/****************************************************************************
**
** Copyright (C) 2014 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
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** This file is part of the plugins of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
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** accordance with the commercial license agreement provided with the
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** following information to ensure the GNU Lesser General Public License
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**
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****************************************************************************/

#include "qfbscreen_p.h"
#include "qfbcursor_p.h"
#include "qfbwindow_p.h"
#include "qfbbackingstore_p.h"

#include <QtGui/QPainter>
#include <QtCore/QCoreApplication>
#include <qpa/qwindowsysteminterface.h>

#include <QtCore/QDebug>
#include <QtCore/QElapsedTimer>

QT_BEGIN_NAMESPACE

QFbScreen::QFbScreen() : mUpdatePending(false), mCursor(0), mGeometry(), mDepth(16), mFormat(QImage::Format_RGB16), mScreenImage(0), mCompositePainter(0), mIsUpToDate(false)
{
}

QFbScreen::~QFbScreen()
{
    delete mCompositePainter;
    delete mScreenImage;
}

void QFbScreen::initializeCompositor()
{
    mScreenImage = new QImage(mGeometry.size(), mFormat);
    scheduleUpdate();
}

bool QFbScreen::event(QEvent *event)
{
    if (event->type() == QEvent::UpdateRequest) {
        doRedraw();
        mUpdatePending = false;
        return true;
    }
    return QObject::event(event);
}

void QFbScreen::addWindow(QFbWindow *window)
{
    mWindowStack.prepend(window);
    if (!mBackingStores.isEmpty()) {
        //check if we have a backing store for this window
        for (int i = 0; i < mBackingStores.size(); ++i) {
            QFbBackingStore *bs = mBackingStores.at(i);
            // this gets called during QWindow::create() at a point where the
            // invariant (window->handle()->window() == window) is broken
            if (bs->window() == window->window()) {
                window->setBackingStore(bs);
                mBackingStores.removeAt(i);
                break;
            }
        }
    }
    invalidateRectCache();
    setDirty(window->geometry());
    QWindow *w = topWindow();
    QWindowSystemInterface::handleWindowActivated(w);
    topWindowChanged(w);
}

void QFbScreen::removeWindow(QFbWindow *window)
{
    mWindowStack.removeOne(window);
    invalidateRectCache();
    setDirty(window->geometry());
    QWindow *w = topWindow();
    QWindowSystemInterface::handleWindowActivated(w);
    topWindowChanged(w);
}

void QFbScreen::raise(QFbWindow *window)
{
    int index = mWindowStack.indexOf(window);
    if (index <= 0)
        return;
    mWindowStack.move(index, 0);
    invalidateRectCache();
    setDirty(window->geometry());
    QWindow *w = topWindow();
    QWindowSystemInterface::handleWindowActivated(w);
    topWindowChanged(w);
}

void QFbScreen::lower(QFbWindow *window)
{
    int index = mWindowStack.indexOf(window);
    if (index == -1 || index == (mWindowStack.size() - 1))
        return;
    mWindowStack.move(index, mWindowStack.size() - 1);
    invalidateRectCache();
    setDirty(window->geometry());
    QWindow *w = topWindow();
    QWindowSystemInterface::handleWindowActivated(w);
    topWindowChanged(w);
}

QWindow *QFbScreen::topWindow() const
{
    foreach (QFbWindow *fbw, mWindowStack)
        if (fbw->window()->type() == Qt::Window || fbw->window()->type() == Qt::Dialog)
            return fbw->window();
    return 0;
}

QWindow *QFbScreen::topLevelAt(const QPoint & p) const
{
    foreach (QFbWindow *fbw, mWindowStack) {
        if (fbw->geometry().contains(p, false) && fbw->window()->isVisible())
            return fbw->window();
    }
    return 0;
}

void QFbScreen::setDirty(const QRect &rect)
{
    QRect intersection = rect.intersected(mGeometry);
    QPoint screenOffset = mGeometry.topLeft();
    mRepaintRegion += intersection.translated(-screenOffset);    // global to local translation
    scheduleUpdate();
}

void QFbScreen::scheduleUpdate()
{
    if (!mUpdatePending) {
        mUpdatePending = true;
        QCoreApplication::postEvent(this, new QEvent(QEvent::UpdateRequest));
    }
}

void QFbScreen::setPhysicalSize(const QSize &size)
{
    mPhysicalSize = size;
}

void QFbScreen::setGeometry(const QRect &rect)
{
    delete mCompositePainter;
    mCompositePainter = 0;
    delete mScreenImage;
    mGeometry = rect;
    mScreenImage = new QImage(mGeometry.size(), mFormat);
    invalidateRectCache();
    QWindowSystemInterface::handleScreenGeometryChange(QPlatformScreen::screen(), geometry(), availableGeometry());
    resizeMaximizedWindows();
}

void QFbScreen::generateRects()
{
    mCachedRects.clear();
    QPoint screenOffset = mGeometry.topLeft();
    QRegion remainingScreen(mGeometry.translated(-screenOffset)); // global to local translation

    for (int i = 0; i < mWindowStack.length(); i++) {
        if (remainingScreen.isEmpty())
            break;
#if 0
        if (!mWindowStack[i]->isVisible())
            continue;
        if (mWindowStack[i]->isMinimized())
            continue;

        if (!mWindowStack[i]->testAttribute(Qt::WA_TranslucentBackground)) {
            QRect localGeometry = mWindowStack.at(i)->geometry().translated(-screenOffset); // global to local translation
            remainingScreen -= localGeometry;
            QRegion windowRegion(localGeometry);
            windowRegion -= remainingScreen;
            foreach (const QRect &rect, windowRegion.rects()) {
                mCachedRects += QPair<QRect, int>(rect, i);
            }
        }
#endif
    }
    foreach (const QRect &rect, remainingScreen.rects())
        mCachedRects += QPair<QRect, int>(rect, -1);
    mIsUpToDate = true;
    return;
}

QRegion QFbScreen::doRedraw()
{
    QPoint screenOffset = mGeometry.topLeft();

    QRegion touchedRegion;
    if (mCursor && mCursor->isDirty() && mCursor->isOnScreen()) {
        QRect lastCursor = mCursor->dirtyRect();
        mRepaintRegion += lastCursor;
    }
    if (mRepaintRegion.isEmpty() && (!mCursor || !mCursor->isDirty())) {
        return touchedRegion;
    }

    QVector<QRect> rects = mRepaintRegion.rects();

    if (!mIsUpToDate)
        generateRects();

    if (!mCompositePainter)
        mCompositePainter = new QPainter(mScreenImage);
    for (int rectIndex = 0; rectIndex < mRepaintRegion.rectCount(); rectIndex++) {
        QRegion rectRegion = rects[rectIndex];

        for (int i = 0; i < mCachedRects.length(); i++) {
            QRect screenSubRect = mCachedRects[i].first;
            int layer = mCachedRects[i].second;
            QRegion intersect = rectRegion.intersected(screenSubRect);

            if (intersect.isEmpty())
                continue;

            rectRegion -= intersect;

            // we only expect one rectangle, but defensive coding...
            foreach (const QRect &rect, intersect.rects()) {
                bool firstLayer = true;
                if (layer == -1) {
                    mCompositePainter->fillRect(rect, Qt::black);
                    firstLayer = false;
                    layer = mWindowStack.size() - 1;
                }

                for (int layerIndex = layer; layerIndex != -1; layerIndex--) {
                    if (!mWindowStack[layerIndex]->window()->isVisible())
                        continue;
                    // if (mWindowStack[layerIndex]->isMinimized())
                    //     continue;

                    QRect windowRect = mWindowStack[layerIndex]->geometry().translated(-screenOffset);
                    QRect windowIntersect = rect.translated(-windowRect.left(),
                                                            -windowRect.top());


                    QFbBackingStore *backingStore = mWindowStack[layerIndex]->backingStore();

                    if (backingStore) {
                        backingStore->lock();
                        mCompositePainter->drawImage(rect, backingStore->image(), windowIntersect);
                        backingStore->unlock();
                    }
                    if (firstLayer) {
                        firstLayer = false;
                    }
                }
            }
        }
    }

    QRect cursorRect;
    if (mCursor && (mCursor->isDirty() || mRepaintRegion.intersects(mCursor->lastPainted()))) {
        cursorRect = mCursor->drawCursor(*mCompositePainter);
        touchedRegion += cursorRect;
    }
    touchedRegion += mRepaintRegion;
    mRepaintRegion = QRegion();



//    qDebug() << "QFbScreen::doRedraw"  << mWindowStack.size() << mScreenImage->size() << touchedRegion;

    return touchedRegion;
}

QT_END_NAMESPACE

