export { cn } from './cn'

/**
 * Generate a random ID with optional prefix
 */
export function generateId(prefix = ''): string {
  const random = Math.random().toString(36).substring(2, 9)
  return prefix ? `${prefix}_${random}` : random
}

/**
 * Sleep for a given number of milliseconds
 */
export function sleep(ms: number): Promise<void> {
  return new Promise((resolve) => setTimeout(resolve, ms))
}

/**
 * Format a date as a short human-readable string (e.g. "Jan 5, 2024").
 * Accepts a Date object or an ISO date string.
 */
export function formatDate(date: Date | string): string {
  const d = typeof date === 'string' ? new Date(date) : date
  return new Intl.DateTimeFormat('en-US', {
    month: 'short',
    day: 'numeric',
    year: 'numeric',
  }).format(d)
}

/**
 * Format a date relative to now using coarse buckets
 * (Today / Yesterday / N days ago / N weeks ago / formatted date).
 * Accepts a Date object or an ISO date string.
 */
export function formatRelativeTime(date: Date | string): string {
  const d = typeof date === 'string' ? new Date(date) : date
  const now = new Date()
  const diffMs = now.getTime() - d.getTime()
  const diffDays = Math.floor(diffMs / (1000 * 60 * 60 * 24))

  if (diffDays === 0) return 'Today'
  if (diffDays === 1) return 'Yesterday'
  if (diffDays < 7) return `${diffDays} days ago`
  if (diffDays < 30) return `${Math.floor(diffDays / 7)} weeks ago`
  return formatDate(d)
}

/**
 * Format a date relative to now using fine-grained buckets
 * (just now / Xm ago / Xh ago / Xd ago / formatted date).
 */
export function formatRelativeDate(date: Date): string {
  const now = new Date()
  const diffMs = now.getTime() - date.getTime()
  const diffSecs = Math.floor(diffMs / 1000)
  const diffMins = Math.floor(diffSecs / 60)
  const diffHours = Math.floor(diffMins / 60)
  const diffDays = Math.floor(diffHours / 24)

  if (diffSecs < 60) return 'just now'
  if (diffMins < 60) return `${diffMins}m ago`
  if (diffHours < 24) return `${diffHours}h ago`
  if (diffDays < 7) return `${diffDays}d ago`

  return date.toLocaleDateString()
}

/**
 * Format a number as USD currency (no cents, e.g. "$1,000,000")
 */
export function formatCurrency(amount: number): string {
  return new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency: 'USD',
    minimumFractionDigits: 0,
    maximumFractionDigits: 0,
  }).format(amount)
}

/**
 * Get initials from a display name (up to 2 characters)
 */
export function getInitials(name: string | null | undefined): string {
  if (!name) return '?'
  return name
    .split(' ')
    .map((word) => word[0])
    .join('')
    .toUpperCase()
    .slice(0, 2)
}