/*********************************************************************************
 *      Copyright:  (C) 2012 Guo Wenxue<Email:guowenxue@gmail.com QQ:281143292>
 *                  All rights reserved.
 *
 *       Filename:  date_time_server.c
 *    Description:  This is a sample socket server demo program.
 *                 
 *        Version:  1.0.0(06/08/2012~)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "06/08/2012 02:50:51 PM"
 *                 
 ********************************************************************************/

/* Some Unix Program Standard head file  */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include <getopt.h> /*  getopt_long */
#include <libgen.h> /*  getopt_long */

/* Socket Program head file */
#include <sys/types.h>   
#include <sys/socket.h>
#include <netinet/in.h> /* sockaddr_in{} and other Internet define */

/* strerror(), perror(), errno head file*/
#include <errno.h>
#include <time.h>


#define LISTENQ                                1024 /* 2nd argument to listen () */

#define DEF_USER                               "lingyun"
#define DEF_PASSWD                             "www.iot-yun.com"


void *socket_client_worker(void *arg);


void print_usage(char *progname)
{ 
    printf("Usage: %s [OPTION]...\n", progname);
    
    printf(" %s is a socket server program, which used to verify client and echo back string from it\n", progname); 
    printf("\nMandatory arguments to long options are mandatory for short options too:\n"); 
    
    printf(" -b[daemon ]  set program running on background\n");
    printf(" -p[port    ]  Socket server port address\n");
    printf(" -h[help    ]  Display this help information\n");
    

    printf("\nExample: %s -b -p 8900\n", progname);
    return ;
}


int main(int argc, char **argv)
{
    int                       listenfd, connfd;
    struct sockaddr_in        servaddr;
    int                       serv_port = 0;
    int                       daemon_run = 0;
    char                     *progname = NULL;
    pthread_t                 tid;
    int                       opt;
    int                       on=1;


    struct option             long_options[] = 
    {   
        {"daemon", no_argument, NULL, 'b'},
        {"port", required_argument, NULL, 'p'},
        {"help", no_argument, NULL, 'h'},
        {NULL, 0, NULL, 0}
    };  

    progname = basename(argv[0]);

    /*  Parser the command line parameters */
    while ((opt = getopt_long(argc, argv, "bp:h", long_options, NULL)) != -1) 
    {   
        switch (opt)
        {   
            case 'b':
                daemon_run=1;
                break;

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

            case 'h':  /*  Get help information */
                print_usage(progname);
                return EXIT_SUCCESS;

            default:
                break;
        }   
    }   

    if(0==serv_port) 
    {   
        print_usage(progname);
        return -1; 
    }

    /* set program running on background */
    if( daemon_run )
    {
        daemon(0, 0);
    }

    /*
     * Open an IPV4(AF_INET) TCP(SOCK_STREAM) Socket File Description(listenfd), UDP socket 
     * should use SOCK_DGRAM,We can use linux command "man socket" to see this function manual
     */
    if ( (listenfd = socket(AF_INET, SOCK_STREAM, 0)) < 0)
    {
        /* strerror() is the 1st way to display the failure reason, argument 
         * errno is a globle variable defined in <errno.h>, we can use linux command 
         * "man strerror" to see this function manual*/
        printf("Use socket() to create a TCP socket failure: %s\n", strerror(errno));
        return -1;
    }

    /* Set socket port reuseable  */
    setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

    /* Now we set the Server Information, include IPV4 or IPV6, Listen IP address and Port */
    memset(&servaddr, 0, sizeof(servaddr));
    servaddr.sin_family = AF_INET;   /* Set it as IPV4 protocal */
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);  /* Listen all the local IP address */
    servaddr.sin_port = htons(serv_port); /*  daytime server port */

    /*
     * When a socket is created with socket(2), it exists in a name space (address family) but 
     * has no address assigned to it. bind() assigns the address specified to by addr to the 
     * socket referred to by the file descriptor listenfd. We can use Linux command "man 2 bind" 
     * to see this function manual.
     */
    if(bind(listenfd, (struct sockaddr *) &servaddr, sizeof(servaddr)) < 0)
    {
        printf("Use bind() to bind the TCP socket failure: %s\n", strerror(errno));
        goto CleanUp;
    }

    /*
     * listen() marks the socket referred to by listenfd as a passive socket, that is, as a socket 
     * that will be used to accept incoming connection requests using accept(2). We can use Linux
     * command "man listen" to see this function manual.
     */
    if(listen(listenfd, LISTENQ) < 0)
    {
        printf("Use bind() to bind the TCP socket failure: %s\n", strerror(errno));
        goto CleanUp;
    }
    printf("%s server start to listen port %d\n", argv[0],serv_port);


    for ( ; ; ) 
    {
        /*
         * The accept() system call is used with connection-based socket types (SOCK_STREAM, SOCK_SEQPACKET).
         * It extracts the first connection request on the queue of pending connections for the listening 
         * socket linstenfd, creates a new connected socket(connfd), and returns a new file descriptor referring 
         * to that socket. The newly created socket is not in the listening state. The original socket 
         * listenfd is unaffected by this call.
         */

        if( (connfd=accept(listenfd, (struct sockaddr *)NULL, NULL)) > 0)
        {
            pthread_create(&tid, NULL, socket_client_worker, (void *)connfd);
        }
    }

CleanUp:
    close(listenfd);  /* We must close socket File Description when program exit*/
    return 0;
}

static inline msleep(unsigned long ms) 
{
    struct timeval       tv; 

    tv.tv_sec = ms/1000;
    tv.tv_usec = (ms%1000)*1000; 
    
    select(0, NULL, NULL, NULL, &tv);
}


char      *fail_str[3]={"Verify user account get wrong format",
                        "Verify user account get wrong username",
                        "Verify user account get wrong password"};
int verify_user_logon(char *buf)
{
    char                *ptr = NULL;

    if( !(ptr=strchr(buf, ':')) )
    {
        return 1;
    }

    if( strncmp(buf, DEF_USER, strlen(DEF_USER)) )
    {
        return 2;
    }

    if( strncmp(ptr+1, DEF_PASSWD, strlen(DEF_PASSWD)) )
    {
        return 3;
    }

    return 0;
}

void *socket_client_worker(void *arg)
{
    int            client_fd;
    char           buf[512];
    int            rv;

    if( !arg )
    {
        printf("Invalid arg\n");
        return NULL;
    }

    client_fd = (int) arg;

#ifdef CONFIG_VERIFY_USER
    memset(buf, 0, sizeof(buf));
    if( (rv=read(client_fd, buf, sizeof(buf))) <= 0)
    {
        printf("socket disconncet or read get error\n");
        goto CleanUp;
    }

    if( 0 != (rv=verify_user_logon(buf)) )
    {
        printf("client logon account [%s] invalid, disconncet it now\n", buf);
        write(client_fd, fail_str[rv-1], strlen(fail_str[rv-1]));
        goto CleanUp;
    }

    write(client_fd, "passed", 6);
#endif

    while(1)
    {
        memset(buf, 0, sizeof(buf));
        if( (rv=read(client_fd, buf, sizeof(buf))) <= 0)
        {
            printf("socket disconncet or read get error\n");
            goto CleanUp;
        }

        /* echo the data from client back  */
        printf("socket[%d] read get %d bytes data and will echo it back\n", client_fd, rv);
        write(client_fd, buf, rv);
    }


CleanUp:
    printf("Thread worker for socket[%d] exit.\n", client_fd);
    msleep(500);
    close(client_fd);
}