/*********************************************************************************
 *      Copyright:  (C) 2025 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  socket.c
 *    Description:  This file is TCP socket client example program.
 *
 *        Version:  1.0.0(10/20/2025)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "10/20/2025 09:48:51 PM"
 *
 ********************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <getopt.h>

void print_usage(char *progname)
{
    printf("%s usage: \n", progname);
    printf("  -i(--ipaddr): sepcify server IP address\n");
    printf("  -p(--port): sepcify server port.\n");
    printf("  -h(--Help): print this help information.\n");

    return ;
}

int main(int argc, char **argv)
{
    int                     conn_fd = -1;
    int                     rv = -1;
    char                    buf[1024];
    char                   *servip = "127.0.0.1";
    int                     port = 0;
    struct sockaddr_in      serv_addr;

    int                     ch;
    struct option           opts[] = {
        {"ipaddr", required_argument, NULL, 'i'},
        {"port", required_argument, NULL, 'p'},
        {"help", no_argument, NULL, 'h'},
        {NULL, 0, NULL, 0}
    };

    /* parser command line input arguments */
    while( (ch=getopt_long(argc, argv, "i:p:h", opts, NULL)) != -1 )
    {
        switch(ch)
        {
            case 'i':
                servip=optarg;
                break;

            case 'p':
                port=atoi(optarg);
                break;

            case 'h':
                print_usage(argv[0]);
                return 0;
        }

    }

    /* socket client must specify server IP address and port */
    if( !servip || !port )
    {
        print_usage(argv[0]);
        return 1;
    }

    /* create TCP socket */
    conn_fd = socket(AF_INET, SOCK_STREAM, 0);
    if(conn_fd < 0)
    {
        printf("create socket failure: %s\n", strerror(errno));
        return 2;
    }

    /* set server IP address and port into $server_addr */
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(port);
    inet_aton( servip, &serv_addr.sin_addr );

    /* connect to socket server */
    if( connect(conn_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr))  < 0)
    {
        printf("connect to server [%s:%d] failure: %s\n", servip, port, strerror(errno));
        return 3;
    }

    while(1)
    {
        /* send message to socket server */
        strncpy(buf, "Hello, LingYun IoT socket server!\n", sizeof(buf));
        if( write(conn_fd, buf, strlen(buf)) < 0 )
        {
            printf("Write data to server [%s:%d] failure: %s\n", servip, port, strerror(errno));
            goto cleanup;
        }
        printf("Send message to socket server okay\n");

        /* receive message from socket server */
        printf("Wating reply from socket server...\n");
        memset(buf, 0, sizeof(buf));
        rv = read(conn_fd, buf, sizeof(buf));
        if(rv < 0)
        {
            printf("Read data from server failure: %s\n", strerror(errno));
            goto cleanup;
        }
        else if( 0 == rv )
        {
            printf("Client connect to server get disconnected\n");
            goto cleanup;
        }
        printf("Receive [%d] bytes data from server: %s", rv, buf);
        printf("\n");

        sleep(3);
    }

cleanup:
    close(conn_fd);
    return 0;
}