/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

HWND juce_messageWindowHandle = 0;  // (this is used by other parts of the codebase)

void* getUser32Function (const char* functionName)
{
    HMODULE module = GetModuleHandleA ("user32.dll");
    jassert (module != 0);
    return (void*) GetProcAddress (module, functionName);
}

//==============================================================================
CriticalSection::CriticalSection() noexcept
{
    // (just to check the MS haven't changed this structure and broken things...)
    static_assert (sizeof (CRITICAL_SECTION) <= sizeof (lock),
                   "win32 lock array too small to hold CRITICAL_SECTION: please report this JUCE bug!");

    InitializeCriticalSection ((CRITICAL_SECTION*) lock);
}

CriticalSection::~CriticalSection() noexcept        { DeleteCriticalSection ((CRITICAL_SECTION*) lock); }
void CriticalSection::enter() const noexcept        { EnterCriticalSection ((CRITICAL_SECTION*) lock); }
bool CriticalSection::tryEnter() const noexcept     { return TryEnterCriticalSection ((CRITICAL_SECTION*) lock) != FALSE; }
void CriticalSection::exit() const noexcept         { LeaveCriticalSection ((CRITICAL_SECTION*) lock); }


//==============================================================================
WaitableEvent::WaitableEvent (const bool manualReset) noexcept
    : handle (CreateEvent (0, manualReset ? TRUE : FALSE, FALSE, 0)) {}

WaitableEvent::~WaitableEvent() noexcept        { CloseHandle (handle); }

void WaitableEvent::signal() const noexcept     { SetEvent (handle); }
void WaitableEvent::reset() const noexcept      { ResetEvent (handle); }

bool WaitableEvent::wait (const int timeOutMs) const noexcept
{
    return WaitForSingleObject (handle, (DWORD) timeOutMs) == WAIT_OBJECT_0;
}

//==============================================================================
void JUCE_API juce_threadEntryPoint (void*);

static unsigned int __stdcall threadEntryProc (void* userData)
{
    if (juce_messageWindowHandle != 0)
        AttachThreadInput (GetWindowThreadProcessId (juce_messageWindowHandle, 0),
                           GetCurrentThreadId(), TRUE);

    juce_threadEntryPoint (userData);

    _endthreadex (0);
    return 0;
}

void Thread::launchThread()
{
    unsigned int newThreadId;
    threadHandle = (void*) _beginthreadex (0, (unsigned int) threadStackSize,
                                           &threadEntryProc, this, 0, &newThreadId);
    threadId = (ThreadID) (pointer_sized_int) newThreadId;
}

void Thread::closeThreadHandle()
{
    CloseHandle ((HANDLE) threadHandle.get());
    threadId = 0;
    threadHandle = 0;
}

void Thread::killThread()
{
    if (threadHandle.get() != 0)
    {
       #if JUCE_DEBUG
        OutputDebugStringA ("** Warning - Forced thread termination **\n");
       #endif
        TerminateThread (threadHandle.get(), 0);
    }
}

void JUCE_CALLTYPE Thread::setCurrentThreadName (const String& name)
{
   #if JUCE_DEBUG && JUCE_MSVC
    struct
    {
        DWORD dwType;
        LPCSTR szName;
        DWORD dwThreadID;
        DWORD dwFlags;
    } info;

    info.dwType = 0x1000;
    info.szName = name.toUTF8();
    info.dwThreadID = GetCurrentThreadId();
    info.dwFlags = 0;

    __try
    {
        RaiseException (0x406d1388 /*MS_VC_EXCEPTION*/, 0, sizeof (info) / sizeof (ULONG_PTR), (ULONG_PTR*) &info);
    }
    __except (EXCEPTION_CONTINUE_EXECUTION)
    {}
   #else
    ignoreUnused (name);
   #endif
}

Thread::ThreadID JUCE_CALLTYPE Thread::getCurrentThreadId()
{
    return (ThreadID) (pointer_sized_int) GetCurrentThreadId();
}

bool Thread::setThreadPriority (void* handle, int priority)
{
    int pri = THREAD_PRIORITY_TIME_CRITICAL;

    if (priority < 1)       pri = THREAD_PRIORITY_IDLE;
    else if (priority < 2)  pri = THREAD_PRIORITY_LOWEST;
    else if (priority < 5)  pri = THREAD_PRIORITY_BELOW_NORMAL;
    else if (priority < 7)  pri = THREAD_PRIORITY_NORMAL;
    else if (priority < 9)  pri = THREAD_PRIORITY_ABOVE_NORMAL;
    else if (priority < 10) pri = THREAD_PRIORITY_HIGHEST;

    if (handle == 0)
        handle = GetCurrentThread();

    return SetThreadPriority (handle, pri) != FALSE;
}

void JUCE_CALLTYPE Thread::setCurrentThreadAffinityMask (const uint32 affinityMask)
{
    SetThreadAffinityMask (GetCurrentThread(), affinityMask);
}

//==============================================================================
struct SleepEvent
{
    SleepEvent() noexcept
        : handle (CreateEvent (nullptr, FALSE, FALSE,
                              #if JUCE_DEBUG
                               _T("JUCE Sleep Event")))
                              #else
                               nullptr))
                              #endif
    {}

    ~SleepEvent() noexcept
    {
        CloseHandle (handle);
        handle = 0;
    }

    HANDLE handle;
};

static SleepEvent sleepEvent;

void JUCE_CALLTYPE Thread::sleep (const int millisecs)
{
    jassert (millisecs >= 0);

    if (millisecs >= 10 || sleepEvent.handle == 0)
        Sleep ((DWORD) millisecs);
    else
        // unlike Sleep() this is guaranteed to return to the current thread after
        // the time expires, so we'll use this for short waits, which are more likely
        // to need to be accurate
        WaitForSingleObject (sleepEvent.handle, (DWORD) millisecs);
}

void Thread::yield()
{
    Sleep (0);
}

//==============================================================================
static int lastProcessPriority = -1;

// called when the app gains focus because Windows does weird things to process priority
// when you swap apps, and this forces an update when the app is brought to the front.
void juce_repeatLastProcessPriority()
{
    if (lastProcessPriority >= 0) // (avoid changing this if it's not been explicitly set by the app..)
    {
        DWORD p;

        switch (lastProcessPriority)
        {
            case Process::LowPriority:          p = IDLE_PRIORITY_CLASS; break;
            case Process::NormalPriority:       p = NORMAL_PRIORITY_CLASS; break;
            case Process::HighPriority:         p = HIGH_PRIORITY_CLASS; break;
            case Process::RealtimePriority:     p = REALTIME_PRIORITY_CLASS; break;
            default:                            jassertfalse; return; // bad priority value
        }

        SetPriorityClass (GetCurrentProcess(), p);
    }
}

void JUCE_CALLTYPE Process::setPriority (ProcessPriority prior)
{
    if (lastProcessPriority != (int) prior)
    {
        lastProcessPriority = (int) prior;
        juce_repeatLastProcessPriority();
    }
}

JUCE_API bool JUCE_CALLTYPE juce_isRunningUnderDebugger() noexcept
{
    return IsDebuggerPresent() != FALSE;
}

static void* currentModuleHandle = nullptr;

void* JUCE_CALLTYPE Process::getCurrentModuleInstanceHandle() noexcept
{
    if (currentModuleHandle == nullptr)
    {
        auto status = GetModuleHandleEx (GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
                                         (LPCTSTR) &currentModuleHandle,
                                         (HMODULE*) &currentModuleHandle);

        if (status == 0 || currentModuleHandle == nullptr)
            currentModuleHandle = GetModuleHandleA (nullptr);
    }

    return currentModuleHandle;
}

void JUCE_CALLTYPE Process::setCurrentModuleInstanceHandle (void* const newHandle) noexcept
{
    currentModuleHandle = newHandle;
}

void JUCE_CALLTYPE Process::raisePrivilege()
{
    jassertfalse; // xxx not implemented
}

void JUCE_CALLTYPE Process::lowerPrivilege()
{
    jassertfalse; // xxx not implemented
}

void JUCE_CALLTYPE Process::terminate()
{
   #if JUCE_MSVC && JUCE_CHECK_MEMORY_LEAKS
    _CrtDumpMemoryLeaks();
   #endif

    // bullet in the head in case there's a problem shutting down..
    ExitProcess (1);
}

bool juce_isRunningInWine()
{
    HMODULE ntdll = GetModuleHandleA ("ntdll");
    return ntdll != 0 && GetProcAddress (ntdll, "wine_get_version") != nullptr;
}

//==============================================================================
bool DynamicLibrary::open (const String& name)
{
    close();
    handle = LoadLibrary (name.toWideCharPointer());
    return handle != nullptr;
}

void DynamicLibrary::close()
{
    if (handle != nullptr)
    {
        FreeLibrary ((HMODULE) handle);
        handle = nullptr;
    }
}

void* DynamicLibrary::getFunction (const String& functionName) noexcept
{
    return handle != nullptr ? (void*) GetProcAddress ((HMODULE) handle, functionName.toUTF8()) // (void* cast is required for mingw)
                             : nullptr;
}


//==============================================================================
class InterProcessLock::Pimpl
{
public:
    Pimpl (String name, const int timeOutMillisecs)
        : handle (0), refCount (1)
    {
        name = name.replaceCharacter ('\\', '/');
        handle = CreateMutexW (0, TRUE, ("Global\\" + name).toWideCharPointer());

        // Not 100% sure why a global mutex sometimes can't be allocated, but if it fails, fall back to
        // a local one. (A local one also sometimes fails on other machines so neither type appears to be
        // universally reliable)
        if (handle == 0)
            handle = CreateMutexW (0, TRUE, ("Local\\" + name).toWideCharPointer());

        if (handle != 0 && GetLastError() == ERROR_ALREADY_EXISTS)
        {
            if (timeOutMillisecs == 0)
            {
                close();
                return;
            }

            switch (WaitForSingleObject (handle, timeOutMillisecs < 0 ? INFINITE : timeOutMillisecs))
            {
                case WAIT_OBJECT_0:
                case WAIT_ABANDONED:
                    break;

                case WAIT_TIMEOUT:
                default:
                    close();
                    break;
            }
        }
    }

    ~Pimpl()
    {
        close();
    }

    void close()
    {
        if (handle != 0)
        {
            ReleaseMutex (handle);
            CloseHandle (handle);
            handle = 0;
        }
    }

    HANDLE handle;
    int refCount;
};

InterProcessLock::InterProcessLock (const String& name_)
    : name (name_)
{
}

InterProcessLock::~InterProcessLock()
{
}

bool InterProcessLock::enter (const int timeOutMillisecs)
{
    const ScopedLock sl (lock);

    if (pimpl == nullptr)
    {
        pimpl.reset (new Pimpl (name, timeOutMillisecs));

        if (pimpl->handle == 0)
            pimpl.reset();
    }
    else
    {
        pimpl->refCount++;
    }

    return pimpl != nullptr;
}

void InterProcessLock::exit()
{
    const ScopedLock sl (lock);

    // Trying to release the lock too many times!
    jassert (pimpl != nullptr);

    if (pimpl != nullptr && --(pimpl->refCount) == 0)
        pimpl.reset();
}

//==============================================================================
class ChildProcess::ActiveProcess
{
public:
    ActiveProcess (const String& command, int streamFlags)
        : ok (false), readPipe (0), writePipe (0)
    {
        SECURITY_ATTRIBUTES securityAtts = { 0 };
        securityAtts.nLength = sizeof (securityAtts);
        securityAtts.bInheritHandle = TRUE;

        if (CreatePipe (&readPipe, &writePipe, &securityAtts, 0)
             && SetHandleInformation (readPipe, HANDLE_FLAG_INHERIT, 0))
        {
            STARTUPINFOW startupInfo = { 0 };
            startupInfo.cb = sizeof (startupInfo);

            startupInfo.hStdOutput = (streamFlags & wantStdOut) != 0 ? writePipe : 0;
            startupInfo.hStdError  = (streamFlags & wantStdErr) != 0 ? writePipe : 0;
            startupInfo.dwFlags = STARTF_USESTDHANDLES;

            ok = CreateProcess (nullptr, const_cast<LPWSTR> (command.toWideCharPointer()),
                                nullptr, nullptr, TRUE, CREATE_NO_WINDOW | CREATE_UNICODE_ENVIRONMENT,
                                nullptr, nullptr, &startupInfo, &processInfo) != FALSE;
        }
    }

    ~ActiveProcess()
    {
        if (ok)
        {
            CloseHandle (processInfo.hThread);
            CloseHandle (processInfo.hProcess);
        }

        if (readPipe != 0)
            CloseHandle (readPipe);

        if (writePipe != 0)
            CloseHandle (writePipe);
    }

    bool isRunning() const noexcept
    {
        return WaitForSingleObject (processInfo.hProcess, 0) != WAIT_OBJECT_0;
    }

    int read (void* dest, int numNeeded) const noexcept
    {
        int total = 0;

        while (ok && numNeeded > 0)
        {
            DWORD available = 0;

            if (! PeekNamedPipe ((HANDLE) readPipe, nullptr, 0, nullptr, &available, nullptr))
                break;

            const int numToDo = jmin ((int) available, numNeeded);

            if (available == 0)
            {
                if (! isRunning())
                    break;

                Thread::yield();
            }
            else
            {
                DWORD numRead = 0;
                if (! ReadFile ((HANDLE) readPipe, dest, numToDo, &numRead, nullptr))
                    break;

                total += numRead;
                dest = addBytesToPointer (dest, numRead);
                numNeeded -= numRead;
            }
        }

        return total;
    }

    bool killProcess() const noexcept
    {
        return TerminateProcess (processInfo.hProcess, 0) != FALSE;
    }

    uint32 getExitCode() const noexcept
    {
        DWORD exitCode = 0;
        GetExitCodeProcess (processInfo.hProcess, &exitCode);
        return (uint32) exitCode;
    }

    bool ok;

private:
    HANDLE readPipe, writePipe;
    PROCESS_INFORMATION processInfo;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ActiveProcess)
};

bool ChildProcess::start (const String& command, int streamFlags)
{
    activeProcess.reset (new ActiveProcess (command, streamFlags));

    if (! activeProcess->ok)
        activeProcess = nullptr;

    return activeProcess != nullptr;
}

bool ChildProcess::start (const StringArray& args, int streamFlags)
{
    String escaped;

    for (int i = 0; i < args.size(); ++i)
    {
        String arg (args[i]);

        // If there are spaces, surround it with quotes. If there are quotes,
        // replace them with \" so that CommandLineToArgv will correctly parse them.
        if (arg.containsAnyOf ("\" "))
            arg = arg.replace ("\"", "\\\"").quoted();

        escaped << arg << ' ';
    }

    return start (escaped.trim(), streamFlags);
}

//==============================================================================
struct HighResolutionTimer::Pimpl
{
    Pimpl (HighResolutionTimer& t) noexcept  : owner (t)
    {
    }

    ~Pimpl()
    {
        jassert (periodMs == 0);
    }

    void start (int newPeriod)
    {
        if (newPeriod != periodMs)
        {
            stop();
            periodMs = newPeriod;

            TIMECAPS tc;
            if (timeGetDevCaps (&tc, sizeof (tc)) == TIMERR_NOERROR)
            {
                const int actualPeriod = jlimit ((int) tc.wPeriodMin, (int) tc.wPeriodMax, newPeriod);

                timerID = timeSetEvent (actualPeriod, tc.wPeriodMin, callbackFunction, (DWORD_PTR) this,
                                        TIME_PERIODIC | TIME_CALLBACK_FUNCTION | 0x100 /*TIME_KILL_SYNCHRONOUS*/);
            }
        }
    }

    void stop()
    {
        periodMs = 0;
        timeKillEvent (timerID);
    }

    HighResolutionTimer& owner;
    int periodMs = 0;

private:
    unsigned int timerID;

    static void __stdcall callbackFunction (UINT, UINT, DWORD_PTR userInfo, DWORD_PTR, DWORD_PTR)
    {
        if (Pimpl* const timer = reinterpret_cast<Pimpl*> (userInfo))
            if (timer->periodMs != 0)
                timer->owner.hiResTimerCallback();
    }

    JUCE_DECLARE_NON_COPYABLE (Pimpl)
};

} // namespace juce
