Initial commit: Open sourcing all of the Maple Open Technologies code.

cloud/maplefile-backend/internal/usecase/collection/get.go

@@ -0,0 +1,65 @@
+// monorepo/cloud/backend/internal/maplefile/usecase/collection/get.go
+package collection
+
+import (
+	"context"
+
+	"go.uber.org/zap"
+
+	"github.com/gocql/gocql"
+	"codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/config"
+	dom_collection "codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/internal/domain/collection"
+	"codeberg.org/mapleopentech/monorepo/cloud/maplefile-backend/pkg/httperror"
+)
+
+type GetCollectionUseCase interface {
+	Execute(ctx context.Context, id gocql.UUID) (*dom_collection.Collection, error)
+}
+
+type getCollectionUseCaseImpl struct {
+	config *config.Configuration
+	logger *zap.Logger
+	repo   dom_collection.CollectionRepository
+}
+
+func NewGetCollectionUseCase(
+	config *config.Configuration,
+	logger *zap.Logger,
+	repo dom_collection.CollectionRepository,
+) GetCollectionUseCase {
+	logger = logger.Named("GetCollectionUseCase")
+	return &getCollectionUseCaseImpl{config, logger, repo}
+}
+
+func (uc *getCollectionUseCaseImpl) Execute(ctx context.Context, id gocql.UUID) (*dom_collection.Collection, error) {
+	//
+	// STEP 1: Validation.
+	//
+
+	e := make(map[string]string)
+	if id.String() == "" {
+		e["id"] = "Collection ID is required"
+	}
+	if len(e) != 0 {
+		uc.logger.Warn("Failed validating collection retrieval",
+			zap.Any("error", e))
+		return nil, httperror.NewForBadRequest(&e)
+	}
+
+	//
+	// STEP 2: Get from database.
+	//
+
+	collection, err := uc.repo.Get(ctx, id)
+	if err != nil {
+		return nil, err
+	}
+
+	if collection == nil {
+		uc.logger.Debug("Collection not found",
+			zap.Any("id", id))
+		return nil, httperror.NewForNotFoundWithSingleField("message", "Collection not found")
+	}
+
+	return collection, nil
+}