import { access, stat } from 'fs/promises';
import { resolve, dirname } from 'path';
import { fileURLToPath } from 'url';
import { execFile } from 'child_process';
import { promisify } from 'util';

const execFileAsync = promisify(execFile);
const __dir = dirname(fileURLToPath(import.meta.url));
const root = resolve(__dir, '..');
const pdfPath = resolve(root, 'output', 'cover.pdf');
const outPath = resolve(root, 'output', 'cover-300dpi.png');

try {
  await access(pdfPath);
} catch {
  console.error('output/cover.pdf not found — run `pnpm cover` first');
  process.exit(1);
}

console.log('Rendering cover to PNG at 300 DPI…');

await execFileAsync('gs', [
  '-dBATCH', '-dNOPAUSE', '-dQUIET',
  '-sDEVICE=png16m',
  '-r300',
  `-sOutputFile=${outPath}`,
  pdfPath,
]);

const { size } = await stat(outPath);
console.log(`Cover image: output/cover-300dpi.png  (${(size / 1_048_576).toFixed(1)} MB)`);