OJ2/apps/web/src/shared/components/FlowchartEditor/index.vue

<script lang="ts" setup>
import { ref, onMounted, onUnmounted } from "vue"
import Toolbar from "./Toolbar.vue"
import "@vue-flow/core/dist/style.css"
import "@vue-flow/core/dist/theme-default.css"
import "@vue-flow/controls/dist/style.css"
import { useVueFlow, VueFlow, type Node, type Edge, MarkerType } from "@vue-flow/core"
import { Controls } from "@vue-flow/controls"
import { Background } from "@vue-flow/background"

import { useDnD, currentDragNodeType } from "./useDnD"
import { getNodeTypeConfig } from "./useNodeStyles"
import { useHistory } from "./useHistory"
import { useFlowOperations } from "./useFlowOperations"
import { useCache } from "./useCache"
import { toPortableEdges, toPortableNodes } from "./serialize"
import CustomNode from "./CustomNode.vue"
import { useProblemStore } from "oj/store/problem"

interface Props {
  height?: string
}

const { height = "calc(100vh - 133px)" } = defineProps<Props>()

// Vue Flow 实例
const { addEdges, removeNodes, removeEdges, fitView, onNodesInitialized } = useVueFlow()

/**
 * 进页面读回草稿、载回旧版之后缩放到正好装下整张图。原来画布停在默认的位置和缩放上，
 * 图大一点就有一半在外面，学生以为草稿丢了。只在这两种时候缩：拖进一个新节点时也会
 * 触发 nodes-initialized，那时候跟着缩放会让画布跳一下。
 * 画布是空的就不挂：空画布不会触发 nodes-initialized，挂着的这一下会一直留到学生拖进
 * 第一个节点，正好把画布拉近、对准那一个节点 —— 就是上面要躲开的那一跳
 */
let fitPending = false
function fitSoon() {
  fitPending = nodes.value.length > 0
}
onNodesInitialized(() => {
  if (!fitPending) return
  fitPending = false
  fitView({ padding: 0.15, maxZoom: 1.2 })
})

// 节点和边的响应式数据
// 显式标注成 Ref<Node[]>，不走 ref<T>() 的 UnwrapRef 推导 —— vue-flow 的
// Node/Edge 嵌套很深，让 TS 去调和两种形态会直接撞上「实例化层级过深」
const nodes = ref([]) as Ref<Node[]>
const edges = ref([]) as Ref<Edge[]>

// 历史记录管理
const { canUndo, canRedo, resetHistory, saveState, undo, redo } = useHistory()

const problemStore = useProblemStore()
const { problem } = storeToRefs(problemStore)
const route = useRoute()
/**
 * 缓存管理：用 computed key 支持题目 ID 异步加载后自动切换到正确的 storage。
 * 题单入口单独一份草稿：加入题单之前在题库里画到 A 的那张，不能一进题单就摆在画布上
 * （设计文档第 11 节 3，和代码草稿同理）
 */
const cacheKey = computed(() => {
  if (!problem.value?._id) return "flowchart-editor-data"
  const base = `flowchart-editor-data-problem-${problem.value._id}`
  const problemSetId = route.params.problemSetId
  return problemSetId ? `${base}-problemset-${problemSetId}` : base
})
const { isSaving, lastSaved, hasUnsavedChanges, saveToCache, loadFromCache, clearCache } = useCache(
  nodes,
  edges,
  cacheKey,
  () => {
    // 换题后画布已经被换成新题的草稿，历史必须跟着重建，
    // 否则一次撤销就会把上一题的图还原到这一题里
    resetHistory(nodes.value, edges.value)
    fitSoon()
  },
)

// 拖拽处理
const { onDragOver, onDragLeave, onDrop, isDragOver, screenDragPos } = useDnD()

const dragPreviewStyle = computed(() => {
  if (!screenDragPos.value || !currentDragNodeType.value) return null
  const config = getNodeTypeConfig(currentDragNodeType.value)
  const type = currentDragNodeType.value
  return {
    left: `${screenDragPos.value.x}px`,
    top: `${screenDragPos.value.y}px`,
    background: config.color,
    borderRadius: type === "start" || type === "end" ? "20px" : "8px",
  }
})

// 流程操作
const {
  handleConnect,
  handleEdgeClick,
  handleNodeDelete,
  handleNodeUpdate,
  clearCanvas,
  deleteSelected,
} = useFlowOperations(nodes, edges, addEdges, removeNodes, removeEdges, saveState)

const handleDrop = async (event: DragEvent) => {
  const newNode = onDrop(event)
  if (newNode) {
    await nextTick()
    saveState(nodes.value, edges.value)
  }
}

// 撤销/重做处理
const handleUndo = () => {
  const state = undo()
  if (state) {
    nodes.value = state.nodes
    edges.value = state.edges
    saveToCache()
  }
}

const handleRedo = () => {
  const state = redo()
  if (state) {
    nodes.value = state.nodes
    edges.value = state.edges
    saveToCache()
  }
}

// 清空画布。工具栏那个按钮点一下就全没了，且 clearCache() 会连本题存着的草稿
// 一起删掉，刷新也找不回来 —— 学生误点的代价太大，加一道确认
const dialog = useDialog()
const handleClear = () => {
  if (nodes.value.length === 0 && edges.value.length === 0) return
  dialog.warning({
    title: "清空画布",
    content: "画布上的内容会被清掉，这道题存着的草稿也会一起删除。确定吗？",
    positiveText: "清空",
    negativeText: "再想想",
    onPositiveClick: () => {
      clearCanvas()
      clearCache()
    },
  })
}

// 键盘事件
const handleKeyDown = (event: KeyboardEvent) => {
  if (event.target instanceof HTMLInputElement || event.target instanceof HTMLTextAreaElement)
    return

  if (event.key === "Delete" || event.key === "Backspace") {
    deleteSelected()
  }

  if (event.ctrlKey || event.metaKey) {
    const key = event.key.toLowerCase()
    if (key === "z" && !event.shiftKey) {
      event.preventDefault()
      handleUndo()
    } else if ((key === "z" && event.shiftKey) || key === "y") {
      // 工具栏上的提示写的就是 Ctrl+Y，但原来只实现了 Ctrl+Shift+Z，按 Y 没反应
      event.preventDefault()
      handleRedo()
    }
  }
}

onMounted(() => {
  document.addEventListener("keydown", handleKeyDown)

  // 从缓存恢复数据，并把当前画布作为历史起点，
  // 否则第一步操作没有可回退的目标，撤销按钮一直是灰的
  loadFromCache()
  resetHistory(nodes.value, edges.value)
  fitSoon()
})

onUnmounted(() => {
  document.removeEventListener("keydown", handleKeyDown)
})

// 加载外部数据到编辑器
const setFlowchartData = (data: { nodes: Node[]; edges: Edge[] }) => {
  if (data && data.nodes && data.edges) {
    // 确保节点数据包含必要的位置信息
    const processedNodes = data.nodes.map((node) => ({
      ...node,
      position: node.position || { x: 0, y: 0 },
    }))

    // 确保边数据包含必要的 handle 信息
    const processedEdges = data.edges.map((edge) => ({
      ...edge,
      sourceHandle: edge.sourceHandle || null,
      targetHandle: edge.targetHandle || null,
    }))

    nodes.value = processedNodes
    edges.value = processedEdges
    saveState(nodes.value, edges.value)
    fitSoon()
  }
}

// 暴露节点和边数据给父组件
defineExpose({
  nodes,
  edges,
  // 提交出去的这份会压缩后长期存进数据库，同样裁掉运行时内部字段
  getFlowchartData: () => ({
    nodes: toPortableNodes(nodes.value),
    edges: toPortableEdges(edges.value),
  }),
  setFlowchartData,
})
</script>

<template>
  <div class="container" :style="{ height }">
    <!-- 拖拽时跟随鼠标的节点预览 -->
    <Transition name="drag-preview">
      <div
        v-if="isDragOver && dragPreviewStyle && currentDragNodeType"
        class="drag-node-preview"
        :style="dragPreviewStyle"
      >
        <span class="preview-icon">{{ getNodeTypeConfig(currentDragNodeType).icon }}</span>
        <span>{{ getNodeTypeConfig(currentDragNodeType).label }}</span>
      </div>
    </Transition>
    <VueFlow
      v-model:nodes="nodes"
      v-model:edges="edges"
      @dragover="onDragOver"
      @dragleave="onDragLeave"
      @drop="handleDrop"
      @connect="handleConnect"
      @edge-click="handleEdgeClick"
      :default-edge-options="{
        type: 'default',
        style: {
          stroke: '#6366f1',
          strokeWidth: 2.5,
          cursor: 'pointer',
          filter: 'drop-shadow(0 2px 4px rgba(0,0,0,0.1))',
        },
        markerEnd: {
          type: MarkerType.ArrowClosed,
          color: '#6366f1',
          width: 16,
          height: 16,
        },
      }"
      :connection-line-style="{
        stroke: '#6366f1',
        strokeWidth: 2.5,
        strokeDasharray: '8,4',
        markerEnd: 'url(#connection-arrow)',
        filter: 'drop-shadow(0 2px 4px rgba(0,0,0,0.1))',
      }"
      :fit-view-on-init="false"
      :connect-on-click="false"
      :multi-selection-key-code="null"
      :delete-key-code="null"
    >
      <!-- SVG 定义用于连接线箭头 -->
      <defs>
        <marker
          id="connection-arrow"
          markerWidth="12"
          markerHeight="12"
          refX="10"
          refY="3"
          orient="auto"
          markerUnits="strokeWidth"
        >
          <path d="M0,0 L0,6 L10,3 z" fill="#6366f1" stroke="#6366f1" strokeWidth="0.5" />
        </marker>
      </defs>
      <template #node-custom="{ data, id, type }">
        <CustomNode
          :id="id"
          :type="type"
          :data="data"
          @delete="handleNodeDelete"
          @update="handleNodeUpdate"
        />
      </template>

      <Background variant="lines" :gap="20" :size="1" />
      <Controls />
      <Toolbar
        :can-undo="canUndo"
        :can-redo="canRedo"
        :is-saving="isSaving"
        :last-saved="lastSaved"
        :has-unsaved-changes="hasUnsavedChanges"
        @clear="handleClear"
        @undo="handleUndo"
        @redo="handleRedo"
        @deleteNode="handleNodeDelete"
      />
    </VueFlow>
  </div>
</template>

<style scoped>
.container {
  width: 100%;
  height: 100%;
  position: relative;
}

.drag-node-preview {
  position: fixed;
  transform: translate(-50%, -50%);
  pointer-events: none;
  z-index: 9999;
  padding: 8px 18px;
  color: white;
  font-size: 14px;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 8px;
  opacity: 0.55;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
  white-space: nowrap;
  border: 2px dashed rgba(255, 255, 255, 0.6);
  user-select: none;
}

.preview-icon {
  font-size: 16px;
}

.drag-preview-enter-active,
.drag-preview-leave-active {
  transition: opacity 0.1s ease;
}
.drag-preview-enter-from,
.drag-preview-leave-to {
  opacity: 0;
}
</style>