Build a Production-Ready HTML Beautifier (Custom Regex Engine)

const nodes = html.split(/>\s*</);

const VOID_TAGS = ['area', 'base', 'br', 'col', 'embed', 'hr', 'img', 'input', 'link', 'meta', 'param', 'source', 'track', 'wbr'];

const isVoid = (tagName) => VOID_TAGS.includes(tagName);

'use client';
import { useState } from 'react';
import { Copy, Download, Trash2, FileCode } from 'lucide-react';

export default function ProductionBeautifier() {
  const [input, setInput] = useState('');
  const [output, setOutput] = useState('');
  const [mode, setMode] = useState('beautify'); // 'beautify' | 'minify'
  const [indentSize, setIndentSize] = useState(2);
  const [stripComments, setStripComments] = useState(false);

  // --- CORE LOGIC START ---
  const processHTML = () => {
    if (!input.trim()) return;

    let code = input;

    // 1. Pre-processing (Comments)
    if (stripComments) {
      code = code.replace(/<!--[\s\S]*?-->/g, '');
    }

    // 2. Minification Path
    if (mode === 'minify') {
      const minified = code
        .replace(/\s+/g, ' ')       // Collapse whitespace
        .replace(/>\s+</g, '><')    // Remove tag gaps
        .trim();
      setOutput(minified);
      return;
    }

    // 3. Beautification Path
    let formatted = '';
    let indent = 0;
    const tab = ' '.repeat(indentSize);

    code.split(/>\s*</).forEach(node => {
        // Decrease indent for closing tags (e.g. /div)
        if (node.match(/^\/\w/)) indent--;
        
        // Prevent negative indent crash
        const level = Math.max(0, indent);
        
        // Reconstruct tag with padding
        formatted += tab.repeat(level) + '<' + node + '>\n';
        
        // Increase indent for opening tags (that are NOT void/self-closing)
        // Regex checks: Starts with char, doesn't end with /
        if (node.match(/^<?\w[^>]*[^/]$/)) {
            // Check against list of known void tags
            const tagName = node.match(/^<?(\w+)/)[1].toLowerCase();
            const voidTags = ['img','input','br','hr','meta','link','base'];
            
            if (!voidTags.includes(tagName)) {
                indent++;
            }
        }
    });

    // Cleanup first/last lines from split artifacts
    setOutput(formatted.substring(1, formatted.length - 2));
  };
  // --- CORE LOGIC END ---

  // UI Helpers
  const copy = () => navigator.clipboard.writeText(output);
  const clear = () => { setInput(''); setOutput(''); };

  return (
    <div className="max-w-4xl mx-auto p-6 space-y-6 bg-slate-50 border rounded-xl">
      <div className="flex justify-between items-center">
        <h2 className="text-2xl font-bold flex gap-2 items-center text-slate-800">
           <FileCode className="text-blue-600"/> HTML Engine
        </h2>
        
        {/* Controls */}
        <div className="flex gap-2">
           <select 
             className="p-2 rounded border bg-white text-sm"
             value={mode} onChange={e => setMode(e.target.value)}
           >
             <option value="beautify">Beautify Mode</option>
             <option value="minify">Minify Mode</option>
           </select>
           
           <select 
             className="p-2 rounded border bg-white text-sm"
             value={indentSize} onChange={e => setIndentSize(Number(e.target.value))}
             disabled={mode === 'minify'}
           >
             <option value={2}>2 Spaces</option>
             <option value={4}>4 Spaces</option>
           </select>
           
           <button 
             onClick={() => setStripComments(!stripComments)}
             className={`p-2 rounded border text-sm ${stripComments ? 'bg-red-100 text-red-700 border-red-200' : 'bg-white'}`}
           >
             {stripComments ? 'No Comments' : 'Keep Comments'}
           </button>
        </div>
      </div>

      <div className="grid md:grid-cols-2 gap-4">
        {/* Input */}
        <div className="space-y-2">
            <div className="flex justify-between text-xs font-bold text-slate-500 uppercase">
                <span>Input HTML</span>
                <button onClick={clear} className="text-red-500 hover:text-red-700 flex gap-1 items-center">
                    <Trash2 size={12}/> Clear
                </button>
            </div>
            <textarea 
                className="w-full h-80 p-4 rounded-lg border border-slate-300 font-mono text-xs focus:ring-2 focus:ring-blue-500 outline-none"
                placeholder="Paste messy code..."
                value={input}
                onChange={e => setInput(e.target.value)}
            />
        </div>

        {/* Output */}
        <div className="space-y-2">
            <div className="flex justify-between text-xs font-bold text-slate-500 uppercase">
                <span>Result</span>
                <button onClick={copy} className="text-blue-600 hover:text-blue-800 flex gap-1 items-center">
                    <Copy size={12}/> Copy
                </button>
            </div>
            <textarea 
                className="w-full h-80 p-4 rounded-lg border border-slate-300 bg-slate-900 text-green-400 font-mono text-xs"
                readOnly
                value={output}
                placeholder="Clean code appears here..."
            />
        </div>
      </div>

      <button 
        onClick={processHTML}
        className="w-full py-4 bg-gradient-to-r from-blue-600 to-indigo-600 text-white font-bold rounded-lg hover:shadow-lg transition transform hover:-translate-y-0.5"
      >
        {mode === 'beautify' ? '✨ Beautify HTML' : '📦 Minify HTML'}
      </button>
    </div>
  );
}