// tcp_c1 的服务端
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <string.h> // bzero
#include <stdlib.h> // atoi

int main(int argc, char const *argv[])
{
    if (argc != 2)
    {
        printf("usage: %s port\n", argv[0]);
        return 1;
    }

    // TCP 的 socket 套接字类型 SOCK_STREAM
    int sock_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (sock_fd < 0)
    {
        perror("socket");
        return 1;
    }

    // 设置绑定：绑定服务器的IP和端口号
    struct sockaddr_in server_addr;
    bzero(&server_addr, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    server_addr.sin_port = htons(atoi(argv[1]));

    bind(sock_fd, (struct sockaddr *)&server_addr, sizeof(server_addr));

    // 创建监听队列
    if (listen(sock_fd, 50) == -1)
    {
        perror("listen");
    }

    // 接收客户端的连接
    struct sockaddr_in client_addr;
    bzero(&client_addr, sizeof(client_addr));
    socklen_t client_addr_len = sizeof(client_addr);

    // 阻塞到有客户端连接为止
    int client_fd = accept(sock_fd, (struct sockaddr *)&client_addr, &client_addr_len);

    // 客户端 ip
    char client_ip[16] = "";
    inet_ntop(AF_INET, &client_addr.sin_addr.s_addr, client_ip, 16);

    printf("%s(%d) 连接成功\n", client_ip, ntohs(client_addr.sin_port));

    while (1)
    {
        // 接受（读取客户端数据）
        char buf[128] = "";
        ssize_t recv_len = read(client_fd, buf, 128); // 用 recv 也可以
        // ssize_t recv_len = recv(client_fd, buf, 128, 0);

        if (recv_len > 0)
        {
            printf("%s say: %s\n", client_ip, buf);
        }

        if (strncmp(buf, "bye", 3) == 0)
        {
            break;
        }

        memset(buf, 0, 128);
        scanf("%s", buf);
        // if (send(client_fd, buf, strlen(buf) + 1, 0) != -1) // 用 send 也可以
        if (write(client_fd, buf, strlen(buf) + 1) != -1) // 用 send 也可以
        {
            printf("发送数据 OK\n");
        }
    }

    close(client_fd);
    close(sock_fd);
    printf("----over----\n");

    return 0;
}