path);
                } elseif (preg_match($pattern_d, $path)) {
                    $path = preg_replace($pattern_d, '', $path);
                } else {
                    if (preg_match($pattern_e, $path, $matches)) {
                        $first_path_segment = $matches[1];

                        $path = preg_replace('/^' . preg_quote($first_path_segment, '/') . '/', '', $path, 1);

                        $new_path .= $first_path_segment;
                    }
                }
            }

            return $new_path;
        }

        public function getScheme()
        {
            return $this->scheme;
        }

        /**
         * Decode unreserved characters
         *
         * @link www.apps.ietf . org/rfc/rfc3986.html#sec-2.3
         */
        public function urlDecodeUnreservedChars($string)
        {
            $string = rawurldecode($string);
            $string = rawurlencode($string);
            $string = str_replace(array('%2F', '%3A', '%40'), array('/', ':', '@'), $string);

            return $string;
        }

        /**
         * Decode reserved sub-delims
         *
         * @link www.apps.ietf . org/rfc/rfc3986.html#sec-2.2
         */
        public function urlDecodeReservedSubDelimChars($string)
        {
            return str_replace(array('%21', '%24', '%26', '%27', '%28', '%29', '%2A', '%2B', '%2C', '%3B', '%3D'),
                array('!', '$', '&', "'", '(', ')', '*', '+', ',', ';', '='), $string);
        }
    }
}