feat(enakgame): weekly leaderboard

GET /customer/enakgame/leaderboard ranks the customers of an organization by
the EnakCoin they won from games in one week, Monday to Sunday in
Asia/Jakarta. Only completed, unflagged sessions count, by the week they
started; entry cost is not subtracted. Equal totals rank by who reached
theirs first, so no two customers share a rank.

Optional date (any day of the week, this week by default), game_id and limit
(10, at most 100). The response holds the top ranks and, under me, the
customer asking wherever they rank. Other customers are shown by a masked
name: the first word whole, the others by their first letter; a word with a
digit keeps only its first character.

The EnakGame web game shows it: integration-enakgame.md §10 (checklist now
§11) and RFC §11. The DB test needs TEST_DATABASE_URL.

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

docs/integration-enakgame.md

@@ -1,6 +1,6 @@
 # Integrasi EnakGame: Game Client (Phaser)
 
-**Untuk:** tim game EnakGame (client Phaser) · **Base URL:** `/api/v1` · **Per:** 9 Okt 2026
+**Untuk:** tim game EnakGame (client Phaser) · **Base URL:** `/api/v1` · **Per:** 12 Okt 2026
 
 Kamu mengerjakan **game EnakGame**: game web (Phaser) yang dibuka aplikasi customer di
 dalam webview dari `game_url` sebuah game. Game inilah yang menjalankan satu kali main
@@ -13,7 +13,7 @@ Pembagian tugas dengan aplikasi customer:
 | Aplikasi customer ([`integration-mobile-customer.md`](./integration-mobile-customer.md)) | Game EnakGame (dokumen ini) |
 |---|---|
 | Login customer, menyimpan token | Menerima token dari aplikasi lewat bridge (§4); bila tidak ada, meminta customer login (§5) |
-| Daftar game, membuka `game_url` di webview | Start session, main, complete, tampilkan hadiah |
+| Daftar game, membuka `game_url` di webview | Start session, main, complete, tampilkan hadiah, leaderboard mingguan (§10) |
 | Saldo, riwayat, voucher, PIN | Memberi tahu aplikasi saat saldo berubah atau game ditutup |
 
 Alasan di balik aturannya ada di [`rfc-enakgame.md`](./rfc-enakgame.md) dan
@@ -106,6 +106,7 @@ memakai header `Authorization: Bearer <token>`. Request ber-body memakai
 | 3 | `POST /customer/enakgame/sessions/:id/complete` | – | `{ "score"?, "outcome"?, "data"? }` | Permainan selesai | §6.3 |
 | 4 | `GET /customer/enakgame/sessions/:id` | – | – | Pemulihan setelah reload, bila `session_id` tersimpan | §6.4 |
 | 5 | `GET /customer/enakgame/sessions?game_id=&status=&page=&limit=` | – | – | Pemulihan setelah reload, bila `session_id` tidak tersimpan | §6.4 |
+| 6 | `GET /customer/enakgame/leaderboard?date=&game_id=&limit=` | – | – | Layar leaderboard; muat ulang setelah complete | §10 |
 
 Game tidak memanggil endpoint lain. Registrasi, saldo, riwayat, voucher, dan PIN
 adalah tugas aplikasi customer.
@@ -601,7 +602,49 @@ saja.
 
 ---
 
-## 10. Checklist
+## 10. Leaderboard mingguan — `GET /customer/enakgame/leaderboard`
+
+Peringkat customer satu organisasi menurut EnakCoin yang dimenangkan dari game dalam
+satu minggu, Senin 00:00 sampai Minggu 23:59 WIB. Yang dihitung hanya session
+`COMPLETED`, menurut minggu saat session dimulai; entry cost tidak mengurangi. Total
+yang sama diurutkan menurut siapa yang mencapainya lebih dulu, jadi tidak ada peringkat
+kembar.
+
+| Query | Default | Keterangan |
+|---|---|---|
+| `date` | Minggu ini | Hari mana pun dalam minggu yang diminta, `YYYY-MM-DD`. Untuk minggu lalu, kirim tanggal 7 hari sebelum `week_start` minggu ini |
+| `game_id` | Semua game | Leaderboard satu game, mis. `game_id` dari `init` untuk "peringkat game ini" |
+| `limit` | 10 | Jumlah peringkat teratas, maks 100 |
+
+```json
+{
+  "week_start": "2026-10-12",
+  "week_end": "2026-10-18",
+  "game_id": null,
+  "entries": [
+    { "rank": 1, "name": "Budi S******", "coins": 120, "is_me": false },
+    { "rank": 2, "name": "Siti N** A*****", "coins": 90, "is_me": true }
+  ],
+  "me": { "rank": 2, "name": "Siti N** A*****", "coins": 90, "is_me": true }
+}
+```
+
+- Nama customer lain sudah disamarkan server: kata pertama utuh, kata berikutnya hanya
+  huruf pertama. Tampilkan apa adanya; untuk baris `is_me: true` tampilkan "Kamu".
+- `me` adalah posisi customer yang login, juga bila di luar `limit`: tampilkan sebagai
+  baris tersendiri di bawah daftar. `null` bila belum menang EnakCoin minggu itu
+  ("Main untuk masuk leaderboard").
+- `entries` kosong (`[]`, tidak pernah `null`) bila belum ada yang menang minggu itu.
+- Tampilkan rentang minggu dari `week_start`–`week_end`; jangan menghitung minggu
+  sendiri dari jam perangkat.
+- Leaderboard tidak berubah sendiri. Muat ulang setelah complete berhasil, atau saat
+  layar leaderboard dibuka.
+- `date` yang bukan `YYYY-MM-DD` atau `game_id` yang bukan UUID ditolak `304` (bug di
+  game; pesan umum).
+
+---
+
+## 11. Checklist
 
 - [ ] Game baru sudah didaftarkan bersama tim backoffice (§2.3); `slug` diperiksa saat `init` (§6.1).
 - [ ] Body complete sesuai jenis hadiah game (§2.2).
@@ -616,5 +659,6 @@ saja.
 - [ ] Complete hanya mengirim `score` / `outcome` / `data`, tidak pernah hadiah.
 - [ ] Hadiah di layar dari `reward_total`; `limited_by` dan `REFUNDED` ditangani.
 - [ ] Spin berhenti di `prize.entry`.
+- [ ] Leaderboard (§10): rentang minggu dari `week_start`/`week_end`, baris `is_me` sebagai "Kamu", `me` di luar `limit` tampil di bawah daftar, dimuat ulang setelah complete.
 - [ ] Complete diulang dengan aman saat gagal; timeout `expires_at` ditangani.
 - [ ] `balance_changed` dikirim setelah start dan complete; `close` saat keluar.

docs/rfc-enakgame.md

@@ -843,6 +843,7 @@ tambahkan snapshot harian, bukan cache yang di-invalidate.
 | `POST` | `/sessions/:id/complete` | §7.2. Idempotent tanpa header |
 | `GET` | `/sessions/:id` | Status dan hasil |
 | `GET` | `/sessions` | Riwayat main; filter opsional `game_id`, `status` (dipakai game untuk menemukan session `STARTED` setelah reload) |
+| `GET` | `/leaderboard` | Peringkat mingguan (Senin–Minggu, Asia/Jakarta) org customer menurut EnakCoin yang dimenangkan dari game. Query opsional `date` (hari mana pun dalam minggu itu), `game_id`, `limit` (default 10, maks 100) |
 
 Prefix `/enakgame` dipakai karena `/customer/games` sudah dipakai alur spin lama.
 
@@ -940,7 +941,8 @@ Ditemukan saat memetakan code. Tidak memblokir RFC ini, tapi sebagian berdampak
 ## 16. Di Luar Scope
 
 - **Mission** (PRD §3.1, §19). PRD belum mendefinisikan aturannya.
-- **Leaderboard** (PRD §15).
+- **Leaderboard event** (PRD §15). Leaderboard mingguan umum sudah ada (§11, ditambahkan
+  2026-10-12); leaderboard per event dengan aturannya sendiri belum.
 - **Reward `TIERED`** (§8).
 - **Budget Controller automatic mode** (D9).
 - **Hosting dan build Phaser.** RFC ini hanya mendefinisikan API yang dipanggil game.

internal/handler/enakgame_customer_handler.go

@@ -78,6 +78,20 @@ func (h *EnakGameCustomerHandler) GetSession(c *gin.Context) {
 	util.HandleResponse(c.Writer, c.Request, h.service.GetSession(c.Request.Context(), customerID, id), method)
 }
 
+// Leaderboard is GET /customer/enakgame/leaderboard?date=&game_id=&limit=.
+func (h *EnakGameCustomerHandler) Leaderboard(c *gin.Context) {
+	const method = "EnakGameCustomerHandler::Leaderboard"
+	customerID, ok := customerIDFromGin(c, method)
+	if !ok {
+		return
+	}
+	var q models.EnakGameLeaderboardQuery
+	if !bindQuery(c, &q, method) {
+		return
+	}
+	util.HandleResponse(c.Writer, c.Request, h.service.Leaderboard(c.Request.Context(), customerID, q), method)
+}
+
 // CompleteSession is POST /customer/enakgame/sessions/:id/complete. The body is read
 // leniently on purpose: a reward amount, or anything else the backend does not take
 // from the client, is ignored rather than refused (P1). An empty body is a result

internal/models/enakgame.go

@@ -199,6 +199,34 @@ type GameSessionListQuery struct {
 	Limit  int    `form:"limit"`
 }
 
+// EnakGameLeaderboardQuery picks a week of the leaderboard, and optionally one game.
+type EnakGameLeaderboardQuery struct {
+	// Any day of the week, YYYY-MM-DD in Asia/Jakarta; this week when empty.
+	Date   string `form:"date"`
+	GameID string `form:"game_id"`
+	Limit  int    `form:"limit"`
+}
+
+// EnakGameLeaderboard ranks the customers of an organization by the EnakCoin they won
+// from games in one week, Monday to Sunday in Asia/Jakarta.
+type EnakGameLeaderboard struct {
+	WeekStart string                     `json:"week_start"`
+	WeekEnd   string                     `json:"week_end"`
+	GameID    *uuid.UUID                 `json:"game_id"`
+	Entries   []EnakGameLeaderboardEntry `json:"entries"`
+	// The customer asking, wherever they rank; null when they won nothing that week.
+	Me *EnakGameLeaderboardEntry `json:"me"`
+}
+
+// EnakGameLeaderboardEntry is one customer on the leaderboard. Other customers are
+// shown by a masked name only.
+type EnakGameLeaderboardEntry struct {
+	Rank  int    `json:"rank"`
+	Name  string `json:"name"`
+	Coins int64  `json:"coins"`
+	IsMe  bool   `json:"is_me"`
+}
+
 // GameSessionCompleteInput is what the client reports at the end of a play (§7.2): data
 // only. Anything else it sends, a reward amount above all, is ignored (P1).
 type GameSessionCompleteInput struct {

internal/processor/game_leaderboard.go

@@ -0,0 +1,98 @@
+package processor
+
+import (
+	"context"
+	"strings"
+	"time"
+
+	"github.com/google/uuid"
+
+	"apskel-pos-be/internal/models"
+	"apskel-pos-be/internal/repository"
+)
+
+const (
+	// leaderboardLimit is how many ranks a leaderboard shows unless asked, and
+	// leaderboardMaxLimit the most it shows.
+	leaderboardLimit    = 10
+	leaderboardMaxLimit = 100
+)
+
+// Leaderboard ranks the customers of the customer's organization by the EnakCoin they
+// won from games in one week, Monday to Sunday in Asia/Jakarta: this week, or the one
+// holding q.Date. A session counts in the week it started. Refunded, expired and
+// flagged sessions count for nothing.
+func (p *GameSessionProcessor) Leaderboard(ctx context.Context, customerID uuid.UUID, q models.EnakGameLeaderboardQuery) (*models.EnakGameLeaderboard, error) {
+	day := walletDay(p.now())
+	if s := strings.TrimSpace(q.Date); s != "" {
+		d, err := time.ParseInLocation("2006-01-02", s, walletDisplayLocation)
+		if err != nil {
+			return nil, gameSessionRejected("date must be YYYY-MM-DD")
+		}
+		day = d
+	}
+	weekStart := leaderboardWeekStart(day)
+	filter := repository.LeaderboardFilter{
+		CustomerID: customerID, From: weekStart, To: weekStart.AddDate(0, 0, 7), Limit: q.Limit,
+	}
+	if filter.Limit < 1 || filter.Limit > leaderboardMaxLimit {
+		filter.Limit = leaderboardLimit
+	}
+	if s := strings.TrimSpace(q.GameID); s != "" {
+		id, err := uuid.Parse(s)
+		if err != nil {
+			return nil, gameSessionRejected("game_id must be a UUID")
+		}
+		filter.GameID = &id
+	}
+	customer, err := p.customers.GetCustomer(ctx, customerID)
+	if err != nil {
+		return nil, err
+	}
+	filter.OrganizationID = customer.OrganizationID
+	rows, err := p.sessions.Leaderboard(ctx, filter)
+	if err != nil {
+		return nil, err
+	}
+	board := &models.EnakGameLeaderboard{
+		WeekStart: weekStart.Format("2006-01-02"), WeekEnd: weekStart.AddDate(0, 0, 6).Format("2006-01-02"),
+		GameID: filter.GameID, Entries: []models.EnakGameLeaderboardEntry{},
+	}
+	for _, row := range rows {
+		entry := models.EnakGameLeaderboardEntry{
+			Rank: row.Rank, Name: maskCustomerName(row.Name), Coins: row.Coins, IsMe: row.CustomerID == customerID,
+		}
+		if row.Rank <= filter.Limit {
+			board.Entries = append(board.Entries, entry)
+		}
+		if entry.IsMe {
+			me := entry
+			board.Me = &me
+		}
+	}
+	return board, nil
+}
+
+// leaderboardWeekStart is the Monday, at midnight in Asia/Jakarta, of the week of day.
+func leaderboardWeekStart(day time.Time) time.Time {
+	day = walletDay(day)
+	return day.AddDate(0, 0, -((int(day.Weekday()) + 6) % 7))
+}
+
+// maskCustomerName keeps the first word of a name and the first letter of every other
+// word: "Budi Santoso" is shown as "Budi S******". A word with a digit, as when a phone
+// number was used for the name, keeps only its first character, the first word too.
+func maskCustomerName(name string) string {
+	words := strings.Fields(name)
+	if len(words) == 0 {
+		return "Pemain"
+	}
+	for i, w := range words {
+		if i == 0 && !strings.ContainsAny(w, "0123456789") {
+			continue
+		}
+		r := []rune(w)
+		words[i] = string(r[0]) + strings.Repeat("*", len(r)-1)
+	}
+	return strings.Join(words, " ")
+}

internal/processor/game_leaderboard_db_test.go

@@ -0,0 +1,95 @@
+package processor
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"apskel-pos-be/internal/models"
+)
+
+// The weekly leaderboard against Postgres. Needs TEST_DATABASE_URL; see
+// internal/repository/wallet_repository_test.go.
+func TestGameSession_Leaderboard(t *testing.T) {
+	e := newEnakGameEnv(t)
+	ctx := e.ctx()
+	dave := uuid.New()
+	require.NoError(t, e.db.Exec(`INSERT INTO customers (id, organization_id, name) VALUES (?, ?, 'Dave Lee')`, dave, e.orgA).Error)
+	runner := e.playableGame(e.orgA, "runner", 1)
+	other := e.playableGame(e.orgA, "other", 1)
+	theirs := e.playableGame(e.orgB, "theirs", 1)
+	for _, c := range []uuid.UUID{e.alice, e.bob, e.carol, dave} {
+		e.coins(c, 100, nil)
+	}
+	n := 0
+	// play completes a session of game for customer and returns its id; every
+	// playableGame pays 10.
+	play := func(customer, game uuid.UUID) uuid.UUID {
+		t.Helper()
+		n++
+		s, err := e.sessions.Start(ctx, customer, game, fmt.Sprintf("k%d", n))
+		require.NoError(t, err)
+		_, err = e.sessions.Complete(ctx, customer, s.SessionID, models.GameSessionCompleteInput{})
+		require.NoError(t, err)
+		return s.SessionID
+	}
+	play(e.alice, runner.ID)
+	play(e.alice, other.ID)
+	bobs := play(e.bob, runner.ID)
+	play(dave, runner.ID)
+	play(e.carol, theirs.ID)
+	// Bob reached 10 before Dave did.
+	require.NoError(t, e.db.Exec(`UPDATE game_sessions SET ended_at = ended_at - INTERVAL '1 minute' WHERE id = ?`, bobs).Error)
+	flagged := play(e.bob, runner.ID)
+	require.NoError(t, e.db.Exec(`UPDATE game_sessions SET flagged = TRUE WHERE id = ?`, flagged).Error)
+	lastWeek := play(dave, runner.ID)
+	require.NoError(t, e.db.Exec(`UPDATE game_sessions SET started_at = started_at - INTERVAL '7 days' WHERE id = ?`, lastWeek).Error)
+	_, err := e.sessions.Start(ctx, e.alice, runner.ID, "open")
+	require.NoError(t, err, "a STARTED session counts for nothing")
+
+	board, err := e.sessions.Leaderboard(ctx, e.bob, models.EnakGameLeaderboardQuery{})
+	require.NoError(t, err)
+	week := leaderboardWeekStart(e.now)
+	assert.Equal(t, week.Format("2006-01-02"), board.WeekStart)
+	assert.Equal(t, week.AddDate(0, 0, 6).Format("2006-01-02"), board.WeekEnd)
+	assert.Equal(t, []models.EnakGameLeaderboardEntry{
+		{Rank: 1, Name: "Alice", Coins: 20},
+		{Rank: 2, Name: "Bob", Coins: 10, IsMe: true},
+		{Rank: 3, Name: "Dave L**", Coins: 10},
+	}, board.Entries, "the flagged play, last week's play and another organization's do not count")
+	require.NotNil(t, board.Me)
+	assert.Equal(t, 2, board.Me.Rank)
+
+	board, err = e.sessions.Leaderboard(ctx, dave, models.EnakGameLeaderboardQuery{Limit: 1})
+	require.NoError(t, err)
+	require.Len(t, board.Entries, 1)
+	assert.Equal(t, "Alice", board.Entries[0].Name)
+	require.NotNil(t, board.Me, "the customer asking is returned below the limit")
+	assert.Equal(t, models.EnakGameLeaderboardEntry{Rank: 3, Name: "Dave L**", Coins: 10, IsMe: true}, *board.Me)
+
+	board, err = e.sessions.Leaderboard(ctx, e.alice, models.EnakGameLeaderboardQuery{GameID: other.ID.String()})
+	require.NoError(t, err)
+	assert.Equal(t, []models.EnakGameLeaderboardEntry{{Rank: 1, Name: "Alice", Coins: 10, IsMe: true}}, board.Entries)
+	assert.Equal(t, &other.ID, board.GameID)
+
+	board, err = e.sessions.Leaderboard(ctx, dave, models.EnakGameLeaderboardQuery{Date: week.AddDate(0, 0, -3).Format("2006-01-02")})
+	require.NoError(t, err)
+	assert.Equal(t, []models.EnakGameLeaderboardEntry{{Rank: 1, Name: "Dave L**", Coins: 10, IsMe: true}}, board.Entries, "last week")
+
+	board, err = e.sessions.Leaderboard(ctx, e.carol, models.EnakGameLeaderboardQuery{})
+	require.NoError(t, err)
+	assert.Equal(t, []models.EnakGameLeaderboardEntry{{Rank: 1, Name: "Carol", Coins: 10, IsMe: true}}, board.Entries, "only the customer's organization")
+
+	board, err = e.sessions.Leaderboard(ctx, e.bob, models.EnakGameLeaderboardQuery{GameID: uuid.NewString(), Date: "2020-01-01"})
+	require.NoError(t, err)
+	assert.Empty(t, board.Entries)
+	assert.Nil(t, board.Me)
+
+	_, err = e.sessions.Leaderboard(ctx, e.bob, models.EnakGameLeaderboardQuery{Date: "12-10-2026"})
+	assert.ErrorIs(t, err, ErrGameSessionRejected)
+	_, err = e.sessions.Leaderboard(ctx, e.bob, models.EnakGameLeaderboardQuery{GameID: "runner"})
+	assert.ErrorIs(t, err, ErrGameSessionRejected)
+}

internal/processor/game_leaderboard_test.go

@@ -0,0 +1,38 @@
+package processor
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMaskCustomerName(t *testing.T) {
+	for name, want := range map[string]string{
+		"Budi Santoso":        "Budi S******",
+		"budi":                "budi",
+		"  Siti   Nur Aisyah": "Siti N** A*****",
+		"Ádám Ő":              "Ádám Ő",
+		"081234567890":        "0***********",
+		"Budi2 Santoso":       "B**** S******",
+		"":                    "Pemain",
+		"   ":                 "Pemain",
+	} {
+		assert.Equal(t, want, maskCustomerName(name), "%q", name)
+	}
+}
+
+func TestLeaderboardWeekStart(t *testing.T) {
+	monday := time.Date(2026, 10, 12, 0, 0, 0, 0, walletDisplayLocation)
+	for _, day := range []time.Time{
+		monday,
+		time.Date(2026, 10, 14, 12, 0, 0, 0, walletDisplayLocation),
+		time.Date(2026, 10, 18, 23, 59, 59, 0, walletDisplayLocation),
+		// Sunday 17:00 UTC is already Monday 00:00 in Jakarta.
+		time.Date(2026, 10, 11, 17, 0, 0, 0, time.UTC),
+	} {
+		assert.True(t, monday.Equal(leaderboardWeekStart(day)), "%s", day)
+	}
+	// Sunday 16:59 UTC is still Sunday in Jakarta, the week before.
+	assert.True(t, monday.AddDate(0, 0, -7).Equal(leaderboardWeekStart(time.Date(2026, 10, 11, 16, 59, 0, 0, time.UTC))))
+}

internal/repository/game_session_repository.go

@@ -70,6 +70,32 @@ type GameSessionRepository interface {
 
 	CreateSessionRewards(ctx context.Context, rewards []entities.GameSessionReward) error
 	ListSessionRewards(ctx context.Context, sessionID uuid.UUID) ([]entities.GameSessionReward, error)
+
+	// Leaderboard ranks the active customers of an organization by the EnakCoin their
+	// completed, unflagged sessions started in [from, to) won, and returns the first
+	// limit ranks plus the row of filter.CustomerID wherever it ranks.
+	Leaderboard(ctx context.Context, filter LeaderboardFilter) ([]LeaderboardRow, error)
+}
+
+// LeaderboardFilter selects the sessions a leaderboard counts.
+type LeaderboardFilter struct {
+	OrganizationID uuid.UUID
+	// Nil for every game.
+	GameID *uuid.UUID
+	From   time.Time
+	To     time.Time
+	Limit  int
+	// The customer asking, returned even below Limit.
+	CustomerID uuid.UUID
+}
+
+// LeaderboardRow is one customer's total. Equal totals rank by who reached theirs
+// first, so no two rows share a rank.
+type LeaderboardRow struct {
+	Rank       int
+	CustomerID uuid.UUID
+	Name       string
+	Coins      int64
 }
 
 type gameSessionRepository struct {
@@ -255,3 +281,45 @@ func (r *gameSessionRepository) ListDueSessions(ctx context.Context, now time.Ti
 	}
 	return due, nil
 }
+
+func (r *gameSessionRepository) Leaderboard(ctx context.Context, filter LeaderboardFilter) ([]LeaderboardRow, error) {
+	gameFilter, args := "", []any{filter.OrganizationID, filter.From, filter.To, constants.GameSessionStatusCompleted}
+	if filter.GameID != nil {
+		gameFilter = "AND s.game_id = ?"
+		args = append(args, *filter.GameID)
+	}
+	args = append(args, filter.Limit, filter.CustomerID)
+	var rows []struct {
+		Rank       int
+		CustomerID string
+		Name       string
+		Coins      int64
+	}
+	err := DBFromContext(ctx, r.db).WithContext(ctx).Raw(`
+		WITH totals AS (
+			SELECT s.customer_id, SUM(s.reward_total) AS coins, MAX(s.ended_at) AS reached_at
+			FROM game_sessions s
+			WHERE s.organization_id = ? AND s.started_at >= ? AND s.started_at < ?
+				AND s.status = ? AND NOT s.flagged AND s.reward_total > 0 `+gameFilter+`
+			GROUP BY s.customer_id
+		), ranked AS (
+			SELECT t.customer_id, c.name, t.coins,
+				ROW_NUMBER() OVER (ORDER BY t.coins DESC, t.reached_at, t.customer_id) AS rank
+			FROM totals t
+			JOIN customers c ON c.id = t.customer_id AND c.is_active
+		)
+		SELECT rank, customer_id::text AS customer_id, name, coins
+		FROM ranked
+		WHERE rank <= ? OR customer_id = ?
+		ORDER BY rank`, args...).Scan(&rows).Error
+	if err != nil {
+		return nil, fmt.Errorf("failed to read game leaderboard: %w", err)
+	}
+	out := make([]LeaderboardRow, 0, len(rows))
+	for _, row := range rows {
+		l := LeaderboardRow{Rank: row.Rank, Name: row.Name, Coins: row.Coins}
+		l.CustomerID, _ = uuid.Parse(row.CustomerID)
+		out = append(out, l)
+	}
+	return out, nil
+}

internal/router/router.go

@@ -197,6 +197,7 @@ func (r *Router) addAppRoutes(rg *gin.Engine) {
 				enakGame.GET("/sessions", r.enakGameCustomerHandler.ListSessions)
 				enakGame.GET("/sessions/:id", r.enakGameCustomerHandler.GetSession)
 				enakGame.POST("/sessions/:id/complete", r.enakGameCustomerHandler.CompleteSession)
+				enakGame.GET("/leaderboard", r.enakGameCustomerHandler.Leaderboard)
 			}
 
 			// Vouchers: what EnakPoint is spent on, whatever it came from (docs/rfc-enakgame.md

internal/service/enakgame_service.go

@@ -74,6 +74,7 @@ type EnakGameCustomerService interface {
 	CompleteSession(ctx context.Context, customerID, sessionID uuid.UUID, in models.GameSessionCompleteInput) *contract.Response
 	ListSessions(ctx context.Context, customerID uuid.UUID, q models.GameSessionListQuery) *contract.Response
 	GetSession(ctx context.Context, customerID, sessionID uuid.UUID) *contract.Response
+	Leaderboard(ctx context.Context, customerID uuid.UUID, q models.EnakGameLeaderboardQuery) *contract.Response
 
 	ListVouchers(ctx context.Context, customerID uuid.UUID) *contract.Response
 	RedeemVoucher(ctx context.Context, customerID, voucherID uuid.UUID, req *contract.RedeemVoucherRequest, idempotencyKey string, info models.CustomerPinRequestInfo) *contract.Response
@@ -381,6 +382,11 @@ func (s *EnakGameCustomerServiceImpl) GetSession(ctx context.Context, customerID
 	return respond(ctx, session, err)
 }
 
+func (s *EnakGameCustomerServiceImpl) Leaderboard(ctx context.Context, customerID uuid.UUID, q models.EnakGameLeaderboardQuery) *contract.Response {
+	board, err := s.sessions.Leaderboard(ctx, customerID, q)
+	return respond(ctx, board, err)
+}
+
 // decodeStrict reads a JSON body into v, refusing unknown fields and trailing data.
 // It returns the error response, or nil when the body fits.
 func decodeStrict(body []byte, v any) *contract.Response {