#聊天室小项目—golang服务端

package main

import (

"fmt"
"net"
"strings"
"time"

)

type User struct {

id   string
name string
msg  chan string

}

//搞一个key-value变量(map结构),并make出来空间

var allUsers = make(map[string]User)

//全局管道，进行广播

var message = make(chan string, 10)

func main() {

listener, err := net.Listen("tcp", "172.16.76.129:8080")
if err != nil {
    fmt.Println("服务器端提示：listen err:", err)
    return
}
//监听广播管道
go broadcast()
//持续监听新用户连接请求
for {
    fmt.Println("服务器端提示：监听中...")
    conn, err := listener.Accept()
    if err != nil {
        fmt.Println("conn err:", err)
    }
    fmt.Println("服务器端提示：建立连接成功...")
    //握手成功
    go handler(conn)
}

}

//连接完成，处理业务

func handler(conn net.Conn) {

fmt.Println("服务器端提示：handle...")
//把所有user写进map
clientAddr := conn.RemoteAddr().String()
newuser := User{
    id:   clientAddr,
    name: clientAddr,
    msg:  make(chan string),
}
allUsers[newuser.id] = newuser
//写回客户端
go writebackToClient(&newuser, conn)
//退出账户
var isQuit = make(chan bool)
var timeReset = make(chan bool)
go quit(isQuit, timeReset, &newuser, conn)
//上线广播
msginfo := fmt.Sprintf("id:%s,name:%s 上线了...\n", newuser.id, newuser.name)
message <- msginfo
//----------  处理具体业务    ------------
//持续接收客户端数据
for {
    buf := make([]byte, 1024)
    //读取客户端数据到buf
    count, err := conn.Read(buf)
    //用户crtl+c退出
    if count == 0 {
        isQuit <- true
        return
    }
    if err != nil {
        fmt.Printf("服务器端提示：conn.Read err:%s,count:%d", err, count)
        return
    }
    //所有用户信息整理成一个字符串，并用回车换行
    var whoUser []string
    for _, user := range allUsers {
        userinfo := fmt.Sprintf("id:%s,name:%s", user.id, user.name)
        whoUser = append(whoUser, userinfo)
    }
    r := strings.Join(whoUser, "\n")
    //查询所有用户业务
    userInput := string(buf[:count-1])
    if len(userInput) == 5 && (userInput == "[who]" || userInput == "[WHO]") {
        newuser.msg <- (r + "\n")
        //修改名字
    } else if len(userInput) > 8 && (userInput[:8] == "[rename]") {
        newuser.name = strings.Split(userInput, "]")[1]
        allUsers[newuser.id] = newuser
        newuser.msg <- "[rename] successfully!\n"
    } else {
        message <- (userInput + "\n")
    }
    //重置计时器
    timeReset <- true
}
//----------  处理具体业务    ------------

}

//广播消息

func broadcast() {

fmt.Println("服务器端提示：广播启动成功...")
defer fmt.Println("服务器端提示：广播异常退出...")
for {
    info := <-message
    for _, user := range allUsers {
        user.msg <- info
    }
}

}

//写回客户端

func writebackToClient(user *User, conn net.Conn) {

fmt.Println("服务器端提示：writebackToClient启动...")
for {
    data := <-user.msg //必须加上 <-
    conn.Write([]byte(data))
}
// for data := range user.msg { //range下不用 <-
//  conn.Write([]byte(data))
// }

}

//退出账户

func quit(isQuit, timeReset <-chan bool, user *User, conn net.Conn) {

fmt.Println("服务器端提示：等待执行退出账户...")
defer fmt.Println("服务器端提示：用户退出成功！")
// if <-isQuit {
//  message <- fmt.Sprintf("username:%s退出\n", user.name)
//  delete(allUsers, user.id)
//  conn.Close()
//  return
// }
for {
    select {
    case <-isQuit:
        message <- fmt.Sprintf("username:%s主动退出", user.name)
        delete(allUsers, user.id)
        conn.Close()
        return
    case <-time.After(10 * time.Second):
        message <- fmt.Sprintf("username:%s超时退出", user.name)
        delete(allUsers, user.id)
        conn.Close()
        return
    case <-timeReset:
        fmt.Printf("客户端提示：uesrname:%s重置计时器成功\n", user.name)
    }
}

}