/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the plugins of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Digia.  For licensing terms and
** conditions see http://qt.digia.com/licensing.  For further information
** use the contact form at http://qt.digia.com/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Digia gives you certain additional
** rights.  These rights are described in the Digia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include <QtCore/QtConfig>
#ifndef QT_NO_ACCESSIBILITY

#include "qwindowsmsaaaccessible.h"
#include "qwindowsaccessibility.h"
#include <oleacc.h>
#include <servprov.h>
#include <winuser.h>
#include "comutils.h"

#include <QtCore/qdebug.h>
#include <QtCore/qmap.h>
#include <QtCore/qpair.h>
#include <QtCore/qsettings.h>
#include <QtGui/qaccessible.h>
#include <QtGui/private/qaccessible2_p.h>
#include <QtGui/qguiapplication.h>
#include <qpa/qplatformnativeinterface.h>
#include <QtGui/qwindow.h>
#include <QtWidgets/qapplication.h>
#include <QtWidgets/qgraphicsitem.h>
#include <QtWidgets/qgraphicsview.h>
#include <QtWidgets/qmessagebox.h>

//#include <uiautomationcoreapi.h>
#ifndef UiaRootObjectId
#define UiaRootObjectId        -25
#endif

#if !defined(Q_CC_BOR) && !defined (Q_CC_GNU)
#include <comdef.h>
#endif


#include "../qtwindows_additional.h"


QT_BEGIN_NAMESPACE

class QWindowsEnumerate : public IEnumVARIANT
{
public:
    QWindowsEnumerate(const QVector<int> &a)
        : ref(0), current(0),array(a)
    {
    }

    virtual ~QWindowsEnumerate() {}

    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, LPVOID *);
    ULONG STDMETHODCALLTYPE AddRef();
    ULONG STDMETHODCALLTYPE Release();

    HRESULT STDMETHODCALLTYPE Clone(IEnumVARIANT **ppEnum);
    HRESULT STDMETHODCALLTYPE Next(unsigned long  celt, VARIANT FAR*  rgVar, unsigned long FAR*  pCeltFetched);
    HRESULT STDMETHODCALLTYPE Reset();
    HRESULT STDMETHODCALLTYPE Skip(unsigned long celt);

private:
    ULONG ref;
    ULONG current;
    QVector<int> array;
};

HRESULT STDMETHODCALLTYPE QWindowsEnumerate::QueryInterface(REFIID id, LPVOID *iface)
{
    *iface = 0;
    if (id == IID_IUnknown)
        *iface = (IUnknown*)this;
    else if (id == IID_IEnumVARIANT)
        *iface = (IEnumVARIANT*)this;

    if (*iface) {
        AddRef();
        return S_OK;
    }

    return E_NOINTERFACE;
}

ULONG STDMETHODCALLTYPE QWindowsEnumerate::AddRef()
{
    return ++ref;
}

ULONG STDMETHODCALLTYPE QWindowsEnumerate::Release()
{
    if (!--ref) {
        delete this;
        return 0;
    }
    return ref;
}

HRESULT STDMETHODCALLTYPE QWindowsEnumerate::Clone(IEnumVARIANT **ppEnum)
{
    QWindowsEnumerate *penum = 0;
    *ppEnum = 0;

    penum = new QWindowsEnumerate(array);
    if (!penum)
        return E_OUTOFMEMORY;
    penum->current = current;
    penum->array = array;
    penum->AddRef();
    *ppEnum = penum;

    return S_OK;
}

HRESULT STDMETHODCALLTYPE QWindowsEnumerate::Next(unsigned long  celt, VARIANT FAR*  rgVar, unsigned long FAR*  pCeltFetched)
{
    if (pCeltFetched)
        *pCeltFetched = 0;

    ULONG l;
    for (l = 0; l < celt; l++) {
        VariantInit(&rgVar[l]);
        if ((current+1) > (ULONG)array.size()) {
            *pCeltFetched = l;
            return S_FALSE;
        }

        rgVar[l].vt = VT_I4;
        rgVar[l].lVal = array[(int)current];
        ++current;
    }
    *pCeltFetched = l;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE QWindowsEnumerate::Reset()
{
    current = 0;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE QWindowsEnumerate::Skip(unsigned long celt)
{
    current += celt;
    if (current > (ULONG)array.size()) {
        current = array.size();
        return S_FALSE;
    }
    return S_OK;
}

#ifndef QT_NO_DEBUG
bool debug_accessibility()
{
    static int debugging = -1;
    if (debugging == -1)
        debugging = qgetenv("QT_DEBUG_ACCESSIBILITY").toInt();
    return !!debugging;
}
#endif

#if defined(DEBUG_SHOW_ATCLIENT_COMMANDS)
void accessibleDebugClientCalls_helper(const char* funcName, const QAccessibleInterface *iface)
{
    QString str;
    QDebug dbg(&str);
    dbg << iface << QLatin1String(funcName);
    accessibleDebug("%s", qPrintable(str));
}
#endif

/**************************************************************\
 *                                                             *
 *                        IUnknown                             *
 *                                                             *
 **************************************************************/
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::QueryInterface(REFIID id, LPVOID *iface)
{
    *iface = 0;

    QByteArray strIID = IIDToString(id);
    if (!strIID.isEmpty()) {
        QString ss;
        QDebug dbg(&ss);
        dbg << accessibleInterface();
        accessibleDebug("QWindowsIA2Accessible::QI() - IID:%s, iface:%s ", strIID.constData(), qPrintable(ss));
    }
    if (id == IID_IUnknown) {
        *iface = (IUnknown*)(IDispatch*)this;
    } else if (id == IID_IDispatch) {
        *iface = (IDispatch*)this;
    } else if (id == IID_IAccessible) {
        *iface = (IAccessible*)this;
    } else if (id == IID_IOleWindow) {
        *iface = (IOleWindow*)this;
    }

    if (*iface) {
        AddRef();
        return S_OK;
    }

    return E_NOINTERFACE;
}

ULONG STDMETHODCALLTYPE QWindowsMsaaAccessible::AddRef()
{
    return ++ref;
}

ULONG STDMETHODCALLTYPE QWindowsMsaaAccessible::Release()
{
    if (!--ref) {
        delete this;
        return 0;
    }
    return ref;
}


/*
  IDispatch
*/

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::GetTypeInfoCount(unsigned int * pctinfo)
{
    // We don't use a type library
    *pctinfo = 0;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::GetTypeInfo(unsigned int, unsigned long, ITypeInfo **pptinfo)
{
    // We don't use a type library
    *pptinfo = 0;
    return S_OK;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::GetIDsOfNames(const _GUID &, wchar_t **rgszNames, unsigned int, unsigned long, long *rgdispid)
{
#if !defined(Q_CC_BOR) && !defined(Q_CC_GNU)
    // PROPERTIES:  Hierarchical
    if (_bstr_t(rgszNames[0]) == _bstr_t(L"accParent"))
        rgdispid[0] = DISPID_ACC_PARENT;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accChildCount"))
        rgdispid[0] = DISPID_ACC_CHILDCOUNT;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accChild"))
        rgdispid[0] = DISPID_ACC_CHILD;

    // PROPERTIES:  Descriptional
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accName("))
        rgdispid[0] = DISPID_ACC_NAME;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accValue"))
        rgdispid[0] = DISPID_ACC_VALUE;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accDescription"))
        rgdispid[0] = DISPID_ACC_DESCRIPTION;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accRole"))
        rgdispid[0] = DISPID_ACC_ROLE;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accState"))
        rgdispid[0] = DISPID_ACC_STATE;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accHelp"))
        rgdispid[0] = DISPID_ACC_HELP;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accHelpTopic"))
        rgdispid[0] = DISPID_ACC_HELPTOPIC;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accKeyboardShortcut"))
        rgdispid[0] = DISPID_ACC_KEYBOARDSHORTCUT;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accFocus"))
        rgdispid[0] = DISPID_ACC_FOCUS;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accSelection"))
        rgdispid[0] = DISPID_ACC_SELECTION;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accDefaultAction"))
        rgdispid[0] = DISPID_ACC_DEFAULTACTION;

    // METHODS
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accSelect"))
        rgdispid[0] = DISPID_ACC_SELECT;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accLocation"))
        rgdispid[0] = DISPID_ACC_LOCATION;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accNavigate"))
        rgdispid[0] = DISPID_ACC_NAVIGATE;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accHitTest"))
        rgdispid[0] = DISPID_ACC_HITTEST;
    else if (_bstr_t(rgszNames[0]) == _bstr_t(L"accDoDefaultAction"))
        rgdispid[0] = DISPID_ACC_DODEFAULTACTION;
    else
        return DISP_E_UNKNOWNINTERFACE;

    return S_OK;
#else
    Q_UNUSED(rgszNames);
    Q_UNUSED(rgdispid);

    return DISP_E_MEMBERNOTFOUND;
#endif
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::Invoke(long dispIdMember,
                                                     const _GUID &,
                                                     unsigned long,
                                                     unsigned short wFlags,
                                                     tagDISPPARAMS *pDispParams,
                                                     tagVARIANT *pVarResult,
                                                     tagEXCEPINFO *, unsigned int *)
{
    HRESULT hr = DISP_E_MEMBERNOTFOUND;

    switch (dispIdMember)
    {
        case DISPID_ACC_PARENT:
            if (wFlags == DISPATCH_PROPERTYGET) {
                if (!pVarResult)
                    return E_INVALIDARG;
                hr = get_accParent(&pVarResult->pdispVal);
            } else {
                hr = DISP_E_MEMBERNOTFOUND;
            }
            break;

        case DISPID_ACC_CHILDCOUNT:
            if (wFlags == DISPATCH_PROPERTYGET) {
                if (!pVarResult)
                    return E_INVALIDARG;
                hr = get_accChildCount(&pVarResult->lVal);
            } else {
                hr = DISP_E_MEMBERNOTFOUND;
            }
            break;

        case DISPID_ACC_CHILD:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accChild(pDispParams->rgvarg[0], &pVarResult->pdispVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_NAME:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accName(pDispParams->rgvarg[0], &pVarResult->bstrVal);
            else if (wFlags == DISPATCH_PROPERTYPUT)
                hr = put_accName(pDispParams->rgvarg[0], pVarResult->bstrVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_VALUE:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accValue(pDispParams->rgvarg[0], &pVarResult->bstrVal);
            else if (wFlags == DISPATCH_PROPERTYPUT)
                hr = put_accValue(pDispParams->rgvarg[0], pVarResult->bstrVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_DESCRIPTION:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accDescription(pDispParams->rgvarg[0], &pVarResult->bstrVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_ROLE:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accRole(pDispParams->rgvarg[0], pVarResult);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_STATE:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accState(pDispParams->rgvarg[0], pVarResult);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_HELP:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accHelp(pDispParams->rgvarg[0], &pVarResult->bstrVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_HELPTOPIC:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accHelpTopic(&pDispParams->rgvarg[2].bstrVal, pDispParams->rgvarg[1], &pDispParams->rgvarg[0].lVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_KEYBOARDSHORTCUT:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accKeyboardShortcut(pDispParams->rgvarg[0], &pVarResult->bstrVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_FOCUS:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accFocus(pVarResult);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_SELECTION:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accSelection(pVarResult);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_DEFAULTACTION:
            if (wFlags == DISPATCH_PROPERTYGET)
                hr = get_accDefaultAction(pDispParams->rgvarg[0], &pVarResult->bstrVal);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_SELECT:
            if (wFlags == DISPATCH_METHOD)
                hr = accSelect(pDispParams->rgvarg[1].lVal, pDispParams->rgvarg[0]);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_LOCATION:
            if (wFlags == DISPATCH_METHOD)
                hr = accLocation(&pDispParams->rgvarg[4].lVal, &pDispParams->rgvarg[3].lVal, &pDispParams->rgvarg[2].lVal, &pDispParams->rgvarg[1].lVal, pDispParams->rgvarg[0]);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_NAVIGATE:
            if (wFlags == DISPATCH_METHOD)
                hr = accNavigate(pDispParams->rgvarg[1].lVal, pDispParams->rgvarg[0], pVarResult);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_HITTEST:
            if (wFlags == DISPATCH_METHOD)
                hr = accHitTest(pDispParams->rgvarg[1].lVal, pDispParams->rgvarg[0].lVal, pVarResult);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        case DISPID_ACC_DODEFAULTACTION:
            if (wFlags == DISPATCH_METHOD)
                hr = accDoDefaultAction(pDispParams->rgvarg[0]);
            else
                hr = DISP_E_MEMBERNOTFOUND;
            break;

        default:
            hr = DISP_E_MEMBERNOTFOUND;
            break;
    }

    if (!SUCCEEDED(hr)) {
        return hr;
    }
    return hr;
}

/*
  IAccessible

IAccessible::accHitTest documents the value returned in pvarID like this:

| *Point location*                                       | *vt member* | *Value member*          |
+========================================================+=============+=========================+
| Outside of the object's boundaries, and either inside  | VT_EMPTY    | None.                   |
| or outside of the object's bounding rectangle.         |             |                         |
+--------------------------------------------------------+-------------+-------------------------+
|  Within the object but not within a child element or a | VT_I4       | lVal is CHILDID_SELF    |
|  child object.                                         |             |                         |
+--------------------------------------------------------+-------------+-------------------------+
| Within a child element.                                | VT_I4       | lVal contains           |
|                                                        |             | the child ID.           |
+--------------------------------------------------------+-------------+-------------------------+
| Within a child object.                                 | VT_DISPATCH | pdispVal is set to the  |
|                                                        |             | child object's IDispatch|
|                                                        |             | interface pointer       |
+--------------------------------------------------------+-------------+-------------------------+
*/
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accHitTest(long xLeft, long yTop, VARIANT *pvarID)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QAccessibleInterface *child = accessible->childAt(xLeft, yTop);
    if (child == 0) {
        // no child found, return this item if it contains the coordinates
        if (accessible->rect().contains(xLeft, yTop)) {
            (*pvarID).vt = VT_I4;
            (*pvarID).lVal = CHILDID_SELF;
            return S_OK;
        }
    } else {
        IAccessible *iface = QWindowsAccessibility::wrap(child);
        if (iface) {
            (*pvarID).vt = VT_DISPATCH;
            (*pvarID).pdispVal = iface;
            return S_OK;
        }
    }

    // Did not find anything
    (*pvarID).vt = VT_EMPTY;
    return S_FALSE;
}

/*
 It is recommended to read
    "Implementing a Microsoft Active Accessibility (MSAA) Server.
    Practical Tips for Developers and How Mozilla Does It"
    (https://developer.mozilla.org/En/Accessibility/Implementing_an_MSAA_Server)

 to get an overview of what's important to implement and what parts of MSAA
 can be ignored. All stuff prefixed with "moz" are information from that page.
*/
// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accLocation(long *pxLeft, long *pyTop, long *pcxWidth, long *pcyHeight, VARIANT varID)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QAccessibleInterface *acc = childPointer(accessible, varID);
    if (!acc || !acc->isValid())
        return E_FAIL;
    const QRect rect = acc->rect();

    *pxLeft = rect.x();
    *pyTop = rect.y();
    *pcxWidth = rect.width();
    *pcyHeight = rect.height();

    return S_OK;
}

// moz: [important, but no need to implement up/down/left/right]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accNavigate(long navDir, VARIANT varStart, VARIANT *pvarEnd)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QAccessibleInterface *acc = 0;
    switch (navDir) {
    case NAVDIR_FIRSTCHILD:
        acc = accessible->child(0);
        break;
    case NAVDIR_LASTCHILD:
        acc = accessible->child(accessible->childCount() - 1);
        break;
    case NAVDIR_NEXT:
    case NAVDIR_PREVIOUS:
        if (!varStart.lVal){
            QAccessibleInterface *parent = accessible->parent();
            if (parent && parent->isValid()) {
                int index = parent->indexOfChild(accessible);
                index += (navDir == NAVDIR_NEXT) ? 1 : -1;
                if (index >= 0 && index < parent->childCount())
                    acc = parent->child(index);
            }
        } else {
            int index = varStart.lVal;
            index += (navDir == NAVDIR_NEXT) ? 1 : -1;
            if (index > 0 && index <= accessible->childCount())
                acc = accessible->child(index - 1);
        }
        break;

    // Geometrical
    case NAVDIR_UP:
    case NAVDIR_DOWN:
    case NAVDIR_LEFT:
    case NAVDIR_RIGHT: {
        QAccessibleInterface *pIface = accessible->parent();
        if (pIface && pIface->isValid()) {
            const int indexOfOurself = pIface->indexOfChild(accessible);
            QRect startg = accessible->rect();
            QPoint startc = startg.center();
            QAccessibleInterface *candidate = 0;
            unsigned mindist = UINT_MAX;    // will work on screen sizes at least up to 46340x46340
            const int sibCount = pIface->childCount();
            for (int i = 0; i < sibCount; ++i) {
                QAccessibleInterface *sibling = 0;
                sibling = pIface->child(i);
                Q_ASSERT(sibling);
                if (i == indexOfOurself || sibling->state().invisible) {
                    //ignore ourself and invisible siblings
                    continue;
                }

                QRect sibg = sibling->rect();
                QPoint sibc = sibg.center();
                QPoint sibp;
                QPoint startp;
                QPoint distp;
                switch (navDir) {
                case NAVDIR_LEFT:
                    startp = QPoint(startg.left(), startg.top() + startg.height() / 2);
                    sibp = QPoint(sibg.right(), sibg.top() + sibg.height() / 2);
                    if (QPoint(sibc - startc).x() >= 0) {
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                case NAVDIR_RIGHT:
                    startp = QPoint(startg.right(), startg.top() + startg.height() / 2);
                    sibp = QPoint(sibg.left(), sibg.top() + sibg.height() / 2);
                    if (QPoint(sibc - startc).x() <= 0) {
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                case NAVDIR_UP:
                    startp = QPoint(startg.left() + startg.width() / 2, startg.top());
                    sibp = QPoint(sibg.left() + sibg.width() / 2, sibg.bottom());
                    if (QPoint(sibc - startc).y() >= 0) {
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                case NAVDIR_DOWN:
                    startp = QPoint(startg.left() + startg.width() / 2, startg.bottom());
                    sibp = QPoint(sibg.left() + sibg.width() / 2, sibg.top());
                    if (QPoint(sibc - startc).y() <= 0) {
                        continue;
                    }
                    distp = sibp - startp;
                    break;
                default:
                    break;
                }

                // Since we're *comparing* (and not measuring) distances, we can compare the
                // squared distance, (thus, no need to take the sqrt()).
                unsigned dist = distp.x() * distp.x() + distp.y() * distp.y();
                if (dist < mindist) {
                    candidate = sibling;
                    mindist = dist;
                }
            }
            acc = candidate;
        }
    }
        break;
    default:
        break;
    }
    if (!acc) {
        (*pvarEnd).vt = VT_EMPTY;
        return S_FALSE;
    }

    if (IAccessible *iface = QWindowsAccessibility::wrap(acc)) {
        (*pvarEnd).vt = VT_DISPATCH;
        (*pvarEnd).pdispVal = iface;
        return S_OK;
    }

    (*pvarEnd).vt = VT_EMPTY;
    return S_FALSE;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accChild(VARIANT varChildID, IDispatch** ppdispChild)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    if (varChildID.vt != VT_I4)
        return E_INVALIDARG;

    QAccessibleInterface *acc = childPointer(accessible, varChildID);
    if (acc) {
        *ppdispChild = QWindowsAccessibility::wrap(acc);
        return S_OK;
    }

    return E_FAIL;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accChildCount(long* pcountChildren)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    *pcountChildren = accessible->childCount();
    return S_OK;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accParent(IDispatch** ppdispParent)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QAccessibleInterface *acc = accessible->parent();
    if (acc) {
        if (IAccessible *iface = QWindowsAccessibility::wrap(acc)) {
            *ppdispParent = iface;
            return S_OK;
        }
    }

    *ppdispParent = 0;
    return S_FALSE;
}

/*
  Properties and methods
*/
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accDoDefaultAction(VARIANT varID)
{
    Q_UNUSED(varID);
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    if (QAccessibleActionInterface *actionIface = accessible->actionInterface()) {
        const QString def = actionIface->actionNames().value(0);
        if (!def.isEmpty()) {
            actionIface->doAction(def);
            return S_OK;
        }
    }
    return S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accDefaultAction(VARIANT varID, BSTR* pszDefaultAction)
{
    Q_UNUSED(varID);
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    *pszDefaultAction = 0;
    if (QAccessibleActionInterface *actionIface = accessible->actionInterface()) {
        const QString def = actionIface->actionNames().value(0);
        if (!def.isEmpty())
            *pszDefaultAction = QStringToBSTR(def);
    }
    return *pszDefaultAction ? S_OK : S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accDescription(VARIANT varID, BSTR* pszDescription)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;


    QString descr;
    if (varID.lVal) {
        QAccessibleInterface *child = childPointer(accessible, varID);
        if (!child)
            return E_FAIL;
        descr = child->text(QAccessible::Description);
    } else {
        descr = accessible->text(QAccessible::Description);
    }
    if (descr.size()) {
        *pszDescription = QStringToBSTR(descr);
        return S_OK;
    }

    *pszDescription = 0;
    return S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accHelp(VARIANT varID, BSTR *pszHelp)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QString help;
    if (varID.lVal) {
        QAccessibleInterface *child = childPointer(accessible, varID);
        if (!child)
            return E_FAIL;
        help = child->text(QAccessible::Help);
    } else {
        help = accessible->text(QAccessible::Help);
    }
    if (help.size()) {
        *pszHelp = QStringToBSTR(help);
        return S_OK;
    }

    *pszHelp = 0;
    return S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accHelpTopic(BSTR *, VARIANT, long *)
{
    return DISP_E_MEMBERNOTFOUND;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accKeyboardShortcut(VARIANT varID, BSTR *pszKeyboardShortcut)
{
    Q_UNUSED(varID);
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    *pszKeyboardShortcut = 0;
    if (QAccessibleActionInterface *actionIface = accessible->actionInterface()) {
        const QString def = actionIface->actionNames().value(0);
        if (!def.isEmpty()) {
            const QString keyBoardShortCut = actionIface->keyBindingsForAction(def).value(0);
            if (!keyBoardShortCut.isEmpty())
                *pszKeyboardShortcut = QStringToBSTR(keyBoardShortCut);
        }
    }
    return *pszKeyboardShortcut ? S_OK : S_FALSE;
}

static QAccessibleInterface *relatedInterface(QAccessibleInterface *iface, QAccessible::RelationFlag flag)
{
    typedef QPair<QAccessibleInterface *, QAccessible::Relation> RelationPair;
    QVector<RelationPair> rels = iface->relations(flag);

    return rels.value(0).first;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accName(VARIANT varID, BSTR* pszName)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QString name;
    if (varID.lVal) {
        QAccessibleInterface *child = childPointer(accessible, varID);
        if (!child)
            return E_FAIL;
        name = child->text(QAccessible::Name);
        if (name.isEmpty()) {
            if (QAccessibleInterface *labelInterface = relatedInterface(child, QAccessible::Label)) {
                name = labelInterface->text(QAccessible::Name);
            }
        }
    } else {
        name = accessible->text(QAccessible::Name);
        if (name.isEmpty()) {
            if (QAccessibleInterface *labelInterface = relatedInterface(accessible, QAccessible::Label)) {
                name = labelInterface->text(QAccessible::Name);
            }
        }
    }
    if (name.size()) {
        *pszName = QStringToBSTR(name);
        return S_OK;
    }

    *pszName = 0;
    return S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::put_accName(VARIANT, BSTR)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    return DISP_E_MEMBERNOTFOUND;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accRole(VARIANT varID, VARIANT *pvarRole)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QAccessible::Role role;
    if (varID.lVal) {
        QAccessibleInterface *child = childPointer(accessible, varID);
        if (!child)
            return E_FAIL;
        role = child->role();
    } else {
        role = accessible->role();
    }

    if (role != QAccessible::NoRole) {
        if (role >= QAccessible::LayeredPane) {
            // This block should hopefully only be entered if the AT client
            // does not support IAccessible2, since it should prefer IA2::role() then.
            if (role == QAccessible::LayeredPane)
                role = QAccessible::Pane;
            else
                role = QAccessible::Client;
        }
        (*pvarRole).vt = VT_I4;
        (*pvarRole).lVal = role;
    } else {
        (*pvarRole).vt = VT_EMPTY;
    }
    return S_OK;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accState(VARIANT varID, VARIANT *pvarState)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QAccessible::State state;
    if (varID.lVal) {
        QAccessibleInterface *child = childPointer(accessible, varID);
        if (!child)
            return E_FAIL;
        state = child->state();
    } else {
        state = accessible->state();
    }

    LONG st = 0;
    if (state.animated)
        st |= STATE_SYSTEM_ANIMATED;
    if (state.busy)
        st |= STATE_SYSTEM_BUSY;
    if (state.checked)
        st |= STATE_SYSTEM_CHECKED;
    if (state.collapsed)
        st |= STATE_SYSTEM_COLLAPSED;
    if (state.defaultButton)
        st |= STATE_SYSTEM_DEFAULT;
    if (state.expanded)
        st |= STATE_SYSTEM_EXPANDED;
    if (state.extSelectable)
        st |= STATE_SYSTEM_EXTSELECTABLE;
    if (state.focusable)
        st |= STATE_SYSTEM_FOCUSABLE;
    if (state.focused)
        st |= STATE_SYSTEM_FOCUSED;
    if (state.hasPopup)
        st |= STATE_SYSTEM_HASPOPUP;
    if (state.hotTracked)
        st |= STATE_SYSTEM_HOTTRACKED;
    if (state.invisible)
        st |= STATE_SYSTEM_INVISIBLE;
    if (state.linked)
        st |= STATE_SYSTEM_LINKED;
    if (state.marqueed)
        st |= STATE_SYSTEM_MARQUEED;
    if (state.checkStateMixed)
        st |= STATE_SYSTEM_MIXED;
    if (state.movable)
        st |= STATE_SYSTEM_MOVEABLE;
    if (state.multiSelectable)
        st |= STATE_SYSTEM_MULTISELECTABLE;
    if (state.offscreen)
        st |= STATE_SYSTEM_OFFSCREEN;
    if (state.pressed)
        st |= STATE_SYSTEM_PRESSED;
    if (state.passwordEdit)
        st |= STATE_SYSTEM_PROTECTED;
    if (state.readOnly)
        st |= STATE_SYSTEM_READONLY;
    if (state.selectable)
        st |= STATE_SYSTEM_SELECTABLE;
    if (state.selected)
        st |= STATE_SYSTEM_SELECTED;
    if (state.selfVoicing)
        st |= STATE_SYSTEM_SELFVOICING;
    if (state.sizeable)
        st |= STATE_SYSTEM_SIZEABLE;
    if (state.traversed)
        st |= STATE_SYSTEM_TRAVERSED;

    (*pvarState).vt = VT_I4;
    (*pvarState).lVal = st;
    return S_OK;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accValue(VARIANT varID, BSTR* pszValue)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (varID.vt != VT_I4)
        return E_INVALIDARG;

    if (!accessible || !accessible->isValid() || varID.lVal) {
        return E_FAIL;
    }

    QString value;
    if (accessible->valueInterface()) {
        value = QString::number(accessible->valueInterface()->currentValue().toDouble());
    } else {
        value = accessible->text(QAccessible::Value);
    }
    if (!value.isNull()) {
        *pszValue = QStringToBSTR(value);
        return S_OK;
    }

    *pszValue = 0;
    accessibleDebug("return S_FALSE");
    return S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::put_accValue(VARIANT, BSTR)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    return DISP_E_MEMBERNOTFOUND;
}

// moz: [important]
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::accSelect(long flagsSelect, VARIANT varID)
{
    Q_UNUSED(flagsSelect);
    Q_UNUSED(varID);
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    bool res = false;

/*
  ### Check for accessibleTableInterface() or accessibleTextInterface()

  ### and if there are no ia2 interfaces we should do nothing??
    if (flagsSelect & SELFLAG_TAKEFOCUS)
        res = accessible()->doAction(SetFocus, varID.lVal, QVariantList());
    if (flagsSelect & SELFLAG_TAKESELECTION) {
        accessible()->doAction(ClearSelection, 0, QVariantList());
        res = accessible()->doAction(AddToSelection, varID.lVal, QVariantList());
    }
    if (flagsSelect & SELFLAG_EXTENDSELECTION)
        res = accessible()->doAction(ExtendSelection, varID.lVal, QVariantList());
    if (flagsSelect & SELFLAG_ADDSELECTION)
        res = accessible()->doAction(AddToSelection, varID.lVal, QVariantList());
    if (flagsSelect & SELFLAG_REMOVESELECTION)
        res = accessible()->doAction(RemoveSelection, varID.lVal, QVariantList());
*/
    return res ? S_OK : S_FALSE;
}

/*!
    \internal
    Can return:

  +-------------+------------------------------------------------------------------------------+
  | VT_EMPTY    | None. Neither this object nor any of its children has the keyboard focus.    |
  +-------------+------------------------------------------------------------------------------+
  | VT_I4       | lVal is CHILDID_SELF. The object itself has the keyboard focus.              |
  +-------------+------------------------------------------------------------------------------+
  | VT_I4       | lVal contains the child ID of the child element that has the keyboard focus. |
  +-------------+------------------------------------------------------------------------------+
  | VT_DISPATCH | pdispVal member is the address of the IDispatch interface for the child      |
  |             | object that has the keyboard focus.                                          |
  +-------------+------------------------------------------------------------------------------+
    moz: [important]
*/
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accFocus(VARIANT *pvarID)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    if (QAccessibleInterface *acc = accessible->focusChild()) {
        if (acc == accessible) {
            (*pvarID).vt = VT_I4;
            (*pvarID).lVal = CHILDID_SELF;
            return S_OK;
        } else {
            if (IAccessible *iface = QWindowsAccessibility::wrap(acc)) {
                (*pvarID).vt = VT_DISPATCH;
                (*pvarID).pdispVal = iface;
                return S_OK;
            }
        }
    }
    (*pvarID).vt = VT_EMPTY;
    return S_FALSE;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::get_accSelection(VARIANT *pvarChildren)
{
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    int cc = accessible->childCount();
    QVector<int> sel(cc);
    int selIndex = 0;
    for (int i = 0; i < cc; ++i) {
        bool isSelected = false;
        QAccessibleInterface *child = accessible->child(i);
        if (child) {
            isSelected = child->state().selected;
        }
        if (isSelected)
            sel[selIndex++] = i+1;
    }
    sel.resize(selIndex);
    if (sel.isEmpty()) {
        (*pvarChildren).vt = VT_EMPTY;
        return S_FALSE;
    }
    if (sel.size() == 1) {
        (*pvarChildren).vt = VT_I4;
        (*pvarChildren).lVal = sel[0];
        return S_OK;
    }
    IEnumVARIANT *iface = new QWindowsEnumerate(sel);
    IUnknown *uiface;
    iface->QueryInterface(IID_IUnknown, (void**)&uiface);
    (*pvarChildren).vt = VT_UNKNOWN;
    (*pvarChildren).punkVal = uiface;

    return S_OK;
}

/**************************************************************\
 *                         IOleWindow                          *
 **************************************************************/
HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::GetWindow(HWND *phwnd)
{
    *phwnd = 0;
    QAccessibleInterface *accessible = accessibleInterface();
    accessibleDebugClientCalls(accessible);
    if (!accessible)
        return E_FAIL;

    QWindow *window = QWindowsAccessibility::windowHelper(accessible);
    if (!window)
        return E_FAIL;

    QPlatformNativeInterface *platform = QGuiApplication::platformNativeInterface();
    Q_ASSERT(platform);
    *phwnd = (HWND)platform->nativeResourceForWindow("handle", window);
    accessibleDebug("QWindowsAccessible::GetWindow(): %p", *phwnd);
    return S_OK;
}

HRESULT STDMETHODCALLTYPE QWindowsMsaaAccessible::ContextSensitiveHelp(BOOL)
{
    return S_OK;
}

#define IF_EQUAL_RETURN_IIDSTRING(id, iid) if (id == iid) return QByteArray(#iid)
QByteArray QWindowsMsaaAccessible::IIDToString(REFIID id)
{
    IF_EQUAL_RETURN_IIDSTRING(id, IID_IUnknown);
    IF_EQUAL_RETURN_IIDSTRING(id, IID_IDispatch);
    IF_EQUAL_RETURN_IIDSTRING(id, IID_IAccessible);
    IF_EQUAL_RETURN_IIDSTRING(id, IID_IOleWindow);

    return QByteArray();
}

QT_END_NAMESPACE

#endif //QT_NO_ACCESSIBILITY
