/*********************************************************************************
 *      Copyright:  (C) 2018 LingYun IoT Studio
 *                  All rights reserved.
 *
 *       Filename:  socket_server.c
 *    Description:  This file is socket server sample source code, it will echo back
 *                  the receive data from client.
 *                 
 *        Version:  1.0.0(10/23/2018)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2017-10-23 01:41:05 PM"
 *                 
 ********************************************************************************/

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

#define DEF_LISTEN_PORT      8060
#define BACKLOG              13

int main(int argc, char **argv)
{
    int                     rv = -1;
    int                     listen_fd,  client_fd = -1;
    struct sockaddr_in      serv_addr;             
    struct sockaddr_in      cli_addr;
    socklen_t               cliaddr_len;
    char                    buf[1024]; 
    int                     port = DEF_LISTEN_PORT;
    int                     reuse = 1;

    printf("You can use '%s [port]' to change default port[%d].\n", argv[0], DEF_LISTEN_PORT);

    if( 2== argc )
    {
        port = atoi(argv[1]);
    }

    listen_fd = socket(AF_INET, SOCK_STREAM, 0);
    if(listen_fd < 0 )
    {
        printf("create socket failure: %s\n", strerror(errno));
        return -1;
    }
    printf("socket create fd[%d]\n", listen_fd);

    setsockopt(listen_fd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));

    memset(&serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;        
    serv_addr.sin_port = htons(port);
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    if( bind(listen_fd, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0 )
    {
        printf("create socket failure: %s\n", strerror(errno));
        return -2;
    }
    printf("socket[%d] bind on port[%d] for all IP address ok\n", listen_fd, port);

    listen(listen_fd, BACKLOG); 
    
    while(1)   
    {
        printf("\nStart waiting and accept new client connect...\n", listen_fd);
        client_fd = accept(listen_fd, (struct sockaddr*)&cli_addr, &cliaddr_len);
        if(client_fd < 0)
        {
            printf("accept new socket failure: %s\n", strerror(errno));
            return -2;
        }
        printf("Accept new client[%s:%d] with fd [%d]\n", inet_ntoa(cli_addr.sin_addr), ntohs(cli_addr.sin_port), client_fd);


        memset(buf, 0, sizeof(buf));        
        if( (rv=read(client_fd, buf, sizeof(buf))) < 0)
        {
            printf("Read data from client socket[%d] failure: %s\n", client_fd, strerror(errno));
            close(client_fd);
            continue; 
        } 
        else if( rv == 0 )
        {
            printf("client socket[%d] disconnected\n", client_fd);
            close(client_fd);
            continue;
        }
        printf("read %d bytes data from client[%d] and echo it back: '%s'\n", rv, client_fd, buf);


        if( write(client_fd, buf, rv) < 0 )
        {
            printf("Write %d bytes data back to client[%d] failure: %s\n", rv, client_fd, strerror(errno));
            close(client_fd);
        }
	
        nanosleep(1000);
        close(client_fd); 
    } 

    close(listen_fd);
}