feat(后台): 编程题出题页重做——左边写，右边是学生看到的样子；例子和测试数据的输出都由标准答案跑出来，改老题能直接看、改测试数据

- 例子就是测试数据里勾了「当例子」的几组，不再手抄输出；老题的例子不在测试数据里的补到最后
- 改了答案，输出变了的那组标黄、写清原来存的是什么；答案在某组上报错就挡住保存
- 没存标准答案的老题输出手写；太大的测试数据（>100 组或单文件 >32KB）只能导入 / 下载 zip
- 预制代码只写学生看得到的那段，前后藏起来的代码收进折叠；语法要求先拿标准答案自测
- 流程图两个互斥开关改成三选一；时间 / 内存限制能改了；草稿只给新建页
- 后端：读回测试点原文、语法要求自测、AI 想测试输入三个接口

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/src/routes/admin/problem.ts

@@ -1,6 +1,10 @@
 import {
   addContestProblemRequestSchema,
+  astCheckRequestSchema,
+  generateTestInputsRequestSchema,
   isSqlProblem,
+  TEST_CASE_EDIT_MAX_CASES,
+  TEST_CASE_EDIT_MAX_FILE_BYTES,
   createProblemRequestSchema,
   generateSqlTestCaseRequestSchema,
   makeProblemPublicRequestSchema,
@@ -9,11 +13,14 @@ import {
   type AdminProblem,
   type AdminProblemList,
   type AdminProblemListItem,
+  type AstCheckResponse,
   type AstRules,
+  type GenerateTestInputsResponse,
   type GenerateSqlTestCaseResponse,
   type SqlConfig,
   type SqlDisplay,
   type SqlTestCaseScript,
+  type TestCaseFiles,
   type UploadTestCaseResponse,
 } from "@oj2/contract"
 import { and, count, desc, eq, ilike, inArray, isNull, ne, not, or, sql } from "drizzle-orm"
@@ -23,15 +30,17 @@ import { requireProblemPermission, type AppEnv } from "../../auth/middleware"
 import type { AuthUser } from "../../auth/session"
 import { db, schema, type DbOrTx } from "../../db"
 import { failure, parseBody, success } from "../../http"
-import { astRulesError, pickAstRules } from "../../judge/ast"
+import { astRulesError, checkAst, describeAstRule, pickAstRules } from "../../judge/ast"
 import { buildSqlDisplay } from "../../judge/sql"
 import { completeChat } from "../../services/ai"
+import { plainText } from "../../services/hint-diagnosis"
 import { contestStatus } from "../../services/contest"
 import {
   packTestCaseZip,
   processTestCaseZip,
   readInfo,
   readSqlScripts,
+  readTestCaseFiles,
   TestCaseError,
 } from "../../services/test-case"
 import { config } from "../../config"
@@ -863,6 +872,95 @@ adminProblemRoutes.get("/problems/:id/sql-scripts", requireProblemPermission, as
   }
 })
 
+/**
+ * 回显编程题已有的测试点原文，出题页就地改。太大的（见契约 TEST_CASE_EDIT_*）只给数量和大小。
+ * SQL 题的测试点是脚本，走上面的 sql-scripts。
+ */
+adminProblemRoutes.get("/problems/:id/test-case-files", requireProblemPermission, async (c) => {
+  const [problem] = await db
+    .select()
+    .from(schema.problem)
+    .where(eq(schema.problem.id, queryInteger(c.req.param("id"), 0, { min: 1 })))
+    .limit(1)
+  if (!problem) return failure(c, 404, "problem-not-found", "Problem does not exist")
+  if (!(await canEdit(c.get("user")!, problem))) {
+    return failure(c, 404, "problem-not-found", "Problem does not exist")
+  }
+  const info = await readInfo(problem.testCaseId)
+  if (info?.sql) return failure(c, 409, "sql-test-case", "该题的测试点是 SQL 脚本")
+  try {
+    const files = await readTestCaseFiles(problem.testCaseId, {
+      maxCases: TEST_CASE_EDIT_MAX_CASES,
+      maxFileBytes: TEST_CASE_EDIT_MAX_FILE_BYTES,
+    })
+    return success(c, files satisfies TestCaseFiles)
+  } catch (error) {
+    if (error instanceof TestCaseError)
+      return failure(c, 404, "test-case-not-found", "测试点文件不存在")
+    throw error
+  }
+})
+
+/** 语法要求：每条规则学生看到的那句话 + 标准答案过不过，和判题时同一个 checkAst */
+adminProblemRoutes.post("/ast-check", requireProblemPermission, async (c) => {
+  const parsed = await parseBody(c, astCheckRequestSchema)
+  if (!parsed.success) return parsed.response
+  const { language, code, rules } = parsed.data
+  const error = astRulesError({ [language]: rules })
+  if (error) return failure(c, 400, "invalid-ast-rules", error)
+  const checked = []
+  for (const rule of rules) {
+    const description = describeAstRule(rule, language)
+    if (!code.trim()) {
+      checked.push({ description, passed: null })
+      continue
+    }
+    const [result] = (await checkAst(code, language, [rule])).results
+    checked.push({ description, passed: result?.passed ?? null, actual: result?.actual })
+  }
+  return success(c, { rules: checked } satisfies AstCheckResponse)
+})
+
+/**
+ * AI 按题面和标准答案想几组测试输入。只要输入：输出一律由标准答案在判题机上跑，
+ * AI 编的输出不可信。
+ */
+adminProblemRoutes.post("/test-inputs/generate", requireProblemPermission, async (c) => {
+  const parsed = await parseBody(c, generateTestInputsRequestSchema)
+  if (!parsed.success) return parsed.response
+  const body = parsed.data
+  const existing = body.existing.length
+    ? body.existing.map((input, i) => `第 ${i + 1} 组：\n${input}`).join("\n\n")
+    : "（还没有）"
+  try {
+    const raw = await completeChat(
+      `你是编程题出题助手，帮老师补测试数据。老师会给你题目描述、输入说明、标准答案和已有的测试输入。
+请再想 5 组新的测试输入，要和已有的不重复，重点覆盖边界情况（最小值、最大值、0、负数、
+重复元素、只有一个元素、各个分支都要走到……），但必须严格符合输入说明的格式，标准答案要能正常处理。
+数据规模保持小，每组不超过 20 行。
+只回 json：{"inputs": ["第一组输入", "第二组输入", ...]}，每组输入是一个字符串，多行用 \\n 分隔。`,
+      [
+        `题目描述：${plainText(body.description).slice(0, 3000)}`,
+        `输入说明：${plainText(body.inputDescription).slice(0, 1000) || "无"}`,
+        `标准答案（${body.language}）：\n${body.answer}`,
+        `已有的测试输入：\n${existing.slice(0, 4000)}`,
+      ].join("\n\n"),
+      { json: true },
+    )
+    const value: unknown = JSON.parse(raw)
+    const list =
+      value && typeof value === "object" && Array.isArray((value as { inputs?: unknown }).inputs)
+        ? ((value as { inputs: unknown[] }).inputs.filter((x) => typeof x === "string") as string[])
+        : []
+    const known = new Set(body.existing.map((input) => input.trim()))
+    const inputs = list.filter((input) => !known.has(input.trim())).slice(0, 10)
+    return success(c, { inputs } satisfies GenerateTestInputsResponse)
+  } catch (error) {
+    console.error("Test input generation failed", error)
+    return failure(c, 502, "ai-unavailable", "生成失败，请稍后再试")
+  }
+})
+
 /** SQL 题测试点预览：跑一遍初始化脚本 + 标准答案，返回题目页要展示的数据表与期望结果 */
 adminProblemRoutes.post("/sql-test-cases/preview", requireProblemPermission, async (c) => {
   const parsed = await parseBody(c, sqlPreviewRequestSchema)

apps/api/src/services/hint-diagnosis.ts

@@ -88,7 +88,7 @@ function errInfo(row: HintRow) {
  * 输出说明里的 `<`、` ` 恰恰可能就是格式要求本身，不解码模型会读歪。
  * 图片直接丢掉（模型看不到图），只留一个占位，让它知道那里原本有东西。
  */
-function plainText(html: string) {
+export function plainText(html: string) {
   return (
     html
       .replace(/<img\b[^>]*>/gi, "[图片]")

apps/api/src/services/test-case.ts

@@ -1,5 +1,5 @@
 import { createHash } from "node:crypto"
-import { mkdir, chmod, readdir, readFile, writeFile } from "node:fs/promises"
+import { mkdir, chmod, readdir, readFile, stat, writeFile } from "node:fs/promises"
 import { resolve } from "node:path"
 
 import { unzipSync, zipSync } from "fflate"
@@ -250,6 +250,43 @@ export async function readSqlScripts(testCaseId: string) {
   return scripts
 }
 
+/**
+ * 读回编程题测试点的原文（出题页回显、就地改）。超过 `limits` 的只报数量和大小，不读内容。
+ * 目录不存在时抛 TestCaseError。
+ */
+export async function readTestCaseFiles(
+  testCaseId: string,
+  limits: { maxCases: number; maxFileBytes: number },
+): Promise<
+  | { editable: true; cases: { input: string; output: string }[] }
+  | { editable: false; count: number; totalBytes: number }
+> {
+  const directory = resolve(config.testCaseDirectory, testCaseId)
+  let entries: string[]
+  try {
+    entries = await readdir(directory)
+  } catch {
+    throw new TestCaseError("Test case does not exist")
+  }
+  const pairs = collectPairs(new Set(entries))
+  let totalBytes = 0
+  let tooLarge = pairs.length > limits.maxCases
+  for (const name of pairs.flat()) {
+    const size = (await stat(resolve(directory, name))).size
+    totalBytes += size
+    if (size > limits.maxFileBytes) tooLarge = true
+  }
+  if (tooLarge) return { editable: false, count: pairs.length, totalBytes }
+  const cases: { input: string; output: string }[] = []
+  for (const [input, output] of pairs) {
+    cases.push({
+      input: await readFile(resolve(directory, input), "utf8"),
+      output: await readFile(resolve(directory, output), "utf8"),
+    })
+  }
+  return { editable: true, cases }
+}
+
 function randomId() {
   const alphabet = "abcdefghijklmnopqrstuvwxyz0123456789"
   const bytes = new Uint8Array(32)