package main

import (
    "fmt"
    "net"
    "sync"
    "time"
)

type Client struct {
    conn     net.Conn
    username string
}

type ChatServer struct {
    clients map[*Client]bool
    lock    sync.Mutex
}

func NewChatServer() *ChatServer {
    return &ChatServer{
        clients: make(map[*Client]bool),
    }
}

func (server *ChatServer) addClient(client *Client) {
    server.lock.Lock()
    defer server.lock.Unlock()
    server.clients[client] = true
}

func (server *ChatServer) removeClient(client *Client) {
    server.lock.Lock()
    defer server.lock.Unlock()
    delete(server.clients, client)
}

func (server *ChatServer) broadcastMessage(message string, sender *Client) {
    server.lock.Lock()
    defer server.lock.Unlock()

    for client := range server.clients {
        if client != sender {
            _, err := client.conn.Write([]byte(message))
            if err != nil {
                fmt.Println("發(fā)送消息失敗:", err)
            }
        }
    }
}

func handleConnection(conn net.Conn, server *ChatServer) {
    defer conn.Close()
    var client *Client

    fmt.Println("新的客戶端連接:", conn.RemoteAddr())

    // 為每個(gè)客戶端創(chuàng)建唯一的連接對(duì)象
    client = &Client{conn: conn}

    // 發(fā)送歡迎信息
    conn.Write([]byte("歡迎加入聊天室! 請(qǐng)輸入你的昵稱:\n"))

    // 獲取用戶名
    var username string
    fmt.Fscan(conn, &username)
    client.username = username
    server.addClient(client)

    // 向所有客戶端廣播消息，通知新用戶加入
    server.broadcastMessage(client.username+" 加入了聊天室\n", client)

    // 處理客戶端消息
    go func() {
        reader := make([]byte, 1024)
        for {
            length, err := conn.Read(reader)
            if err != nil {
                fmt.Println("客戶端斷開:", client.username)
                server.removeClient(client)
                break
            }
            message := fmt.Sprintf("%s: %s", client.username, string(reader[:length]))
            server.broadcastMessage(message+"\n", client)
        }
    }()

    // 保持主線程
    for {
        time.Sleep(time.Second * 1)
    }
}

func main() {
    server := NewChatServer()

    // 啟動(dòng)服務(wù)器并監(jiān)聽端口
    listener, err := net.Listen("tcp", ":8080")
    if err != nil {
        fmt.Println("無法啟動(dòng)服務(wù)器:", err)
        return
    }
    defer listener.Close()

    fmt.Println("聊天室服務(wù)端已啟動(dòng)，監(jiān)聽端口 8080...")

    for {
        conn, err := listener.Accept()
        if err != nil {
            fmt.Println("連接錯(cuò)誤:", err)
            continue
        }

        go handleConnection(conn, server)
    }
}

package main

import (
    "fmt"
    "net"
    "os"
    "bufio"
    "strings"
)

func main() {
    fmt.Print("請(qǐng)輸入聊天室服務(wù)器的IP地址: ")
    var serverIP string
    fmt.Scanln(&serverIP)

    conn, err := net.Dial("tcp", serverIP+":8080")
    if err != nil {
        fmt.Println("連接服務(wù)器失敗:", err)
        return
    }
    defer conn.Close()

    fmt.Print("請(qǐng)輸入你的昵稱: ")
    var username string
    fmt.Scanln(&username)

    conn.Write([]byte(username + "\n"))

    // 讀取服務(wù)器的消息并顯示
    go func() {
        reader := bufio.NewReader(conn)
        for {
            message, _ := reader.ReadString('\n')
            fmt.Print(message)
        }
    }()

    // 輸入消息并發(fā)送到服務(wù)器
    for {
        fmt.Print("請(qǐng)輸入消息: ")
        reader := bufio.NewReader(os.Stdin)
        message, _ := reader.ReadString('\n')
        message = strings.TrimSpace(message)

        if message == "exit" {
            fmt.Println("退出聊天室...")
            break
        }

        conn.Write([]byte(message + "\n"))
    }
}

go run server.go

go run client.go

go func() {
    reader := make([]byte, 1024)
    for {
        length, err := conn.Read(reader)
        if err != nil {
            fmt.Println("客戶端斷開:", client.username)
            server.removeClient(client)
            break
        }
        message := fmt.Sprintf("%s: %s", client.username, string(reader[:length]))
        server.broadcastMessage(message+"\n", client)
    }
}()

func (server *ChatServer) broadcastMessage(message string, sender *Client) {
    server.lock.Lock()
    defer server.lock.Unlock()

    for client := range server.clients {
        if client != sender {
            _, err := client.conn.Write([]byte(message))
            if err != nil {
                fmt.Println("發(fā)送消息失敗:", err)
            }
        }
    }
}

server.removeClient(client)