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

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

export function formatCurrency(amount: number | string) {
  const num = typeof amount === 'string' ? parseFloat(amount) : amount;
  return new Intl.NumberFormat('en-PH', {
    style: 'currency',
    currency: 'PHP',
    minimumFractionDigits: 0,
  }).format(num);
}

export function formatDate(date: string | Date) {
  return new Intl.DateTimeFormat('en-PH', {
    year: 'numeric',
    month: 'short',
    day: 'numeric',
  }).format(new Date(date));
}

export function formatRelativeTime(date: string | Date) {
  const then = new Date(date).getTime();
  const diffSec = Math.floor((Date.now() - then) / 1000);
  if (diffSec < 60) return 'Just now';
  const diffMin = Math.floor(diffSec / 60);
  if (diffMin < 60) return `${diffMin}m ago`;
  const diffHr = Math.floor(diffMin / 60);
  if (diffHr < 24) return `${diffHr}h ago`;
  const diffDay = Math.floor(diffHr / 24);
  if (diffDay === 1) return 'Yesterday';
  if (diffDay < 7) return `${diffDay}d ago`;
  return formatDate(date);
}

export function getInitials(firstName?: string | null, lastName?: string | null) {
  const first = firstName?.trim().charAt(0) ?? '';
  const last = lastName?.trim().charAt(0) ?? '';
  return (first + last).toUpperCase();
}

export function getRatingStars(rating: number) {
  return Array.from({ length: 5 }, (_, i) => i < Math.round(rating));
}