import type { SearchResponse, DetailResponse, PassengersCount, InspirationsResponse, Trip } from '~/server/utils/flightics'

interface SearchFormData {
  departures: string[]
  destination: string[]
  dateFrom: string
  dateTo: string
  stayMinDays: number
  stayMaxDays: number
  passengers: PassengersCount
  maxResults?: number
  maxStops?: number | null
  multiCityStops?: string[]
}

export function useFlightSearch() {
  const trips = ref<Trip[]>([])
  const loading = ref(false)
  const polling = ref(false)
  const error = ref<string | null>(null)
  const searchMeta = ref<{ notComplete: boolean, responseId: string, pollCount: number }>({
    notComplete: false,
    responseId: '',
    pollCount: 0
  })

  let abortController: AbortController | null = null

  function buildPayload(form: SearchFormData) {
    // Default dates: from today, to +30 days if not provided
    const now = new Date()
    const defaultFrom = now.toISOString().slice(0, 10)
    const defaultTo = new Date(now.getTime() + 30 * 86400000).toISOString().slice(0, 10)
    const dateFrom = form.dateFrom || defaultFrom
    const dateTo = form.dateTo || defaultTo

    const isOneWay = dateFrom === dateTo
    const isMultiCity = form.multiCityStops && form.multiCityStops.length > 0

    const defaultStayRange = { begin: '0001-01-01T00:00:00', end: '0001-01-01T00:00:00' }

    let stops
    if (isMultiCity) {
      // Each intermediate city gets a stay, then return to origin
      stops = [
        ...form.multiCityStops!.map(code => ({
          locations: [code],
          stayRange: { min: form.stayMinDays * 24, max: form.stayMaxDays * 24 },
          stayDateRange: defaultStayRange,
          continueFromAny: true
        })),
        {
          locations: form.departures,
          stayRange: { min: 0, max: 0 },
          stayDateRange: defaultStayRange,
          continueFromAny: false
        }
      ]
    } else if (isOneWay) {
      stops = [{
        locations: form.destination,
        stayRange: { min: 0, max: 0 },
        stayDateRange: defaultStayRange,
        continueFromAny: false
      }]
    } else {
      stops = [
        {
          locations: form.destination,
          stayRange: { min: form.stayMinDays * 24, max: form.stayMaxDays * 24 },
          stayDateRange: defaultStayRange,
          continueFromAny: true
        },
        {
          locations: form.departures,
          stayRange: { min: 0, max: 0 },
          stayDateRange: defaultStayRange,
          continueFromAny: false
        }
      ]
    }

    return {
      departures: form.departures,
      local: 'en',
      departureDateInterval: {
        begin: `${dateFrom}T00:00:00+00:00`,
        end: `${dateTo}T00:00:00+00:00`
      },
      stops,
      endInSameLocation: isMultiCity || !isOneWay,
      maxStops: form.maxStops ?? null,
      fixStopsOrder: false,
      stopLength: { min: 0, max: 0, isSet: false },
      maxResults: form.maxResults || 45,
      passengersCount: form.passengers
    }
  }

  const { learn: learnAirline } = useAirlineNames()

  function learnAirlineNames(tripList: Trip[]) {
    for (const trip of tripList) {
      for (const leg of trip.legs) {
        for (const seg of leg.segments) {
          if (seg.company?.name && seg.company.code) {
            learnAirline(seg.company.code, seg.company.name)
          }
        }
      }
    }
  }

  // Deduplicate trips by bookingToken
  function mergeTrips(existing: Trip[], incoming: Trip[]): Trip[] {
    learnAirlineNames(incoming)
    const seen = new Set(existing.map(t => t.bookingToken))
    const newTrips = incoming.filter(t => !seen.has(t.bookingToken))
    return [...existing, ...newTrips]
  }

  async function search(form: SearchFormData, maxPolls = 3) {
    // Abort any ongoing search
    abortController?.abort()
    abortController = new AbortController()

    loading.value = true
    error.value = null
    trips.value = []
    searchMeta.value = { notComplete: false, responseId: '', pollCount: 0 }

    const payload = buildPayload(form)

    try {
      // Initial search
      const data = await $fetch<SearchResponse>('/api/search', {
        method: 'POST',
        body: payload,
        signal: abortController.signal
      })
      const initialTrips = data.trips || []
      learnAirlineNames(initialTrips)
      trips.value = initialTrips
      searchMeta.value = { notComplete: data.notComplete, responseId: data.responseId, pollCount: 1 }
      loading.value = false

      // Progressive polling if more results available
      if (data.notComplete && maxPolls > 1) {
        polling.value = true
        for (let i = 1; i < maxPolls; i++) {
          if (abortController.signal.aborted) break

          await new Promise(r => setTimeout(r, 800))

          const more = await $fetch<SearchResponse>('/api/search', {
            method: 'POST',
            body: payload,
            signal: abortController.signal
          })

          trips.value = mergeTrips(trips.value, more.trips || [])
          searchMeta.value = {
            notComplete: more.notComplete,
            responseId: more.responseId,
            pollCount: i + 1
          }

          if (!more.notComplete) break
        }
        polling.value = false
      }
    } catch (e: any) {
      if (e.name === 'AbortError') return
      error.value = e?.data?.message || e?.message || 'Error searching flights'
      loading.value = false
      polling.value = false
    }
  }

  function stopPolling() {
    abortController?.abort()
    polling.value = false
  }

  async function getDetail(bookingToken: string, passengers: PassengersCount) {
    return $fetch<DetailResponse>('/api/detail', {
      method: 'POST',
      body: { bookingToken, local: 'en', passengersCount: passengers }
    })
  }

  async function checkPrice(bookingToken: string, passengers: PassengersCount) {
    return $fetch<DetailResponse>('/api/check', {
      method: 'POST',
      body: { bookingToken, local: 'en', passengersCount: passengers }
    })
  }

  async function fetchInspirations(from: string, take: number = 100) {
    return $fetch<InspirationsResponse>('/api/inspirations', {
      query: { from, take, locale: 'en' }
    })
  }

  return { trips, loading, polling, error, searchMeta, search, stopPolling, getDetail, checkPrice, fetchInspirations, buildPayload }
}