#include "signals.h"
#include "utils.h"

#include <yql/essentials/utils/backtrace/backtrace.h>

#include <util/stream/output.h>
#include <util/generic/yexception.h>
#include <util/datetime/base.h>
#include <util/network/socket.h>
#include <util/system/getpid.h>

#ifdef _linux_
#   include <sys/prctl.h>
#endif

#include <string.h>
#include <signal.h>
#include <errno.h>
#include <stdlib.h>


namespace NYql {

volatile sig_atomic_t NeedTerminate = 0;
volatile sig_atomic_t NeedQuit = 0;
volatile sig_atomic_t NeedReconfigure = 0;
volatile sig_atomic_t NeedReopenLog = 0;
volatile sig_atomic_t NeedReapZombies = 0;
volatile sig_atomic_t NeedInterrupt = 0;

volatile sig_atomic_t CatchInterrupt = 0;

TPipe SignalPipeW;
TPipe SignalPipeR;

namespace {

void SignalHandler(int signo)
{
    switch (signo) {
    case SIGTERM:
        NeedTerminate = 1;
        break;

    case SIGQUIT:
        NeedQuit = 1;
        break;

#ifdef _unix_
    case SIGHUP:
        NeedReconfigure = 1;
        break;

    case SIGUSR1:
        NeedReopenLog = 1;
        break;

    case SIGCHLD:
        NeedReapZombies = 1;
        break;
#endif

    case SIGINT:
        if (CatchInterrupt) {
            NeedInterrupt = 1;
        } else {
            fprintf(stderr, "%s (pid=%d) captured SIGINT\n",
                    GetProcTitle(), getpid());
            signal(signo, SIG_DFL);
            raise(signo);
        }
        break;

    default:
        break;
    }
}

void SignalHandlerWithSelfPipe(int signo)
{
    SignalHandler(signo);

    int savedErrno = errno;
    if (write(SignalPipeW.GetHandle(), "x", 1) == -1 && errno != EAGAIN) {
        static TStringBuf msg("cannot write to signal pipe");
#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif
        write(STDERR_FILENO, msg.data(), msg.size());
        abort();
    }
    errno = savedErrno;
}


#ifndef _unix_
const char* strsignal(int signo)
{
    switch (signo) {
    case SIGTERM: return "SIGTERM";
    case SIGINT: return "SIGINT";
    case SIGQUIT: return "SIGQUIT";
    default:
        return "UNKNOWN";
    }
}
#endif


#ifdef _unix_
int SetSignalHandler(int signo, void (*handler)(int))
{
    struct sigaction sa;
    sa.sa_flags = SA_RESTART;
    sa.sa_handler = handler;
    sigemptyset(&sa.sa_mask);

    return sigaction(signo, &sa, nullptr);
}

#else
int SetSignalHandler(int signo, void (*handler)(int))
{
    return (signal(signo, handler) == SIG_ERR) ? -1 : 0;
}

#endif

struct TSignalHandlerDesc
{
    int signo;
    void (*handler)(int);
};

void SetSignalHandlers(const TSignalHandlerDesc* handlerDescs)
{
    sigset_t interestedSignals;
    SigEmptySet(&interestedSignals);

    for (int i = 0; handlerDescs[i].signo != -1; i++) {
        int signo = handlerDescs[i].signo;
        SigAddSet(&interestedSignals, signo);

        if (SetSignalHandler(signo, handlerDescs[i].handler) == -1) {
            ythrow TSystemError() << "Cannot set handler for signal "
                                  << strsignal(signo);
        }
    }

    if (SigProcMask(SIG_BLOCK, &interestedSignals, NULL) == -1) {
        ythrow TSystemError() << "Cannot set sigprocmask";
    }

    NYql::NBacktrace::RegisterKikimrFatalActions();
}

} // namespace


void InitSignals()
{
    TSignalHandlerDesc handlerDescs[] = {
        { SIGTERM, SignalHandler },
        { SIGINT, SignalHandler },
        { SIGQUIT, SignalHandler },
#ifdef _unix_
        { SIGPIPE, SIG_IGN },
        { SIGHUP, SignalHandler },
        { SIGUSR1, SignalHandler },
        { SIGCHLD, SignalHandler },
#endif
        { -1, nullptr }
    };

    SetSignalHandlers(handlerDescs);
}

void InitSignalsWithSelfPipe()
{
    TSignalHandlerDesc handlerDescs[] = {
        { SIGTERM, SignalHandlerWithSelfPipe },
        { SIGINT, SignalHandlerWithSelfPipe },
        { SIGQUIT, SignalHandlerWithSelfPipe },
#ifdef _unix_
        { SIGPIPE, SIG_IGN },
        { SIGHUP, SignalHandlerWithSelfPipe },
        { SIGUSR1, SignalHandlerWithSelfPipe },
        { SIGCHLD, SignalHandlerWithSelfPipe },
#endif
        { -1, nullptr }
    };

    TPipe::Pipe(SignalPipeR, SignalPipeW);
    SetNonBlock(SignalPipeR.GetHandle());
    SetNonBlock(SignalPipeW.GetHandle());

    SetSignalHandlers(handlerDescs);
}

void CatchInterruptSignal(bool doCatch) {
    CatchInterrupt = doCatch;
}

void SigSuspend(const sigset_t* mask)
{
#ifdef _unix_
    sigsuspend(mask);
#else
    Y_UNUSED(mask);
    Sleep(TDuration::Seconds(1));
#endif
}

void AllowAnySignals()
{
    sigset_t blockMask;
    SigEmptySet(&blockMask);

    if (SigProcMask(SIG_SETMASK, &blockMask, NULL) == -1) {
        ythrow TSystemError() << "Cannot set sigprocmask";
    }
}

bool HasPendingQuitOrTerm() {
#ifdef _unix_
    sigset_t signals;
    SigEmptySet(&signals);
    if (sigpending(&signals)) {
        ythrow TSystemError() << "Error in sigpending";
    }

    return (SigIsMember(&signals, SIGQUIT) == 1) || (SigIsMember(&signals, SIGTERM) == 1);
#else
    return false;
#endif
}
} // namespace NYql