/*
 * This file Copyright (C) 2009-2015 Mnemosyne LLC
 *
 * It may be used under the GNU GPL versions 2 or 3
 * or any future license endorsed by Mnemosyne LLC.
 *
 */

#include <algorithm>

#include <QApplication>
#include <QBrush>
#include <QFont>
#include <QFontMetrics>
#include <QIcon>
#include <QModelIndex>
#include <QPainter>
#include <QPixmap>
#include <QPixmapCache>
#include <QStyleOptionProgressBar>

#include <libtransmission/transmission.h>
#include <libtransmission/utils.h>

#include "Torrent.h"
#include "TorrentDelegateMin.h"
#include "TorrentModel.h"
#include "Utils.h"

enum
{
    GUI_PAD = 6,
    BAR_WIDTH = 50,
    BAR_HEIGHT = 16,
    LINE_SPACING = 4
};

/***
****
****   +---------+-----------------------------------------------+
****   |  Icon   |   Title      shortStatusString [Progressbar]  |
****   +-------- +-----------------------------------------------+
****
***/

namespace
{

class ItemLayout
{
public:
    QFont name_font;
    QFont status_font;

    QRect icon_rect;
    QRect emblem_rect;
    QRect name_rect;
    QRect status_rect;
    QRect bar_rect;

    ItemLayout(QString name_text, QString status_text, QIcon const& emblem_icon, QFont const& base_font,
        Qt::LayoutDirection direction, QPoint const& top_left, int width);

    [[nodiscard]] QSize size() const
    {
        return (icon_rect | name_rect | status_rect | bar_rect).size();
    }

    [[nodiscard]] QString nameText() const
    {
        return elidedText(name_font, name_text_, name_rect.width());
    }

    [[nodiscard]] QString statusText() const
    {
        return status_text_;
    }

private:
    QString name_text_;
    QString status_text_;

    [[nodiscard]] QString elidedText(QFont const& font, QString const& text, int width) const
    {
        return QFontMetrics(font).elidedText(text, Qt::ElideRight, width);
    }
};

ItemLayout::ItemLayout(QString name_text, QString status_text, QIcon const& emblem_icon, QFont const& base_font,
    Qt::LayoutDirection direction, QPoint const& top_left, int width) :
    name_font(base_font),
    status_font(base_font),
    name_text_(std::move(name_text)),
    status_text_(std::move(status_text))
{
    auto const* style = QApplication::style();
    int const icon_size = style->pixelMetric(QStyle::PM_SmallIconSize);

    auto const name_fm = QFontMetrics(name_font);
    auto const name_size = QSize(name_fm.size(0, name_text_));

    status_font.setPointSize(static_cast<int>(status_font.pointSize() * 0.85));
    QFontMetrics const status_fm(status_font);
    QSize const status_size(status_fm.size(0, status_text_));

    QStyleOptionProgressBar bar_style;
    bar_style.rect = QRect(0, 0, BAR_WIDTH, BAR_HEIGHT);
    bar_style.maximum = 100;
    bar_style.progress = 100;
    bar_style.textVisible = true;
    QSize const bar_size(bar_style.rect.width() * 2 - style->subElementRect(QStyle::SE_ProgressBarGroove, &bar_style).width(),
        bar_style.rect.height());

    QRect base_rect(top_left,
        QSize(width, std::max({ icon_size, name_size.height(), status_size.height(), bar_size.height() })));

    icon_rect = QStyle::alignedRect(direction, Qt::AlignLeft | Qt::AlignVCenter, QSize(icon_size, icon_size), base_rect);
    emblem_rect = QStyle::alignedRect(direction, Qt::AlignRight | Qt::AlignBottom, emblem_icon.actualSize(icon_rect.size() / 2,
        QIcon::Normal, QIcon::On), icon_rect);
    bar_rect = QStyle::alignedRect(direction, Qt::AlignRight | Qt::AlignVCenter, bar_size, base_rect);
    Utils::narrowRect(base_rect, icon_rect.width() + GUI_PAD, bar_rect.width() + GUI_PAD, direction);
    status_rect = QStyle::alignedRect(direction, Qt::AlignRight | Qt::AlignVCenter, QSize(status_size.width(),
        base_rect.height()),
        base_rect);
    Utils::narrowRect(base_rect, 0, status_rect.width() + GUI_PAD, direction);
    name_rect = base_rect;
}

} // namespace

QSize TorrentDelegateMin::sizeHint(QStyleOptionViewItem const& option, Torrent const& tor) const
{
    auto const is_magnet = bool(!tor.hasMetadata());
    auto const m = QSize(margin(*QApplication::style()));
    auto const layout = ItemLayout(is_magnet ? progressString(tor) : tor.name(), shortStatusString(tor), QIcon(), option.font,
        option.direction, QPoint(0, 0), option.rect.width() - m.width() * 2);
    return layout.size() + m * 2;
}

void TorrentDelegateMin::drawTorrent(QPainter* painter, QStyleOptionViewItem const& option, Torrent const& tor) const
{
    auto const* style = QApplication::style();

    bool const is_paused(tor.isPaused());
    bool const is_magnet(!tor.hasMetadata());

    bool const is_item_selected((option.state & QStyle::State_Selected) != 0);
    bool const is_item_enabled((option.state & QStyle::State_Enabled) != 0);
    bool const is_item_active((option.state & QStyle::State_Active) != 0);

    painter->save();

    if (is_item_selected)
    {
        QPalette::ColorGroup cg = is_item_enabled ? QPalette::Normal : QPalette::Disabled;

        if (cg == QPalette::Normal && !is_item_active)
        {
            cg = QPalette::Inactive;
        }

        painter->fillRect(option.rect, option.palette.brush(cg, QPalette::Highlight));
    }

    QIcon::Mode im;

    if (is_paused || !is_item_enabled)
    {
        im = QIcon::Disabled;
    }
    else if (is_item_selected)
    {
        im = QIcon::Selected;
    }
    else
    {
        im = QIcon::Normal;
    }

    QIcon::State qs;

    if (is_paused)
    {
        qs = QIcon::Off;
    }
    else
    {
        qs = QIcon::On;
    }

    QPalette::ColorGroup cg = QPalette::Normal;

    if (is_paused || !is_item_enabled)
    {
        cg = QPalette::Disabled;
    }

    if (cg == QPalette::Normal && !is_item_active)
    {
        cg = QPalette::Inactive;
    }

    QPalette::ColorRole cr;

    if (is_item_selected)
    {
        cr = QPalette::HighlightedText;
    }
    else
    {
        cr = QPalette::Text;
    }

    QStyle::State progress_bar_state(option.state);

    if (is_paused)
    {
        progress_bar_state = QStyle::State_None;
    }

    progress_bar_state |= QStyle::State_Small;

    QIcon::Mode const emblem_im = is_item_selected ? QIcon::Selected : QIcon::Normal;
    QIcon const emblem_icon = tor.hasError() ? getWarningEmblem() : QIcon();

    // layout
    QSize const m(margin(*style));
    QRect const content_rect(option.rect.adjusted(m.width(), m.height(), -m.width(), -m.height()));
    ItemLayout const layout(is_magnet ? progressString(tor) : tor.name(), shortStatusString(tor), emblem_icon, option.font,
        option.direction, content_rect.topLeft(), content_rect.width());

    // render
    if (tor.hasError() && !is_item_selected)
    {
        painter->setPen(QColor("red"));
    }
    else
    {
        painter->setPen(option.palette.color(cg, cr));
    }

    tor.getMimeTypeIcon().paint(painter, layout.icon_rect, Qt::AlignCenter, im, qs);

    if (!emblem_icon.isNull())
    {
        emblem_icon.paint(painter, layout.emblem_rect, Qt::AlignCenter, emblem_im, qs);
    }

    painter->setFont(layout.name_font);
    painter->drawText(layout.name_rect, Qt::AlignLeft | Qt::AlignVCenter, layout.nameText());
    painter->setFont(layout.status_font);
    painter->drawText(layout.status_rect, Qt::AlignLeft | Qt::AlignVCenter, layout.statusText());
    progress_bar_style_.rect = layout.bar_rect;

    if (tor.isDownloading())
    {
        progress_bar_style_.palette.setBrush(QPalette::Highlight, BlueBrush);
        progress_bar_style_.palette.setColor(QPalette::Base, BlueBack);
        progress_bar_style_.palette.setColor(QPalette::Window, BlueBack);
    }
    else if (tor.isSeeding())
    {
        progress_bar_style_.palette.setBrush(QPalette::Highlight, GreenBrush);
        progress_bar_style_.palette.setColor(QPalette::Base, GreenBack);
        progress_bar_style_.palette.setColor(QPalette::Window, GreenBack);
    }
    else
    {
        progress_bar_style_.palette.setBrush(QPalette::Highlight, SilverBrush);
        progress_bar_style_.palette.setColor(QPalette::Base, SilverBack);
        progress_bar_style_.palette.setColor(QPalette::Window, SilverBack);
    }

    progress_bar_style_.state = progress_bar_state;
    progress_bar_style_.text = QStringLiteral("%1%").arg(static_cast<int>(tr_truncd(100.0 * tor.percentDone(), 0)));
    progress_bar_style_.textVisible = true;
    progress_bar_style_.textAlignment = Qt::AlignCenter;
    setProgressBarPercentDone(option, tor);
    style->drawControl(QStyle::CE_ProgressBar, &progress_bar_style_, painter);

    painter->restore();
}