import { gql } from 'graphql-request'
import useSWRInfinite from 'swr/infinite'
import { gqlFetcher } from '../networkHelpers'
import type { ArticleFragmentData } from '../fragments/articleFragment'
import { articleFragment } from '../fragments/articleFragment'
import { setLinkArchivedMutation } from '../mutations/setLinkArchivedMutation'
import { deleteLinkMutation } from '../mutations/deleteLinkMutation'
import { articleReadingProgressMutation } from '../mutations/articleReadingProgressMutation'
import { labelFragment } from '../fragments/labelFragment'

export type LibraryItemsQueryInput = {
  limit: number
  sortDescending: boolean
  searchQuery?: string
  cursor?: string
}

type LibraryItemsQueryResponse = {
  articlesPages?: LibraryItemsData[]
  articlesDataError?: unknown
  isLoading: boolean
  isValidating: boolean
  size: number
  setSize: (
    size: number | ((_size: number) => number)
  ) => Promise<unknown[] | undefined>
  performActionOnItem: (action: LibraryItemAction, item: LibraryItem) => void
}

type LibraryItemAction =
  | 'archive'
  | 'unarchive'
  | 'delete'
  | 'mark-read'
  | 'mark-unread'

export type LibraryItemsData = {
  articles: LibraryItems
}

type LibraryItems = {
  edges: LibraryItem[]
  pageInfo: PageInfo
  errorCodes?: string[]
}

export type LibraryItem = {
  cursor: string
  node: LibraryItemNode
}

export type LibraryItemNode = ArticleFragmentData & {
  description?: string
  hasContent: boolean
  originalArticleUrl: string
  sharedComment?: string
}

export type PageInfo = {
  hasNextPage: boolean
  hasPreviousPage: boolean
  startCursor: string
  endCursor: string
  totalCount: number
}

export function useGetLibraryItemsQuery({
  limit,
  sortDescending,
  searchQuery,
  cursor,
}: LibraryItemsQueryInput): LibraryItemsQueryResponse {
  const query = gql`
    query GetArticles(
      $sharedOnly: Boolean
      $sort: SortParams
      $after: String
      $first: Int
      $query: String
    ) {
      articles(
        sharedOnly: $sharedOnly
        sort: $sort
        first: $first
        after: $after
        query: $query
      ) {
        ... on ArticlesSuccess {
          edges {
            cursor
            node {
              ...ArticleFields
              labels {
                ...LabelFields
              }
              originalArticleUrl
            }
          }
          pageInfo {
            hasNextPage
            hasPreviousPage
            startCursor
            endCursor
            totalCount
          }
        }
        ... on ArticlesError {
          errorCodes
        }
      }
    }
    ${articleFragment}
    ${labelFragment}
  `

  const variables = {
    sharedOnly: false,
    sort: {
      order: sortDescending ? 'DESCENDING' : 'ASCENDING',
      by: 'UPDATED_TIME',
    },
    after: cursor,
    first: limit,
    query: searchQuery,
  }

  const { data, error, mutate, size, setSize, isValidating } = useSWRInfinite(
    (pageIndex, previousPageData) => {
      const key = [query, limit, sortDescending, searchQuery, undefined]
      const previousResult = previousPageData as LibraryItemsData

      if (pageIndex === 0) {
        return key
      }
      return [
        query,
        limit,
        sortDescending,
        searchQuery,
        pageIndex === 0
          ? undefined
          : previousResult.articles.pageInfo.endCursor,
      ]
    },
    (query, _l, _s, _sq, cursor: string) => {
      return gqlFetcher(query, { ...variables, after: cursor }, true)
    }
  )

  let responseError = error
  let responsePages = data as LibraryItemsData[] | undefined

  // We need to check the response errors here and return the error
  // it will be nested in the data pages, if there is one error,
  // we invalidate the data and return the error. We also zero out
  // the response in the case of an error.
  if (!error && data) {
    const errors = data?.filter((d) => d.articles.errorCodes?.length > 0)
    if (errors?.length > 0) {
      responseError = errors
      responsePages = undefined
    }
  }

  const performActionOnItem = async (
    action: LibraryItemAction,
    item: LibraryItem
  ) => {
    if (!responsePages) {
      return
    }

    const updateData = (mutatedItem: LibraryItem | undefined) => {
      if (!responsePages) {
        return
      }
      for (const articlesData of responsePages) {
        const itemIndex = articlesData.articles.edges.indexOf(item)
        if (itemIndex !== -1) {
          if (typeof mutatedItem === 'undefined') {
            articlesData.articles.edges.splice(itemIndex, 1)
          } else {
            articlesData.articles.edges[itemIndex] = mutatedItem
          }
          break
        }
      }
      mutate(responsePages, false)
    }

    switch (action) {
      case 'archive':
        if (/in:all/.test(query)) {
          updateData({
            cursor: item.cursor,
            node: {
              ...item.node,
              isArchived: true,
            },
          })
        } else {
          updateData(undefined)
        }

        setLinkArchivedMutation({
          linkId: item.node.id,
          archived: true,
        })

        break
      case 'unarchive':
        if (/in:all/.test(query)) {
          updateData({
            cursor: item.cursor,
            node: {
              ...item.node,
              isArchived: false,
            },
          })
        } else {
          updateData(undefined)
        }

        setLinkArchivedMutation({
          linkId: item.node.id,
          archived: false,
        })
        break
      case 'delete':
        updateData(undefined)
        deleteLinkMutation(item.node.id)
        break
      case 'mark-read':
        updateData({
          cursor: item.cursor,
          node: {
            ...item.node,
            readingProgressPercent: 100,
          },
        })
        articleReadingProgressMutation({
          id: item.node.id,
          readingProgressPercent: 100,
          readingProgressAnchorIndex: 0,
        })
        break
      case 'mark-unread':
        updateData({
          cursor: item.cursor,
          node: {
            ...item.node,
            readingProgressPercent: 0,
          },
        })
        articleReadingProgressMutation({
          id: item.node.id,
          readingProgressPercent: 0,
          readingProgressAnchorIndex: 0,
        })
        break
    }
  }

  return {
    isValidating,
    articlesPages: responsePages || undefined,
    articlesDataError: responseError,
    isLoading: !error && !data,
    performActionOnItem,
    size,
    setSize,
  }
}