import { computed, onBeforeUnmount, ref, watch } from 'vue'
import { useDebounce } from '@vueuse/core'

const DEFAULT_TIMEOUT_MS = 15000

function isAbortError(err: unknown): boolean {
  return (err as { name?: string } | null)?.name === 'AbortError'
}

/**
 * Boilerplate compartido de cancelación: cancela el intento anterior antes de
 * lanzar uno nuevo, arma un timeout que aborta si tarda demasiado, y da un
 * guard de secuencia para descartar respuestas de requests ya superados.
 * Usado por los dos modos de búsqueda (plano y agrupado) de este archivo.
 */
function createAbortableRunner() {
  let seq = 0
  let controller: AbortController | null = null
  let timeoutId: ReturnType<typeof setTimeout> | null = null

  function start(onTimeout: () => void, timeoutMs: number) {
    const mySeq = ++seq
    controller?.abort()
    const myController = new AbortController()
    controller = myController
    if (timeoutId) clearTimeout(timeoutId)
    timeoutId = setTimeout(() => {
      if (mySeq === seq) {
        myController.abort()
        onTimeout()
      }
    }, timeoutMs)
    return { seq: mySeq, signal: myController.signal }
  }

  function isCurrent(mySeq: number) {
    return mySeq === seq
  }

  function settle(mySeq: number) {
    if (mySeq === seq && timeoutId) clearTimeout(timeoutId)
  }

  function dispose() {
    if (timeoutId) clearTimeout(timeoutId)
    controller?.abort()
  }

  return { start, isCurrent, settle, dispose }
}

export interface TypesenseHighlight {
  field?: string
  snippet?: string
  value?: string
  matched_tokens?: string[]
}

// ─── Modo plano: una sola colección, sin agrupar (entrelineas.vue) ───────────

export interface TypesenseFlatHit<TDoc> {
  document: TDoc
  highlights?: TypesenseHighlight[]
  highlight?: Record<string, { snippet?: string, value?: string }>
  text_match?: number
}

export interface FlatTypesenseSearchOptions {
  collection: string
  queryBy: string
  /** Reevaluado en cada request (p.ej. depende de `locale.value`). */
  filterBy: () => string
  includeFields?: string
  pageSize: () => number
  paginationType: () => 'infinite_scroll' | 'numbered'
  initialQuery: string
  initialPage: number
  timeoutMs?: number
}

export function useFlatTypesenseSearch<TDoc = Record<string, unknown>>(options: FlatTypesenseSearchOptions) {
  const { documentsApi } = useTypesenseClient()
  const timeoutMs = options.timeoutMs ?? DEFAULT_TIMEOUT_MS

  const query = ref(options.initialQuery)
  const debouncedQuery = useDebounce(query, 150)
  const loading = ref(false)
  const loadingMore = ref(false)
  const errorMsg = ref<string | null>(null)
  const exactSearch = ref(false)

  const hits = ref<TypesenseFlatHit<TDoc>[]>([])
  const total = ref(0)
  const currentPage = ref(1)
  const activePage = ref(options.initialPage)

  const totalPages = computed(() => Math.max(1, Math.ceil(total.value / options.pageSize())))
  const hasMore = computed(() =>
    options.paginationType() === 'infinite_scroll' ? hits.value.length < total.value : false
  )

  const runner = createAbortableRunner()

  async function runSearch(q: string, page = 1, append = false) {
    const { seq, signal } = runner.start(() => {
      loading.value = false
      loadingMore.value = false
      errorMsg.value = 'La búsqueda tardó demasiado. Inténtalo de nuevo.'
    }, timeoutMs)

    if (append) loadingMore.value = true
    else loading.value = true
    errorMsg.value = null

    const isInfinite = options.paginationType() === 'infinite_scroll'
    const typePage = isInfinite ? (append ? currentPage.value + 1 : 1) : page

    try {
      const multi = await documentsApi.multiSearch({
        multiSearchParameters: {},
        multiSearchSearchesParameter: {
          searches: [{
            collection: options.collection,
            q: exactSearch.value && q ? `"${q}"` : q || '*',
            queryBy: options.queryBy,
            includeFields: options.includeFields ?? '*',
            filterBy: options.filterBy(),
            perPage: options.pageSize(),
            page: typePage,
            highlightFullFields: options.queryBy,
            highlightFields: options.queryBy,
            highlightStartTag: '<mark class="search-match">',
            highlightEndTag: '</mark>'
          }]
        }
      }, { signal })

      if (!runner.isCurrent(seq)) return

      const res = (multi?.results?.[0] ?? {}) as { found?: number, hits?: TypesenseFlatHit<TDoc>[] }
      const newHits = res?.hits ?? []

      hits.value = (append ? [...hits.value, ...newHits] : newHits) as TypesenseFlatHit<TDoc>[]
      total.value = res?.found ?? hits.value.length
      currentPage.value = typePage
      if (!append) activePage.value = page
    } catch (err: unknown) {
      if (!runner.isCurrent(seq)) return
      if (isAbortError(err)) return
      console.error('Typesense error', err)
      errorMsg.value = (err as Error)?.message || 'Error al buscar.'
      if (!append) { hits.value = []; total.value = 0 }
    } finally {
      if (runner.isCurrent(seq)) {
        runner.settle(seq)
        loading.value = false
        loadingMore.value = false
      }
    }
  }

  function loadMore() {
    if (options.paginationType() !== 'infinite_scroll') return
    if (loadingMore.value || loading.value || !hasMore.value) return
    runSearch(query.value, currentPage.value, true)
  }

  function goToPage(p: number) {
    activePage.value = p
    hits.value = []
    runSearch(query.value, p, false)
  }

  function retry() {
    runSearch(query.value, activePage.value, false)
  }

  onBeforeUnmount(() => runner.dispose())

  watch(debouncedQuery, (q) => {
    hits.value = []
    total.value = 0
    currentPage.value = 1
    activePage.value = 1
    runSearch(q, 1, false)
  })

  watch(exactSearch, () => {
    if (query.value.trim()) runSearch(query.value, 1, false)
  })

  return {
    query, debouncedQuery, loading, loadingMore, errorMsg, exactSearch,
    hits, total, currentPage, activePage, totalPages, hasMore,
    runSearch, loadMore, goToPage, retry
  }
}

// ─── Modo agrupado: párrafos + join a la colección principal (SearchPanel.vue) ─

export interface ParagraphDoc {
  id?: string
  document_id: string
  text: string
  number: number
  locale: string
  type: string
}

export interface TypesenseGroupedParagraphHit {
  document: ParagraphDoc
  highlights?: TypesenseHighlight[]
  highlight?: Record<string, { snippet?: string, value?: string }>
  text_match?: number
}

export interface TypesenseGroupedHit {
  groupKey: string[]
  hits: TypesenseGroupedParagraphHit[]
}

interface GroupedSearchResponse {
  found: number
  groupedHits?: TypesenseGroupedHit[]
  hits?: Array<{ document: Record<string, unknown> }>
}

export interface SearchGroup {
  docId: string
  firstHit: TypesenseGroupedParagraphHit
  allHits: TypesenseGroupedParagraphHit[]
}

export interface BrowseItem {
  docId: string
  meta: CachedDocMeta
}

export interface DisplayGroup {
  docId: string
  meta: CachedDocMeta | undefined
  firstHit: TypesenseGroupedParagraphHit | null
}

export interface GroupedTypesenseSearchOptions {
  paragraphsCollection: string
  mainCollection: string
  groupByField: string
  queryBy: string
  /** Reevaluado en cada request (p.ej. depende de `locale.value`). */
  filterBy: () => string
  /** Cuando devuelve false, se excluyen los documentos `private:=true`. */
  isUnlocked: () => boolean
  pageSize: () => number
  paginationType: () => 'infinite_scroll' | 'numbered'
  initialQuery: string
  initialPage: number
  highlightAffixNumTokens?: number
  timeoutMs?: number
}

const META_FIELDS = 'id,title,date,timestamp,place,city,state,country,type,slug,draft'

export function useGroupedTypesenseSearch(options: GroupedTypesenseSearchOptions) {
  const { documentsApi } = useTypesenseClient()
  const docMetaCache = useDocMetaCache()
  const timeoutMs = options.timeoutMs ?? DEFAULT_TIMEOUT_MS
  const highlightAffixNumTokens = options.highlightAffixNumTokens ?? 15

  const query = ref(options.initialQuery)
  const debouncedQuery = useDebounce(query, 150)
  const loading = ref(false)
  const loadingMore = ref(false)
  const errorMsg = ref<string | null>(null)
  const exactSearch = ref(false)
  const sortMode = ref<'relevance' | 'date'>('relevance')

  const groupedHits = ref<SearchGroup[]>([])
  const total = ref(0)
  const currentPage = ref(1)
  const activePage = ref(options.initialPage)

  const hasMore = computed(() =>
    options.paginationType() === 'infinite_scroll' ? groupedHits.value.length < total.value : false
  )

  const visibleGroupCount = ref(10)
  const visibleGroups = computed(() =>
    options.paginationType() === 'infinite_scroll'
      ? groupedHits.value.slice(0, visibleGroupCount.value)
      : groupedHits.value
  )
  const hasMoreVisible = computed(() =>
    options.paginationType() === 'infinite_scroll' &&
    visibleGroupCount.value < groupedHits.value.length
  )

  const browseItems = ref<BrowseItem[]>([])
  const browseTotal = ref(0)
  const browsePage = ref(1)
  const hasMoreBrowse = computed(() =>
    options.paginationType() === 'infinite_scroll'
      ? browseItems.value.length < browseTotal.value
      : false
  )

  const displayGroups = computed((): DisplayGroup[] => {
    if (!debouncedQuery.value.trim()) {
      return browseItems.value.map(item => ({
        docId: item.docId,
        meta: item.meta,
        firstHit: null
      }))
    }
    return visibleGroups.value.map(g => ({
      docId: g.docId,
      meta: docMetaCache.get(options.mainCollection, g.docId),
      firstHit: g.firstHit
    }))
  })

  const displayTotal = computed(() =>
    debouncedQuery.value.trim() ? total.value : browseTotal.value
  )
  const totalPages = computed(() =>
    Math.max(1, Math.ceil(displayTotal.value / options.pageSize()))
  )

  function cacheParentMeta(newGroups: SearchGroup[]) {
    for (const g of newGroups) {
      if (!g.docId) continue
      const parentMeta = (g.firstHit?.document as unknown as Record<string, unknown>)?.[options.mainCollection] as Partial<CachedDocMeta> | undefined
      if (parentMeta) docMetaCache.set(options.mainCollection, g.docId, { id: g.docId, ...parentMeta } as CachedDocMeta)
    }
  }

  function searchFilterBy() {
    return options.isUnlocked()
      ? options.filterBy()
      : `${options.filterBy()} && $${options.mainCollection}(private:=false)`
  }

  function browseFilterBy() {
    return options.isUnlocked()
      ? options.filterBy()
      : `${options.filterBy()} && private:=false`
  }

  const runner = createAbortableRunner()

  async function runSearch(q: string, page = 1, append = false) {
    const { seq, signal } = runner.start(() => {
      loading.value = false
      loadingMore.value = false
      errorMsg.value = 'La búsqueda tardó demasiado. Inténtalo de nuevo.'
    }, timeoutMs)

    if (append) loadingMore.value = true
    else loading.value = true
    errorMsg.value = null

    const isInfinite = options.paginationType() === 'infinite_scroll'
    const typePage = isInfinite ? (append ? currentPage.value + 1 : 1) : page

    try {
      const shouldSortByDate = sortMode.value === 'date' && q.trim()

      const multi = await documentsApi.multiSearch({
        multiSearchParameters: {},
        multiSearchSearchesParameter: {
          searches: [{
            collection: options.paragraphsCollection,
            q: exactSearch.value && q ? `"${q}"` : q || '*',
            queryBy: options.queryBy,
            filterBy: searchFilterBy(),
            ...(shouldSortByDate ? { sortBy: `$${options.mainCollection}(timestamp:desc)` } : {}),
            perPage: options.pageSize(),
            page: typePage,
            highlightFullFields: options.queryBy,
            highlightFields: options.queryBy,
            highlightStartTag: '<mark class="search-match">',
            highlightEndTag: '</mark>',
            highlightAffixNumTokens,
            groupBy: options.groupByField,
            includeFields: `*, $${options.mainCollection}(${META_FIELDS})`
          }]
        }
      }, { signal })
      if (!runner.isCurrent(seq)) return

      const res = (multi?.results?.[0] ?? {}) as GroupedSearchResponse
      const rawGroups = res?.groupedHits ?? []
      const newGroups: SearchGroup[] = rawGroups.map(g => ({
        docId: g.groupKey[0]!,
        firstHit: g.hits[0]!,
        allHits: g.hits
      }))

      cacheParentMeta(newGroups)

      if (!runner.isCurrent(seq)) return

      groupedHits.value = append ? groupedHits.value.concat(newGroups) : newGroups
      total.value = res?.found ?? groupedHits.value.length
      currentPage.value = typePage
      if (!append) activePage.value = page
    } catch (err: unknown) {
      if (!runner.isCurrent(seq)) return
      if (isAbortError(err)) return
      console.error('Typesense error', err)
      errorMsg.value = (err as Error)?.message || 'Error al buscar.'
      if (!append) { groupedHits.value = []; total.value = 0 }
    } finally {
      if (runner.isCurrent(seq)) {
        runner.settle(seq)
        loading.value = false
        loadingMore.value = false
      }
    }
  }

  async function runBrowse(page = 1, append = false) {
    const { seq, signal } = runner.start(() => {
      loading.value = false
      loadingMore.value = false
      errorMsg.value = 'La búsqueda tardó demasiado. Inténtalo de nuevo.'
    }, timeoutMs)

    if (append) loadingMore.value = true
    else loading.value = true
    errorMsg.value = null

    const isInfinite = options.paginationType() === 'infinite_scroll'
    const typePage = isInfinite ? (append ? browsePage.value + 1 : 1) : page

    try {
      const multi = await documentsApi.multiSearch({
        multiSearchParameters: {},
        multiSearchSearchesParameter: {
          searches: [{
            collection: options.mainCollection,
            q: '*',
            queryBy: 'title',
            filterBy: browseFilterBy(),
            sortBy: 'timestamp:desc',
            perPage: options.pageSize(),
            page: typePage,
            includeFields: META_FIELDS
          }]
        }
      }, { signal })
      if (!runner.isCurrent(seq)) return
      const result = (multi?.results?.[0] as GroupedSearchResponse | undefined)
      const rawHits = result?.hits ?? []
      const newItems = rawHits.map((h) => {
        const meta = h.document as Partial<CachedDocMeta>
        const docId = String(meta.id ?? '')
        return { docId, meta: { id: docId, ...meta } as CachedDocMeta }
      })

      browseItems.value = append ? browseItems.value.concat(newItems) : newItems
      browseTotal.value = result?.found ?? browseItems.value.length
      browsePage.value = typePage
      if (!append) activePage.value = page
    } catch (err: unknown) {
      if (!runner.isCurrent(seq)) return
      if (isAbortError(err)) return
      console.error('Typesense error', err)
      errorMsg.value = (err as Error)?.message || 'Error al buscar.'
      if (!append) { browseItems.value = []; browseTotal.value = 0 }
    } finally {
      if (runner.isCurrent(seq)) {
        runner.settle(seq)
        loading.value = false
        loadingMore.value = false
      }
    }
  }

  function loadMore() {
    if (options.paginationType() !== 'infinite_scroll') return
    if (loadingMore.value || loading.value || !hasMore.value) return
    runSearch(query.value, currentPage.value, true)
  }

  function goToPage(p: number) {
    activePage.value = p
    if (!debouncedQuery.value.trim()) {
      browseItems.value = []
      runBrowse(p, false)
    } else {
      groupedHits.value = []
      runSearch(query.value, p, false)
    }
  }

  function retry() {
    if (!query.value.trim()) runBrowse(activePage.value, false)
    else runSearch(query.value, activePage.value, false)
  }

  onBeforeUnmount(() => runner.dispose())

  watch(debouncedQuery, (q) => {
    activePage.value = 1
    if (!q.trim()) {
      groupedHits.value = []; total.value = 0; currentPage.value = 1; visibleGroupCount.value = 10
      browseItems.value = []; browseTotal.value = 0; browsePage.value = 1
      runBrowse(1, false)
    } else {
      browseItems.value = []; browseTotal.value = 0; browsePage.value = 1
      groupedHits.value = []; total.value = 0; currentPage.value = 1; visibleGroupCount.value = 10
      runSearch(q, 1, false)
    }
  })

  watch(exactSearch, () => {
    if (query.value.trim()) runSearch(query.value, 1, false)
  })

  watch(sortMode, () => {
    if (query.value.trim()) {
      groupedHits.value = []
      total.value = 0
      currentPage.value = 1
      runSearch(query.value, 1, false)
    }
  })

  return {
    query, debouncedQuery, loading, loadingMore, errorMsg,
    exactSearch, sortMode,
    groupedHits, total, currentPage,
    visibleGroupCount, visibleGroups, hasMoreVisible, hasMore,
    browseItems, browseTotal, browsePage, hasMoreBrowse,
    displayGroups, activePage, displayTotal, totalPages,
    runSearch, runBrowse, loadMore, goToPage, retry
  }
}