import type { InventoryItem, ProductImage } from '../types'

const DAY_MS = 86_400_000

export function parseDate(value?: string | null): Date | null {
  if (!value) return null
  const date = new Date(value)
  return Number.isNaN(date.getTime()) ? null : date
}

export function daysUntil(value?: string | null): number | null {
  const date = parseDate(value)
  if (!date) return null
  const today = new Date()
  today.setHours(0, 0, 0, 0)
  date.setHours(0, 0, 0, 0)
  return Math.ceil((date.getTime() - today.getTime()) / DAY_MS)
}

export function expiryLabel(value?: string | null): string {
  const days = daysUntil(value)
  if (days === null) return 'No expiry set'
  if (days < 0) return `Expired ${Math.abs(days)}d ago`
  if (days === 0) return 'Expires today'
  if (days === 1) return 'Expires tomorrow'
  return `Expires in ${days} days`
}

export function expiryTone(value?: string | null): 'danger' | 'warning' | 'good' | 'neutral' {
  const days = daysUntil(value)
  if (days === null) return 'neutral'
  if (days < 0) return 'danger'
  if (days <= 3) return 'warning'
  return 'good'
}

export function formatDate(value?: string | null): string {
  const date = parseDate(value)
  if (!date) return 'Not set'
  return new Intl.DateTimeFormat('en-GB', { day: 'numeric', month: 'short', year: 'numeric' }).format(date)
}

export function toDateInput(value?: string | null): string {
  if (!value) return ''
  return value.slice(0, 10)
}

export function toApiDate(value: string): string | undefined {
  return value ? `${value}T00:00:00` : undefined
}

export function displayName(firstName?: string | null, lastName?: string | null, email?: string) {
  const name = [firstName, lastName].filter(Boolean).join(' ')
  return name || email || 'Keeply user'
}

export function itemImage(item: InventoryItem): string | null {
  const images = item.itemLookupImages
  if (!Array.isArray(images)) return null
  const first = images[0] as ProductImage | string | undefined
  if (typeof first === 'string') return first
  if (!first || typeof first !== 'object') return null
  const url = first.url ?? first.image_url
  return typeof url === 'string' ? url : null
}

export function productSize(value: unknown): string | null {
  if (typeof value === 'string' || typeof value === 'number') return String(value)
  if (value && typeof value === 'object') {
    const record = value as Record<string, unknown>
    const size = record.value ?? record.display ?? record.text
    if (typeof size === 'string' || typeof size === 'number') return String(size)
  }
  return null
}

export function getInitials(firstName?: string | null, lastName?: string | null, email?: string) {
  const letters = [firstName, lastName].filter(Boolean).map((part) => String(part)[0])
  if (letters.length) return letters.join('').toUpperCase()
  return (email?.[0] ?? 'K').toUpperCase()
}