Reapply "feat(loyalty): EnakPoint & EnakCoin" (#32)

This reverts commit 4e24f9bbb0.

internal/handler/point_payment_handler.go

@@ -0,0 +1,28 @@
+package handler
+
+import (
+	"github.com/gin-gonic/gin"
+
+	"apskel-pos-be/internal/appcontext"
+	"apskel-pos-be/internal/service"
+	"apskel-pos-be/internal/util"
+)
+
+// PointPaymentHandler serves GET /orders/:id/point-payment/preview
+// (docs/prd-point-coin.md F9).
+type PointPaymentHandler struct {
+	pointPaymentService service.PointPaymentService
+}
+
+func NewPointPaymentHandler(pointPaymentService service.PointPaymentService) *PointPaymentHandler {
+	return &PointPaymentHandler{pointPaymentService: pointPaymentService}
+}
+
+func (h *PointPaymentHandler) Preview(c *gin.Context) {
+	orderID, ok := parseUUIDParam(c, "id", "PointPaymentHandler::Preview")
+	if !ok {
+		return
+	}
+	ctx := c.Request.Context()
+	util.HandleResponse(c.Writer, c.Request, h.pointPaymentService.Preview(ctx, appcontext.FromGinContext(ctx), orderID), "PointPaymentHandler::Preview")
+}