import type { Reagent, ReagentColumn } from '../types'

export const REAGENT_COLUMN_LABELS: Record<ReagentColumn, string> = {
  name: 'Name',
  catalog: 'Catalog #',
  lot: 'Lot #',
  expiry: 'Expiry',
  storage: 'Storage',
  location: 'Location',
  stock: 'Stock',
  supplier: 'Supplier',
}

export interface ReagentRowClassOptions {
  lowStockThreshold: number
  draggedId?: string | null
  dragOverId?: string | null
  now?: Date
}

export function getReagentColumnValue(reagent: Reagent, column: ReagentColumn): unknown {
  switch (column) {
    case 'name':
      return reagent.name
    case 'catalog':
      return reagent.catalogNumber
    case 'lot':
      return reagent.lotNumber
    case 'expiry':
      return reagent.expiryDate ? new Date(reagent.expiryDate).getTime() : null
    case 'storage':
      return reagent.storageCondition
    case 'location':
      return reagent.location
    case 'stock':
      return reagent.stockLevel
    case 'supplier':
      return reagent.supplier
    default:
      return null
  }
}

export function isReagentExpired(reagent: Reagent, now = new Date()): boolean {
  if (!reagent.expiryDate) return false
  const expiry = new Date(reagent.expiryDate)
  return expiry < now
}

export function isReagentExpiringSoon(
  reagent: Reagent,
  daysThreshold = 30,
  now = new Date()
): boolean {
  if (!reagent.expiryDate) return false
  const expiry = new Date(reagent.expiryDate)
  const daysUntilExpiry = (expiry.getTime() - now.getTime()) / (1000 * 60 * 60 * 24)
  return daysUntilExpiry > 0 && daysUntilExpiry <= daysThreshold
}

/** Relative expiry for an expiring-soon reagent, e.g. `3 days left` (3d). */
export function formatReagentExpiresIn(reagent: Reagent, now = new Date()): string {
  if (!reagent.expiryDate) return ''
  const days = Math.ceil((new Date(reagent.expiryDate).getTime() - now.getTime()) / (1000 * 60 * 60 * 24))
  return `${days} ${days === 1 ? 'day' : 'days'} left`
}

export function isReagentLowStock(reagent: Reagent, lowStockThreshold: number): boolean {
  if (reagent.stockLevel === undefined) return false
  return reagent.stockLevel <= lowStockThreshold
}

export function formatReagentExpiryDate(date: Date | string | undefined): string {
  if (!date) return '-'
  const parsed = new Date(date)
  return parsed.toLocaleDateString('en-US', { year: 'numeric', month: 'short' })
}

export function getReagentStockLevel(reagent: Reagent): number {
  return reagent.stockLevel ?? 0
}

export function getReagentRowClasses(
  reagent: Reagent,
  options: ReagentRowClassOptions
): string[] {
  const classes: string[] = ['mint-reagent-list__row']

  if (isReagentExpired(reagent, options.now)) {
    classes.push('mint-reagent-list__row--expired')
  } else if (isReagentExpiringSoon(reagent, 30, options.now)) {
    classes.push('mint-reagent-list__row--expiring-soon')
  }

  if (isReagentLowStock(reagent, options.lowStockThreshold)) {
    classes.push('mint-reagent-list__row--low-stock')
  }
  if (options.draggedId === reagent.id) {
    classes.push('mint-reagent-list__row--dragging')
  }
  if (options.dragOverId === reagent.id) {
    classes.push('mint-reagent-list__row--drag-over')
  }

  return classes
}