Refactor: Implement modular design with connection handling, event bus, and status client

connection.go

@@ -0,0 +1,108 @@
+package strom
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net"
+
+	"github.com/admin-else/queser"
+	"github.com/admin-else/queser/generated"
+)
+
+var BadPacketTypeError = errors.New("bad packet type")
+
+type Actor int
+
+const (
+	Server Actor = iota
+	Client
+)
+
+func (a Actor) SendDirection() queser.Direction {
+	switch a {
+	case Server:
+		return queser.ToClient
+	case Client:
+		return queser.ToServer
+	default:
+		panic("invalid actor")
+	}
+}
+
+func (a Actor) ReceiveDirection() queser.Direction {
+	switch a {
+	case Server:
+		return queser.ToServer
+	case Client:
+		return queser.ToClient
+	default:
+		panic("invalid actor")
+	}
+}
+
+type Connection struct {
+	io.ReadWriteCloser
+	CompressionThreshold int32
+	State                queser.State
+	Actor                Actor
+	Version              string
+}
+
+func (c *Connection) Send(packet any) (err error) {
+	packetIdentifier := generated.TypeToPacketIdentifier(c.Version, c.Actor.SendDirection(), c.State, packet)
+	if packetIdentifier == "" {
+		err = BadPacketTypeError
+		return
+	}
+	rawPacketBuffer := bytes.NewBuffer(nil)
+	err = generated.EncodePacket(c.Version, c.Actor.SendDirection(), c.State, packetIdentifier, packet, rawPacketBuffer)
+	if err != nil {
+		return
+	}
+	var packetBytes []byte
+	if c.CompressionThreshold > 0 {
+		panic("todo")
+	} else {
+		packetBytes = rawPacketBuffer.Bytes()
+	}
+	err = queser.VarInt(len(packetBytes)).Encode(c)
+	if err != nil {
+		return
+	}
+	_, err = c.Write(packetBytes)
+	return
+}
+
+func (c *Connection) Receive() (packet any, err error) {
+	var packetLen queser.VarInt
+	packetLen, err = packetLen.Decode(c)
+	if err != nil {
+		return
+	}
+	rawPacketBytes, err := io.ReadAll(io.LimitReader(c, int64(packetLen)))
+	if err != nil {
+		return
+	}
+	var packetBytes []byte
+	if c.CompressionThreshold > 0 {
+		panic("todo")
+	} else {
+		packetBytes = rawPacketBytes
+	}
+	packet, err = generated.DecodePacket(c.Version, c.Actor.ReceiveDirection(), c.State, bytes.NewReader(packetBytes))
+	return
+}
+
+func ClientConnect(addr string) (ret *Connection, err error) {
+	ret = &Connection{}
+	ret.Version = "1.21.8"
+	ret.State = queser.Handshaking
+	ret.CompressionThreshold = -1
+	ret.Actor = Client
+	ret.ReadWriteCloser, err = net.Dial("tcp", addr)
+	if err != nil {
+		return
+	}
+	return
+}