dify/web/app/components/base/chat/chat/hooks.ts

import {
  useCallback,
  useEffect,
  useRef,
  useState,
} from 'react'
import { useTranslation } from 'react-i18next'
import { produce } from 'immer'
import dayjs from 'dayjs'
import type {
  ChatConfig,
  ChatItem,
  Inputs,
  PromptVariable,
  VisionFile,
} from '../types'
import { useChatContext } from './context'
import { TransferMethod } from '@/types/app'
import { useToastContext } from '@/app/components/base/toast'
import { ssePost } from '@/service/base'
import { replaceStringWithValues } from '@/app/components/app/configuration/prompt-value-panel'
import type { Annotation } from '@/models/log'

type GetAbortController = (abortController: AbortController) => void
type SendCallback = {
  onGetConvesationMessages: (conversationId: string, getAbortController: GetAbortController) => Promise<any>
  onGetSuggestedQuestions?: (responseItemId: string, getAbortController: GetAbortController) => Promise<any>
}

export const useCheckPromptVariables = () => {
  const { t } = useTranslation()
  const { notify } = useToastContext()

  const checkPromptVariables = useCallback((promptVariablesConfig: {
    inputs: Inputs
    promptVariables: PromptVariable[]
  }) => {
    const {
      promptVariables,
      inputs,
    } = promptVariablesConfig
    let hasEmptyInput = ''
    const requiredVars = promptVariables.filter(({ key, name, required, type }) => {
      if (type === 'api')
        return false
      const res = (!key || !key.trim()) || (!name || !name.trim()) || (required || required === undefined || required === null)
      return res
    })

    if (requiredVars?.length) {
      requiredVars.forEach(({ key, name }) => {
        if (hasEmptyInput)
          return

        if (!inputs[key])
          hasEmptyInput = name
      })
    }

    if (hasEmptyInput) {
      notify({ type: 'error', message: t('appDebug.errorMessage.valueOfVarRequired', { key: hasEmptyInput }) })
      return false
    }
  }, [notify, t])

  return checkPromptVariables
}

export const useChat = (
  config: ChatConfig,
  promptVariablesConfig?: {
    inputs: Inputs
    promptVariables: PromptVariable[]
  },
  prevChatList?: ChatItem[],
  stopChat?: (taskId: string) => void,
) => {
  const { t } = useTranslation()
  const { notify } = useToastContext()
  const connversationId = useRef('')
  const hasStopResponded = useRef(false)
  const [isResponsing, setIsResponsing] = useState(false)
  const isResponsingRef = useRef(false)
  const [chatList, setChatList] = useState<ChatItem[]>(prevChatList || [])
  const chatListRef = useRef<ChatItem[]>(prevChatList || [])
  const taskIdRef = useRef('')
  const [suggestedQuestions, setSuggestQuestions] = useState<string[]>([])
  const abortControllerRef = useRef<AbortController | null>(null)
  const conversationMessagesAbortControllerRef = useRef<AbortController | null>(null)
  const suggestedQuestionsAbortControllerRef = useRef<AbortController | null>(null)
  const checkPromptVariables = useCheckPromptVariables()

  const handleUpdateChatList = useCallback((newChatList: ChatItem[]) => {
    setChatList(newChatList)
    chatListRef.current = newChatList
  }, [])
  const handleResponsing = useCallback((isResponsing: boolean) => {
    setIsResponsing(isResponsing)
    isResponsingRef.current = isResponsing
  }, [])

  const getIntroduction = useCallback((str: string) => {
    return replaceStringWithValues(str, promptVariablesConfig?.promptVariables || [], promptVariablesConfig?.inputs || {})
  }, [promptVariablesConfig?.inputs, promptVariablesConfig?.promptVariables])
  useEffect(() => {
    if (config.opening_statement && !chatList.length) {
      handleUpdateChatList([{
        id: `${Date.now()}`,
        content: getIntroduction(config.opening_statement),
        isAnswer: true,
        isOpeningStatement: true,
        suggestedQuestions: config.suggested_questions,
      }])
    }
  }, [
    config.opening_statement,
    config.suggested_questions,
    getIntroduction,
    chatList,
    handleUpdateChatList,
  ])

  const handleStop = useCallback(() => {
    hasStopResponded.current = true
    handleResponsing(false)
    if (stopChat && taskIdRef.current)
      stopChat(taskIdRef.current)
    if (abortControllerRef.current)
      abortControllerRef.current.abort()
    if (conversationMessagesAbortControllerRef.current)
      conversationMessagesAbortControllerRef.current.abort()
    if (suggestedQuestionsAbortControllerRef.current)
      suggestedQuestionsAbortControllerRef.current.abort()
  }, [stopChat, handleResponsing])

  const handleRestart = useCallback(() => {
    handleStop()
    connversationId.current = ''
    const newChatList = config.opening_statement
      ? [{
        id: `${Date.now()}`,
        content: config.opening_statement,
        isAnswer: true,
        isOpeningStatement: true,
        suggestedQuestions: config.suggested_questions,
      }]
      : []
    handleUpdateChatList(newChatList)
    setSuggestQuestions([])
  }, [
    config,
    handleStop,
    handleUpdateChatList,
  ])

  const updateCurrentQA = useCallback(({
    responseItem,
    questionId,
    placeholderAnswerId,
    questionItem,
  }: {
    responseItem: ChatItem
    questionId: string
    placeholderAnswerId: string
    questionItem: ChatItem
  }) => {
    const newListWithAnswer = produce(
      chatListRef.current.filter(item => item.id !== responseItem.id && item.id !== placeholderAnswerId),
      (draft) => {
        if (!draft.find(item => item.id === questionId))
          draft.push({ ...questionItem })

        draft.push({ ...responseItem })
      })
    handleUpdateChatList(newListWithAnswer)
  }, [handleUpdateChatList])

  const handleSend = useCallback(async (
    url: string,
    data: any,
    {
      onGetConvesationMessages,
      onGetSuggestedQuestions,
    }: SendCallback,
  ) => {
    setSuggestQuestions([])
    if (isResponsingRef.current) {
      notify({ type: 'info', message: t('appDebug.errorMessage.waitForResponse') })
      return false
    }

    if (promptVariablesConfig?.inputs && promptVariablesConfig?.promptVariables)
      checkPromptVariables(promptVariablesConfig)

    const questionId = `question-${Date.now()}`
    const questionItem = {
      id: questionId,
      content: data.query,
      isAnswer: false,
      message_files: data.files,
    }

    const placeholderAnswerId = `answer-placeholder-${Date.now()}`
    const placeholderAnswerItem = {
      id: placeholderAnswerId,
      content: '',
      isAnswer: true,
    }

    const newList = [...chatListRef.current, questionItem, placeholderAnswerItem]
    handleUpdateChatList(newList)

    // answer
    const responseItem: ChatItem = {
      id: `${Date.now()}`,
      content: '',
      agent_thoughts: [],
      message_files: [],
      isAnswer: true,
    }

    handleResponsing(true)
    hasStopResponded.current = false

    const bodyParams = {
      response_mode: 'streaming',
      conversation_id: connversationId.current,
      ...data,
    }
    if (bodyParams?.files?.length) {
      bodyParams.files = bodyParams.files.map((item: VisionFile) => {
        if (item.transfer_method === TransferMethod.local_file) {
          return {
            ...item,
            url: '',
          }
        }
        return item
      })
    }

    let isAgentMode = false
    let hasSetResponseId = false

    ssePost(
      url,
      {
        body: bodyParams,
      },
      {
        getAbortController: (abortController) => {
          abortControllerRef.current = abortController
        },
        onData: (message: string, isFirstMessage: boolean, { conversationId: newConversationId, messageId, taskId }: any) => {
          if (!isAgentMode) {
            responseItem.content = responseItem.content + message
          }
          else {
            const lastThought = responseItem.agent_thoughts?.[responseItem.agent_thoughts?.length - 1]
            if (lastThought)
              lastThought.thought = lastThought.thought + message // need immer setAutoFreeze
          }

          if (messageId && !hasSetResponseId) {
            responseItem.id = messageId
            hasSetResponseId = true
          }

          if (isFirstMessage && newConversationId)
            connversationId.current = newConversationId

          taskIdRef.current = taskId
          if (messageId)
            responseItem.id = messageId

          updateCurrentQA({
            responseItem,
            questionId,
            placeholderAnswerId,
            questionItem,
          })
        },
        async onCompleted(hasError?: boolean) {
          handleResponsing(false)

          if (hasError)
            return

          if (connversationId.current && !hasStopResponded.current) {
            const { data }: any = await onGetConvesationMessages(
              connversationId.current,
              newAbortController => conversationMessagesAbortControllerRef.current = newAbortController,
            )
            const newResponseItem = data.find((item: any) => item.id === responseItem.id)
            if (!newResponseItem)
              return

            const newChatList = produce(chatListRef.current, (draft) => {
              const index = draft.findIndex(item => item.id === responseItem.id)
              if (index !== -1) {
                const requestion = draft[index - 1]
                draft[index - 1] = {
                  ...requestion,
                  log: newResponseItem.message,
                }
                draft[index] = {
                  ...draft[index],
                  more: {
                    time: dayjs.unix(newResponseItem.created_at).format('hh:mm A'),
                    tokens: newResponseItem.answer_tokens + newResponseItem.message_tokens,
                    latency: newResponseItem.provider_response_latency.toFixed(2),
                  },
                }
              }
            })
            handleUpdateChatList(newChatList)
          }
          if (config.suggested_questions_after_answer?.enabled && !hasStopResponded.current && onGetSuggestedQuestions) {
            const { data }: any = await onGetSuggestedQuestions(
              responseItem.id,
              newAbortController => suggestedQuestionsAbortControllerRef.current = newAbortController,
            )
            setSuggestQuestions(data)
          }
        },
        onFile(file) {
          const lastThought = responseItem.agent_thoughts?.[responseItem.agent_thoughts?.length - 1]
          if (lastThought)
            responseItem.agent_thoughts![responseItem.agent_thoughts!.length - 1].message_files = [...(lastThought as any).message_files, file]

          updateCurrentQA({
            responseItem,
            questionId,
            placeholderAnswerId,
            questionItem,
          })
        },
        onThought(thought) {
          isAgentMode = true
          const response = responseItem as any
          if (thought.message_id && !hasSetResponseId)
            response.id = thought.message_id
          if (response.agent_thoughts.length === 0) {
            response.agent_thoughts.push(thought)
          }
          else {
            const lastThought = response.agent_thoughts[response.agent_thoughts.length - 1]
            // thought changed but still the same thought, so update.
            if (lastThought.id === thought.id) {
              thought.thought = lastThought.thought
              thought.message_files = lastThought.message_files
              responseItem.agent_thoughts![response.agent_thoughts.length - 1] = thought
            }
            else {
              responseItem.agent_thoughts!.push(thought)
            }
          }
          updateCurrentQA({
            responseItem,
            questionId,
            placeholderAnswerId,
            questionItem,
          })
        },
        onMessageEnd: (messageEnd) => {
          if (messageEnd.metadata?.annotation_reply) {
            responseItem.id = messageEnd.id
            responseItem.annotation = ({
              id: messageEnd.metadata.annotation_reply.id,
              authorName: messageEnd.metadata.annotation_reply.account.name,
            })
            const baseState = chatListRef.current.filter(item => item.id !== responseItem.id && item.id !== placeholderAnswerId)
            const newListWithAnswer = produce(
              baseState,
              (draft) => {
                if (!draft.find(item => item.id === questionId))
                  draft.push({ ...questionItem })

                draft.push({
                  ...responseItem,
                })
              })
            handleUpdateChatList(newListWithAnswer)
            return
          }
          responseItem.citation = messageEnd.metadata?.retriever_resources || []

          const newListWithAnswer = produce(
            chatListRef.current.filter(item => item.id !== responseItem.id && item.id !== placeholderAnswerId),
            (draft) => {
              if (!draft.find(item => item.id === questionId))
                draft.push({ ...questionItem })

              draft.push({ ...responseItem })
            })
          handleUpdateChatList(newListWithAnswer)
        },
        onMessageReplace: (messageReplace) => {
          responseItem.content = messageReplace.answer
        },
        onError() {
          handleResponsing(false)
          const newChatList = produce(chatListRef.current, (draft) => {
            draft.splice(draft.findIndex(item => item.id === placeholderAnswerId), 1)
          })
          handleUpdateChatList(newChatList)
        },
      })
    return true
  }, [
    checkPromptVariables,
    config.suggested_questions_after_answer,
    updateCurrentQA,
    t,
    notify,
    promptVariablesConfig,
    handleUpdateChatList,
    handleResponsing,
  ])

  const handleAnnotationEdited = useCallback((query: string, answer: string, index: number) => {
    setChatList(chatListRef.current.map((item, i) => {
      if (i === index - 1) {
        return {
          ...item,
          content: query,
        }
      }
      if (i === index) {
        return {
          ...item,
          content: answer,
          annotation: {
            ...item.annotation,
            logAnnotation: undefined,
          } as any,
        }
      }
      return item
    }))
  }, [])
  const handleAnnotationAdded = useCallback((annotationId: string, authorName: string, query: string, answer: string, index: number) => {
    setChatList(chatListRef.current.map((item, i) => {
      if (i === index - 1) {
        return {
          ...item,
          content: query,
        }
      }
      if (i === index) {
        const answerItem = {
          ...item,
          content: item.content,
          annotation: {
            id: annotationId,
            authorName,
            logAnnotation: {
              content: answer,
              account: {
                id: '',
                name: authorName,
                email: '',
              },
            },
          } as Annotation,
        }
        return answerItem
      }
      return item
    }))
  }, [])
  const handleAnnotationRemoved = useCallback((index: number) => {
    setChatList(chatListRef.current.map((item, i) => {
      if (i === index) {
        return {
          ...item,
          content: item.content,
          annotation: {
            ...(item.annotation || {}),
            id: '',
          } as Annotation,
        }
      }
      return item
    }))
  }, [])

  return {
    chatList,
    setChatList,
    conversationId: connversationId.current,
    isResponsing,
    setIsResponsing,
    handleSend,
    suggestedQuestions,
    handleRestart,
    handleStop,
    handleAnnotationEdited,
    handleAnnotationAdded,
    handleAnnotationRemoved,
  }
}

export const useCurrentAnswerIsResponsing = (answerId: string) => {
  const {
    isResponsing,
    chatList,
  } = useChatContext()

  const isLast = answerId === chatList[chatList.length - 1]?.id

  return isLast && isResponsing
}