TradeTrek/client.go

package main

import (
	"bytes"
	"errors"
	"fmt"
	"net"
	"os"
	"time"
)

type Client struct {
	server      *Server
	conn        net.Conn
	Ip          string
	Line        string
	Prompt      string
	PromptWLine bool
}

func NewClient(server *Server, conn net.Conn) *Client {
	ip := conn.RemoteAddr().String()
	c := &Client{
		server:      server,
		conn:        conn,
		Ip:          ip,
		Line:        "",
		Prompt:      "Login: ",
		PromptWLine: true,
	}
	c.Write("\xff\xfb\x01\xff\xfb\x03\xff\xfd\x10")
	Drain(c.conn, 3)
	go c.reader()
	c.Write("Login: ")
	c.InsertWrite("Trade Trek\r\n")
	c.InsertWrite("v1.0  Apollo@21:1/236\r\n\r\n")
	return c
}

func (c *Client) Write(text string) {
	c.conn.Write([]byte(text))
}

var clearLine = bytes.Repeat([]byte("\b \b"), 500)

func (c *Client) InsertWrite(text string) {
	c.conn.Write(clearLine)
	c.Write(text)
	if len(c.Prompt) != 0 {
		c.Write(c.Prompt)
		if c.PromptWLine {
			c.Write(c.Line)
		}
	}
}

func (c *Client) reader() {
	var (
		buf  []byte = make([]byte, 1024) // 1kb
		read int
		err  error
	)
	for {
		c.conn.SetReadDeadline(time.Now().Add(time.Duration(200) * time.Millisecond))
		read, err = c.conn.Read(buf)
		if err != nil {
			if errors.Is(err, net.ErrClosed) || errors.Is(err, os.ErrClosed) {
				return
			} else if errors.Is(err, os.ErrDeadlineExceeded) {
				if read != 0 {
					c.process(string(buf[0:read]))
				}
				continue
			} else {
				fmt.Printf("%s ERR> %v", c.Ip, err)
				continue
			}
		}
		if read != 0 {
			c.process(string(buf[0:read]))
		}
	}
}

func (c *Client) process(input string) {
	// Process the input as far as ENTER/RETURN and keys being pressed
	// This will require a state machine to track where the client is (Login, Password, Sitting in their ship, Accessing computer, etc)

	// For now we'll just echo it back
	c.Write(input)
}