internal/app/app.go

@@ -414,7 +414,7 @@ func (a *App) initProcessors(cfg *config.Config, repos *repositories) *processor
 		productVariantProcessor:             processor.NewProductVariantProcessorImpl(repos.productVariantRepo, repos.productRepo),
 		inventoryProcessor:                  processor.NewInventoryProcessorImpl(repos.inventoryRepo, repos.productRepo, repos.outletRepo, repos.ingredientRepo, repos.inventoryMovementRepo),
 		orderProcessor:                      orderProcessor,
-		paymentMethodProcessor:              processor.NewPaymentMethodProcessorImpl(repos.paymentMethodRepo),
+		paymentMethodProcessor:              processor.NewPaymentMethodProcessorImpl(repos.paymentMethodRepo, loyaltySettingsProcessor),
 		fileProcessor:                       processor.NewFileProcessorImpl(repos.fileRepo, fileClient),
 		customerProcessor:                   processor.NewCustomerProcessor(repos.customerRepo),
 		analyticsProcessor:                  processor.NewAnalyticsProcessorImpl(repos.analyticsRepo, repos.expenseRepo),

internal/contract/payment_method_contract.go

@@ -18,7 +18,7 @@ type CreatePaymentMethodRequest struct {
 
 type UpdatePaymentMethodRequest struct {
 	Name          *string                `json:"name,omitempty" validate:"omitempty,min=1,max=100"`
-	Type          *string                `json:"type,omitempty" validate:"omitempty,oneof=cash card digital_wallet qr edc"`
+	Type          *string                `json:"type,omitempty" validate:"omitempty,oneof=cash card digital_wallet qr edc point"`
 	Processor     *string                `json:"processor,omitempty" validate:"omitempty,max=100"`
 	Configuration map[string]interface{} `json:"configuration,omitempty"`
 	IsActive      *bool                  `json:"is_active,omitempty"`
@@ -38,7 +38,9 @@ type PaymentMethodResponse struct {
 
 type ListPaymentMethodsRequest struct {
 	OrganizationID *uuid.UUID `json:"organization_id,omitempty"`
-	Type           *string    `json:"type,omitempty" validate:"omitempty,oneof=cash card digital_wallet qr edc"`
+	// When set, EnakPoint is left out unless the outlet accepts it (F9).
+	OutletID *uuid.UUID `json:"outlet_id,omitempty"`
+	Type     *string    `json:"type,omitempty" validate:"omitempty,oneof=cash card digital_wallet qr edc point"`
 	IsActive *bool      `json:"is_active,omitempty"`
 	Search   string     `json:"search,omitempty"`
 	Page     int        `json:"page" validate:"min=1"`

internal/entities/payment.go

@@ -13,13 +13,16 @@ const (
 	PaymentMethodTypeCash          PaymentMethodType = "cash"
 	PaymentMethodTypeCard          PaymentMethodType = "card"
 	PaymentMethodTypeDigitalWallet PaymentMethodType = "digital_wallet"
+	// The system method for paying with EnakPoint (docs/prd-point-coin.md F9). One per
+	// organization; it cannot be created, deleted or retyped through the API.
+	PaymentMethodTypePoint PaymentMethodType = "point"
 )
 
 type PaymentMethod struct {
 	ID             uuid.UUID         `gorm:"type:uuid;primary_key;default:gen_random_uuid()" json:"id"`
 	OrganizationID uuid.UUID         `gorm:"type:uuid;not null;index" json:"organization_id" validate:"required"`
 	Name           string            `gorm:"not null;size:100" json:"name" validate:"required,min=1,max=100"`
-	Type           PaymentMethodType `gorm:"not null;size:50" json:"type" validate:"required,oneof=cash card digital_wallet"`
+	Type           PaymentMethodType `gorm:"not null;size:50" json:"type" validate:"required,oneof=cash card digital_wallet point"`
 	Processor      *string           `gorm:"size:100" json:"processor"`
 	Configuration  Metadata          `gorm:"type:jsonb;default:'{}'" json:"configuration"`
 	IsActive       bool              `gorm:"default:true" json:"is_active"`
@@ -69,6 +72,10 @@ type Payment struct {
 	SplitType        *SplitType               `gorm:"size:20" json:"split_type,omitempty"`
 	SplitDescription *string                  `gorm:"size:255" json:"split_description,omitempty"`
 	RefundAmount     float64                  `gorm:"type:decimal(10,2);default:0.00" json:"refund_amount"`
+	// Set only for a payment with EnakPoint: how many were used, and the rupiah value of
+	// one then, frozen so a refund returns exactly what was used.
+	PointsUsed   *int64     `json:"points_used,omitempty"`
+	PointValue   *float64   `gorm:"type:decimal(10,2)" json:"point_value,omitempty"`
 	RefundReason *string    `gorm:"size:255" json:"refund_reason,omitempty"`
 	RefundedAt   *time.Time `gorm:"" json:"refunded_at,omitempty"`
 	RefundedBy   *uuid.UUID `gorm:"type:uuid" json:"refunded_by,omitempty"`

internal/handler/payment_method_handler.go

@@ -113,6 +113,16 @@ func (h *PaymentMethodHandler) ListPaymentMethods(c *gin.Context) {
 
 	req.OrganizationID = &contextInfo.OrganizationID
 
+	// At the cashier, EnakPoint is listed only where the outlet accepts it (F9).
+	if outletStr := c.Query("outlet_id"); outletStr != "" {
+		if outletID, err := uuid.Parse(outletStr); err == nil {
+			req.OutletID = &outletID
+		}
+	} else if contextInfo.OutletID != uuid.Nil {
+		outletID := contextInfo.OutletID
+		req.OutletID = &outletID
+	}
+
 	if isActiveStr := c.Query("is_active"); isActiveStr != "" {
 		if isActive, err := strconv.ParseBool(isActiveStr); err == nil {
 			req.IsActive = &isActive

internal/mappers/payment_method_mapper.go

@@ -134,6 +134,7 @@ func ListPaymentMethodsContractToModel(req *contract.ListPaymentMethodsRequest)
 
 	return &models.ListPaymentMethodsRequest{
 		OrganizationID: req.OrganizationID,
+		OutletID:       req.OutletID,
 		Type:           paymentMethodType,
 		IsActive:       req.IsActive,
 		Search:         req.Search,

internal/models/payment_method.go

@@ -51,6 +51,8 @@ type PaymentMethodResponse struct {
 
 type ListPaymentMethodsRequest struct {
 	OrganizationID *uuid.UUID
+	// When set, EnakPoint is left out unless the outlet accepts it (F9).
+	OutletID *uuid.UUID
 	Type     *constants.PaymentMethodType
 	IsActive *bool
 	Search   string

internal/processor/payment_method_processor.go

@@ -1,7 +1,10 @@
 package processor
 
 import (
+	"apskel-pos-be/internal/constants"
+	"apskel-pos-be/internal/entities"
 	"context"
+	"errors"
 	"fmt"
 
 	"apskel-pos-be/internal/mappers"
@@ -20,17 +23,26 @@ type PaymentMethodProcessor interface {
 	GetActivePaymentMethodsByOrganization(ctx context.Context, organizationID uuid.UUID) ([]models.PaymentMethodResponse, error)
 }
 
+// ErrSystemPaymentMethod means an attempt to create, delete or retype the EnakPoint
+// method, which the system owns (docs/prd-point-coin.md F9).
+var ErrSystemPaymentMethod = errors.New("the EnakPoint payment method is managed by the system: it cannot be created, deleted or change type")
+
 type PaymentMethodProcessorImpl struct {
 	paymentMethodRepo repository.PaymentMethodRepository
+	outletSettings    outletSettingsReader
 }
 
-func NewPaymentMethodProcessorImpl(paymentMethodRepo repository.PaymentMethodRepository) *PaymentMethodProcessorImpl {
+func NewPaymentMethodProcessorImpl(paymentMethodRepo repository.PaymentMethodRepository, outletSettings outletSettingsReader) *PaymentMethodProcessorImpl {
 	return &PaymentMethodProcessorImpl{
 		paymentMethodRepo: paymentMethodRepo,
+		outletSettings:    outletSettings,
 	}
 }
 
 func (p *PaymentMethodProcessorImpl) CreatePaymentMethod(ctx context.Context, req *models.CreatePaymentMethodRequest) (*models.PaymentMethodResponse, error) {
+	if req.Type == constants.PaymentMethodTypePoint {
+		return nil, ErrSystemPaymentMethod
+	}
 	exists, err := p.paymentMethodRepo.ExistsByName(ctx, req.OrganizationID, req.Name, nil)
 	if err != nil {
 		return nil, fmt.Errorf("failed to check payment method name uniqueness: %w", err)
@@ -77,6 +89,17 @@ func (p *PaymentMethodProcessorImpl) ListPaymentMethods(ctx context.Context, req
 	if req.Search != "" {
 		filters["search"] = req.Search
 	}
+	// At the cashier EnakPoint only shows where the outlet accepts it (F9). Filtered in
+	// the query so paging stays right.
+	if req.OutletID != nil && p.outletSettings != nil {
+		settings, err := p.outletSettings.Outlet(ctx, *req.OutletID)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read outlet loyalty settings: %w", err)
+		}
+		if !settings.PointPayment.AcceptPayment {
+			filters["exclude_type"] = string(constants.PaymentMethodTypePoint)
+		}
+	}
 
 	offset := (req.Page - 1) * req.Limit
 
@@ -116,6 +139,15 @@ func (p *PaymentMethodProcessorImpl) UpdatePaymentMethod(ctx context.Context, id
 		return nil, fmt.Errorf("payment method not found: %w", err)
 	}
 
+	// The EnakPoint method keeps its type, and no other method can become one.
+	if req.Type != nil {
+		wasPoint := existingPaymentMethod.Type == entities.PaymentMethodTypePoint
+		isPoint := *req.Type == constants.PaymentMethodTypePoint
+		if wasPoint != isPoint {
+			return nil, ErrSystemPaymentMethod
+		}
+	}
+
 	// Check name uniqueness if name is being updated
 	if req.Name != nil && *req.Name != existingPaymentMethod.Name {
 		exists, err := p.paymentMethodRepo.ExistsByName(ctx, existingPaymentMethod.OrganizationID, *req.Name, &id)
@@ -147,10 +179,13 @@ func (p *PaymentMethodProcessorImpl) UpdatePaymentMethod(ctx context.Context, id
 
 func (p *PaymentMethodProcessorImpl) DeletePaymentMethod(ctx context.Context, id uuid.UUID) error {
 	// Check if payment method exists
-	_, err := p.paymentMethodRepo.GetByID(ctx, id)
+	existing, err := p.paymentMethodRepo.GetByID(ctx, id)
 	if err != nil {
 		return fmt.Errorf("payment method not found: %w", err)
 	}
+	if existing.Type == entities.PaymentMethodTypePoint {
+		return ErrSystemPaymentMethod
+	}
 
 	// TODO: Check if payment method is being used in any payments
 	// For now, allow deletion

internal/processor/point_payment_method_db_test.go

@@ -0,0 +1,118 @@
+package processor
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"gorm.io/driver/postgres"
+	"gorm.io/gorm"
+	"gorm.io/gorm/logger"
+
+	"apskel-pos-be/internal/constants"
+	"apskel-pos-be/internal/models"
+	"apskel-pos-be/internal/repository"
+)
+
+// Needs TEST_DATABASE_URL pointing at a migrated database; see
+// internal/repository/wallet_repository_test.go.
+func TestPointPaymentMethod_AgainstPostgres(t *testing.T) {
+	dsn := os.Getenv("TEST_DATABASE_URL")
+	if dsn == "" {
+		t.Skip("TEST_DATABASE_URL not set")
+	}
+	db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{Logger: logger.Default.LogMode(logger.Silent)})
+	require.NoError(t, err)
+	ctx := context.Background()
+
+	org, user, accepting, refusing := uuid.New(), uuid.New(), uuid.New(), uuid.New()
+	exec := func(q string, args ...any) error { return db.Exec(q, args...).Error }
+	require.NoError(t, exec(`INSERT INTO organizations (id, name, plan_type) VALUES (?, 'pm test', 'basic')`, org))
+	require.NoError(t, exec(`INSERT INTO outlets (id, organization_id, name) VALUES (?, ?, 'Terima'), (?, ?, 'Tolak')`, accepting, org, refusing, org))
+	t.Cleanup(func() {
+		db.Exec(`DELETE FROM loyalty_setting_changes WHERE organization_id = ?`, org)
+		db.Exec(`DELETE FROM outlet_settings WHERE outlet_id IN ?`, []uuid.UUID{accepting, refusing})
+		db.Exec(`DELETE FROM outlets WHERE id IN ?`, []uuid.UUID{accepting, refusing})
+		db.Exec(`DELETE FROM payment_methods WHERE organization_id = ?`, org)
+		db.Exec(`DELETE FROM organizations WHERE id = ?`, org)
+	})
+
+	// A new organization gets exactly one EnakPoint method from the trigger.
+	var methods []struct {
+		ID   string
+		Name string
+		Type string
+	}
+	require.NoError(t, db.Raw(`SELECT id::text AS id, name, type FROM payment_methods WHERE organization_id = ?`, org).Scan(&methods).Error)
+	require.Len(t, methods, 1)
+	assert.Equal(t, "EnakPoint", methods[0].Name)
+	assert.Equal(t, "point", methods[0].Type)
+	pointID := uuid.MustParse(methods[0].ID)
+
+	// The database refuses a second one.
+	assert.Error(t, exec(`INSERT INTO payment_methods (organization_id, name, type) VALUES (?, 'EnakPoint 2', 'point')`, org))
+
+	txm := repository.NewTxManager(db)
+	settings := NewLoyaltySettingsProcessor(repository.NewLoyaltySettingsRepository(db), txm)
+	s, err := settings.Outlet(ctx, accepting)
+	require.NoError(t, err)
+	s.PointPayment.AcceptPayment = true
+	_, err = settings.UpdateOutlet(ctx, org, accepting, user, *s)
+	require.NoError(t, err)
+
+	p := NewPaymentMethodProcessorImpl(repository.NewPaymentMethodRepositoryImpl(db), settings)
+	cash, err := p.CreatePaymentMethod(ctx, &models.CreatePaymentMethodRequest{OrganizationID: org, Name: "Tunai", Type: constants.PaymentMethodTypeCash, IsActive: ptr(true)})
+	require.NoError(t, err)
+
+	// The API cannot make, retype or delete an EnakPoint method.
+	_, err = p.CreatePaymentMethod(ctx, &models.CreatePaymentMethodRequest{OrganizationID: org, Name: "Poin Lain", Type: constants.PaymentMethodTypePoint, IsActive: ptr(true)})
+	assert.ErrorIs(t, err, ErrSystemPaymentMethod)
+	toCash := constants.PaymentMethodTypeCash
+	_, err = p.UpdatePaymentMethod(ctx, pointID, &models.UpdatePaymentMethodRequest{Type: &toCash})
+	assert.ErrorIs(t, err, ErrSystemPaymentMethod)
+	toPoint := constants.PaymentMethodTypePoint
+	_, err = p.UpdatePaymentMethod(ctx, cash.ID, &models.UpdatePaymentMethodRequest{Type: &toPoint})
+	assert.ErrorIs(t, err, ErrSystemPaymentMethod)
+	assert.ErrorIs(t, p.DeletePaymentMethod(ctx, pointID), ErrSystemPaymentMethod)
+
+	// Renaming it is fine; its type stays.
+	name := "Bayar pakai EnakPoint"
+	renamed, err := p.UpdatePaymentMethod(ctx, pointID, &models.UpdatePaymentMethodRequest{Name: &name, Type: &toPoint})
+	require.NoError(t, err)
+	assert.Equal(t, name, renamed.Name)
+
+	// At the cashier it shows only where the outlet accepts EnakPoint.
+	types := func(outlet *uuid.UUID) []constants.PaymentMethodType {
+		t.Helper()
+		list, err := p.ListPaymentMethods(ctx, &models.ListPaymentMethodsRequest{OrganizationID: &org, OutletID: outlet, Page: 1, Limit: 50})
+		require.NoError(t, err)
+		var out []constants.PaymentMethodType
+		for _, m := range list.PaymentMethods {
+			out = append(out, m.Type)
+		}
+		assert.Equal(t, len(out), list.TotalCount, "the count matches what is listed")
+		return out
+	}
+	assert.ElementsMatch(t, []constants.PaymentMethodType{"cash", "point"}, types(&accepting))
+	assert.ElementsMatch(t, []constants.PaymentMethodType{"cash"}, types(&refusing))
+	assert.ElementsMatch(t, []constants.PaymentMethodType{"cash", "point"}, types(nil), "the dashboard, without an outlet, sees it")
+
+	// A payment either records both points_used and point_value, or neither.
+	var orderID uuid.UUID
+	require.NoError(t, exec(`INSERT INTO users (id, organization_id, name, email, password_hash, role) VALUES (?, ?, 'K', ?, 'x', 'cashier')`, user, org, user.String()+"@t"))
+	orderID = uuid.New()
+	require.NoError(t, exec(`INSERT INTO orders (id, organization_id, outlet_id, user_id, order_number, order_type, subtotal, tax_amount, total_amount)
+		VALUES (?, ?, ?, ?, ?, 'dine_in', 1000, 0, 1000)`, orderID, org, accepting, user, "PM-"+orderID.String()[:8]))
+	t.Cleanup(func() {
+		db.Exec(`DELETE FROM payments WHERE order_id = ?`, orderID)
+		db.Exec(`DELETE FROM orders WHERE id = ?`, orderID)
+		db.Exec(`DELETE FROM users WHERE id = ?`, user)
+	})
+	assert.Error(t, exec(`INSERT INTO payments (order_id, payment_method_id, amount, points_used) VALUES (?, ?, 1000, 1000)`, orderID, pointID))
+	assert.Error(t, exec(`INSERT INTO payments (order_id, payment_method_id, amount, points_used, point_value) VALUES (?, ?, 1000, 0, 1)`, orderID, pointID))
+	assert.NoError(t, exec(`INSERT INTO payments (order_id, payment_method_id, amount, points_used, point_value) VALUES (?, ?, 1000, 1000, 1)`, orderID, pointID))
+	assert.NoError(t, exec(`INSERT INTO payments (order_id, payment_method_id, amount) VALUES (?, ?, 1000)`, orderID, cash.ID))
+}

internal/repository/payment_method_repository.go

@@ -75,6 +75,8 @@ func (r *PaymentMethodRepositoryImpl) List(ctx context.Context, filters map[stri
 		case "search":
 			searchValue := "%" + value.(string) + "%"
 			query = query.Where("name ILIKE ? OR processor ILIKE ?", searchValue, searchValue)
+		case "exclude_type":
+			query = query.Where("type <> ?", value)
 		default:
 			query = query.Where(key+" = ?", value)
 		}

internal/service/payment_method_service.go

@@ -2,8 +2,10 @@ package service
 
 import (
 	"context"
+	"errors"
 
 	"apskel-pos-be/internal/appcontext"
+	"apskel-pos-be/internal/constants"
 	"apskel-pos-be/internal/contract"
 	"apskel-pos-be/internal/mappers"
 	"apskel-pos-be/internal/processor"
@@ -39,7 +41,7 @@ func (s *PaymentMethodServiceImpl) CreatePaymentMethod(ctx context.Context, cont
 	response, err := s.paymentMethodProcessor.CreatePaymentMethod(ctx, modelReq)
 	if err != nil {
 		return contract.BuildErrorResponse([]*contract.ResponseError{
-			contract.NewResponseError("PAYMENT_METHOD_CREATE_ERROR", "payment_method", err.Error()),
+			contract.NewResponseError(paymentMethodErrorCode(err, "PAYMENT_METHOD_CREATE_ERROR"), "payment_method", err.Error()),
 		})
 	}
 
@@ -84,7 +86,7 @@ func (s *PaymentMethodServiceImpl) UpdatePaymentMethod(ctx context.Context, id u
 	response, err := s.paymentMethodProcessor.UpdatePaymentMethod(ctx, id, modelReq)
 	if err != nil {
 		return contract.BuildErrorResponse([]*contract.ResponseError{
-			contract.NewResponseError("PAYMENT_METHOD_UPDATE_ERROR", "payment_method", err.Error()),
+			contract.NewResponseError(paymentMethodErrorCode(err, "PAYMENT_METHOD_UPDATE_ERROR"), "payment_method", err.Error()),
 		})
 	}
 
@@ -97,7 +99,7 @@ func (s *PaymentMethodServiceImpl) DeletePaymentMethod(ctx context.Context, id u
 	err := s.paymentMethodProcessor.DeletePaymentMethod(ctx, id)
 	if err != nil {
 		return contract.BuildErrorResponse([]*contract.ResponseError{
-			contract.NewResponseError("PAYMENT_METHOD_DELETE_ERROR", "payment_method", err.Error()),
+			contract.NewResponseError(paymentMethodErrorCode(err, "PAYMENT_METHOD_DELETE_ERROR"), "payment_method", err.Error()),
 		})
 	}
 
@@ -123,3 +125,12 @@ func (s *PaymentMethodServiceImpl) GetActivePaymentMethodsByOrganization(ctx con
 
 	return contract.BuildSuccessResponse(contractResponses)
 }
+
+// paymentMethodErrorCode answers a request to create, delete or retype the EnakPoint
+// method as a bad request instead of a server error.
+func paymentMethodErrorCode(err error, fallback string) string {
+	if errors.Is(err, processor.ErrSystemPaymentMethod) {
+		return constants.ValidationErrorCode
+	}
+	return fallback
+}

internal/validator/payment_method_validator.go

@@ -95,6 +95,7 @@ func (v *PaymentMethodValidatorImpl) isValidPaymentMethodType(paymentMethodType
 		string(constants.PaymentMethodTypeDigitalWallet),
 		string(constants.PaymentMethodTypeQR),
 		string(constants.PaymentMethodTypeEDC),
+		string(constants.PaymentMethodTypePoint),
 	}
 
 	for _, validType := range validTypes {

migrations/000094_add_point_payment_method.down.sql

@@ -0,0 +1,16 @@
+ALTER TABLE payments
+    DROP CONSTRAINT IF EXISTS chk_payments_point_pair,
+    DROP COLUMN IF EXISTS point_value,
+    DROP COLUMN IF EXISTS points_used;
+
+DROP TRIGGER IF EXISTS trigger_create_point_payment_method ON organizations;
+DROP FUNCTION IF EXISTS create_point_payment_method();
+
+-- Fails if an EnakPoint method has been used by a payment, which is the point: those
+-- payments would lose their method.
+DELETE FROM payment_methods WHERE type = 'point';
+DROP INDEX IF EXISTS uq_payment_methods_point_per_organization;
+
+ALTER TABLE payment_methods DROP CONSTRAINT IF EXISTS payment_methods_type_check;
+ALTER TABLE payment_methods ADD CONSTRAINT payment_methods_type_check
+    CHECK (type IN ('cash', 'card', 'digital_wallet'));

migrations/000094_add_point_payment_method.up.sql

@@ -0,0 +1,45 @@
+-- Paying with EnakPoint (docs/prd-point-coin.md F9, §8, §10.5).
+
+-- A new payment method type. Every organization has exactly one method of it, made by
+-- the system, which cannot be deleted or change type.
+ALTER TABLE payment_methods DROP CONSTRAINT IF EXISTS payment_methods_type_check;
+ALTER TABLE payment_methods ADD CONSTRAINT payment_methods_type_check
+    CHECK (type IN ('cash', 'card', 'digital_wallet', 'point'));
+
+CREATE UNIQUE INDEX uq_payment_methods_point_per_organization ON payment_methods(organization_id)
+    WHERE type = 'point';
+
+INSERT INTO payment_methods (organization_id, name, type, is_active)
+SELECT id, 'EnakPoint', 'point', TRUE FROM organizations
+ON CONFLICT (organization_id) WHERE type = 'point' DO NOTHING;
+
+-- New organizations get theirs the same way they get their walk-in customer, whatever
+-- code path creates them.
+CREATE OR REPLACE FUNCTION create_point_payment_method()
+RETURNS TRIGGER AS $$
+BEGIN
+    INSERT INTO payment_methods (organization_id, name, type, is_active)
+    VALUES (NEW.id, 'EnakPoint', 'point', TRUE)
+    ON CONFLICT (organization_id) WHERE type = 'point' DO NOTHING;
+    RETURN NEW;
+END;
+$$ LANGUAGE plpgsql;
+
+CREATE TRIGGER trigger_create_point_payment_method
+    AFTER INSERT ON organizations
+    FOR EACH ROW
+    EXECUTE FUNCTION create_point_payment_method();
+
+-- A payment made with EnakPoint records how many were used and the rupiah value of one
+-- at that moment. The value is frozen so a refund returns exactly the EnakPoint used,
+-- whatever the value is by then.
+--
+-- Written so it never evaluates to NULL: the form in the PRD, (both NULL) OR (both
+-- > 0), is NULL for points_used = 1000 with point_value NULL, and a CHECK only rejects
+-- FALSE, so a payment could lose its frozen value.
+ALTER TABLE payments
+    ADD COLUMN points_used BIGINT,
+    ADD COLUMN point_value DECIMAL(10,2),
+    ADD CONSTRAINT chk_payments_point_pair CHECK (
+        (points_used IS NULL) = (point_value IS NULL)
+        AND (points_used IS NULL OR (points_used > 0 AND point_value > 0)));