import { randomBytes } from "node:crypto"

import {
  createSubmissionRequestSchema,
  formatCodeRequestSchema,
  type CreateSubmissionResponse,
  type FormatCodeResponse,
  type SubmissionDetail,
  type SubmissionList,
  type SubmissionListItem,
  type SubmissionTrace,
} from "@oj2/contract"
import { and, count, desc, eq, inArray, isNull, sql, type SQL } from "drizzle-orm"
import { Hono } from "hono"

import { optionalAuth, requireAuth, requireTeacher } from "../auth/middleware"
import type { AuthUser } from "../auth/session"
import { db, schema } from "../db"
import { failure, parseBody, success } from "../http"
import { compileFails, templateForLanguage } from "../judge/run"
import { JudgeStatus } from "../judge/status"
import { parseProblemTemplate } from "../judge/template"
import { judgeQueue } from "../queue"
import {
  canAccessContest,
  contestStatus,
  findAccessibleContest,
  requireContestAccess,
  type ContestEnv,
} from "../services/contest"
import { CodeFormatError, formatCode } from "../services/format-code"
import { getBooleanOption } from "../services/options"
import { problemSetLockCutoffs } from "../services/problemset"
import { consumeToken } from "../services/throttling"
import { dayStart } from "../time"
import { asFilterValue, asRecord, isAdminRole, isTeacherOrAbove, queryInteger } from "./helpers"
import {
  classNameFilter,
  exactUsernameFilter,
  problemFilter,
  submissionStatisticsRoutes,
  unknownDisplayIds,
  usernameFilter,
} from "./submission-statistics"

export const submissionRoutes = new Hono<ContestEnv>()

/**
 * 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 = await parseBody(c, createSubmissionRequestSchema, "Invalid submission payload")
  if (!parsed.success) return parsed.response
  let contestId: number | null = null
  if (parsed.data.contestId) {
    // 这里用不了 requireContestAccess 中间件：比赛 id 来自请求体，
    // 中间件跑的时候 body 还没解析。全仓只有这一处仍是手工调用，改动时留意别漏掉鉴权。
    const contest = await findAccessibleContest(c.get("user"), parsed.data.contestId)
    if (!contest) return failure(c, 404, "contest-not-found", "Contest does not exist")
    const access = await canAccessContest(c, contest, "problems")
    if (!access.ok)
      return failure(c, access.code === "login-required" ? 401 : 403, access.code, access.message)
    if (contestStatus(contest) === "-1")
      return failure(c, 403, "contest-ended", "The contest has ended")
    contestId = contest.id
  }

  // 限流，位置与旧后端 submission/views/oj.py 的 SubmissionAPI.post 一致：
  // 比赛权限校验之后、取题目之前，按用户 id 消耗一个令牌。判题沙箱是有限资源。
  const throttle = await consumeToken("user", String(c.get("user")!.id))
  if (!throttle.allowed) {
    return failure(
      c,
      429,
      "too-many-submissions",
      `Please wait ${Math.floor(throttle.wait)} seconds`,
    )
  }

  const [problem] = await db
    .select({
      id: schema.problem.id,
      languages: schema.problem.languages,
    })
    .from(schema.problem)
    .where(
      and(
        eq(schema.problem.id, parsed.data.problemId),
        eq(schema.problem.visible, true),
        contestId === null
          ? isNull(schema.problem.contestId)
          : eq(schema.problem.contestId, contestId),
      ),
    )
    .limit(1)

  if (!problem) return failure(c, 404, "problem-not-found", "Problem does not exist")
  if (!problem.languages.includes(parsed.data.language)) {
    return failure(
      c,
      400,
      "language-not-allowed",
      `${parsed.data.language} is not allowed in the problem`,
    )
  }

  // 来源题单：前端只在 /problemset/:id/problem/:pid 那个入口带上它，落库纯粹是为了
  // 在提交列表里标出「这条是刷题单刷出来的」。校验只确认这道题确实在那个题单里 ——
  // 不查 visible / status，因为藏起来的题单里还困着已加入的学生（他们照样在做题），
  // 也不查有没有加入：没加入照样能从题单页点进题目，标记来源不该比入口本身更严。
  // 对不上就当没带，提交照收：来源标记错了顶多列表少个标签，不值得挡下一次提交。
  let problemsetId: number | null = null
  if (contestId === null && parsed.data.problemSetId) {
    const [link] = await db
      .select({ id: schema.problemsetProblem.id })
      .from(schema.problemsetProblem)
      .where(
        and(
          eq(schema.problemsetProblem.problemsetId, parsed.data.problemSetId),
          eq(schema.problemsetProblem.problemId, problem.id),
        ),
      )
      .limit(1)
    if (link) problemsetId = parsed.data.problemSetId
  }

  const user = c.get("user")!
  const submissionId = randomBytes(16).toString("hex")
  const createTime = new Date().toISOString()

  await db.insert(schema.submission).values({
    id: submissionId,
    problemId: problem.id,
    problemsetId,
    createTime,
    userId: user.id,
    username: user.username,
    code: parsed.data.code,
    result: JudgeStatus.PENDING,
    info: {},
    language: parsed.data.language,
    statisticInfo: {},
    contestId,
  })

  if (parsed.data.trace)
    await saveTrace(submissionId, user.id, problem.id, createTime, parsed.data.trace)

  try {
    await judgeQueue.add("judge", { submissionId, problemId: problem.id }, { jobId: submissionId })
  } catch (error) {
    await db
      .update(schema.submission)
      .set({ result: JudgeStatus.SYSTEM_ERROR })
      .where(eq(schema.submission.id, submissionId))
    console.error("Failed to enqueue submission", error)
    return failure(c, 502, "queue-unavailable", "Judge queue is unavailable")
  }

  return success(c, { submissionId } satisfies CreateSubmissionResponse, 201)
})

submissionRoutes.get("/submissions/today-count", async (c) => {
  const language = c.req.query("language")
  if (language === "Flowchart") {
    const [row] = await db
      .select({ value: count() })
      .from(schema.flowchartSubmission)
      .where(sql`${schema.flowchartSubmission.createTime} >= ${dayStart()}`)
    return success(c, row?.value ?? 0)
  }
  const [row] = await db
    .select({ value: count() })
    .from(schema.submission)
    .where(
      and(
        isNull(schema.submission.contestId),
        sql`${schema.submission.createTime} >= ${dayStart()}`,
      ),
    )
  return success(c, row?.value ?? 0)
})

submissionRoutes.route("/", submissionStatisticsRoutes)

// 老师也能重判：旧栈只给超管，前端却一直给老师亮着按钮，老师点了只会「权限不足」。
// 流程图那边老师本来就能重新评分，两边对齐。比赛提交不在此列（下面 isNull(contestId)）
submissionRoutes.post("/submissions/:id/rejudge", requireTeacher, async (c) => {
  const [row] = await db
    .select({
      id: schema.submission.id,
      problemId: schema.submission.problemId,
      result: schema.submission.result,
    })
    .from(schema.submission)
    .where(and(eq(schema.submission.id, c.req.param("id")), isNull(schema.submission.contestId)))
    .limit(1)
  if (!row) return failure(c, 404, "submission-not-found", "Submission does not exist")

  // info 一起清：不清的话判题中那几秒，列表和详情按旧的逐点结果算出「通过 2/3」
  await db
    .update(schema.submission)
    .set({ statisticInfo: {}, info: {}, result: JudgeStatus.PENDING })
    .where(eq(schema.submission.id, row.id))

  // jobId 必须带时间戳。队列保留最近 100 个已完成任务，沿用 submissionId 做 jobId 的话
  // BullMQ 会认为这个任务已经存在，重判静默变成空操作。与 flowcharts/:id/retry 同一处理。
  await judgeQueue.add(
    "judge",
    // 带上重判之前的结果，落库时只做差量（见 judge/run.ts 的 persistResult）
    { submissionId: row.id, problemId: row.problemId, rejudgedFrom: row.result },
    { jobId: `${row.id}:rejudge:${Date.now()}` },
  )
  return success(c, null)
})

submissionRoutes.post("/code/format", requireAuth, async (c) => {
  const parsed = await parseBody(c, formatCodeRequestSchema, "Invalid format payload")
  if (!parsed.success) return parsed.response
  // C / C++ 编不过就原样返回，不格式化（理由见 judge/run.ts 的 compileFails）。
  // 代码照常提交、照常判成编译错误，只是不改动学生的代码
  const { code: source, language, problemId } = parsed.data
  if (language === "c" || language === "cpp") {
    const judgeLanguage = language === "c" ? "C" : "C++"
    const [problem] =
      problemId === undefined
        ? []
        : await db
            .select({ template: schema.problem.template })
            .from(schema.problem)
            .where(eq(schema.problem.id, problemId))
            .limit(1)
    const rawTemplate = problem ? templateForLanguage(problem.template, judgeLanguage) : null
    const template = rawTemplate ? parseProblemTemplate(rawTemplate) : null
    const full = template ? `${template.prepend}\n${source}\n${template.append}` : source
    if (await compileFails(judgeLanguage, full)) {
      return success(c, { code: source } satisfies FormatCodeResponse)
    }
  }
  try {
    const code = await formatCode(source, language)
    return success(c, { code } satisfies FormatCodeResponse)
  } catch (error) {
    if (error instanceof CodeFormatError) {
      return failure(
        c,
        error.kind === "syntax" ? 400 : 500,
        // syntax-error 的 message 是 CPython 的报错原文，前端拿去翻成中文
        error.kind === "syntax" ? "syntax-error" : "format-tool-error",
        error.message,
      )
    }
    throw error
  }
})

// 参数按「实际用到的字段」声明，而不是整行 $inferSelect：列表接口只 select 需要的列，
// 传不进完整行。完整行在结构上满足这两个窄类型，详情接口照旧调用不受影响。
function canViewSubmission(
  user: AuthUser | null,
  row: { userId: number; problemId: number; createTime: string },
  problem: { createdById: number },
  problemSetCutoffs?: Map<number, string>,
) {
  if (!user) return false
  // 题单防作弊，见 problemSetLockCutoffs。只对学生自己的提交生效，老师不受限。
  // 学生管理员算学生，同样受限（旧后端 `is_regular_user()` 放过了他）。
  if (row.userId === user.id && !isTeacherOrAbove(user)) {
    const cutoff = problemSetCutoffs?.get(row.problemId)
    if (cutoff !== undefined && Date.parse(row.createTime) < Date.parse(cutoff)) return false
  }
  // 看别人代码的角色捷径只给老师和超管。学生管理员算学生（STUDENT_ROLES）：他参赛、上榜、
  // 和同学做同一份作业，能读别人的提交就是开卷。旧后端这里是 `not user.is_regular_user()`，
  // 学生管理员同样放行；OJ2 先收紧到「比赛没结束时不给」，现在整条都不给。
  //
  // 只掐角色捷径，不掐 `problem.createdById === user.id`：那是这道题的作者本人，
  // 他早就知道答案了，挡他没有意义。
  const elevated = isTeacherOrAbove(user)
  // 这三条就是全部：别人的代码谁都看不到，比赛内外一样。
  // 分享功能（problem.share_submission 题目级 / submission.shared 单条）已经删掉，
  // 原来结尾的 `return problem.shareSubmission || row.shared` 随之消失；它上面那条
  // 「比赛未结束一律不给」也一并去掉 —— 走到那里的必然不是本人/管理员/作者，
  // 现在无论比赛与否都是 false，留着是重复的。
  return row.userId === user.id || elevated || problem.createdById === user.id
}

/**
 * 提交列表只取序列化用得到的列。取 `submission.*` / `problem.*` 会把
 * submission.code（学生源码）、info、ip 和 problem 的 description / input_description /
 * output_description / hint / samples / answers / flowchart_data / sql_display 一并拉回来，
 * 这些字段列表一个都不用，纯属白传。
 */
const submissionListColumns = {
  submission: {
    id: schema.submission.id,
    createTime: schema.submission.createTime,
    userId: schema.submission.userId,
    // 题单闸门要按题定位，序列化本身用不到它
    problemId: schema.submission.problemId,
    /**
     * 显示**当前**用户名，和统计面板、个人主页对齐。列表里读的那份是提交时冻结的
     * 快照，改过名的学生会显示旧名字 —— 按 `ks248` 筛出来的行却写着
     * `ks24数媒1班ksXXX`，看着像筛错了。
     *
     * 已删号的学生 user 表里没有行，退回冻结的那份（否则整列空着）。
     */
    username: sql<string>`coalesce(${schema.user.username}, ${schema.submission.username})`,
    className: schema.user.className,
    result: schema.submission.result,
    language: schema.submission.language,
    statisticInfo: schema.submission.statisticInfo,
    // 只取 id，题单标题按页单独查一次（见 /submissions）——把 problemset 一起 join 进来
    // 会动到下面那条调过的分页查询，而每页最多两三个不同的题单，PK 查一次更便宜
    problemsetId: schema.submission.problemsetId,
    /**
     * 通过的测试点数 / 总数，口径同 caseSummary()：只认 info.data 是数组、逐项 result 为 0。
     * 在库里数完只回两个整数 —— info 带着每个点的 output_md5，整列拉回来只为数个数不值当
     */
    casesTotal: sql<
      number | null
    >`case when jsonb_typeof(${schema.submission.info} -> 'data') = 'array'
      then jsonb_array_length(${schema.submission.info} -> 'data') end`,
    casesPassed: sql<
      number | null
    >`case when jsonb_typeof(${schema.submission.info} -> 'data') = 'array'
      then (select count(*)::int from jsonb_array_elements(${schema.submission.info} -> 'data') as item
        where item ->> 'result' = '0') end`,
  },
  problem: {
    displayId: schema.problem.displayId,
    title: schema.problem.title,
    createdById: schema.problem.createdById,
  },
} as const

/**
 * 从判题原文里数出通过的测试点，为 null 的情形见契约 `caseSummary` 的注释。
 * 这里只信「有没有 data 数组」，数组项的形状信判题机，和前端 submissionCaseResults 同口径。
 */
function caseSummary(submission: typeof schema.submission.$inferSelect) {
  if (submission.contestId !== null || submission.language === "SQL") return null
  const data = asRecord(submission.info).data
  if (!Array.isArray(data) || data.length === 0) return null
  const passed = data.filter((item) => asRecord(item).result === JudgeStatus.ACCEPTED).length
  return { passed, total: data.length }
}

/** 列表行的 caseSummary：SQL 里数好的两个数，为 null 的情形和详情一致（SQL 题、没有逐点结果） */
function listCaseSummary(row: {
  language: string
  casesTotal: number | null
  casesPassed: number | null
}) {
  if (row.language === "SQL" || !row.casesTotal) return null
  return { passed: row.casesPassed ?? 0, total: row.casesTotal }
}

/**
 * 提交详情。三种结局：没有这条（404）、别人的代码看不到（403）、能看 —— 能看里又分自己的
 * 代码在题单布置期内藏着（showLink: false，代码不给、别的照给，页面摆出是谁哪道题什么结果）。
 */
async function submissionDetail(id: string, user: AuthUser, withAttempts: boolean) {
  const [row] = await db
    .select({
      submission: schema.submission,
      problem: schema.problem,
      // 当前用户名 / 班级，和提交列表同口径；已删号的学生 user 表里没有行
      currentUsername: schema.user.username,
      className: schema.user.className,
      problemSetTitle: schema.problemset.title,
    })
    .from(schema.submission)
    .innerJoin(schema.problem, eq(schema.submission.problemId, schema.problem.id))
    .leftJoin(schema.user, eq(schema.user.id, schema.submission.userId))
    .leftJoin(schema.problemset, eq(schema.problemset.id, schema.submission.problemsetId))
    .where(eq(schema.submission.id, id))
    .limit(1)
  if (!row) return { status: "not-found" } as const
  const own = row.submission.userId === user.id
  // 详情也要过闸门。旧后端只挡了列表里的链接，`SubmissionAPI.get`（views/oj.py:103）
  // 光走 check_user_permission——知道 submission id 直接访问照样拿得到代码，遮挡是虚的。
  const cutoffs =
    isTeacherOrAbove(user) || !own
      ? undefined
      : await problemSetLockCutoffs(user.id, [row.submission.problemId])
  const visible = canViewSubmission(user, row.submission, row.problem, cutoffs)
  // 走到这里还看不了、又是自己的，只剩题单布置期这一种（见 canViewSubmission）
  if (!visible && !own) return { status: "forbidden" } as const
  // info（含每个测试点的 test_case 编号与 output_md5）只给管理员，对齐旧后端：
  // submission/views/oj.py 用 is_admin_role() 在 SubmissionModelSerializer 与
  // SubmissionSafeModelSerializer 之间二选一，把关的是角色，不是「是不是自己的提交」。
  const full = isAdminRole(user) && visible
  const attempts = withAttempts
    ? await db
        .select({
          id: schema.submission.id,
          createTime: schema.submission.createTime,
          userId: schema.submission.userId,
          problemId: schema.submission.problemId,
          result: schema.submission.result,
        })
        .from(schema.submission)
        .where(
          and(
            eq(schema.submission.userId, row.submission.userId),
            eq(schema.submission.problemId, row.submission.problemId),
            row.submission.contestId === null
              ? isNull(schema.submission.contestId)
              : eq(schema.submission.contestId, row.submission.contestId),
          ),
        )
        .orderBy(schema.submission.createTime, schema.submission.id)
        .limit(200)
    : null
  return {
    status: "ok",
    data: {
      id: row.submission.id,
      createTime: row.submission.createTime,
      userId: row.submission.userId,
      username: row.currentUsername ?? row.submission.username,
      code: visible ? row.submission.code : "",
      result: row.submission.result,
      info: full ? row.submission.info : {},
      language: row.submission.language,
      statisticInfo: visible ? asRecord(row.submission.statisticInfo) : {},
      // contest 也在旧后端的排除名单里，同样只给管理员。提交者本人例外：他知道自己在哪场比赛
      // 里交的，不给的话独立页面上「复制回到题目」「题目链接」只能拼出题库的
      // /problem/<题号> —— 比赛里的题号是比赛自己的，指到的是另一道题
      contestId: full || own ? row.submission.contestId : null,
      problemId: row.submission.problemId,
      // problem 表本来就 join 了，不额外查库
      problemDisplayId: row.problem.displayId,
      problemTitle: row.problem.title,
      className: row.className,
      problemSet:
        row.submission.problemsetId !== null && row.problemSetTitle !== null
          ? { id: row.submission.problemsetId, title: row.problemSetTitle }
          : null,
      showLink: visible,
      caseSummary: visible ? caseSummary(row.submission) : null,
      attempts:
        attempts?.map((item) => ({
          id: item.id,
          createTime: item.createTime,
          result: item.result,
          showLink: canViewSubmission(user, item, row.problem, cutoffs),
        })) ?? null,
    } satisfies SubmissionDetail,
  } as const
}

/**
 * 提交列表取数据。深翻页不走 `LIMIT n OFFSET m`——Postgres 对 OFFSET 没有捷径，前 m 行
 * 必须真的产出再丢掉，而丢弃发生在 join 之后，每一行都白回了一次表。生产快照（10.4 万条
 * 公开提交）上最后一页实测 1258ms、碰了 95347 个 buffer。而且越早的页越慢：平时没人翻，
 * 那些数据页从来不在 shared_buffers 里，全是冷读。
 *
 * 拆成两步就便宜得多：
 *   1. 只 select create_time / id —— 正好是 submission_public_create_time_id_idx 的两列，
 *      跳过 m 行走 Index Only Scan，Heap Fetches 为 0，纯在索引页里数数；
 *   2. 拿这一行当游标做 keyset 回查，只回表取 limit 行。
 * 同一页实测降到约 9ms、885 个 buffer。代价变成 O(m) 个**索引条目**而不是堆页，按快照里
 * 的索引密度外推，涨到 100 万条时最深一页仍在几十毫秒量级。
 *
 * 排序必须带 id：create_time 只有毫秒精度（`new Date().toISOString()`），光靠它不是全序，
 * 游标用 `<=` 回查时同毫秒的上一页末行会重复出现在下一页页首。索引已按 (create_time DESC,
 * id DESC) 建好，带上 id 不会多出 Sort 节点。
 *
 * offset 为 0 时没有可跳过的行，直接取，省一次往返。
 *
 * **按用户名筛选另走一条路**：先把匹配的行整个圈出来（`materialized` 挡住规划器），
 * 在圈里排序取页，再按主键回表。不圈的话规划器一见 `ORDER BY ... LIMIT` 就选时间索引
 * 倒扫、边扫边滤——它按平均密度估一个班的提交散布在全表，实际上一个班的提交扎堆在它
 * 上课的那一两年，早就毕业的班要倒扫大半张表。快照实测第一页：ks248 66ms → 0.75ms、
 * ks225 142ms → 2.7ms、ks212 翻到 1000 条 79ms → 3.6ms。圈的代价和匹配行数成正比，
 * 最宽的 `ks2`（9.5 万行）要 65ms，和同一请求里 count 扫表的量级一样，不另外拖慢响应。
 * 游标那条路帮不了它：第一步游标定位本身就是同一个倒扫。
 */
async function paginateSubmissionRows(
  where: SQL | undefined,
  limit: number,
  offset: number,
  byUsername: boolean,
) {
  const order = [desc(schema.submission.createTime), desc(schema.submission.id)] as const
  const page = (condition: SQL | undefined) =>
    db
      .select(submissionListColumns)
      .from(schema.submission)
      .innerJoin(schema.problem, eq(schema.submission.problemId, schema.problem.id))
      // 取当前用户名用。left join 不是 inner —— 已删号的学生这边没有行，
      // inner join 会把他们的提交整条从列表里抹掉
      .leftJoin(schema.user, eq(schema.user.id, schema.submission.userId))
      .where(condition)
      .orderBy(...order)
      .limit(limit)

  if (byUsername) {
    const matched = db
      .select({
        id: schema.submission.id,
        createTime: schema.submission.createTime,
      })
      .from(schema.submission)
      .where(where)
    return page(sql`${schema.submission.id} in (
      with matched as materialized ${matched}
      select id from matched order by create_time desc, id desc limit ${limit} offset ${offset}
    )`)
  }
  if (offset === 0) return page(where)

  const [boundary] = await db
    .select({
      createTime: schema.submission.createTime,
      id: schema.submission.id,
    })
    .from(schema.submission)
    .where(where)
    .orderBy(...order)
    .limit(1)
    .offset(offset)
  // offset 越过了结果集尾巴，这一页本来就该是空的
  if (!boundary) return []

  return page(
    and(
      where,
      sql`(${schema.submission.createTime}, ${schema.submission.id}) <= (${boundary.createTime}::timestamptz, ${boundary.id}::text)`,
    ),
  )
}

/**
 * 这一页里出现过的来源题单，id → 标题。传进来的数组允许带 null 和重复值。
 * 一页最多 250 行、实际能落到的题单数是个位数，按主键 IN 查一次就完了。
 */
async function problemsetTitleMap(ids: Array<number | null>) {
  const unique = [...new Set(ids.filter((id): id is number => id !== null))]
  if (unique.length === 0) return new Map<number, string>()
  const rows = await db
    .select({ id: schema.problemset.id, title: schema.problemset.title })
    .from(schema.problemset)
    .where(inArray(schema.problemset.id, unique))
  return new Map(rows.map((row) => [row.id, row.title]))
}

submissionRoutes.get("/submissions", optionalAuth, async (c) => {
  const limit = queryInteger(c.req.query("limit"), 10, { min: 1, max: 250 })
  const offset = queryInteger(c.req.query("offset"), 0, { min: 0 })
  const user = c.get("user")
  // 「非管理员即受限」，不能写成「是普通用户才受限」——
  // 后者对匿名用户（user 为 null）会短路，匿名反而能看到全部提交，权限大于登录学生。
  if (!(await getBooleanOption("submission_list_show_all", true)) && !isAdminRole(user)) {
    return success(c, { results: [], total: 0, unknownProblems: [] } satisfies SubmissionList)
  }
  const displayId = c.req.query("problemDisplayId")?.trim()
  const myself = c.req.query("myself") === "1" ? user : null
  // 「只看自己」盖过用户名
  const username = myself ? undefined : c.req.query("username")?.trim()
  const result = c.req.query("result")
  const language = c.req.query("language")?.trim()
  // 班级（user.class_name），和用户名可以同时用：「25计算机3班里名字带『王』的」
  const className = myself ? undefined : c.req.query("className")?.trim()
  const filters: Array<SQL | undefined> = [isNull(schema.submission.contestId)]
  filters.push(
    ...(await Promise.all([
      displayId ? problemFilter(displayId, null) : undefined,
      className ? classNameFilter(className) : undefined,
      username
        ? c.req.query("exactUsername") === "1"
          ? exactUsernameFilter(username)
          : usernameFilter(username)
        : undefined,
    ])),
  )
  if (myself) filters.push(eq(schema.submission.userId, myself.id))
  if (result !== undefined && result !== "" && Number.isInteger(Number(result)))
    filters.push(eq(schema.submission.result, asFilterValue(Number(result))))
  if (language) filters.push(eq(schema.submission.language, asFilterValue(language)))
  if (c.req.query("today") === "1")
    filters.push(sql`${schema.submission.createTime} >= ${dayStart()}`)
  const where = and(...filters)
  // count 不 join problem：无条件 join 会让计划器把 count 退化成 seq scan
  // （生产快照实测 7.5ms → 78ms）。题号已经解析成 problem_id，也用不着 join。
  const [totalRows, rows, unknownProblems] = await Promise.all([
    db.select({ value: count() }).from(schema.submission).where(where),
    // 班级和用户名一样是「圈一小撮人」，走同一条圈选路（见 paginateSubmissionRows）
    paginateSubmissionRows(where, limit, offset, Boolean(username || className)),
    displayId ? unknownDisplayIds(displayId, null) : [],
  ])
  // 闸门只对学生自己的提交生效，所以只拿这一页里属于他自己的题目去查，一页一次查询
  const [cutoffs, problemsetTitles] = await Promise.all([
    user && !isTeacherOrAbove(user)
      ? problemSetLockCutoffs(user.id, [
          ...new Set(
            rows
              .filter((row) => row.submission.userId === user.id)
              .map((row) => row.submission.problemId),
          ),
        ])
      : undefined,
    // 来源题单的标题。一页里不同题单最多几个，按主键查一次就够
    problemsetTitleMap(rows.map((row) => row.submission.problemsetId)),
  ])
  return success(c, {
    results: rows.map(
      ({ submission, problem }) =>
        ({
          id: submission.id,
          problemDisplayId: problem.displayId,
          problemTitle: problem.title,
          showLink: user ? canViewSubmission(user, submission, problem, cutoffs) : false,
          createTime: submission.createTime,
          userId: submission.userId,
          username: submission.username,
          className: submission.className || null,
          result: submission.result,
          language: submission.language,
          statisticInfo: asRecord(submission.statisticInfo),
          // 题单被删掉之后外键把 problemset_id 置了空，这里自然就没标记了
          problemSet:
            submission.problemsetId !== null && problemsetTitles.has(submission.problemsetId)
              ? {
                  id: submission.problemsetId,
                  title: problemsetTitles.get(submission.problemsetId)!,
                }
              : null,
          caseSummary: listCaseSummary(submission),
        }) satisfies SubmissionListItem,
    ),
    total: totalRows[0]?.value ?? 0,
    unknownProblems,
  } satisfies SubmissionList)
})

submissionRoutes.get(
  "/contests/:contestId/submissions",
  optionalAuth,
  requireContestAccess("submissions", "contestId"),
  async (c) => {
    const contest = c.get("contest")!
    const limit = queryInteger(c.req.query("limit"), 10, { min: 1, max: 250 })
    const offset = queryInteger(c.req.query("offset"), 0, { min: 0 })
    const user = c.get("user")
    const displayId = c.req.query("problemDisplayId")?.trim()
    const myself = c.req.query("myself") === "1" ? user : null
    const username = myself ? undefined : c.req.query("username")?.trim()
    const result = c.req.query("result")
    const filters: Array<SQL | undefined> = [eq(schema.submission.contestId, contest.id)]
    filters.push(
      ...(await Promise.all([
        displayId ? problemFilter(displayId, contest.id) : undefined,
        username ? usernameFilter(username) : undefined,
      ])),
    )
    if (myself) filters.push(eq(schema.submission.userId, myself.id))
    if (result !== undefined && result !== "" && Number.isInteger(Number(result)))
      filters.push(eq(schema.submission.result, asFilterValue(Number(result))))
    if (contestStatus(contest) !== "1")
      filters.push(sql`${schema.submission.createTime} >= ${contest.startTime}`)
    const where = and(...filters)
    // 一场比赛最多一两千条提交，按 contest_create_time_idx 定位之后怎么滤都不贵，
    // 所以不像公开列表那样分游标 / 圈选两条路
    const [totalRows, rows, unknownProblems] = await Promise.all([
      db.select({ value: count() }).from(schema.submission).where(where),
      db
        .select(submissionListColumns)
        .from(schema.submission)
        .innerJoin(schema.problem, eq(schema.submission.problemId, schema.problem.id))
        .leftJoin(schema.user, eq(schema.user.id, schema.submission.userId))
        .where(where)
        .orderBy(desc(schema.submission.createTime))
        .limit(limit)
        .offset(offset),
      displayId ? unknownDisplayIds(displayId, contest.id) : [],
    ])
    // 这里不挂题单防作弊闸门（对比公开列表）：题单里的题必定是非比赛题——加题时卡了
    // `isNull(problem.contestId)`（admin/problemset.ts:232）——而这条列表只出比赛提交，
    // 两边交集恒空，挂上去就是每页白跑一次查询，而比赛进行中这条列表是被刷得最狠的。
    // 旧后端 ContestSubmissionListAPI 照抄了 bulk_fetch，那边同样是死代码。
    return success(c, {
      results: rows.map(
        ({ submission, problem }) =>
          ({
            id: submission.id,
            problemDisplayId: problem.displayId,
            problemTitle: problem.title,
            showLink: user ? canViewSubmission(user, submission, problem) : false,
            createTime: submission.createTime,
            userId: submission.userId,
            username: submission.username,
            className: submission.className || null,
            result: submission.result,
            language: submission.language,
            statisticInfo: asRecord(submission.statisticInfo),
            // 比赛提交没有来源题单：题单只收非比赛题（admin/problemset.ts 加题时卡了
            // isNull(problem.contestId)），提交接口那边也只在 contestId 为空时才认这个字段
            problemSet: null,
            // 比赛只报对错，不给通过几个点（口径见契约 caseSummarySchema）
            caseSummary: null,
          }) satisfies SubmissionListItem,
      ),
      total: totalRows[0]?.value ?? 0,
      unknownProblems,
    } satisfies SubmissionList)
  },
)

submissionRoutes.get("/submissions/:id", requireAuth, async (c) => {
  const user = c.get("user")!
  const detail = await submissionDetail(c.req.param("id"), user, c.req.query("attempts") === "1")
  if (detail.status === "not-found") {
    return failure(c, 404, "submission-not-found", "Submission does not exist")
  }
  // 原来看不到也回 404，独立页面分不清「链接不对」和「别人的」，只能一直转圈
  if (detail.status === "forbidden") {
    return failure(c, 403, "submission-forbidden", "No permission to view this submission")
  }
  return success(c, detail.data)
})