/*
 *   Copyright (C) 2007 Ivan Cukic <ivan.cukic+kde@gmail.com>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library/Lesser General Public License
 *   version 2, or (at your option) any later version, as published by the
 *   Free Software Foundation
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details
 *
 *   You should have received a copy of the GNU Library/Lesser General Public
 *   License along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "kcategorizeditemsviewdelegate_p.h"

#include <cmath>

#include <QtCore/QtCore>

#include <KIconLoader>

#include "kcategorizeditemsview_p.h"

#define FAV_ICON_SIZE 24
#define EMBLEM_ICON_SIZE 16
#define UNIVERSAL_PADDING 6
#define FADE_LENGTH 32
#define MAIN_ICON_SIZE 48
#define DROPDOWN_PADDING 2
#define DROPDOWN_SEPARATOR_HEIGHT 32

KCategorizedItemsViewDelegate::KCategorizedItemsViewDelegate(QObject * parent)
        : QItemDelegate(parent), m_favoriteIcon("bookmarks"),
        m_favoriteAddIcon("list-add"), m_removeIcon("list-remove"),
        m_onFavoriteIconItem(NULL)
{
    m_parent = (KCategorizedItemsView *) parent;
}

void KCategorizedItemsViewDelegate::paint(QPainter *painter,
        const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    KCategorizedItemsViewModels::AbstractItem * item = getItemByProxyIndex(index);
    if (!item) {
        return;
    }

    QStyleOptionViewItemV4 opt(option);
    QStyle *style = opt.widget ? opt.widget->style() : QApplication::style();
    style->drawPrimitive(QStyle::PE_PanelItemViewItem, &opt, painter, opt.widget);

    switch (index.column()) {
    case 0:
        paintColMain(painter, option, item);
        break;
    case 1:
        paintColFav(painter, option, item);
        break;
    case 2:
        paintColRemove(painter, option, item);
        break;
    default:
        kDebug() << "unexpected column";
    }
}

int KCategorizedItemsViewDelegate::calcItemHeight(const QStyleOptionViewItem &option) const
{
    // Painting main column
    QFont titleFont = option.font;
    titleFont.setBold(true);
    titleFont.setPointSize(titleFont.pointSize() + 2);

    int textHeight = QFontInfo(titleFont).pixelSize() + QFontInfo(option.font).pixelSize();
    //kDebug() << textHeight << qMax(textHeight, MAIN_ICON_SIZE) + 2 * UNIVERSAL_PADDING;
    return qMax(textHeight, MAIN_ICON_SIZE) + 2 * UNIVERSAL_PADDING;
}

void KCategorizedItemsViewDelegate::paintColMain(QPainter *painter,
        const QStyleOptionViewItem &option, const KCategorizedItemsViewModels::AbstractItem * item) const
{
    const int left = option.rect.left();
    const int top = option.rect.top();
    const int width = option.rect.width();
    const int height = calcItemHeight(option);

    bool leftToRight = (painter->layoutDirection() == Qt::LeftToRight);
    QIcon::Mode iconMode = QIcon::Normal;

    QColor foregroundColor = (option.state.testFlag(QStyle::State_Selected))?
        option.palette.color(QPalette::HighlightedText):option.palette.color(QPalette::Text);

    // Painting main column
    QFont titleFont = option.font;
    titleFont.setBold(true);
    titleFont.setPointSize(titleFont.pointSize() + 2);

    QPixmap pixmap(width, height);
    pixmap.fill(Qt::transparent);
    QPainter p(&pixmap);
    p.translate(-option.rect.topLeft());

    QLinearGradient gradient;

    QString title = item->name();
    QString description = item->description();

    // Painting

    // Text
    int textInner = 2 * UNIVERSAL_PADDING + MAIN_ICON_SIZE;

    p.setPen(foregroundColor);
    p.setFont(titleFont);
    p.drawText(left + (leftToRight ? textInner : 0),
               top, width - textInner, height / 2,
               Qt::AlignBottom | Qt::AlignLeft, title);
    p.setFont(option.font);
    p.drawText(left + (leftToRight ? textInner : 0),
               top + height / 2,
               width - textInner, height / 2,
               Qt::AlignTop | Qt::AlignLeft, description);

    // Main icon
    item->icon().paint(&p, 
            leftToRight ? left + UNIVERSAL_PADDING : left + width - UNIVERSAL_PADDING - MAIN_ICON_SIZE,
            top + UNIVERSAL_PADDING, 
            MAIN_ICON_SIZE, MAIN_ICON_SIZE, Qt::AlignCenter, iconMode);

    // Counting the number of emblems for this item
    int emblemCount = 0;
    QPair < Filter, QIcon * > emblem;
    foreach (emblem, m_parent->m_emblems) {
        if (item->passesFiltering(emblem.first)) ++emblemCount;
    }

    // Gradient part of the background - fading of the text at the end
    if (leftToRight) {
        gradient = QLinearGradient(left + width - UNIVERSAL_PADDING - FADE_LENGTH, 0, 
                left + width - UNIVERSAL_PADDING, 0);
        gradient.setColorAt(0, Qt::white);
        gradient.setColorAt(1, Qt::transparent);
    } else {
        gradient = QLinearGradient(left + UNIVERSAL_PADDING, 0, 
                left + UNIVERSAL_PADDING + FADE_LENGTH, 0);
        gradient.setColorAt(0, Qt::transparent);
        gradient.setColorAt(1, Qt::white);
    }

    QRect paintRect = option.rect;
    p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
    p.fillRect(paintRect, gradient);

    if (leftToRight) {
        gradient.setStart(left + width
                - emblemCount * (UNIVERSAL_PADDING + EMBLEM_ICON_SIZE) - FADE_LENGTH, 0);
        gradient.setFinalStop(left + width
                - emblemCount * (UNIVERSAL_PADDING + EMBLEM_ICON_SIZE), 0);
    } else {
        gradient.setStart(left + UNIVERSAL_PADDING
                + emblemCount * (UNIVERSAL_PADDING + EMBLEM_ICON_SIZE), 0);
        gradient.setFinalStop(left + UNIVERSAL_PADDING
                + emblemCount * (UNIVERSAL_PADDING + EMBLEM_ICON_SIZE) + FADE_LENGTH, 0);
    }
    paintRect.setHeight(UNIVERSAL_PADDING + MAIN_ICON_SIZE / 2);
    p.fillRect(paintRect, gradient);

    // Emblems icons
    p.setCompositionMode(QPainter::CompositionMode_SourceOver);
    int emblemLeft = leftToRight ? (left + width - EMBLEM_ICON_SIZE) : left; // - FAV_ICON_SIZE - 2 * UNIVERSAL_PADDING
    foreach (emblem, m_parent->m_emblems) {
        if (item->passesFiltering(emblem.first)) {
            emblem.second->paint(&p, 
                    emblemLeft, top + UNIVERSAL_PADDING, 
                    EMBLEM_ICON_SIZE, EMBLEM_ICON_SIZE, Qt::AlignCenter, iconMode);
            if (leftToRight) {
                emblemLeft -= UNIVERSAL_PADDING + EMBLEM_ICON_SIZE;
            } else {
                emblemLeft += UNIVERSAL_PADDING + EMBLEM_ICON_SIZE;
            }
        }
    }
    p.end();

    painter->drawPixmap(option.rect.topLeft(), pixmap);
}

void KCategorizedItemsViewDelegate::paintColFav(QPainter *painter,
        const QStyleOptionViewItem &option, const KCategorizedItemsViewModels::AbstractItem * item) const
{
    int left = option.rect.left();
    int top = option.rect.top();
    int width = option.rect.width();

    // Painting favorite icon column

    if (! (option.state & QStyle::State_MouseOver) && m_onFavoriteIconItem == item)
        m_onFavoriteIconItem = NULL;

    QIcon::Mode iconMode = QIcon::Normal;
    if (!item->isFavorite()) {
        iconMode = QIcon::Disabled;
    } else if (option.state & QStyle::State_MouseOver) {
        iconMode = QIcon::Active;
    } 

    m_favoriteIcon.paint(painter, 
            left + width - FAV_ICON_SIZE - UNIVERSAL_PADDING, top + UNIVERSAL_PADDING, 
            FAV_ICON_SIZE, FAV_ICON_SIZE, Qt::AlignCenter, iconMode);

    const KIcon * icon = (item->isFavorite())? & m_removeIcon : & m_favoriteAddIcon;

    if ((option.state & QStyle::State_MouseOver) && (m_onFavoriteIconItem != item))
        icon->paint(painter, 
                left + width - EMBLEM_ICON_SIZE - UNIVERSAL_PADDING, top + UNIVERSAL_PADDING, 
                EMBLEM_ICON_SIZE, EMBLEM_ICON_SIZE, Qt::AlignCenter, iconMode);
}

void KCategorizedItemsViewDelegate::paintColRemove(QPainter *painter,
        const QStyleOptionViewItem &option, const KCategorizedItemsViewModels::AbstractItem * item) const
{
    // Painting remove icon column
    int running = item->running();
    if (!running) {
        return;
    }

    int left = option.rect.left();
    int top = option.rect.top();
    int width = option.rect.width();

    QIcon::Mode iconMode = QIcon::Normal;
    if (option.state & QStyle::State_MouseOver) {
        iconMode = QIcon::Active;
    } 

    m_removeIcon.paint(painter, 
            left + width - FAV_ICON_SIZE - UNIVERSAL_PADDING, top + UNIVERSAL_PADDING, 
            FAV_ICON_SIZE, FAV_ICON_SIZE, Qt::AlignCenter, iconMode);

    if (running == 1) {
        return;
    }
    //paint number
    QColor foregroundColor = (option.state.testFlag(QStyle::State_Selected))?
        option.palette.color(QPalette::HighlightedText):option.palette.color(QPalette::Text);
    painter->setPen(foregroundColor);
    painter->setFont(option.font);
    painter->drawText(
            left + UNIVERSAL_PADDING, //FIXME might be wrong
            top + UNIVERSAL_PADDING + MAIN_ICON_SIZE / 2,
            width - 2 * UNIVERSAL_PADDING, MAIN_ICON_SIZE / 2,
            Qt::AlignCenter, QString::number(running));
}

bool KCategorizedItemsViewDelegate::editorEvent(QEvent *event,
                               QAbstractItemModel *model,
                               const QStyleOptionViewItem &option,
                               const QModelIndex &index)
{
    if (event->type() == QEvent::MouseButtonPress) {
        KCategorizedItemsViewModels::AbstractItem * item = getItemByProxyIndex(index);
        if (index.column() == 1) {
            m_onFavoriteIconItem = item;
            item->setFavorite(!item->isFavorite());
            return true;
        } else if (index.column() == 2 && item->running()) {
            item->setRunning(0);
            emit destroyApplets(item->name());
            return true;
        }
    }

    return QItemDelegate::editorEvent(event, model, option, index);
}

QSize KCategorizedItemsViewDelegate::sizeHint(const QStyleOptionViewItem &option,
        const QModelIndex &index ) const
{
    int width = (index.column() == 0) ? 0 : FAV_ICON_SIZE;
    return QSize(width, calcItemHeight(option));
}

int KCategorizedItemsViewDelegate::columnWidth (int column, int viewWidth) const {
    if (column != 0) {
        return FAV_ICON_SIZE + 2 * UNIVERSAL_PADDING;
    } else return viewWidth - 2 * columnWidth(1, viewWidth);
}


KCategorizedItemsViewModels::AbstractItem * KCategorizedItemsViewDelegate::getItemByProxyIndex(const QModelIndex & index) const {
    return (AbstractItem *) m_parent->m_modelItems->itemFromIndex(
        m_parent->m_modelFilterItems->mapToSource(index)
    );
}

//     KCategorizedItemsViewFilterDelegate


KCategorizedItemsViewFilterDelegate::KCategorizedItemsViewFilterDelegate(QObject *parent)
    : QItemDelegate(parent) {
    kDebug() << "KCategorizedItemsViewFilterDelegate(QObject *parent)\n";

}

void KCategorizedItemsViewFilterDelegate::paint(QPainter *painter,
        const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if (index.flags() & Qt::ItemIsEnabled) {
        QItemDelegate::paint(painter, option, index);
    } else {
        QStyleOptionViewItem separatorOption(option);
        int height = QItemDelegate::sizeHint(option, index).height() + 2 * DROPDOWN_PADDING;

        separatorOption.state &= ~(QStyle::State_Selected
                | QStyle::State_MouseOver | QStyle::State_HasFocus);
        separatorOption.rect.setTop(separatorOption.rect.top() + separatorOption.rect.height() - height);
        separatorOption.rect.setHeight(height);
        QItemDelegate::paint(painter, separatorOption, index);
        /*painter->drawLine(
                option.rect.left(), 
                option.rect.top() + 1,
                option.rect.left() + option.rect.width(),
                option.rect.top() + 1);*/
    }
}

QSize KCategorizedItemsViewFilterDelegate::sizeHint(const QStyleOptionViewItem &option,
        const QModelIndex &index ) const
{
    QSize size = QItemDelegate::sizeHint(option, index);
    if (index.flags() & Qt::ItemIsEnabled) {
        size.setHeight(size.height() + 2 * DROPDOWN_PADDING);
    } else {
        size.setHeight(DROPDOWN_SEPARATOR_HEIGHT);
    }
    return size;
}

#include "kcategorizeditemsviewdelegate_p.moc"