<?php

/**
 * Provides static methods for cleansing user input before storing in the database.
 *
 * @package NamelessMC\Core
 * @author Samerton
 * @version 2.0.0-pr8
 * @license MIT
 */
class Output
{
    /**
     * @var HTMLPurifier Static purifier instance.
     */
    private static HTMLPurifier $_purifier;

    /**
     * Returns a clean version of an inputted string.
     * Will remove HTML, convert HTML entities, and strip slashes.
     *
     * @param  ?string $input The string which will be cleaned
     * @return ?string Cleaned version of string.
     */
    public static function getClean(?string $input): ?string
    {
        return $input === null ? null : htmlspecialchars($input, ENT_QUOTES);
    }

    /**
     * Returns a decoded version of a clean string.
     *
     * @param  ?string $input Contains the clean string which will be decoded.
     * @return ?string Decoded string.
     */
    public static function getDecoded(?string $input): ?string
    {
        return $input === null ? null : htmlspecialchars_decode($input, ENT_QUOTES);
    }

    /**
     * Returns a purified version of an inputted string with HTMLPurifier.
     * Will not remove any HTML tags.
     *
     * @param string|null $input          String which will be purified.
     * @param bool        $escape_invalid Should invalid HTML be escaped instead of fully removed?
     * @param bool        $for_editor     Whether the purification is for use in the WYSIWYG editor or not, default true
     *
     * @return string Purified string.
     */
    public static function getPurified(?string $input, bool $escape_invalid = false, bool $for_editor = true): string
    {
        if (!isset(self::$_purifier)) {
            $purifierConfig = HTMLPurifier_Config::createDefault();

            // Config settings
            $purifierConfig->set('HTML.Doctype', 'XHTML 1.0 Transitional');
            $purifierConfig->set('URI.DisableExternalResources', false);
            $purifierConfig->set('URI.DisableResources', false);
            $purifierConfig->set('HTML.Allowed', 'u,a,p,p[style],b,i,small,blockquote,span[style],span[class],p,strong,em,li,ul,ol,div[align],br,img,figure,figcaption');
            $purifierConfig->set('CSS.AllowedProperties', ['text-align', 'display', 'float', 'color', 'background-color', 'background', 'font-size', 'font-family', 'margin', 'margin-bottom', 'margin-left', 'margin-right', 'margin-top', 'padding', 'padding-bottom', 'padding-left', 'padding-right', 'padding-top', 'text-decoration', 'font-weight', 'font-style', 'font-size', 'vertical-align', 'width', 'border-color', 'border-style']);
            $purifierConfig->set('CSS.AllowTricky', true);
            $purifierConfig->set('HTML.AllowedAttributes', 'target, rel, href, id, src, height, width, alt, class, *.style, dir');
            $purifierConfig->set('HTML.ForbiddenAttributes', 'iframe@width,iframe@height');
            $purifierConfig->set('Attr.AllowedFrameTargets', ['_blank', '_self', '_parent', '_top']);
            $purifierConfig->set('Attr.AllowedRel', ['noopener', 'nofollow']);
            $purifierConfig->set('HTML.SafeIframe', true);
            $purifierConfig->set('URI.SafeIframeRegexp', '%^(https?:)?//(www\.youtube(?:-nocookie)?\.com/embed/|player\.vimeo\.com/video/)%');
            $purifierConfig->set('Core.EscapeInvalidTags', $escape_invalid);
            $purifierConfig->set('AutoFormat.Linkify', true);

            $purifierConfig->set('HTML.DefinitionID', 'namelessmc');
            $purifierConfig->set('HTML.DefinitionRev', 1);
            $purifierConfig->set('Cache.DefinitionImpl', null);

            if ($def = $purifierConfig->maybeGetRawHTMLDefinition()) {
                $def->addElement('figure', 'Block', 'Optional: (figcaption, Flow) | (Flow, figcaption) | Flow', 'Common');
                $def->addElement('figcaption', 'Inline', 'Flow', 'Common');
            }

            self::$_purifier = new HTMLPurifier($purifierConfig);
        }

        $purified = self::$_purifier->purify($input);

        if ($for_editor) {
            // Double encode &lt; and &gt; to prevent editor from parsing them
            return str_replace(['&lt;', '&gt;'], ['&amp;lt;', '&amp;gt;'], $purified);
        }

        return $purified;
    }

    /**
     * urlencode() a string without encoding slashes.
     *
     * @param  string $input String to encode
     * @return string Encoded string
     */
    public static function urlEncodeAllowSlashes(string $input): string
    {
        return str_replace('%2F', '/', urlencode($input));
    }
}