/*********************************************************************************
 *      Copyright:  (C) 2018 LingYun IoT Studio
 *                  All rights reserved.
 *
 *       Filename:  sockudp_client.c
 *    Description:  This file is UDP socket client example source code.
 *
 *        Version:  1.0.0(10/23/2018)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2018-10-23 01:38:08 PM"
 *
 ********************************************************************************/
#include <stdio.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>

#define SERVER_IP          "127.0.0.1"
#define SERVER_PORT        8890


int main(int argc, char **argv)
{
    int                     sockfd = -1;
    int                     rv = -1;
    char                    buf[1024];
    struct sockaddr_in      serv_addr;
    socklen_t               addrlen = sizeof(serv_addr);
    float                   temp;

    /* create UDP socket */
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if(sockfd < 0)
    {
        printf("create socket failure: %s\n", strerror(errno));
        return -1;
    }

    /* set socket server information  */
    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(SERVER_PORT);
    inet_aton( SERVER_IP, &serv_addr.sin_addr );

    while(1)
    {
        /* send message to socket server */
        strncpy(buf, "Hello, LingYun IoT socket server!", sizeof(buf));
        if( sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr *)&serv_addr, addrlen) < 0 )
        {
            printf("Write data to server [%s:%d] failure: %s\n", SERVER_IP, SERVER_PORT, strerror(errno));
            break;
        }
        printf("Send message to socket server okay\n");

        /* receive message from socket server */
        memset(buf, 0, sizeof(buf));
        printf("Wating reply from socket server...\n");
        rv = recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr *)&serv_addr, &addrlen);
        if(rv < 0)
        {
            printf("Read data from server failure: %s\n", strerror(errno));
            break;
        }
        printf("Receive [%d] bytes data from server: %s", rv, buf);
        printf("\n");

        sleep(3);
    }

    close(sockfd);
    return 0;
}