/****************************************************************************
**
** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (developer.feedback@nokia.com)
**
** This file is part of the HbCore module of the UI Extensions for Mobile.
**
** GNU Lesser General Public License Usage
** 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, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at developer.feedback@nokia.com.
**
****************************************************************************/

#include "hbcontentwidget_p.h"
#include "hbmainwindow.h"
#include "hbmainwindow_p.h"
#include "hbview.h"
#include "hbeffectinternal_p.h"
#include "hbwidgetfeedback.h"
#include "hbscreen_p.h"
#include "hbscreenshotitem_p.h"
#include <QEvent>
#include <QGraphicsSceneMouseEvent>

/*!
  \class HbContentWidget

  \brief Container for views in a mainwindow. Extends HbStackedWidget with view
  switch effects and other features.

  \internal
*/

// An internal view switch flag, it is used to indicate the type of
// the effect (show/hide) to getEffectTarget.
const int Hiding = 0x1000000;

HbContentWidget::HbContentWidget(HbMainWindow *mainWindow, QGraphicsItem *parent /*= 0*/):
    HbStackedWidget(parent),
    mViewSwitchRunning(false),
    mTargetView(0),
    mHidingView(0),
    mMainWindow(mainWindow)
{
    // Do not defer this, it causes invalidation and updating.
    setFocusPolicy(Qt::StrongFocus);

    setAcceptTouchEvents(true);
}

QSizeF HbContentWidget::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const
{
    Q_UNUSED(constraint);

    QSizeF size;

    switch (which) {
    case Qt::MinimumSize:
        size = QSizeF(0, 0);
        break;

    case Qt::PreferredSize: {
        HbDeviceProfile profile(HbDeviceProfile::profile(this));
        size = profile.logicalSize();
        if (!size.isValid()) {
            size = QSizeF(1000, 1000);
        }
    }
    break;

    case Qt::MaximumSize:
    default:
        size = QSizeF(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
        break;
    }

    return size;
}

void HbContentWidget::setTargetView(HbView *view)
{
    mTargetView = view;
}

QString HbContentWidget::getEffectEvent(const char *baseName,
                                        Hb::ViewSwitchFlags flags,
                                        HbView *viewFrom,
                                        HbView *viewTo)
{
    QString event(baseName);
    if (flags & Hb::ViewSwitchUseAltEvent) {
        event.append(QLatin1String("_alt"));
    }
    bool backAnim = false;
    if (flags & Hb::ViewSwitchUseBackAnim) {
        backAnim = true;
    } else if (!(flags & Hb::ViewSwitchUseNormalAnim)) {
        // No view switch direction is explicitly specified, try to
        // guess from the context of the view switch, that is, the
        // ordering between the source and destination views (as there
        // is no other information available to us here).
        int fromIndex = indexOf(viewFrom);
        int toIndex = indexOf(viewTo);
        // If to > from use the baseName as it is (NormalAnim).
        // Otherwise add the suffix (BackAnim).
        if (toIndex < fromIndex) {
            backAnim = true;
        }
    }
    if (backAnim) {
        event.append(QLatin1String("_back"));
    }
    return event;
}

QGraphicsWidget *HbContentWidget::getEffectTarget(HbView *view, Hb::ViewSwitchFlags flags)
{
    // View switch effects ("show" and "hide") are always registered
    // for the HbView instance (not for its content widget). However
    // the graphics item to be animated may be something different
    // (the content widget, the "screen" item, etc.) so use the
    // special start() version from HbEffectInternal. Also, some views
    // may not have a content widget, in this case use the HbView as
    // the effect target.
    QGraphicsWidget *viewWidget = view->widget();
    QGraphicsWidget *effectTarget = viewWidget ? viewWidget : view;
    HbMainWindowPrivate *mwd = HbMainWindowPrivate::d_ptr(mMainWindow);
    if (flags & Hb::ViewSwitchFullScreen) {
        effectTarget = mwd->mClippingItem;
        if (!(flags & Hb::ViewSwitchSequential)) {
            // The Parallel+FullScreen combination does not make sense
            // (e.g. cannot animate the one and only titlebar
            // concurrently).
            qWarning("HbMainWindow: parallel fullscreen view switch is not supported");
            effectTarget = 0;
        }
    } else if (flags & Hb::ViewSwitchCachedFullScreen) {
        // This version supports sequential effects too, but in the
        // hiding case the effect must run on the special graphics
        // item that will show a screenshot of the mainwindow.
        if (flags & Hiding) {
            effectTarget = mwd->screenshotItem();
        } else {
            effectTarget = mwd->mClippingItem;
        }
    }
    return effectTarget;
}

/*!
  Callback for 'hide' effect.
*/
void HbContentWidget::hideEffectFinished(HbEffect::EffectStatus status)
{
    // Make sure the old view is hidden. The effect does this too due to
    // HideRegItemBeforeClearingEffect so no matter which comes first (clearing
    // of the effect or this notification), the item is hidden properly before
    // resetting the transform etc. and thus there is no flicker.
    mHidingView->setVisible(false);
    if (mViewSwitchFlags & Hb::ViewSwitchCachedFullScreen) {
        HbMainWindowPrivate *mwd = HbMainWindowPrivate::d_ptr(mMainWindow);
        mwd->screenshotItem()->releaseAndHide();
        if (mViewSwitchFlags & Hb::ViewSwitchSequential) {
            mwd->mClippingItem->show();
        }
    }
    // Start the "show" phase if not yet started.
    if (mViewSwitchFlags & Hb::ViewSwitchSequential) {
        // Do not show targetView yet, leave it to the effect in order to
        // prevent flickering.
        if (status.reason != Hb::EffectCancelled) {
            runViewSwitchEffectShow();
        } else {
            mTargetView->setVisible(true);
            viewSwitchEffectsFinished(status);
        }
    }
}

/*!
  Callback for 'show' effect.
*/
void HbContentWidget::viewSwitchEffectsFinished(HbEffect::EffectStatus status)
{
    Q_UNUSED(status);
    // Do not bother with item visibility here, the effect should manage it
    // properly because the ShowItemOnFirstUpdate flag was set.
    mViewSwitchRunning = false;
    mMainWindow->setInteractive(true); // enable input events
    if (HbMainWindowPrivate::d_ptr(mMainWindow)->mDelayedConstructionHandled) {
        HbMainWindowPrivate::d_ptr(mMainWindow)->_q_viewReady();
    }
}

/*!
  Starts the "hide" effect (the first phase of a view switch animation).
*/
void HbContentWidget::runViewSwitchEffectHide(HbView *viewToHide, Hb::ViewSwitchFlags flags)
{
    // Cancel all on-going effects. Relying on the cancel() calls made by the
    // start() functions would not be enough in all situations.
    HbEffectInternal::cancelAll(0, true); // ignore looping effects, those are not view switch effects and must not be stopped here
    mViewSwitchRunning = true;

    bool hideOld = false;
    if (flags & Hb::ViewSwitchCachedFullScreen) {
        // Take a screenshot (must be done before touching anything in the view
        // stack) and show it. The screenshot will effectively replace the
        // hiding view.
        HbMainWindowPrivate::d_ptr(mMainWindow)->screenshotItem()->takeAndShowScreenshot();
        hideOld = true;
    }

    // Make the new view the current one right away. This must be done asap to
    // prevent messed up state in mainwindow, the stack widget, etc. due to
    // events coming during the view switch animation.
    //
    // 2nd param (hideOld): We still want to see the old view (normally
    // setCurrentWidget would hide it), except in the cached case.
    //
    // 3rd param (showNew): The new view is not yet needed (the effect will take
    // care of making it visible).
    setCurrentWidget(mTargetView, hideOld, false);

    mHidingView = viewToHide;
    mViewSwitchFlags = flags;

    QGraphicsWidget *effectTarget = getEffectTarget(viewToHide, (Hb::ViewSwitchFlags) (flags | Hiding));
    if (effectTarget) {
        mMainWindow->setInteractive(false); // disable input while the effects are running
        if ((flags & Hb::ViewSwitchCachedFullScreen) && (flags & Hb::ViewSwitchSequential)) {
            // Get rid of decorators for the duration of the hide effect
            // otherwise they would show up under the screenshot item when
            // it disappears.
            HbMainWindowPrivate::d_ptr(mMainWindow)->mClippingItem->hide();
        }
        QString event = getEffectEvent("hide", flags, viewToHide, mTargetView);
        HbEffectInternal::EffectFlags effectFlags =
            HbEffectInternal::ClearEffectWhenFinished // the effect must not be persistent
            | HbEffectInternal::HideRegItemBeforeClearingEffect; // to prevent unlikely, but possible flicker
        HbEffectInternal::start(viewToHide, effectTarget, effectFlags,
                                "HB_view", event, this, "hideEffectFinished");
        if (!(flags & Hb::ViewSwitchSequential)) {
            runViewSwitchEffectShow();
        }
    }
}

/*!
  Starts the "show" effect. Must only be called from runViewSwitchEffectHide() or from
  the effect callback.
*/
void HbContentWidget::runViewSwitchEffectShow()
{
    QGraphicsWidget *effectTarget = getEffectTarget(mTargetView, mViewSwitchFlags);
    if (effectTarget) {
        QString event = getEffectEvent("show", mViewSwitchFlags, mHidingView, mTargetView);
        HbEffectInternal::EffectFlags effectFlags =
            HbEffectInternal::ClearEffectWhenFinished
            | HbEffectInternal::ShowItemOnFirstUpdate; // because targetView is not yet visible
        HbEffectInternal::start(mTargetView, effectTarget, effectFlags,
                                "HB_view", event, this, "viewSwitchEffectsFinished");
    }
}

void HbContentWidget::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    event->accept();
}

bool HbContentWidget::event(QEvent *event)
{
    if (event->type() == QEvent::Polish) {
        // No need for any real polishing.
        static_cast<HbWidgetPrivate *>(d_ptr)->polished = true;
        return true;
    } else if (event->type() == QEvent::TouchBegin) {
        // Accept all touch begin events to get the full Begin..End sequence
        event->accept();
        return true;
    }

    return HbWidget::event(event);
}