/***
    Copyright (C) 2021-2024 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: ExceptionWatcher.Linux.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "ExceptionWatcher.Unix.hpp"

#include "Debug.hpp"
#include <Source/Telemetry/Telemetry.hpp>
#include <Source/Grug/AuGrug.hpp>
#include <Source/Console/Console.hpp>
#include <Source/Exit/AuExit.hpp>
#include "ErrorStack.hpp"

#if defined(AURORA_PLATFORM_LINUX)
    #include "unwind.h"
#endif

#include "Stack.Unix.hpp"

#include <cxxabi.h>

#if defined(AURORA_PLATFORM_LINUX) && defined(AURORA_ARCH_X64)
    #define DEBUG_ABI_ALPHA
#endif

#if defined(AURORA_PLATFORM_LINUX) && (defined(AURORA_ARCH_X64) || defined(AURORA_ARCH_X86))
    #define DEBUG_ABI_IS_IT_AND_SYSV_LIKE
#endif

#if defined(AURORA_PLATFORM_LINUX)
    #include <libunwind.h>
#endif

namespace Aurora::Debug
{
    static const AuUInt8 kCriticalAlwaysCoreDumpSignals[] {
        SIGABRT,
        SIGBUS,
        SIGILL,
        SIGIOT,
        SIGQUIT,
        SIGSEGV,
        SIGSYS,
        SIGTRAP,
        //SIGUNUSED,
        SIGFPE,
        SIGXFSZ
    };

    static const AuUInt8 kTypeIgnoreNOP    = 0;
    static const AuUInt8 kTypeIgnoreAndLog = 1;
    static const AuUInt8 kTypeCoreDump     = 2;

    static AuUInt8       gSignalHandlerMap[64] {};

    static void SaveMinidump(void *optContext,
                             void *pException,
                             int iSignal,
                             AuUInt32 uThread,
                             AuString &pathOut)
    {

    }

    static void PlatformHandleFatalEx(bool fatal, bool bNoExit, void *context, AuUInt32 uThreadID)
    {
        AuString path;

        SaveMinidump(context, nullptr, 0, uThreadID, path);

        if (fatal)
        {
            if (path.size())
            {
                Telemetry::NewBlackBoxEntryMinidump report {};
                report.includesRx = false;
                report.resource.path = path;
                report.resource.type = Telemetry::ENewBlackBoxResourceType::eLocal;
                Telemetry::ReportDyingBreath(report);
            }

            PosixTerminate();
        }
    }

    struct SigArrow : Grug::Arrow
    {
        int signal {};
        void *context {};
        AuUInt32 uPosixThread {};
        AuUInt thread;
        AuString signalStr;
    };

    static void SendLogMessage(Grug::Arrow *pArrow)
    {
        auto pArrowEx = AuStaticCast<SigArrow>(pArrow);
        AuLogDbg("Caught signal {} ({}) on {}/{}", strsignal(pArrowEx->signal), pArrowEx->signal, pArrowEx->thread, pArrowEx->uPosixThread);

        Exit::PostLevel((AuThreads::IAuroraThread *)pArrowEx->thread, Exit::ETriggerLevel::eProblematicEvent);
    }

    static void SendCoreDump(Grug::Arrow *pArrow)
    {
        auto pArrowEx = AuStaticCast<SigArrow>(pArrow);

        {
            StackTrace trace;

            if (pArrowEx->context)
            {
                trace = DumpContext(pArrowEx->context);
            }

            if (gRuntimeConfig.debug.bPrintExceptionStackTracesOut)
            {
                AuLogWarn("Fatal Signal: 0x{:x}, {} ({})", pArrowEx->thread, strsignal(pArrowEx->signal), pArrowEx->signal);
                AuLogWarn("{}", StringifyStackTrace(trace));
            }

            {
                Telemetry::NewBlockboxEntry entry;
                entry.type = Telemetry::ENewBlackBoxEntry::eStackWarning;
                entry.stack.fenceId = ReportStackTrace(trace, AuToString(pArrowEx->signal));
                entry.stack.backtrace = trace;
                Telemetry::Report(entry);
            }
        }

        {
            Exit::PostLevel((AuThreads::IAuroraThread *)pArrowEx->thread, Exit::ETriggerLevel::eFatalException);
        }

        {
            AuString path;
            SaveMinidump(pArrowEx->context, nullptr, pArrowEx->signal, pArrowEx->uPosixThread, path);
            
            if (path.size())
            {
                Telemetry::NewBlackBoxEntryMinidump report {};
                report.includesRx = false;
                report.resource.path = path;
                report.resource.type = Telemetry::ENewBlackBoxResourceType::eLocal;
                Telemetry::ReportDyingBreath(report);
            }

        }
        {
            Grug::GrugFlushWrites();
            Grug::GrugFlushFlushs();
            Console::Pump();
        }

        PosixTerminate();
    }


    static void SendCoreDumpOfException(Grug::Arrow *pArrow)
    {
        auto pArrowEx = AuStaticCast<SigArrow>(pArrow);

        {
            StackTrace trace;

            if (pArrowEx->context)
            {
                trace = DumpContext(pArrowEx->context);
            }

            if (gRuntimeConfig.debug.bPrintExceptionStackTracesOut)
            {
                AuLogWarn("Fatal Exception: 0x{:x}, {}", pArrowEx->thread, pArrowEx->signalStr);
                AuLogWarn("{}", StringifyStackTrace(trace));
            }

            {
                Telemetry::NewBlockboxEntry entry;
                entry.type = Telemetry::ENewBlackBoxEntry::eStackWarning;
                entry.stack.fenceId = ReportStackTrace(trace, AuToString(pArrowEx->signal));
                entry.stack.backtrace = trace;
                Telemetry::Report(entry);
            }
        }

        {
            Exit::PostLevel((AuThreads::IAuroraThread *)pArrowEx->thread, Exit::ETriggerLevel::eFatalException);
        }

        {
            AuString path;
            SaveMinidump(pArrowEx->context, nullptr, pArrowEx->signal, pArrowEx->uPosixThread, path);
            
            if (path.size())
            {
                Telemetry::NewBlackBoxEntryMinidump report {};
                report.includesRx = false;
                report.resource.path = path;
                report.resource.type = Telemetry::ENewBlackBoxResourceType::eLocal;
                Telemetry::ReportDyingBreath(report);
            }

        }
        {
            Grug::GrugFlushWrites();
            Grug::GrugFlushFlushs();
            Console::Pump();
        }

        PosixTerminate();
    }

    static void PosixCrashTrap(int signal, siginfo_t *si, void *context)
    {
        void (*pSendExitSignal_f)(Grug::Arrow *);
        SigArrow arrow;

        arrow.signal = signal;
        arrow.thread = AuThreads::GetThreadId();
        arrow.context = context;
        arrow.uPosixThread = getpid();

        switch (gSignalHandlerMap[signal])
        {
        case kTypeIgnoreNOP:
            return;

        case kTypeIgnoreAndLog:
            pSendExitSignal_f = SendLogMessage;
            break;

        case kTypeCoreDump:
            pSendExitSignal_f = SendCoreDump;
            break;
        }

        Grug::HurlArrow(&arrow, pSendExitSignal_f, {});
        Grug::ArrowWait(&arrow);

        if (pSendExitSignal_f == SendCoreDump)
        {
            PosixTerminate();
        }
    }

    static void PosixSendExceptionCrash(const AuString &str, void *context)
    {
        SigArrow arrow;

        arrow.signalStr = str;
        arrow.thread = AuThreads::GetThreadId();
        arrow.context = context;
        arrow.uPosixThread = getpid();

        Grug::HurlArrow(&arrow, SendCoreDumpOfException, {});
        Grug::ArrowWait(&arrow);

        PosixTerminate();
    }

    void PlatformHandleFatal(bool bFatal, bool bNoExit)
    {
        PlatformHandleFatalEx(bFatal, bNoExit, nullptr, getpid());
    }

    static void InstallSignalHandlerOnSignal(AuUInt8 uSignal)
    {
        struct sigaction action =
        {
            .sa_handler = (void (*)(int))PosixCrashTrap,
            .sa_flags = SA_ONSTACK
        };
        sigemptyset(&action.sa_mask);
        sigaction(uSignal, &action, nullptr);
    }

    static void RemoveSignalHandlerOnSignal(AuUInt8 uSignal)
    {
        struct sigaction action =
        {
            .sa_handler = SIG_DFL,
            .sa_flags = SA_ONSTACK
        };
        sigemptyset(&action.sa_mask);
        sigaction(uSignal, &action, nullptr);
    }

    static void OverrideCriticalSignals()
    {
        for (AU_ITERATE_N(i, AuArraySize(kCriticalAlwaysCoreDumpSignals)))
        {
            auto uSignal = kCriticalAlwaysCoreDumpSignals[i];
            gSignalHandlerMap[uSignal] = kTypeCoreDump;
            InstallSignalHandlerOnSignal(uSignal);
        }
    }

    void InitUNIX()
    {
        OverrideCriticalSignals();
    }

    void DeinitSignalHandlers()
    {
        for (AU_ITERATE_N(uSignal, AuArraySize(gSignalHandlerMap)))
        {
            if (gSignalHandlerMap[uSignal] == kTypeIgnoreNOP)
            {
                continue;
            }

            RemoveSignalHandlerOnSignal(uSignal);
        }
    }

    static void ReportException(void *pException,
                                std::type_info *pInfo,
                                const StackTrace &trace,
                                AuConsumer<const AuString &> func = {})
    {
        AuString message { "EMPTY" };

        if (pInfo)
        {
            //AuLogDbg("Base RTTI of the type info: {}", ((char ****)pInfo)[0][-1][1]); 
            bool bIsStdExceptionDerived {};

        #if defined(DEBUG_ABI_IS_IT_AND_SYSV_LIKE)
            if (strcmp(((char ****)pInfo)[0][-1][1], "N10__cxxabiv120__si_class_type_infoE") == 0)
            {
                char **pInfoCur = ((char ****)pException)[0][-1];
                while (pInfoCur)
                {
                    if (strcmp(pInfoCur[1], "St9exception") == 0)
                    {
                        bIsStdExceptionDerived = true;
                        break;
                    }
                    auto pOld = pInfoCur;
                    pInfoCur = (char **)pInfoCur[2];
                    if (pOld == pInfoCur)
                    {
                        break;
                    }
                }
            }
        #endif

            if (*pInfo == typeid(const char*))
            {
                message = fmt::format("Exception Type: {}, Message: {}", pInfo->name(), pException ? *(const char**)pException : "<NULL>");
            }
            else if (*pInfo == typeid(char* const))
            {
                message = fmt::format("Exception Type: {}, Message: {}", pInfo->name(), pException ? *(const char**)pException : "<NULL>");
            }
        #define ADD_FMT_PRIM(type) \
            else if (*pInfo == typeid(type)) \
            { \
                message = fmt::format("Exception Type: {}, Data: {}", pInfo->name(), pException ? *(type*)pException : type {}); \
            }

        ADD_FMT_PRIM(std::string)
        ADD_FMT_PRIM(double)
        ADD_FMT_PRIM(float)
        ADD_FMT_PRIM(AuUInt8)
        ADD_FMT_PRIM(AuUInt16)
        ADD_FMT_PRIM(AuUInt32)
        ADD_FMT_PRIM(AuUInt64)
        ADD_FMT_PRIM(AuInt8)
        ADD_FMT_PRIM(AuInt16)
        ADD_FMT_PRIM(AuInt32)
        ADD_FMT_PRIM(AuInt64)

            else if (bIsStdExceptionDerived)
            {
                message = fmt::format("Exception Type: {}, Message: {}", pInfo->name(), ((std::exception *)pException)->what());
            }
            else
            {
                message = fmt::format("Exception Type: {}", pInfo->name());
            }
        }
   
        if (func)
        {
            func(message);
        }

        {
            Telemetry::NewBlockboxEntry entry;
            entry.type = Telemetry::ENewBlackBoxEntry::eStackWarning;
            entry.stack.fenceId = ReportStackTrace(trace, message);
            entry.stack.backtrace = trace;
            Telemetry::Report(entry);
       
            auto pStr = AuMakeSharedPanic<AuString>(message);
           // auto pTrace = AuMakeSharedThrow<StackTrace>(trace);

            if (ShouldPushErrorStackInternal())
            {
                auto pMessage = AuMakeSharedThrow<ThreadMessage>();
                pMessage->optStackTrace = trace;
                pMessage->pStringMessage = pStr;
                PushErrorStackInternal(pMessage);
            }
        }
    }

    static void PosixHandleExceptionThrow(void *pException, std::type_info *pInfo, bool bLinuxException)
    {
        AU_DEBUG_MEMCRUNCH;

    #if defined(AURORA_PLATFORM_LINUX)
        ::unw_context_t uc;
        ::unw_getcontext(&uc);
        void *pContext = &uc;
        auto trace = DumpContext(uc);
    #else
        auto trace = GetStackTrace();
        void *pContext = nullptr;
    #endif

        AuString reportFatal;

        if (gRuntimeConfig.debug.bPrintExceptionStackTracesOut)
        {
            ReportException(pException, pInfo, trace, [&](const AuString &str)
            {
                if (bLinuxException)
                {
                    AuLogWarn("Local Linux Exception: 0x{:x}, {}", AuUInt(pException), str.c_str());
                }
                else
                {
                    AuLogWarn("Local Clang Exception: 0x{:x}, {}", AuUInt(pException), str.c_str());
                }
                AuLogWarn("{}", StringifyStackTrace(trace));

                if (gRuntimeConfig.debug.bIsExceptionThrowFatal)
                {
                    reportFatal = str;
                }
            });
        }
        else
        {
            if (gRuntimeConfig.debug.bIsExceptionThrowFatal)
            {
                ReportException(pException, pInfo, trace, [&](const AuString &str)
                {
                    reportFatal = str;
                });
            }
            else
            {
                ReportException(pException, pInfo, trace);
            }
        }

        if (gRuntimeConfig.debug.bIsExceptionThrowFatal)
        {
            PosixSendExceptionCrash(reportFatal, pContext);
        }
        else
        {
            AuExit::PostLevel(AuThreads::GetThread(), AuExit::ETriggerLevel::eProblematicEvent);
        }
    }

    static AU_NORETURN void __au_cxa_throw(void *pException, std::type_info *pInfo, void (*fDtor)(void *pThis))
    {
        if (Grug::IsGrug())
        {
            SysAssert(p__cxa_throw, "NST");
            p__cxa_throw(pException, pInfo, fDtor);
        }

        {
            PosixHandleExceptionThrow(pException, pInfo, false);
        }

        {
            SysAssert(p__cxa_throw, "NST");
            p__cxa_throw(pException, pInfo, fDtor);
        }
    }

#if defined(AURORA_PLATFORM_LINUX)
    static _Unwind_Reason_Code __au_Unwind_RaiseException(void *pException, std::type_info *pInfo, struct _Unwind_Exception *pUnwind)
    {
        if (Grug::IsGrug())
        {
            SysAssert(p_Unwind_RaiseException, "URE");
            return (_Unwind_Reason_Code)p_Unwind_RaiseException(pUnwind);
        }

        {
            PosixHandleExceptionThrow(pException, pInfo, true);
        }

        {
            SysAssert(p_Unwind_RaiseException, "URE");
            return (_Unwind_Reason_Code)p_Unwind_RaiseException(pUnwind);
        }
    }
#endif
}

AUKN_SYM void AU_NORETURN __au_cxa_throw(void *pException, std::type_info *pInfo, void (*fDtor)(void *pThis))
{
    Aurora::Debug::__au_cxa_throw(pException, pInfo, fDtor);
}

#if defined(AURORA_PLATFORM_LINUX)

AUKN_SYM extern "C" _Unwind_Reason_Code _au_Unwind_RaiseException(struct _Unwind_Exception *pUnwind)
{
    _Unwind_Exception *exception_header = pUnwind;
    
    auto pException = (void **)(&pUnwind[1]);

#if defined(DEBUG_ABI_ALPHA)
    auto pInfo = *(std::type_info **)((char *)pUnwind - 80);
    // TODO: Test for clangs termination handler to somewhat verify that we are parsing a known structure layout
#else
    std::type_info *pInfo { nullptr };
#endif

    return Aurora::Debug::__au_Unwind_RaiseException(pException, pInfo, pUnwind);
}

#endif