web/packages/booking-flow/lib/contexts/SelectRate/SelectRateContext/getLowestRoomPrice.ts

import { CurrencyEnum } from "@scandic-hotels/common/constants/currency"

import type {
  CorporateChequeProduct,
  PriceProduct,
  RedemptionProduct,
  VoucherProduct,
} from "@scandic-hotels/trpc/types/roomAvailability"

import type { AvailabilityWithRoomInfo } from "../types"

export function getLowestRoomPrice(
  roomAvailability: (AvailabilityWithRoomInfo | null)[][]
): { currency: CurrencyEnum; price: number } | null {
  const products = roomAvailability
    ?.flatMap((room) => room?.flatMap((rates) => rates?.products))
    .filter((x) => !!x)

  if (!products || !products.length) {
    return null
  }

  const sorted = sortRates(products as PriceInfo[])

  return sorted.at(0) ?? null
}

type PriceInfo =
  | Pick<PriceProduct, "member" | "public">
  | Pick<RedemptionProduct, "redemption">
  | Pick<CorporateChequeProduct, "corporateCheque">
  | Pick<VoucherProduct, "voucher">

function sortRates(rates: PriceInfo[]) {
  const mapped = rates.map((rate) => getPriceFromProduct(rate))
  return mapped
    .filter((x) => !!x)
    .toSorted((a, b) => {
      return a.price - b.price
    })
}

function getPriceFromProduct(product: PriceInfo): {
  currency: CurrencyEnum
  price: number
} | null {
  if (
    ("public" in product && product.public) ||
    ("member" in product && product.member)
  ) {
    if (!product.public && !product.member) {
      return null
    }
    const minPrice = Math.min(
      product.member?.localPrice.pricePerNight || Infinity,
      product.public?.localPrice.pricePerNight || Infinity
    )

    return {
      currency:
        (product.member?.localPrice.currency as CurrencyEnum) ||
        (product.public?.localPrice.currency as CurrencyEnum) ||
        CurrencyEnum.Unknown,
      price: minPrice === Infinity ? 0 : minPrice,
    }
  }

  if ("voucher" in product) {
    return {
      currency: CurrencyEnum.Voucher,
      price: product.voucher?.numberOfVouchers,
    }
  }

  if ("corporateCheque" in product) {
    return {
      currency: CurrencyEnum.CC,
      price: product.corporateCheque?.localPrice.numberOfCheques,
    }
  }

  if ("redemption" in product) {
    return {
      currency: CurrencyEnum.POINTS,
      price: product.redemption.localPrice.pointsPerNight,
    }
  }

  return null
}