/**
 * UI Rendering Module for Visualization UI
 * Handles rendering of Alerts table and Outlier summary panel.
 *
 * @module ui
 */

/**
 * Renders the Max-only alert data into a table structure within #alert-dashboard.
 * @param {Array<Object>} alerts - Array of alert objects from /alert-data endpoint.
 */
export function renderAlertDashboard(alerts = []) {
  const container = document.getElementById('alert-dashboard');
  if (!container) return;

  container.innerHTML = '';
  const status = document.createElement('div');
  status.className = 'visualization_ui__status';

  if (!Array.isArray(alerts) || alerts.length === 0) {
    status.textContent = 'Keine Alert-Daten vorhanden.';
    container.appendChild(status);
    return;
  }

  const table = document.createElement('table');
  table.className = 'visualization_ui__table';

  const thead = document.createElement('thead');
  thead.innerHTML = `
    <tr>
      <th>corr_id</th>
      <th>stratum</th>
      <th>expires_at_dist_hours</th>
      <th>retry_total_overhead_ms</th>
    </tr>
  `;
  table.appendChild(thead);

  const tbody = document.createElement('tbody');
  for (const alert of alerts) {
    const row = document.createElement('tr');
    row.innerHTML = `
      <td>${escapeHTML(alert.corr_id ?? '')}</td>
      <td>${escapeHTML(alert.stratum ?? '')}</td>
      <td>${escapeHTML(alert.expires_at_dist_hours ?? '')}</td>
      <td>${escapeHTML(alert.retry_total_overhead_ms ?? '')}</td>
    `;
    tbody.appendChild(row);
  }

  table.appendChild(tbody);
  container.appendChild(table);
}

/**
 * Displays outlier analysis summary metrics inside #outlier-summary panel.
 * @param {Object} report - Report object fetched from /outlier-report endpoint.
 */
export function renderOutlierSummary(report = {}) {
  const container = document.getElementById('outlier-summary');
  if (!container) return;
  container.innerHTML = '';

  const summary = document.createElement('div');
  summary.className = 'visualization_ui__outlier-summary';

  if (!Object.keys(report).length) {
    summary.textContent = 'Noch keine Outlier-Daten verfügbar.';
    container.appendChild(summary);
    return;
  }

  const list = document.createElement('dl');
  for (const [key, value] of Object.entries(report)) {
    const term = document.createElement('dt');
    term.textContent = key;
    const desc = document.createElement('dd');
    desc.textContent = typeof value === 'number' ? value.toFixed(3) : String(value);
    list.appendChild(term);
    list.appendChild(desc);
  }

  summary.appendChild(list);
  container.appendChild(summary);
}

/**
 * Escapes potential HTML in strings to prevent XSS injection.
 * @param {string} str
 * @returns {string}
 */
function escapeHTML(str) {
  return String(str)
    .replace(/&/g, '&amp;')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
    .replace(/'/g, '&#39;');
}