//
// Copyright (c) 2013-2021 Winlin
//
// SPDX-License-Identifier: MIT
//

#include <srs_app_utility.hpp>

#include <sys/types.h>
#include <unistd.h>
#include <ifaddrs.h>
#include <arpa/inet.h>
#include <signal.h>
#include <sys/wait.h>
#include <netdb.h>

#include <stdlib.h>
#include <sys/time.h>
#include <math.h>
#include <map>
#ifdef SRS_OSX
#include <sys/sysctl.h>
#endif
using namespace std;

#include <srs_kernel_log.hpp>
#include <srs_app_config.hpp>
#include <srs_kernel_utility.hpp>
#include <srs_kernel_error.hpp>
#include <srs_protocol_kbps.hpp>
#include <srs_protocol_json.hpp>
#include <srs_kernel_buffer.hpp>
#include <srs_protocol_amf0.hpp>
#include <srs_kernel_utility.hpp>

// the longest time to wait for a process to quit.
#define SRS_PROCESS_QUIT_TIMEOUT_MS 1000

SrsLogLevel srs_get_log_level(string level)
{
    if ("verbose" == level) {
        return SrsLogLevelVerbose;
    } else if ("info" == level) {
        return SrsLogLevelInfo;
    } else if ("trace" == level) {
        return SrsLogLevelTrace;
    } else if ("warn" == level) {
        return SrsLogLevelWarn;
    } else if ("error" == level) {
        return SrsLogLevelError;
    } else {
        return SrsLogLevelDisabled;
    }
}

string srs_path_build_stream(string template_path, string vhost, string app, string stream)
{
    std::string path = template_path;
    
    // variable [vhost]
    path = srs_string_replace(path, "[vhost]", vhost);
    // variable [app]
    path = srs_string_replace(path, "[app]", app);
    // variable [stream]
    path = srs_string_replace(path, "[stream]", stream);
    
    return path;
}

string srs_path_build_timestamp(string template_path)
{
    std::string path = template_path;
    
    
    // date and time substitude
    // clock time
    timeval tv;
    if (gettimeofday(&tv, NULL) == -1) {
        return path;
    }
    
    // to calendar time
    struct tm* tm;
    if (_srs_config->get_utc_time()) {
        if ((tm = gmtime(&tv.tv_sec)) == NULL) {
            return path;
        }
    } else {
        if ((tm = localtime(&tv.tv_sec)) == NULL) {
            return path;
        }
    }
    
    // the buffer to format the date and time.
    char buf[64];
    
    // [2006], replace with current year.
    if (true) {
        snprintf(buf, sizeof(buf), "%04d", 1900 + tm->tm_year);
        path = srs_string_replace(path, "[2006]", buf);
    }
    // [01], replace this const to current month.
    if (true) {
        snprintf(buf, sizeof(buf), "%02d", 1 + tm->tm_mon);
        path = srs_string_replace(path, "[01]", buf);
    }
    // [02], replace this const to current date.
    if (true) {
        snprintf(buf, sizeof(buf), "%02d", tm->tm_mday);
        path = srs_string_replace(path, "[02]", buf);
    }
    // [15], replace this const to current hour.
    if (true) {
        snprintf(buf, sizeof(buf), "%02d", tm->tm_hour);
        path = srs_string_replace(path, "[15]", buf);
    }
    // [04], repleace this const to current minute.
    if (true) {
        snprintf(buf, sizeof(buf), "%02d", tm->tm_min);
        path = srs_string_replace(path, "[04]", buf);
    }
    // [05], repleace this const to current second.
    if (true) {
        snprintf(buf, sizeof(buf), "%02d", tm->tm_sec);
        path = srs_string_replace(path, "[05]", buf);
    }
    // [999], repleace this const to current millisecond.
    if (true) {
        snprintf(buf, sizeof(buf), "%03d", (int)(tv.tv_usec / 1000));
        path = srs_string_replace(path, "[999]", buf);
    }
    // [timestamp],replace this const to current UNIX timestamp in ms.
    if (true) {
        int64_t now_us = ((int64_t)tv.tv_sec) * 1000 * 1000 + (int64_t)tv.tv_usec;
        path = srs_string_replace(path, "[timestamp]", srs_int2str(now_us / 1000));
    }
    
    return path;
}

srs_error_t srs_kill_forced(int& pid)
{
    srs_error_t err = srs_success;
    
    if (pid <= 0) {
        return err;
    }
    
    // first, try kill by SIGTERM.
    if (kill(pid, SIGTERM) < 0) {
        return srs_error_new(ERROR_SYSTEM_KILL, "kill");
    }
    
    // wait to quit.
    srs_trace("send SIGTERM to pid=%d", pid);
    for (int i = 0; i < SRS_PROCESS_QUIT_TIMEOUT_MS / 10; i++) {
        int status = 0;
        pid_t qpid = -1;
        if ((qpid = waitpid(pid, &status, WNOHANG)) < 0) {
            return srs_error_new(ERROR_SYSTEM_KILL, "kill");
        }
        
        // 0 is not quit yet.
        if (qpid == 0) {
            srs_usleep(10 * 1000);
            continue;
        }
        
        // killed, set pid to -1.
        srs_trace("SIGTERM stop process pid=%d ok.", pid);
        pid = -1;
        
        return err;
    }
    
    // then, try kill by SIGKILL.
    if (kill(pid, SIGKILL) < 0) {
        return srs_error_new(ERROR_SYSTEM_KILL, "kill");
    }
    
    // wait for the process to quit.
    // for example, ffmpeg will gracefully quit if signal is:
    //         1) SIGHUP     2) SIGINT     3) SIGQUIT
    // other signals, directly exit(123), for example:
    //        9) SIGKILL    15) SIGTERM
    int status = 0;
    // @remark when we use SIGKILL to kill process, it must be killed,
    //      so we always wait it to quit by infinite loop.
    while (waitpid(pid, &status, 0) < 0) {
        srs_usleep(10 * 1000);
        continue;
    }
    
    srs_trace("SIGKILL stop process pid=%d ok.", pid);
    pid = -1;
    
    return err;
}

static SrsRusage _srs_system_rusage;

SrsRusage::SrsRusage()
{
    ok = false;
    sample_time = 0;
    memset(&r, 0, sizeof(rusage));
}

SrsRusage* srs_get_system_rusage()
{
    return &_srs_system_rusage;
}

void srs_update_system_rusage()
{
    if (getrusage(RUSAGE_SELF, &_srs_system_rusage.r) < 0) {
        srs_warn("getrusage failed, ignore");
        return;
    }
    
    _srs_system_rusage.sample_time = srsu2ms(srs_update_system_time());
    
    _srs_system_rusage.ok = true;
}

static SrsProcSelfStat _srs_system_cpu_self_stat;
static SrsProcSystemStat _srs_system_cpu_system_stat;

SrsProcSelfStat::SrsProcSelfStat()
{
    ok = false;
    sample_time = 0;
    percent = 0;
    
    pid = 0;
    memset(comm, 0, sizeof(comm));
    state = '0';
    ppid = 0;
    pgrp = 0;
    session = 0;
    tty_nr = 0;
    tpgid = 0;
    flags = 0;
    minflt = 0;
    cminflt = 0;
    majflt = 0;
    cmajflt = 0;
    utime = 0;
    stime = 0;
    cutime = 0;
    cstime = 0;
    priority = 0;
    nice = 0;
    num_threads = 0;
    itrealvalue = 0;
    starttime = 0;
    vsize = 0;
    rss = 0;
    rsslim = 0;
    startcode = 0;
    endcode = 0;
    startstack = 0;
    kstkesp = 0;
    kstkeip = 0;
    signal = 0;
    blocked = 0;
    sigignore = 0;
    sigcatch = 0;
    wchan = 0;
    nswap = 0;
    cnswap = 0;
    exit_signal = 0;
    processor = 0;
    rt_priority = 0;
    policy = 0;
    delayacct_blkio_ticks = 0;
    guest_time = 0;
    cguest_time = 0;
}

SrsProcSystemStat::SrsProcSystemStat()
{
    ok = false;
    sample_time = 0;
    percent = 0;
    total_delta = 0;
    user = 0;
    nice = 0;
    sys = 0;
    idle = 0;
    iowait = 0;
    irq = 0;
    softirq = 0;
    steal = 0;
    guest = 0;
}

int64_t SrsProcSystemStat::total()
{
    return user + nice + sys + idle + iowait + irq + softirq + steal + guest;
}

SrsProcSelfStat* srs_get_self_proc_stat()
{
    return &_srs_system_cpu_self_stat;
}

SrsProcSystemStat* srs_get_system_proc_stat()
{
    return &_srs_system_cpu_system_stat;
}

bool get_proc_system_stat(SrsProcSystemStat& r)
{
#ifndef SRS_OSX
    FILE* f = fopen("/proc/stat", "r");
    if (f == NULL) {
        srs_warn("open system cpu stat failed, ignore");
        return false;
    }
    
    static char buf[1024];
    while (fgets(buf, sizeof(buf), f)) {
        if (strncmp(buf, "cpu ", 4) != 0) {
            continue;
        }
        
        // @see: read_stat_cpu() from https://github.com/sysstat/sysstat/blob/master/rd_stats.c#L88
        // @remark, ignore the filed 10 cpu_guest_nice
        sscanf(buf + 5, "%llu %llu %llu %llu %llu %llu %llu %llu %llu\n",
               &r.user,
               &r.nice,
               &r.sys,
               &r.idle,
               &r.iowait,
               &r.irq,
               &r.softirq,
               &r.steal,
               &r.guest);
        
        break;
    }
    
    fclose(f);
#endif

    r.ok = true;
    
    return true;
}

bool get_proc_self_stat(SrsProcSelfStat& r)
{
#ifndef SRS_OSX
    FILE* f = fopen("/proc/self/stat", "r");
    if (f == NULL) {
        srs_warn("open self cpu stat failed, ignore");
        return false;
    }
    
    fscanf(f, "%d %32s %c %d %d %d %d "
           "%d %u %lu %lu %lu %lu "
           "%lu %lu %ld %ld %ld %ld "
           "%ld %ld %llu %lu %ld "
           "%lu %lu %lu %lu %lu "
           "%lu %lu %lu %lu %lu "
           "%lu %lu %lu %d %d "
           "%u %u %llu "
           "%lu %ld",
           &r.pid, r.comm, &r.state, &r.ppid, &r.pgrp, &r.session, &r.tty_nr,
           &r.tpgid, &r.flags, &r.minflt, &r.cminflt, &r.majflt, &r.cmajflt,
           &r.utime, &r.stime, &r.cutime, &r.cstime, &r.priority, &r.nice,
           &r.num_threads, &r.itrealvalue, &r.starttime, &r.vsize, &r.rss,
           &r.rsslim, &r.startcode, &r.endcode, &r.startstack, &r.kstkesp,
           &r.kstkeip, &r.signal, &r.blocked, &r.sigignore, &r.sigcatch,
           &r.wchan, &r.nswap, &r.cnswap, &r.exit_signal, &r.processor,
           &r.rt_priority, &r.policy, &r.delayacct_blkio_ticks,
           &r.guest_time, &r.cguest_time);
    
    fclose(f);
#endif

    r.ok = true;
    
    return true;
}

void srs_update_proc_stat()
{
    // @see: http://stackoverflow.com/questions/7298646/calculating-user-nice-sys-idle-iowait-irq-and-sirq-from-proc-stat/7298711
    // @see https://github.com/ossrs/srs/issues/397
    static int user_hz = 0;
    if (user_hz <= 0) {
        user_hz = (int)sysconf(_SC_CLK_TCK);
        srs_info("USER_HZ=%d", user_hz);
        srs_assert(user_hz > 0);
    }
    
    // system cpu stat
    if (true) {
        SrsProcSystemStat r;
        if (!get_proc_system_stat(r)) {
            return;
        }
        
        r.sample_time = srsu2ms(srs_update_system_time());
        
        // calc usage in percent
        SrsProcSystemStat& o = _srs_system_cpu_system_stat;
        
        // @see: http://blog.csdn.net/nineday/article/details/1928847
        // @see: http://stackoverflow.com/questions/16011677/calculating-cpu-usage-using-proc-files
        if (o.total() > 0) {
            r.total_delta = r.total() - o.total();
        }
        if (r.total_delta > 0) {
            int64_t idle = r.idle - o.idle;
            r.percent = (float)(1 - idle / (double)r.total_delta);
        }
        
        // upate cache.
        _srs_system_cpu_system_stat = r;
    }
    
    // self cpu stat
    if (true) {
        SrsProcSelfStat r;
        if (!get_proc_self_stat(r)) {
            return;
        }
        
        r.sample_time = srsu2ms(srs_update_system_time());
        
        // calc usage in percent
        SrsProcSelfStat& o = _srs_system_cpu_self_stat;
        
        // @see: http://stackoverflow.com/questions/16011677/calculating-cpu-usage-using-proc-files
        int64_t total = r.sample_time - o.sample_time;
        int64_t usage = (r.utime + r.stime) - (o.utime + o.stime);
        if (total > 0) {
            r.percent = (float)(usage * 1000 / (double)total / user_hz);
        }
        
        // upate cache.
        _srs_system_cpu_self_stat = r;
    }
}

SrsDiskStat::SrsDiskStat()
{
    ok = false;
    sample_time = 0;
    in_KBps = out_KBps = 0;
    busy = 0;
    
    pgpgin = 0;
    pgpgout = 0;
    
    rd_ios = rd_merges = 0;
    rd_sectors = 0;
    rd_ticks = 0;
    
    wr_ios = wr_merges = 0;
    wr_sectors = 0;
    wr_ticks = nb_current = ticks = aveq = 0;
}

static SrsDiskStat _srs_disk_stat;

SrsDiskStat* srs_get_disk_stat()
{
    return &_srs_disk_stat;
}

bool srs_get_disk_vmstat_stat(SrsDiskStat& r)
{
#ifndef SRS_OSX
    FILE* f = fopen("/proc/vmstat", "r");
    if (f == NULL) {
        srs_warn("open vmstat failed, ignore");
        return false;
    }
    
    r.sample_time = srsu2ms(srs_update_system_time());
    
    static char buf[1024];
    while (fgets(buf, sizeof(buf), f)) {
        // @see: read_vmstat_paging() from https://github.com/sysstat/sysstat/blob/master/rd_stats.c#L495
        if (strncmp(buf, "pgpgin ", 7) == 0) {
            sscanf(buf + 7, "%lu\n", &r.pgpgin);
        } else if (strncmp(buf, "pgpgout ", 8) == 0) {
            sscanf(buf + 8, "%lu\n", &r.pgpgout);
        }
    }
    
    fclose(f);
#endif

    r.ok = true;
    
    return true;
}

bool srs_get_disk_diskstats_stat(SrsDiskStat& r)
{
    r.ok = true;
    r.sample_time = srsu2ms(srs_update_system_time());

#ifndef SRS_OSX
    // if disabled, ignore all devices.
    SrsConfDirective* conf = _srs_config->get_stats_disk_device();
    if (conf == NULL) {
        return true;
    }

    FILE* f = fopen("/proc/diskstats", "r");
    if (f == NULL) {
        srs_warn("open vmstat failed, ignore");
        return false;
    }
    
    static char buf[1024];
    while (fgets(buf, sizeof(buf), f)) {
        unsigned int major = 0;
        unsigned int minor = 0;
        static char name[32];
        unsigned int rd_ios = 0;
        unsigned int rd_merges = 0;
        unsigned long long rd_sectors = 0;
        unsigned int rd_ticks = 0;
        unsigned int wr_ios = 0;
        unsigned int wr_merges = 0;
        unsigned long long wr_sectors = 0;
        unsigned int wr_ticks = 0;
        unsigned int nb_current = 0;
        unsigned int ticks = 0;
        unsigned int aveq = 0;
        memset(name, 0, sizeof(name));
        
        sscanf(buf, "%4d %4d %31s %u %u %llu %u %u %u %llu %u %u %u %u",
               &major,
               &minor,
               name,
               &rd_ios,
               &rd_merges,
               &rd_sectors,
               &rd_ticks,
               &wr_ios,
               &wr_merges,
               &wr_sectors,
               &wr_ticks,
               &nb_current,
               &ticks,
               &aveq);
        
        for (int i = 0; i < (int)conf->args.size(); i++) {
            string name_ok = conf->args.at(i);
            
            if (strcmp(name_ok.c_str(), name) != 0) {
                continue;
            }
            
            r.rd_ios += rd_ios;
            r.rd_merges += rd_merges;
            r.rd_sectors += rd_sectors;
            r.rd_ticks += rd_ticks;
            r.wr_ios += wr_ios;
            r.wr_merges += wr_merges;
            r.wr_sectors += wr_sectors;
            r.wr_ticks += wr_ticks;
            r.nb_current += nb_current;
            r.ticks += ticks;
            r.aveq += aveq;
            
            break;
        }
    }
    
    fclose(f);
#endif

    r.ok = true;
    
    return true;
}

void srs_update_disk_stat()
{
    SrsDiskStat r;
    if (!srs_get_disk_vmstat_stat(r)) {
        return;
    }
    if (!srs_get_disk_diskstats_stat(r)) {
        return;
    }
    if (!get_proc_system_stat(r.cpu)) {
        return;
    }
    
    SrsDiskStat& o = _srs_disk_stat;
    if (!o.ok) {
        _srs_disk_stat = r;
        return;
    }
    
    // vmstat
    if (true) {
        int64_t duration_ms = r.sample_time - o.sample_time;
        
        if (o.pgpgin > 0 && r.pgpgin > o.pgpgin && duration_ms > 0) {
            // KBps = KB * 1000 / ms = KB/s
            r.in_KBps = (int)((r.pgpgin - o.pgpgin) * 1000 / duration_ms);
        }
        
        if (o.pgpgout > 0 && r.pgpgout > o.pgpgout && duration_ms > 0) {
            // KBps = KB * 1000 / ms = KB/s
            r.out_KBps = (int)((r.pgpgout - o.pgpgout) * 1000 / duration_ms);
        }
    }
    
    // diskstats
    if (r.cpu.ok && o.cpu.ok) {
        SrsCpuInfo* cpuinfo = srs_get_cpuinfo();
        r.cpu.total_delta = r.cpu.total() - o.cpu.total();
        
        if (r.cpu.ok && r.cpu.total_delta > 0
            && cpuinfo->ok && cpuinfo->nb_processors > 0
            && o.ticks < r.ticks
            ) {
            // @see: write_ext_stat() from https://github.com/sysstat/sysstat/blob/master/iostat.c#L979
            // TODO: FIXME: the USER_HZ assert to 100, so the total_delta ticks *10 is ms.
            double delta_ms = r.cpu.total_delta * 10 / cpuinfo->nb_processors;
            unsigned int ticks = r.ticks - o.ticks;
            
            // busy in [0, 1], where 0.1532 means 15.32%
            r.busy = (float)(ticks / delta_ms);
        }
    }
    
    _srs_disk_stat = r;
}

SrsMemInfo::SrsMemInfo()
{
    ok = false;
    sample_time = 0;
    
    percent_ram = 0;
    percent_swap = 0;
    
    MemActive = 0;
    RealInUse = 0;
    NotInUse = 0;
    MemTotal = 0;
    MemFree = 0;
    Buffers = 0;
    Cached = 0;
    SwapTotal = 0;
    SwapFree = 0;
}

static SrsMemInfo _srs_system_meminfo;

SrsMemInfo* srs_get_meminfo()
{
    return &_srs_system_meminfo;
}

void srs_update_meminfo()
{
    SrsMemInfo& r = _srs_system_meminfo;

#ifndef SRS_OSX
    FILE* f = fopen("/proc/meminfo", "r");
    if (f == NULL) {
        srs_warn("open meminfo failed, ignore");
        return;
    }
    
    static char buf[1024];
    while (fgets(buf, sizeof(buf), f)) {
        // @see: read_meminfo() from https://github.com/sysstat/sysstat/blob/master/rd_stats.c#L227
        if (strncmp(buf, "MemTotal:", 9) == 0) {
            sscanf(buf + 9, "%lu", &r.MemTotal);
        } else if (strncmp(buf, "MemFree:", 8) == 0) {
            sscanf(buf + 8, "%lu", &r.MemFree);
        } else if (strncmp(buf, "Buffers:", 8) == 0) {
            sscanf(buf + 8, "%lu", &r.Buffers);
        } else if (strncmp(buf, "Cached:", 7) == 0) {
            sscanf(buf + 7, "%lu", &r.Cached);
        } else if (strncmp(buf, "SwapTotal:", 10) == 0) {
            sscanf(buf + 10, "%lu", &r.SwapTotal);
        } else if (strncmp(buf, "SwapFree:", 9) == 0) {
            sscanf(buf + 9, "%lu", &r.SwapFree);
        }
    }
    
    fclose(f);
#endif

    r.sample_time = srsu2ms(srs_update_system_time());
    r.MemActive = r.MemTotal - r.MemFree;
    r.RealInUse = r.MemActive - r.Buffers - r.Cached;
    r.NotInUse = r.MemTotal - r.RealInUse;
    
    if (r.MemTotal > 0) {
        r.percent_ram = (float)(r.RealInUse / (double)r.MemTotal);
    }
    if (r.SwapTotal > 0) {
        r.percent_swap = (float)((r.SwapTotal - r.SwapFree) / (double)r.SwapTotal);
    }
    
    r.ok = true;
}

SrsCpuInfo::SrsCpuInfo()
{
    ok = false;
    
    nb_processors = 0;
    nb_processors_online = 0;
}

SrsCpuInfo* srs_get_cpuinfo()
{
    static SrsCpuInfo* cpu = NULL;
    if (cpu != NULL) {
        return cpu;
    }
    
    // initialize cpu info.
    cpu = new SrsCpuInfo();
    cpu->ok = true;
    cpu->nb_processors = (int)sysconf(_SC_NPROCESSORS_CONF);
    cpu->nb_processors_online = (int)sysconf(_SC_NPROCESSORS_ONLN);
    
    return cpu;
}

SrsPlatformInfo::SrsPlatformInfo()
{
    ok = false;
    
    srs_startup_time = 0;
    
    os_uptime = 0;
    os_ilde_time = 0;
    
    load_one_minutes = 0;
    load_five_minutes = 0;
    load_fifteen_minutes = 0;
}

static SrsPlatformInfo _srs_system_platform_info;

SrsPlatformInfo* srs_get_platform_info()
{
    return &_srs_system_platform_info;
}

void srs_update_platform_info()
{
    SrsPlatformInfo& r = _srs_system_platform_info;
    
    r.srs_startup_time = srsu2ms(srs_get_system_startup_time());

#ifndef SRS_OSX
    if (true) {
        FILE* f = fopen("/proc/uptime", "r");
        if (f == NULL) {
            srs_warn("open uptime failed, ignore");
            return;
        }
        
        fscanf(f, "%lf %lf\n", &r.os_uptime, &r.os_ilde_time);
        
        fclose(f);
    }
    
    if (true) {
        FILE* f = fopen("/proc/loadavg", "r");
        if (f == NULL) {
            srs_warn("open loadavg failed, ignore");
            return;
        }
        
        // @see: read_loadavg() from https://github.com/sysstat/sysstat/blob/master/rd_stats.c#L402
        // @remark, we use our algorithm, not sysstat.
        fscanf(f, "%lf %lf %lf\n",
               &r.load_one_minutes,
               &r.load_five_minutes,
               &r.load_fifteen_minutes);
        
        fclose(f);
    }
#else
    // man 3 sysctl
    if (true) {
        struct timeval tv;
        size_t len = sizeof(timeval);

        int mib[2];
        mib[0] = CTL_KERN;
        mib[1] = KERN_BOOTTIME;
        if (sysctl(mib, 2, &tv, &len, NULL, 0) < 0) {
            srs_warn("sysctl boottime failed, ignore");
            return;
        }

        time_t bsec = tv.tv_sec;
        time_t csec = ::time(NULL);
        r.os_uptime = difftime(csec, bsec);
    }

    // man 3 sysctl
    if (true) {
        struct loadavg la;
        size_t len = sizeof(loadavg);

        int mib[2];
        mib[0] = CTL_VM;
        mib[1] = VM_LOADAVG;
        if (sysctl(mib, 2, &la, &len, NULL, 0) < 0) {
            srs_warn("sysctl loadavg failed, ignore");
            return;
        }

        r.load_one_minutes = (double)la.ldavg[0] / la.fscale;
        r.load_five_minutes = (double)la.ldavg[1] / la.fscale;
        r.load_fifteen_minutes = (double)la.ldavg[2] / la.fscale;
    }
#endif

    r.ok = true;
}

SrsSnmpUdpStat::SrsSnmpUdpStat()
{
    ok = false;

    in_datagrams = 0;
    no_ports = 0;
    in_errors = 0;
    out_datagrams = 0;
    rcv_buf_errors = 0;
    snd_buf_errors = 0;
    in_csum_errors = 0;

    rcv_buf_errors_delta = 0;
    snd_buf_errors_delta = 0;
}

SrsSnmpUdpStat::~SrsSnmpUdpStat()
{
}

static SrsSnmpUdpStat _srs_snmp_udp_stat;

bool get_udp_snmp_statistic(SrsSnmpUdpStat& r)
{
#ifndef SRS_OSX
    if (true) {
        FILE* f = fopen("/proc/net/snmp", "r");
        if (f == NULL) {
            srs_warn("open proc network snmp failed, ignore");
            return false;
        }

        // ignore title.
        static char buf[1024];
        fgets(buf, sizeof(buf), f);

        while (fgets(buf, sizeof(buf), f)) {
            // udp stat title
            if (strncmp(buf, "Udp: ", 5) == 0) {
                // read tcp stat data
                if (!fgets(buf, sizeof(buf), f)) {
                    break;
                }
                // parse tcp stat data
                if (strncmp(buf, "Udp: ", 5) == 0) {
                    sscanf(buf + 5, "%llu %llu %llu %llu %llu %llu %llu\n",
                        &r.in_datagrams,
                        &r.no_ports,
                        &r.in_errors,
                        &r.out_datagrams,
                        &r.rcv_buf_errors,
                        &r.snd_buf_errors,
                        &r.in_csum_errors);
                }
            }
        }
        fclose(f);
    }
#endif
    r.ok = true;

    return true;
}

SrsSnmpUdpStat* srs_get_udp_snmp_stat()
{
    return &_srs_snmp_udp_stat;
}

void srs_update_udp_snmp_statistic()
{
    SrsSnmpUdpStat r;
    if (!get_udp_snmp_statistic(r)) {
        return;
    }

    SrsSnmpUdpStat& o = _srs_snmp_udp_stat;
    if (o.rcv_buf_errors > 0) {
        r.rcv_buf_errors_delta = int(r.rcv_buf_errors - o.rcv_buf_errors);
    }

    if (o.snd_buf_errors > 0) {
        r.snd_buf_errors_delta = int(r.snd_buf_errors - o.snd_buf_errors);
    }

    _srs_snmp_udp_stat = r;
}

SrsNetworkDevices::SrsNetworkDevices()
{
    ok = false;
    
    memset(name, 0, sizeof(name));
    sample_time = 0;
    
    rbytes = 0;
    rpackets = 0;
    rerrs = 0;
    rdrop = 0;
    rfifo = 0;
    rframe = 0;
    rcompressed = 0;
    rmulticast = 0;
    
    sbytes = 0;
    spackets = 0;
    serrs = 0;
    sdrop = 0;
    sfifo = 0;
    scolls = 0;
    scarrier = 0;
    scompressed = 0;
}

#define MAX_NETWORK_DEVICES_COUNT 16
static SrsNetworkDevices _srs_system_network_devices[MAX_NETWORK_DEVICES_COUNT];
static int _nb_srs_system_network_devices = -1;

SrsNetworkDevices* srs_get_network_devices()
{
    return _srs_system_network_devices;
}

int srs_get_network_devices_count()
{
    return _nb_srs_system_network_devices;
}

void srs_update_network_devices()
{
#ifndef SRS_OSX
    if (true) {
        FILE* f = fopen("/proc/net/dev", "r");
        if (f == NULL) {
            srs_warn("open proc network devices failed, ignore");
            return;
        }
        
        // ignore title.
        static char buf[1024];
        fgets(buf, sizeof(buf), f);
        fgets(buf, sizeof(buf), f);
        
        for (int i = 0; i < MAX_NETWORK_DEVICES_COUNT; i++) {
            if (!fgets(buf, sizeof(buf), f)) {
                break;
            }
            
            SrsNetworkDevices& r = _srs_system_network_devices[i];
            
            // @see: read_net_dev() from https://github.com/sysstat/sysstat/blob/master/rd_stats.c#L786
            // @remark, we use our algorithm, not sysstat.
            char fname[7];
            sscanf(buf, "%6[^:]:%llu %lu %lu %lu %lu %lu %lu %lu %llu %lu %lu %lu %lu %lu %lu %lu\n",
                   fname, &r.rbytes, &r.rpackets, &r.rerrs, &r.rdrop, &r.rfifo, &r.rframe, &r.rcompressed, &r.rmulticast,
                   &r.sbytes, &r.spackets, &r.serrs, &r.sdrop, &r.sfifo, &r.scolls, &r.scarrier, &r.scompressed);
            
            sscanf(fname, "%s", r.name);
            _nb_srs_system_network_devices = i + 1;
            srs_info("scan network device ifname=%s, total=%d", r.name, _nb_srs_system_network_devices);
            
            r.sample_time = srsu2ms(srs_update_system_time());
            r.ok = true;
        }
        
        fclose(f);
    }
#endif
}

SrsNetworkRtmpServer::SrsNetworkRtmpServer()
{
    ok = false;
    sample_time = rbytes = sbytes = 0;
    nb_conn_sys = nb_conn_srs = 0;
    nb_conn_sys_et = nb_conn_sys_tw = 0;
    nb_conn_sys_udp = 0;
    rkbps = skbps = 0;
    rkbps_30s = skbps_30s = 0;
    rkbps_5m = skbps_5m = 0;
}

static SrsNetworkRtmpServer _srs_network_rtmp_server;

SrsNetworkRtmpServer* srs_get_network_rtmp_server()
{
    return &_srs_network_rtmp_server;
}

// @see: http://stackoverflow.com/questions/5992211/list-of-possible-internal-socket-statuses-from-proc
enum {
    SYS_TCP_ESTABLISHED = 0x01,
    SYS_TCP_SYN_SENT,       // 0x02
    SYS_TCP_SYN_RECV,       // 0x03
    SYS_TCP_FIN_WAIT1,      // 0x04
    SYS_TCP_FIN_WAIT2,      // 0x05
    SYS_TCP_TIME_WAIT,      // 0x06
    SYS_TCP_CLOSE,          // 0x07
    SYS_TCP_CLOSE_WAIT,     // 0x08
    SYS_TCP_LAST_ACK,       // 0x09
    SYS_TCP_LISTEN,         // 0x0A
    SYS_TCP_CLOSING,        // 0x0B /* Now a valid state */
    
    SYS_TCP_MAX_STATES      // 0x0C /* Leave at the end! */
};

void srs_update_rtmp_server(int nb_conn, SrsKbps* kbps)
{
    SrsNetworkRtmpServer& r = _srs_network_rtmp_server;
    
    int nb_socks = 0;
    int nb_tcp4_hashed = 0;
    int nb_tcp_orphans = 0;
    int nb_tcp_tws = 0;
    int nb_tcp_total = 0;
    int nb_tcp_mem = 0;
    int nb_udp4 = 0;

#ifndef SRS_OSX
    if (true) {
        FILE* f = fopen("/proc/net/sockstat", "r");
        if (f == NULL) {
            srs_warn("open proc network sockstat failed, ignore");
            return;
        }
        
        // ignore title.
        static char buf[1024];
        fgets(buf, sizeof(buf), f);
        
        while (fgets(buf, sizeof(buf), f)) {
            // @see: et_sockstat_line() from https://github.com/shemminger/iproute2/blob/master/misc/ss.c
            if (strncmp(buf, "sockets: used ", 14) == 0) {
                sscanf(buf + 14, "%d\n", &nb_socks);
            } else if (strncmp(buf, "TCP: ", 5) == 0) {
                sscanf(buf + 5, "%*s %d %*s %d %*s %d %*s %d %*s %d\n",
                       &nb_tcp4_hashed,
                       &nb_tcp_orphans,
                       &nb_tcp_tws,
                       &nb_tcp_total,
                       &nb_tcp_mem);
            } else if (strncmp(buf, "UDP: ", 5) == 0) {
                sscanf(buf + 5, "%*s %d\n", &nb_udp4);
            }
        }
        
        fclose(f);
    }
#else
    // TODO: FIXME: impelments it.
    nb_socks = 0;
    nb_tcp4_hashed = 0;
    nb_tcp_orphans = 0;
    nb_tcp_tws = 0;
    nb_tcp_total = 0;
    nb_tcp_mem = 0;
    nb_udp4 = 0;
#endif

    int nb_tcp_estab = 0;

#ifndef SRS_OSX
    if (true) {
        FILE* f = fopen("/proc/net/snmp", "r");
        if (f == NULL) {
            srs_warn("open proc network snmp failed, ignore");
            return;
        }
        
        // ignore title.
        static char buf[1024];
        fgets(buf, sizeof(buf), f);
        
        // @see: https://github.com/shemminger/iproute2/blob/master/misc/ss.c
        while (fgets(buf, sizeof(buf), f)) {
            // @see: get_snmp_int("Tcp:", "CurrEstab", &sn.tcp_estab)
            // tcp stat title
            if (strncmp(buf, "Tcp: ", 5) == 0) {
                // read tcp stat data
                if (!fgets(buf, sizeof(buf), f)) {
                    break;
                }
                // parse tcp stat data
                if (strncmp(buf, "Tcp: ", 5) == 0) {
                    sscanf(buf + 5, "%*d %*d %*d %*d %*d %*d %*d %*d %d\n", &nb_tcp_estab);
                }
            }
        }
        
        fclose(f);
    }
#endif

    // @see: https://github.com/shemminger/iproute2/blob/master/misc/ss.c
    // TODO: FIXME: ignore the slabstat, @see: get_slabstat()
    if (true) {
        // @see: print_summary()
        r.nb_conn_sys = nb_tcp_total + nb_tcp_tws;
        r.nb_conn_sys_et = nb_tcp_estab;
        r.nb_conn_sys_tw = nb_tcp_tws;
        r.nb_conn_sys_udp = nb_udp4;
    }
    
    if (true) {
        r.ok = true;
        
        r.nb_conn_srs = nb_conn;
        r.sample_time = srsu2ms(srs_update_system_time());
        
        r.rbytes = kbps->get_recv_bytes();
        r.rkbps = kbps->get_recv_kbps();
        r.rkbps_30s = kbps->get_recv_kbps_30s();
        r.rkbps_5m = kbps->get_recv_kbps_5m();
        
        r.sbytes = kbps->get_send_bytes();
        r.skbps = kbps->get_send_kbps();
        r.skbps_30s = kbps->get_send_kbps_30s();
        r.skbps_5m = kbps->get_send_kbps_5m();
    }
}

string srs_get_local_ip(int fd)
{
    // discovery client information
    sockaddr_storage addr;
    socklen_t addrlen = sizeof(addr);
    if (getsockname(fd, (sockaddr*)&addr, &addrlen) == -1) {
        return "";
    }

    char saddr[64];
    char* h = (char*)saddr;
    socklen_t nbh = (socklen_t)sizeof(saddr);
    const int r0 = getnameinfo((const sockaddr*)&addr, addrlen, h, nbh,NULL, 0, NI_NUMERICHOST);
    if(r0) {
        return "";
    }

    return std::string(saddr);
}

int srs_get_local_port(int fd)
{
    // discovery client information
    sockaddr_storage addr;
    socklen_t addrlen = sizeof(addr);
    if (getsockname(fd, (sockaddr*)&addr, &addrlen) == -1) {
        return 0;
    }

    int port = 0;
    switch(addr.ss_family) {
        case AF_INET:
            port = ntohs(((sockaddr_in*)&addr)->sin_port);
         break;
        case AF_INET6:
            port = ntohs(((sockaddr_in6*)&addr)->sin6_port);
         break;
    }

    return port;
}

string srs_get_peer_ip(int fd)
{
    // discovery client information
    sockaddr_storage addr;
    socklen_t addrlen = sizeof(addr);
    if (getpeername(fd, (sockaddr*)&addr, &addrlen) == -1) {
        return "";
    }

    char saddr[64];
    char* h = (char*)saddr;
    socklen_t nbh = (socklen_t)sizeof(saddr);
    const int r0 = getnameinfo((const sockaddr*)&addr, addrlen, h, nbh, NULL, 0, NI_NUMERICHOST);
    if(r0) {
        return "";
    }

    return std::string(saddr);
}

int srs_get_peer_port(int fd)
{
    // discovery client information
    sockaddr_storage addr;
    socklen_t addrlen = sizeof(addr);
    if (getpeername(fd, (sockaddr*)&addr, &addrlen) == -1) {
        return 0;
    }

    int port = 0;
    switch(addr.ss_family) {
        case AF_INET:
            port = ntohs(((sockaddr_in*)&addr)->sin_port);
         break;
        case AF_INET6:
            port = ntohs(((sockaddr_in6*)&addr)->sin6_port);
         break;
    }

    return port;
}

bool srs_is_boolean(string str)
{
    return str == "true" || str == "false";
}

void srs_api_dump_summaries(SrsJsonObject* obj)
{
    SrsRusage* r = srs_get_system_rusage();
    SrsProcSelfStat* u = srs_get_self_proc_stat();
    SrsProcSystemStat* s = srs_get_system_proc_stat();
    SrsCpuInfo* c = srs_get_cpuinfo();
    SrsMemInfo* m = srs_get_meminfo();
    SrsPlatformInfo* p = srs_get_platform_info();
    SrsNetworkDevices* n = srs_get_network_devices();
    SrsNetworkRtmpServer* nrs = srs_get_network_rtmp_server();
    SrsDiskStat* d = srs_get_disk_stat();
    
    float self_mem_percent = 0;
    if (m->MemTotal > 0) {
        self_mem_percent = (float)(r->r.ru_maxrss / (double)m->MemTotal);
    }
    
    int64_t now = srsu2ms(srs_update_system_time());
    double srs_uptime = (now - p->srs_startup_time) / 100 / 10.0;
    
    int64_t n_sample_time = 0;
    int64_t nr_bytes = 0;
    int64_t ns_bytes = 0;
    int64_t nri_bytes = 0;
    int64_t nsi_bytes = 0;
    int nb_n = srs_get_network_devices_count();
    for (int i = 0; i < nb_n; i++) {
        SrsNetworkDevices& o = n[i];
        
        // ignore the lo interface.
        std::string inter = o.name;
        if (!o.ok) {
            continue;
        }
        
        // update the sample time.
        n_sample_time = o.sample_time;
        
        // stat the intranet bytes.
        if (inter == "lo" || !srs_net_device_is_internet(inter)) {
            nri_bytes += o.rbytes;
            nsi_bytes += o.sbytes;
            continue;
        }
        
        nr_bytes += o.rbytes;
        ns_bytes += o.sbytes;
    }
    
    // all data is ok?
    bool ok = (r->ok && u->ok && s->ok && c->ok
               && d->ok && m->ok && p->ok && nrs->ok);
    
    SrsJsonObject* data = SrsJsonAny::object();
    obj->set("data", data);
    
    data->set("ok", SrsJsonAny::boolean(ok));
    data->set("now_ms", SrsJsonAny::integer(now));
    
    // self
    SrsJsonObject* self = SrsJsonAny::object();
    data->set("self", self);
    
    self->set("version", SrsJsonAny::str(RTMP_SIG_SRS_VERSION));
    self->set("pid", SrsJsonAny::integer(getpid()));
    self->set("ppid", SrsJsonAny::integer(u->ppid));
    self->set("argv", SrsJsonAny::str(_srs_config->argv().c_str()));
    self->set("cwd", SrsJsonAny::str(_srs_config->cwd().c_str()));
    self->set("mem_kbyte", SrsJsonAny::integer(r->r.ru_maxrss));
    self->set("mem_percent", SrsJsonAny::number(self_mem_percent));
    self->set("cpu_percent", SrsJsonAny::number(u->percent));
    self->set("srs_uptime", SrsJsonAny::integer(srs_uptime));
    
    // system
    SrsJsonObject* sys = SrsJsonAny::object();
    data->set("system", sys);
    
    sys->set("cpu_percent", SrsJsonAny::number(s->percent));
    sys->set("disk_read_KBps", SrsJsonAny::integer(d->in_KBps));
    sys->set("disk_write_KBps", SrsJsonAny::integer(d->out_KBps));
    sys->set("disk_busy_percent", SrsJsonAny::number(d->busy));
    sys->set("mem_ram_kbyte", SrsJsonAny::integer(m->MemTotal));
    sys->set("mem_ram_percent", SrsJsonAny::number(m->percent_ram));
    sys->set("mem_swap_kbyte", SrsJsonAny::integer(m->SwapTotal));
    sys->set("mem_swap_percent", SrsJsonAny::number(m->percent_swap));
    sys->set("cpus", SrsJsonAny::integer(c->nb_processors));
    sys->set("cpus_online", SrsJsonAny::integer(c->nb_processors_online));
    sys->set("uptime", SrsJsonAny::number(p->os_uptime));
    sys->set("ilde_time", SrsJsonAny::number(p->os_ilde_time));
    sys->set("load_1m", SrsJsonAny::number(p->load_one_minutes));
    sys->set("load_5m", SrsJsonAny::number(p->load_five_minutes));
    sys->set("load_15m", SrsJsonAny::number(p->load_fifteen_minutes));
    // system network bytes stat.
    sys->set("net_sample_time", SrsJsonAny::integer(n_sample_time));
    // internet public address network device bytes.
    sys->set("net_recv_bytes", SrsJsonAny::integer(nr_bytes));
    sys->set("net_send_bytes", SrsJsonAny::integer(ns_bytes));
    // intranet private address network device bytes.
    sys->set("net_recvi_bytes", SrsJsonAny::integer(nri_bytes));
    sys->set("net_sendi_bytes", SrsJsonAny::integer(nsi_bytes));
    // srs network bytes stat.
    sys->set("srs_sample_time", SrsJsonAny::integer(nrs->sample_time));
    sys->set("srs_recv_bytes", SrsJsonAny::integer(nrs->rbytes));
    sys->set("srs_send_bytes", SrsJsonAny::integer(nrs->sbytes));
    sys->set("conn_sys", SrsJsonAny::integer(nrs->nb_conn_sys));
    sys->set("conn_sys_et", SrsJsonAny::integer(nrs->nb_conn_sys_et));
    sys->set("conn_sys_tw", SrsJsonAny::integer(nrs->nb_conn_sys_tw));
    sys->set("conn_sys_udp", SrsJsonAny::integer(nrs->nb_conn_sys_udp));
    sys->set("conn_srs", SrsJsonAny::integer(nrs->nb_conn_srs));
}

string srs_string_dumps_hex(const std::string& str)
{
    return srs_string_dumps_hex(str.c_str(), str.size());
}

string srs_string_dumps_hex(const char* str, int length)
{
    return srs_string_dumps_hex(str, length, INT_MAX);
}

string srs_string_dumps_hex(const char* str, int length, int limit)
{
    return srs_string_dumps_hex(str, length, limit, ' ', 128, '\n');
}

string srs_string_dumps_hex(const char* str, int length, int limit, char seperator, int line_limit, char newline)
{
    // 1 byte trailing '\0'.
    const int LIMIT = 1024*16 + 1;
    static char buf[LIMIT];

    int len = 0;
    for (int i = 0; i < length && i < limit && len < LIMIT; ++i) {
        int nb = snprintf(buf + len, LIMIT - len, "%02x", (uint8_t)str[i]);
        if (nb < 0 || nb >= LIMIT - len) {
            break;
        }
        len += nb;

        // Only append seperator and newline when not last byte.
        if (i < length - 1 && i < limit - 1 && len < LIMIT) {
            if (seperator) {
                buf[len++] = seperator;
            }

            if (newline && line_limit && i > 0 && ((i + 1) % line_limit) == 0) {
                buf[len++] = newline;
            }
        }
    }

    // Empty string.
    if (len <= 0) {
        return "";
    }

    // If overflow, cut the trailing newline.
    if (newline && len >= LIMIT - 2 && buf[len - 1] == newline) {
        len--;
    }

    // If overflow, cut the trailing seperator.
    if (seperator && len >= LIMIT - 3 && buf[len - 1] == seperator) {
        len--;
    }

    return string(buf, len);
}

string srs_getenv(string key)
{
    string ekey = key;
    if (srs_string_starts_with(key, "$")) {
        ekey = key.substr(1);
    }

    if (ekey.empty()) {
        return "";
    }

    char* value = ::getenv(ekey.c_str());
    if (value) {
        return value;
    }

    return "";
}