feat: initial Netts energy orchestrator

pkg/errors/api_error.go

@@ -0,0 +1,36 @@
+package errors
+
+import "fmt"
+
+// APIError represents a structured error from an upstream API.
+type APIError struct {
+	Code       int
+	Message    string
+	HTTPStatus int
+}
+
+func (e *APIError) Error() string {
+	if e == nil {
+		return "<nil>"
+	}
+	if e.HTTPStatus > 0 {
+		return fmt.Sprintf("api error: status=%d code=%d message=%s", e.HTTPStatus, e.Code, e.Message)
+	}
+	return fmt.Sprintf("api error: code=%d message=%s", e.Code, e.Message)
+}
+
+// Temporary returns true when the error is potentially recoverable.
+func (e *APIError) Temporary() bool {
+	if e == nil {
+		return false
+	}
+	if e.HTTPStatus >= 500 {
+		return true
+	}
+	switch e.Code {
+	case 429:
+		return true
+	default:
+		return false
+	}
+}