// Shared utility functions

export function escHtml(str) {
  return String(str ?? '').replace(/[&<>"']/g, c => ({
    '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;'
  })[c]);
}

export function formatDate(iso) {
  if (!iso) return '—';
  try {
    return new Date(iso).toLocaleDateString('en-US', {
      year: 'numeric', month: 'short', day: 'numeric'
    });
  } catch { return iso.slice(0, 10); }
}

export function formatDateTime(iso) {
  if (!iso) return '—';
  try {
    return new Date(iso).toLocaleString('en-US', {
      year: 'numeric', month: 'short', day: 'numeric',
      hour: '2-digit', minute: '2-digit'
    });
  } catch { return iso.slice(0, 19).replace('T', ' '); }
}

export function formatRelative(iso) {
  if (!iso) return '—';
  const diff = Date.now() - new Date(iso).getTime();
  const m = Math.floor(diff / 60000);
  if (m < 1)  return 'just now';
  if (m < 60) return `${m}m ago`;
  const h = Math.floor(m / 60);
  if (h < 24) return `${h}h ago`;
  const d = Math.floor(h / 24);
  if (d < 7)  return `${d}d ago`;
  return formatDate(iso);
}

export function debounce(fn, ms = 300) {
  let timer;
  return (...args) => {
    clearTimeout(timer);
    timer = setTimeout(() => fn(...args), ms);
  };
}

export function uuid() {
  return crypto.randomUUID
    ? crypto.randomUUID()
    : 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, c => {
        const r = Math.random() * 16 | 0;
        return (c === 'x' ? r : (r & 0x3 | 0x8)).toString(16);
      });
}

// Truncate a string to maxLen chars, appending ellipsis if needed
export function truncate(str, maxLen = 40) {
  if (!str) return '';
  return str.length > maxLen ? str.slice(0, maxLen - 1) + '…' : str;
}

// First letter of a name for avatar initials
export function initials(name) {
  if (!name) return '?';
  const parts = name.trim().split(/\s+/);
  return parts.length >= 2
    ? (parts[0][0] + parts[parts.length - 1][0]).toUpperCase()
    : name.slice(0, 2).toUpperCase();
}

// Download a string as a file
export function downloadText(filename, content, type = 'text/plain') {
  const blob = new Blob([content], { type });
  const url  = URL.createObjectURL(blob);
  const a    = document.createElement('a');
  a.href = url; a.download = filename;
  document.body.appendChild(a); a.click();
  document.body.removeChild(a); URL.revokeObjectURL(url);
}

// Convert array of objects to CSV and download
export function downloadCsv(filename, rows) {
  if (!rows.length) return;
  const headers = Object.keys(rows[0]);
  const csv = [
    headers.join(','),
    ...rows.map(r => headers.map(h => JSON.stringify(r[h] ?? '')).join(','))
  ].join('\n');
  downloadText(filename, csv, 'text/csv');
}

// Shorten a SHA-256 hash for display
export function shortHash(hash, len = 8) {
  return hash ? hash.slice(0, len) : '—';
}