grpc

type ClientError struct {
	// Name is a name for this class of errors.
	Name string
	// Message contains the specific error details.
	Message string
	// Service is the name of the service.
	Service string
	// Method is the name of the service method.
	Method string
	// Is the error temporary?
	Temporary bool
	// Is the error a timeout?
	Timeout bool
	// Is the error a server-side fault?
	Fault bool
}

type ErrorMapper func(string, error) (ErrorMapping, bool, error)

type ErrorMapping struct {
	// Code is the gRPC status code for the designed error.
	Code codes.Code
	// Detail is the designed protocol buffer error detail.
	Detail protoiface.MessageV1
}

type Invoker interface {
	Invoke(ctx context.Context, req any) (res any, err error)
}

type RemoteFunc func(ctx context.Context, reqpb any, opts ...grpc.CallOption) (respb any, err error)

type RequestDecoder func(ctx context.Context, pb any, md metadata.MD) (v any, err error)

type RequestEncoder func(ctx context.Context, v any, md *metadata.MD) (pb any, err error)

type ResponseContractCase struct {
	// ID is stable while the service contract is unchanged.
	ID string
	// Kind identifies a successful result or service error.
	Kind ResponseContractCaseKind
	// StatusCode is the declared gRPC status code.
	StatusCode codes.Code
	// MessageType is the protobuf full name of a successful response message.
	MessageType string
	// ErrorName is the declared service error name.
	ErrorName string
	// DetailType is the protobuf full name of the expected status detail.
	DetailType string
	// RequiredHeaders lists required response metadata keys.
	RequiredHeaders []string
	// RequiredTrailers lists required trailer metadata keys.
	RequiredTrailers []string
	// Stream describes a supported streaming completion contract.
	Stream *StreamingResponseContract
}

type ResponseContractCaseKind string

type ResponseContractObservation struct {
	// Message is the unary response message.
	Message proto.Message
	// Error is the unary call error.
	Error error
	// Headers contains response header metadata.
	Headers metadata.MD
	// Trailers contains response trailer metadata.
	Trailers metadata.MD
	// Messages contains server-stream messages in receive order.
	Messages []proto.Message
	// TerminalError is the final server-stream receive error.
	TerminalError error
}

type ResponseDecoder func(ctx context.Context, pb any, hdr, trlr metadata.MD) (v any, err error)

type ResponseEncoder func(ctx context.Context, v any, hdr, trlr *metadata.MD) (pb any, err error)

type StreamHandler interface {
	// Handle handles a streaming RPC.
	//
	// input contains the endpoint payload (if any) and generated
	// endpoint stream.
	Handle(ctx context.Context, input any) (err error)
	// Decode decodes the protocol buffer message and metadata to
	// the service type. For client-side and bidirectional streams,
	// the message is nil.
	Decode(ctx context.Context, reqpb any) (req any, err error)
}

type StreamServerSpec struct {
	// Service is the Loom service name.
	Service string
	// Method is the Loom method name.
	Method string
	// Decode creates the typed endpoint stream input.
	Decode func(context.Context) (any, error)
	// Handle invokes the typed streaming endpoint.
	Handle func(context.Context, any) error
	// MapError maps designed service errors to gRPC status contracts.
	MapError ErrorMapper
}

type StreamingResponseContract struct {
	// Direction is the designed stream direction.
	Direction string
	// Terminal identifies the expected completion behavior.
	Terminal string
}

type UnaryHandler interface {
	// Handle handles a unary RPC.
	//
	// It takes a protocol buffer message type and returns a
	// protocol buffer message type and any error when executing the
	// RPC.
	Handle(ctx context.Context, reqpb any) (respb any, err error)
}

type UnaryServerSpec struct {
	// Service is the Loom service name.
	Service string
	// Method is the Loom method name.
	Method string
	// Handler decodes, invokes, and encodes the typed endpoint.
	Handler UnaryHandler
	// MapError maps designed service errors to gRPC status contracts.
	MapError ErrorMapper
}