feat(提交): 采集编辑过程信号，落进 submission_trace

AI 时代 OJ 设计的第 1 步：给「可信 AC」和学情分析攒数据，本身不判任何事。
- 契约：提交请求加可选的 trace（活跃时长、键入/粘贴/删除字符数、切后台次数等，
  只有计数、不含按键内容）；写成 .optional().catch(undefined)，坏了就当没带，
  不让附带数据把提交挡成 400
- 迁移 0016 建 submission_trace，与 submission 一对一、CASCADE；since_prev_ms
  由服务端在同一条 INSERT 里算（排掉自身），bigint —— 实测已有 44 天的间隔，int4 装不下
- 后端写 trace 失败只记日志，不影响提交
- 前端 oj/problem/utils/editTrace.ts 是模块单例（扩展对象不能过 Pinia 的响应式代理），
  只数带 userEvent 的事务：格式化回写 / 载入草稿 / 协作对方的改动天然排除；
  closeBrackets 越过右括号时是原样替换，按 no-op 跳过。比赛编辑器同样挂上
- 实跑：后端四种请求、前端浏览器里键入/粘贴/删除/setCode 回写/切后台/提交后清零，
  计数与预期逐项一致

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/api/src/db/0016_add_submission_trace.sql

@@ -0,0 +1,18 @@
+-- 提交的编辑过程信号（AI 时代 OJ 设计的第 1 步：过程信号采集），字段含义见 schema.ts 的
+-- submissionTrace 与契约的 submissionTraceSchema。纯建表，历史提交没有对应行，这是预期的。
+CREATE TABLE "submission_trace" (
+	"submission_id" text PRIMARY KEY NOT NULL,
+	"active_ms" integer NOT NULL,
+	"since_open_ms" integer NOT NULL,
+	"typed_chars" integer NOT NULL,
+	"pasted_chars" integer NOT NULL,
+	"paste_count" integer NOT NULL,
+	"max_paste" integer NOT NULL,
+	"deleted_chars" integer NOT NULL,
+	"blur_count" integer NOT NULL,
+	"initial_len" integer NOT NULL,
+	"collab" boolean NOT NULL,
+	"since_prev_ms" bigint
+);
+--> statement-breakpoint
+ALTER TABLE "submission_trace" ADD CONSTRAINT "submission_trace_submission_id_fk_submission_id" FOREIGN KEY ("submission_id") REFERENCES "public"."submission"("id") ON DELETE cascade ON UPDATE no action;

apps/api/src/db/meta/_journal.json

@@ -113,6 +113,13 @@
       "when": 1789364546358,
       "tag": "0015_submission_filter_indexes",
       "breakpoints": true
+    },
+    {
+      "idx": 16,
+      "version": "7",
+      "when": 1789817209482,
+      "tag": "0016_add_submission_trace",
+      "breakpoints": true
     }
   ]
 }

apps/api/src/db/schema.ts

@@ -953,6 +953,44 @@ export const submission = pgTable(
   ],
 )
 
+/**
+ * 提交时附带的编辑过程信号，和 submission 一对一。字段含义见契约的
+ * `submissionTraceSchema`，这里只记表本身的取舍：
+ *
+ * - **没有行 ≠ 可疑。** 2026-09 之前的全部历史提交、刷新过页面的、老版本前端交的
+ *   都没有 trace，用它的地方一律把「缺失」当「无数据」。
+ * - 类型化的列而不是一个 jsonb：「可信 AC」和学情热力图要在 SQL 里按这些值筛、聚合。
+ * - `since_prev_ms` 是唯一由**服务端**算的一列（距同一用户同一道题上一次提交），
+ *   客户端伪造不了；这道题的第一次提交为 null。
+ * - CASCADE 挂在 submission 上、不挂 user：它是提交的附属，提交没了它没有意义，
+ *   人是谁顺着 submission 就能查到。同表的 message / problemset_submission 也是这一档。
+ */
+export const submissionTrace = pgTable(
+  "submission_trace",
+  {
+    submissionId: text("submission_id").primaryKey().notNull(),
+    activeMs: integer("active_ms").notNull(),
+    sinceOpenMs: integer("since_open_ms").notNull(),
+    typedChars: integer("typed_chars").notNull(),
+    pastedChars: integer("pasted_chars").notNull(),
+    pasteCount: integer("paste_count").notNull(),
+    maxPaste: integer("max_paste").notNull(),
+    deletedChars: integer("deleted_chars").notNull(),
+    blurCount: integer("blur_count").notNull(),
+    initialLen: integer("initial_len").notNull(),
+    collab: boolean().notNull(),
+    // bigint：int4 的毫秒数只够 24.8 天，隔一个假期回来重交就溢出了
+    sincePrevMs: bigint("since_prev_ms", { mode: "number" }),
+  },
+  (table) => [
+    foreignKey({
+      columns: [table.submissionId],
+      foreignColumns: [submission.id],
+      name: "submission_trace_submission_id_fk_submission_id",
+    }).onDelete("cascade"),
+  ],
+)
+
 export const tutorial = pgTable(
   "tutorial",
   {

apps/api/src/routes/submission.ts

@@ -8,6 +8,7 @@ import {
   type SubmissionDetail,
   type SubmissionList,
   type SubmissionListItem,
+  type SubmissionTrace,
 } from "@oj2/contract"
 import {
   and,
@@ -59,6 +60,38 @@ function objectValue(value: unknown): Record<string, unknown> {
     : {}
 }
 
+/**
+ * 落编辑过程信号。**失败只记日志、不影响提交** —— 这是附带的统计数据，
+ * 提交已经进库了，不能因为它回一个 500 让学生以为没交上。
+ *
+ * `since_prev_ms` 在同一条 INSERT 里用子查询算，排掉刚插进去的这条自己；
+ * 两次提交并发到达时也各自取到的是对方之外的最近一条。这道题第一次提交时
+ * `max()` 为 null，列就是 null。
+ */
+async function saveTrace(
+  submissionId: string,
+  userId: number,
+  problemId: number,
+  createTime: string,
+  trace: SubmissionTrace,
+) {
+  try {
+    await db.insert(schema.submissionTrace).values({
+      submissionId,
+      ...trace,
+      sincePrevMs: sql`(
+        select (extract(epoch from ${createTime}::timestamptz - max(${schema.submission.createTime})) * 1000)::bigint
+        from ${schema.submission}
+        where ${schema.submission.userId} = ${userId}
+          and ${schema.submission.problemId} = ${problemId}
+          and ${schema.submission.id} <> ${submissionId}
+      )`,
+    })
+  } catch (error) {
+    console.error("Failed to record submission trace", error)
+  }
+}
+
 submissionRoutes.post("/submissions", requireAuth, async (c) => {
   const parsed = createSubmissionRequestSchema.safeParse(
     await c.req.json().catch(() => null),
@@ -168,6 +201,15 @@ submissionRoutes.post("/submissions", requireAuth, async (c) => {
     contestId,
   })
 
+  if (parsed.data.trace)
+    await saveTrace(
+      submissionId,
+      user.id,
+      problem.id,
+      createTime,
+      parsed.data.trace,
+    )
+
   try {
     await judgeQueue.add(
       "judge",

apps/web/src/oj/problem/components/ContestEditor.vue

@@ -7,6 +7,7 @@ import CodeEditor from "shared/components/CodeEditor.vue"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import storage from "utils/storage"
 import type { LANGUAGE } from "utils/types"
+import { beginEditTrace, editTraceExtensions } from "oj/problem/utils/editTrace"
 import Form from "./Form.vue"
 
 const route = useRoute()
@@ -34,6 +35,10 @@ onMounted(() => {
       problem.value!.template[codeStore.code.language] ||
       SOURCES[codeStore.code.language],
   )
+  beginEditTrace(
+    `problem_${problem.value!._id}_contest_${contestID}`,
+    codeStore.code.value.length,
+  )
 })
 
 const changeCode = (v: string) => {
@@ -58,6 +63,7 @@ const changeLanguage = (v: LANGUAGE) => {
       v-model:value="codeStore.code.value"
       :language="codeStore.code.language"
       :height="editorHeight"
+      :extra-extensions="editTraceExtensions"
       @update:model-value="changeCode"
     />
   </n-flex>

apps/web/src/oj/problem/components/ProblemEditor.vue

@@ -8,6 +8,7 @@ import SyncCodeEditor from "shared/components/SyncCodeEditor.vue"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import storage from "utils/storage"
 import type { LANGUAGE } from "utils/types"
+import { beginEditTrace, editTraceExtensions } from "oj/problem/utils/editTrace"
 import Form from "./Form.vue"
 
 const FlowchartEditor = defineAsyncComponent(
@@ -98,6 +99,11 @@ function loadCode() {
       problem.value!.template[codeStore.code.language] ||
       SOURCES[codeStore.code.language],
   )
+  // 换了题才重新计数，同一道题重复 loadCode（协作结束读回草稿）是接着记
+  beginEditTrace(
+    `problem_${problem.value!._id}_contest_${contestID}`,
+    codeStore.code.value.length,
+  )
 }
 
 onMounted(loadCode)
@@ -151,6 +157,7 @@ provide("flowchartEditorRef", flowchartEditorRef)
       :language="codeStore.code.language"
       :problem-id="problem!._id"
       :height="editorHeight"
+      :extra-extensions="editTraceExtensions"
       @update:model-value="changeCode"
     />
   </n-flex>

apps/web/src/oj/problem/components/SubmitCode.vue

@@ -12,6 +12,8 @@ import SubmissionResult from "./SubmissionResult.vue"
 import { getSubmitButtonState } from "./submitButtonState"
 import { useBreakpoints } from "shared/composables/breakpoints"
 import { useUserStore } from "shared/store/user"
+import { useCollabStore } from "shared/store/collab"
+import { restartEditTrace, snapshotEditTrace } from "oj/problem/utils/editTrace"
 import {
   checkPythonSyntax,
   prefetchPythonSyntaxChecker,
@@ -24,6 +26,7 @@ const ProblemReaction = defineAsyncComponent(
 
 // ==================== 基础状态 ====================
 const userStore = useUserStore()
+const collabStore = useCollabStore()
 const codeStore = useCodeStore()
 const problemStore = useProblemStore()
 const { problem } = storeToRefs(problemStore)
@@ -147,6 +150,11 @@ async function submit() {
     problemId: problem.value!.id,
     language: codeStore.code.language,
     code: codeStore.code.value,
+    // 编辑过程信号，见 utils/editTrace.ts。协作的判断和 ProblemEditor 的 collabHere 同一个口径
+    trace: snapshotEditTrace(
+      collabStore.room !== null &&
+        collabStore.room.problemId === problem.value!._id,
+    ),
   }
   if (contestID) {
     data.contestId = parseInt(contestID)
@@ -161,6 +169,8 @@ async function submit() {
   try {
     const res = await submitCode(data)
     console.log(`[Submit] 代码已提交: ID=${res.submissionId}`)
+    // 交上了才清零；被限流 / 网络失败的话这一段接着记，下次提交一起报
+    restartEditTrace(codeStore.code.value.length)
 
     // 3. 启动冷却 + 监控
     startCooldown()

apps/web/src/oj/problem/utils/editTrace.ts

@@ -0,0 +1,139 @@
+import { EditorView } from "@codemirror/view"
+import type { SubmissionTrace } from "@oj2/contract"
+
+/**
+ * 编辑过程信号的采集，随提交一起报给后端（落进 `submission_trace`）。
+ * 字段含义见契约的 `submissionTraceSchema`。**只数字符数和次数，不留任何按键内容。**
+ *
+ * 是模块单例而不是 Pinia store：编辑器（ProblemEditor / ContestEditor 里）和
+ * 提交按钮（Form → SubmitCode）是兄弟组件，得共用一份计数；而 CodeMirror 的
+ * 扩展对象一旦经过 store 就会被包成响应式代理，facet 靠身份比较，代理过的扩展
+ * 直接失效。计数本身也不需要响应式。
+ *
+ * **只数带 userEvent 的事务。** 下面这些都不带，所以天然不会被算进去：
+ * - `codeStore.setCode()` —— vue-codemirror 的 setDoc 只 dispatch 一个 changes：
+ *   提交前的自动格式化、载入草稿 / 模板、切语言都走这条；
+ * - 课堂协作里对方的改动 —— y-codemirror.next 应用远程更新时只挂 ySyncAnnotation。
+ *
+ * 撤销 / 重做、编辑器内部拖动（`move.drop`）也不数：它们既不是新写的也不是外来的。
+ */
+
+/** 两次编辑间隔超过这个就算走开了，中间这段不计入活跃时长 */
+const IDLE_MS = 60_000
+
+let key: string | null = null
+let startedAt = 0
+let lastEditAt: number | null = null
+let activeMs = 0
+let typedChars = 0
+let pastedChars = 0
+let pasteCount = 0
+let maxPaste = 0
+let deletedChars = 0
+let blurCount = 0
+let initialLen = 0
+
+function reset(len: number) {
+  startedAt = performance.now()
+  lastEditAt = null
+  activeMs = 0
+  typedChars = 0
+  pastedChars = 0
+  pasteCount = 0
+  maxPaste = 0
+  deletedChars = 0
+  blurCount = 0
+  initialLen = len
+}
+
+/**
+ * 开始（或接着）记一道题。编辑器载入代码之后调。
+ *
+ * `traceKey` 没变就**什么都不做** —— 同一道题里切去看提交记录、再切回来，
+ * 编辑器可能会重新挂载，不能因此把这一段的计数清掉。换了题才重新开始。
+ * 切语言不换 key：学生改用另一种语言重写这道题，仍然是同一段做题过程。
+ */
+export function beginEditTrace(traceKey: string, len: number) {
+  if (traceKey === key) return
+  key = traceKey
+  reset(len)
+}
+
+/** 这一段的快照，附在提交请求上 */
+export function snapshotEditTrace(collab: boolean): SubmissionTrace {
+  return {
+    activeMs: Math.round(activeMs),
+    sinceOpenMs: Math.round(performance.now() - startedAt),
+    typedChars,
+    pastedChars,
+    pasteCount,
+    maxPaste,
+    deletedChars,
+    blurCount,
+    initialLen,
+    collab,
+  }
+}
+
+/** 提交成功之后调：下一条提交只记从这里往后的那一段 */
+export function restartEditTrace(len: number) {
+  reset(len)
+}
+
+function touch() {
+  const now = performance.now()
+  if (lastEditAt !== null && now - lastEditAt <= IDLE_MS)
+    activeMs += now - lastEditAt
+  lastEditAt = now
+}
+
+// 只数 hidden 这一个事件：切标签页时 window 的 blur 和 visibilitychange 会一起触发，
+// 两个都数就是一次记两下。代价是同屏切到别的窗口（页面仍可见）不计，这本来就只是辅助信号。
+document.addEventListener("visibilitychange", () => {
+  if (document.visibilityState !== "hidden") return
+  blurCount++
+  // 切走的这段不算活跃，回来之后的第一下编辑重新起算
+  lastEditAt = null
+})
+
+/** 挂到题目页的代码编辑器上。同一个实例，别每次渲染新建 —— 那会让编辑器反复重配扩展 */
+export const editTraceExtensions = [
+  EditorView.updateListener.of((update) => {
+    if (!update.docChanged) return
+    for (const tr of update.transactions) {
+      if (!tr.docChanged) continue
+      // 顺序要紧：isUserEvent("input") 也会匹配 "input.paste"
+      const pasted =
+        tr.isUserEvent("input.paste") || tr.isUserEvent("input.drop")
+      const typed = !pasted && tr.isUserEvent("input")
+      const deleted = tr.isUserEvent("delete")
+      if (!pasted && !typed && !deleted) continue
+
+      let inserted = 0
+      let removed = 0
+      tr.changes.iterChanges((fromA, toA, _fromB, _toB, text) => {
+        // 原样替换不算：closeBrackets 越过已有的右括号 / 引号时，是把 `)` 替换成 `)`
+        // 而不是只挪光标（@codemirror/autocomplete 的 handleClose），不排掉的话
+        // 每敲一个右括号就多记一个键入加一个删除
+        if (
+          toA - fromA === text.length &&
+          tr.startState.sliceDoc(fromA, toA) === text.toString()
+        )
+          return
+        removed += toA - fromA
+        inserted += text.length
+      })
+
+      // 选中一段再打字 / 粘贴，被替换掉的那部分也算删除
+      deletedChars += removed
+      if (pasted) {
+        pastedChars += inserted
+        pasteCount++
+        if (inserted > maxPaste) maxPaste = inserted
+      } else if (typed) {
+        typedChars += inserted
+      }
+      touch()
+    }
+  }),
+]

apps/web/src/shared/components/CodeEditor.vue

@@ -4,6 +4,7 @@ import { python } from "@codemirror/lang-python"
 import { sql, SQLite } from "@codemirror/lang-sql"
 import { bracketMatching } from "@codemirror/language"
 import { Codemirror } from "vue-codemirror"
+import type { Extension } from "@codemirror/state"
 import {
   autocompletion,
   closeBrackets,
@@ -21,6 +22,8 @@ interface Props {
   height?: string
   readonly?: boolean
   placeholder?: string
+  /** 追加的 CodeMirror 扩展。传一个稳定的数组实例，每次渲染新建会让编辑器反复重配 */
+  extraExtensions?: Extension[]
 }
 
 const {
@@ -29,6 +32,7 @@ const {
   height = "100%",
   readonly = false,
   placeholder = "",
+  extraExtensions = [],
 } = defineProps<Props>()
 const code = defineModel<string>("value")
 
@@ -49,6 +53,7 @@ const extensions = computed(() => [
     override: [enhanceCompletion(language), completeAnyWord],
   }),
   isDark.value ? oneDark : smoothy,
+  ...extraExtensions,
 ])
 </script>
 

apps/web/src/shared/components/SyncCodeEditor.vue

@@ -7,6 +7,7 @@ import {
   completeAnyWord,
 } from "@codemirror/autocomplete"
 import type { EditorView } from "@codemirror/view"
+import type { Extension } from "@codemirror/state"
 import type { LANGUAGE } from "utils/types"
 import { oneDark } from "../themes/oneDark"
 import { smoothy } from "../themes/smoothy"
@@ -26,6 +27,8 @@ interface Props {
   height?: string
   readonly?: boolean
   placeholder?: string
+  /** 追加的 CodeMirror 扩展。传一个稳定的数组实例，每次渲染新建会让编辑器反复重配 */
+  extraExtensions?: Extension[]
   /**
    * 当前这个编辑器属于哪道题（题目的展示 ID）。
    *
@@ -43,6 +46,7 @@ const {
   height = "100%",
   readonly = false,
   placeholder = "",
+  extraExtensions = [],
   problemId = "",
 } = defineProps<Props>()
 const code = defineModel<string>("value")
@@ -59,6 +63,7 @@ const extensions = computed(() => [
     override: [enhanceCompletion(language), completeAnyWord],
   }),
   getInitialExtension(),
+  ...extraExtensions,
 ])
 
 interface EditorReadyPayload {