feat(signing): 统一演示文书库并支持下载签名原图

clinical-web/src/api/workbench/artifacts.ts

@@ -4,6 +4,7 @@ import { unwrapApiResponse } from '@/utils/api-response'
 import { mockFlags } from '@/utils/mock-flags'
 import { request } from '@/utils/request'
 
+import { getMockSigningTask } from './signing'
 import type {
   ApiPageResponse,
   ApiResponseOf,
@@ -70,9 +71,71 @@ function normalizeArtifact(dto: SignArtifactResponseDto): SigningArtifact {
 
 export const isArtifactMockEnabled = useMockData
 
+/**
+ * 演示签名原图产物的 id 前缀。
+ * 演示环境没有文件服务，下载时靠 id 反查任务里的签名图，
+ * 保证「签名原图」在演示里也是真能下载到的文件，而不是占位提示。
+ */
+const MOCK_SIGNATURE_PREFIX = 'mock-signature-'
+
+function estimateDataUrlBytes(dataUrl: string) {
+  const payload = dataUrl.split(',')[1]
+
+  if (!payload) {
+    return 0
+  }
+
+  // base64 每 4 个字符还原 3 字节，末尾可能有填充，这里取近似值用于展示
+  return Math.floor((payload.replace(/=+$/, '').length * 3) / 4)
+}
+
+/** 演示产物：已签署且有签名图时，给出可下载的签名原图 */
+function buildMockArtifacts(taskId: string): SigningArtifact[] {
+  const task = getMockSigningTask(taskId)
+
+  if (!task || task.status !== 'signed' || !task.signatureDataUrl) {
+    return []
+  }
+
+  return [
+    {
+      id: `${MOCK_SIGNATURE_PREFIX}${task.id}`,
+      taskId: task.id,
+      pipelineId: `mock-pipeline-${task.id}`,
+      artifactType: 'SIGNATURE_IMAGE',
+      label: artifactLabels.SIGNATURE_IMAGE ?? '签名原图',
+      fileName: '签名原图.png',
+      mimeType: 'image/png',
+      sizeBytes: estimateDataUrlBytes(task.signatureDataUrl),
+      sha256: '',
+      metadata: {},
+      createdAt: formatDateTime(task.signedAt ?? task.updatedAt),
+    },
+  ]
+}
+
+/** 把签名图 dataURL 还原成可下载的二进制 Blob */
+function dataUrlToBlob(dataUrl: string): Blob {
+  const [meta, payload] = dataUrl.split(',')
+  const mimeType = /data:([^;]+)/.exec(meta ?? '')?.[1] ?? 'application/octet-stream'
+
+  if (!payload) {
+    return new Blob([], { type: mimeType })
+  }
+
+  const binary = window.atob(payload)
+  const bytes = new Uint8Array(binary.length)
+
+  for (let index = 0; index < binary.length; index += 1) {
+    bytes[index] = binary.charCodeAt(index)
+  }
+
+  return new Blob([bytes], { type: mimeType })
+}
+
 export async function getSigningArtifacts(taskId: string): Promise<SigningArtifact[]> {
   if (useMockData) {
-    return []
+    return buildMockArtifacts(taskId)
   }
 
   try {
@@ -115,6 +178,16 @@ export async function getSigningArtifact(
 
 export function downloadSigningArtifact(artifactId: string): Promise<Blob> {
   if (useMockData) {
+    // 演示环境没有文件服务，按 id 反查任务里的签名图，返回真实的 PNG
+    if (artifactId.startsWith(MOCK_SIGNATURE_PREFIX)) {
+      const taskId = artifactId.slice(MOCK_SIGNATURE_PREFIX.length)
+      const signatureDataUrl = getMockSigningTask(taskId)?.signatureDataUrl
+
+      if (signatureDataUrl) {
+        return Promise.resolve(dataUrlToBlob(signatureDataUrl))
+      }
+    }
+
     return Promise.resolve(new Blob(['Mock 签署文件，仅用于界面演示。'], { type: 'text/plain' }))
   }