const test = require('node:test');
const assert = require('node:assert/strict');
const fs = require('node:fs');

const source = fs.readFileSync('content/utils.js', 'utf8');

function extractFunction(name) {
  const start = source.indexOf(`function ${name}(`);
  if (start < 0) {
    throw new Error(`missing function ${name}`);
  }

  let parenDepth = 0;
  let signatureEnded = false;
  let braceStart = -1;
  for (let index = start; index < source.length; index += 1) {
    const ch = source[index];
    if (ch === '(') {
      parenDepth += 1;
    } else if (ch === ')') {
      parenDepth -= 1;
      if (parenDepth === 0) {
        signatureEnded = true;
      }
    } else if (ch === '{' && signatureEnded) {
      braceStart = index;
      break;
    }
  }

  if (braceStart < 0) {
    throw new Error(`missing body for function ${name}`);
  }

  let depth = 0;
  let end = braceStart;
  for (; end < source.length; end += 1) {
    const ch = source[end];
    if (ch === '{') depth += 1;
    if (ch === '}') {
      depth -= 1;
      if (depth === 0) {
        end += 1;
        break;
      }
    }
  }

  return source.slice(start, end);
}

test('detectScriptSource maps 126 mail hosts to the shared 163 mail source', () => {
  const bundle = [extractFunction('detectScriptSource')].join('\n');
  const api = new Function(`
${bundle}
return { detectScriptSource };
`)();

  assert.equal(
    api.detectScriptSource({
      url: 'https://mail.126.com/js6/main.jsp',
      hostname: 'mail.126.com',
    }),
    'mail-163'
  );
});