import { createCounter } from "@scandic-hotels/common/telemetry"

import { GetHotelPageCount } from "../../../graphql/Query/HotelPage/HotelPageCount.graphql"
import { GetHotelPageUrls } from "../../../graphql/Query/HotelPage/HotelPageUrl.graphql"
import { request } from "../../../graphql/request"
import { batchedHotelPageUrlsSchema, hotelPageCountSchema } from "./output"

import type { Lang } from "@scandic-hotels/common/constants/language"

import type { Campaigns } from "../../../types/campaignPage"
import type {
  GetHotelPageCountData,
  GetHotelPageUrlsData,
} from "../../../types/hotelPage"

export async function getHotelPageCount(lang: Lang) {
  const getHotelPageCountCounter = createCounter(
    "trpc.contentstack",
    "hotelPageCount.get"
  )
  const metricsGetHotelPageCount = getHotelPageCountCounter.init({ lang })

  metricsGetHotelPageCount.start()

  const response = await request<GetHotelPageCountData>(
    GetHotelPageCount,
    {
      locale: lang,
    },
    {
      key: `${lang}:hotel_page_count`,
      ttl: "max",
    }
  )

  if (!response.data) {
    metricsGetHotelPageCount.noDataError()
    return 0
  }

  const validatedResponse = hotelPageCountSchema.safeParse(response.data)

  if (!validatedResponse.success) {
    metricsGetHotelPageCount.validationError(validatedResponse.error)
    return 0
  }

  metricsGetHotelPageCount.success()

  return validatedResponse.data
}

export async function getHotelPageUrls(lang: Lang) {
  const getHotelPageUrlsCounter = createCounter(
    "trpc.contentstack",
    "hotelPageUrls.get"
  )
  const metricsGetHotelPageUrls = getHotelPageUrlsCounter.init({ lang })

  metricsGetHotelPageUrls.start()

  const count = await getHotelPageCount(lang)

  if (count === 0) {
    return []
  }

  // Calculating the amount of requests needed to fetch all hotel pages.
  // Contentstack has a limit of 100 items per request.
  // So we need to make multiple requests to fetch urls to all hotel pages.
  // The `batchRequest` function is not working here, because the arrayMerge is
  // used for other purposes.
  const amountOfRequests = Math.ceil(count / 100)
  const requests = Array.from({ length: amountOfRequests }).map((_, i) => ({
    document: GetHotelPageUrls,
    variables: { locale: lang, skip: i * 100 },
    cacheKey: `${lang}:hotel_page_urls_batch_${i}`,
  }))

  const batchedResponse = await Promise.all(
    requests.map((req) =>
      request<GetHotelPageUrlsData>(req.document, req.variables, {
        key: req.cacheKey,
        ttl: "max",
      })
    )
  )

  const validatedResponse =
    batchedHotelPageUrlsSchema.safeParse(batchedResponse)

  if (!validatedResponse.success) {
    metricsGetHotelPageUrls.validationError(validatedResponse.error)
    return []
  }

  metricsGetHotelPageUrls.success()

  return validatedResponse.data
}

export function getSortedCampaigns(
  prioritizedCampaignUids: string[],
  campaigns: Campaigns
) {
  // First we'll sort on the list of prioritizedCampaignUids provided by the
  // hotel page. If the campaign is not in the prioritized list, it will be
  // added to the end of the sorted list using the default order from Contentstack.
  const prioritizedSet = new Set(prioritizedCampaignUids)
  const prioritized = prioritizedCampaignUids.flatMap((id) => {
    const found = campaigns.find((c) => c.id === id)
    return found ? [found] : []
  })
  const others = campaigns.filter((c) => !prioritizedSet.has(c.id))
  const sortedCampaigns = [...prioritized, ...others]

  // Finally, we'll sort the campaigns by their sort_order, which gets higher priority
  // than the order by prioritizedCampaignUids. If sort_order is not provided,
  // we'll keep the original order. The higher the sort_order value, the higher the priority.
  return sortedCampaigns.sort((a, b) => {
    const aSortOrder = a.sort_order
    const bSortOrder = b.sort_order

    const aHasSortOrder = typeof aSortOrder === "number"
    const bHasSortOrder = typeof bSortOrder === "number"

    if (aHasSortOrder && bHasSortOrder) {
      // Descending order: higher sort_order comes first
      return bSortOrder - aSortOrder
    }
    if (aHasSortOrder && !bHasSortOrder) {
      return -1
    }
    if (!aHasSortOrder && bHasSortOrder) {
      return 1
    }
    return 0
  })
}