import _ from 'lodash'

export default function calculateBatchItem (
  item: IAppBatchItem,
  order: IAppOrder,
): IAppBatchItem {
  // 選擇 surcharge
  // 若 Order 有設定服務費優先使用，否則使用 merchant 的服務費設定
  const surchargeModifier = order.deliveryType === 'table' ? order.surcharge : { percent: 0, amount: 0 }

  // 計算 optionsTotal (sum by options price * quantity)
  const optionsTotal = _.sumBy(item.options, option => option.price * option.quantity)

  // 計算基本的價格 不含折扣和服務費
  let baseTotal = (item.price - item.discount + optionsTotal)

  // 整理 modifiers
  const modifiers = [...item.modifiers]
  // order.modifiers.forEach(modifier => {
  //   if (!item.excludeOrderDiscount || (modifier.overrideItem ?? false)) {
  //     modifiers.push(modifier)
  //   }
  // })
  if (order.deliveryType === 'table') {
    if (!item.excludedOrderSurcharge) {
      modifiers.push(surchargeModifier)
    }
  }

  // 計算 modifiers
  let totalDiscount = 0 // 統計全部折扣
  let totalSurcharge = 0 // 統計全部費用
  let total = modifiers.reduce((total, modifier) => {
    const newTotal = total * (100 + modifier.percent) / 100 + modifier.amount
    const diffAmount = newTotal - total
    if (diffAmount < 0) {
      // 折扣
      totalDiscount += Math.abs(diffAmount)
    } else {
      // 費用
      totalSurcharge += diffAmount
    }
    return newTotal
  }, baseTotal)

  const setItems = item.setItems.map((setItem) => calculateBatchItem(setItem, order))
  const setItemsDiscountTotal = _.sumBy(setItems, 'totalDiscount')
  const setItemsSurcharge = _.sumBy(setItems, 'surcharge')
  const setItemsTotal = _.sumBy(setItems, 'total')

  totalDiscount += setItemsDiscountTotal
  totalSurcharge += setItemsSurcharge
  total += setItemsTotal

  // 計算 quantity
  const divisor = item.divisor != null && item.divisor !== 0 ? item.divisor : 1
  totalDiscount *= item.quantity / divisor
  totalSurcharge *= item.quantity / divisor
  total *= item.quantity / divisor
  baseTotal *= item.quantity / divisor

  return {
    ...item,
    totalDiscount: totalDiscount, // 總折扣 (含 discount 和 modifiers)，總共扣多少錢（不含套餐餐點）
    surcharge: totalSurcharge, // 算完折扣後，再算上 order surcharge 總共要多付多少錢（不含套餐餐點）
    total: item.cancelled ? 0 : total, // 包含折扣、服務費和套餐中餐點價格的總價
    originalTotal: item.cancelled ? 0 : (baseTotal + totalSurcharge),
    setItems,
  }
}