feat(loyalty): give new balances their expiry

Every lot now gets its expiry when it is created (docs/prd-point-coin.md
F12, PC-502), where it used to never expire until note N4 was settled:

- EARN and an ADJUSTMENT that adds: ComputeExpiry of the organization's
  settings for that currency, from the moment received.
- EXCHANGE_IN: the sooner of the EnakCoin lot's expiry and when EnakPoint
  received now expire (F4).
- PAYMENT_REFUND: the expiry of the lot the EnakPoint came from, but at
  least seven days from the refund (N4, decided). A lot that never expired
  stays so.
- TRANSFER_IN: unchanged, exactly the sender's expiry.

Turning expiry on for a currency for the first time dates every lot of the
organization that still holds something and has no expiry, MIGRATION lots
included, in the same transaction as the setting: a full period from now
when ROLLING, the second fixed date on or after today when FIXED_DATE, so
no customer loses a balance soon after the rule is announced (N4,
decided). Turning it off leaves dated lots as they are. PUT
/marketing/loyalty-settings reports these as expiry_activations (currency,
lots, amount, expires_at); a dry run counts them without dating anything.

The earning processor now also reads the organization settings, and the
wallet admin processor takes the settings reader.

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

internal/app/app.go

@@ -480,7 +480,7 @@ func (a *App) initProcessors(cfg *config.Config, repos *repositories) *processor
 		walletTransferProcessor:             walletTransferProcessor,
 		walletTraceProcessor:                processor.NewWalletTraceProcessor(repository.NewWalletTraceRepository(a.db)),
 		customerDeviceProcessor:             customerDeviceProcessor,
-		walletAdminProcessor:                processor.NewWalletAdminProcessor(repository.NewWalletAdminRepository(a.db), repos.walletQueryRepo, processor.NewWalletProcessor(repos.walletRepo), repos.txManager),
+		walletAdminProcessor:                processor.NewWalletAdminProcessor(repository.NewWalletAdminRepository(a.db), repos.walletQueryRepo, processor.NewWalletProcessor(repos.walletRepo), loyaltySettingsProcessor, repos.txManager),
 	}
 }
 

internal/handler/loyalty_settings_db_test.go

@@ -113,7 +113,7 @@ func TestOutletLoyaltySettingsEndpoints_AgainstPostgres(t *testing.T) {
 	orgSettings, err := settings.Organization(context.Background(), org)
 	require.NoError(t, err)
 	orgSettings.PointValue = 5
-	_, err = settings.UpdateOrganization(context.Background(), org, admin, *orgSettings)
+	_, _, err = settings.UpdateOrganization(context.Background(), org, admin, *orgSettings)
 	require.NoError(t, err)
 	status, body = call(http.MethodGet, "/manager"+path, "")
 	require.Equal(t, http.StatusOK, status, body)

internal/handler/wallet_admin_db_test.go

@@ -74,7 +74,7 @@ func TestWalletAdminEndpoints_AgainstPostgres(t *testing.T) {
 	}))
 
 	h := NewWalletAdminHandler(
-		service.NewWalletAdminService(processor.NewWalletAdminProcessor(repository.NewWalletAdminRepository(db), queryRepo, wallet, txm), processor.NewWalletTraceProcessor(repository.NewWalletTraceRepository(db))),
+		service.NewWalletAdminService(processor.NewWalletAdminProcessor(repository.NewWalletAdminRepository(db), queryRepo, wallet, processor.NewLoyaltySettingsProcessor(repository.NewLoyaltySettingsRepository(db), txm), txm), processor.NewWalletTraceProcessor(repository.NewWalletTraceRepository(db))),
 		validator.NewWalletValidator(),
 	)
 	gin.SetMode(gin.TestMode)

internal/models/loyalty.go

@@ -125,12 +125,23 @@ type OrganizationLoyaltySettingsView struct {
 	Impact LoyaltySettingsImpact `json:"impact"`
 	// When a balance received now would expire under these settings (F12).
 	ExpiryPreview LoyaltyExpiryPreview `json:"expiry_preview"`
+	// The currencies this change turns expiry on for, and the balances affected.
+	ExpiryActivations []LoyaltyExpiryActivation `json:"expiry_activations"`
 	// On PUT, the keys that changed; on a dry run, the keys that would.
 	Changes []LoyaltySettingChange `json:"changes"`
 	// True when nothing was saved.
 	DryRun bool `json:"dry_run"`
 }
 
+// LoyaltyExpiryActivation is expiry being turned on for a currency: the balances that
+// had no expiry and the expiry they get (F12). On a dry run nothing is dated yet.
+type LoyaltyExpiryActivation struct {
+	Currency  string    `json:"currency"`
+	Lots      int64     `json:"lots"`
+	Amount    int64     `json:"amount"`
+	ExpiresAt time.Time `json:"expires_at"`
+}
+
 // LoyaltyExpiryPreview is what the dashboard shows next to the expiry settings: "the
 // EnakPoint received today expire on …". Nil means they never expire.
 type LoyaltyExpiryPreview struct {

internal/processor/earning_processor.go

@@ -36,17 +36,25 @@ type outletSettingsReader interface {
 	Outlet(ctx context.Context, outletID uuid.UUID) (*models.OutletLoyaltySettings, error)
 }
 
+// earningSettingsReader gives the outlet's earning settings and the organization's
+// expiry. LoyaltySettingsProcessor is one.
+type earningSettingsReader interface {
+	outletSettingsReader
+	organizationSettingsReader
+}
+
 // EarningProcessor credits EnakPoint and EnakCoin for paid orders
 // (docs/prd-point-coin.md F3).
 type EarningProcessor struct {
 	orders   repository.EarningRepository
-	settings outletSettingsReader
+	settings earningSettingsReader
+	now      func() time.Time
 	wallet   *WalletProcessor
 	tx       TxRunner
 }
 
-func NewEarningProcessor(orders repository.EarningRepository, settings outletSettingsReader, wallet *WalletProcessor, tx TxRunner) *EarningProcessor {
+func NewEarningProcessor(orders repository.EarningRepository, settings earningSettingsReader, wallet *WalletProcessor, tx TxRunner) *EarningProcessor {
-	return &EarningProcessor{orders: orders, settings: settings, wallet: wallet, tx: tx}
+	return &EarningProcessor{orders: orders, settings: settings, wallet: wallet, tx: tx, now: time.Now}
 }
 
 // OnOrderPaid is called once an order has become fully paid and the payment has
@@ -87,6 +95,12 @@ func (p *EarningProcessor) EarnForOrder(ctx context.Context, orderID uuid.UUID)
 		return &EarningOutcome{Skipped: EarningSkipNothingToEarn}, nil
 	}
 
+	orgSettings, err := p.settings.Organization(ctx, order.OrganizationID)
+	if err != nil {
+		return nil, err
+	}
+	receivedAt := p.now()
+
 	outcome := &EarningOutcome{}
 	err = p.tx.WithTransaction(ctx, func(ctx context.Context) error {
 		for _, c := range []struct {
@@ -101,19 +115,24 @@ func (p *EarningProcessor) EarnForOrder(ctx context.Context, orderID uuid.UUID)
 				continue
 			}
 			outletID := order.OutletID
-			res, err := p.wallet.Credit(ctx, WalletCreditInput{WalletEntry: WalletEntry{
+			res, err := p.wallet.Credit(ctx, WalletCreditInput{
-				CustomerID:     *order.CustomerID,
+				WalletEntry: WalletEntry{
-				Currency:       c.currency,
+					CustomerID:     *order.CustomerID,
-				Type:           constants.WalletTxTypeEarn,
+					Currency:       c.currency,
-				Amount:         c.line.Amount,
+					Type:           constants.WalletTxTypeEarn,
-				ReferenceType:  constants.WalletRefTypeOrder,
+					Amount:         c.line.Amount,
-				ReferenceID:    order.ID,
+					ReferenceType:  constants.WalletRefTypeOrder,
-				OutletID:       &outletID,
+					ReferenceID:    order.ID,
-				Description:    earningDescription(order),
+					OutletID:       &outletID,
-				Metadata:       result.Metadata(c.line),
+					Description:    earningDescription(order),
-				IdempotencyKey: fmt.Sprintf("earn:%s:%s", order.ID, c.currency),
+					Metadata:       result.Metadata(c.line),
-				// Lots never expire until the expiry model is decided (F12, note N4).
+					IdempotencyKey: fmt.Sprintf("earn:%s:%s", order.ID, c.currency),
-			}})
+				},
+				Lots: []WalletLotInput{{
+					Amount:    c.line.Amount,
+					ExpiresAt: ComputeExpiry(ExpirySettings(orgSettings, c.currency), receivedAt),
+				}},
+			})
 			if err != nil {
 				return fmt.Errorf("crediting %s: %w", c.currency, err)
 			}

internal/processor/earning_processor_db_test.go

@@ -22,7 +22,7 @@ import (
 // failingSettings fails for the outlet settings until healed, to stand in for the
 // database being unreachable right after a payment.
 type failingSettings struct {
-	real outletSettingsReader
+	real earningSettingsReader
 	mu   sync.Mutex
 	fail bool
 }
@@ -227,3 +227,7 @@ func TestEarningProcessor_AgainstPostgres(t *testing.T) {
 	assert.Equal(t, int64(875+250+600+400), balance.PointBalance)
 	assert.Equal(t, int64(3+1+2+1), balance.CoinBalance)
 }
+
+func (f *failingSettings) Organization(ctx context.Context, organizationID uuid.UUID) (*models.OrganizationLoyaltySettings, error) {
+	return f.real.Organization(ctx, organizationID)
+}

internal/processor/loyalty_settings_processor.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/google/uuid"
 
@@ -27,10 +28,11 @@ var ErrInvalidLoyaltySettings = errors.New("invalid loyalty settings")
 type LoyaltySettingsProcessor struct {
 	repo repository.LoyaltySettingsRepository
 	tx   TxRunner
+	now  func() time.Time
 }
 
 func NewLoyaltySettingsProcessor(repo repository.LoyaltySettingsRepository, tx TxRunner) *LoyaltySettingsProcessor {
-	return &LoyaltySettingsProcessor{repo: repo, tx: tx}
+	return &LoyaltySettingsProcessor{repo: repo, tx: tx, now: time.Now}
 }
 
 // Outlet returns an outlet's settings.
@@ -111,11 +113,15 @@ func (p *LoyaltySettingsProcessor) UpdateOutlet(ctx context.Context, organizatio
 }
 
 // UpdateOrganization replaces an organization's settings and returns what changed.
-func (p *LoyaltySettingsProcessor) UpdateOrganization(ctx context.Context, organizationID, changedBy uuid.UUID, settings models.OrganizationLoyaltySettings) ([]models.LoyaltySettingChange, error) {
+//
+// Turning expiry on for a currency for the first time also gives every existing lot
+// without an expiry the activation expiry (F12, note N4), and the result lists them.
+func (p *LoyaltySettingsProcessor) UpdateOrganization(ctx context.Context, organizationID, changedBy uuid.UUID, settings models.OrganizationLoyaltySettings) ([]models.LoyaltySettingChange, []models.LoyaltyExpiryActivation, error) {
 	if err := validateLoyaltyFields(organizationLoyaltyFields(&settings)); err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	var changes []models.LoyaltySettingChange
+	var activations []models.LoyaltyExpiryActivation
 	err := p.tx.WithTransaction(ctx, func(ctx context.Context) error {
 		if err := p.repo.LockScope(ctx, organizationID); err != nil {
 			return err
@@ -132,9 +138,42 @@ func (p *LoyaltySettingsProcessor) UpdateOrganization(ctx context.Context, organ
 			func(key string, value *string) error {
 				return p.repo.SetOrganizationValue(ctx, organizationID, key, value)
 			})
+		if err != nil {
+			return err
+		}
+		activations, err = p.expiryActivations(ctx, organizationID, current, settings, true)
 		return err
 	})
-	return changes, err
+	if err != nil {
+		return nil, nil, err
+	}
+	return changes, activations, nil
+}
+
+// expiryActivations lists the currencies whose expiry these settings turn on, with the
+// balances that have no expiry yet and the expiry they get: a full period from now
+// (note N4, decided). With apply, it dates those lots.
+func (p *LoyaltySettingsProcessor) expiryActivations(ctx context.Context, organizationID uuid.UUID, before, after models.OrganizationLoyaltySettings, apply bool) ([]models.LoyaltyExpiryActivation, error) {
+	activations := []models.LoyaltyExpiryActivation{}
+	for _, currency := range []string{constants.WalletCurrencyPoint, constants.WalletCurrencyCoin} {
+		was, will := ExpirySettings(&before, currency), ExpirySettings(&after, currency)
+		if was.Enabled || !will.Enabled {
+			continue
+		}
+		expiresAt := *ActivationExpiry(will, p.now())
+		var lots, amount int64
+		var err error
+		if apply {
+			lots, amount, err = p.repo.DateUndatedLots(ctx, organizationID, currency, expiresAt)
+		} else {
+			lots, amount, err = p.repo.UndatedBalance(ctx, organizationID, currency)
+		}
+		if err != nil {
+			return nil, err
+		}
+		activations = append(activations, models.LoyaltyExpiryActivation{Currency: currency, Lots: lots, Amount: amount, ExpiresAt: expiresAt})
+	}
+	return activations, nil
 }
 
 // apply stores every field whose effective value changes and records it. A key left
@@ -466,14 +505,15 @@ func diffLoyaltyFields(organizationID uuid.UUID, outletID *uuid.UUID, changedBy
 }
 
 // PreviewOrganization validates new organization settings and lists what saving them
-// would change, without writing anything.
+// would change, and which balances turning expiry on would date, without writing
-func (p *LoyaltySettingsProcessor) PreviewOrganization(ctx context.Context, organizationID uuid.UUID, settings models.OrganizationLoyaltySettings) ([]models.LoyaltySettingChange, error) {
+// anything.
+func (p *LoyaltySettingsProcessor) PreviewOrganization(ctx context.Context, organizationID uuid.UUID, settings models.OrganizationLoyaltySettings) ([]models.LoyaltySettingChange, []models.LoyaltyExpiryActivation, error) {
 	if err := validateLoyaltyFields(organizationLoyaltyFields(&settings)); err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	raw, err := p.repo.GetOrganizationValues(ctx, organizationID)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	var current models.OrganizationLoyaltySettings
 	loadLoyaltyFields(organizationLoyaltyFields(&current), raw, "organization "+organizationID.String())
@@ -482,5 +522,9 @@ func (p *LoyaltySettingsProcessor) PreviewOrganization(ctx context.Context, orga
 	for _, row := range rows {
 		changes = append(changes, loyaltySettingChangeModel(row))
 	}
-	return changes, nil
+	activations, err := p.expiryActivations(ctx, organizationID, current, settings, false)
+	if err != nil {
+		return nil, nil, err
+	}
+	return changes, activations, nil
 }

internal/processor/loyalty_settings_processor_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"os"
 	"testing"
+	"time"
 
 	"github.com/google/uuid"
 	"github.com/stretchr/testify/assert"
@@ -29,6 +30,9 @@ type loyaltyRepoFake struct {
 	orgValues    map[string]string
 	changes      []entities.LoyaltySettingChange
 	locks        []uuid.UUID
+	// Lots without an expiry per currency: how many and what they hold.
+	undated map[string][2]int64
+	dated   map[string]time.Time
 }
 
 func (f *loyaltyRepoFake) GetOutletValues(context.Context, uuid.UUID) (map[string]string, error) {
@@ -263,7 +267,7 @@ func TestLoyaltySettings_UpdateOrganization(t *testing.T) {
 	settings.CoinExpiry.Enabled = true
 	settings.CoinExpiry.Unit = constants.LoyaltyExpiryUnitDay
 
-	changes, err := p.UpdateOrganization(ctx, org, admin, *settings)
+	changes, _, err := p.UpdateOrganization(ctx, org, admin, *settings)
 	require.NoError(t, err)
 	keys := []string{}
 	for _, c := range changes {
@@ -316,7 +320,7 @@ func TestLoyaltySettings_UpdateRejectsInvalidValues(t *testing.T) {
 		s, err := p.Organization(ctx, org)
 		require.NoError(t, err)
 		mutate(s)
-		_, err = p.UpdateOrganization(ctx, org, uuid.New(), *s)
+		_, _, err = p.UpdateOrganization(ctx, org, uuid.New(), *s)
 		assert.ErrorIs(t, err, ErrInvalidLoyaltySettings, name)
 	}
 	assert.Empty(t, repo.changes, "nothing is written when a value is invalid")
@@ -330,3 +334,52 @@ func TestLoyaltySettings_UpdateRejectsInvalidValues(t *testing.T) {
 	_, err = p.UpdateOutlet(ctx, org, uuid.New(), uuid.New(), *s)
 	assert.ErrorIs(t, err, repository.ErrLoyaltyOutletNotFound)
 }
+
+func (f *loyaltyRepoFake) UndatedBalance(_ context.Context, _ uuid.UUID, currency string) (int64, int64, error) {
+	u := f.undated[currency]
+	return u[0], u[1], nil
+}
+
+func (f *loyaltyRepoFake) DateUndatedLots(_ context.Context, _ uuid.UUID, currency string, expiresAt time.Time) (int64, int64, error) {
+	u := f.undated[currency]
+	if f.dated == nil {
+		f.dated = map[string]time.Time{}
+	}
+	f.dated[currency] = expiresAt
+	delete(f.undated, currency)
+	return u[0], u[1], nil
+}
+
+// Turning expiry on dates the balances that had none, a full cycle away; a dry run
+// only counts them, and saving again dates nothing more.
+func TestLoyaltySettings_TurningExpiryOnDatesExistingBalances(t *testing.T) {
+	org, admin := uuid.New(), uuid.New()
+	repo := &loyaltyRepoFake{undated: map[string][2]int64{"POINT": {3, 1500}, "COIN": {2, 40}}}
+	p := NewLoyaltySettingsProcessor(repo, txRunnerFake{})
+	p.now = func() time.Time { return time.Date(2026, 11, 20, 3, 0, 0, 0, time.UTC) }
+	ctx := context.Background()
+
+	settings, err := p.Organization(ctx, org)
+	require.NoError(t, err)
+	settings.PointExpiry.Enabled = true
+
+	_, preview, err := p.PreviewOrganization(ctx, org, *settings)
+	require.NoError(t, err)
+	require.Len(t, preview, 1)
+	assert.Equal(t, "POINT", preview[0].Currency)
+	assert.Equal(t, int64(1500), preview[0].Amount)
+	assert.Empty(t, repo.dated, "a dry run dates nothing")
+
+	_, activations, err := p.UpdateOrganization(ctx, org, admin, *settings)
+	require.NoError(t, err)
+	require.Len(t, activations, 1)
+	assert.Equal(t, int64(3), activations[0].Lots)
+	// Default FIXED_DATE on 31 Dec: the second one after 20 Nov 2026.
+	assert.Equal(t, "2027-12-31", activations[0].ExpiresAt.In(walletDisplayLocation).Format("2006-01-02"))
+	assert.Equal(t, activations[0].ExpiresAt, repo.dated["POINT"])
+	assert.NotContains(t, repo.dated, "COIN", "EnakCoin expiry stays off")
+
+	_, again, err := p.UpdateOrganization(ctx, org, admin, *settings)
+	require.NoError(t, err)
+	assert.Empty(t, again, "already on: nothing is activated twice")
+}

internal/processor/point_payment_refund.go

@@ -21,8 +21,8 @@ import (
 //
 // Never more than the payment used, and only what has not come back yet, so it can be
 // called again safely. Returned EnakPoint go back into lots with the expiry of the lots
-// they were taken from (the 7-day extension waits on note N4). It returns how many came
+// they were taken from, but at least seven days from the refund (note N4, decided). It
-// back in total.
+// returns how many came back in total.
 func (p *PointPaymentProcessor) RefundForOrder(ctx context.Context, orderID uuid.UUID) (int64, error) {
 	order, err := p.repo.GetOrder(ctx, orderID, false)
 	if err != nil {
@@ -78,7 +78,7 @@ func (p *PointPaymentProcessor) RefundForOrder(ctx context.Context, orderID uuid
 				take := min(room, left)
 				left -= take
 				lotID := a.LotID
-				lots = append(lots, WalletLotInput{Amount: take, ExpiresAt: a.ExpiresAt, OriginLotID: &lotID})
+				lots = append(lots, WalletLotInput{Amount: take, ExpiresAt: RefundExpiry(a.ExpiresAt, p.now()), OriginLotID: &lotID})
 			}
 			toReturn -= left
 

internal/processor/point_refund_db_test.go

@@ -92,7 +92,7 @@ func TestPointRefund_UsesTheFrozenValue(t *testing.T) {
 		s, err := settings.Organization(context.Background(), e.org)
 		require.NoError(t, err)
 		s.PointValue = v
-		_, err = settings.UpdateOrganization(context.Background(), e.org, e.cashier, *s)
+		_, _, err = settings.UpdateOrganization(context.Background(), e.org, e.cashier, *s)
 		require.NoError(t, err)
 	}
 	setValue(100)

internal/processor/wallet_admin_processor.go

@@ -21,15 +21,16 @@ const walletDescriptionLimit = 255
 // WalletAdminProcessor serves the dashboard's view of one customer's wallet and the
 // manual adjustments an admin makes to it (docs/prd-point-coin.md F7).
 type WalletAdminProcessor struct {
-	admin  repository.WalletAdminRepository
+	admin    repository.WalletAdminRepository
-	query  repository.WalletQueryRepository
+	query    repository.WalletQueryRepository
-	wallet *WalletProcessor
+	wallet   *WalletProcessor
-	tx     TxRunner
+	settings organizationSettingsReader
-	now    func() time.Time
+	tx       TxRunner
+	now      func() time.Time
 }
 
-func NewWalletAdminProcessor(admin repository.WalletAdminRepository, query repository.WalletQueryRepository, wallet *WalletProcessor, tx TxRunner) *WalletAdminProcessor {
+func NewWalletAdminProcessor(admin repository.WalletAdminRepository, query repository.WalletQueryRepository, wallet *WalletProcessor, settings organizationSettingsReader, tx TxRunner) *WalletAdminProcessor {
-	return &WalletAdminProcessor{admin: admin, query: query, wallet: wallet, tx: tx, now: time.Now}
+	return &WalletAdminProcessor{admin: admin, query: query, wallet: wallet, settings: settings, tx: tx, now: time.Now}
 }
 
 // GetCustomerWallet returns the customer's balances, lots and a page of history.
@@ -126,13 +127,20 @@ func (p *WalletAdminProcessor) Adjust(ctx context.Context, organizationID, admin
 		if _, err := p.admin.GetCustomer(ctx, organizationID, customerID); err != nil {
 			return err
 		}
-		var err error
+		if in.Amount < 0 {
-		if in.Amount > 0 {
+			var err error
-			// Adjustments never expire until expiry is decided (F12, note N4).
-			res, err = p.wallet.Credit(ctx, WalletCreditInput{WalletEntry: entry})
-		} else {
 			res, err = p.wallet.Debit(ctx, WalletDebitInput{WalletEntry: entry})
+			return err
 		}
+		// An adjustment that adds is a new balance, and expires like one (F7, F12).
+		settings, err := p.settings.Organization(ctx, organizationID)
+		if err != nil {
+			return err
+		}
+		res, err = p.wallet.Credit(ctx, WalletCreditInput{
+			WalletEntry: entry,
+			Lots:        []WalletLotInput{{Amount: entry.Amount, ExpiresAt: ComputeExpiry(ExpirySettings(settings, in.Currency), p.now())}},
+		})
 		return err
 	})
 	if err != nil {

internal/processor/wallet_exchange_processor.go

@@ -169,7 +169,7 @@ func (p *WalletExchangeProcessor) Exchange(ctx context.Context, customerID uuid.
 				Metadata:       metadata,
 				IdempotencyKey: inKey,
 			},
-			Lots: exchangeLots(out.Allocations, rate),
+			Lots: exchangeLots(out.Allocations, rate, ComputeExpiry(settings.PointExpiry, p.now())),
 		})
 		if err != nil {
 			return err
@@ -225,10 +225,9 @@ func exchangePoints(coins int64, rate models.LoyaltyExchangeSettings) int64 {
 // and after it, which adds up exactly because the total is a multiple of
 // coin_amount. A lot too small to earn a whole EnakPoint on its own gives none.
 //
-// F4 caps the expiry at now + the EnakPoint validity as well. EnakPoint have no
+// Each part expires at the sooner of its EnakCoin lot's expiry and pointExpiry, when an
-// validity until the expiry model is decided (F12, note N4), so for now the EnakCoin
+// EnakPoint received now would expire (F4); nil means never.
-// lot's expiry is the only bound.
+func exchangeLots(allocations []WalletAllocation, rate models.LoyaltyExchangeSettings, pointExpiry *time.Time) []WalletLotInput {
-func exchangeLots(allocations []WalletAllocation, rate models.LoyaltyExchangeSettings) []WalletLotInput {
 	var lots []WalletLotInput
 	var coinsSoFar int64
 	for _, a := range allocations {
@@ -239,7 +238,7 @@ func exchangeLots(allocations []WalletAllocation, rate models.LoyaltyExchangeSet
 			continue
 		}
 		lotID := a.LotID
-		lots = append(lots, WalletLotInput{Amount: points, ExpiresAt: a.ExpiresAt, OriginLotID: &lotID})
+		lots = append(lots, WalletLotInput{Amount: points, ExpiresAt: EarlierExpiry(a.ExpiresAt, pointExpiry), OriginLotID: &lotID})
 	}
 	return lots
 }

internal/processor/wallet_exchange_processor_test.go

@@ -332,3 +332,23 @@ func TestWalletExchange_RequiresAnIdempotencyKey(t *testing.T) {
 	assert.ErrorIs(t, err, ErrWalletMoveRejected)
 	assert.Empty(t, e.pins.actions)
 }
+
+// F4: EnakPoint from an exchange expire at the sooner of the EnakCoin lot's expiry and
+// when EnakPoint received now would expire.
+func TestWalletExchange_CappedByThePointExpiry(t *testing.T) {
+	e := newWalletMoveEnv(t)
+	e.now = wib(2026, 6, 1, 10, 0)
+	e.settings.PointExpiry = rolling(30, "DAY", false)
+	c := e.member("Budi", "081234561234")
+	soon, later := e.at(24*time.Hour), e.at(90*24*time.Hour)
+	e.earnCoins(t, c, 10, soon)
+	e.earnCoins(t, c, 10, later)
+	e.earnCoins(t, c, 10, nil)
+
+	res, err := e.exchanges().Exchange(e.ctx, c, 30, "482913", "key-1", models.CustomerPinRequestInfo{})
+	require.NoError(t, err)
+	require.Len(t, res.Lots, 3)
+	assert.Equal(t, soon, res.Lots[0].ExpiresAt, "the EnakCoin lot expires first")
+	assert.Equal(t, "2026-07-01", expiryDay(t, res.Lots[1].ExpiresAt), "30 days of EnakPoint come first")
+	assert.Equal(t, "2026-07-01", expiryDay(t, res.Lots[2].ExpiresAt), "a lot that never expired gets the EnakPoint expiry")
+}

internal/repository/loyalty_settings_repository.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"time"
 
 	"github.com/google/uuid"
 	"gorm.io/gorm"
@@ -47,6 +48,12 @@ type LoyaltySettingsRepository interface {
 	InsertChanges(ctx context.Context, changes []entities.LoyaltySettingChange) error
 	// ListChanges returns a page of history, newest first, and the total count.
 	ListChanges(ctx context.Context, filter LoyaltySettingChangeFilter) ([]entities.LoyaltySettingChange, int64, error)
+
+	// UndatedBalance counts an organization's lots of one currency that still hold
+	// something and have no expiry, and what they hold.
+	UndatedBalance(ctx context.Context, organizationID uuid.UUID, currency string) (lots, amount int64, err error)
+	// DateUndatedLots gives those lots an expiry, when expiry is turned on (F12).
+	DateUndatedLots(ctx context.Context, organizationID uuid.UUID, currency string, expiresAt time.Time) (lots, amount int64, err error)
 }
 
 type loyaltySettingsRepository struct {
@@ -174,3 +181,39 @@ func (r *loyaltySettingsRepository) ListChanges(ctx context.Context, filter Loya
 	}
 	return changes, total, nil
 }
+
+func (r *loyaltySettingsRepository) UndatedBalance(ctx context.Context, organizationID uuid.UUID, currency string) (int64, int64, error) {
+	var row struct{ Lots, Amount int64 }
+	err := DBFromContext(ctx, r.db).WithContext(ctx).Raw(`
+		SELECT COUNT(*) AS lots, COALESCE(SUM(remaining_amount), 0) AS amount
+		FROM wallet_lots
+		WHERE organization_id = ? AND currency = ? AND expires_at IS NULL AND remaining_amount > 0`,
+		organizationID, currency).Scan(&row).Error
+	if err != nil {
+		return 0, 0, fmt.Errorf("failed to sum undated wallet lots: %w", err)
+	}
+	return row.Lots, row.Amount, nil
+}
+
+func (r *loyaltySettingsRepository) DateUndatedLots(ctx context.Context, organizationID uuid.UUID, currency string, expiresAt time.Time) (int64, int64, error) {
+	db, err := r.requireTx(ctx)
+	if err != nil {
+		return 0, 0, err
+	}
+	var rows []struct{ RemainingAmount int64 }
+	// Only lots that still hold something: an empty lot never expires anything, and
+	// leaving it undated keeps the history as it was.
+	err = db.Raw(`
+		UPDATE wallet_lots SET expires_at = ?
+		WHERE organization_id = ? AND currency = ? AND expires_at IS NULL AND remaining_amount > 0
+		RETURNING remaining_amount`,
+		expiresAt, organizationID, currency).Scan(&rows).Error
+	if err != nil {
+		return 0, 0, fmt.Errorf("failed to date wallet lots: %w", err)
+	}
+	var amount int64
+	for _, row := range rows {
+		amount += row.RemainingAmount
+	}
+	return int64(len(rows)), amount, nil
+}

internal/repository/loyalty_settings_repository_test.go

@@ -124,7 +124,7 @@ func TestLoyaltySettings_AgainstPostgres(t *testing.T) {
 	orgSettings.PointValue = 200
 	saved := make(chan error, 1)
 	go func() {
-		_, err := p.UpdateOrganization(ctx, org, admin, *orgSettings)
+		_, _, err := p.UpdateOrganization(ctx, org, admin, *orgSettings)
 		saved <- err
 	}()
 	select {

internal/service/loyalty_settings_service.go

@@ -134,7 +134,7 @@ func (s *LoyaltySettingsServiceImpl) GetOrganizationSettings(ctx context.Context
 	if err != nil {
 		return loyaltyErrorResponse(err)
 	}
-	view, err := s.organizationView(ctx, apctx.OrganizationID, *current, *current, nil, false)
+	view, err := s.organizationView(ctx, apctx.OrganizationID, *current, *current, nil, nil, false)
 	if err != nil {
 		return loyaltyErrorResponse(err)
 	}
@@ -145,10 +145,11 @@ func (s *LoyaltySettingsServiceImpl) GetOrganizationSettings(ctx context.Context
 // of the GET response, which are ignored.
 type organizationSettingsInput struct {
 	*models.OrganizationLoyaltySettings
-	Impact        json.RawMessage `json:"impact"`
+	Impact            json.RawMessage `json:"impact"`
-	ExpiryPreview json.RawMessage `json:"expiry_preview"`
+	ExpiryPreview     json.RawMessage `json:"expiry_preview"`
-	Changes       json.RawMessage `json:"changes"`
+	ExpiryActivations json.RawMessage `json:"expiry_activations"`
-	DryRun        json.RawMessage `json:"dry_run"`
+	Changes           json.RawMessage `json:"changes"`
+	DryRun            json.RawMessage `json:"dry_run"`
 }
 
 func (s *LoyaltySettingsServiceImpl) UpdateOrganizationSettings(ctx context.Context, apctx *appcontext.ContextInfo, body []byte, dryRun bool) *contract.Response {
@@ -166,10 +167,11 @@ func (s *LoyaltySettingsServiceImpl) UpdateOrganizationSettings(ctx context.Cont
 	}
 
 	var changes []models.LoyaltySettingChange
+	var activations []models.LoyaltyExpiryActivation
 	if dryRun {
-		changes, err = s.settings.PreviewOrganization(ctx, apctx.OrganizationID, next)
+		changes, activations, err = s.settings.PreviewOrganization(ctx, apctx.OrganizationID, next)
 	} else {
-		changes, err = s.settings.UpdateOrganization(ctx, apctx.OrganizationID, apctx.UserID, next)
+		changes, activations, err = s.settings.UpdateOrganization(ctx, apctx.OrganizationID, apctx.UserID, next)
 	}
 	if err != nil {
 		return loyaltyErrorResponse(err)
@@ -182,7 +184,7 @@ func (s *LoyaltySettingsServiceImpl) UpdateOrganizationSettings(ctx context.Cont
 		}
 		after = *saved
 	}
-	view, err := s.organizationView(ctx, apctx.OrganizationID, *current, after, changes, dryRun)
+	view, err := s.organizationView(ctx, apctx.OrganizationID, *current, after, changes, activations, dryRun)
 	if err != nil {
 		return loyaltyErrorResponse(err)
 	}
@@ -197,12 +199,15 @@ func (s *LoyaltySettingsServiceImpl) ListHistory(ctx context.Context, apctx *app
 	return contract.BuildSuccessResponse(history)
 }
 
-func (s *LoyaltySettingsServiceImpl) organizationView(ctx context.Context, organizationID uuid.UUID, before, after models.OrganizationLoyaltySettings, changes []models.LoyaltySettingChange, dryRun bool) (*models.OrganizationLoyaltySettingsView, error) {
+func (s *LoyaltySettingsServiceImpl) organizationView(ctx context.Context, organizationID uuid.UUID, before, after models.OrganizationLoyaltySettings, changes []models.LoyaltySettingChange, activations []models.LoyaltyExpiryActivation, dryRun bool) (*models.OrganizationLoyaltySettingsView, error) {
 	now := time.Now()
 	points, coins, err := s.outstanding.OrganizationOutstanding(ctx, organizationID)
 	if err != nil {
 		return nil, err
 	}
+	if activations == nil {
+		activations = []models.LoyaltyExpiryActivation{}
+	}
 	if changes == nil {
 		changes = []models.LoyaltySettingChange{}
 	}