/*
 * SPDX-FileCopyrightText: 2005-2009 Thomas Zander <zander@kde.org>
 * SPDX-FileCopyrightText: 2009 Peter Simonsson <peter.simonsson@gmail.com>
 * SPDX-FileCopyrightText: 2010 Cyrille Berger <cberger@cberger.net>
 *
 * SPDX-License-Identifier: LGPL-2.0-or-later
 */
#ifndef _KO_TOOLBOX_LAYOUT_H_
#define _KO_TOOLBOX_LAYOUT_H_

#include <WidgetsDebug.h>
#include <QLayout>
#include <QMap>
#include <QRect>
#include <QAbstractButton>
#include <QDesktopWidget>
#include <QApplication>
#include <QMouseEvent>

class SectionLayout : public QLayout
{
public:
    explicit SectionLayout(QWidget *parent)
        : QLayout(parent), m_orientation(Qt::Vertical)
    {
    }

    ~SectionLayout() override
    {
        qDeleteAll( m_items );
        m_items.clear();
    }

    void addButton(QAbstractButton *button, int priority)
    {
        addChildWidget(button);
        if (m_priorities.values().contains(priority)) {
            qWarning() << "Button" << button << "has a conflicting priority";
        }

        m_priorities.insert(button, priority);
        int index = 1;
        Q_FOREACH (QWidgetItem *item, m_items) {
            if (m_priorities.value(static_cast<QAbstractButton*>(item->widget())) > priority)
                break;
            index++;
        }
        m_items.insert(index-1, new QWidgetItem(button));
    }

    QSize sizeHint() const override
    {
        Q_ASSERT(0);
        return QSize();
    }

    void addItem(QLayoutItem*) override { Q_ASSERT(0); }

    QLayoutItem* itemAt(int i) const override
    {
        if (m_items.count() <= i)
            return 0;
        return m_items.at(i);
    }

    QLayoutItem* takeAt(int i) override { return m_items.takeAt(i); }

    int count() const override { return m_items.count(); }

    void setGeometry (const QRect &rect) override
    {
        int x = 0;
        int y = 0; const QSize &size = buttonSize();
        if (m_orientation == Qt::Vertical) {
            foreach (QWidgetItem* w, m_items) {
                if (w->isEmpty())
                    continue;
                w->widget()->setGeometry(QRect(x, y, size.width(), size.height()));
                x += size.width();
                if (x + size.width() > rect.width()) {
                    x = 0;
                    y += size.height();
                }
            }
        } else {
            foreach (QWidgetItem* w, m_items) {
                if (w->isEmpty())
                    continue;
                w->widget()->setGeometry(QRect(x, y, size.width(), size.height()));
                y += size.height();
                if (y + size.height() > rect.height()) {
                    x += size.width();
                    y = 0;
                }
            }
        }
    }

    void setButtonSize(const QSize size)
    {
        m_buttonSize = size;
    }

    const QSize &buttonSize() const
    {
        return m_buttonSize;
    }

    void setOrientation (Qt::Orientation orientation)
    {
        m_orientation = orientation;
    }

private:
    QSize m_buttonSize;
    QMap<QAbstractButton*, int> m_priorities;
    QList<QWidgetItem*> m_items;
    Qt::Orientation m_orientation;
};

class Section : public QWidget
{
public:
    enum SeparatorFlag {
        SeparatorTop = 0x0001,/* SeparatorBottom = 0x0002, SeparatorRight = 0x0004,*/ SeparatorLeft = 0x0008
    };
    Q_DECLARE_FLAGS(Separators, SeparatorFlag)
    explicit Section(QWidget *parent = 0)
        : QWidget(parent),
        m_layout(new SectionLayout(this))
    {
// Re-enable this when we need to debug the section layout again.
//        setAutoFillBackground(true);
//        static int i = 0;
//        switch(i) {
//        case 0:
//            setStyleSheet("background-color:red");
//            break;
//        case 1:
//            setStyleSheet("background-color:blue");
//            break;
//        case 2:
//            setStyleSheet("background-color:green");
//            break;
//        case 3:
//            setStyleSheet("background-color:yellow");
//            break;
//        case 4:
//            setStyleSheet("background-color:white");
//            break;
//        case 5:
//            setStyleSheet("background-color:gray");
//            break;
//        case 6:
//            setStyleSheet("background-color:lime");
//            break;
//        case 7:
//            setStyleSheet("background-color:silver");
//            break;
//        case 8:
//            setStyleSheet("background-color:purple");
//            break;
//        default:
//            setStyleSheet("background-color:maroon");
//            break;
//        }
//        i++;

    }

    void addButton(QAbstractButton *button, int priority)
    {
        m_layout->addButton(button, priority);
    }

    void setName(const QString &name)
    {
        setObjectName(name);
        m_name = name;
    }

    QString name() const
    {
        return m_name;
    }

    void setButtonSize(QSize size)
    {
        m_layout->setButtonSize(size);
    }

    QSize iconSize() const
    {
        return m_layout->buttonSize();
    }

    int visibleButtonCount() const
    {
        int count = 0;
        for(int i = m_layout->count()-1; i >= 0; --i) {
            if (! static_cast<QWidgetItem*> (m_layout->itemAt(i))->isEmpty())
                ++count;
        }
        return count;
    }

    void setSeparator(Separators separators)
    {
        m_separators = separators;
    }

    Separators separators() const
    {
        return m_separators;
    }

    void setOrientation (Qt::Orientation orientation)
    {
        m_layout->setOrientation(orientation);
    }


protected:
private:
    SectionLayout *m_layout;
    QString m_name;
    Separators m_separators;
};

Q_DECLARE_OPERATORS_FOR_FLAGS(Section::Separators)

class KoToolBoxLayout : public QLayout
{
public:
    explicit KoToolBoxLayout(QWidget *parent)
        : QLayout(parent)
        , m_orientation(Qt::Vertical)
    {
        setSpacing(6);
    }

    ~KoToolBoxLayout() override
    {
        qDeleteAll( m_sections );
        m_sections.clear();
    }

    QSize sizeHint() const override
    {
        // Prefer showing two rows/columns by default
        QSize twoIcons = static_cast<Section*> (m_sections[0]->widget())->iconSize() * 2;
        const int length = doLayout(QRect(QPoint(), twoIcons), false);
        if (m_orientation == Qt::Vertical) {
            return QSize(twoIcons.width(), length);
        } else {
            return QSize(length, twoIcons.height());
        }
    }

    QSize minimumSize() const override
    {
        if (m_sections.isEmpty())
            return QSize();
        QSize oneIcon = static_cast<Section*> (m_sections[0]->widget())->iconSize();
        return oneIcon;
    }

    void addSection(Section *section)
    {
        addChildWidget(section);

        QList<QWidgetItem*>::iterator iterator = m_sections.begin();
        int defaults = 2; // skip the first two as they are the 'main' and 'dynamic' sections.
        while (iterator != m_sections.end()) {
            if (--defaults < 0 && static_cast<Section*> ((*iterator)->widget())->name() > section->name())
                break;
            ++iterator;
        }
        m_sections.insert(iterator, new QWidgetItem(section));
    }

    void addItem(QLayoutItem*) override
    {
        Q_ASSERT(0); // don't let anything else be added. (code depends on this!)
    }

    QLayoutItem* itemAt(int i) const override
    {
        return m_sections.value(i);
    }

    QLayoutItem* takeAt(int i) override { return m_sections.takeAt(i); }

    int count() const override { return m_sections.count(); }

    void setGeometry (const QRect &rect) override
    {
        QLayout::setGeometry(rect);
        doLayout(rect, true);
    }

    bool hasHeightForWidth() const override
    {
        // return true;
        return m_orientation == Qt::Vertical;
    }

    int heightForWidth(int width) const override
    {
        if (m_orientation == Qt::Vertical) {
            const int height = doLayout(QRect(0, 0, width, 0), false);
            return height;
        } else {
    #if 0
            const int iconHeight = static_cast<Section*> (m_sections[0]->widget())->iconSize().height();
            for (int i = 1; i <= 10; i++) {
                const int testWidth = doLayout(QRect(0, 0, 0, iconHeight * i), false);
                if (testWidth <= width) {
                    return iconHeight * i;
                }
            }
            // Return a huge height
            return 65535;
    #endif
            return -1;
        }
    }

    /**
     * For calculating the width from height by KoToolBoxScrollArea.
     * QWidget doesn't actually support trading width for height, so it needs to
     * be handled specifically.
     */
    int widthForHeight(int height) const
    {
        if (m_orientation == Qt::Horizontal) {
            const int width = doLayout(QRect(0, 0, 0, height), false);
            return width;
        } else {
            return -1;
        }
    }

    void setOrientation (Qt::Orientation orientation)
    {
        m_orientation = orientation;
        invalidate();
    }

private:
    int doLayout(const QRect &rect, bool notDryRun) const
    {
        // nothing to do?
        if (m_sections.isEmpty()) {
            return 0;
        }

        // the names of the variables assume a vertical orientation,
        // but all calculations are done based on the real orientation
        const bool isVertical = m_orientation == Qt::Vertical;

        const QSize iconSize = static_cast<Section*> (m_sections.first()->widget())->iconSize();

        const int maxWidth = isVertical ? rect.width() : rect.height();
        // using min 1 as width to e.g. protect against div by 0 below
        const int iconWidth = qMax(1, isVertical ? iconSize.width() : iconSize.height());
        const int iconHeight = qMax(1, isVertical ? iconSize.height() : iconSize.width());

        const int maxColumns = qMax(1, (maxWidth / iconWidth));

        int x = 0;
        int y = 0;
        bool firstSection = true;
        foreach (QWidgetItem *wi, m_sections) {
            Section *section = static_cast<Section*> (wi->widget());
            const int buttonCount = section->visibleButtonCount();
            if (buttonCount == 0) {
                // move out of view, not perfect TODO: better solution
                if (notDryRun) {
                    section->setGeometry(1000, 1000, 0, 0);
                }
                continue;
            }

            // rows needed for the buttons (calculation gets the ceiling value of the plain div)
            const int neededRowCount = ((buttonCount-1) / maxColumns) + 1;

            if (firstSection) {
                firstSection = false;
            } else {
                // start on a new row, set separator
                x = 0;
                y += iconHeight + spacing();
                if (notDryRun){
                    const Section::Separators separator =
                        isVertical ? Section::SeparatorTop : Section::SeparatorLeft;
                    section->setSeparator( separator );
                }
            }

            if (notDryRun) {
                const int usedColumns = qMin(buttonCount, maxColumns);
                if (isVertical) {
                    section->setGeometry(x, y,
                                         usedColumns * iconWidth, neededRowCount * iconHeight);
                } else {
                    section->setGeometry(y, x,
                                         neededRowCount * iconHeight, usedColumns * iconWidth);
                }
            }

            // advance by the icons in the last row
            const int lastRowColumnCount = buttonCount - ((neededRowCount-1) * maxColumns);
            x += (lastRowColumnCount * iconWidth) + spacing();
            // advance by all but the last used row
            y += (neededRowCount - 1) * iconHeight;
        }

        // cache total height (or width), adding the iconHeight for the current row
        return y + iconHeight;
    }

    QList <QWidgetItem*> m_sections;
    Qt::Orientation m_orientation;
};

#endif
