// Copyright (C) 2020 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#ifndef QFUNCTIONS_WINRT_P_H
#define QFUNCTIONS_WINRT_P_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QtCore/private/qglobal_p.h>

#if defined(Q_OS_WIN) && defined(Q_CC_MSVC)

#include <QtCore/QCoreApplication>
#include <QtCore/QThread>
#include <QtCore/QAbstractEventDispatcher>
#include <QtCore/QElapsedTimer>
#include <QtCore/qt_windows.h>

#include <wrl.h>
#include <windows.foundation.h>

// Convenience macros for handling HRESULT values
#define RETURN_IF_FAILED(msg, ret) \
    if (FAILED(hr)) { \
        qErrnoWarning(hr, msg); \
        ret; \
    }

#define RETURN_IF_FAILED_WITH_ARGS(msg, ret, ...) \
    if (FAILED(hr)) { \
        qErrnoWarning(hr, msg, __VA_ARGS__); \
        ret; \
    }

#define RETURN_HR_IF_FAILED(msg) RETURN_IF_FAILED(msg, return hr)
#define RETURN_OK_IF_FAILED(msg) RETURN_IF_FAILED(msg, return S_OK)
#define RETURN_FALSE_IF_FAILED(msg) RETURN_IF_FAILED(msg, return false)
#define RETURN_VOID_IF_FAILED(msg) RETURN_IF_FAILED(msg, return)
#define RETURN_HR_IF_FAILED_WITH_ARGS(msg, ...) RETURN_IF_FAILED_WITH_ARGS(msg, return hr, __VA_ARGS__)
#define RETURN_OK_IF_FAILED_WITH_ARGS(msg, ...) RETURN_IF_FAILED_WITH_ARGS(msg, return S_OK, __VA_ARGS__)
#define RETURN_FALSE_IF_FAILED_WITH_ARGS(msg, ...) RETURN_IF_FAILED_WITH_ARGS(msg, return false, __VA_ARGS__)
#define RETURN_VOID_IF_FAILED_WITH_ARGS(msg, ...) RETURN_IF_FAILED_WITH_ARGS(msg, return, __VA_ARGS__)

#define Q_ASSERT_SUCCEEDED(hr) \
    Q_ASSERT_X(SUCCEEDED(hr), Q_FUNC_INFO, qPrintable(qt_error_string(hr)));

QT_BEGIN_NAMESPACE

namespace QWinRTFunctions {

// Synchronization methods
enum AwaitStyle
{
    YieldThread = 0,
    ProcessThreadEvents = 1,
    ProcessMainThreadEvents = 2
};

using EarlyExitConditionFunction = std::function<bool(void)>;

template<typename T>
static inline HRESULT _await_impl(const Microsoft::WRL::ComPtr<T> &asyncOp, AwaitStyle awaitStyle,
                                  uint timeout, EarlyExitConditionFunction func)
{
    Microsoft::WRL::ComPtr<ABI::Windows::Foundation::IAsyncInfo> asyncInfo;
    HRESULT hr = asyncOp.As(&asyncInfo);
    if (FAILED(hr))
        return hr;

    AsyncStatus status;
    QElapsedTimer t;
    if (timeout)
        t.start();
    switch (awaitStyle) {
    case ProcessMainThreadEvents:
        while (SUCCEEDED(hr = asyncInfo->get_Status(&status)) && status == AsyncStatus::Started) {
            QCoreApplication::processEvents();
            if (func && func())
                return E_ABORT;
            if (timeout && t.hasExpired(timeout))
                return HRESULT_FROM_WIN32(ERROR_TIMEOUT);
        }
        break;
    case ProcessThreadEvents:
        if (QAbstractEventDispatcher *dispatcher = QThread::currentThread()->eventDispatcher()) {
            while (SUCCEEDED(hr = asyncInfo->get_Status(&status)) && status == AsyncStatus::Started) {
                dispatcher->processEvents(QEventLoop::AllEvents);
                if (func && func())
                    return E_ABORT;
                if (timeout && t.hasExpired(timeout))
                    return HRESULT_FROM_WIN32(ERROR_TIMEOUT);
            }
            break;
        }
        // fall through
    default:
    case YieldThread:
        while (SUCCEEDED(hr = asyncInfo->get_Status(&status)) && status == AsyncStatus::Started) {
            QThread::yieldCurrentThread();
            if (timeout && t.hasExpired(timeout))
                return HRESULT_FROM_WIN32(ERROR_TIMEOUT);
        }
        break;
    }

    if (FAILED(hr) || status != AsyncStatus::Completed) {
        HRESULT ec;
        hr = asyncInfo->get_ErrorCode(&ec);
        if (FAILED(hr))
            return hr;
        hr = asyncInfo->Close();
        if (FAILED(hr))
            return hr;
        return ec;
    }

    return hr;
}

template<typename T>
static inline HRESULT await(const Microsoft::WRL::ComPtr<T> &asyncOp,
                            AwaitStyle awaitStyle = YieldThread, uint timeout = 0,
                            EarlyExitConditionFunction func = nullptr)
{
    HRESULT hr = _await_impl(asyncOp, awaitStyle, timeout, func);
    if (FAILED(hr))
        return hr;

    return asyncOp->GetResults();
}

template<typename T, typename U>
static inline HRESULT await(const Microsoft::WRL::ComPtr<T> &asyncOp, U *results,
                            AwaitStyle awaitStyle = YieldThread, uint timeout = 0,
                            EarlyExitConditionFunction func = nullptr)
{
    HRESULT hr = _await_impl(asyncOp, awaitStyle, timeout, func);
    if (FAILED(hr))
        return hr;

    return asyncOp->GetResults(results);
}

} // QWinRTFunctions

QT_END_NAMESPACE

#endif // Q_OS_WIN && Q_CC_MSVC

#endif // QFUNCTIONS_WINRT_P_H