/*
  This file is part of KDDockWidgets.

  SPDX-FileCopyrightText: 2019-2021 Klarälvdalens Datakonsult AB, a KDAB Group company <info@kdab.com>
  Author: Sérgio Martins <sergio.martins@kdab.com>

  SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only

  Contact KDAB at <info@kdab.com> for commercial licensing options.
*/


/**
 * @file
 * @brief The MainWindow base class that's shared between QtWidgets and QtQuick stack
 *
 * @author Sérgio Martins \<sergio.martins@kdab.com\>
 */

#include "MainWindowBase.h"
#include "DockRegistry_p.h"
#include "DropArea_p.h"
#include "Frame_p.h"
#include "Utils_p.h"
#include "SideBar_p.h"
#include "Logging_p.h"
#include "Item_p.h"
#include "WidgetResizeHandler_p.h"
#include "FrameworkWidgetFactory.h"
#include "DropAreaWithCentralFrame_p.h"
#include "LayoutSaver_p.h"

using namespace KDDockWidgets;

class MainWindowBase::Private
{
public:
    explicit Private(MainWindowBase *mainWindow, MainWindowOptions options)
        : m_options(options)
        , q(mainWindow)
        , m_dropArea(new DropAreaWithCentralFrame(mainWindow, options))
    {
    }

    bool supportsCentralFrame() const
    {
        return m_options & MainWindowOption_HasCentralFrame;
    }

    WidgetResizeHandler::CursorPositions allowedResizeSides(SideBarLocation loc) const;

    QRect rectForOverlay(Frame *, SideBarLocation) const;
    SideBarLocation preferredSideBar(DockWidgetBase *) const;
    void updateOverlayGeometry(bool reusePreviousSize = false);
    void clearSideBars();

    QString name;
    QStringList affinities;
    const MainWindowOptions m_options;
    MainWindowBase *const q;
    QPointer<DockWidgetBase> m_overlayedDockWidget;
    DropAreaWithCentralFrame *const m_dropArea;
};

MainWindowBase::MainWindowBase(const QString &uniqueName, KDDockWidgets::MainWindowOptions options,
                               WidgetType *parent, Qt::WindowFlags flags)
    : QMainWindowOrQuick(parent, flags)
    , d(new Private(this, options))
{
    setUniqueName(uniqueName);
}

MainWindowBase::~MainWindowBase()
{
    DockRegistry::self()->unregisterMainWindow(this);
    delete d;
}

void MainWindowBase::addDockWidgetAsTab(DockWidgetBase *widget)
{
    Q_ASSERT(widget);
    qCDebug(addwidget) << Q_FUNC_INFO << widget;

    if (!DockRegistry::self()->affinitiesMatch(d->affinities, widget->affinities())) {
        qWarning() << Q_FUNC_INFO << "Refusing to dock widget with incompatible affinity."
                   << widget->affinities() << affinities();
        return;
    }

    if (widget->options() & DockWidgetBase::Option_NotDockable) {
        qWarning() << Q_FUNC_INFO << "Refusing to dock non-dockable widget" << widget;
        return;
    }

    if (d->supportsCentralFrame()) {
        dropArea()->m_centralFrame->addWidget(widget);
    } else {
        qWarning() << Q_FUNC_INFO << "Not supported without MainWindowOption_HasCentralFrame";
    }
}

void MainWindowBase::addDockWidget(DockWidgetBase *dw, Location location, DockWidgetBase *relativeTo, AddingOption option)
{
    if (dw->options() & DockWidgetBase::Option_NotDockable) {
        qWarning() << Q_FUNC_INFO << "Refusing to dock non-dockable widget" << dw;
        return;
    }

    dropArea()->addDockWidget(dw, location, relativeTo, option);
}

QString MainWindowBase::uniqueName() const
{
    return d->name;
}

MainWindowOptions MainWindowBase::options() const
{
    return d->m_options;
}

DropAreaWithCentralFrame *MainWindowBase::dropArea() const
{
    return d->m_dropArea;
}

MultiSplitter *MainWindowBase::multiSplitter() const
{
    return dropArea();
}

void MainWindowBase::setAffinities(const QStringList &affinityNames)
{
    QStringList affinities = affinityNames;
    affinities.removeAll(QString());

    if (d->affinities == affinities)
        return;

    if (!d->affinities.isEmpty()) {
        qWarning() << Q_FUNC_INFO
                   << "Affinity is already set, refusing to change."
                   << "Submit a feature request with a good justification.";
        return;
    }

    d->affinities = affinities;
}

QStringList MainWindowBase::affinities() const
{
    return d->affinities;
}

void MainWindowBase::layoutEqually()
{
    dropArea()->layoutEqually();
}

void MainWindowBase::layoutParentContainerEqually(DockWidgetBase *dockWidget)
{
    dropArea()->layoutParentContainerEqually(dockWidget);
}

WidgetResizeHandler::CursorPositions MainWindowBase::Private::allowedResizeSides(SideBarLocation loc) const
{
    // When a sidebar is on top, you can only resize its bottom.
    // and so forth...

    switch (loc) {
    case SideBarLocation::North:
        return WidgetResizeHandler::CursorPosition_Bottom;
    case SideBarLocation::East:
        return WidgetResizeHandler::CursorPosition_Left;
    case SideBarLocation::West:
        return WidgetResizeHandler::CursorPosition_Right;
    case SideBarLocation::South:
        return WidgetResizeHandler::CursorPosition_Top;
    case SideBarLocation::None:
        return WidgetResizeHandler::CursorPosition_Undefined;
    }

    return WidgetResizeHandler::CursorPosition_Undefined;
}

QRect MainWindowBase::Private::rectForOverlay(Frame *frame, SideBarLocation location) const
{
    SideBar *sb = q->sideBar(location);
    if (!sb)
        return {};

    const QRect centralAreaGeo = q->centralAreaGeometry();
    const QMargins centerWidgetMargins = q->centerWidgetMargins();

    QRect rect;
    const int margin = 1;
    switch (location) {
    case SideBarLocation::North:
    case SideBarLocation::South: {

        SideBar *leftSideBar = q->sideBar(SideBarLocation::West);
        SideBar *rightSideBar = q->sideBar(SideBarLocation::East);
        const int leftSideBarWidth = (leftSideBar && leftSideBar->isVisible()) ? leftSideBar->width()
                                                                               : 0;
        const int rightSideBarWidth = (rightSideBar && rightSideBar->isVisible()) ? rightSideBar->width()
                                                                                  : 0;
        rect.setHeight(qMax(300, frame->minSize().height()));
        rect.setWidth(centralAreaGeo.width() - margin * 2 - leftSideBarWidth - rightSideBarWidth);
        rect.moveLeft(margin + leftSideBarWidth);
        if (location == SideBarLocation::South) {
            rect.moveTop(centralAreaGeo.bottom() - centerWidgetMargins.bottom() - rect.height() - sb->height());
        } else {
            rect.moveTop(centralAreaGeo.y() + sb->height() + centerWidgetMargins.top());
        }
        break;
    }
    case SideBarLocation::West:
    case SideBarLocation::East: {
        SideBar *topSideBar = q->sideBar(SideBarLocation::North);
        SideBar *bottomSideBar = q->sideBar(SideBarLocation::South);
        const int topSideBarHeight = (topSideBar && topSideBar->isVisible()) ? topSideBar->height()
                                                                             : 0;
        const int bottomSideBarHeight = (bottomSideBar && bottomSideBar->isVisible()) ? bottomSideBar->height()
                                                                                      : 0;
        rect.setWidth(qMax(300, frame->minSize().width()));
        rect.setHeight(centralAreaGeo.height() - topSideBarHeight - bottomSideBarHeight - centerWidgetMargins.top() - centerWidgetMargins.bottom());
        rect.moveTop(sb->mapTo(q, QPoint(0, 0)).y() + topSideBarHeight - 1);
        if (location == SideBarLocation::East) {
            rect.moveLeft(centralAreaGeo.width() - rect.width() - sb->width() - centerWidgetMargins.right() - margin);
        } else {
            rect.moveLeft(margin + centralAreaGeo.x() + centerWidgetMargins.left() + sb->width());
        }

        break;
    }
    case SideBarLocation::None:
        break;
    }

    return rect;
}

static SideBarLocation opposedSideBarLocationForBorder(Layouting::Item::LayoutBorderLocation loc)
{
    switch (loc) {
    case Layouting::Item::LayoutBorderLocation_North:
        return SideBarLocation::South;
    case Layouting::Item::LayoutBorderLocation_East:
        return SideBarLocation::West;
    case Layouting::Item::LayoutBorderLocation_West:
        return SideBarLocation::East;
    case Layouting::Item::LayoutBorderLocation_South:
        return SideBarLocation::North;
    case Layouting::Item::LayoutBorderLocation_All:
    case Layouting::Item::LayoutBorderLocation_Verticals:
    case Layouting::Item::LayoutBorderLocation_Horizontals:
    case Layouting::Item::LayoutBorderLocation_None:
        break;
    }

    qWarning() << Q_FUNC_INFO << "Unknown loc" << loc;
    return SideBarLocation::None;
}

static SideBarLocation sideBarLocationForBorder(Layouting::Item::LayoutBorderLocations loc)
{
    switch (loc) {
    case Layouting::Item::LayoutBorderLocation_North:
        return SideBarLocation::North;
    case Layouting::Item::LayoutBorderLocation_East:
        return SideBarLocation::East;
    case Layouting::Item::LayoutBorderLocation_West:
        return SideBarLocation::West;
    case Layouting::Item::LayoutBorderLocation_South:
        return SideBarLocation::South;
    case Layouting::Item::LayoutBorderLocation_All:
    case Layouting::Item::LayoutBorderLocation_Verticals:
    case Layouting::Item::LayoutBorderLocation_Horizontals:
    case Layouting::Item::LayoutBorderLocation_None:
        break;
    }

    return SideBarLocation::None;
}

SideBarLocation MainWindowBase::Private::preferredSideBar(DockWidgetBase *dw) const
{
    // TODO: Algorithm can still be made smarter

    Layouting::Item *item = q->multiSplitter()->itemForFrame(dw->frame());
    if (!item) {
        qWarning() << Q_FUNC_INFO << "No item for dock widget";
        return SideBarLocation::None;
    }

    const Layouting::Item::LayoutBorderLocations borders = item->adjacentLayoutBorders();
    const qreal aspectRatio = dw->width() / (dw->height() * 1.0);

    /// 1. It's touching all borders
    if (borders == Layouting::Item::LayoutBorderLocation_All) {
        return aspectRatio > 1.0 ? SideBarLocation::South
                                 : SideBarLocation::East;
    }

    /// 2. It's touching 3 borders
    for (auto borderLoc : { Layouting::Item::LayoutBorderLocation_North, Layouting::Item::LayoutBorderLocation_East,
                            Layouting::Item::LayoutBorderLocation_West, Layouting::Item::LayoutBorderLocation_South }) {
        if (borders == (Layouting::Item::LayoutBorderLocation_All & ~borderLoc))
            return opposedSideBarLocationForBorder(borderLoc);
    }

    /// 3. It's touching left and right borders
    if ((borders & Layouting::Item::LayoutBorderLocation_Verticals) == Layouting::Item::LayoutBorderLocation_Verticals) {
        // We could measure the distance to the top though.
        return SideBarLocation::South;
    }

    /// 4. It's touching top and bottom borders
    if ((borders & Layouting::Item::LayoutBorderLocation_Horizontals) == Layouting::Item::LayoutBorderLocation_Horizontals) {
        // We could measure the distance to the left though.
        return SideBarLocation::East;
    }

    // 5. It's in a corner
    if (borders == (Layouting::Item::LayoutBorderLocation_West | Layouting::Item::LayoutBorderLocation_South)) {
        return aspectRatio > 1.0 ? SideBarLocation::South
                                 : SideBarLocation::West;
    } else if (borders == (Layouting::Item::LayoutBorderLocation_East | Layouting::Item::LayoutBorderLocation_South)) {
        return aspectRatio > 1.0 ? SideBarLocation::South
                                 : SideBarLocation::East;
    } else if (borders == (Layouting::Item::LayoutBorderLocation_West | Layouting::Item::LayoutBorderLocation_North)) {
        return aspectRatio > 1.0 ? SideBarLocation::North
                                 : SideBarLocation::West;
    } else if (borders == (Layouting::Item::LayoutBorderLocation_East | Layouting::Item::LayoutBorderLocation_North)) {
        return aspectRatio > 1.0 ? SideBarLocation::North
                                 : SideBarLocation::East;
    }


    {
        // 6. It's only touching 1 border
        SideBarLocation loc = sideBarLocationForBorder(borders);
        if (loc != SideBarLocation::None)
            return loc;
    }

    // It's not touching any border, use aspect ratio.
    return aspectRatio > 1.0 ? SideBarLocation::South
                             : SideBarLocation::West;
}

void MainWindowBase::Private::updateOverlayGeometry(bool reusePreviousSize)
{
    if (!m_overlayedDockWidget)
        return;

    SideBar *sb = q->sideBarForDockWidget(m_overlayedDockWidget);
    if (!sb) {
        qWarning() << Q_FUNC_INFO << "Expected a sidebar";
        return;
    }

    const QRect defaultGeometry = rectForOverlay(m_overlayedDockWidget->frame(), sb->location());
    QRect newGeometry = defaultGeometry;

    Frame *frame = m_overlayedDockWidget->frame();

    if (reusePreviousSize) {        
        // Let's try to honour the previous overlay size
        switch (sb->location()) {
        case SideBarLocation::North: {
            const int maxHeight = q->height() - frame->pos().y() - 10; // gap
            newGeometry.setHeight(qMin(frame->height(), maxHeight));
            break;
        }
        case SideBarLocation::South: {
            const int maxHeight = sb->pos().y() - m_dropArea->pos().y() - 10; // gap
            const int bottom = newGeometry.bottom();
            newGeometry.setHeight(qMin(frame->height(), maxHeight));
            newGeometry.moveBottom(bottom);
            break;
        }
        case SideBarLocation::East: {
            const int maxWidth = sb->pos().x() - m_dropArea->pos().x() - 10; // gap
            const int right = newGeometry.right();
            newGeometry.setWidth(qMin(frame->width(), maxWidth));
            newGeometry.moveRight(right);
            break;
        }
        case SideBarLocation::West: {
            const int maxWidth = q->width() - frame->pos().x() - 10; // gap
            newGeometry.setWidth(qMin(frame->height(), maxWidth));
            break;
        }
        case SideBarLocation::None:
            qWarning() << Q_FUNC_INFO << "Unexpected sidebar value";
            break;
        }

    }

    m_overlayedDockWidget->frame()->QWidgetAdapter::setGeometry(newGeometry);
}

void MainWindowBase::Private::clearSideBars()
{
    for (auto loc : { SideBarLocation::North, SideBarLocation::South,
                      SideBarLocation::East, SideBarLocation::West }) {
        if (SideBar *sb = q->sideBar(loc))
            sb->clear();
    }
}

void MainWindowBase::moveToSideBar(DockWidgetBase *dw)
{
    moveToSideBar(dw, d->preferredSideBar(dw));
}

void MainWindowBase::moveToSideBar(DockWidgetBase *dw, SideBarLocation location)
{
    if (SideBar *sb = sideBar(location)) {
        dw->forceClose();
        sb->addDockWidget(dw);
    } else {
        // Shouldn't happen
        qWarning() << Q_FUNC_INFO << "Minimization supported, probably disabled in Config::self().flags()";
    }
}

void MainWindowBase::restoreFromSideBar(DockWidgetBase *dw)
{
    // First un-overlay it, if it's overlayed
    if (dw == d->m_overlayedDockWidget)
        clearSideBarOverlay();

    SideBar *sb = sideBarForDockWidget(dw);
    if (!sb) {
        // Doesn't happen
        qWarning() << Q_FUNC_INFO << "Dock widget isn't in any sidebar";
        return;
    }

    sb->removeDockWidget(dw);
    dw->setFloating(false); // dock it
}

void MainWindowBase::overlayOnSideBar(DockWidgetBase *dw)
{
    if (!dw)
        return;

    const SideBar *sb = sideBarForDockWidget(dw);
    if (!sb) {
        qWarning() << Q_FUNC_INFO << "You need to add the dock widget to the sidebar before you can overlay it";
        return;
    }

    if (d->m_overlayedDockWidget == dw) {
        // Already overlayed
        return;
    }

    // We only support one overlay at a time, remove any existing overlay
    clearSideBarOverlay();

    auto frame = Config::self().frameworkWidgetFactory()->createFrame(this, FrameOption_IsOverlayed);
    d->m_overlayedDockWidget = dw;
    frame->addWidget(dw);
    d->updateOverlayGeometry(/*reusePreviousSize=*/ false);

    // Uncomment once I'm happy with the resizing
    auto resizeHandler = new WidgetResizeHandler(true, frame);
    resizeHandler->setAllowedResizeSides(d->allowedResizeSides(sb->location()));

    frame->QWidgetAdapter::show();

    Q_EMIT dw->isOverlayedChanged(true);
}

void MainWindowBase::toggleOverlayOnSideBar(DockWidgetBase *dw)
{
    const bool wasOverlayed = d->m_overlayedDockWidget == dw;
    clearSideBarOverlay(); // Because only 1 dock widget can be overlayed each time
    if (!wasOverlayed) {
        overlayOnSideBar(dw);
    }
}

void MainWindowBase::clearSideBarOverlay(bool deleteFrame)
{
    if (!d->m_overlayedDockWidget)
        return;

    Frame *frame = d->m_overlayedDockWidget->frame();
    frame->unoverlay();

    if (deleteFrame) {
        d->m_overlayedDockWidget->setParent(nullptr);
        Q_EMIT d->m_overlayedDockWidget->isOverlayedChanged(false);
        d->m_overlayedDockWidget = nullptr;
        delete frame;
    } else {
        // No cleanup, just unset. When we drag the overlay it becomes a normal floating window
        // meaning we reuse Frame. Don't delete it.
        Q_EMIT d->m_overlayedDockWidget->isOverlayedChanged(false);
        d->m_overlayedDockWidget = nullptr;
    }
}

SideBar *MainWindowBase::sideBarForDockWidget(const DockWidgetBase *dw) const
{
    for (auto loc : { SideBarLocation::North, SideBarLocation::South,
                      SideBarLocation::East, SideBarLocation::West }) {

        if (SideBar *sb = sideBar(loc)) {
            if (sb->containsDockWidget(const_cast<DockWidgetBase *>(dw)))
                return sb;
        }
    }

    return nullptr;
}

DockWidgetBase *MainWindowBase::overlayedDockWidget() const
{
    return d->m_overlayedDockWidget;
}

bool MainWindowBase::sideBarIsVisible(SideBarLocation loc) const
{
    if (SideBar *sb = sideBar(loc)) {
        return !sb->isEmpty(); // isVisible() is always true, but its height is 0 when empty.
    }

    return false;
}

bool MainWindowBase::anySideBarIsVisible() const
{
    for (auto loc : { SideBarLocation::North, SideBarLocation::South,
                      SideBarLocation::East, SideBarLocation::West }) {
        if (sideBarIsVisible(loc))
            return true;
    }

    return false;
}

void MainWindowBase::setUniqueName(const QString &uniqueName)
{
    if (uniqueName.isEmpty())
        return;

    if (d->name.isEmpty()) {
        d->name = uniqueName;
        Q_EMIT uniqueNameChanged();
        DockRegistry::self()->registerMainWindow(this);
    } else {
        qWarning() << Q_FUNC_INFO << "Already has a name." << this->uniqueName() << uniqueName;
    }
}

void MainWindowBase::onResized(QResizeEvent *)
{
    if (d->m_overlayedDockWidget)
        d->updateOverlayGeometry(/*reusePreviousSize=*/ true);
}

bool MainWindowBase::deserialize(const LayoutSaver::MainWindow &mw)
{
    if (mw.options != options()) {
        qWarning() << Q_FUNC_INFO << "Refusing to restore MainWindow with different options"
                   << "; expected=" << mw.options << "; has=" << options();
        return false;
    }

    if (d->affinities != mw.affinities) {
        qWarning() << Q_FUNC_INFO << "Affinty name changed from" << d->affinities
                   << "; to" << mw.affinities;

        d->affinities = mw.affinities;
    }

    const bool success = dropArea()->deserialize(mw.multiSplitterLayout);

    // Restore the SideBars
    d->clearSideBars();
    for (SideBarLocation loc : { SideBarLocation::North, SideBarLocation::East, SideBarLocation::West, SideBarLocation::South }) {
        SideBar *sb = sideBar(loc);
        if (!sb)
            continue;

        const QStringList dockWidgets = mw.dockWidgetsPerSideBar.value(loc);
        for (const QString &uniqueName : dockWidgets) {

            DockWidgetBase *dw = DockRegistry::self()->dockByName(uniqueName);
            if (!dw) {
                qWarning() << Q_FUNC_INFO << "Could not find dock widget" << uniqueName
                           << ". Won't restore it to sidebar";
                continue;
            }

            sb->addDockWidget(dw);
        }
    }

    // Commented-out for now, we dont' want to restore the popup/overlay. popups are perishable
    //if (!mw.overlayedDockWidget.isEmpty())
    //    overlayOnSideBar(DockRegistry::self()->dockByName(mw.overlayedDockWidget));

    return success;
}

LayoutSaver::MainWindow MainWindowBase::serialize() const
{
    LayoutSaver::MainWindow m;

    m.options = options();
    m.geometry = window()->geometry(); // window() as the MainWindow can be embedded
    m.isVisible = isVisible();
    m.uniqueName = uniqueName();
    m.screenIndex = screenNumberForWidget(this);
    m.screenSize = screenSizeForWidget(this);
    m.multiSplitterLayout = dropArea()->serialize();
    m.affinities = d->affinities;

    for (SideBarLocation loc : { SideBarLocation::North, SideBarLocation::East, SideBarLocation::West, SideBarLocation::South }) {
        if (SideBar *sb = sideBar(loc)) {
            const QStringList dockwidgets = sb->serialize();
            if (!dockwidgets.isEmpty())
                m.dockWidgetsPerSideBar.insert(loc, dockwidgets);
        }
    }

    return m;
}