/* Copyright (C) 2015
 * swift Project Community / Contributors
 *
 * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
 * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
 * or distributed except according to the terms contained in the LICENSE file.
 */

#include "blackmisc/stacktrace.h"

#include <stdlib.h>
#include <QByteArray>
#include <QLatin1String>
#include <QStringBuilder>
#include <QMutexLocker>
#include <array>
#include <cstdlib>
#include <mutex>

#if defined(Q_CC_MSVC)
#   include <windows.h>

#   pragma warning(push)
#   pragma warning(disable:4091)
#   include <dbghelp.h>

#   pragma warning(pop)
#elif defined(Q_OS_WIN) && defined (Q_CC_GNU)
#   include <windows.h>
#   include <dbghelp.h>
#elif defined(Q_CC_GNU)
#   include <cxxabi.h>
#   include <execinfo.h>
#   include <cstring>
#endif

namespace BlackMisc
{

#if defined(QT_DEBUG)
    QStringList getStackTrace()
    {
        return getStackTraceAlways();
    }
#else
    QStringList getStackTrace()
    {
        return { "No stack trace with release build" };
    }
#endif

#if defined(Q_OS_WIN32)
    QStringList getStackTraceAlways()
    {
        static QMutex mutex;
        QMutexLocker lock(&mutex);

        static std::once_flag flag;
        std::call_once(flag, []
        {
            SymInitialize(GetCurrentProcess(), nullptr, true);
            std::atexit([] { SymCleanup(GetCurrentProcess()); });
        });

        auto process = GetCurrentProcess();
        SymRefreshModuleList(process);

        std::array<void*, 100> stack;
        auto frames = CaptureStackBackTrace(1, static_cast<DWORD>(stack.size()), stack.data(), nullptr);

        struct
        {
            SYMBOL_INFO info;
            std::array<char, 256> name;
        } symbol;
        symbol.info.MaxNameLen = static_cast<ULONG>(symbol.name.size() - 1);
        symbol.info.SizeOfStruct = sizeof(symbol.info);

        QStringList result;
        for (int i = 0; i < frames; ++i)
        {
            DWORD displacement = 0;
            IMAGEHLP_LINE64 line;
            line.SizeOfStruct = sizeof(line);
            SymFromAddr(process, reinterpret_cast<quintptr>(stack[i]), nullptr, &symbol.info);
            SymGetLineFromAddr64(process, reinterpret_cast<quintptr>(stack[i]), &displacement, &line);

            result.push_back(QLatin1String(symbol.info.Name) % u" line " % QString::number(line.LineNumber));
        }
        return result;
    }
#elif defined(Q_CC_GNU)
    QStringList getStackTraceAlways()
    {
        std::array<void*, 100> stack;
        auto frames = backtrace(stack.data(), stack.size());
        auto *symbols = backtrace_symbols(stack.data(), frames);

        QStringList result;
        char *demangled = nullptr;
        size_t size = 0;
        for (int i = 0; i < frames; ++i)
        {
            // Using C string functions to avoid unnecessary dynamic memory allocation
            auto *basename = std::strrchr(symbols[i], '/');
            if (! basename) { continue; }
            basename++;
            auto *symbol = std::strchr(basename, '(');
            if (! symbol) { continue; }
            auto *basenameEnd = symbol++;
            auto *end = std::strrchr(symbol, ')');
            if (! end) { continue; }
            auto *offset = std::strrchr(symbol, '+');
            auto *symbolEnd = offset ? offset++ : end;

            auto *temp = demangled; // avoid leaking memory if __cxa_demangle returns nullptr

            demangled = abi::__cxa_demangle(QByteArray(symbol, symbolEnd - symbol).constData(), demangled, &size, nullptr);

            if (demangled)
            {
                result.push_back(QLatin1String(demangled) % u' ' %
                                 u'(' % QLatin1String(basename, basenameEnd - basename) % u' ' % QLatin1String(symbol, end - symbol) % u')');
            }
            else
            {
                result.push_back(u'(' % QLatin1String(basename, basenameEnd - basename) % u' ' % QLatin1String(symbol, end - symbol) % u')');
                demangled = temp;
            }
        }
        free(symbols);
        free(demangled);
        return result;
    }
#else
    // cppcheck-suppress unusedFunction
    QStringList getStackTraceAlways()
    {
        return { "No stack trace on this platform" };
    }
#endif

}