Implemented basic server

main.go

@@ -1,21 +1,194 @@
 package main
 
 import (
+	"encoding/json"
 	"fmt"
+	"net"
 )
 
-//TIP <p>To run your code, right-click the code and select <b>Run</b>.</p> <p>Alternatively, click
-// the <icon src="AllIcons.Actions.Execute"/> icon in the gutter and select the <b>Run</b> menu item from here.</p>
+const (
+	HandshakePacketID = 0x00
+	StatusRequestID   = 0x00
+	StatusResponseID  = 0x00
+)
+
+type HandshakePacket struct {
+	ProtocolVersion int
+	ServerAddress   string
+	ServerPort      uint16
+	NextState       int
+}
+
+type StatusResponse struct {
+	Version     VersionInfo `json:"version"`
+	Players     PlayerInfo  `json:"players"`
+	Description Chat        `json:"description"`
+}
+
+type VersionInfo struct {
+	Name     string `json:"name"`
+	Protocol int    `json:"protocol"`
+}
+
+type PlayerInfo struct {
+	Max    int      `json:"max"`
+	Online int      `json:"online"`
+	Sample []Player `json:"sample"`
+}
+
+type Player struct {
+	Name string `json:"name"`
+	ID   string `json:"id"`
+}
+
+type Chat struct {
+	Text string `json:"text"`
+}
 
 func main() {
-	//TIP <p>Press <shortcut actionId="ShowIntentionActions"/> when your caret is at the underlined text
-	// to see how GoLand suggests fixing the warning.</p><p>Alternatively, if available, click the lightbulb to view possible fixes.</p>
-	s := "gopher"
-	fmt.Println("Hello and welcome, %s!", s)
+	listener, err := net.Listen("tcp", ":25565")
+	if err != nil {
+		fmt.Println("Error starting server:", err)
+		return
+	}
+	defer listener.Close()
 
-	for i := 1; i <= 5; i++ {
-		//TIP <p>To start your debugging session, right-click your code in the editor and select the Debug option.</p> <p>We have set one <icon src="AllIcons.Debugger.Db_set_breakpoint"/> breakpoint
-		// for you, but you can always add more by pressing <shortcut actionId="ToggleLineBreakpoint"/>.</p>
-		fmt.Println("i =", 100/i)
+	fmt.Println("Server started on port 25565")
+
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			fmt.Println("Error accepting connection:", err)
+			continue
+		}
+
+		go handleConnection(conn)
 	}
 }
+
+func handleConnection(conn net.Conn) {
+	var packetID byte
+	if err := readByte(conn, &packetID); err != nil {
+		fmt.Println("Error reading packet ID:", err)
+		return
+	}
+
+	if packetID == HandshakePacketID {
+		handleHandshake(conn)
+	}
+}
+
+func handleHandshake(conn net.Conn) {
+	var handshake HandshakePacket
+	if err := readHandshakePacket(conn, &handshake); err != nil {
+		fmt.Println("Error reading handshake packet:", err)
+		return
+	}
+
+	if handshake.NextState == 1 {
+		handleStatusRequest(conn)
+	}
+}
+
+func handleStatusRequest(conn net.Conn) {
+	var packetID byte
+	if err := readByte(conn, &packetID); err != nil {
+		fmt.Println("Error reading packet ID:", err)
+		return
+	}
+
+	if packetID == StatusRequestID {
+		status := StatusResponse{
+			Version: VersionInfo{
+				Name:     "1.17.1",
+				Protocol: 756,
+			},
+			Players: PlayerInfo{
+				Max:    100,
+				Online: 5,
+				Sample: []Player{},
+			},
+			Description: Chat{
+				Text: "A Minecraft Server",
+			},
+		}
+
+		response, err := json.Marshal(status)
+		if err != nil {
+			fmt.Println("Error marshaling status response:", err)
+			return
+		}
+
+		if err := writeByte(conn, StatusResponseID); err != nil {
+			fmt.Println("Error writing response ID:", err)
+			return
+		}
+
+		if err := writeVarInt(conn, len(response)); err != nil {
+			fmt.Println("Error writing response length:", err)
+			return
+		}
+
+		if _, err := conn.Write(response); err != nil {
+			fmt.Println("Error writing response:", err)
+			return
+		}
+	}
+}
+
+func readByte(conn net.Conn, b *byte) error {
+	buf := make([]byte, 1)
+	_, err := conn.Read(buf)
+	if err != nil {
+		return err
+	}
+	*b = buf[0]
+	return nil
+}
+
+func writeByte(conn net.Conn, b byte) error {
+	_, err := conn.Write([]byte{b})
+	return err
+}
+
+func writeVarInt(conn net.Conn, value int) error {
+	for {
+		temp := byte(value & 0x7F)
+		value >>= 7
+		if value != 0 {
+			temp |= 0x80
+		}
+		if _, err := conn.Write([]byte{temp}); err != nil {
+			return err
+		}
+		if value == 0 {
+			break
+		}
+	}
+	return nil
+}
+
+func readVarInt(conn net.Conn, value *int) error {
+	var result int
+	var shift uint
+	for {
+		var b byte
+		if err := readByte(conn, &b); err != nil {
+			return err
+		}
+		result |= int(b&0x7F) << shift
+		shift += 7
+		if b&0x80 == 0 {
+			break
+		}
+	}
+	*value = result
+	return nil
+}
+
+func readHandshakePacket(conn net.Conn, packet *HandshakePacket) error {
+	if err := readVarInt(conn, &packet.ProtocolVersion); err != nil {
+
+	}
+	return nil
+}