#include "VegetationRenderer.h"

#include "VegetationModelRenderer.h"
#include "RayCastingResult.h"
#include "SpaceGridIterator.h"
#include "SpaceSegment.h"
#include "VegetationInstance.h"
#include "SoftwareRenderer.h"
#include "Scenery.h"
#include "TerrainRenderer.h"
#include "VegetationDefinition.h"
#include "VegetationLayerDefinition.h"
#include "VegetationPresenceDefinition.h"
#include "VegetationInstance.h"
#include "VegetationResult.h"
#include "LightComponent.h"

/**
 * Grid iterator to collect instances of a layer, in small squares.
 */
class VegetationGridIterator: public SpaceGridIterator
{
public:
    VegetationGridIterator(const SpaceSegment &segment, VegetationRenderer *renderer, VegetationLayerDefinition *layer, bool only_hit):
        segment(segment), renderer(renderer), layer(layer), only_hit(only_hit)
    {
    }

    inline const RayCastingResult &getResult() const {return result;}

    virtual bool onCell(int x, int, int z) override
    {
        std::vector<VegetationInstance> instances;

        layer->getPresence()->collectInstances(&instances, *layer->getModel(), x - 0.5, z - 0.5, x + 0.5, z + 0.5);

        for (auto &instance: instances)
        {
            result = renderer->renderInstance(segment, instance, only_hit);
            if (result.hit)
            {
                return false;
            }
        }
        return true;
    }
private:
    const SpaceSegment &segment;
    VegetationRenderer *renderer;
    VegetationLayerDefinition *layer;
    RayCastingResult result;
    bool only_hit;
};

VegetationRenderer::VegetationRenderer(SoftwareRenderer *parent):
    parent(parent)
{
}

void VegetationRenderer::setEnabled(bool enabled)
{
    this->enabled = enabled;
}

RayCastingResult VegetationRenderer::renderInstance(const SpaceSegment &segment, const VegetationInstance &instance, bool only_hit, bool displaced)
{
    if (!displaced)
    {
        // Recursive call on displaced instance
        const Vector3 &base = instance.getBase();
        TerrainRenderer::TerrainResult terrain = parent->getTerrainRenderer()->getResult(base.x, base.z, true, true);
        VegetationInstance displaced_instance = instance.displace(terrain.location, terrain.normal);
        return renderInstance(segment, displaced_instance, only_hit, true);
    }

    RayCastingResult final;
    VegetationModelRenderer model_renderer(parent, &instance.getModel());
    SpaceSegment scaled_segment(segment.getStart().sub(instance.getBase()).scale(1.0 / instance.getSize()),
                                segment.getEnd().sub(instance.getBase()).scale(1.0 / instance.getSize()));
    VegetationResult result = model_renderer.getResult(scaled_segment, only_hit);

    final.hit = result.isHit();

    if (final.hit and not only_hit)
    {
        Vector3 location = result.getLocation().scale(instance.getSize()).add(instance.getBase());
        final.hit_color = parent->applyLightingToSurface(location, result.getNormal(), result.getMaterial());
        final.hit_color = parent->applyMediumTraversal(location, final.hit_color);
        final.hit_location = result.getLocation();
    }

    return final;
}

RayCastingResult VegetationRenderer::getResult(const SpaceSegment &segment, bool only_hit)
{
    if (enabled)
    {
        VegetationDefinition *vegetation = parent->getScenery()->getVegetation();
        int n = vegetation->count();
        // TODO Don't stop at first layer, find the nearest hit
        for (int i = 0; i < n; i++)
        {
            // Find instances potentially crossing the segment
            VegetationGridIterator it(segment, this, vegetation->getVegetationLayer(i), only_hit);
            if (not segment.projectedOnYPlane().iterateOnGrid(it))
            {
                return it.getResult();
            }
        }
        return RayCastingResult();
    }
    else
    {
        return RayCastingResult();
    }
}

bool VegetationRenderer::applyLightFilter(LightComponent &light, const Vector3 &at)
{
    if (enabled)
    {
        // Get segment to iterate
        SpaceSegment segment(at, at.add(light.direction.scale(-1.0 * parent->render_quality)));
        if (getResult(segment, true).hit)
        {
            light.color = COLOR_BLACK;
            return false;
        }
        else
        {
            return true;
        }
    }
    else
    {
        return true;
    }
}