// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0

#include "widgetboxcategorylistview.h"

#include <QtDesigner/abstractformeditor.h>
#include <QtDesigner/abstractwidgetdatabase.h>

#include <QtXml/qdom.h>

#include <QtGui/qicon.h>
#include <QtGui/qvalidator.h>
#include <QtWidgets/qlistview.h>
#include <QtWidgets/qlineedit.h>
#include <QtWidgets/qstyleditemdelegate.h>
#include <QtCore/qsortfilterproxymodel.h>

#include <QtCore/qabstractitemmodel.h>
#include <QtCore/qiodevice.h>
#include <QtCore/qlist.h>
#include <QtCore/qtextstream.h>
#include <QtCore/qregularexpression.h>

QT_BEGIN_NAMESPACE

using namespace Qt::StringLiterals;

static constexpr auto widgetElementC = "widget"_L1;
static constexpr auto nameAttributeC = "name"_L1;
static constexpr auto uiOpeningTagC = "<ui>"_L1;
static constexpr auto uiClosingTagC = "</ui>"_L1;

enum { FilterRole = Qt::UserRole + 11 };

static QString domToString(const QDomElement &elt)
{
    QString result;
    QTextStream stream(&result, QIODevice::WriteOnly);
    elt.save(stream, 2);
    stream.flush();
    return result;
}

static QDomDocument stringToDom(const QString &xml)
{
    QDomDocument result;
    result.setContent(xml);
    return result;
}

namespace qdesigner_internal {

// Entry of the model list

struct WidgetBoxCategoryEntry {
    WidgetBoxCategoryEntry() = default;
    explicit WidgetBoxCategoryEntry(const QDesignerWidgetBoxInterface::Widget &widget,
                                    const QString &filter,
                                    const QIcon &icon,
                                    bool editable);

    QDesignerWidgetBoxInterface::Widget widget;
    QString toolTip;
    QString whatsThis;
    QString filter;
    QIcon icon;
    bool editable{false};
};

WidgetBoxCategoryEntry::WidgetBoxCategoryEntry(const QDesignerWidgetBoxInterface::Widget &w,
                                               const QString &filterIn,
                                               const QIcon &i, bool e) :
    widget(w),
    filter(filterIn),
    icon(i),
    editable(e)
{
}

/* WidgetBoxCategoryModel, representing a list of category entries. Uses a
 * QAbstractListModel since the behaviour depends on the view mode of the list
 * view, it does not return text in the case of IconMode. */

class WidgetBoxCategoryModel : public QAbstractListModel {
public:
    explicit WidgetBoxCategoryModel(QDesignerFormEditorInterface *core, QObject *parent = nullptr);

    // QAbstractListModel
    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;
    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
    bool setData(const QModelIndex & index, const QVariant & value, int role = Qt::EditRole) override;
    Qt::ItemFlags flags (const QModelIndex & index ) const override;
    bool removeRows(int row, int count, const QModelIndex &parent = QModelIndex()) override;

    // The model returns no text in icon mode, so, it also needs to know it
    QListView::ViewMode viewMode() const;
    void setViewMode(QListView::ViewMode vm);

    void addWidget(const QDesignerWidgetBoxInterface::Widget &widget, const QIcon &icon, bool editable);

    QDesignerWidgetBoxInterface::Widget widgetAt(const QModelIndex & index) const;
    QDesignerWidgetBoxInterface::Widget widgetAt(int row) const;

    int indexOfWidget(const QString &name);

    QDesignerWidgetBoxInterface::Category category() const;
    bool removeCustomWidgets();

private:
    QDesignerFormEditorInterface *m_core;
    QList<WidgetBoxCategoryEntry> m_items;
    QListView::ViewMode m_viewMode;
};

WidgetBoxCategoryModel::WidgetBoxCategoryModel(QDesignerFormEditorInterface *core, QObject *parent) :
    QAbstractListModel(parent),
    m_core(core),
    m_viewMode(QListView::ListMode)
{
}

QListView::ViewMode WidgetBoxCategoryModel::viewMode() const
{
    return m_viewMode;
}

void WidgetBoxCategoryModel::setViewMode(QListView::ViewMode vm)
{
    if (m_viewMode == vm)
        return;
    const bool empty = m_items.isEmpty();
    if (!empty)
        beginResetModel();
    m_viewMode = vm;
    if (!empty)
        endResetModel();
}

int WidgetBoxCategoryModel::indexOfWidget(const QString &name)
{
    for (qsizetype i = 0, count = m_items.size(); i < count; ++i)
        if (m_items.at(i).widget.name() == name)
            return i;
    return -1;
}

QDesignerWidgetBoxInterface::Category WidgetBoxCategoryModel::category() const
{
    QDesignerWidgetBoxInterface::Category rc;
    for (const auto &c : m_items)
        rc.addWidget(c.widget);
    return rc;
}

bool WidgetBoxCategoryModel::removeCustomWidgets()
{
    // Typically, we are a whole category of custom widgets, so, remove all
    // and do reset.
    bool changed = false;
    for (auto it = m_items.begin(); it != m_items.end(); )
        if (it->widget.type() == QDesignerWidgetBoxInterface::Widget::Custom) {
            if (!changed)
                beginResetModel();
            it = m_items.erase(it);
            changed = true;
        } else {
            ++it;
        }
    if (changed)
        endResetModel();
    return changed;
}

void WidgetBoxCategoryModel::addWidget(const QDesignerWidgetBoxInterface::Widget &widget, const QIcon &icon,bool editable)
{
    static const QRegularExpression classNameRegExp(QStringLiteral("<widget +class *= *\"([^\"]+)\""));
    Q_ASSERT(classNameRegExp.isValid());
    const auto match = classNameRegExp.match(widget.domXml());
    const QString className = match.hasMatch() ? match.captured(1) : QString{};

    // Filter on name + class name if it is different and not a layout.
    QString filter = widget.name();
    if (!className.isEmpty() && !filter.contains("Layout"_L1) && !filter.contains(className))
        filter += className;

    WidgetBoxCategoryEntry item(widget, filter, icon, editable);
    const QDesignerWidgetDataBaseInterface *db = m_core->widgetDataBase();
    int dbIndex = className.isEmpty() ? -1 : db->indexOfClassName(className);
    if (dbIndex == -1)
        dbIndex = db->indexOfClassName(widget.name());
    if (dbIndex != -1) {
        const QDesignerWidgetDataBaseItemInterface *dbItem = db->item(dbIndex);
        const QString toolTip = dbItem->toolTip();
        if (!toolTip.isEmpty())
            item.toolTip = toolTip;
        const QString whatsThis = dbItem->whatsThis();
        if (!whatsThis.isEmpty())
            item.whatsThis = whatsThis;
    }
    // insert
    const int row = m_items.size();
    beginInsertRows(QModelIndex(), row, row);
    m_items.push_back(item);
    endInsertRows();
}

QVariant WidgetBoxCategoryModel::data(const QModelIndex &index, int role) const
{
    const int row = index.row();
    if (row < 0 || row >=  m_items.size())
        return QVariant();

    const WidgetBoxCategoryEntry &item = m_items.at(row);
    switch (role) {
    case Qt::DisplayRole:
        // No text in icon mode
        return QVariant(m_viewMode == QListView::ListMode ? item.widget.name() : QString());
    case Qt::DecorationRole:
        return QVariant(item.icon);
    case Qt::EditRole:
        return QVariant(item.widget.name());
    case Qt::ToolTipRole: {
        if (m_viewMode == QListView::ListMode)
            return QVariant(item.toolTip);
        // Icon mode tooltip should contain the  class name
        QString tt =  item.widget.name();
        if (!item.toolTip.isEmpty())
            tt += u'\n' + item.toolTip;
        return QVariant(tt);

    }
    case Qt::WhatsThisRole:
        return QVariant(item.whatsThis);
    case FilterRole:
        return item.filter;
    }
    return QVariant();
}

bool WidgetBoxCategoryModel::setData(const QModelIndex &index, const QVariant &value, int role)
{
    const int row = index.row();
    if (role != Qt::EditRole || row < 0 || row >=  m_items.size()
        || value.metaType().id() != QMetaType::QString) {
        return false;
    }
    // Set name and adapt Xml
    WidgetBoxCategoryEntry &item = m_items[row];
    const QString newName = value.toString();
    item.widget.setName(newName);

    const QDomDocument doc = stringToDom(WidgetBoxCategoryListView::widgetDomXml(item.widget));
    QDomElement widget_elt = doc.firstChildElement(widgetElementC);
    if (!widget_elt.isNull()) {
        widget_elt.setAttribute(nameAttributeC, newName);
        item.widget.setDomXml(domToString(widget_elt));
    }
    emit dataChanged(index, index);
    return true;
}

Qt::ItemFlags WidgetBoxCategoryModel::flags(const QModelIndex &index) const
{
    Qt::ItemFlags rc = Qt::ItemIsEnabled;
    const int row = index.row();
    if (row >= 0 && row <  m_items.size())
        if (m_items.at(row).editable) {
            rc |= Qt::ItemIsSelectable;
            // Can change name in list mode only
            if (m_viewMode == QListView::ListMode)
                rc |= Qt::ItemIsEditable;
        }
    return rc;
}

int WidgetBoxCategoryModel::rowCount(const QModelIndex & /*parent*/) const
{
    return m_items.size();
}

bool WidgetBoxCategoryModel::removeRows(int row, int count, const QModelIndex & parent)
{
    if (row < 0 || count < 1)
        return false;
    const int size = m_items.size();
    const int last =  row + count - 1;
    if (row >= size || last >= size)
        return false;
    beginRemoveRows(parent, row, last);
    for (int r = last; r >= row; r--)
         m_items.removeAt(r);
    endRemoveRows();
    return true;
}

QDesignerWidgetBoxInterface::Widget WidgetBoxCategoryModel::widgetAt(const QModelIndex & index) const
{
    return widgetAt(index.row());
}

QDesignerWidgetBoxInterface::Widget WidgetBoxCategoryModel::widgetAt(int row) const
{
    if (row < 0 || row >=  m_items.size())
        return QDesignerWidgetBoxInterface::Widget();
    return m_items.at(row).widget;
}

/* WidgetSubBoxItemDelegate, ensures a valid name using a regexp validator */

class WidgetBoxCategoryEntryDelegate : public QStyledItemDelegate
{
public:
    explicit WidgetBoxCategoryEntryDelegate(QWidget *parent = nullptr) : QStyledItemDelegate(parent) {}
    QWidget *createEditor(QWidget *parent,
                          const QStyleOptionViewItem &option,
                          const QModelIndex &index) const override;
};

QWidget *WidgetBoxCategoryEntryDelegate::createEditor(QWidget *parent,
                                                const QStyleOptionViewItem &option,
                                                const QModelIndex &index) const
{
    QWidget *result = QStyledItemDelegate::createEditor(parent, option, index);
    if (QLineEdit *line_edit = qobject_cast<QLineEdit*>(result)) {
        static const QRegularExpression re(u"^[_a-zA-Z][_a-zA-Z0-9]*$"_s);
        Q_ASSERT(re.isValid());
        line_edit->setValidator(new QRegularExpressionValidator(re, line_edit));
    }
    return result;
}

// ----------------------  WidgetBoxCategoryListView

WidgetBoxCategoryListView::WidgetBoxCategoryListView(QDesignerFormEditorInterface *core, QWidget *parent) :
    QListView(parent),
    m_proxyModel(new QSortFilterProxyModel(this)),
    m_model(new WidgetBoxCategoryModel(core, this))
{
    setFocusPolicy(Qt::NoFocus);
    setFrameShape(QFrame::NoFrame);
    setIconSize(QSize(22, 22));
    setSpacing(1);
    setTextElideMode(Qt::ElideMiddle);
    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
    setResizeMode(QListView::Adjust);
    setUniformItemSizes(true);

    setItemDelegate(new WidgetBoxCategoryEntryDelegate(this));

    connect(this, &QListView::pressed, this,
            &WidgetBoxCategoryListView::slotPressed);
    setEditTriggers(QAbstractItemView::AnyKeyPressed);

    m_proxyModel->setSourceModel(m_model);
    m_proxyModel->setFilterRole(FilterRole);
    setModel(m_proxyModel);
    connect(m_model, &QAbstractItemModel::dataChanged,
            this, &WidgetBoxCategoryListView::scratchPadChanged);
}

void WidgetBoxCategoryListView::setViewMode(ViewMode vm)
{
    QListView::setViewMode(vm);
    m_model->setViewMode(vm);
}

void WidgetBoxCategoryListView::setCurrentItem(AccessMode am, int row)
{
    const QModelIndex index = am == FilteredAccess ?
        m_proxyModel->index(row, 0) :
        m_proxyModel->mapFromSource(m_model->index(row, 0));

    if (index.isValid())
        setCurrentIndex(index);
}

void WidgetBoxCategoryListView::slotPressed(const QModelIndex &index)
{
    const QDesignerWidgetBoxInterface::Widget wgt = m_model->widgetAt(m_proxyModel->mapToSource(index));
    if (wgt.isNull())
        return;
    emit widgetBoxPressed(wgt.name(), widgetDomXml(wgt), QCursor::pos());
}

void WidgetBoxCategoryListView::removeCurrentItem()
{
    const QModelIndex index = currentIndex();
    if (!index.isValid() || !m_proxyModel->removeRow(index.row()))
        return;

    // We check the unfiltered item count here, we don't want to get removed if the
    // filtered view is empty
    if (m_model->rowCount()) {
        emit itemRemoved();
    } else {
        emit lastItemRemoved();
    }
}

void WidgetBoxCategoryListView::editCurrentItem()
{
    const QModelIndex index = currentIndex();
    if (index.isValid())
        edit(index);
}

int WidgetBoxCategoryListView::count(AccessMode am) const
{
    return am == FilteredAccess ? m_proxyModel->rowCount() : m_model->rowCount();
}

int WidgetBoxCategoryListView::mapRowToSource(int filterRow) const
{
    const QModelIndex filterIndex = m_proxyModel->index(filterRow, 0);
    return m_proxyModel->mapToSource(filterIndex).row();
}

QDesignerWidgetBoxInterface::Widget WidgetBoxCategoryListView::widgetAt(AccessMode am, const QModelIndex & index) const
{
    const QModelIndex unfilteredIndex = am == FilteredAccess ? m_proxyModel->mapToSource(index) : index;
    return m_model->widgetAt(unfilteredIndex);
}

QDesignerWidgetBoxInterface::Widget WidgetBoxCategoryListView::widgetAt(AccessMode am, int row) const
{
    return m_model->widgetAt(am == UnfilteredAccess ? row : mapRowToSource(row));
}

void WidgetBoxCategoryListView::removeRow(AccessMode am, int row)
{
    m_model->removeRow(am == UnfilteredAccess ? row : mapRowToSource(row));
}

bool WidgetBoxCategoryListView::containsWidget(const QString &name)
{
    return m_model->indexOfWidget(name) != -1;
}

void WidgetBoxCategoryListView::addWidget(const QDesignerWidgetBoxInterface::Widget &widget, const QIcon &icon, bool editable)
{
    m_model->addWidget(widget, icon, editable);
}

QString WidgetBoxCategoryListView::widgetDomXml(const QDesignerWidgetBoxInterface::Widget &widget)
{
    QString domXml = widget.domXml();

    if (domXml.isEmpty())
        domXml = uiOpeningTagC + "<widget class=\""_L1 + widget.name() +"\"/>"_L1 + uiClosingTagC;
    return domXml;
}

void WidgetBoxCategoryListView::filter(const QString &needle, Qt::CaseSensitivity caseSensitivity)
{
    m_proxyModel->setFilterFixedString(needle);
    m_proxyModel->setFilterCaseSensitivity(caseSensitivity);
}

QDesignerWidgetBoxInterface::Category WidgetBoxCategoryListView::category() const
{
    return m_model->category();
}

bool WidgetBoxCategoryListView::removeCustomWidgets()
{
    return m_model->removeCustomWidgets();
}
}  // namespace qdesigner_internal

QT_END_NAMESPACE
