/**
 * Tailwind v3 config for building a PURGED CSS bundle for Easy Invoice.
 *
 * Why this exists:
 *   - The shipped tailwind.min.css is 2.8 MB (full CDN dump, no purge).
 *   - Only ~572 utility classes are actually used across all templates +
 *     addons + admin chrome. A purged build is ~40-90 KB.
 *   - That's a 30-90× reduction on every admin page load, which is the
 *     single largest performance win in the perf audit.
 *
 * Behavior is opt-in. The build outputs `tailwind.purged.min.css` next to
 * the existing `tailwind.min.css` — the admin enqueue keeps using the
 * original until a future PR adds the switch. Verify visually on a few
 * representative pages (Dashboard, Invoice Builder, Addons grid, every
 * addon settings page, Settings, Reports) before enabling the swap.
 *
 * Build steps (requires Node 18+ and npm):
 *
 *   cd tools/tailwind-build
 *   npm install
 *   npm run build
 *
 * Output: ../../assets/lib/tailwind/tailwind.purged.min.css
 */
module.exports = {
  // The `content` array tells Tailwind which files to scan for class names.
  // Anything matched anywhere in these files (PHP, JS, HTML, any string
  // literal containing what looks like a class name) gets kept.
  //
  // Paths are relative to this config file (tools/tailwind-build/).
  // The pro plugin lives in a sibling dir, so we use ../../../ to reach it.
  content: [
    '../../templates/**/*.php',
    '../../includes/**/*.php',
    '../../assets/js/**/*.js',
    '../../../easy-invoice-pro/includes/**/*.php',
    '../../../easy-invoice-pro/addons/**/*.php',
    '../../../easy-invoice-pro/assets/js/**/*.js',
  ],

  // Safelist: classes we KNOW are used but Tailwind's scanner might miss
  // (dynamically composed in JS, built via string concat, etc.). The
  // ./safelist.txt file is generated by scanning every class= attribute
  // across the codebase — read it at build time.
  safelist: (function () {
    const fs = require('fs');
    const path = require('path');
    const file = path.join(__dirname, 'safelist.txt');
    if (!fs.existsSync(file)) return [];
    return fs.readFileSync(file, 'utf-8')
      .split(/\r?\n/)
      .map(s => s.trim())
      .filter(Boolean);
  })(),

  theme: {
    extend: {},
  },
  // No plugins by default — the codebase uses only stock utilities.
  // Add @tailwindcss/forms, @tailwindcss/typography etc. here if templates
  // start using their classes.
  plugins: [],
};