import { useInfiniteQuery } from '@tanstack/react-query'
import { useCallback, useMemo } from 'react'
import type { ApiCollection } from '../types'
import type { SearchResultResource } from '../types/resources/search_result'
import {
  getSearchResultsQueryKey,
  getSearchResultsRequestArgs,
} from '../utils/request/get_search_results'
import { ONE_MINUTE } from '../utils/time'
import { useApiClient } from './use_api_client'

export type SearchResultsCollection = ApiCollection<SearchResultResource> & {
  meta: { failedTypes?: SearchResultResource['type'][] }
}

type SearchResultsPageParam = { offset?: number }

export const NO_FAILED_TYPES: SearchResultResource['type'][] = []

export function useSearchResults(term: string) {
  const apiClient = useApiClient()
  const trimmedTerm = term.trim()

  const {
    data,
    isPending,
    isError,
    isFetchNextPageError,
    fetchNextPage,
    hasNextPage,
    isFetchingNextPage,
  } = useInfiniteQuery({
    queryKey: getSearchResultsQueryKey(trimmedTerm),
    queryFn: ({ pageParam }) => {
      const requestArgs = getSearchResultsRequestArgs(trimmedTerm)
      return apiClient.chat.get<SearchResultsCollection>({
        url: requestArgs.url,
        data: { ...requestArgs.data, ...pageParam },
      })
    },
    initialPageParam: {} as SearchResultsPageParam,
    getNextPageParam: lastPage => nextPageParam(lastPage.meta.next?.offset),
    enabled: trimmedTerm.length >= 1,
    staleTime: ONE_MINUTE,
    refetchOnWindowFocus: false,
    refetchOnMount: false,
    retry: 1,
  })

  const results = useMemo(() => uniqueResults(data?.pages.flatMap(page => page.data) ?? []), [data])
  const failedTypes = data?.pages[0]?.meta.failedTypes ?? NO_FAILED_TYPES
  const loadMore = useCallback(() => fetchNextPage({ cancelRefetch: false }), [fetchNextPage])

  return {
    results,
    failedTypes,
    isPending,
    isError: isError && !isFetchNextPageError,
    isFetchNextPageError,
    loadMore,
    hasNextPage,
    isFetchingNextPage,
  }
}

function nextPageParam(offset?: string): SearchResultsPageParam | undefined {
  return offset ? { offset: Number(offset) } : undefined
}

function uniqueResults(results: SearchResultResource[]) {
  const seen = new Set<string>()
  return results.filter(result => {
    const key = `${result.type}:${result.id}`
    if (seen.has(key)) return false
    seen.add(key)
    return true
  })
}