package codec

import (
	"io"
)

const (
	Error MessageType = iota
	Request
	Response
	Publication
)

type MessageType int

// Takes in a connection/buffer and returns a new Codec
type NewCodec func(io.ReadWriteCloser) Codec

// Codec encodes/decodes various types of
// messages used within go-micro
type Codec interface {
	ReadHeader(*Message, MessageType) error
	ReadBody(interface{}) error
	Write(*Message, interface{}) error
	Close() error
	String() string
}

// Message represents detailed information about
// the communication, likely followed by the body.
// In the case of an error, body may be nil.
type Message struct {
	Id      uint64
	Type    MessageType
	Target  string
	Method  string
	Error   string
	Headers map[string]string
}