FMHY Base64 Auto Decoder

Decode base64-encoded links in some pastebins and make URLs clickable
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// ==UserScript==
// @name         FMHY Base64 Auto Decoder
// @namespace    http://tampermonkey.net/
// @version      3.2
// @description  Decode base64-encoded links in some pastebins and make URLs clickable
// @author       Mumukshu D.C
// @license      MIT
// @match        *://rentry.co/*
// @match        *://rentry.org/*
// @match        *://pastes.fmhy.net/*
// @match        *://bin.disroot.org/?*#*
// @match        *://privatebin.net/?*#*
// @match        *://textbin.xyz/?*#*
// @match        *://bin.idrix.fr/?*#*
// @match        *://privatebin.rinuploads.org/?*#*
// @match        *://pastebin.com/*
// @grant        none
// @icon         https://t1.gstatic.com/faviconV2?client=SOCIAL&type=FAVICON&fallback_opts=TYPE,SIZE,URL&url=http://fmhy.net&size=64
// ==/UserScript==

(function() {
    'use strict';

    const Utils = {
        isBase64(str) {
            return /^[A-Za-z0-9+/]+={0,2}$/.test(str);
        },
        decode(str) {
            try {
                return atob(str);
            } catch {
                return null;
            }
        },
        isUrl(str) {
            try {
                return ['http:', 'https:', 'ftp:'].includes(new URL(str).protocol);
            } catch {
                return false;
            }
        },
        escapeHTML(str) {
            return str.replace(/[&<>"']/g, m => ({
                '&': '&amp;',
                '<': '&lt;',
                '>': '&gt;',
                '"': '&quot;',
                "'": '&#039;'
            })[m]);
        },
        linkify(text, style = '', target = '_blank') {
            const escapedText = this.escapeHTML(text);
            const urlPattern = /(https?:\/\/[^\s]+)/g;
            return escapedText.replace(urlPattern, url =>
                `<a href="${url}" target="${target}" style="${style}">${url}</a>`
            );
        }
    };

    console.assert(Utils.isUrl('https://fmhy.net') && !Utils.isUrl('javascript:alert(1)'), 'URL validation failed');

    const HANDLERS = [
        {
            match: /^https:\/\/pastebin\.com\/.*/,
            selector: '.de1',
            process: (el) => {
                const text = el.textContent.trim();
                if (text.startsWith('aHR0')) {
                    const decoded = Utils.decode(text);
                    if (decoded) {
                        const originalColor = window.getComputedStyle(el).color;
                        el.innerHTML = Utils.linkify(decoded, `color: ${originalColor};`).replace(/\n/g, '<br>');
                    }
                }
            }
        },
        {
            match: /rentry\.(co|org)|pastes\.fmhy\.net/,
            selector: (url) => /^https:\/\/rentry\.(co|org)\/fmhybase64/i.test(url) ? 'code' : 'code, p',
            process: (el) => {
                const content = el.textContent.trim();
                if (Utils.isBase64(content)) {
                    const decoded = Utils.decode(content)?.trim();
                    if (!decoded) return;
                    const lines = decoded.split('\n');
                    if (!lines.some(line => Utils.isUrl(line.trim()))) return;
                    el.innerHTML = lines.map(line => {
                        const trimmed = line.trim();
                        if (!Utils.isUrl(trimmed)) return Utils.escapeHTML(line);
                        const escaped = Utils.escapeHTML(trimmed);
                        return `<a href="${escaped}">${escaped}</a>`;
                    }).join('<br>');
                }
            }
        },
        {
            match: /bin\.disroot\.org|privatebin\.net|textbin\.xyz|bin\.idrix\.fr|privatebin\.rinuploads\.org/,
            selector: '#prettyprint',
            process: (el) => {
                const content = el.innerText.trim();
                const lines = content.split('\n');
                let modified = false;
                const processedLines = lines.map(line => {
                    let target = line;
                    if (line.startsWith('`') && line.endsWith('`')) {
                        target = line.slice(1, -1);
                    }
                    if (Utils.isBase64(target)) {
                        const decoded = Utils.decode(target)?.trim();
                        if (decoded && Utils.isUrl(decoded)) {
                            modified = true;
                            const escaped = Utils.escapeHTML(decoded);
                            return `<a href="${escaped}">${escaped}</a>`;
                        }
                    }
                    return line;
                });
                if (modified) {
                    el.innerHTML = processedLines.join('\n');
                }
            }
        }
    ];

    const handler = HANDLERS.find(({ match }) => match.test(window.location.href));
    if (!handler) return;
    const processAll = () => {
        const selector = typeof handler.selector === 'function'
            ? handler.selector(window.location.href)
            : handler.selector;
        document.querySelectorAll(selector).forEach(handler.process);
    };
    new MutationObserver(processAll).observe(document.body, { childList: true, subtree: true });
    processAll();

})();