bot/packages/forge/blocks/difyAi/actions/createChatMessage.ts

import { createAction, option } from '@typebot.io/forge'
import { isDefined, isEmpty, isNotEmpty } from '@typebot.io/lib'
import { auth } from '../auth'
import { defaultBaseUrl } from '../constants'
import { Chunk } from '../types'
import ky, { HTTPError } from 'ky'
import { deprecatedCreateChatMessageOptions } from '../deprecated'

export const createChatMessage = createAction({
  auth,
  name: 'Create Chat Message',
  options: option
    .object({
      query: option.string.layout({
        label: 'Query',
        placeholder: 'User input/question content',
        inputType: 'textarea',
        isRequired: true,
      }),

      conversationVariableId: option.string.layout({
        label: 'Conversation ID',
        moreInfoTooltip:
          'Used to remember the conversation with the user. If empty, a new conversation ID is created.',
        inputType: 'variableDropdown',
      }),
      user: option.string.layout({
        label: 'User',
        moreInfoTooltip:
          'The user identifier, defined by the developer, must ensure uniqueness within the app.',
      }),
      inputs: option
        .array(
          option.object({
            key: option.string.layout({
              label: 'Key',
            }),
            value: option.string.layout({
              label: 'Value',
            }),
          })
        )
        .layout({
          accordion: 'Inputs',
        }),
      responseMapping: option
        .saveResponseArray(
          ['Answer', 'Conversation ID', 'Total Tokens'] as const,
          {
            item: {
              hiddenItems: ['Conversation ID'],
            },
          }
        )
        .layout({
          accordion: 'Save response',
        }),
    })
    .merge(deprecatedCreateChatMessageOptions),
  getSetVariableIds: ({ responseMapping }) =>
    responseMapping?.map((r) => r.variableId).filter(isDefined) ?? [],
  run: {
    stream: {
      getStreamVariableId: ({ responseMapping }) =>
        responseMapping?.find((r) => !r.item || r.item === 'Answer')
          ?.variableId,
      run: async ({
        credentials: { apiEndpoint, apiKey },
        options: {
          conversation_id,
          conversationVariableId,
          query,
          user,
          inputs,
          responseMapping,
        },
        variables,
      }) => {
        const existingDifyConversationId = conversationVariableId
          ? variables.get(conversationVariableId)
          : conversation_id
        try {
          const response = await ky(
            (apiEndpoint ?? defaultBaseUrl) + '/v1/chat-messages',
            {
              method: 'POST',
              headers: {
                Authorization: `Bearer ${apiKey}`,
                'Content-Type': 'application/json',
              },
              body: JSON.stringify({
                inputs:
                  inputs?.reduce((acc, { key, value }) => {
                    if (isEmpty(key) || isEmpty(value)) return acc
                    return {
                      ...acc,
                      [key]: value,
                    }
                  }, {}) ?? {},
                query,
                response_mode: 'streaming',
                conversation_id: existingDifyConversationId,
                user,
                files: [],
              }),
            }
          )
          const reader = response.body?.getReader()

          if (!reader) return {}

          return {
            stream: new ReadableStream({
              async start(controller) {
                try {
                  await processDifyStream(reader, {
                    onDone: () => {
                      controller.close()
                    },
                    onMessage: (message) => {
                      controller.enqueue(
                        new TextEncoder().encode(
                          '0:"' + message.replace(/"/g, '\\"') + '"\n'
                        )
                      )
                    },
                    onMessageEnd({ totalTokens, conversationId }) {
                      if (
                        conversationVariableId &&
                        isNotEmpty(conversationId) &&
                        isEmpty(existingDifyConversationId?.toString())
                      )
                        variables.set(conversationVariableId, conversationId)

                      if ((responseMapping?.length ?? 0) === 0) return
                      responseMapping?.forEach((mapping) => {
                        if (!mapping.variableId) return

                        if (
                          mapping.item === 'Conversation ID' &&
                          isNotEmpty(conversationId) &&
                          isEmpty(existingDifyConversationId?.toString())
                        )
                          variables.set(mapping.variableId, conversationId)

                        if (mapping.item === 'Total Tokens')
                          variables.set(mapping.variableId, totalTokens)
                      })
                    },
                  })
                } catch (e) {
                  console.error(e)
                  controller.error(e) // Properly closing the stream with an error
                }
              },
            }),
          }
        } catch (err) {
          if (err instanceof HTTPError) {
            return {
              httpError: {
                status: err.response.status,
                message: await err.response.text(),
              },
            }
          }
          console.error(err)
          return {}
        }
      },
    },
    server: async ({
      credentials: { apiEndpoint, apiKey },
      options: {
        conversationVariableId,
        conversation_id,
        query,
        user,
        inputs,
        responseMapping,
      },
      variables,
      logs,
    }) => {
      const existingDifyConversationId = conversationVariableId
        ? variables.get(conversationVariableId)
        : conversation_id
      try {
        const response = await ky(
          (apiEndpoint ?? defaultBaseUrl) + '/v1/chat-messages',
          {
            method: 'POST',
            headers: {
              Authorization: `Bearer ${apiKey}`,
              'Content-Type': 'application/json',
            },
            body: JSON.stringify({
              inputs:
                inputs?.reduce((acc, { key, value }) => {
                  if (isEmpty(key) || isEmpty(value)) return acc
                  return {
                    ...acc,
                    [key]: value,
                  }
                }, {}) ?? {},
              query,
              response_mode: 'streaming',
              conversation_id: existingDifyConversationId,
              user,
              files: [],
            }),
          }
        )

        const reader = response.body?.getReader()

        if (!reader)
          return logs.add({
            status: 'error',
            description: 'Failed to read response stream',
          })

        const { answer, conversationId, totalTokens } = await new Promise<{
          answer: string
          conversationId: string | undefined
          totalTokens: number | undefined
        }>(async (resolve, reject) => {
          let answer = ''
          let conversationId: string | undefined
          let totalTokens: number | undefined

          try {
            await processDifyStream(reader, {
              onMessage: (message) => {
                answer += message
              },
              onMessageEnd: ({ totalTokens: tokens, conversationId: id }) => {
                totalTokens = tokens
                conversationId = id
              },
              onDone: () => {
                resolve({ answer, conversationId, totalTokens })
              },
            })
          } catch (e) {
            reject(e)
          }
        })

        if (
          conversationVariableId &&
          isNotEmpty(conversationId) &&
          isEmpty(existingDifyConversationId?.toString())
        )
          variables.set(conversationVariableId, conversationId)

        responseMapping?.forEach((mapping) => {
          if (!mapping.variableId) return

          const item = mapping.item ?? 'Answer'
          if (item === 'Answer')
            variables.set(mapping.variableId, convertNonMarkdownLinks(answer))

          if (
            item === 'Conversation ID' &&
            isNotEmpty(conversationId) &&
            isEmpty(existingDifyConversationId?.toString())
          )
            variables.set(mapping.variableId, conversationId)

          if (item === 'Total Tokens')
            variables.set(mapping.variableId, totalTokens)
        })
      } catch (err) {
        if (err instanceof HTTPError) {
          return logs.add({
            status: 'error',
            description: err.message,
            details: await err.response.text(),
          })
        }
        console.error(err)
      }
    },
  },
})

const convertNonMarkdownLinks = (text: string) => {
  const nonMarkdownLinks = /(?<![\([])https?:\/\/\S+/g
  return text.replace(nonMarkdownLinks, (match) => `[${match}](${match})`)
}

const processDifyStream = async (
  reader: ReadableStreamDefaultReader<Uint8Array>,
  callbacks: {
    onDone: () => void
    onMessage: (message: string) => void
    onMessageEnd?: ({
      totalTokens,
      conversationId,
    }: {
      totalTokens: number
      conversationId: string
    }) => void
  }
) => {
  let jsonChunk = ''

  while (true) {
    const { value, done } = await reader.read()
    if (done) {
      callbacks.onDone()
      return
    }

    const chunk = new TextDecoder().decode(value)

    const lines = chunk.toString().split('\n') as string[]
    lines
      .filter((line) => line.length > 0 && line !== '\n')
      .forEach((line) => {
        jsonChunk += line
        if (jsonChunk.startsWith('event: ')) {
          jsonChunk = ''
          return
        }
        if (!jsonChunk.startsWith('data: ') || !jsonChunk.endsWith('}')) return

        const data = JSON.parse(jsonChunk.slice(6)) as Chunk
        jsonChunk = ''
        if (data.event === 'message' || data.event === 'agent_message') {
          callbacks.onMessage(data.answer)
        }
        if (data.event === 'message_end') {
          callbacks.onMessageEnd?.({
            totalTokens: data.metadata.usage.total_tokens,
            conversationId: data.conversation_id,
          })
        }
      })
  }
}