dev.js

const { spawn } = require('child_process');
const fs = require('fs');
const path = require('path');

const WATCH_DIRS = ['css', 'js'];
const WATCH_FILES = ['index.html'];
const DEBOUNCE_MS = 300;

let buildTimer = null;
let building = false;

function rebuild() {
  if (building) {
    buildTimer = setTimeout(rebuild, DEBOUNCE_MS);
    return;
  }
  building = true;
  console.log(`\n[${new Date().toLocaleTimeString()}] Rebuilding...`);
  const child = spawn('node', ['build.js'], { stdio: 'inherit' });
  child.on('close', (code) => {
    building = false;
    if (code === 0) console.log('Ready.');
    else console.log(`Build exited with code ${code}`);
  });
}

function scheduleRebuild(label) {
  console.log(`[watch] Changed: ${label}`);
  clearTimeout(buildTimer);
  buildTimer = setTimeout(rebuild, DEBOUNCE_MS);
}

// Watch individual files
for (const file of WATCH_FILES) {
  if (fs.existsSync(file)) {
    fs.watch(file, () => scheduleRebuild(file));
  }
}

// Watch directories recursively
for (const dir of WATCH_DIRS) {
  if (fs.existsSync(dir)) {
    fs.watch(dir, { recursive: true }, (_event, filename) => {
      scheduleRebuild(path.join(dir, filename || ''));
    });
  }
}

console.log(`Watching: ${WATCH_FILES.join(', ')}, ${WATCH_DIRS.join('/, ')}/ for changes`);

// Initial build
rebuild();

// Start http-server on docs/
const server = spawn('npx', ['http-server', 'docs', '-p', '8080', '-c-1'], {
  stdio: 'inherit',
});

process.on('SIGINT', () => {
  server.kill();
  process.exit();
});