/*
    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 "ProcessingIndicationWidget.h"
#include "imageproc/ColorInterpolation.h"
#include <QTimerEvent>
#include <QPaintEvent>
#include <QPainter>
#include <QPalette>
#include <QRect>
#include <QRectF>
#include <math.h>

using namespace imageproc;

static double const distinction_increase = 1.0 / 5.0;
static double const distinction_decrease = -1.0 / 3.0;

ProcessingIndicationWidget::ProcessingIndicationWidget(QWidget* parent)
    :   QWidget(parent),
        m_animation(10),
        m_distinction(1.0),
        m_distinctionDelta(distinction_increase),
        m_timerId(0)
{
    m_headColor = palette().color(QPalette::Window).darker(200);
    m_tailColor = palette().color(QPalette::Window).darker(130);
}

void
ProcessingIndicationWidget::resetAnimation()
{
    m_distinction = 1.0;
    m_distinctionDelta = distinction_increase;
}

void
ProcessingIndicationWidget::processingRestartedEffect()
{
    m_distinction = 1.0;
    m_distinctionDelta = distinction_decrease;
}

void
ProcessingIndicationWidget::paintEvent(QPaintEvent* event)
{
    QRect animation_rect(animationRect());
    if (!event->rect().contains(animation_rect)) {
        update(animation_rect);
        return;
    }

    QColor head_color(colorInterpolation(m_tailColor, m_headColor, m_distinction));

    m_distinction += m_distinctionDelta;
    if (m_distinction > 1.0) {
        m_distinction = 1.0;
    } else if (m_distinction <= 0.0) {
        m_distinction = 0.0;
        m_distinctionDelta = distinction_increase;
    }

    QPainter painter(this);
    m_animation.nextFrame(head_color, m_tailColor, &painter, animation_rect);

    if (m_timerId == 0) {
        m_timerId = startTimer(180);
    }
}

void
ProcessingIndicationWidget::timerEvent(QTimerEvent* event)
{
    killTimer(event->timerId());
    m_timerId = 0;
    update(animationRect());
}

QRect
ProcessingIndicationWidget::animationRect() const
{
    QRect r(0, 0, 80, 80);
    r.moveCenter(rect().center());
    r &= rect();
    return r;
}
