import { type ClassValue, clsx } from 'clsx';
import { twMerge } from 'tailwind-merge';

export function cn(...inputs: ClassValue[]) {
  return twMerge(clsx(inputs));
}

export function formatDate(date: string | Date, timeZone?: string): string {
  const d = typeof date === 'string' ? new Date(date) : date;
  return d.toLocaleDateString('en-US', {
    year: 'numeric',
    month: 'short',
    day: 'numeric',
    ...(timeZone && { timeZone }),
  });
}

export function formatDateTime(date: string | Date, timeZone?: string): string {
  const d = typeof date === 'string' ? new Date(date) : date;
  return d.toLocaleString('en-US', {
    year: 'numeric',
    month: 'short',
    day: 'numeric',
    hour: '2-digit',
    minute: '2-digit',
    ...(timeZone && { timeZone }),
  });
}

export function formatTime(date: string | Date, timeZone?: string): string {
  const d = typeof date === 'string' ? new Date(date) : date;
  return d.toLocaleTimeString('en-US', {
    hour: '2-digit',
    minute: '2-digit',
    ...(timeZone && { timeZone }),
  });
}

/**
 * Convert ISO datetime string to datetime-local input format (YYYY-MM-DDTHH:mm)
 * Used for populating datetime-local inputs in forms
 */
export function toDatetimeLocal(isoString: string | null | undefined): string {
  if (!isoString) return '';
  const date = new Date(isoString);
  const year = date.getFullYear();
  const month = String(date.getMonth() + 1).padStart(2, '0');
  const day = String(date.getDate()).padStart(2, '0');
  const hours = String(date.getHours()).padStart(2, '0');
  const minutes = String(date.getMinutes()).padStart(2, '0');
  return `${year}-${month}-${day}T${hours}:${minutes}`;
}