/**
 * @file IcoSphere.cc
 * Copy-pasted from
 *  - https://bitbucket.org/hasyimi/ogre-debug-drawing-utility/src
 *  - http://www.ogre3d.org/tikiwiki/tiki-index.php?page=Debug+Drawing+Utility+Class
 *
 * This source code is released into the Public Domain.
 *
 * Modified by Fabian 'x3n' Landau
 */

#include "IcoSphere.h"

#include <OgreSceneManager.h>
#include <OgreRenderQueue.h>
#include <OgreManualObject.h>
#include <OgreAxisAlignedBox.h>

namespace orxonox
{
    IcoSphere::IcoSphere() :
            index(0)
    {
    }

    IcoSphere::~IcoSphere()
    {
    }

    void IcoSphere::create(int recursionLevel)
    {
        vertices.clear();
        lineIndices.clear();
        triangleIndices.clear();
        faces.clear();
        middlePointIndexCache.clear();
        index = 0;

        float t = (1.0f + Ogre::Math::Sqrt(5.0f)) / 2.0f;

        addVertex(Ogre::Vector3(-1.0f, t, 0.0f));
        addVertex(Ogre::Vector3(1.0f, t, 0.0f));
        addVertex(Ogre::Vector3(-1.0f, -t, 0.0f));
        addVertex(Ogre::Vector3(1.0f, -t, 0.0f));

        addVertex(Ogre::Vector3(0.0f, -1.0f, t));
        addVertex(Ogre::Vector3(0.0f, 1.0f, t));
        addVertex(Ogre::Vector3(0.0f, -1.0f, -t));
        addVertex(Ogre::Vector3(0.0f, 1.0f, -t));

        addVertex(Ogre::Vector3(t, 0.0f, -1.0f));
        addVertex(Ogre::Vector3(t, 0.0f, 1.0f));
        addVertex(Ogre::Vector3(-t, 0.0f, -1.0f));
        addVertex(Ogre::Vector3(-t, 0.0f, 1.0f));

        addFace(0, 11, 5);
        addFace(0, 5, 1);
        addFace(0, 1, 7);
        addFace(0, 7, 10);
        addFace(0, 10, 11);

        addFace(1, 5, 9);
        addFace(5, 11, 4);
        addFace(11, 10, 2);
        addFace(10, 7, 6);
        addFace(7, 1, 8);

        addFace(3, 9, 4);
        addFace(3, 4, 2);
        addFace(3, 2, 6);
        addFace(3, 6, 8);
        addFace(3, 8, 9);

        addFace(4, 9, 5);
        addFace(2, 4, 11);
        addFace(6, 2, 10);
        addFace(8, 6, 7);
        addFace(9, 8, 1);

        addLineIndices(1, 0);
        addLineIndices(1, 5);
        addLineIndices(1, 7);
        addLineIndices(1, 8);
        addLineIndices(1, 9);

        addLineIndices(2, 3);
        addLineIndices(2, 4);
        addLineIndices(2, 6);
        addLineIndices(2, 10);
        addLineIndices(2, 11);

        addLineIndices(0, 5);
        addLineIndices(5, 9);
        addLineIndices(9, 8);
        addLineIndices(8, 7);
        addLineIndices(7, 0);

        addLineIndices(10, 11);
        addLineIndices(11, 4);
        addLineIndices(4, 3);
        addLineIndices(3, 6);
        addLineIndices(6, 10);

        addLineIndices(0, 11);
        addLineIndices(11, 5);
        addLineIndices(5, 4);
        addLineIndices(4, 9);
        addLineIndices(9, 3);
        addLineIndices(3, 8);
        addLineIndices(8, 6);
        addLineIndices(6, 7);
        addLineIndices(7, 10);
        addLineIndices(10, 0);

        for (int i = 0; i < recursionLevel; i++)
        {
            std::list<TriangleIndices> faces2;

            for (const TriangleIndices& f : faces)
            {
                int a = getMiddlePoint(f.v1, f.v2);
                int b = getMiddlePoint(f.v2, f.v3);
                int c = getMiddlePoint(f.v3, f.v1);

                removeLineIndices(f.v1, f.v2);
                removeLineIndices(f.v2, f.v3);
                removeLineIndices(f.v3, f.v1);

                faces2.emplace_back(f.v1, a, c);
                faces2.emplace_back(f.v2, b, a);
                faces2.emplace_back(f.v3, c, b);
                faces2.emplace_back(a, b, c);

                addTriangleLines(f.v1, a, c);
                addTriangleLines(f.v2, b, a);
                addTriangleLines(f.v3, c, b);
            }

            faces = faces2;
        }
    }

    void IcoSphere::addLineIndices(int index0, int index1)
    {
        lineIndices.emplace_back(index0, index1);
    }

    void IcoSphere::removeLineIndices(int index0, int index1)
    {
        std::list<LineIndices>::iterator result = std::find(lineIndices.begin(), lineIndices.end(), LineIndices(index0, index1));

        if (result != lineIndices.end())
            lineIndices.erase(result);
    }

    void IcoSphere::addTriangleLines(int index0, int index1, int index2)
    {
        addLineIndices(index0, index1);
        addLineIndices(index1, index2);
        addLineIndices(index2, index0);
    }

    int IcoSphere::addVertex(const Ogre::Vector3& vertex)
    {
        Ogre::Real length = vertex.length();
        vertices.emplace_back(vertex.x / length, vertex.y / length, vertex.z / length);
        return index++;
    }

    int IcoSphere::getMiddlePoint(int index0, int index1)
    {
        bool isFirstSmaller = index0 < index1;
        int64_t smallerIndex = isFirstSmaller ? index0 : index1;
        int64_t largerIndex = isFirstSmaller ? index1 : index0;
        int64_t key = (smallerIndex << 32) | largerIndex;

        if (middlePointIndexCache.find(key) != middlePointIndexCache.end())
            return middlePointIndexCache[key];

        Ogre::Vector3 point1 = vertices[index0];
        Ogre::Vector3 point2 = vertices[index1];
        Ogre::Vector3 middle = point1.midPoint(point2);

        int index = addVertex(middle);
        middlePointIndexCache[key] = index;
        return index;
    }

    void IcoSphere::addFace(int index0, int index1, int index2)
    {
        faces.emplace_back(index0, index1, index2);
    }

    void IcoSphere::addToLineIndices(int baseIndex, std::list<int>* target) const
    {
        for (const LineIndices& line : lineIndices)
        {
            target->push_back(baseIndex + line.v1);
            target->push_back(baseIndex + line.v2);
        }
    }

    void IcoSphere::addToTriangleIndices(int baseIndex, std::list<int>* target) const
    {
        for (const TriangleIndices& triangle : faces)
        {
            target->push_back(baseIndex + triangle.v1);
            target->push_back(baseIndex + triangle.v2);
            target->push_back(baseIndex + triangle.v3);
        }
    }

    int IcoSphere::addToVertices(std::list<VertexPair>* target, const Ogre::Vector3& position, const Ogre::ColourValue& colour, float scale) const
    {
        Ogre::Matrix4 transform = Ogre::Matrix4::IDENTITY;
        transform.setTrans(position);
        transform.setScale(Ogre::Vector3(scale, scale, scale));

        for (const Ogre::Vector3& vertex : vertices)
            target->emplace_back(transform * vertex, colour);

        return vertices.size();
    }
}