/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2023-05-15
 * Description : geolocation engine based on Marble.
 *               (c) 2007-2022 Marble Team
 *               https://invent.kde.org/education/marble/-/raw/master/data/credits_authors.html
 *
 * SPDX-FileCopyrightText: 2023-2024 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * ============================================================ */

#include "MapScaleFloatItem.h"

// Qt includes

#include <QContextMenuEvent>
#include <QDebug>
#include <QHelpEvent>
#include <QRect>
#include <QPainter>
#include <QPushButton>
#include <QMenu>
#include <QToolTip>

// KDE includes

#include <klocalizedstring.h>

// Local includes

#include "ui_MapScaleConfigWidget.h"
#include "MarbleColors.h"
#include "MarbleGlobal.h"
#include "AbstractProjection.h"
#include "MarbleLocale.h"
#include "MarbleModel.h"
#include "ViewportParams.h"
#include "GeoDataLatLonAltBox.h"

namespace Marble
{

MapScaleFloatItem::MapScaleFloatItem(const MarbleModel* marbleModel)
    : AbstractFloatItem(marbleModel, QPointF(10.5, -10.5), QSizeF(0.0, 40.0)),
      m_configDialog(nullptr),
      m_radius(0),
      m_target(QString()),
      m_leftBarMargin(0),
      m_rightBarMargin(0),
      m_scaleBarWidth(0),
      m_viewportWidth(0),
      m_scaleBarHeight(5),
      m_scaleBarDistance(0.0),
      m_bestDivisor(0),
      m_pixelInterval(0),
      m_valueInterval(0),
      m_scaleInitDone(false),
      m_showRatioScale(false),
      m_contextMenu(nullptr),
      m_minimized(false),
      m_widthScaleFactor(2)
{
    m_minimizeAction = new QAction(i18n("Minimize"), this);
    m_minimizeAction->setCheckable(true);
    m_minimizeAction->setChecked(m_minimized);
    connect(m_minimizeAction, SIGNAL(triggered()), this, SLOT(toggleMinimized()));
}

MapScaleFloatItem::~MapScaleFloatItem()
{
}

QStringList MapScaleFloatItem::backendTypes() const
{
    return QStringList(QStringLiteral("mapscale"));
}

QString MapScaleFloatItem::name() const
{
    return i18n("Scale Bar");
}

QString MapScaleFloatItem::guiString() const
{
    return i18n("&Scale Bar");
}

QString MapScaleFloatItem::nameId() const
{
    return QStringLiteral("scalebar");
}

QString MapScaleFloatItem::version() const
{
    return QStringLiteral("1.1");
}

QString MapScaleFloatItem::description() const
{
    return i18n("A plugin to show a float item that provides a map scale.");
}

QString MapScaleFloatItem::copyrightYears() const
{
    return QStringLiteral("2008, 2010, 2012");
}

QVector<PluginAuthor> MapScaleFloatItem::pluginAuthors() const
{
    return QVector<PluginAuthor>()
           << PluginAuthor(QStringLiteral("Torsten Rahn"), QStringLiteral("tackat@kde.org"), i18n("Original Developer"))
           << PluginAuthor(QStringLiteral("Khanh-Nhan Nguyen"), QStringLiteral("khanh.nhan@wpi.edu"))
           << PluginAuthor(QStringLiteral("Illya Kovalevskyy"), QStringLiteral("illya.kovalevskyy@gmail.com"));
}

QIcon MapScaleFloatItem::icon() const
{
    return QIcon::fromTheme(QStringLiteral("transform-scale-vertical"));
}


void MapScaleFloatItem::initialize()
{
}

bool MapScaleFloatItem::isInitialized() const
{
    return true;
}

void MapScaleFloatItem::setProjection(const ViewportParams* viewport)
{
    int viewportWidth = viewport->width();

    QString target = marbleModel()->planetId();

    if (!(m_radius == viewport->radius()
          && viewportWidth == m_viewportWidth
          && m_target == target
          && m_scaleInitDone))
    {
        int fontHeight     = QFontMetrics(font()).ascent();

        if (m_showRatioScale)
        {
            setContentSize(QSizeF(viewport->width() / m_widthScaleFactor,
                                  fontHeight + 3 + m_scaleBarHeight + fontHeight + 7));
        }

        else
        {
            setContentSize(QSizeF(viewport->width() / m_widthScaleFactor,
                                  fontHeight + 3 + m_scaleBarHeight));
        }

        m_leftBarMargin  = QFontMetrics(font()).boundingRect(QLatin1String("0")).width() / 2;
        m_rightBarMargin = QFontMetrics(font()).boundingRect(QLatin1String("0000")).width() / 2;

        m_scaleBarWidth = contentSize().width() - m_leftBarMargin - m_rightBarMargin;
        m_viewportWidth = viewport->width();
        m_radius = viewport->radius();
        m_scaleInitDone = true;

        m_pixel2Length = marbleModel()->planetRadius() /
                         (qreal)(viewport->radius());

        if (viewport->currentProjection()->surfaceType() == AbstractProjection::Cylindrical)
        {
            qreal centerLatitude = viewport->viewLatLonAltBox().center().latitude();
            // For flat maps we calculate the length of the 90 deg section of the
            // central latitude circle. For flat maps this distance matches
            // the pixel based radius propertyy.
            m_pixel2Length *= M_PI / 2 * cos(centerLatitude);
        }

        m_scaleBarDistance = (qreal)(m_scaleBarWidth) * m_pixel2Length;

        const MarbleLocale::MeasurementSystem measurementSystem =
            MarbleGlobal::getInstance()->locale()->measurementSystem();

        if (measurementSystem != MarbleLocale::MetricSystem)
        {
            m_scaleBarDistance *= KM2MI;
        }

        else if (measurementSystem == MarbleLocale::NauticalSystem)
        {
            m_scaleBarDistance *= KM2NM;
        }

        calcScaleBar();

        update();
    }

    AbstractFloatItem::setProjection(viewport);
}

void MapScaleFloatItem::paintContent(QPainter* painter)
{
    painter->save();

    painter->setRenderHint(QPainter::Antialiasing, true);

    int fontHeight     = QFontMetrics(font()).ascent();

    //calculate scale ratio
    qreal displayMMPerPixel = 1.0 * painter->device()->widthMM() / painter->device()->width();
    qreal ratio = m_pixel2Length / (displayMMPerPixel * MM2M);

    //round ratio to 3 most significant digits, assume that ratio >= 1, otherwise it may display "1 : 0"
    //i made this assumption because as the primary use case we do not need to zoom in that much
    qreal power = 1;
    int iRatio = (int)(ratio + 0.5); //round ratio to the nearest integer

    while (iRatio >= 1000)
    {
        iRatio /= 10;
        power *= 10;
    }

    iRatio *= power;
    m_ratioString.setNum(iRatio);
    m_ratioString = QLatin1String("1 : ") + m_ratioString;

    painter->setPen(QColor(Qt::darkGray));
    painter->setBrush(QColor(Qt::darkGray));
    painter->drawRect(m_leftBarMargin, fontHeight + 3,
                      m_scaleBarWidth,
                      m_scaleBarHeight);

    painter->setPen(QColor(Qt::black));
    painter->setBrush(QColor(Qt::white));
    painter->drawRect(m_leftBarMargin, fontHeight + 3,
                      m_bestDivisor * m_pixelInterval, m_scaleBarHeight);

    painter->setPen(QColor(Oxygen::aluminumGray4));
    painter->drawLine(m_leftBarMargin + 1, fontHeight + 2 + m_scaleBarHeight,
                      m_leftBarMargin + m_bestDivisor * m_pixelInterval - 1, fontHeight + 2 + m_scaleBarHeight);
    painter->setPen(QColor(Qt::black));

    painter->setBrush(QColor(Qt::black));

    QString  intervalStr;
    int      lastStringEnds     = 0;
    int      currentStringBegin = 0;

    for (int j = 0; j <= m_bestDivisor; j += 2)
    {
        if (j < m_bestDivisor)
        {
            painter->drawRect(m_leftBarMargin + j * m_pixelInterval,
                              fontHeight + 3, m_pixelInterval - 1,
                              m_scaleBarHeight);

            painter->setPen(QColor(Oxygen::aluminumGray5));
            painter->drawLine(m_leftBarMargin + j * m_pixelInterval + 1, fontHeight + 4,
                              m_leftBarMargin + (j + 1) * m_pixelInterval - 1, fontHeight + 4);
            painter->setPen(QColor(Qt::black));
        }

        MarbleLocale::MeasurementSystem distanceUnit;
        distanceUnit = MarbleGlobal::getInstance()->locale()->measurementSystem();

        QString unit = i18n("km");

        switch (distanceUnit)
        {
            case MarbleLocale::MetricSystem:
                if (m_bestDivisor * m_valueInterval > 10000)
                {
                    unit = i18n("km");
                    intervalStr.setNum(j * m_valueInterval / 1000);
                }

                else
                {
                    unit = i18n("m");
                    intervalStr.setNum(j * m_valueInterval);
                }

                break;

            case MarbleLocale::ImperialSystem:
                unit = i18n("mi");
                intervalStr.setNum(j * m_valueInterval / 1000);

                if (m_bestDivisor * m_valueInterval > 3800)
                {
                    intervalStr.setNum(j * m_valueInterval / 1000);
                }

                else
                {
                    intervalStr.setNum(qreal(j * m_valueInterval) / 1000.0, 'f', 2);
                }

                break;

            case MarbleLocale::NauticalSystem:
                unit = i18n("nm");
                intervalStr.setNum(j * m_valueInterval / 1000);

                if (m_bestDivisor * m_valueInterval > 3800)
                {
                    intervalStr.setNum(j * m_valueInterval / 1000);
                }

                else
                {
                    intervalStr.setNum(qreal(j * m_valueInterval) / 1000.0, 'f', 2);
                }

                break;
        }

        painter->setFont(font());

        if (j == 0)
        {
            const QString text = QLatin1String("0 ") + unit;
            painter->drawText(0, fontHeight, text);
            lastStringEnds = QFontMetrics(font()).horizontalAdvance(text);
            continue;
        }

        if (j == m_bestDivisor)
        {
            currentStringBegin = (j * m_pixelInterval
                                  - QFontMetrics(font()).boundingRect(intervalStr).width());
        }

        else
        {
            currentStringBegin = (j * m_pixelInterval
                                  - QFontMetrics(font()).horizontalAdvance(intervalStr) / 2);
        }

        if (lastStringEnds < currentStringBegin)
        {
            painter->drawText(currentStringBegin, fontHeight, intervalStr);
            lastStringEnds = currentStringBegin + QFontMetrics(font()).horizontalAdvance(intervalStr);
        }
    }

    int leftRatioIndent = m_leftBarMargin + (m_scaleBarWidth - QFontMetrics(font()).horizontalAdvance(m_ratioString)) / 2;
    painter->drawText(leftRatioIndent, fontHeight + 3 + m_scaleBarHeight + fontHeight + 5, m_ratioString);

    painter->restore();
}

void MapScaleFloatItem::calcScaleBar()
{
    qreal  magnitude = 1;

    // First we calculate the exact length of the whole area that is possibly
    // available to the scalebar in kilometers
    int  magValue = (int)(m_scaleBarDistance);

    // We calculate the two most significant digits of the km-scalebar-length
    // and store them in magValue.
    while (magValue >= 100)
    {
        magValue  /= 10;
        magnitude *= 10;
    }

    m_bestDivisor = 4;
    int  bestMagValue = 1;

    for (int i = 0; i < magValue; i++)
    {
        // We try to find the lowest divisor between 4 and 8 that
        // divides magValue without remainder.
        for (int j = 4; j < 9; j++)
        {
            if ((magValue - i) % j == 0)
            {
                // We store the very first result we find and store
                // m_bestDivisor and bestMagValue as a final result.
                m_bestDivisor = j;
                bestMagValue  = magValue - i;

                // Stop all for loops and end search
                i = magValue;
                j = 9;
            }
        }

        // If magValue doesn't divide through values between 4 and 8
        // (e.g. because it's a prime number) try again with magValue
        // decreased by i.
    }

    m_pixelInterval = (int)(m_scaleBarWidth * (qreal)(bestMagValue)
                            / (qreal)(magValue) / m_bestDivisor);
    m_valueInterval = (int)(bestMagValue * magnitude / m_bestDivisor);
}

QDialog* MapScaleFloatItem::configDialog()
{
    if (!m_configDialog)
    {
        // Initializing configuration dialog
        m_configDialog = new QDialog();
        ui_configWidget = new Ui::MapScaleConfigWidget;
        ui_configWidget->setupUi(m_configDialog);

        readSettings();

        connect(ui_configWidget->m_buttonBox, SIGNAL(accepted()),
                SLOT(writeSettings()));
        connect(ui_configWidget->m_buttonBox, SIGNAL(rejected()),
                SLOT(readSettings()));

        QPushButton* applyButton = ui_configWidget->m_buttonBox->button(QDialogButtonBox::Apply);
        connect(applyButton, SIGNAL(clicked()),
                this,        SLOT(writeSettings()));
    }

    return m_configDialog;
}

void MapScaleFloatItem::contextMenuEvent(QWidget* w, QContextMenuEvent* e)
{
    if (!m_contextMenu)
    {
        m_contextMenu = contextMenu();

        for (QAction* action : m_contextMenu->actions())
        {
            if (action->text() == i18n("&Configure..."))
            {
                m_contextMenu->removeAction(action);
                break;
            }
        }

        QAction* toggleAction = m_contextMenu->addAction(i18n("&Ratio Scale"), this,
                                                         SLOT(toggleRatioScaleVisibility()));
        toggleAction->setCheckable(true);
        toggleAction->setChecked(m_showRatioScale);

        m_contextMenu->addAction(m_minimizeAction);
    }

    Q_ASSERT(m_contextMenu);
    m_contextMenu->exec(w->mapToGlobal(e->pos()));
}

void MapScaleFloatItem::toolTipEvent(QHelpEvent* e)
{
    QToolTip::showText(e->globalPos(), m_ratioString);
}

void MapScaleFloatItem::readSettings()
{
    if (!m_configDialog)
    {
        return;
    }

    if (m_showRatioScale)
    {
        ui_configWidget->m_showRatioScaleCheckBox->setCheckState(Qt::Checked);
    }

    else
    {
        ui_configWidget->m_showRatioScaleCheckBox->setCheckState(Qt::Unchecked);
    }

    ui_configWidget->m_minimizeCheckBox->setChecked(m_minimized);
}

void MapScaleFloatItem::writeSettings()
{
    if (ui_configWidget->m_showRatioScaleCheckBox->checkState() == Qt::Checked)
    {
        m_showRatioScale = true;
    }

    else
    {
        m_showRatioScale = false;
    }

    if (m_minimized != ui_configWidget->m_minimizeCheckBox->isChecked())
    {
        toggleMinimized();
    }

    Q_EMIT settingsChanged(nameId());
}

void MapScaleFloatItem::toggleRatioScaleVisibility()
{
    m_showRatioScale = !m_showRatioScale;
    readSettings();
    Q_EMIT settingsChanged(nameId());
}

void MapScaleFloatItem::toggleMinimized()
{
    m_minimized = !m_minimized;
    ui_configWidget->m_minimizeCheckBox->setChecked(m_minimized);
    m_minimizeAction->setChecked(m_minimized);
    readSettings();
    Q_EMIT settingsChanged(nameId());

    if (m_minimized == true)
    {
        m_widthScaleFactor = 4;
    }

    else
    {
        m_widthScaleFactor = 2;
    }
}

} // namespace Marble

#include "moc_MapScaleFloatItem.cpp"
