feat(admin): add bulk rejudge for game submissions

Extract common rejudge logic into a helper method and add two new
endpoints: rejudge-latest (per-user latest only) and rejudge-all.
This allows re-running submissions in bulk after testcase changes.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

6 files changed, 249 insertions, 10 deletions

diff --git a/backend/admin/handler.go b/backend/admin/handler.go
index c8ddd25..9bdeb69 100644
--- a/backend/admin/handler.go
+++ b/backend/admin/handler.go
@@ -72,6 +72,8 @@ func (h *Handler) RegisterHandlers(g *echo.Group) {
 	g.POST("/games/:gameID", h.postGameEdit)
 	g.POST("/games/:gameID/start", h.postGameStart)
 	g.GET("/games/:gameID/submissions", h.getSubmissions)
+	g.POST("/games/:gameID/submissions/rejudge-latest", h.postSubmissionsRejudgeLatest)
+	g.POST("/games/:gameID/submissions/rejudge-all", h.postSubmissionsRejudgeAll)
 	g.GET("/games/:gameID/submissions/:submissionID", h.getSubmissionDetail)
 	g.POST("/games/:gameID/submissions/:submissionID/rejudge", h.postSubmissionRejudge)
 
@@ -671,6 +673,22 @@ func (h *Handler) getSubmissionDetail(c echo.Context) error {
 	})
 }
 
+func (h *Handler) rejudgeSubmission(ctx context.Context, submission db.Submission, language string) error {
+	err := h.txm.RunInTx(ctx, func(qtx db.Querier) error {
+		if err := qtx.DeleteTestcaseResultsBySubmissionID(ctx, submission.SubmissionID); err != nil {
+			return err
+		}
+		return qtx.UpdateSubmissionStatus(ctx, db.UpdateSubmissionStatusParams{
+			SubmissionID: submission.SubmissionID,
+			Status:       "running",
+		})
+	})
+	if err != nil {
+		return err
+	}
+	return h.hub.EnqueueTestTasks(ctx, int(submission.SubmissionID), int(submission.GameID), int(submission.UserID), language, submission.Code)
+}
+
 func (h *Handler) postSubmissionRejudge(c echo.Context) error {
 	gameID, err := strconv.Atoi(c.Param("gameID"))
 	if err != nil {
@@ -700,25 +718,71 @@ func (h *Handler) postSubmissionRejudge(c echo.Context) error {
 		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
 	}
 
-	err = h.txm.RunInTx(ctx, func(qtx db.Querier) error {
-		if err := qtx.DeleteTestcaseResultsBySubmissionID(ctx, int32(submissionID)); err != nil {
-			return err
+	if err := h.rejudgeSubmission(ctx, submission, game.Language); err != nil {
+		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+	}
+
+	return c.Redirect(http.StatusSeeOther, fmt.Sprintf("%sadmin/games/%d/submissions/%d", h.conf.BasePath, gameID, submissionID))
+}
+
+func (h *Handler) postSubmissionsRejudgeLatest(c echo.Context) error {
+	gameID, err := strconv.Atoi(c.Param("gameID"))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid game_id")
+	}
+
+	ctx := c.Request().Context()
+
+	game, err := h.q.GetGameByID(ctx, int32(gameID))
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return echo.NewHTTPError(http.StatusNotFound)
 		}
-		return qtx.UpdateSubmissionStatus(ctx, db.UpdateSubmissionStatusParams{
-			SubmissionID: int32(submissionID),
-			Status:       "running",
-		})
-	})
+		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+	}
+
+	submissions, err := h.q.GetLatestSubmissionsByGameID(ctx, int32(gameID))
 	if err != nil {
 		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
 	}
 
-	err = h.hub.EnqueueTestTasks(ctx, submissionID, gameID, int(submission.UserID), game.Language, submission.Code)
+	for _, s := range submissions {
+		if err := h.rejudgeSubmission(ctx, s, game.Language); err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+		}
+	}
+
+	return c.Redirect(http.StatusSeeOther, fmt.Sprintf("%sadmin/games/%d/submissions", h.conf.BasePath, gameID))
+}
+
+func (h *Handler) postSubmissionsRejudgeAll(c echo.Context) error {
+	gameID, err := strconv.Atoi(c.Param("gameID"))
 	if err != nil {
+		return echo.NewHTTPError(http.StatusBadRequest, "Invalid game_id")
+	}
+
+	ctx := c.Request().Context()
+
+	game, err := h.q.GetGameByID(ctx, int32(gameID))
+	if err != nil {
+		if errors.Is(err, pgx.ErrNoRows) {
+			return echo.NewHTTPError(http.StatusNotFound)
+		}
 		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
 	}
 
-	return c.Redirect(http.StatusSeeOther, fmt.Sprintf("%sadmin/games/%d/submissions/%d", h.conf.BasePath, gameID, submissionID))
+	submissions, err := h.q.GetSubmissionsByGameID(ctx, int32(gameID))
+	if err != nil {
+		return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+	}
+
+	for _, s := range submissions {
+		if err := h.rejudgeSubmission(ctx, s, game.Language); err != nil {
+			return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
+		}
+	}
+
+	return c.Redirect(http.StatusSeeOther, fmt.Sprintf("%sadmin/games/%d/submissions", h.conf.BasePath, gameID))
 }
 
 func (h *Handler) getProblems(c echo.Context) error {
diff --git a/backend/admin/handler_test.go b/backend/admin/handler_test.go
index 3b7a2ba..7249c2b 100644
--- a/backend/admin/handler_test.go
+++ b/backend/admin/handler_test.go
@@ -41,6 +41,7 @@ type mockQuerier struct {
 	listMainPlayersFunc                     func(ctx context.Context, gameIDs []int32) ([]db.ListMainPlayersRow, error)
 	listSubmissionIDsFunc                   func(ctx context.Context) ([]int32, error)
 	getSubmissionsByGameIDFunc              func(ctx context.Context, gameID int32) ([]db.Submission, error)
+	getLatestSubmissionsByGameIDFunc        func(ctx context.Context, gameID int32) ([]db.Submission, error)
 	getSubmissionByIDFunc                   func(ctx context.Context, submissionID int32) (db.Submission, error)
 	getTestcaseResultsBySubmIDFunc          func(ctx context.Context, submissionID int32) ([]db.TestcaseResult, error)
 	updateSubmissionStatusFunc              func(ctx context.Context, arg db.UpdateSubmissionStatusParams) error
@@ -184,6 +185,13 @@ func (m *mockQuerier) GetSubmissionsByGameID(ctx context.Context, gameID int32)
 	return nil, nil
 }
 
+func (m *mockQuerier) GetLatestSubmissionsByGameID(ctx context.Context, gameID int32) ([]db.Submission, error) {
+	if m.getLatestSubmissionsByGameIDFunc != nil {
+		return m.getLatestSubmissionsByGameIDFunc(ctx, gameID)
+	}
+	return nil, nil
+}
+
 func (m *mockQuerier) GetSubmissionByID(ctx context.Context, submissionID int32) (db.Submission, error) {
 	if m.getSubmissionByIDFunc != nil {
 		return m.getSubmissionByIDFunc(ctx, submissionID)
@@ -1499,3 +1507,122 @@ func TestPostSubmissionRejudge_SubmissionNotFound(t *testing.T) {
 		t.Errorf("status = %d, want %d", httpErr.Code, http.StatusNotFound)
 	}
 }
+
+func TestPostSubmissionsRejudgeLatest_Success(t *testing.T) {
+	var enqueuedIDs []int
+
+	q := &mockQuerier{
+		getGameByIDFunc: func(_ context.Context, gameID int32) (db.GetGameByIDRow, error) {
+			return db.GetGameByIDRow{GameID: gameID, ProblemID: 1, Language: "php"}, nil
+		},
+		getLatestSubmissionsByGameIDFunc: func(_ context.Context, _ int32) ([]db.Submission, error) {
+			return []db.Submission{
+				{SubmissionID: 10, GameID: 1, UserID: 1, Code: "<?php echo 1;", CreatedAt: pgtype.Timestamp{Valid: true}},
+				{SubmissionID: 20, GameID: 1, UserID: 2, Code: "<?php echo 2;", CreatedAt: pgtype.Timestamp{Valid: true}},
+			}, nil
+		},
+	}
+
+	hub := &mockGameHub{
+		enqueueTestTasksFunc: func(_ context.Context, submissionID, _, _ int, _, _ string) error {
+			enqueuedIDs = append(enqueuedIDs, submissionID)
+			return nil
+		},
+	}
+
+	txm := &mockTxManager{
+		runInTxFunc: func(_ context.Context, fn func(q db.Querier) error) error {
+			return fn(&mockQuerier{})
+		},
+	}
+
+	h := &Handler{q: q, txm: txm, hub: hub, conf: &config.Config{BasePath: "/test/"}}
+
+	c, rec := newEchoContextWithForm("/admin/games/1/submissions/rejudge-latest", map[string]string{
+		"gameID": "1",
+	}, url.Values{})
+
+	err := h.postSubmissionsRejudgeLatest(c)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if rec.Code != http.StatusSeeOther {
+		t.Errorf("status = %d, want %d", rec.Code, http.StatusSeeOther)
+	}
+	if len(enqueuedIDs) != 2 {
+		t.Fatalf("enqueued count = %d, want 2", len(enqueuedIDs))
+	}
+	if enqueuedIDs[0] != 10 || enqueuedIDs[1] != 20 {
+		t.Errorf("enqueued IDs = %v, want [10, 20]", enqueuedIDs)
+	}
+}
+
+func TestPostSubmissionsRejudgeAll_Success(t *testing.T) {
+	var enqueuedIDs []int
+
+	q := &mockQuerier{
+		getGameByIDFunc: func(_ context.Context, gameID int32) (db.GetGameByIDRow, error) {
+			return db.GetGameByIDRow{GameID: gameID, ProblemID: 1, Language: "php"}, nil
+		},
+		getSubmissionsByGameIDFunc: func(_ context.Context, _ int32) ([]db.Submission, error) {
+			return []db.Submission{
+				{SubmissionID: 10, GameID: 1, UserID: 1, Code: "<?php echo 1;", CreatedAt: pgtype.Timestamp{Valid: true}},
+				{SubmissionID: 11, GameID: 1, UserID: 1, Code: "<?php echo 11;", CreatedAt: pgtype.Timestamp{Valid: true}},
+				{SubmissionID: 20, GameID: 1, UserID: 2, Code: "<?php echo 2;", CreatedAt: pgtype.Timestamp{Valid: true}},
+			}, nil
+		},
+	}
+
+	hub := &mockGameHub{
+		enqueueTestTasksFunc: func(_ context.Context, submissionID, _, _ int, _, _ string) error {
+			enqueuedIDs = append(enqueuedIDs, submissionID)
+			return nil
+		},
+	}
+
+	txm := &mockTxManager{
+		runInTxFunc: func(_ context.Context, fn func(q db.Querier) error) error {
+			return fn(&mockQuerier{})
+		},
+	}
+
+	h := &Handler{q: q, txm: txm, hub: hub, conf: &config.Config{BasePath: "/test/"}}
+
+	c, rec := newEchoContextWithForm("/admin/games/1/submissions/rejudge-all", map[string]string{
+		"gameID": "1",
+	}, url.Values{})
+
+	err := h.postSubmissionsRejudgeAll(c)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if rec.Code != http.StatusSeeOther {
+		t.Errorf("status = %d, want %d", rec.Code, http.StatusSeeOther)
+	}
+	if len(enqueuedIDs) != 3 {
+		t.Fatalf("enqueued count = %d, want 3", len(enqueuedIDs))
+	}
+	if enqueuedIDs[0] != 10 || enqueuedIDs[1] != 11 || enqueuedIDs[2] != 20 {
+		t.Errorf("enqueued IDs = %v, want [10, 11, 20]", enqueuedIDs)
+	}
+}
+
+func TestPostSubmissionsRejudgeAll_GameNotFound(t *testing.T) {
+	h := newTestHandler(&mockQuerier{})
+
+	c, _ := newEchoContextWithForm("/admin/games/999/submissions/rejudge-all", map[string]string{
+		"gameID": "999",
+	}, url.Values{})
+
+	err := h.postSubmissionsRejudgeAll(c)
+	if err == nil {
+		t.Fatal("expected error for non-existent game")
+	}
+	httpErr, ok := err.(*echo.HTTPError)
+	if !ok {
+		t.Fatalf("expected echo.HTTPError, got %T", err)
+	}
+	if httpErr.Code != http.StatusNotFound {
+		t.Errorf("status = %d, want %d", httpErr.Code, http.StatusNotFound)
+	}
+}
diff --git a/backend/admin/templates/submissions.html b/backend/admin/templates/submissions.html
index 6870c2a..c53c5b3 100644
--- a/backend/admin/templates/submissions.html
+++ b/backend/admin/templates/submissions.html
@@ -8,6 +8,12 @@
 
 {{ define "content" }}
 <h2>Submissions for Game {{ .GameID }}</h2>
+<form method="POST" action="{{ .BasePath }}admin/games/{{ .GameID }}/submissions/rejudge-latest" style="display:inline">
+  <button type="submit">Rejudge Latest</button>
+</form>
+<form method="POST" action="{{ .BasePath }}admin/games/{{ .GameID }}/submissions/rejudge-all" style="display:inline">
+  <button type="submit">Rejudge All</button>
+</form>
 <table>
   <thead>
     <tr>
diff --git a/backend/db/querier.go b/backend/db/querier.go
index 2b957ba..220a86c 100644
--- a/backend/db/querier.go
+++ b/backend/db/querier.go
@@ -31,6 +31,7 @@ type Querier interface {
 	GetGameByID(ctx context.Context, gameID int32) (GetGameByIDRow, error)
 	GetLatestState(ctx context.Context, arg GetLatestStateParams) (GetLatestStateRow, error)
 	GetLatestStatesOfMainPlayers(ctx context.Context, gameID int32) ([]GetLatestStatesOfMainPlayersRow, error)
+	GetLatestSubmissionsByGameID(ctx context.Context, gameID int32) ([]Submission, error)
 	GetProblemByID(ctx context.Context, problemID int32) (Problem, error)
 	GetQualifyingRanking(ctx context.Context, arg GetQualifyingRankingParams) ([]GetQualifyingRankingRow, error)
 	GetRanking(ctx context.Context, gameID int32) ([]GetRankingRow, error)
diff --git a/backend/db/query.sql.go b/backend/db/query.sql.go
index 8a13726..02f1abf 100644
--- a/backend/db/query.sql.go
+++ b/backend/db/query.sql.go
@@ -472,6 +472,41 @@ func (q *Queries) GetLatestStatesOfMainPlayers(ctx context.Context, gameID int32
 	return items, nil
 }
 
+const getLatestSubmissionsByGameID = `-- name: GetLatestSubmissionsByGameID :many
+SELECT DISTINCT ON (user_id) submission_id, game_id, user_id, code, code_size, status, created_at
+FROM submissions
+WHERE game_id = $1
+ORDER BY user_id, created_at DESC
+`
+
+func (q *Queries) GetLatestSubmissionsByGameID(ctx context.Context, gameID int32) ([]Submission, error) {
+	rows, err := q.db.Query(ctx, getLatestSubmissionsByGameID, gameID)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var items []Submission
+	for rows.Next() {
+		var i Submission
+		if err := rows.Scan(
+			&i.SubmissionID,
+			&i.GameID,
+			&i.UserID,
+			&i.Code,
+			&i.CodeSize,
+			&i.Status,
+			&i.CreatedAt,
+		); err != nil {
+			return nil, err
+		}
+		items = append(items, i)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	return items, nil
+}
+
 const getProblemByID = `-- name: GetProblemByID :one
 SELECT problem_id, title, description, language, sample_code FROM problems
 WHERE problem_id = $1
diff --git a/backend/query.sql b/backend/query.sql
index 1e49780..45ac46f 100644
--- a/backend/query.sql
+++ b/backend/query.sql
@@ -265,6 +265,12 @@ FROM submissions
 WHERE game_id = $1
 ORDER BY created_at DESC;
 
+-- name: GetLatestSubmissionsByGameID :many
+SELECT DISTINCT ON (user_id) *
+FROM submissions
+WHERE game_id = $1
+ORDER BY user_id, created_at DESC;
+
 -- name: GetSubmissionByID :one
 SELECT *
 FROM submissions