/*********************************************************************************
 *      Copyright:  (C) 2020 LingYun IoT System Studio
 *                  All rights reserved.
 *
 *       Filename:  tlv_server.c
 *    Description:  This is a socket server program to receive RPi's temperature 
 *                  from socket client and save it in sqlite database.
 *                 
 *        Version:  1.0.0(2020年04月14日)
 *         Author:  Guo Wenxue <guowenxue@gmail.com>
 *      ChangeLog:  1, Release initial version on "2020年04月14日 00时52分56秒"
 *                 
 ********************************************************************************/
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <getopt.h>
#include <libgen.h>

#include "logger.h"
#include "proc.h"
#include "socket.h"

#define PROG_VERSION     "1.0.0"

#define DEF_LOG_FILE     "tlv_server.log"
#define DEF_LISTEN_IP    "0.0.0.0"
#define DEF_LISTEN_PORT  10086

#define MAX_EVENTS       512

static void banner(void)
{
    printf("Version %s build on %s %s\n", PROG_VERSION, __DATE__, __TIME__); 
    printf("Copyright (C) 2020 LingYun IoT System Studio.\n\n");

    return ;
}

static void program_usage(const char *progname)
{
    printf("Usage: %s [OPTION]...\n", progname);
    printf("This program receive RPi's temperature from socket client and save it in sqlite database.\n");

    printf("\nMandatory arguments to long options are mandatory for short options too:\n");
    printf(" -d[debug   ]  Running in debug mode\n");
    printf(" -l[level   ]  Set the log level as [0..%d]\n", LOG_LEVEL_MAX-1); 
    printf(" -h[help    ]  Display this help information\n"); 
    printf(" -v[version ]  Display the program version\n");
    printf("\n");

    banner();
    return ;
}

int main (int argc, char *argv[])
{ 
    int                   opt; 
    int                   i = 0; 
    int                   rv = 0; 
    int                   debug = 0;
    int                   port = DEF_LISTEN_PORT;

    char                  pid_file[64] = { 0 }; /* The file used to record the PID */
    const char           *progname=NULL;

    int                   log_level = LOG_LEVEL_NRML;
    char                 *log_file = DEF_LOG_FILE;
    logger_t              logger;

    socket_t              sock;
    int                   epollfd;
    int                   connfd;
    int                   nfds;
    struct epoll_event    event_array[MAX_EVENTS];

    char                  buf[1024];

    struct option long_options[] = { 
        {"port", required_argument, NULL, 'p'}, 
        {"debug", no_argument, NULL, 'd'}, 
        {"level", required_argument, NULL, 'l'}, 
        {"version", no_argument, NULL, 'v'}, 
        {"help", no_argument, NULL, 'h'}, 
        {NULL, 0, NULL, 0}
    };

    memset(&logger, 0, sizeof(logger));
    memset(&sock, 0, sizeof(sock));

    progname = basename(argv[0]); /* get program name */

    /* parser the command line parameters */ 
    while ((opt = getopt_long(argc, argv, "p:dl:vh", long_options, NULL)) != -1) 
    { 
        switch (opt) 
        {
            case 'p': /* listen port  */
                port = atoi(optarg); 
                break;

            case 'd': /* set debug running */
                debug = 1;
                log_level= LOG_LEVEL_DEBUG;
                log_file = NULL;  /* use standard output */
                break;

            case 'l': /* set the log level */
                i = atoi(optarg); 
                log_level = i>LOG_LEVEL_MAX ? LOG_LEVEL_MAX-1 : i; 
                logger.flag |= FLAG_LOGGER_LEVEL_OPT; 
                break; 

            case 'v':  /* print software version */
                banner();
                return EXIT_SUCCESS; 

            case 'h':  /* print help information */
                program_usage(progname);
                return 0; 

            default: 
                break; 
        } 
    }

    if( port <= 0 )
    {
        printf("ERROR: no listen port specified, refer to program usage\n\n");
        program_usage(progname);
    }

    /* check program already running or not, if already running then exit, or set running as daemon */
    snprintf(pid_file, sizeof(pid_file), "/var/run/%s.pid", progname);
    if( !debug )
    {
        if( check_daemon_running(pid_file) )
        {
            printf("Programe already running, exit now.\n");
            return -1;
        }

        set_daemon_running(pid_file);
    }

    /* initial and open logger system */
    if( logger_init(&logger, log_file, log_level, 512)<0 || logger_open()<0 )
    {
        printf("ERROR: Initialise logger system failure\n");
        return -1;
    }

    /* install signal proc handler */
    install_proc_signal();

    log_nrml("TLV server program start running\n");

    /* set open file description number to max */
    set_socket_rlimit();

    /* initial listen socket  */
    if( socket_listen(&sock, DEF_LISTEN_IP, port) < 0 )
    {
        log_err("create listen socket failure\n");
        return -2;
    }

    /* create epoll and put listen socket into it  */
    if( (epollfd=epoll_init(MAX_EVENTS, sock.fd)) < 0 )
    {
        log_err("initial epoll for listen socket failure\n");
        return -2;
    }

    /* g_signal.stop defined in proc.c, and will be set when catch stop signal */
    while( !g_signal.stop )
    {
        /* epoll wailt and program will blocked here */ 
        nfds = epoll_wait(epollfd, event_array, MAX_EVENTS, -1 /* never timeout */);
        if( nfds <= 0 )
        {
            log_err("epoll_wait failure or timeout: %s\n", strerror(errno));
            continue;
        }

        /* nfds>0 is the active events count */ 
        for(i=0; i<nfds; i++)
        {
            /* epoll get error  */
            if ( (event_array[i].events&EPOLLERR) || (event_array[i].events&EPOLLHUP) )
            {
                log_err("epoll_wait get error on fd[%d]: %s\n", event_array[i].data.fd, strerror(errno));
                epoll_del(epollfd, event_array[i].data.fd);
                close(event_array[i].data.fd);
                continue;
            }

            /* listen socket get event means new client start connect now */ 
            if( event_array[i].data.fd == sock.fd )
            {
                /* accept new client socket  */
                if( (connfd=accept(sock.fd, (struct sockaddr *)NULL, NULL)) < 0)
                {
                    log_nrml("accept new client failure: %s\n", strerror(errno));
                    continue;
                }
                log_info("accept new client socket[%d]\n", connfd);

                /* add new client socket into epoll  */
                if( epoll_add(epollfd, connfd) < 0 )
                {
                    close(connfd);
                    log_err("epoll add client socket failure, rv=%d\n", rv);
                }
                log_dbg("epoll add new client socket[%d] ok.\n", connfd); 
            }
            /* already connected client socket get data arrive  */
            else 
            {
                rv=read(event_array[i].data.fd, buf, sizeof(buf)); 
                if( rv <= 0 )
                {
                    printf("socket[%d] read failure [%s] or disconncet, close and remove now.\n", 
                            event_array[i].data.fd, strerror(errno));

                    epoll_del(epollfd, event_array[i].data.fd);
                    close( event_array[i].data.fd );
                    continue;
                }
                else
                {
                    log_dbg("socket[%d] receive %d bytes data\n", event_array[i].data.fd, rv); 
                    logger_dump(LOG_LEVEL_INFO, buf, rv);
                }
            }
        }

        sleep(1);
    }

    logger_term();

    return 0;
}