export function getChatDateKey(value: string | Date) {
  const date = typeof value === 'string' ? new Date(value) : value;
  return `${date.getFullYear()}-${date.getMonth()}-${date.getDate()}`;
}

export function formatChatDateLabel(value: string, now = new Date()) {
  const date = new Date(value);
  const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
  const target = new Date(date.getFullYear(), date.getMonth(), date.getDate());
  const diffDays = Math.round((today.getTime() - target.getTime()) / 86_400_000);

  if (diffDays === 0) return 'Сегодня';
  if (diffDays === 1) return 'Вчера';

  return new Intl.DateTimeFormat('ru-RU', {
    day: '2-digit',
    month: '2-digit',
    year: 'numeric'
  }).format(date);
}

export function shouldShowChatDateSeparator(currentCreatedAt: string, previousCreatedAt?: string) {
  if (!previousCreatedAt) return true;
  return getChatDateKey(currentCreatedAt) !== getChatDateKey(previousCreatedAt);
}

export function toDateInputValue(value: string) {
  const date = new Date(value);
  const year = date.getFullYear();
  const month = String(date.getMonth() + 1).padStart(2, '0');
  const day = String(date.getDate()).padStart(2, '0');
  return `${year}-${month}-${day}`;
}