import { readFileSync, writeFileSync } from 'fs';
import { fileURLToPath } from 'url';
import { join, dirname } from 'path';

const __dirname = dirname(fileURLToPath(import.meta.url));
const foldsPath = join(__dirname, '../node_modules/folds/dist/index.js');
const foldsPkgPath = join(__dirname, '../node_modules/folds/package.json');

// Context lines around the target, not just the single `children: src(filled)`
// expression, so a coincidental match elsewhere in the bundle (e.g. some other
// `src(filled)` call) can't be mistaken for the Icon component we're patching.
// This is still string matching, not an AST edit, but the extra context makes
// an accidental match far less likely (Gitea #55).
const original = ['      ...props,', '      ref,', '      children: src(filled)', '    }'].join(
  '\n',
);
const patched = [
  '      ...props,',
  '      ref,',
  '      children: typeof src === "function" ? src(filled) : null',
  '    }',
].join('\n');

function foldsVersion() {
  try {
    return JSON.parse(readFileSync(foldsPkgPath, 'utf8')).version ?? 'unknown';
  } catch {
    return 'unknown';
  }
}

try {
  const content = readFileSync(foldsPath, 'utf8');

  if (content.includes(patched)) {
    // Already patched (e.g. re-running postinstall, or a fresh checkout that
    // already has a patched node_modules cache) — no-op, exit 0.
    console.log('folds patch already applied.');
  } else if (content.includes(original)) {
    writeFileSync(foldsPath, content.replace(original, patched), 'utf8');
    console.log('Applied defensive Icon src guard to folds.');
  } else {
    // Genuine "patch could not be applied" case: neither the original nor the
    // patched form was found, meaning folds changed the Icon implementation.
    // Fail loudly so the postinstall hook / CI breaks instead of silently
    // shipping an unpatched folds (which crashes at render with "src is not a
    // function"). See LOTUS_TODO.md "Dependencies / Build / Hygiene" for
    // context on why this is a direct node_modules patch rather than
    // patch-package.
    console.error('ERROR: folds Icon patch target not found.');
    console.error(`  folds version installed: ${foldsVersion()}`);
    console.error(`  Expected to find (surrounding context):\n${original}`);
    console.error(
      '  folds likely changed its Icon implementation. Update the patch target ' +
        'in scripts/patch-folds.mjs (see LOTUS_TODO -> "Dependencies / Build / Hygiene" ' +
        '-> patch-folds.mjs entry) before building.',
    );
    process.exit(1);
  }
} catch (e) {
  console.error('ERROR: Could not patch folds:', e.message);
  process.exit(1);
}