/* Copyright 2013-2018 MultiMC Contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "InstanceDelegate.h"
#include <QPainter>
#include <QTextOption>
#include <QTextLayout>
#include <QApplication>
#include <QtMath>
#include <QDebug>

#include "GroupView.h"
#include "BaseInstance.h"
#include "InstanceList.h"
#include <xdgicon.h>
#include <QPlainTextEdit>

// Origin: Qt
static void viewItemTextLayout(QTextLayout &textLayout, int lineWidth, qreal &height,
                               qreal &widthUsed)
{
    height = 0;
    widthUsed = 0;
    textLayout.beginLayout();
    QString str = textLayout.text();
    while (true)
    {
        QTextLine line = textLayout.createLine();
        if (!line.isValid())
            break;
        if (line.textLength() == 0)
            break;
        line.setLineWidth(lineWidth);
        line.setPosition(QPointF(0, height));
        height += line.height();
        widthUsed = qMax(widthUsed, line.naturalTextWidth());
    }
    textLayout.endLayout();
}

ListViewDelegate::ListViewDelegate(QObject *parent) : QStyledItemDelegate(parent)
{
}

void drawSelectionRect(QPainter *painter, const QStyleOptionViewItem &option,
                       const QRect &rect)
{
    if ((option.state & QStyle::State_Selected))
        painter->fillRect(rect, option.palette.brush(QPalette::Highlight));
    else
    {
        QColor backgroundColor = option.palette.color(QPalette::Background);
        backgroundColor.setAlpha(160);
        painter->fillRect(rect, QBrush(backgroundColor));
    }
}

void drawFocusRect(QPainter *painter, const QStyleOptionViewItem &option, const QRect &rect)
{
    if (!(option.state & QStyle::State_HasFocus))
        return;
    QStyleOptionFocusRect opt;
    opt.direction = option.direction;
    opt.fontMetrics = option.fontMetrics;
    opt.palette = option.palette;
    opt.rect = rect;
    // opt.state           = option.state | QStyle::State_KeyboardFocusChange |
    // QStyle::State_Item;
    auto col = option.state & QStyle::State_Selected ? QPalette::Highlight : QPalette::Base;
    opt.backgroundColor = option.palette.color(col);
    // Apparently some widget styles expect this hint to not be set
    painter->setRenderHint(QPainter::Antialiasing, false);

    QStyle *style = option.widget ? option.widget->style() : QApplication::style();

    style->drawPrimitive(QStyle::PE_FrameFocusRect, &opt, painter, option.widget);

    painter->setRenderHint(QPainter::Antialiasing);
}

// TODO this can be made a lot prettier
void drawProgressOverlay(QPainter *painter, const QStyleOptionViewItem &option,
                         const int value, const int maximum)
{
    if (maximum == 0 || value == maximum)
    {
        return;
    }

    painter->save();

    qreal percent = (qreal)value / (qreal)maximum;
    QColor color = option.palette.color(QPalette::Dark);
    color.setAlphaF(0.70f);
    painter->setBrush(color);
    painter->setPen(QPen(QBrush(), 0));
    painter->drawPie(option.rect, 90 * 16, -percent * 360 * 16);

    painter->restore();
}

void drawBadges(QPainter *painter, const QStyleOptionViewItem &option, BaseInstance *instance, QIcon::Mode mode, QIcon::State state)
{
    QList<QString> pixmaps;
    if (instance->isRunning())
    {
        pixmaps.append("status-running");
    }
    else if (instance->hasCrashed() || instance->hasVersionBroken())
    {
        pixmaps.append("status-bad");
    }
    if (instance->hasUpdateAvailable())
    {
        pixmaps.append("checkupdate");
    }

    static const int itemSide = 24;
    static const int spacing = 1;
    const int itemsPerRow = qMax(1, qFloor(double(option.rect.width() + spacing) / double(itemSide + spacing)));
    const int rows = qCeil((double)pixmaps.size() / (double)itemsPerRow);
    QListIterator<QString> it(pixmaps);
    painter->translate(option.rect.topLeft());
    for (int y = 0; y < rows; ++y)
    {
        for (int x = 0; x < itemsPerRow; ++x)
        {
            if (!it.hasNext())
            {
                return;
            }
            // FIXME: inject this.
            auto icon = XdgIcon::fromTheme(it.next());
            // opt.icon.paint(painter, iconbox, Qt::AlignCenter, mode, state);
            const QPixmap pixmap;
            // itemSide
            QRect badgeRect(
                option.rect.width() - x * itemSide + qMax(x - 1, 0) * spacing - itemSide,
                y * itemSide + qMax(y - 1, 0) * spacing,
                itemSide,
                itemSide
            );
            icon.paint(painter, badgeRect, Qt::AlignCenter, mode, state);
        }
    }
    painter->translate(-option.rect.topLeft());
}

static QSize viewItemTextSize(const QStyleOptionViewItem *option)
{
    QStyle *style = option->widget ? option->widget->style() : QApplication::style();
    QTextOption textOption;
    textOption.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);
    QTextLayout textLayout;
    textLayout.setTextOption(textOption);
    textLayout.setFont(option->font);
    textLayout.setText(option->text);
    const int textMargin = style->pixelMetric(QStyle::PM_FocusFrameHMargin, option, option->widget) + 1;
    QRect bounds(0, 0, 100 - 2 * textMargin, 600);
    qreal height = 0, widthUsed = 0;
    viewItemTextLayout(textLayout, bounds.width(), height, widthUsed);
    const QSize size(qCeil(widthUsed), qCeil(height));
    return QSize(size.width() + 2 * textMargin, size.height());
}

void ListViewDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
                             const QModelIndex &index) const
{
    QStyleOptionViewItem opt = option;
    initStyleOption(&opt, index);
    painter->save();
    painter->setClipRect(opt.rect);

    opt.features |= QStyleOptionViewItem::WrapText;
    opt.text = index.data().toString();
    opt.textElideMode = Qt::ElideRight;
    opt.displayAlignment = Qt::AlignTop | Qt::AlignHCenter;

    QStyle *style = opt.widget ? opt.widget->style() : QApplication::style();

    // const int iconSize =  style->pixelMetric(QStyle::PM_IconViewIconSize);
    const int iconSize = 48;
    QRect iconbox = opt.rect;
    const int textMargin = style->pixelMetric(QStyle::PM_FocusFrameHMargin, 0, opt.widget) + 1;
    QRect textRect = opt.rect;
    QRect textHighlightRect = textRect;
    // clip the decoration on top, remove width padding
    textRect.adjust(textMargin, iconSize + textMargin + 5, -textMargin, 0);

    textHighlightRect.adjust(0, iconSize + 5, 0, 0);

    // draw background
    {
        // FIXME: unused
        // QSize textSize = viewItemTextSize ( &opt );
        QPalette::ColorGroup cg;
        QStyleOptionViewItem opt2(opt);

        if ((opt.widget && opt.widget->isEnabled()) || (opt.state & QStyle::State_Enabled))
        {
            if (!(opt.state & QStyle::State_Active))
                cg = QPalette::Inactive;
            else
                cg = QPalette::Normal;
        }
        else
        {
            cg = QPalette::Disabled;
        }
        opt2.palette.setCurrentColorGroup(cg);

        // fill in background, if any

        if (opt.backgroundBrush.style() != Qt::NoBrush)
        {
            QPointF oldBO = painter->brushOrigin();
            painter->setBrushOrigin(opt.rect.topLeft());
            painter->fillRect(opt.rect, opt.backgroundBrush);
            painter->setBrushOrigin(oldBO);
        }

        drawSelectionRect(painter, opt2, textHighlightRect);

        /*
        if (opt.showDecorationSelected)
        {
            drawSelectionRect(painter, opt2, opt.rect);
            drawFocusRect(painter, opt2, opt.rect);
            // painter->fillRect ( opt.rect, opt.palette.brush ( cg, QPalette::Highlight ) );
        }
        else
        {

            // if ( opt.state & QStyle::State_Selected )
            {
                // QRect textRect = subElementRect ( QStyle::SE_ItemViewItemText,  opt,
                // opt.widget );
                // painter->fillRect ( textHighlightRect, opt.palette.brush ( cg,
                // QPalette::Highlight ) );
                drawSelectionRect(painter, opt2, textHighlightRect);
                drawFocusRect(painter, opt2, textHighlightRect);
            }
        }
        */
    }

    // icon mode and state, also used for badges
    QIcon::Mode mode = QIcon::Normal;
    if (!(opt.state & QStyle::State_Enabled))
        mode = QIcon::Disabled;
    else if (opt.state & QStyle::State_Selected)
        mode = QIcon::Selected;
    QIcon::State state = opt.state & QStyle::State_Open ? QIcon::On : QIcon::Off;

    // draw the icon
    {
        iconbox.setHeight(iconSize);
        opt.icon.paint(painter, iconbox, Qt::AlignCenter, mode, state);
    }
    // set the text colors
    QPalette::ColorGroup cg =
        opt.state & QStyle::State_Enabled ? QPalette::Normal : QPalette::Disabled;
    if (cg == QPalette::Normal && !(opt.state & QStyle::State_Active))
        cg = QPalette::Inactive;
    if (opt.state & QStyle::State_Selected)
    {
        painter->setPen(opt.palette.color(cg, QPalette::HighlightedText));
    }
    else
    {
        painter->setPen(opt.palette.color(cg, QPalette::Text));
    }

    // draw the text
    QTextOption textOption;
    textOption.setWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere);
    textOption.setTextDirection(opt.direction);
    textOption.setAlignment(QStyle::visualAlignment(opt.direction, opt.displayAlignment));
    QTextLayout textLayout;
    textLayout.setTextOption(textOption);
    textLayout.setFont(opt.font);
    textLayout.setText(opt.text);

    qreal width, height;
    viewItemTextLayout(textLayout, textRect.width(), height, width);

    const int lineCount = textLayout.lineCount();

    const QRect layoutRect = QStyle::alignedRect(
        opt.direction, opt.displayAlignment, QSize(textRect.width(), int(height)), textRect);
    const QPointF position = layoutRect.topLeft();
    for (int i = 0; i < lineCount; ++i)
    {
        const QTextLine line = textLayout.lineAt(i);
        line.draw(painter, position);
    }

    // FIXME: this really has no business of being here. Make generic.
    auto instance = (BaseInstance*)index.data(InstanceList::InstancePointerRole)
            .value<void *>();
    if (instance)
    {
        drawBadges(painter, opt, instance, mode, state);
    }

    drawProgressOverlay(painter, opt, index.data(GroupViewRoles::ProgressValueRole).toInt(),
                        index.data(GroupViewRoles::ProgressMaximumRole).toInt());

    painter->restore();
}

QSize ListViewDelegate::sizeHint(const QStyleOptionViewItem &option,
                                 const QModelIndex &index) const
{
    QStyleOptionViewItem opt = option;
    initStyleOption(&opt, index);
    opt.features |= QStyleOptionViewItem::WrapText;
    opt.text = index.data().toString();
    opt.textElideMode = Qt::ElideRight;
    opt.displayAlignment = Qt::AlignTop | Qt::AlignHCenter;

    QStyle *style = opt.widget ? opt.widget->style() : QApplication::style();
    const int textMargin = style->pixelMetric(QStyle::PM_FocusFrameHMargin, &option, opt.widget) + 1;
    int height = 48 + textMargin * 2 + 5; // TODO: turn constants into variables
    QSize szz = viewItemTextSize(&opt);
    height += szz.height();
    // FIXME: maybe the icon items could scale and keep proportions?
    QSize sz(100, height);
    return sz;
}

void ListViewDelegate::updateEditorGeometry(QWidget* editor, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
    const int iconSize = 48;
    QRect textRect = option.rect;
    textRect.adjust(0, iconSize + 5, 0, 0);
    editor->setGeometry(textRect);
}

QWidget * ListViewDelegate::createEditor(QWidget* parent, const QStyleOptionViewItem& option, const QModelIndex& index) const
{
    auto *le = new QLineEdit(parent);
    le->setFrame(false);
    return le;
}