/*****************************************************************************************
*                                                                                       *
* OpenSpace                                                                             *
*                                                                                       *
* Copyright (c) 2014-2016                                                               *
*                                                                                       *
* Permission is hereby granted, free of charge, to any person obtaining a copy of this  *
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* permit persons to whom the Software is furnished to do so, subject to the following   *
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* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software.                                              *
*                                                                                       *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,   *
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A         *
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****************************************************************************************/

#include <modules/globebrowsing/chunk/chunkedlodglobe.h>

#include <modules/globebrowsing/meshes/skirtedgrid.h>
#include <modules/globebrowsing/chunk/culling.h>
#include <modules/globebrowsing/chunk/chunklevelevaluator.h>

#include <modules/debugging/rendering/debugrenderer.h>


// open space includes
#include <openspace/engine/openspaceengine.h>
#include <openspace/rendering/renderengine.h>
#include <openspace/util/spicemanager.h>
#include <openspace/scene/scenegraphnode.h>

// ghoul includes
#include <ghoul/misc/assert.h>

#define _USE_MATH_DEFINES
#include <math.h>

namespace {
    const std::string _loggerCat = "ChunkLodGlobe";
}

namespace openspace {

    const GeodeticPatch ChunkedLodGlobe::LEFT_HEMISPHERE = GeodeticPatch(0, -M_PI/2, M_PI/2, M_PI/2);
    const GeodeticPatch ChunkedLodGlobe::RIGHT_HEMISPHERE = GeodeticPatch(0, M_PI/2, M_PI/2, M_PI/2);

    const ChunkIndex ChunkedLodGlobe::LEFT_HEMISPHERE_INDEX = ChunkIndex(0, 0, 1);
    const ChunkIndex ChunkedLodGlobe::RIGHT_HEMISPHERE_INDEX = ChunkIndex(1, 0, 1);


    ChunkedLodGlobe::ChunkedLodGlobe(
        const Ellipsoid& ellipsoid,
        size_t segmentsPerPatch,
        std::shared_ptr<TileProviderManager> tileProviderManager)
        : _ellipsoid(ellipsoid)
        , _leftRoot(new ChunkNode(Chunk(this, LEFT_HEMISPHERE_INDEX)))
        , _rightRoot(new ChunkNode(Chunk(this, RIGHT_HEMISPHERE_INDEX)))
        , minSplitDepth(2)
        , maxSplitDepth(22)
        , _savedCamera(nullptr)
        , _tileProviderManager(tileProviderManager)
    {

        auto geometry = std::make_shared<SkirtedGrid>(
            (unsigned int) segmentsPerPatch,
            (unsigned int) segmentsPerPatch,
            TriangleSoup::Positions::No,
            TriangleSoup::TextureCoordinates::Yes,
            TriangleSoup::Normals::No);

        _chunkCullers.push_back(new HorizonCuller());
        _chunkCullers.push_back(new FrustumCuller(AABB3(vec3(-1, -1, 0), vec3(1, 1, 1e35))));

        
        
        _chunkEvaluatorByAvailableTiles = std::make_unique<EvaluateChunkLevelByAvailableTileData>();
        _chunkEvaluatorByProjectedArea = std::make_unique<EvaluateChunkLevelByProjectedArea>();
        _chunkEvaluatorByDistance = std::make_unique<EvaluateChunkLevelByDistance>();

        _patchRenderer = std::make_unique<ChunkRenderer>(geometry, tileProviderManager);
    }

    ChunkedLodGlobe::~ChunkedLodGlobe() {

    }

    bool ChunkedLodGlobe::initialize() {
        return isReady();
    }

    bool ChunkedLodGlobe::deinitialize() {
        return true;
    }

    bool ChunkedLodGlobe::isReady() const {
        bool ready = true;
        return ready;
    }

    std::shared_ptr<TileProviderManager> ChunkedLodGlobe::getTileProviderManager() const {
        return _tileProviderManager;
    }


    ChunkRenderer& ChunkedLodGlobe::getPatchRenderer() const{
        return *_patchRenderer;
    }

    bool ChunkedLodGlobe::testIfCullable(const Chunk& chunk, const RenderData& renderData) const {
        if (doHorizonCulling && _chunkCullers[0]->isCullable(chunk, renderData)) {
            return true;
        }
        if (doFrustumCulling && _chunkCullers[1]->isCullable(chunk, renderData)) {
            return true;
        }
        return false;
    }

    int ChunkedLodGlobe::getDesiredLevel(const Chunk& chunk, const RenderData& renderData) const {
        int desiredLevel = 0;
        if (levelByProjArea) {
            desiredLevel = _chunkEvaluatorByProjectedArea->getDesiredLevel(chunk, renderData);
        }
        else {
            desiredLevel = _chunkEvaluatorByDistance->getDesiredLevel(chunk, renderData);
        }

        if (limitLevelByAvailableHeightData) {
            int desiredLevelByAvailableData = _chunkEvaluatorByAvailableTiles->getDesiredLevel(chunk, renderData);
            if (desiredLevelByAvailableData != ChunkLevelEvaluator::UNKNOWN_DESIRED_LEVEL) {
                desiredLevel = min(desiredLevel, desiredLevelByAvailableData);
            }
        }

        desiredLevel = glm::clamp(desiredLevel, minSplitDepth, maxSplitDepth);
        return desiredLevel;
    }

    
    void ChunkedLodGlobe::render(const RenderData& data){
        minDistToCamera = INFINITY;
        ChunkNode::renderedChunks = 0;

        _leftRoot->updateChunkTree(data);
        _rightRoot->updateChunkTree(data);

        renderChunkTree(_leftRoot.get(), data);
        renderChunkTree(_rightRoot.get(), data);


        // Calculate the MVP matrix
        dmat4 modelTransform = translate(dmat4(1), data.position.dvec3());
        dmat4 viewTransform = dmat4(data.camera.combinedViewMatrix());
        dmat4 mvp = dmat4(data.camera.projectionMatrix())
            * viewTransform * modelTransform;

        if (showChunkBounds) {
            std::function<void(const ChunkNode&)> chunkDebugRenderer = [&data, &mvp](const ChunkNode& chunkNode) {
                const Chunk& chunk = chunkNode.getChunk();
                if (chunkNode.isLeaf() && chunk.isVisible()) {
                    const std::vector<glm::dvec4> modelSpaceCorners = chunk.getBoundingPolyhedronCorners();
                    std::vector<glm::vec4> clippingSpaceCorners(8);
                    for (size_t i = 0; i < 8; i++) {
                        clippingSpaceCorners[i] = mvp * modelSpaceCorners[i];
                    }

                    unsigned int colorBits = 1 + chunk.index().level % 6;
                    vec4 color = vec4(colorBits & 1, colorBits & 2, colorBits & 4, 0.3);
                    DebugRenderer::ref()->renderBoxFaces(clippingSpaceCorners, color);

                    glLineWidth(4.0f);
                    DebugRenderer::ref()->renderBoxEdges(clippingSpaceCorners, color);

                    glPointSize(20.0f);
                    DebugRenderer::ref()->renderVertices(clippingSpaceCorners, GL_POINTS, color);
                }
            };

            _leftRoot->depthFirst(chunkDebugRenderer);
            _rightRoot->depthFirst(chunkDebugRenderer);
        }
       

        //LDEBUG("min distnace to camera: " << minDistToCamera);

        Vec3 cameraPos = data.camera.position().dvec3();
        //LDEBUG("cam pos  x: " << cameraPos.x << "  y: " << cameraPos.y << "  z: " << cameraPos.z);

        //LDEBUG("ChunkNode count: " << ChunkNode::chunkNodeCount);
        //LDEBUG("RenderedPatches count: " << ChunkNode::renderedChunks);
        //LDEBUG(ChunkNode::renderedChunks << " / " << ChunkNode::chunkNodeCount << " chunks rendered");
    }

    void ChunkedLodGlobe::renderChunkTree(ChunkNode* node, const RenderData& data) const {
        if (renderSmallChunksFirst) {
            node->renderReversedBreadthFirst(data);
        }
        else {
            node->renderDepthFirst(data);
        }
        
    }

    void ChunkedLodGlobe::update(const UpdateData& data) {
        _patchRenderer->update();
        
    }

    void ChunkedLodGlobe::setStateMatrix(const glm::dmat3& stateMatrix)
    {
        _stateMatrix = stateMatrix;
    }

    const glm::dmat3& ChunkedLodGlobe::stateMatrix()
    {
        return _stateMatrix;
    }

    const Ellipsoid& ChunkedLodGlobe::ellipsoid() const
    {
        return _ellipsoid;
    }

}  // namespace openspace