/* Copyright (C) 2019
 * swift project Community / Contributors
 *
 * This file is part of swift project. It is subject to the license terms in the LICENSE file found in the top-level
 * directory of this distribution. No part of swift project, including this file, may be copied, modified, propagated,
 * or distributed except according to the terms contained in the LICENSE file.
 */

#include "ui_radarcomponent.h"
#include "blackgui/guiapplication.h"
#include "blackgui/infoarea.h"
#include "blackgui/components/radarcomponent.h"
#include "blackcore/context/contextnetwork.h"
#include "blackcore/context/contextownaircraft.h"
#include "blackmisc/simulation/simulatedaircraft.h"

#include <QtMath>
#include <QStringBuilder>

using namespace BlackMisc;
using namespace BlackMisc::Aviation;
using namespace BlackMisc::Simulation;
using namespace BlackMisc::Geo;
using namespace BlackMisc::PhysicalQuantities;
using namespace BlackGui::Views;

namespace BlackGui
{
    namespace Components
    {
        CRadarComponent::CRadarComponent(QWidget *parent) :
            QFrame(parent),
            ui(new Ui::CRadarComponent)
        {
            ui->setupUi(this);

            ui->gv_RadarView->setScene(&m_scene);

            ui->cb_RadarRange->addItem(QString::number(0.5) % u" nm", 0.5);
            for (int r = 1; r <= 9; ++r)
            {
                ui->cb_RadarRange->addItem(QString::number(r) % u" nm", r);
            }
            for (int r = 10; r <= 90; r += 10)
            {
                ui->cb_RadarRange->addItem(QString::number(r) % u" nm", r);
            }

            ui->cb_RadarRange->setCurrentText(QString::number(m_rangeNM) % u" nm");

            connect(ui->gv_RadarView, &CRadarView::radarViewResized, this, &CRadarComponent::fitInView);
            connect(ui->gv_RadarView, &CRadarView::zoomEvent, this, &CRadarComponent::changeRangeInSteps);
            connect(&m_updateTimer,   &QTimer::timeout, this, &CRadarComponent::refreshTargets);
            connect(&m_headingTimer,  &QTimer::timeout, this, &CRadarComponent::rotateView);

            connect(ui->cb_RadarRange,  qOverload<int>(&QComboBox::currentIndexChanged), this, &CRadarComponent::changeRangeFromUserSelection);
            connect(ui->cb_Callsign,    &QCheckBox::toggled, this, &CRadarComponent::refreshTargets);
            connect(ui->cb_Heading,     &QCheckBox::toggled, this, &CRadarComponent::refreshTargets);
            connect(ui->cb_Altitude,    &QCheckBox::toggled, this, &CRadarComponent::refreshTargets);
            connect(ui->cb_GroundSpeed, &QCheckBox::toggled, this, &CRadarComponent::refreshTargets);
            connect(ui->cb_Grid,        &QCheckBox::toggled, this, &CRadarComponent::toggleGrid);

            prepareScene();

            m_updateTimer.start(5000);
            m_headingTimer.start(50);
        }

        CRadarComponent::~CRadarComponent()
        { }

        bool CRadarComponent::setParentDockWidgetInfoArea(CDockWidgetInfoArea *parentDockableWidget)
        {
            CEnableForDockWidgetInfoArea::setParentDockWidgetInfoArea(parentDockableWidget);
            const bool c = connect(this->getParentInfoArea(), &CInfoArea::changedInfoAreaTabBarIndex, this, &CRadarComponent::onInfoAreaTabBarChanged);
            Q_ASSERT_X(c, Q_FUNC_INFO, "failed connect");
            Q_ASSERT_X(parentDockableWidget, Q_FUNC_INFO, "missing parent");
            return c && parentDockableWidget;
        }

        void CRadarComponent::prepareScene()
        {
            m_scene.addItem(&m_center);
            m_scene.addItem(&m_macroGraticule);
            m_scene.addItem(&m_microGraticule);
            m_scene.addItem(&m_radials);
            m_scene.addItem(&m_radarTargets);
            m_radarTargetPen.setCosmetic(true);
            addCenter();
            addGraticules();
            addRadials();
        }

        void CRadarComponent::addCenter()
        {
            QPen pen(Qt::white, 1);
            pen.setCosmetic(true);
            QGraphicsLineItem *lix = new QGraphicsLineItem{QLineF(-5.0, 0.0, 5.0, 0.0), &m_center};
            lix->setFlags(QGraphicsItem::ItemIgnoresTransformations);
            lix->setPen(pen);

            QGraphicsLineItem *liy = new QGraphicsLineItem(QLineF(0.0, -5.0, 0.0, 5.0), &m_center);
            liy->setFlags(QGraphicsItem::ItemIgnoresTransformations);
            liy->setPen(pen);
        }

        void CRadarComponent::addGraticules()
        {
            QPen pen(Qt::white, 1);
            pen.setCosmetic(true);

            // Macro graticule, drawn as full line at every 10 nm
            for (int range = 10; range <= 100; range += 10)
            {
                QGraphicsEllipseItem *circle = new QGraphicsEllipseItem(-range, -range, 2.0 * range, 2.0 * range, &m_macroGraticule);
                circle->setPen(pen);
            }
            pen = QPen(Qt::gray, 1, Qt::DashLine);
            pen.setCosmetic(true);

            // Micro graticule, drawn as dash line at every 2.5 nm
            for (qreal range = 1; range <= 3; ++range)
            {
                QGraphicsEllipseItem *circle = new QGraphicsEllipseItem(-range * 2.5, -range * 2.5, 5.0 * range, 5.0 * range, &m_microGraticule);
                circle->setPen(pen);
            }
        }

        void CRadarComponent::addRadials()
        {
            QPen pen(Qt::gray, 1, Qt::DashDotDotLine);
            pen.setCosmetic(true);

            for (int angle = 0; angle < 360; angle += 30)
            {
                const QLineF line({ 0.0, 0.0 }, polarPoint(1000.0, qDegreesToRadians(static_cast<qreal>(angle))));
                QGraphicsLineItem *li = new QGraphicsLineItem(line, &m_radials);
                li->setFlags(QGraphicsItem::ItemIgnoresTransformations);
                li->setPen(pen);
            }
        }

        void CRadarComponent::refreshTargets()
        {
            if (!sGui || sGui->isShuttingDown()) { return; }

            qDeleteAll(m_radarTargets.childItems());

            if (sGui->getIContextNetwork() && sGui->getIContextNetwork()->isConnected())
            {
                if (isVisibleWidget())
                {
                    const CSimulatedAircraftList aircraft = sGui->getIContextNetwork()->getAircraftInRange();
                    for (const CSimulatedAircraft &sa : aircraft)
                    {
                        const double distanceNM  = sa.getRelativeDistance().value(CLengthUnit::NM());
                        const double bearingRad  = sa.getRelativeBearing().value(CAngleUnit::rad());
                        const int groundSpeedKts = sa.getGroundSpeed().valueInteger(CSpeedUnit::kts());

                        QPointF position(polarPoint(distanceNM, bearingRad));

                        QGraphicsEllipseItem *dot = new QGraphicsEllipseItem(-2.0, -2.0, 4.0, 4.0, &m_radarTargets);
                        dot->setPos(position);
                        dot->setPen(m_radarTargetPen);
                        dot->setBrush(m_radarTargetPen.color());
                        dot->setFlags(QGraphicsItem::ItemIgnoresTransformations);

                        QGraphicsTextItem *tag = new QGraphicsTextItem(&m_radarTargets);
                        QString tagText;
                        if (ui->cb_Callsign->isChecked())
                        {
                            tagText += sa.getCallsignAsString() % u"\n";
                        }
                        if (ui->cb_Altitude->isChecked())
                        {
                            int flightLeveL = sa.getAltitude().valueInteger(CLengthUnit::ft()) / 100;
                            tagText += u"FL" % QStringLiteral("%1").arg(flightLeveL, 3, 10, QChar('0'));
                        }
                        if (ui->cb_GroundSpeed->isChecked())
                        {
                            if (!tagText.isEmpty()) tagText += QStringLiteral(" ");
                            tagText += QString::number(groundSpeedKts) % u" kt";
                        }

                        tag->setPlainText(tagText);
                        tag->setPos(position);
                        tag->setDefaultTextColor(Qt::green);
                        tag->setFlags(QGraphicsItem::ItemIgnoresTransformations);

                        if (ui->cb_Heading->isChecked() && groundSpeedKts > 3.0)
                        {
                            const double headingRad = sa.getHeading().value(CAngleUnit::rad());
                            QPen pen(Qt::green, 1);
                            pen.setCosmetic(true);
                            QGraphicsLineItem *li = new QGraphicsLineItem(QLineF({ 0.0, 0.0 }, polarPoint(5.0, headingRad)), &m_radarTargets);
                            li->setPos(position);
                            li->setPen(pen);
                        }
                    }
                }
            }
        }

        void CRadarComponent::rotateView()
        {
            if (sGui->getIContextOwnAircraft())
            {
                if (isVisibleWidget())
                {
                    int headingDegree = 0;
                    if (! ui->cb_LockNorth->isChecked())
                    {
                        headingDegree = sGui->getIContextOwnAircraft()->getOwnAircraftSituation().getHeading().valueInteger(CAngleUnit::deg());
                    }

                    if (m_rotatenAngle != headingDegree)
                    {
                        // Rotations are summed up, hence rotate back before applying the new rotation.
                        // Doing a global transformation reset will not work as it resets also zooming.
                        ui->gv_RadarView->rotate(m_rotatenAngle);
                        ui->gv_RadarView->rotate(-headingDegree);
                        m_rotatenAngle = headingDegree;
                    }
                }
            }
        }

        void CRadarComponent::toggleGrid(bool checked)
        {
            m_macroGraticule.setVisible(checked);
            m_microGraticule.setVisible(checked);
            m_radials.setVisible(checked);
        }

        void CRadarComponent::fitInView()
        {
            ui->gv_RadarView->fitInView(-m_rangeNM, -m_rangeNM, 2.0 * m_rangeNM, 2.0 * m_rangeNM, Qt::KeepAspectRatio);
        }

        void CRadarComponent::changeRangeInSteps(bool zoomIn)
        {
            qreal direction = zoomIn ? 1.0 : -1.0;
            double factor = 10.0;
            if (m_rangeNM < 10.0 || (qFuzzyCompare(m_rangeNM, 10.0) && zoomIn))
            {
                factor = 1.0;
            }

            if (m_rangeNM < 1.0 || (qFuzzyCompare(m_rangeNM, 1.0) && zoomIn))
            {
                factor = 0.5;
            }

            m_rangeNM = m_rangeNM - direction * factor;
            m_rangeNM = qMin(90.0, qMax(0.5, m_rangeNM));
            ui->cb_RadarRange->setCurrentText(QString::number(m_rangeNM) % u" nm");
            fitInView();
        }

        void CRadarComponent::changeRangeFromUserSelection(int index)
        {
            double range = ui->cb_RadarRange->itemData(index).toDouble();
            if (! qFuzzyCompare(m_rangeNM, range))
            {
                m_rangeNM = range;
                fitInView();
            }
        }

        void CRadarComponent::onInfoAreaTabBarChanged(int index)
        {
            Q_UNUSED(index)

            // ignore in those cases
            if (!this->isVisibleWidget()) return;
            if (this->isParentDockWidgetFloating()) return;
            if (!sGui->getIContextNetwork()->isConnected()) return;

            // here I know I am the selected widget, update, but keep GUI responsive (hence I use a timer)
            QPointer<CRadarComponent> myself(this);
            QTimer::singleShot(1000, this, [ = ]
            {
                if (!myself) { return; }
                myself->refreshTargets();
            });
        }

        QPointF CRadarComponent::polarPoint(double distance, double angleRadians)
        {
            angleRadians = -angleRadians; // conversion assumes angles are counterclockwise

            // standard conversion from https://en.wikipedia.org/wiki/Polar_coordinate_system
            QPointF p(distance * qCos(angleRadians), distance * qSin(angleRadians));

            // conversion yields a coordinate system
            // in which North=(1,0) and East=(-1,0)
            // but we want North=(0,-1) and East=(0,1)
            // (QGraphicsView y axis increases downwards)
            std::swap(p.rx(), p.ry());
            p.setX(-p.x());
            p.setY(-p.y());
            return p;
        }
    } // namespace
} // namespace