From 4bc8c8f53f4af955615c2170958be0d9fa94d8a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20D=C3=B6ll?= <sebastian@katallaxie.dev>
Date: Wed, 26 Jun 2024 21:21:49 +0000
Subject: [PATCH] chore: add fga interface

---
 go.mod             |  3 +-
 openfga/builder.go | 86 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+), 1 deletion(-)
 create mode 100644 openfga/builder.go

diff --git a/go.mod b/go.mod
index 76342e7..649656c 100644
--- a/go.mod
+++ b/go.mod
@@ -1,6 +1,7 @@
 module github.com/zeiss/fiber-authz
 
-go 1.21.9
+go 1.22
+
 toolchain go1.22.4
 
 require (
diff --git a/openfga/builder.go b/openfga/builder.go
new file mode 100644
index 0000000..589b84e
--- /dev/null
+++ b/openfga/builder.go
@@ -0,0 +1,86 @@
+package openfga
+
+import (
+	"context"
+
+	"github.com/openfga/go-sdk/client"
+)
+
+// DatastoreError is an error that occurred while executing a operation.
+type DatastoreError struct {
+	// Details are details to the operation
+	Details string
+	// Err is the error that occurred.
+	Err error
+}
+
+// Error implements the error interface.
+func (e *DatastoreError) Error() string { return e.Details + ": " + e.Err.Error() }
+
+// Unwrap implements the errors.Wrapper interface.
+func (e *DatastoreError) Unwrap() error { return e.Err }
+
+// NewDatastoreError returns a new QueryError.
+func NewDatastoreError(details string, err error) *DatastoreError {
+	return &DatastoreError{
+		Details: details,
+		Err:     err,
+	}
+}
+
+// Datastore provides methods for transactional operations.
+type Datastore[R, W any] interface {
+	// Read starts a read only transaction.
+	Read(context.Context, func(context.Context, R) error) error
+	// ReadWriteTx starts a read write transaction.
+	ReadWrite(context.Context, func(context.Context, W) error) error
+}
+
+type datastoreImpl[R, W any] struct {
+	r      ReadFactory[R]
+	rw     ReadWriteFactory[W]
+	client client.SdkClient
+}
+
+// ReadFactory is a function that creates a new instance of Datastore.
+type ReadFactory[R any] func(client.SdkClient) (R, error)
+
+// ReadWriteFactory is a function that creates a new instance of Datastore.
+type ReadWriteFactory[W any] func(client.SdkClient) (W, error)
+
+// NewDatastore returns a new instance of db.
+func NewDatastore[R, W any](client client.SdkClient, r ReadFactory[R], rw ReadWriteFactory[W]) (Datastore[R, W], error) {
+	return &datastoreImpl[R, W]{
+		client: client,
+	}, nil
+}
+
+// ReadWriteTx starts a read only transaction.
+func (d *datastoreImpl[R, W]) ReadWrite(ctx context.Context, fn func(context.Context, W) error) error {
+	tx, err := d.rw(d.client)
+	if err != nil {
+		return NewDatastoreError("read/write datastore", err)
+	}
+
+	err = fn(ctx, tx)
+	if err != nil {
+		return NewDatastoreError("read/write datastore", err)
+	}
+
+	return nil
+}
+
+// ReadTx starts a read only transaction.
+func (d *datastoreImpl[R, W]) Read(ctx context.Context, fn func(context.Context, R) error) error {
+	tx, err := d.r(d.client)
+	if err != nil {
+		return NewDatastoreError("read datastore", err)
+	}
+
+	err = fn(ctx, tx)
+	if err != nil {
+		return NewDatastoreError("read datastore", err)
+	}
+
+	return nil
+}