/**
 * Build script: copy src → dist, minify JS/CSS, inline critical CSS (Beasties).
 * Run with: pnpm build
 */
import {
    rmSync,
    mkdirSync,
    readFileSync,
    writeFileSync,
    cpSync,
    readdirSync,
} from 'fs';
import { join, dirname, extname } from 'path';
import { fileURLToPath } from 'url';
import Beasties from 'beasties';
import { minify as minifyJs } from 'terser';
import CleanCSS from 'clean-css';

const __dirname = dirname(fileURLToPath(import.meta.url));
const root = join(__dirname, '..');
const srcDir = join(root, 'src');
const distDir = join(root, 'dist');

function getFiles(dir, files = []) {
    const entries = readdirSync(dir, { withFileTypes: true });
    for (const e of entries) {
        const full = join(dir, e.name);
        if (e.isDirectory()) getFiles(full, files);
        else files.push(full);
    }
    return files;
}

async function main() {
    // 1. Clean and copy src → dist
    rmSync(distDir, { recursive: true, force: true });
    mkdirSync(distDir, { recursive: true });
    cpSync(srcDir, distDir, { recursive: true });

    const distFiles = getFiles(distDir);

    // 2. Minify JS
    const jsFiles = distFiles.filter((f) => extname(f) === '.js');
    for (const f of jsFiles) {
        const code = readFileSync(f, 'utf8');
        const result = await minifyJs(code, { format: { comments: false } });
        if (result.code) writeFileSync(f, result.code);
    }

    // 3. Minify CSS
    const cleanCss = new CleanCSS({ level: 2 });
    const cssFiles = distFiles.filter((f) => extname(f) === '.css');
    for (const f of cssFiles) {
        const code = readFileSync(f, 'utf8');
        const result = cleanCss.minify(code);
        if (!result.errors.length) writeFileSync(f, result.styles);
    }

    // 4. Inline critical CSS with Beasties for all HTML files (no browser; works in CI)
    const htmlFiles = distFiles.filter((f) => extname(f) === '.html');
    const beasties = new Beasties({
        path: distDir,
        preload: 'default',
        logLevel: 'warn',
    });
    for (const htmlFile of htmlFiles) {
        const html = readFileSync(htmlFile, 'utf8');
        const inlined = await beasties.process(html);
        writeFileSync(htmlFile, inlined);
    }

    console.log('Build complete: dist/');
}

main().catch((err) => {
    console.error(err);
    process.exit(1);
});