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

This reverts commit 4e24f9bbb0.

internal/handler/spin_game_handler.go

@@ -1,10 +1,13 @@
 package handler
 
 import (
+	"errors"
+
 	"apskel-pos-be/internal/constants"
 	"apskel-pos-be/internal/contract"
 	"apskel-pos-be/internal/mappers"
 	"apskel-pos-be/internal/models"
+	"apskel-pos-be/internal/processor"
 	"apskel-pos-be/internal/service"
 	"apskel-pos-be/internal/util"
 
@@ -49,8 +52,14 @@ func (h *SpinGameHandler) PlaySpinGame(c *gin.Context) {
 	// Play the spin game
 	response, err := h.spinGameService.PlaySpinGame(c.Request.Context(), customerID.(string), modelReq)
 	if err != nil {
+		// Not enough EnakCoin, an inactive game or a prize that just ran out is the
+		// customer's to fix, not a server failure.
+		code := constants.InternalServerErrorCode
+		if errors.Is(err, processor.ErrGamePlayRefused) {
+			code = constants.ValidationErrorCode
+		}
 		util.HandleResponse(c.Writer, c.Request, contract.BuildErrorResponse([]*contract.ResponseError{
-			contract.NewResponseError(constants.InternalServerErrorCode, constants.SpinGameHandlerEntity, err.Error()),
+			contract.NewResponseError(code, constants.SpinGameHandlerEntity, err.Error()),
 		}), "SpinGameHandler::PlaySpinGame")
 		return
 	}