const input = document.getElementById('tool-input');
const output = document.getElementById('tool-output');
const logFilter = document.getElementById('log-filter');

function setOutput(value) {
  output.textContent = value;
}

function decodeBase64Url(value) {
  const normalized = value.replace(/-/g, '+').replace(/_/g, '/');
  const padded = normalized.padEnd(Math.ceil(normalized.length / 4) * 4, '=');
  return decodeURIComponent(atob(padded).split('').map((char) => `%${char.charCodeAt(0).toString(16).padStart(2, '0')}`).join(''));
}

document.getElementById('format-json').addEventListener('click', () => {
  try {
    setOutput(JSON.stringify(JSON.parse(input.value), null, 2));
  } catch (error) {
    setOutput(`JSON parse error: ${error.message}`);
  }
});

document.getElementById('decode-jwt').addEventListener('click', () => {
  try {
    const parts = input.value.trim().split('.');
    if (parts.length < 2) throw new Error('Expected header.payload.signature');
    setOutput(JSON.stringify({ header: JSON.parse(decodeBase64Url(parts[0])), payload: JSON.parse(decodeBase64Url(parts[1])) }, null, 2));
  } catch (error) {
    setOutput(`JWT decode error: ${error.message}`);
  }
});

document.getElementById('parse-url').addEventListener('click', () => {
  try {
    const url = new URL(input.value.trim());
    const params = {};
    url.searchParams.forEach((value, key) => { params[key] = value; });
    setOutput(JSON.stringify({ protocol: url.protocol, host: url.host, pathname: url.pathname, query: params, hash: url.hash }, null, 2));
  } catch (error) {
    setOutput(`URL parse error: ${error.message}`);
  }
});

document.getElementById('filter-logs').addEventListener('click', () => {
  const needle = logFilter.value.trim().toLowerCase();
  const lines = input.value.split('\n');
  const result = needle ? lines.filter((line) => line.toLowerCase().includes(needle)) : lines;
  setOutput(result.join('\n') || 'No matching lines.');
});