fiddle/public/js/app.js

import {
  initEditors, switchMode, getEditorValues, setEditorValues,
  setOnChange, getCurrentMode, getCssType, setCssType,
  relayoutEditors,
  MODE_TABS, MODE_TO_JS_TYPE, JS_TYPE_TO_MODE,
} from './editors.js';
import { renderPreview } from './preview.js';
import { initConsole, clearConsole } from './console-panel.js';
import { compileCss } from './preprocessors.js';
import { compileJs } from './js-preprocessors.js';
import { createFiddle, loadFiddle, updateFiddle } from './api.js';
import { getPref, setPref } from './preferences.js';
import { initEmmet } from './emmet.js';
import { initKeybindings } from './keybindings.js';
import { initResizer, clearInlineSizes } from './resizer.js';

let currentId = null;
let debounceTimer = null;

const $ = (sel) => document.querySelector(sel);

const STARTER_TEMPLATES = {
  'html-css-js': { html: '', css: '', js: '' },
  'typescript': {
    html: '<div id="app"></div>',
    css: '',
    js: `interface Greeting {\n  name: string;\n  message: string;\n}\n\nconst greet = (g: Greeting): string => \`\${g.message}, \${g.name}!\`;\n\nconst result = greet({ name: "World", message: "Hello" });\ndocument.getElementById("app")!.innerHTML = \`<h1>\${result}</h1>\`;\nconsole.log(result);`,
  },
  'react': {
    js: `const App = () => {\n  const [count, setCount] = React.useState(0);\n  return (\n    <div>\n      <h1>Hello React</h1>\n      <button onClick={() => setCount(c => c + 1)}>Count: {count}</button>\n    </div>\n  );\n};\n\nReactDOM.createRoot(document.getElementById('root')).render(<App />);`,
    css: '',
    html: '',
  },
  'react-ts': {
    js: `const App: React.FC = () => {\n  const [count, setCount] = React.useState<number>(0);\n  return (\n    <div>\n      <h1>Hello React + TypeScript</h1>\n      <button onClick={() => setCount(c => c + 1)}>Count: {count}</button>\n    </div>\n  );\n};\n\nReactDOM.createRoot(document.getElementById('root')!).render(<App />);`,
    css: '',
    html: '',
  },
  'vue': {
    js: `<template>\n  <div>\n    <h1>{{ msg }}</h1>\n    <button @click="count++">Count: {{ count }}</button>\n  </div>\n</template>\n\n<script>\nconst component = {\n  data() {\n    return {\n      msg: 'Hello Vue!',\n      count: 0,\n    };\n  },\n};\n</script>`,
    css: '',
  },
  'svelte': {
    js: `<script>\n  let count = 0;\n</script>\n\n<h1>Hello Svelte</h1>\n<button on:click={() => count++}>Count: {count}</button>\n\n<style>\n  h1 { color: #ff3e00; }\n  button { padding: 8px 16px; cursor: pointer; }\n</style>`,
    css: '',
  },
};

async function run() {
  const mode = getCurrentMode();
  const { html, css, js } = getEditorValues();
  const cssType = getCssType();

  try {
    const compiledCss = await compileCss(css, cssType);
    const result = await compileJs(js, mode);
    clearConsole();

    // Show warnings from compilation (e.g., Svelte)
    if (result.warnings && result.warnings.length) {
      result.warnings.forEach((w) => {
        window.postMessage({ type: 'console', method: 'warn', args: [w] }, '*');
      });
    }

    renderPreview(html, compiledCss, result.js, mode, result.extraCss || '');
  } catch (e) {
    clearConsole();
    renderPreview(html, '', '', mode);
    window.postMessage({ type: 'console', method: 'error', args: [`Compile error: ${e.message}`] }, '*');
  }
}

function scheduleRun() {
  if (!getPref('autoRun')) return;
  clearTimeout(debounceTimer);
  debounceTimer = setTimeout(run, 500);
}

function showToast(msg) {
  const toast = $('#share-toast');
  toast.textContent = msg;
  toast.classList.remove('hidden');
  setTimeout(() => toast.classList.add('hidden'), 3000);
}

async function save() {
  const { html, css, js } = getEditorValues();
  const title = $('#title-input').value || 'Untitled';
  const css_type = getCssType();
  const js_type = MODE_TO_JS_TYPE[getCurrentMode()] || 'javascript';
  try {
    if (currentId) {
      await updateFiddle(currentId, { title, html, css, css_type, js, js_type });
      showToast(`Saved! Share: ${location.origin}/f/${currentId}`);
    } else {
      const result = await createFiddle({ title, html, css, css_type, js, js_type });
      currentId = result.id;
      history.pushState(null, '', `/f/${currentId}`);
      showToast(`Saved! Share: ${location.origin}/f/${currentId}`);
    }
  } catch (e) {
    showToast(`Save failed: ${e.message}`);
  }
}

async function fork() {
  const { html, css, js } = getEditorValues();
  const title = ($('#title-input').value || 'Untitled') + ' (fork)';
  const css_type = getCssType();
  const js_type = MODE_TO_JS_TYPE[getCurrentMode()] || 'javascript';
  try {
    const result = await createFiddle({ title, html, css, css_type, js, js_type });
    currentId = result.id;
    $('#title-input').value = title;
    history.pushState(null, '', `/f/${currentId}`);
    showToast(`Forked! New URL: ${location.origin}/f/${currentId}`);
  } catch (e) {
    showToast(`Fork failed: ${e.message}`);
  }
}

async function loadFromUrl() {
  const match = location.pathname.match(/^\/f\/([a-zA-Z0-9_-]+)$/);
  if (!match) return;
  try {
    const fiddle = await loadFiddle(match[1]);
    currentId = fiddle.id;
    $('#title-input').value = fiddle.title;

    // Restore mode from js_type
    const mode = JS_TYPE_TO_MODE[fiddle.js_type] || 'html-css-js';
    $('#framework-mode').value = mode;
    switchMode(mode);

    // Restore CSS type
    setCssType(fiddle.css_type || 'css');

    setEditorValues(fiddle);
    setTimeout(run, 100);
  } catch (e) {
    showToast(`Failed to load fiddle: ${e.message}`);
  }
}

function handleModeChange(newMode) {
  const oldMode = getCurrentMode();
  if (newMode === oldMode) return;

  switchMode(newMode);

  // Insert starter template if editors are empty
  const { html, css, js } = getEditorValues();
  if (!html && !css && !js) {
    const template = STARTER_TEMPLATES[newMode];
    if (template) {
      setEditorValues(template);
    }
  }

  scheduleRun();
}

function applyLayout(layout) {
  const grid = $('.grid');
  // Remove all layout classes
  grid.classList.remove('layout-top-bottom', 'layout-editor-only', 'layout-preview-only');
  // Clear resizer inline styles when switching layouts
  clearInlineSizes();

  if (layout === 'top-bottom') grid.classList.add('layout-top-bottom');
  else if (layout === 'editor-only') grid.classList.add('layout-editor-only');
  else if (layout === 'preview-only') grid.classList.add('layout-preview-only');

  setPref('layout', layout);
  // Give DOM time to reflow then relayout editors
  requestAnimationFrame(() => relayoutEditors());
}

async function init() {
  // Load Emmet before editors so completion providers are registered
  await initEmmet();

  initEditors('html-css-js');
  setOnChange(scheduleRun);
  initConsole();
  initResizer();
  initKeybindings();

  // Auto-run checkbox
  const autoRunCb = $('#auto-run-checkbox');
  autoRunCb.checked = getPref('autoRun');
  autoRunCb.addEventListener('change', (e) => setPref('autoRun', e.target.checked));

  // Layout selector
  const layoutSel = $('#layout-mode');
  const savedLayout = getPref('layout') || 'default';
  layoutSel.value = savedLayout;
  if (savedLayout !== 'default') applyLayout(savedLayout);
  layoutSel.addEventListener('change', (e) => applyLayout(e.target.value));

  // Mode selector
  $('#framework-mode').addEventListener('change', (e) => {
    handleModeChange(e.target.value);
  });

  // Toolbar buttons
  $('#btn-run').addEventListener('click', run);
  $('#btn-save').addEventListener('click', save);
  $('#btn-fork').addEventListener('click', fork);

  // Keyboard shortcuts
  document.addEventListener('keydown', (e) => {
    if ((e.ctrlKey || e.metaKey) && e.key === 's') {
      e.preventDefault();
      save();
    }
    if ((e.ctrlKey || e.metaKey) && e.key === 'Enter') {
      e.preventDefault();
      run();
    }
  });

  // Load fiddle from URL if present
  loadFromUrl();

  // Handle browser back/forward
  window.addEventListener('popstate', () => {
    currentId = null;
    loadFromUrl();
  });
}

init();