dify/web/app/components/workflow-app/hooks/use-workflow-draft-graph-for-canvas.ts

import type {
  Node,
  WorkflowDataUpdater,
} from '@/app/components/workflow/types'
import { useCallback } from 'react'
import { useTranslation } from 'react-i18next'
import { START_INITIAL_POSITION } from '@/app/components/workflow/constants'
import startPlaceholderDefault from '@/app/components/workflow/nodes/start-placeholder/default'
import { BlockEnum } from '@/app/components/workflow/types'
import { generateNewNode } from '@/app/components/workflow/utils'
import { AppModeEnum } from '@/types/app'

type HydrateWorkflowDraftGraphOptions = {
  localStartPlaceholderNodes?: Node[]
}

const hasWorkflowEntryNode = (nodes: Node[] = []): boolean => {
  return nodes.some(node => (
    node?.data?.type === BlockEnum.Start
    || node?.data?.type === BlockEnum.TriggerSchedule
    || node?.data?.type === BlockEnum.TriggerWebhook
    || node?.data?.type === BlockEnum.TriggerPlugin
  ))
}

const hasStartPlaceholderNode = (nodes: Node[] = []): boolean => {
  return nodes.some(node => node?.data?.type === BlockEnum.StartPlaceholder)
}

export const useWorkflowDraftGraphForCanvas = (appMode?: AppModeEnum | string) => {
  const { t } = useTranslation()

  const getNodesWithLocalStartPlaceholder = useCallback((
    nodes: Node[] = [],
    localStartPlaceholderNodes?: Node[],
  ) => {
    if (appMode !== AppModeEnum.WORKFLOW || hasWorkflowEntryNode(nodes) || hasStartPlaceholderNode(nodes))
      return nodes

    if (localStartPlaceholderNodes?.length)
      return [...localStartPlaceholderNodes, ...nodes]

    const { newNode: startPlaceholderNode } = generateNewNode({
      data: {
        ...startPlaceholderDefault.defaultValue,
        selected: true,
        type: startPlaceholderDefault.metaData.type,
        title: t(`blocks.${startPlaceholderDefault.metaData.type}`, { ns: 'workflow' }),
        desc: '',
      },
      position: START_INITIAL_POSITION,
    })

    return [startPlaceholderNode, ...nodes]
  }, [appMode, t])

  const getWorkflowDraftGraphForCanvas = useCallback((
    graph?: Partial<WorkflowDataUpdater>,
    options?: HydrateWorkflowDraftGraphOptions,
  ): WorkflowDataUpdater => {
    const nodes = getNodesWithLocalStartPlaceholder(
      graph?.nodes || [],
      options?.localStartPlaceholderNodes,
    )

    return {
      nodes,
      edges: graph?.edges || [],
      viewport: graph?.viewport || { x: 0, y: 0, zoom: 1 },
    }
  }, [getNodesWithLocalStartPlaceholder])

  return {
    getWorkflowDraftGraphForCanvas,
  }
}