service

type CallFunc func(ctx Context, arg []byte) (ret interface{}, err error)

type Context interface {
	context.Context

	// SetContext can be used to wrap the context.Context with additonal deadlines, ...
	SetContext(ctx context.Context)

	// Session returns the current active session.
	Session() Session

	// Header returns the raw header byte slice defined by the key. Returns nil if not present.
	Header(key string) []byte

	// Data returns the value defined by the key. Returns nil if not present.
	Data(key string) interface{}

	// SetData sets the value defined by the key.
	SetData(key string, v interface{})
}

type Error interface {
	// Embeds the standard go error interface.
	error

	// Msg returns a textual explanation of the error and should
	// NOT contain sensitive information about the application.
	Msg() string

	// Code returns an integer that can give a hint about the
	// type of error that occurred.
	Code() int
}

type Hook interface {
	// Close is called if the service closes.
	Close() error

	// OnSession is called if a new client session is connected to the service.
	// RPC and stream routines are handled after this hook.
	// Do not use the stream after returning from this hook.
	// Return an error to close the session and abort the initialization process.
	OnSession(s Session, stream transport.Stream) error

	// OnSessionClosed is called as soon as the session closes.
	OnSessionClosed(s Session)

	// OnCall is called before a call request.
	// Return an error to abort the call.
	OnCall(ctx Context, id string, callKey uint32) error

	// OnCallDone is called after a call request.
	// The context is the same as from the OnCall hook.
	// If err == nil, then the call completed successfully.
	OnCallDone(ctx Context, id string, callKey uint32, err error)

	// OnCallCanceled is called, if a call is canceled.
	// The context is the same as from the OnCall hook.
	OnCallCanceled(ctx Context, id string, callKey uint32)

	// OnStream is called during a new stream setup.
	// Return an error to abort the stream setup.
	OnStream(ctx Context, id string, stream transport.Stream) error
}

type Hooks []Hook

type Options struct {
	// ListenAddr specifies the listen address for the server. This value is passed to the transport backend.
	ListenAddr string

	// Transport specifies the communication backend. This value must be set.
	Transport transport.Transport

	// Closer defines the closer instance. A default closer will be created if unspecified.
	Closer closer.Closer

	// Codec defines the transport encoding. A default codec will be used if unspecified.
	Codec codec.Codec

	// Hooks specifies the hooks executed during certain actions. The order of the hooks is stricly followed.
	Hooks Hooks

	// Log specifies the default logger backend. A default logger will be used if unspecified.
	Log *zerolog.Logger

	// AcceptConnWorkers specifies the routines accepting new connections.
	AcceptConnWorkers int

	// SessionIDLen specifies the length of each session ID.
	SessionIDLen uint

	// HandshakeTimeout specifies the timeout for the initial handshake.
	HandshakeTimeout time.Duration

	// PrintPanicStackTraces prints stack traces of catched panics.
	PrintPanicStackTraces bool

	// SendInternalErrors sends all errors to the client, even if the Error interface is not satisfied.
	SendInternalErrors bool
}

type Service interface {
	closer.Closer

	RegisterCall(id string, f CallFunc)
	RegisterStream(id string, f StreamFunc)
	Run() error
}

type Session interface {
	closer.Closer

	ID() string
	LocalAddr() net.Addr
	RemoteAddr() net.Addr
}

type StreamFunc func(ctx Context, stream transport.Stream)