initial commit

internal/storage/inmemory/mapper.go

@@ -0,0 +1,40 @@
+package inmemory
+
+import (
+	"context"
+	"fmt"
+
+	"git.loyso.art/frx/eway/internal/entity"
+	"git.loyso.art/frx/eway/internal/storage"
+)
+
+type mapper struct {
+	categoryIDByName map[string]int64
+	base             storage.Repository
+}
+
+func NewMapper(ctx context.Context, r storage.Repository) (*mapper, error) {
+	categories, err := r.Category().List(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("listing categories: %w", err)
+	}
+
+	catsByName := make(map[string]int64, len(categories))
+	for _, category := range categories {
+		catsByName[category.Name] = category.ID
+	}
+
+	return &mapper{
+		categoryIDByName: catsByName,
+		base:             r,
+	}, nil
+}
+
+func (m *mapper) CategoryNameToID(ctx context.Context, name string) (int64, error) {
+	out, ok := m.categoryIDByName[name]
+	if !ok {
+		return 0, entity.ErrNotFound
+	}
+
+	return out, nil
+}