feat: exam actions and data safety fixes

src/modules/exams/components/assembly/exam-paper-preview.tsx

@@ -0,0 +1,141 @@
+"use client"
+
+import React from "react"
+import { ScrollArea } from "@/shared/components/ui/scroll-area"
+import { Dialog, DialogContent, DialogHeader, DialogTitle, DialogTrigger } from "@/shared/components/ui/dialog"
+import { Button } from "@/shared/components/ui/button"
+import { Eye, Printer } from "lucide-react"
+import type { ExamNode } from "./selected-question-list"
+
+type ChoiceOption = {
+  id: string
+  text: string
+}
+
+type QuestionContent = {
+  text?: string
+  options?: ChoiceOption[]
+}
+
+type ExamPaperPreviewProps = {
+  title: string
+  subject: string
+  grade: string
+  durationMin: number
+  totalScore: number
+  nodes: ExamNode[]
+}
+
+export function ExamPaperPreview({ title, subject, grade, durationMin, totalScore, nodes }: ExamPaperPreviewProps) {
+  // Helper to flatten questions for continuous numbering
+  let questionCounter = 0
+
+  const renderNode = (node: ExamNode, depth: number = 0) => {
+    if (node.type === 'group') {
+      return (
+        <div key={node.id} className="space-y-4 mb-6">
+          <div className="flex items-center gap-2">
+            <h3 className={`font-bold ${depth === 0 ? 'text-lg' : 'text-md'} text-foreground/90`}>
+              {node.title || "Section"}
+            </h3>
+            {/* Optional: Show section score if needed */}
+          </div>
+          <div className="pl-0">
+            {node.children?.map(child => renderNode(child, depth + 1))}
+          </div>
+        </div>
+      )
+    }
+
+    if (node.type === 'question' && node.question) {
+      questionCounter++
+      const q = node.question
+      const content = q.content as QuestionContent
+      
+      return (
+        <div key={node.id} className="mb-6 break-inside-avoid">
+          <div className="flex gap-2">
+            <span className="font-semibold text-foreground min-w-[24px]">{questionCounter}.</span>
+            <div className="flex-1 space-y-2">
+              <div className="text-foreground/90 leading-relaxed whitespace-pre-wrap">
+                {content.text ?? ""} 
+                <span className="text-muted-foreground text-sm ml-2">({node.score}分)</span>
+              </div>
+              
+              {/* Options for Choice Questions */}
+              {(q.type === 'single_choice' || q.type === 'multiple_choice') && content.options && (
+                <div className="grid grid-cols-1 md:grid-cols-2 gap-y-2 gap-x-4 mt-2 pl-2">
+                  {content.options.map((opt) => (
+                    <div key={opt.id} className="flex gap-2 text-sm text-muted-foreground hover:text-foreground transition-colors">
+                      <span className="font-medium">{opt.id}.</span>
+                      <span>{opt.text}</span>
+                    </div>
+                  ))}
+                </div>
+              )}
+
+              {/* Space for written answers */}
+              {q.type === 'text' && (
+                <div className="mt-4 h-24 border-b border-dashed border-muted-foreground/30 w-full"></div>
+              )}
+            </div>
+          </div>
+        </div>
+      )
+    }
+    return null
+  }
+
+  return (
+    <Dialog>
+      <DialogTrigger asChild>
+        <Button variant="secondary" size="sm" className="gap-2">
+          <Eye className="h-4 w-4" />
+          Preview Exam
+        </Button>
+      </DialogTrigger>
+      <DialogContent className="max-w-4xl h-[90vh] flex flex-col p-0 gap-0">
+        <DialogHeader className="p-6 pb-2 border-b shrink-0">
+          <div className="flex items-center justify-between">
+            <DialogTitle>Exam Preview</DialogTitle>
+            <Button variant="outline" size="sm" onClick={() => window.print()} className="hidden">
+              <Printer className="h-4 w-4 mr-2" />
+              Print
+            </Button>
+          </div>
+        </DialogHeader>
+        
+        <ScrollArea className="flex-1 p-8 bg-white/50 dark:bg-zinc-950/50">
+          <div className="max-w-3xl mx-auto bg-card shadow-sm border p-12 min-h-[1000px] print:shadow-none print:border-none">
+            {/* Header */}
+            <div className="text-center space-y-4 mb-12 border-b-2 border-primary/20 pb-8">
+              <h1 className="text-3xl font-black tracking-tight text-foreground">{title}</h1>
+              <div className="flex justify-center gap-8 text-sm text-muted-foreground font-medium uppercase tracking-wide">
+                <span>Subject: {subject}</span>
+                <span>Grade: {grade}</span>
+                <span>Time: {durationMin} mins</span>
+                <span>Total: {totalScore} pts</span>
+              </div>
+              <div className="flex justify-center gap-12 text-sm pt-4">
+                <div className="w-32 border-b border-foreground/20 text-left px-1">Class:</div>
+                <div className="w-32 border-b border-foreground/20 text-left px-1">Name:</div>
+                <div className="w-32 border-b border-foreground/20 text-left px-1">No.:</div>
+              </div>
+            </div>
+
+            {/* Content */}
+            <div className="space-y-2">
+              {nodes.length === 0 ? (
+                <div className="text-center py-20 text-muted-foreground">
+                  Empty Exam Paper
+                </div>
+              ) : (
+                nodes.map(node => renderNode(node))
+              )}
+            </div>
+          </div>
+        </ScrollArea>
+      </DialogContent>
+    </Dialog>
+  )
+}