// Copyright (C) 2016 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

#include "qttreepropertybrowser_p.h"

#include <QtCore/QOperatingSystemVersion>
#include <QtCore/QHash>
#include <QtGui/QFocusEvent>
#include <QtGui/QIcon>
#include <QtGui/QPainter>
#include <QtGui/QPalette>
#include <QtGui/QStyleHints>
#include <QtWidgets/QApplication>
#include <QtWidgets/QHBoxLayout>
#include <QtWidgets/QHeaderView>
#include <QtWidgets/QItemDelegate>
#include <QtWidgets/QStyle>
#include <QtWidgets/QTreeWidget>

QT_BEGIN_NAMESPACE

using namespace Qt::StringLiterals;

static constexpr bool isWindows = QOperatingSystemVersion::currentType() == QOperatingSystemVersion::Windows;

static inline bool isLightTheme()
{
    return QGuiApplication::styleHints()->colorScheme() != Qt::ColorScheme::Dark;
}

class QtPropertyEditorView;

class QtTreePropertyBrowserPrivate
{
    QtTreePropertyBrowser *q_ptr = nullptr;
    Q_DECLARE_PUBLIC(QtTreePropertyBrowser)

public:
    void init(QWidget *parent);

    void propertyInserted(QtBrowserItem *index, QtBrowserItem *afterIndex);
    void propertyRemoved(QtBrowserItem *index);
    void propertyChanged(QtBrowserItem *index);
    QWidget *createEditor(QtProperty *property, QWidget *parent) const
        { return q_ptr->createEditor(property, parent); }
    QtProperty *indexToProperty(const QModelIndex &index) const;
    QTreeWidgetItem *indexToItem(const QModelIndex &index) const;
    QtBrowserItem *indexToBrowserItem(const QModelIndex &index) const;
    bool lastColumn(int column) const;
    void disableItem(QTreeWidgetItem *item) const;
    void enableItem(QTreeWidgetItem *item) const;
    bool hasValue(QTreeWidgetItem *item) const;

    void slotCollapsed(const QModelIndex &index);
    void slotExpanded(const QModelIndex &index);

    QColor calculatedBackgroundColor(QtBrowserItem *item) const;

    QtPropertyEditorView *treeWidget() const { return m_treeWidget; }
    bool markPropertiesWithoutValue() const { return m_markPropertiesWithoutValue; }

    QtBrowserItem *currentItem() const;
    void setCurrentItem(QtBrowserItem *browserItem, bool block);
    void editItem(QtBrowserItem *browserItem);

    void slotCurrentBrowserItemChanged(QtBrowserItem *item);
    void slotCurrentTreeItemChanged(QTreeWidgetItem *newItem, QTreeWidgetItem *);

    QTreeWidgetItem *editedItem() const;

private:
    void updateItem(QTreeWidgetItem *item);

    QHash<QtBrowserItem *, QTreeWidgetItem *> m_indexToItem;
    QHash<QTreeWidgetItem *, QtBrowserItem *> m_itemToIndex;

    QHash<QtBrowserItem *, QColor> m_indexToBackgroundColor;

    QtPropertyEditorView *m_treeWidget = nullptr;

    bool m_headerVisible = true;
    QtTreePropertyBrowser::ResizeMode m_resizeMode = QtTreePropertyBrowser::Stretch;
    class QtPropertyEditorDelegate *m_delegate = nullptr;
    bool m_markPropertiesWithoutValue = false;
    bool m_browserChangedBlocked = false;
    QIcon m_expandIcon;
};

// ------------ QtPropertyEditorView
class QtPropertyEditorView : public QTreeWidget
{
    Q_OBJECT
public:
    QtPropertyEditorView(QWidget *parent = nullptr);

    void setEditorPrivate(QtTreePropertyBrowserPrivate *editorPrivate)
        { m_editorPrivate = editorPrivate; }

    QTreeWidgetItem *indexToItem(const QModelIndex &index) const
        { return itemFromIndex(index); }

protected:
    void keyPressEvent(QKeyEvent *event) override;
    void mousePressEvent(QMouseEvent *event) override;
    void drawRow(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override;

private:
    QtTreePropertyBrowserPrivate *m_editorPrivate = nullptr;
};

QtPropertyEditorView::QtPropertyEditorView(QWidget *parent) :
    QTreeWidget(parent)
{
    connect(header(), &QHeaderView::sectionDoubleClicked, this, &QTreeView::resizeColumnToContents);
}

void QtPropertyEditorView::drawRow(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    QStyleOptionViewItem opt = option;
    bool hasValue = true;
    if (m_editorPrivate) {
        QtProperty *property = m_editorPrivate->indexToProperty(index);
        if (property)
            hasValue = property->hasValue();
    }
    if (!hasValue && m_editorPrivate->markPropertiesWithoutValue()) {
        const QColor c = option.palette.color(QPalette::Dark);
        painter->fillRect(option.rect, c);
        opt.palette.setColor(QPalette::AlternateBase, c);
    } else {
        const QColor c = m_editorPrivate->calculatedBackgroundColor(m_editorPrivate->indexToBrowserItem(index));
        if (c.isValid()) {
            painter->fillRect(option.rect, c);
            opt.palette.setColor(QPalette::AlternateBase, c.lighter(112));
        }
    }
    QTreeWidget::drawRow(painter, opt, index);
    QColor color = static_cast<QRgb>(QApplication::style()->styleHint(QStyle::SH_Table_GridLineColor, &opt));
    painter->save();
    painter->setPen(QPen(color));
    painter->drawLine(opt.rect.x(), opt.rect.bottom(), opt.rect.right(), opt.rect.bottom());
    painter->restore();
}

void QtPropertyEditorView::keyPressEvent(QKeyEvent *event)
{
    switch (event->key()) {
    case Qt::Key_Return:
    case Qt::Key_Enter:
    case Qt::Key_Space: // Trigger Edit
        if (!m_editorPrivate->editedItem())
            if (const QTreeWidgetItem *item = currentItem())
                if (item->columnCount() >= 2 && ((item->flags() & (Qt::ItemIsEditable | Qt::ItemIsEnabled)) == (Qt::ItemIsEditable | Qt::ItemIsEnabled))) {
                    event->accept();
                    // If the current position is at column 0, move to 1.
                    QModelIndex index = currentIndex();
                    if (index.column() == 0) {
                        index = index.sibling(index.row(), 1);
                        setCurrentIndex(index);
                    }
                    edit(index);
                    return;
                }
        break;
    default:
        break;
    }
    QTreeWidget::keyPressEvent(event);
}

void QtPropertyEditorView::mousePressEvent(QMouseEvent *event)
{
    QTreeWidget::mousePressEvent(event);
    QTreeWidgetItem *item = itemAt(event->position().toPoint());

    if (item) {
        if ((item != m_editorPrivate->editedItem()) && (event->button() == Qt::LeftButton)
                && (header()->logicalIndexAt(event->position().toPoint().x()) == 1)
                && ((item->flags() & (Qt::ItemIsEditable | Qt::ItemIsEnabled)) == (Qt::ItemIsEditable | Qt::ItemIsEnabled))) {
            editItem(item, 1);
        } else if (!m_editorPrivate->hasValue(item) && m_editorPrivate->markPropertiesWithoutValue() && !rootIsDecorated()) {
            if (event->position().toPoint().x() + header()->offset() < 20)
                item->setExpanded(!item->isExpanded());
        }
    }
}

// ------------ QtPropertyEditorDelegate
class QtPropertyEditorDelegate : public QItemDelegate
{
    Q_OBJECT
public:
    using QItemDelegate::QItemDelegate;

    void setEditorPrivate(QtTreePropertyBrowserPrivate *editorPrivate)
        { m_editorPrivate = editorPrivate; }

    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option,
            const QModelIndex &index) const override;

    void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option,
            const QModelIndex &index) const override;

    void paint(QPainter *painter, const QStyleOptionViewItem &option,
            const QModelIndex &index) const override;

    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex &index) const override;

    void setModelData(QWidget *, QAbstractItemModel *,
            const QModelIndex &) const  override {}

    void setEditorData(QWidget *, const QModelIndex &) const override {}

    bool eventFilter(QObject *object, QEvent *event) override;
    void closeEditor(QtProperty *property);

    QTreeWidgetItem *editedItem() const { return m_editedItem; }

private slots:
    void slotEditorDestroyed(QObject *object);

private:
    int indentation(const QModelIndex &index) const;

    using EditorToPropertyMap = QHash<QWidget *, QtProperty *>;
    mutable EditorToPropertyMap m_editorToProperty;

    using PropertyToEditorMap = QHash<QtProperty *, QWidget *>;
    mutable PropertyToEditorMap m_propertyToEditor;
    QtTreePropertyBrowserPrivate *m_editorPrivate = nullptr;
    mutable QTreeWidgetItem *m_editedItem = nullptr;
    mutable QWidget *m_editedWidget = nullptr;
};

int QtPropertyEditorDelegate::indentation(const QModelIndex &index) const
{
    if (!m_editorPrivate)
        return 0;

    QTreeWidgetItem *item = m_editorPrivate->indexToItem(index);
    int indent = 0;
    while (item->parent()) {
        item = item->parent();
        ++indent;
    }
    if (m_editorPrivate->treeWidget()->rootIsDecorated())
        ++indent;
    return indent * m_editorPrivate->treeWidget()->indentation();
}

void QtPropertyEditorDelegate::slotEditorDestroyed(QObject *object)
{
    if (auto *w = qobject_cast<QWidget *>(object)) {
        const auto it = m_editorToProperty.find(w);
        if (it != m_editorToProperty.end()) {
            m_propertyToEditor.remove(it.value());
            m_editorToProperty.erase(it);
        }
        if (m_editedWidget == w) {
            m_editedWidget = nullptr;
            m_editedItem = nullptr;
        }
    }
}

void QtPropertyEditorDelegate::closeEditor(QtProperty *property)
{
    if (QWidget *w = m_propertyToEditor.value(property, nullptr))
        w->deleteLater();
}

QWidget *QtPropertyEditorDelegate::createEditor(QWidget *parent,
        const QStyleOptionViewItem &, const QModelIndex &index) const
{
    if (index.column() == 1 && m_editorPrivate) {
        QtProperty *property = m_editorPrivate->indexToProperty(index);
        QTreeWidgetItem *item = m_editorPrivate->indexToItem(index);
        if (property && item && (item->flags() & Qt::ItemIsEnabled)) {
            QWidget *editor = m_editorPrivate->createEditor(property, parent);
            if (editor) {
                editor->setAutoFillBackground(true);
                if (editor->palette().color(editor->backgroundRole()) == Qt::transparent)
                    editor->setBackgroundRole(QPalette::Window);
                editor->installEventFilter(const_cast<QtPropertyEditorDelegate *>(this));
                connect(editor, &QObject::destroyed,
                        this, &QtPropertyEditorDelegate::slotEditorDestroyed);
                m_propertyToEditor[property] = editor;
                m_editorToProperty[editor] = property;
                m_editedItem = item;
                m_editedWidget = editor;
            }
            return editor;
        }
    }
    return nullptr;
}

void QtPropertyEditorDelegate::updateEditorGeometry(QWidget *editor,
        const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    Q_UNUSED(index);
    editor->setGeometry(option.rect.adjusted(0, 0, 0, -1));
}

void QtPropertyEditorDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
            const QModelIndex &index) const
{
    bool hasValue = true;
    if (m_editorPrivate) {
        QtProperty *property = m_editorPrivate->indexToProperty(index);
        if (property)
            hasValue = property->hasValue();
    }
    QStyleOptionViewItem opt = option;
    if ((m_editorPrivate && index.column() == 0) || !hasValue) {
        QtProperty *property = m_editorPrivate->indexToProperty(index);
        if (property && property->isModified()) {
            opt.font.setBold(true);
            opt.fontMetrics = QFontMetrics(opt.font);
        }
    }
    QColor c;
    if (!hasValue && m_editorPrivate->markPropertiesWithoutValue()) {
        c = opt.palette.color(QPalette::Dark);
        // Hardcode "white" for Windows/light which is otherwise blue
        const QColor textColor = isWindows && isLightTheme()
            ? QColor(Qt::white) : opt.palette.color(QPalette::BrightText);
        opt.palette.setColor(QPalette::Text, textColor);
    } else {
        c = m_editorPrivate->calculatedBackgroundColor(m_editorPrivate->indexToBrowserItem(index));
        if (c.isValid() && (opt.features & QStyleOptionViewItem::Alternate))
            c = c.lighter(112);
    }
    if (c.isValid())
        painter->fillRect(option.rect, c);
    opt.state &= ~QStyle::State_HasFocus;
    QItemDelegate::paint(painter, opt, index);

    opt.palette.setCurrentColorGroup(QPalette::Active);
    QColor color = static_cast<QRgb>(QApplication::style()->styleHint(QStyle::SH_Table_GridLineColor, &opt));
    painter->save();
    painter->setPen(QPen(color));
    if (!m_editorPrivate || (!m_editorPrivate->lastColumn(index.column()) && hasValue)) {
        int right = (option.direction == Qt::LeftToRight) ? option.rect.right() : option.rect.left();
        painter->drawLine(right, option.rect.y(), right, option.rect.bottom());
    }
    painter->restore();
}

QSize QtPropertyEditorDelegate::sizeHint(const QStyleOptionViewItem &option,
            const QModelIndex &index) const
{
    return QItemDelegate::sizeHint(option, index) + QSize(3, 4);
}

bool QtPropertyEditorDelegate::eventFilter(QObject *object, QEvent *event)
{
    if (event->type() == QEvent::FocusOut) {
        QFocusEvent *fe = static_cast<QFocusEvent *>(event);
        if (fe->reason() == Qt::ActiveWindowFocusReason)
            return false;
    }
    return QItemDelegate::eventFilter(object, event);
}

//  -------- QtTreePropertyBrowserPrivate implementation

// Draw an icon indicating opened/closing branches
static QIcon drawIndicatorIcon(const QPalette &palette, QStyle *style)
{
    QPixmap pix(14, 14);
    pix.fill(Qt::transparent);
    QStyleOption branchOption;
    branchOption.rect = QRect(2, 2, 9, 9); // ### hardcoded in qcommonstyle.cpp
    branchOption.palette = palette;
    branchOption.state = QStyle::State_Children;

    QPainter p;
    // Draw closed state
    p.begin(&pix);
    style->drawPrimitive(QStyle::PE_IndicatorBranch, &branchOption, &p);
    p.end();
    QIcon rc = pix;
    rc.addPixmap(pix, QIcon::Selected, QIcon::Off);
    // Draw opened state
    branchOption.state |= QStyle::State_Open;
    pix.fill(Qt::transparent);
    p.begin(&pix);
    style->drawPrimitive(QStyle::PE_IndicatorBranch, &branchOption, &p);
    p.end();

    rc.addPixmap(pix, QIcon::Normal, QIcon::On);
    rc.addPixmap(pix, QIcon::Selected, QIcon::On);
    return rc;
}

void QtTreePropertyBrowserPrivate::init(QWidget *parent)
{
    auto *layout = new QHBoxLayout(parent);
    layout->setContentsMargins(QMargins());
    m_treeWidget = new QtPropertyEditorView(parent);
    m_treeWidget->setEditorPrivate(this);
    m_treeWidget->setIconSize(QSize(18, 18));
    layout->addWidget(m_treeWidget);

    m_treeWidget->setColumnCount(2);
    QStringList labels;
    labels.append(QCoreApplication::translate("QtTreePropertyBrowser", "Property"));
    labels.append(QCoreApplication::translate("QtTreePropertyBrowser", "Value"));
    m_treeWidget->setHeaderLabels(labels);
    m_treeWidget->setAlternatingRowColors(true);
    m_treeWidget->setEditTriggers(QAbstractItemView::EditKeyPressed);
    m_delegate = new QtPropertyEditorDelegate(parent);
    m_delegate->setEditorPrivate(this);
    m_treeWidget->setItemDelegate(m_delegate);
    m_treeWidget->header()->setSectionsMovable(false);
    m_treeWidget->header()->setSectionResizeMode(QHeaderView::Stretch);

    m_expandIcon = drawIndicatorIcon(q_ptr->palette(), q_ptr->style());

    QObject::connect(m_treeWidget, &QTreeView::collapsed,
                     q_ptr, [this](const QModelIndex &index) { slotCollapsed(index); });
    QObject::connect(m_treeWidget, &QTreeView::expanded,
                     q_ptr, [this](const QModelIndex &index) { slotExpanded(index); });
    QObject::connect(m_treeWidget, &QTreeWidget::currentItemChanged,
                     q_ptr, [this](QTreeWidgetItem *current, QTreeWidgetItem *previous)
                     { slotCurrentTreeItemChanged(current, previous); });
}

QtBrowserItem *QtTreePropertyBrowserPrivate::currentItem() const
{
    if (QTreeWidgetItem *treeItem = m_treeWidget->currentItem())
        return m_itemToIndex.value(treeItem);
    return nullptr;
}

void QtTreePropertyBrowserPrivate::setCurrentItem(QtBrowserItem *browserItem, bool block)
{
    const bool blocked = block ? m_treeWidget->blockSignals(true) : false;
    if (browserItem == nullptr)
        m_treeWidget->setCurrentItem(nullptr);
    else
        m_treeWidget->setCurrentItem(m_indexToItem.value(browserItem));
    if (block)
        m_treeWidget->blockSignals(blocked);
}

QtProperty *QtTreePropertyBrowserPrivate::indexToProperty(const QModelIndex &index) const
{
    QTreeWidgetItem *item = m_treeWidget->indexToItem(index);
    QtBrowserItem *idx = m_itemToIndex.value(item);
    if (idx)
        return idx->property();
    return nullptr;
}

QtBrowserItem *QtTreePropertyBrowserPrivate::indexToBrowserItem(const QModelIndex &index) const
{
    QTreeWidgetItem *item = m_treeWidget->indexToItem(index);
    return m_itemToIndex.value(item);
}

QTreeWidgetItem *QtTreePropertyBrowserPrivate::indexToItem(const QModelIndex &index) const
{
    return m_treeWidget->indexToItem(index);
}

bool QtTreePropertyBrowserPrivate::lastColumn(int column) const
{
    return m_treeWidget->header()->visualIndex(column) == m_treeWidget->columnCount() - 1;
}

void QtTreePropertyBrowserPrivate::disableItem(QTreeWidgetItem *item) const
{
    Qt::ItemFlags flags = item->flags();
    if (flags & Qt::ItemIsEnabled) {
        flags &= ~Qt::ItemIsEnabled;
        item->setFlags(flags);
        m_delegate->closeEditor(m_itemToIndex[item]->property());
        const int childCount = item->childCount();
        for (int i = 0; i < childCount; i++) {
            QTreeWidgetItem *child = item->child(i);
            disableItem(child);
        }
    }
}

void QtTreePropertyBrowserPrivate::enableItem(QTreeWidgetItem *item) const
{
    Qt::ItemFlags flags = item->flags();
    flags |= Qt::ItemIsEnabled;
    item->setFlags(flags);
    const int childCount = item->childCount();
    for (int i = 0; i < childCount; i++) {
        QTreeWidgetItem *child = item->child(i);
        QtProperty *property = m_itemToIndex[child]->property();
        if (property->isEnabled()) {
            enableItem(child);
        }
    }
}

bool QtTreePropertyBrowserPrivate::hasValue(QTreeWidgetItem *item) const
{
    QtBrowserItem *browserItem = m_itemToIndex.value(item);
    if (browserItem)
        return browserItem->property()->hasValue();
    return false;
}

void QtTreePropertyBrowserPrivate::propertyInserted(QtBrowserItem *index, QtBrowserItem *afterIndex)
{
    QTreeWidgetItem *afterItem = m_indexToItem.value(afterIndex);
    QTreeWidgetItem *parentItem = m_indexToItem.value(index->parent());

    QTreeWidgetItem *newItem = nullptr;
    if (parentItem) {
        newItem = new QTreeWidgetItem(parentItem, afterItem);
    } else {
        newItem = new QTreeWidgetItem(m_treeWidget, afterItem);
    }
    m_itemToIndex[newItem] = index;
    m_indexToItem[index] = newItem;

    newItem->setFlags(newItem->flags() | Qt::ItemIsEditable);
    newItem->setExpanded(true);

    updateItem(newItem);
}

void QtTreePropertyBrowserPrivate::propertyRemoved(QtBrowserItem *index)
{
    QTreeWidgetItem *item = m_indexToItem.value(index);

    if (m_treeWidget->currentItem() == item) {
        m_treeWidget->setCurrentItem(nullptr);
    }

    delete item;

    m_indexToItem.remove(index);
    m_itemToIndex.remove(item);
    m_indexToBackgroundColor.remove(index);
}

void QtTreePropertyBrowserPrivate::propertyChanged(QtBrowserItem *index)
{
    QTreeWidgetItem *item = m_indexToItem.value(index);

    updateItem(item);
}

void QtTreePropertyBrowserPrivate::updateItem(QTreeWidgetItem *item)
{
    QtProperty *property = m_itemToIndex[item]->property();
    QIcon expandIcon;
    if (property->hasValue()) {
        const QString valueToolTip = property->valueToolTip();
        const QString valueText = property->valueText();
        item->setToolTip(1, valueToolTip.isEmpty() ? valueText : valueToolTip);
        item->setIcon(1, property->valueIcon());
        item->setText(1, valueText);
    } else if (markPropertiesWithoutValue() && !m_treeWidget->rootIsDecorated()) {
        expandIcon = m_expandIcon;
    }
    item->setIcon(0, expandIcon);
    item->setFirstColumnSpanned(!property->hasValue());
    const QString descriptionToolTip  = property->descriptionToolTip();
    const QString propertyName = property->propertyName();
    item->setToolTip(0, descriptionToolTip.isEmpty() ? propertyName : descriptionToolTip);
    item->setStatusTip(0, property->statusTip());
    item->setWhatsThis(0, property->whatsThis());
    item->setText(0, propertyName);
    bool wasEnabled = item->flags() & Qt::ItemIsEnabled;
    bool isEnabled = wasEnabled;
    if (property->isEnabled()) {
        QTreeWidgetItem *parent = item->parent();
        isEnabled = !parent || (parent->flags() & Qt::ItemIsEnabled);
    } else {
        isEnabled = false;
    }
    if (wasEnabled != isEnabled) {
        if (isEnabled)
            enableItem(item);
        else
            disableItem(item);
    }
    m_treeWidget->viewport()->update();
}

QColor QtTreePropertyBrowserPrivate::calculatedBackgroundColor(QtBrowserItem *item) const
{
    QtBrowserItem *i = item;
    const auto itEnd = m_indexToBackgroundColor.constEnd();
    while (i) {
        auto it = m_indexToBackgroundColor.constFind(i);
        if (it != itEnd)
            return it.value();
        i = i->parent();
    }
    return {};
}

void QtTreePropertyBrowserPrivate::slotCollapsed(const QModelIndex &index)
{
    QTreeWidgetItem *item = indexToItem(index);
    QtBrowserItem *idx = m_itemToIndex.value(item);
    if (item)
        emit q_ptr->collapsed(idx);
}

void QtTreePropertyBrowserPrivate::slotExpanded(const QModelIndex &index)
{
    QTreeWidgetItem *item = indexToItem(index);
    QtBrowserItem *idx = m_itemToIndex.value(item);
    if (item)
        emit q_ptr->expanded(idx);
}

void QtTreePropertyBrowserPrivate::slotCurrentBrowserItemChanged(QtBrowserItem *item)
{
    if (!m_browserChangedBlocked && item != currentItem())
        setCurrentItem(item, true);
}

void QtTreePropertyBrowserPrivate::slotCurrentTreeItemChanged(QTreeWidgetItem *newItem, QTreeWidgetItem *)
{
    QtBrowserItem *browserItem = newItem ? m_itemToIndex.value(newItem) : 0;
    m_browserChangedBlocked = true;
    q_ptr->setCurrentItem(browserItem);
    m_browserChangedBlocked = false;
}

QTreeWidgetItem *QtTreePropertyBrowserPrivate::editedItem() const
{
    return m_delegate->editedItem();
}

void QtTreePropertyBrowserPrivate::editItem(QtBrowserItem *browserItem)
{
    if (QTreeWidgetItem *treeItem = m_indexToItem.value(browserItem, nullptr)) {
        m_treeWidget->setCurrentItem (treeItem, 1);
        m_treeWidget->editItem(treeItem, 1);
    }
}

/*!
    \class QtTreePropertyBrowser
    \internal
    \inmodule QtDesigner
    \since 4.4

    \brief The QtTreePropertyBrowser class provides QTreeWidget based
    property browser.

    A property browser is a widget that enables the user to edit a
    given set of properties. Each property is represented by a label
    specifying the property's name, and an editing widget (e.g. a line
    edit or a combobox) holding its value. A property can have zero or
    more subproperties.

    QtTreePropertyBrowser provides a tree based view for all nested
    properties, i.e. properties that have subproperties can be in an
    expanded (subproperties are visible) or collapsed (subproperties
    are hidden) state. For example:

    \image qttreepropertybrowser.png

    Use the QtAbstractPropertyBrowser API to add, insert and remove
    properties from an instance of the QtTreePropertyBrowser class.
    The properties themselves are created and managed by
    implementations of the QtAbstractPropertyManager class.

    \sa QtGroupBoxPropertyBrowser, QtAbstractPropertyBrowser
*/

/*!
    \fn void QtTreePropertyBrowser::collapsed(QtBrowserItem *item)

    This signal is emitted when the \a item is collapsed.

    \sa expanded(), setExpanded()
*/

/*!
    \fn void QtTreePropertyBrowser::expanded(QtBrowserItem *item)

    This signal is emitted when the \a item is expanded.

    \sa collapsed(), setExpanded()
*/

/*!
    Creates a property browser with the given \a parent.
*/
QtTreePropertyBrowser::QtTreePropertyBrowser(QWidget *parent)
    : QtAbstractPropertyBrowser(parent), d_ptr(new QtTreePropertyBrowserPrivate)
{
    d_ptr->q_ptr = this;

    d_ptr->init(this);
    QObject::connect(this, &QtAbstractPropertyBrowser::currentItemChanged,
                     this, [this](QtBrowserItem *current)
                     { d_ptr->slotCurrentBrowserItemChanged(current); });
}

/*!
    Destroys this property browser.

    Note that the properties that were inserted into this browser are
    \e not destroyed since they may still be used in other
    browsers. The properties are owned by the manager that created
    them.

    \sa QtProperty, QtAbstractPropertyManager
*/
QtTreePropertyBrowser::~QtTreePropertyBrowser() = default;

/*!
    \property QtTreePropertyBrowser::indentation
    \brief indentation of the items in the tree view.
*/
int QtTreePropertyBrowser::indentation() const
{
    return d_ptr->m_treeWidget->indentation();
}

void QtTreePropertyBrowser::setIndentation(int i)
{
    d_ptr->m_treeWidget->setIndentation(i);
}

/*!
  \property QtTreePropertyBrowser::rootIsDecorated
  \brief whether to show controls for expanding and collapsing root items.
*/
bool QtTreePropertyBrowser::rootIsDecorated() const
{
    return d_ptr->m_treeWidget->rootIsDecorated();
}

void QtTreePropertyBrowser::setRootIsDecorated(bool show)
{
    d_ptr->m_treeWidget->setRootIsDecorated(show);
    for (auto it = d_ptr->m_itemToIndex.cbegin(), end = d_ptr->m_itemToIndex.cend(); it != end; ++it) {
        QtProperty *property = it.value()->property();
        if (!property->hasValue())
            d_ptr->updateItem(it.key());
    }
}

/*!
  \property QtTreePropertyBrowser::alternatingRowColors
  \brief whether to draw the background using alternating colors.
  By default this property is set to true.
*/
bool QtTreePropertyBrowser::alternatingRowColors() const
{
    return d_ptr->m_treeWidget->alternatingRowColors();
}

void QtTreePropertyBrowser::setAlternatingRowColors(bool enable)
{
    d_ptr->m_treeWidget->setAlternatingRowColors(enable);
}

/*!
  \property QtTreePropertyBrowser::headerVisible
  \brief whether to show the header.
*/
bool QtTreePropertyBrowser::isHeaderVisible() const
{
    return d_ptr->m_headerVisible;
}

void QtTreePropertyBrowser::setHeaderVisible(bool visible)
{
    if (d_ptr->m_headerVisible == visible)
        return;

    d_ptr->m_headerVisible = visible;
    d_ptr->m_treeWidget->header()->setVisible(visible);
}

/*!
  \enum QtTreePropertyBrowser::ResizeMode

  The resize mode specifies the behavior of the header sections.

  \value Interactive The user can resize the sections.
  The sections can also be resized programmatically using setSplitterPosition().

  \value Fixed The user cannot resize the section.
  The section can only be resized programmatically using setSplitterPosition().

  \value Stretch QHeaderView will automatically resize the section to fill the available space.
  The size cannot be changed by the user or programmatically.

  \value ResizeToContents QHeaderView will automatically resize the section to its optimal
  size based on the contents of the entire column.
  The size cannot be changed by the user or programmatically.

  \sa setResizeMode()
*/

/*!
    \property QtTreePropertyBrowser::resizeMode
    \brief the resize mode of setions in the header.
*/

QtTreePropertyBrowser::ResizeMode QtTreePropertyBrowser::resizeMode() const
{
    return d_ptr->m_resizeMode;
}

void QtTreePropertyBrowser::setResizeMode(QtTreePropertyBrowser::ResizeMode mode)
{
    if (d_ptr->m_resizeMode == mode)
        return;

    d_ptr->m_resizeMode = mode;
    QHeaderView::ResizeMode m = QHeaderView::Stretch;
    switch (mode) {
        case QtTreePropertyBrowser::Interactive:      m = QHeaderView::Interactive;      break;
        case QtTreePropertyBrowser::Fixed:            m = QHeaderView::Fixed;            break;
        case QtTreePropertyBrowser::ResizeToContents: m = QHeaderView::ResizeToContents; break;
        case QtTreePropertyBrowser::Stretch:
        default:                                      m = QHeaderView::Stretch;          break;
    }
    d_ptr->m_treeWidget->header()->setSectionResizeMode(m);
}

/*!
    \property QtTreePropertyBrowser::splitterPosition
    \brief the position of the splitter between the colunms.
*/

int QtTreePropertyBrowser::splitterPosition() const
{
    return d_ptr->m_treeWidget->header()->sectionSize(0);
}

void QtTreePropertyBrowser::setSplitterPosition(int position)
{
    d_ptr->m_treeWidget->header()->resizeSection(0, position);
}

/*!
    Sets the \a item to either collapse or expanded, depending on the value of \a expanded.

    \sa isExpanded(), expanded(), collapsed()
*/

void QtTreePropertyBrowser::setExpanded(QtBrowserItem *item, bool expanded)
{
    QTreeWidgetItem *treeItem = d_ptr->m_indexToItem.value(item);
    if (treeItem)
        treeItem->setExpanded(expanded);
}

/*!
    Returns true if the \a item is expanded; otherwise returns false.

    \sa setExpanded()
*/

bool QtTreePropertyBrowser::isExpanded(QtBrowserItem *item) const
{
    QTreeWidgetItem *treeItem = d_ptr->m_indexToItem.value(item);
    if (treeItem)
        return treeItem->isExpanded();
    return false;
}

/*!
    Returns true if the \a item is visible; otherwise returns false.

    \sa setItemVisible()
    \since 4.5
*/

bool QtTreePropertyBrowser::isItemVisible(QtBrowserItem *item) const
{
    if (const QTreeWidgetItem *treeItem = d_ptr->m_indexToItem.value(item))
        return !treeItem->isHidden();
    return false;
}

/*!
    Sets the \a item to be visible, depending on the value of \a visible.

   \sa isItemVisible()
   \since 4.5
*/

void QtTreePropertyBrowser::setItemVisible(QtBrowserItem *item, bool visible)
{
    if (QTreeWidgetItem *treeItem = d_ptr->m_indexToItem.value(item))
        treeItem->setHidden(!visible);
}

/*!
    Sets the \a item's background color to \a color. Note that while item's background
    is rendered every second row is being drawn with alternate color (which is a bit lighter than items \a color)

    \sa backgroundColor(), calculatedBackgroundColor()
*/

void QtTreePropertyBrowser::setBackgroundColor(QtBrowserItem *item, QColor color)
{
    if (!d_ptr->m_indexToItem.contains(item))
        return;
    if (color.isValid())
        d_ptr->m_indexToBackgroundColor[item] = color;
    else
        d_ptr->m_indexToBackgroundColor.remove(item);
    d_ptr->m_treeWidget->viewport()->update();
}

/*!
    Returns the \a item's color. If there is no color set for item it returns invalid color.

    \sa calculatedBackgroundColor(), setBackgroundColor()
*/

QColor QtTreePropertyBrowser::backgroundColor(QtBrowserItem *item) const
{
    return d_ptr->m_indexToBackgroundColor.value(item);
}

/*!
    Returns the \a item's color. If there is no color set for item it returns parent \a item's
    color (if there is no color set for parent it returns grandparent's color and so on). In case
    the color is not set for \a item and it's top level item it returns invalid color.

    \sa backgroundColor(), setBackgroundColor()
*/

QColor QtTreePropertyBrowser::calculatedBackgroundColor(QtBrowserItem *item) const
{
    return d_ptr->calculatedBackgroundColor(item);
}

/*!
    \property QtTreePropertyBrowser::propertiesWithoutValueMarked
    \brief whether to enable or disable marking properties without value.

    When marking is enabled the item's background is rendered in dark color and item's
    foreground is rendered with light color.

    \sa propertiesWithoutValueMarked()
*/
void QtTreePropertyBrowser::setPropertiesWithoutValueMarked(bool mark)
{
    if (d_ptr->m_markPropertiesWithoutValue == mark)
        return;

    d_ptr->m_markPropertiesWithoutValue = mark;
    for (auto it = d_ptr->m_itemToIndex.cbegin(), end = d_ptr->m_itemToIndex.cend(); it != end; ++it) {
        QtProperty *property = it.value()->property();
        if (!property->hasValue())
            d_ptr->updateItem(it.key());
    }
    d_ptr->m_treeWidget->viewport()->update();
}

bool QtTreePropertyBrowser::propertiesWithoutValueMarked() const
{
    return d_ptr->m_markPropertiesWithoutValue;
}

/*!
    \reimp
*/
void QtTreePropertyBrowser::itemInserted(QtBrowserItem *item, QtBrowserItem *afterItem)
{
    d_ptr->propertyInserted(item, afterItem);
}

/*!
    \reimp
*/
void QtTreePropertyBrowser::itemRemoved(QtBrowserItem *item)
{
    d_ptr->propertyRemoved(item);
}

/*!
    \reimp
*/
void QtTreePropertyBrowser::itemChanged(QtBrowserItem *item)
{
    d_ptr->propertyChanged(item);
}

/*!
    Sets the current item to \a item and opens the relevant editor for it.
*/
void QtTreePropertyBrowser::editItem(QtBrowserItem *item)
{
    d_ptr->editItem(item);
}

QT_END_NAMESPACE

#include "moc_qttreepropertybrowser_p.cpp"
#include "qttreepropertybrowser.moc"