#!/usr/bin/env node
/*
 * Lightweight backend lint gate: syntax-check all backend JS files.
 */

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

const ROOT = path.resolve(__dirname, '..');
const BACKEND_DIR = path.join(ROOT, 'backend');
const IGNORED_DIRS = new Set([
  'node_modules',
  'coverage',
  'frontend',
  'build',
  'test-results',
  'uploads',
  '.pm2',
  '__pycache__'
]);

function walk(dir, out = []) {
  const entries = fs.readdirSync(dir, { withFileTypes: true });

  for (const entry of entries) {
    const fullPath = path.join(dir, entry.name);

    if (entry.isDirectory()) {
      if (IGNORED_DIRS.has(entry.name)) continue;
      walk(fullPath, out);
      continue;
    }

    if (entry.isFile() && entry.name.endsWith('.js')) {
      out.push(fullPath);
    }
  }

  return out;
}

function checkFile(filePath) {
  const result = spawnSync(process.execPath, ['--check', filePath], {
    encoding: 'utf8'
  });

  return {
    filePath,
    ok: result.status === 0,
    stdout: result.stdout,
    stderr: result.stderr,
    status: result.status
  };
}

function main() {
  const files = walk(BACKEND_DIR).sort();

  if (files.length === 0) {
    console.error('No backend JS files found to lint.');
    process.exit(2);
  }

  const failures = files
    .map(checkFile)
    .filter((result) => !result.ok);

  console.log(`Checked ${files.length} backend JS files.`);

  if (failures.length > 0) {
    console.error(`Syntax lint failed for ${failures.length} file(s):`);
    failures.forEach((failure) => {
      console.error(`\n--- ${path.relative(ROOT, failure.filePath)} ---`);
      const output = (failure.stderr || failure.stdout || '').trim();
      if (output) {
        console.error(output);
      }
    });
    process.exit(1);
  }

  console.log('Backend syntax lint passed.');
}

main();