/*
    Scan Tailor - Interactive post-processing tool for scanned pages.
    Copyright (C)  Joseph Artsimovich <joseph.artsimovich@gmail.com>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    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 General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "Thumbnail.h"
#include <QPolygonF>
#include <QPointF>
#include <QRectF>
#include <QSizeF>
#include <QTransform>
#include <QPainter>
#include <QPen>
#include <QBrush>
#include <QColor>

namespace page_split
{

Thumbnail::Thumbnail(
    IntrusivePtr<ThumbnailPixmapCache> const& thumbnail_cache,
    QSizeF const& max_size, ImageId const& image_id,
    ImageTransformation const& xform, PageLayout const& layout,
    bool left_half_removed, bool right_half_removed)
    :   ThumbnailBase(thumbnail_cache, max_size, image_id, xform),
        m_layout(layout),
        m_leftHalfRemoved(left_half_removed),
        m_rightHalfRemoved(right_half_removed)
{
    if (left_half_removed || right_half_removed) {
        m_trashPixmap = QPixmap(":/icons/trashed-small.png");
    }
}

void
Thumbnail::paintOverImage(
    QPainter& painter, QTransform const& image_to_display,
    QTransform const& thumb_to_display)
{
    QRectF const canvas_rect(imageXform().resultingRect());

    painter.setRenderHint(QPainter::Antialiasing, false);
    painter.setWorldTransform(image_to_display);

    painter.setPen(Qt::NoPen);
    switch (m_layout.type()) {
    case PageLayout::SINGLE_PAGE_UNCUT:
        painter.setBrush(QColor(0, 0, 255, 50));
        painter.drawRect(canvas_rect);
        return; // No split line will be drawn.
    case PageLayout::SINGLE_PAGE_CUT:
        painter.setBrush(QColor(0, 0, 255, 50));
        painter.drawPolygon(m_layout.singlePageOutline());
        break;
    case PageLayout::TWO_PAGES:
        QPolygonF const left_poly(m_layout.leftPageOutline());
        QPolygonF const right_poly(m_layout.rightPageOutline());
        painter.setBrush(m_leftHalfRemoved ? QColor(0, 0, 0, 80) : QColor(0, 0, 255, 50));
        painter.drawPolygon(left_poly);
        painter.setBrush(m_rightHalfRemoved ? QColor(0, 0, 0, 80) : QColor(255, 0, 0, 50));
        painter.drawPolygon(right_poly);

        // Draw the trash icon.
        if (m_leftHalfRemoved || m_rightHalfRemoved) {
            painter.setWorldTransform(QTransform());

            int const subpage_idx = m_leftHalfRemoved ? 0 : 1;
            QPointF const center(
                subPageCenter(left_poly, right_poly, image_to_display, subpage_idx)
            );

            QRectF rect(m_trashPixmap.rect());
            rect.moveCenter(center);
            painter.drawPixmap(rect.topLeft(), m_trashPixmap);

            painter.setWorldTransform(image_to_display);
        }
        break;
    }

    painter.setRenderHint(QPainter::Antialiasing, true);

    QPen pen(QColor(0x00, 0x00, 0xff));
    pen.setWidth(1);
    pen.setCosmetic(true);
    painter.setPen(pen);

    switch (m_layout.type()) {
    case PageLayout::SINGLE_PAGE_CUT:
        painter.drawLine(m_layout.inscribedCutterLine(0));
        painter.drawLine(m_layout.inscribedCutterLine(1));
        break;
    case PageLayout::TWO_PAGES:
        painter.drawLine(m_layout.inscribedCutterLine(0));
        break;
    default:;
    }

}

QPointF
Thumbnail::subPageCenter(
    QPolygonF const& left_page, QPolygonF const& right_page,
    QTransform const& image_to_display, int subpage_idx)
{
    QRectF rects[2];
    rects[0] = left_page.boundingRect();
    rects[1] = right_page.boundingRect();

    double const x_mid = 0.5 * (rects[0].right() + rects[1].left());
    rects[0].setRight(x_mid);
    rects[1].setLeft(x_mid);

    return image_to_display.map(rects[subpage_idx].center());
}

} // namespace page_split
