2 files changed, 97 insertions, 33 deletions

diff --git a/core/data.go b/core/data.go
index 7ccc4f9..ddf1db8 100644
--- a/core/data.go
+++ b/core/data.go
@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"io"
 	"strings"
+	"time"
 )
 
 type Marshaler interface {
@@ -21,63 +22,72 @@ const (
 	TypeTest               = 0xFF
 )
 
+func ReadDataType(r io.Reader) (DataType, error) {
+	var data uint8
+	if err := read(r, &data); err != nil {
+		return TypeUnknown, err
+	}
+
+	dType := DataType(data)
+
+	return dType, nil
+}
+
 type Handshake struct {
 	Version uint8
 }
 
-func (h Handshake) Marshal() []any {
-	return []any{h.Version}
+func (t Handshake) Marshal() []any {
+	return []any{t.Version}
 }
 
 func ReadHandshake(r io.Reader) (Handshake, error) {
-	var d Handshake
-	err := read(r, &d.Version)
-	return d, err
+	var t Handshake
+	err := read(r, &t.Version)
+	return t, err
 }
 
 type Test struct {
 	Message string
 }
 
-func ReadTest(r io.Reader) (Test, error) {
-	var d Test
-	err := readString(r, &d.Message)
-	return d, err
+func (t Test) Marshal() []any {
+	return []any{append([]byte(t.Message), 0x0)}
 }
 
-func (h Test) Marshal() []any {
-	return []any{append([]byte(h.Message), 0x0)}
+func ReadTest(r io.Reader) (Test, error) {
+	var t Test
+	err := readString(r, &t.Message)
+	return t, err
 }
 
-func Read(r io.Reader) (any, error) {
-	dType, err := ReadDataType(r)
-	if err != nil {
-		return nil, fmt.Errorf("cannot read data type", err)
-	}
+type Ping struct{}
 
-	switch dType {
-	case TypeUnknown:
-		return nil, fmt.Errorf("cannot read data type 0x00 (TypeUnknown)")
-	case TypeHandshake:
-		return ReadHandshake(r)
-	case TypeTest:
-		return ReadTest(r)
-	default:
-		return nil, fmt.Errorf("unsupported type: %v", dType)
-	}
+func (t Ping) Marshal() []any {
+	return []any{}
 }
 
-func ReadDataType(r io.Reader) (DataType, error) {
-	var data uint8
-	if err := read(r, &data); err != nil {
-		return TypeUnknown, err
-	}
+type Pong struct {
+	Timestamp time.Time
+}
 
-	dType := DataType(data)
+func (t Pong) Marshal() []any {
+	return []any{uint64(t.Timestamp.Unix())}
+}
 
-	return dType, nil
+func ReadPong(r io.Reader) (Pong, error) {
+	var (
+		t         Pong
+		timestamp uint64
+	)
+
+	err := read(r, &timestamp)
+	t.Timestamp = time.Unix(int64(timestamp), 0)
+	return t, err
 }
 
+//
+
 func readString(r io.Reader, ptr *string) error {
 	var (
 		sb  strings.Builder
diff --git a/core/network.go b/core/network.go
index 50c398f..c662981 100644
--- a/core/network.go
+++ b/core/network.go
@@ -3,7 +3,10 @@ package core
 import (
 	"encoding/binary"
 	"fmt"
+	"io"
+	"log"
 	"net"
+	"time"
 )
 
 func Send(conn net.Conn, dataType DataType, data Marshaler) error {
@@ -19,3 +22,54 @@ func Send(conn net.Conn, dataType DataType, data Marshaler) error {
 
 	return nil
 }
+
+func Read(r io.Reader) (any, error) {
+	dType, err := ReadDataType(r)
+	if err != nil {
+		return nil, fmt.Errorf("cannot read data type", err)
+	}
+
+	switch dType {
+	case TypeUnknown:
+		return nil, fmt.Errorf("cannot read data type 0x00 (TypeUnknown)")
+	case TypeHandshake:
+		return ReadHandshake(r)
+	case TypePing:
+		return Ping{}, nil
+	case TypePong:
+		return ReadPong(r)
+	case TypeTest:
+		return ReadTest(r)
+	default:
+		return nil, fmt.Errorf("unsupported type: %v", dType)
+	}
+}
+
+func Loop(conn net.Conn) error {
+	for {
+		d, err := Read(conn)
+		if err != nil {
+			return fmt.Errorf("cannot read data: %v", err)
+		}
+
+		if err := handleEvent(d, conn); err != nil {
+			return fmt.Errorf("cannot handle event: %v", err)
+		}
+	}
+}
+
+func handleEvent(data any, conn net.Conn) error {
+	switch v := data.(type) {
+	case Handshake:
+	case Ping:
+		log.Print("received ping")
+		return Send(conn, TypePong, Pong{time.Now()})
+	case Pong:
+		log.Print("received pong ", v.Timestamp)
+	case Test:
+	default:
+		return fmt.Errorf("unknown type")
+	}
+
+	return nil
+}