/* osgEarth - Geospatial SDK for OpenSceneGraph
 * Copyright 2018 Pelican Mapping
 * MIT License
 */
#pragma once

#include <osgEarthImGui/ImGuiPanel>
#include <osgEarth/Ephemeris>
#include <osgEarth/Sky>
#include <osgEarth/Shadowing>

namespace osgEarth
{
    using namespace osgEarth::Util;

    class EphemerisGUI : public ImGuiPanel
    {
    private:
        osg::observer_ptr<SkyNode> _skyNode;
        osg::observer_ptr<ShadowCaster> _shadowCaster;
        bool _showDetails;
        float _hour;
        int _day, _month, _year;
        float _exposure;
        float _contrast;
        float _gamma;
        float _ambient;
        bool _first;
        bool _shadows;
        float _haze_cutoff, _haze_strength;
        float _shadow_darkness, _shadow_blur;

    public:
        EphemerisGUI() : BaseGUI("Sky & Lighting"),
            _ambient(0.033f),
            _exposure(3.5f),
            _contrast(1.0f),
            _haze_cutoff(0.0f),
            _haze_strength(16.0f),
            _showDetails(false),
            _shadows(false),
            _shadow_darkness(0.5f),
            _shadow_blur(0.001f),
            _first(true)
        {
            DateTime now;
            _hour = now.hours(), _day = now.day(), _month = now.month(), _year = now.year();
        }

        void load(const Config& conf) override
        {
            conf.get("ShowDetails", _showDetails);
            conf.get("Hour", _hour);
            conf.get("Day", _day);
            conf.get("Month", _month);
            conf.get("Year", _year);
            conf.get("Exposure", _exposure);
            conf.get("Contrast", _contrast);
            conf.get("Ambient", _ambient);
            conf.get("HazeCutoff", _haze_cutoff);
            conf.get("HazeStrength", _haze_strength);
        }
        void save(Config& conf) override
        {
            conf.set("ShowDetails", _showDetails);
            conf.set("Hour", _hour);
            conf.set("Day", _day);
            conf.set("Month", _month);
            conf.set("Year", _year);
            conf.set("Exposure", _exposure);
            conf.set("Contrast", _contrast);
            conf.set("Ambient", _ambient);
            conf.set("HazeCutoff", _haze_cutoff);
            conf.set("HazeStrength", _haze_strength);
        }

        void draw(osg::RenderInfo& ri) override
        {
            if (!isVisible()) return;

            if (!findNodeOrHide(_skyNode, ri))
                return;

            if (_first)
            {
                _first = false;
                findNode(_shadowCaster, ri);
                if (_shadowCaster.valid())
                    _shadows = _shadowCaster->getEnabled();

                _skyNode->setDateTime(DateTime(_year, _month, _day, _hour));

                // so we can visualize tiume-series layers.
                _skyNode->setSimulationTimeTracksDateTime(true);
            }

            ImGui::Begin(name(), visible());
            {
                bool lighting = _skyNode->getLighting();
                ImGui::Checkbox("Lighting", &lighting);
                _skyNode->setLighting(lighting);

                if (_shadowCaster.valid()) {
                    ImGui::SameLine();
                    ImGui::Checkbox("Shadows", &_shadows);
                    _shadowCaster->setEnabled(_shadows);
                }

                ImGui::SameLine();
                if (ImGui::Checkbox("Details", &_showDetails)) dirtySettings();

                ImGui::Separator();

                if (_showDetails)
                    ImGui::Text("Date & Time:");

                if (ImGui::SliderFloat("Hour", &_hour, 0.0f, 24.0f))
                    dirtySettings();

                if (_showDetails)
                {
                    if (ImGui::SliderInt("Day", &_day, 1, 31)) dirtySettings();
                    if (ImGui::SliderInt("Month", &_month, 1, 12)) dirtySettings();
                    if (ImGui::SliderInt("Year", &_year, 1970, 2061)) dirtySettings();
                }

                DateTime mark(_year, _month, _day, _hour);
                _skyNode->setDateTime(mark);

                if (lighting)
                {
                    if (ImGui::SliderFloat("Exposure", &_exposure, 1.0f, 10.0f)) dirtySettings();
                    _skyNode->getOrCreateStateSet()->getOrCreateUniform("oe_sky_exposure", osg::Uniform::FLOAT)->set(_exposure);

                    if (ImGui::SliderFloat("Ambient", &_ambient, 0.0f, 1.0f)) dirtySettings();
                    _skyNode->getSunLight()->setAmbient(osg::Vec4(_ambient, _ambient, _ambient, 1.0f));
                }
                else
                {
                    _shadows = false;
                }

                if (_showDetails)
                {
                    ImGui::Separator();

                    if (_shadows)
                    {
                        if (ImGui::SliderFloat("Shadow darkness", &_shadow_darkness, 0.0f, 1.0f))
                            stateset(ri)->addUniform(new osg::Uniform("oe_shadow_color", _shadow_darkness), 0x7);
                        if (ImGui::SliderFloat("Shadow blur", &_shadow_blur, 0.0f, 0.002f))
                            stateset(ri)->addUniform(new osg::Uniform("oe_shadow_blur", _shadow_blur), 0x07);
                    }

                    ImGui::Separator();

                    if (ImGui::SliderFloat("Haze cutoff", &_haze_cutoff, 0.0f, 0.2f)) dirtySettings();
                    _skyNode->getOrCreateStateSet()->getOrCreateUniform("atmos_haze_cutoff", osg::Uniform::FLOAT)->set(_haze_cutoff);

                    if (ImGui::SliderFloat("Haze strength", &_haze_strength, 0.0f, 24.0f)) dirtySettings();
                    _skyNode->getOrCreateStateSet()->getOrCreateUniform("atmos_haze_strength", osg::Uniform::FLOAT)->set(_haze_strength);

                    bool atmos_visible = _skyNode->getAtmosphereVisible();
                    ImGui::Checkbox("Atmosphere", &atmos_visible);
                    _skyNode->setAtmosphereVisible(atmos_visible);

                    bool sun_visible = _skyNode->getSunVisible();
                    ImGui::Checkbox("Sun", &sun_visible);
                    _skyNode->setSunVisible(sun_visible);

                    ImGui::SameLine();
                    bool moon_visible = _skyNode->getMoonVisible();
                    ImGui::Checkbox("Moon", &moon_visible);
                    _skyNode->setMoonVisible(moon_visible);

                    ImGui::SameLine();
                    bool stars_visible = _skyNode->getStarsVisible();
                    ImGui::Checkbox("Stars", &stars_visible);
                    _skyNode->setStarsVisible(stars_visible);

                    ImGui::Separator();

                    DateTime dt = _skyNode->getDateTime();

                    CelestialBody sun = _skyNode->getEphemeris()->getSunPosition(dt);
                    ImGui::Text("Sun: RA (%.2f) Decl (%.2f)",
                        sun.rightAscension.as(Units::DEGREES),
                        sun.declination.as(Units::DEGREES));

                    CelestialBody moon = _skyNode->getEphemeris()->getMoonPosition(dt);
                    ImGui::Text("Moon: RA (%.2f) Decl (%.2f)",
                        moon.rightAscension.as(Units::DEGREES),
                        moon.declination.as(Units::DEGREES));
                }
            }
            ImGui::End();
        }
    };
}

