import { computed, nextTick, onBeforeUnmount, onMounted, ref, watch } from 'vue'

import ConfirmDialog from '../../components/shared/ConfirmDialog.vue'
import { useSystemState } from '../../composables/useSystemState.js'
import { useToast } from '../../composables/useToast.js'
import {
  deleteKnowledgeDocument,
  fetchKnowledgeDocument,
  fetchKnowledgeDocumentBlob,
  fetchLlmWikiDocumentDetail,
  fetchKnowledgeLibrary,
  fetchKnowledgeOnlyOfficeConfig,
  syncKnowledgeDocumentToLlmWiki,
  updateLlmWikiDocumentSummary,
  uploadKnowledgeDocument
} from '../../services/knowledge.js'
import { loadOnlyOfficeApi } from '../../services/onlyoffice.js'
import { isManagerUser } from '../../utils/accessControl.js'
import {
  buildExcelPreviewTable,
  buildPreviewMetaLine,
  buildPreviewSecondaryMetaLine
} from './policiesPreviewFormatters.js'
import {
  canUseOnlyOfficePreview,
  resolveKnowledgePreviewMode,
  shouldRenderOnlyOfficeHost,
  shouldRenderOnlyOfficePreview
} from './knowledgePreviewMode.js'
import { resolveKnowledgePreviewLayoutState } from './knowledgePreviewLayout.js'
import { resolveInitialKnowledgeFolder } from './knowledgeFolderSelection.js'
import { buildOnlyOfficePreviewConfig } from './onlyOfficePreviewConfig.js'

function triggerFileDownload(blob, filename) {
  const url = URL.createObjectURL(blob)
  const anchor = document.createElement('a')
  anchor.href = url
  anchor.download = filename
  anchor.click()
  URL.revokeObjectURL(url)
}

let bodyOverflowSnapshot = ''
let bodyOverscrollBehaviorSnapshot = ''

function setBodyScrollLocked(isLocked) {
  if (typeof document === 'undefined') {
    return
  }

  const { body } = document
  if (!body) {
    return
  }

  if (isLocked) {
    if (body.dataset.knowledgePreviewLocked === 'true') {
      return
    }

    bodyOverflowSnapshot = body.style.overflow
    bodyOverscrollBehaviorSnapshot = body.style.overscrollBehavior
    body.style.overflow = 'hidden'
    body.style.overscrollBehavior = 'contain'
    body.dataset.knowledgePreviewLocked = 'true'
    return
  }

  if (body.dataset.knowledgePreviewLocked !== 'true') {
    return
  }

  body.style.overflow = bodyOverflowSnapshot
  body.style.overscrollBehavior = bodyOverscrollBehaviorSnapshot
  delete body.dataset.knowledgePreviewLocked
  bodyOverflowSnapshot = ''
  bodyOverscrollBehaviorSnapshot = ''
}

export default {
  name: 'PoliciesView',
  components: {
    ConfirmDialog
  },
  emits: ['summary-change'],
  setup(_, { emit }) {
    const { currentUser } = useSystemState()
    const { toast } = useToast()

    const documentSearch = ref('')
    const activeFolder = ref('')
    const folders = ref([])
    const documents = ref([])
    const selectedDocument = ref(null)
    const pageSizeOpen = ref(false)
    const currentPage = ref(1)
    const pageSize = ref(10)
    const pageSizes = [10, 20, 50]
    const loading = ref(false)
    const uploadInput = ref(null)
    const uploading = ref(false)
    const deletingId = ref('')
    const ingestingId = ref('')
    const deleteDialogOpen = ref(false)
    const deleteTargetDocument = ref(null)
    const previewLoading = ref(false)
    const previewBlobUrl = ref('')
    const previewError = ref('')
    const onlyOfficeLoading = ref(false)
    const onlyOfficeError = ref('')
    const onlyOfficeAvailable = ref(false)
    const onlyOfficeEditor = ref(null)
    const onlyOfficeHostId = ref('knowledge-onlyoffice-preview')
    const onlyOfficeReadyTimeoutId = ref(0)
    const currentPreviewPageIndex = ref(0)
    const previewDialogPanel = ref(null)
    const llmWikiDialogOpen = ref(false)
    const llmWikiDialogPanel = ref(null)
    const llmWikiLoading = ref(false)
    const llmWikiSaving = ref(false)
    const llmWikiError = ref('')
    const llmWikiDocument = ref(null)
    const llmWikiSummaryDraft = ref('')

    const isAdmin = computed(() => isManagerUser(currentUser.value))
    const uploadHint = computed(() =>
      isAdmin.value
        ? '支持 PDF / Word / Excel / PPT / 图片 / 文本文件，重复同名文件将自动覆盖并升级版本'
        : '当前账号只有查阅权限，上传、删除和修改仅管理员可用'
    )

    const filteredFolders = computed(() => folders.value)

    const filteredDocuments = computed(() => {
      const key = documentSearch.value.trim()

      return documents.value.filter((doc) => {
        const inFolder = activeFolder.value ? doc.folder === activeFolder.value : true
        const matchesSearch = key ? doc.name.includes(key) : true
        return inFolder && matchesSearch
      })
    })

    const totalCount = computed(() => filteredDocuments.value.length)
    const totalPages = computed(() => Math.max(1, Math.ceil(totalCount.value / pageSize.value)))
    const visibleDocuments = computed(() => {
      const start = (currentPage.value - 1) * pageSize.value
      return filteredDocuments.value.slice(start, start + pageSize.value)
    })
    const activePreviewPage = computed(() => {
      const pages = selectedDocument.value?.previewPages || []
      return pages[currentPreviewPageIndex.value] || pages[0] || null
    })
    const previewMetaLine = computed(() => buildPreviewMetaLine(selectedDocument.value))
    const previewSecondaryMetaLine = computed(() =>
      buildPreviewSecondaryMetaLine(selectedDocument.value, activePreviewPage.value)
    )
    const previewLayoutState = computed(() =>
      resolveKnowledgePreviewLayoutState(selectedDocument.value)
    )
    const previewMode = computed(() =>
      resolveKnowledgePreviewMode(selectedDocument.value, {
        onlyOfficeAvailable: onlyOfficeAvailable.value
      })
    )
    const shouldRenderOnlyOffice = computed(() =>
      shouldRenderOnlyOfficePreview(selectedDocument.value, {
        onlyOfficeLoading: onlyOfficeLoading.value,
        onlyOfficeAvailable: onlyOfficeAvailable.value,
        onlyOfficeError: onlyOfficeError.value
      })
    )
    const shouldRenderOnlyOfficeHostNode = computed(() =>
      shouldRenderOnlyOfficeHost(selectedDocument.value, {
        onlyOfficeLoading: onlyOfficeLoading.value,
        onlyOfficeAvailable: onlyOfficeAvailable.value,
        onlyOfficeError: onlyOfficeError.value
      })
    )
    const excelPreviewTable = computed(() =>
      selectedDocument.value?.previewKind === 'table'
        ? buildExcelPreviewTable(activePreviewPage.value)
        : { headers: [], rows: [] }
    )

    function revokePreviewBlob() {
      if (previewBlobUrl.value) {
        URL.revokeObjectURL(previewBlobUrl.value)
        previewBlobUrl.value = ''
      }
    }

    function destroyOnlyOfficeEditor() {
      if (onlyOfficeReadyTimeoutId.value) {
        window.clearTimeout(onlyOfficeReadyTimeoutId.value)
        onlyOfficeReadyTimeoutId.value = 0
      }
      if (onlyOfficeEditor.value?.destroyEditor) {
        onlyOfficeEditor.value.destroyEditor()
      }
      onlyOfficeEditor.value = null
    }

    async function mountOnlyOfficeEditor(documentId) {
      onlyOfficeLoading.value = true
      onlyOfficeError.value = ''
      onlyOfficeAvailable.value = false
      destroyOnlyOfficeEditor()

      try {
        const payload = await fetchKnowledgeOnlyOfficeConfig(documentId)
        await loadOnlyOfficeApi(payload.documentServerUrl)
        await nextTick()

        if (!window.DocsAPI?.DocEditor) {
          throw new Error('ONLYOFFICE 编辑器未正确加载。')
        }

        onlyOfficeHostId.value = `knowledge-onlyoffice-preview-${documentId}`
        await nextTick()
        const config = buildOnlyOfficePreviewConfig(payload.config, {
          viewportHeight: window.innerHeight
        })
        const upstreamEvents = config.events || {}
        config.events = {
          ...upstreamEvents,
          onAppReady(event) {
            if (onlyOfficeReadyTimeoutId.value) {
              window.clearTimeout(onlyOfficeReadyTimeoutId.value)
              onlyOfficeReadyTimeoutId.value = 0
            }
            onlyOfficeAvailable.value = true
            onlyOfficeLoading.value = false
            upstreamEvents.onAppReady?.(event)
          },
          onError(event) {
            if (onlyOfficeReadyTimeoutId.value) {
              window.clearTimeout(onlyOfficeReadyTimeoutId.value)
              onlyOfficeReadyTimeoutId.value = 0
            }
            const errorCode = event?.data?.errorCode
            const errorDescription = event?.data?.errorDescription
            const message = errorDescription
              ? `ONLYOFFICE 预览失败：${errorDescription}`
              : `ONLYOFFICE 预览失败${errorCode ? `（错误码 ${errorCode}）` : '。'}`
            onlyOfficeError.value = message
            onlyOfficeLoading.value = false
            console.error('ONLYOFFICE onError', event)
            toast(message)
            upstreamEvents.onError?.(event)
          }
        }
        onlyOfficeEditor.value = new window.DocsAPI.DocEditor(onlyOfficeHostId.value, config)
        onlyOfficeReadyTimeoutId.value = window.setTimeout(() => {
          if (!onlyOfficeAvailable.value && !onlyOfficeError.value) {
            onlyOfficeError.value = 'ONLYOFFICE 预览初始化超时。请检查浏览器是否拦截了 iframe 或混合内容。'
            onlyOfficeLoading.value = false
            toast(onlyOfficeError.value)
          }
        }, 10000)
        return true
      } catch (error) {
        onlyOfficeError.value = error.message || 'ONLYOFFICE 预览加载失败。'
        toast(onlyOfficeError.value)
        return false
      } finally {
        if (onlyOfficeError.value) {
          onlyOfficeLoading.value = false
        }
      }
    }

    async function loadLibrary(options = {}) {
      loading.value = true
      try {
        const payload = await fetchKnowledgeLibrary()
        folders.value = payload.folders || []
        documents.value = payload.documents || []
        emit('summary-change', { totalDocuments: documents.value.length })

        activeFolder.value = resolveInitialKnowledgeFolder(folders.value, activeFolder.value)

        if (options.preserveSelection && selectedDocument.value?.id) {
          const exists = documents.value.some((doc) => doc.id === selectedDocument.value.id)
          if (!exists) {
            closePreview()
          }
        }
        if (options.preserveSelection && llmWikiDocument.value?.document_id) {
          const exists = documents.value.some((doc) => doc.id === llmWikiDocument.value.document_id)
          if (!exists) {
            closeLlmWikiSummary()
          }
        }
      } catch (error) {
        emit('summary-change', { totalDocuments: 0 })
        toast(error.message || '知识库加载失败。')
      } finally {
        loading.value = false
      }
    }

    async function selectDocument(documentId) {
      previewLoading.value = true
      previewError.value = ''
      onlyOfficeError.value = ''
      onlyOfficeAvailable.value = false
      revokePreviewBlob()
      destroyOnlyOfficeEditor()

      try {
        const payload = await fetchKnowledgeDocument(documentId)
        selectedDocument.value = payload
        currentPreviewPageIndex.value = 0

        if (canUseOnlyOfficePreview(payload)) {
          previewLoading.value = false
          await mountOnlyOfficeEditor(documentId)
          return
        }

        if (payload.previewKind === 'pdf' || payload.previewKind === 'image') {
          const blob = await fetchKnowledgeDocumentBlob(documentId, 'inline')
          previewBlobUrl.value = URL.createObjectURL(blob)
        }
      } catch (error) {
        previewError.value = error.message || '预览加载失败。'
        toast(previewError.value)
      } finally {
        previewLoading.value = false
      }
    }

    async function handleDownload(document) {
      try {
        const blob = await fetchKnowledgeDocumentBlob(document.id, 'attachment')
        triggerFileDownload(blob, document.name)
      } catch (error) {
        toast(error.message || '下载失败。')
      }
    }

    function patchDocumentState(documentId, patch) {
      documents.value = documents.value.map((doc) =>
        doc.id === documentId ? { ...doc, ...patch } : doc
      )

      if (selectedDocument.value?.id === documentId) {
        selectedDocument.value = {
          ...selectedDocument.value,
          ...patch
        }
      }
    }

    function resolveIngestActionLabel(document) {
      if (ingestingId.value === document.id) {
        return '归纳中'
      }
      return Number(document?.stateCode || 0) === 3 ? '重新归纳' : '归纳'
    }

    function resolveIngestActionTitle(document) {
      const action = resolveIngestActionLabel(document)
      if (action === '归纳中') {
        return 'Hermes 正在将当前文档归纳到 LLM Wiki'
      }
      if (action === '重新归纳') {
        return '重新使用 Hermes 归纳当前文档到 LLM Wiki'
      }
      return '使用 Hermes 归纳当前文档到 LLM Wiki'
    }

    function canViewLlmWiki(document) {
      return isAdmin.value && Number(document?.stateCode || 0) === 3
    }

    function resolveViewLlmWikiTitle(document) {
      if (!isAdmin.value) {
        return '仅管理员可查看 LLM Wiki 归纳内容'
      }
      if (Number(document?.stateCode || 0) === 2) {
        return 'Hermes 正在归纳当前文档，完成后可查看 LLM Wiki 知识总结'
      }
      if (Number(document?.stateCode || 0) === 4) {
        return '当前文档上次归纳失败，请重新归纳后再查看'
      }
      if (Number(document?.stateCode || 0) !== 3) {
        return '文档尚未完成归纳，暂无可查看的 LLM Wiki 知识总结'
      }
      return '查看并编辑当前文档的 LLM Wiki 归纳内容'
    }

    async function handleManualIngest(document) {
      if (!isAdmin.value || ingestingId.value || !document?.id) {
        return
      }

      ingestingId.value = document.id
      patchDocumentState(document.id, {
        stateCode: 2,
        state: '正归纳',
        stateTone: 'warning'
      })

      try {
        const payload = await syncKnowledgeDocumentToLlmWiki({
          folder: document.folder,
          documentId: document.id
        })
        await loadLibrary({ preserveSelection: true })
        if (selectedDocument.value?.id === document.id) {
          await selectDocument(document.id)
        }
        toast(payload.summary || 'Hermes 已完成文档归纳。')
      } catch (error) {
        patchDocumentState(document.id, {
          stateCode: 4,
          state: '归纳失败',
          stateTone: 'danger'
        })
        toast(error.message || 'Hermes 归纳文档失败。')
      } finally {
        ingestingId.value = ''
      }
    }

    async function openLlmWikiSummary(document) {
      if (!canViewLlmWiki(document) || llmWikiLoading.value || !document?.id) {
        return
      }

      llmWikiDialogOpen.value = true
      llmWikiLoading.value = true
      llmWikiError.value = ''
      llmWikiDocument.value = null
      llmWikiSummaryDraft.value = ''

      try {
        const payload = await fetchLlmWikiDocumentDetail(document.id)
        llmWikiDocument.value = payload
        llmWikiSummaryDraft.value = payload.knowledge_summary_markdown || ''
        await nextTick()
        llmWikiDialogPanel.value?.focus?.()
      } catch (error) {
        llmWikiError.value = error.message || 'LLM Wiki 归纳内容加载失败。'
        toast(llmWikiError.value)
      } finally {
        llmWikiLoading.value = false
      }
    }

    function closeLlmWikiSummary() {
      if (llmWikiSaving.value) {
        return
      }

      llmWikiDialogOpen.value = false
      llmWikiLoading.value = false
      llmWikiError.value = ''
      llmWikiDocument.value = null
      llmWikiSummaryDraft.value = ''
    }

    async function saveLlmWikiSummary() {
      if (!isAdmin.value || !llmWikiDocument.value?.document_id || llmWikiSaving.value) {
        return
      }

      const summaryText = String(llmWikiSummaryDraft.value || '').trim()
      if (!summaryText) {
        toast('知识总结不能为空。')
        return
      }

      llmWikiSaving.value = true
      try {
        const payload = await updateLlmWikiDocumentSummary(llmWikiDocument.value.document_id, {
          knowledge_summary_markdown: summaryText
        })
        llmWikiDocument.value = payload
        llmWikiError.value = ''
        llmWikiSummaryDraft.value = payload.knowledge_summary_markdown || summaryText
        toast('LLM Wiki 知识总结已保存。')
      } catch (error) {
        toast(error.message || 'LLM Wiki 知识总结保存失败。')
      } finally {
        llmWikiSaving.value = false
      }
    }

    function triggerUpload() {
      if (!isAdmin.value || uploading.value) {
        return
      }
      uploadInput.value?.click()
    }

    async function uploadFiles(fileList) {
      const files = Array.from(fileList || []).filter(Boolean)
      if (!files.length || !activeFolder.value || !isAdmin.value) {
        return
      }

      uploading.value = true
      try {
        let latestDocumentId = ''
        for (const file of files) {
          const payload = await uploadKnowledgeDocument({ folder: activeFolder.value, file })
          latestDocumentId = payload.id
        }

        await loadLibrary({ preserveSelection: true })
        toast(files.length > 1 ? `已上传 ${files.length} 个知识库文件。` : '知识库文件已上传。')

        if (latestDocumentId) {
          await selectDocument(latestDocumentId)
        }
      } catch (error) {
        toast(error.message || '上传失败。')
      } finally {
        uploading.value = false
        if (uploadInput.value) {
          uploadInput.value.value = ''
        }
      }
    }

    async function handleFileInput(event) {
      await uploadFiles(event.target.files)
    }

    async function handleDrop(event) {
      if (!isAdmin.value) {
        return
      }
      await uploadFiles(event.dataTransfer?.files)
    }

    async function handleDelete(document) {
      if (!isAdmin.value || deletingId.value) {
        return
      }

      deleteTargetDocument.value = document
      deleteDialogOpen.value = true
    }

    function closeDeleteDialog() {
      if (deletingId.value) {
        return
      }

      deleteDialogOpen.value = false
      deleteTargetDocument.value = null
    }

    async function confirmDeleteDocument() {
      const document = deleteTargetDocument.value
      if (!document || !isAdmin.value || deletingId.value) {
        return
      }

      deletingId.value = document.id
      try {
        await deleteKnowledgeDocument(document.id)
        deleteDialogOpen.value = false
        deleteTargetDocument.value = null
        if (selectedDocument.value?.id === document.id) {
          closePreview()
        }
        if (llmWikiDocument.value?.document_id === document.id) {
          closeLlmWikiSummary()
        }
        await loadLibrary()
        toast('知识库文件已删除。')
      } catch (error) {
        toast(error.message || '删除失败。')
      } finally {
        deletingId.value = ''
      }
    }

    function changePageSize(size) {
      pageSize.value = size
      pageSizeOpen.value = false
      currentPage.value = 1
    }

    function closePreview() {
      selectedDocument.value = null
      previewLoading.value = false
      previewError.value = ''
      currentPreviewPageIndex.value = 0
      revokePreviewBlob()
      destroyOnlyOfficeEditor()
      onlyOfficeLoading.value = false
      onlyOfficeError.value = ''
      onlyOfficeAvailable.value = false
    }

    function handleWindowKeydown(event) {
      if (event.key === 'Escape' && llmWikiDialogOpen.value) {
        closeLlmWikiSummary()
        return
      }
      if (event.key === 'Escape' && selectedDocument.value) {
        closePreview()
      }
    }

    function selectPreviewPage(index) {
      currentPreviewPageIndex.value = index
    }

    watch(filteredDocuments, () => {
      currentPage.value = 1
      pageSizeOpen.value = false

      if (selectedDocument.value && !filteredDocuments.value.some((doc) => doc.id === selectedDocument.value.id)) {
        closePreview()
      }
    })

    watch(activeFolder, () => {
      closePreview()
      closeLlmWikiSummary()
    })

    watch(
      () => previewLayoutState.value.isPreviewModalOpen || llmWikiDialogOpen.value,
      async (isAnyOverlayOpen) => {
        setBodyScrollLocked(isAnyOverlayOpen)

        if (llmWikiDialogOpen.value) {
          await nextTick()
          llmWikiDialogPanel.value?.focus?.()
          return
        }

        if (previewLayoutState.value.isPreviewModalOpen) {
          await nextTick()
          previewDialogPanel.value?.focus?.()
        }
      }
    )

    onMounted(() => {
      loadLibrary()
      window.addEventListener('keydown', handleWindowKeydown)
    })

    onBeforeUnmount(() => {
      revokePreviewBlob()
      destroyOnlyOfficeEditor()
      setBodyScrollLocked(false)
      window.removeEventListener('keydown', handleWindowKeydown)
    })

    return {
      activeFolder,
      activePreviewPage,
      changePageSize,
      closePreview,
      closeDeleteDialog,
      closeLlmWikiSummary,
      canViewLlmWiki,
      confirmDeleteDocument,
      excelPreviewTable,
      currentPage,
      currentPreviewPageIndex,
      deleteDialogOpen,
      deleteTargetDocument,
      deletingId,
      documentSearch,
      filteredFolders,
      handleDelete,
      handleDownload,
      handleDrop,
      handleFileInput,
      handleManualIngest,
      ingestingId,
      isAdmin,
      llmWikiDialogOpen,
      llmWikiDialogPanel,
      llmWikiDocument,
      llmWikiError,
      llmWikiLoading,
      llmWikiSaving,
      llmWikiSummaryDraft,
      loading,
      openLlmWikiSummary,
      pageSize,
      pageSizeOpen,
      pageSizes,
      onlyOfficeError,
      onlyOfficeHostId,
      onlyOfficeLoading,
      previewDialogPanel,
      previewLayoutState,
      previewMode,
      previewMetaLine,
      previewSecondaryMetaLine,
      previewBlobUrl,
      previewError,
      previewLoading,
      shouldRenderOnlyOffice,
      shouldRenderOnlyOfficeHostNode,
      selectDocument,
      selectPreviewPage,
      selectedDocument,
      resolveIngestActionLabel,
      resolveIngestActionTitle,
      resolveViewLlmWikiTitle,
      saveLlmWikiSummary,
      totalCount,
      totalPages,
      triggerUpload,
      uploadHint,
      uploadInput,
      uploading,
      visibleDocuments
    }
  }
}