feat: simple builder

authz/builder.go

@@ -2,6 +2,7 @@ package authz
 
 import (
 	"context"
+	"strings"
 
 	"github.com/openfga/go-sdk/client"
 	"github.com/zeiss/pkg/cast"
@@ -17,6 +18,18 @@ type Object string
 // Relation is the relation between the user and the object.
 type Relation string
 
+// NoopUser is a user that represents no user.
+const NoopUser User = ""
+
+// NoopRelation is a relation that represents no relation.
+const NoopRelation Relation = ""
+
+// NoopObject is an object that represents no object.
+const NoopObject Object = ""
+
+// Stringer create a string an adds it to the representation.
+type Stringer func() string
+
 // Store is an interface that provides methods for transactional operations on the authz database.
 type Store[Tx any] interface {
 	// Allowed checks if the user is allowed to perform the operation on the object.
@@ -144,3 +157,69 @@ func (s *storeImpl[Tx]) DeleteTuple(ctx context.Context, user User, object Objec
 
 	return nil
 }
+
+// DefaultSeparator is the default separator for entities.
+const DefaultSeparator = "/"
+
+// DefaultNamespaceSeparator is the default separator for namespaces.
+const DefaultNamespaceSeparator = ":"
+
+// EntitiesString is a type that represents a list of entities.
+func EntityString[E Entities](e E) string {
+	return conv.String(e)
+}
+
+// Entities is a type that represents a list of entities.
+type Entities interface {
+	User | Relation | Object
+}
+
+// NewEntity returns a new User.
+func NewEntity[E Entities](s ...Stringer) E {
+	u := ""
+
+	for _, v := range s {
+		u += v()
+	}
+
+	return E(u)
+}
+
+// NewUser returns a new User.
+func NewUser(s ...Stringer) User {
+	return NewEntity[User](s...)
+}
+
+// NewRelation returns a new Relation.
+func NewRelation(s ...Stringer) Relation {
+	return NewEntity[Relation](s...)
+}
+
+// NewObject returns a new Object.
+func NewObject(s ...Stringer) Object {
+	return NewEntity[Object](s...)
+}
+
+// Namespace adds a namespace to the entity.
+func Namespace(namespace string, sep ...string) Stringer {
+	return func() string {
+		s := DefaultNamespaceSeparator
+
+		if len(sep) > 0 {
+			s = sep[0]
+		}
+
+		if namespace == "" {
+			return ""
+		}
+
+		return namespace + s
+	}
+}
+
+// Join joins the entities with the separator.
+func Join(sep string, entities ...string) Stringer {
+	return func() string {
+		return strings.Join(entities, sep)
+	}
+}