feat: add handler for communication between client and server

internal/lib/protocol.go

@@ -0,0 +1,66 @@
+/*
+Copyright © 2024 tux <0xtux@pm.me>
+*/
+
+package lib
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+)
+
+type Message struct {
+	CMD string
+	ARG string
+}
+
+type ProtocolHandler struct {
+	reader *bufio.Reader
+	writer *bufio.Writer
+}
+
+func InitProtocolHandler(conn net.Conn) *ProtocolHandler {
+	return &ProtocolHandler{
+		reader: bufio.NewReader(conn),
+		writer: bufio.NewWriter(conn),
+	}
+}
+
+func (p *ProtocolHandler) ReadMessage() (*Message, error) {
+	data, err := p.reader.ReadString('\n')
+	if err != nil {
+		return nil, err
+	}
+
+	cmd, arg, err := p.parseMessage(data)
+	if err != nil {
+		return nil, errors.New("can't parse data")
+	}
+
+	return &Message{
+		CMD: cmd,
+		ARG: arg,
+	}, nil
+}
+
+func (p *ProtocolHandler) WriteMessage(m *Message) error {
+	_, err := p.writer.WriteString(fmt.Sprintf("%s %s\n", m.CMD, m.ARG))
+	if err != nil {
+		return err
+	}
+	return p.writer.Flush()
+}
+
+func (p *ProtocolHandler) parseMessage(data string) (string, string, error) {
+	data = strings.TrimSpace(data)
+	d := strings.Fields(data)
+
+	if len(d) != 2 {
+		return "", "", errors.New("invalid command")
+	}
+
+	return d[0], d[1], nil
+}