#include "water.hpp"

#include <iomanip>

#include <osg/Depth>
#include <osg/Group>
#include <osg/Geode>
#include <osg/Geometry>
#include <osg/Material>
#include <osg/PositionAttitudeTransform>
#include <osg/Depth>
#include <osg/ClipNode>
#include <osg/MatrixTransform>
#include <osg/FrontFace>
#include <osg/Shader>

#include <osgDB/ReadFile> // XXX remove

#include <osgUtil/IncrementalCompileOperation>
#include <osgUtil/CullVisitor>

#include <components/resource/resourcesystem.hpp>
#include <components/resource/texturemanager.hpp>

#include <components/nifosg/controller.hpp>
#include <components/sceneutil/controller.hpp>

#include <components/settings/settings.hpp>

#include <components/esm/loadcell.hpp>

#include "vismask.hpp"
#include "ripplesimulation.hpp"
#include "renderbin.hpp"

namespace
{

    osg::ref_ptr<osg::Geometry> createWaterGeometry(float size, int segments, float textureRepeats)
    {
        osg::ref_ptr<osg::Vec3Array> verts (new osg::Vec3Array);
        osg::ref_ptr<osg::Vec2Array> texcoords (new osg::Vec2Array);

        // some drivers don't like huge triangles, so we do some subdivisons
        // a paged solution would be even better
        const float step = size/segments;
        const float texCoordStep = textureRepeats / segments;
        for (int x=0; x<segments; ++x)
        {
            for (int y=0; y<segments; ++y)
            {
                float x1 = -size/2.f + x*step;
                float y1 = -size/2.f + y*step;
                float x2 = x1 + step;
                float y2 = y1 + step;

                verts->push_back(osg::Vec3f(x1, y2, 0.f));
                verts->push_back(osg::Vec3f(x1, y1, 0.f));
                verts->push_back(osg::Vec3f(x2, y1, 0.f));
                verts->push_back(osg::Vec3f(x2, y2, 0.f));

                float u1 = x*texCoordStep;
                float v1 = y*texCoordStep;
                float u2 = u1 + texCoordStep;
                float v2 = v1 + texCoordStep;

                texcoords->push_back(osg::Vec2f(u1, v2));
                texcoords->push_back(osg::Vec2f(u1, v1));
                texcoords->push_back(osg::Vec2f(u2, v1));
                texcoords->push_back(osg::Vec2f(u2, v2));
            }
        }

        osg::ref_ptr<osg::Geometry> waterGeom (new osg::Geometry);
        waterGeom->setVertexArray(verts);
        waterGeom->setTexCoordArray(0, texcoords);

        waterGeom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS,0,verts->size()));
        return waterGeom;
    }

    void createSimpleWaterStateSet(Resource::ResourceSystem* resourceSystem, osg::ref_ptr<osg::Node> node)
    {
        osg::ref_ptr<osg::StateSet> stateset (new osg::StateSet);

        osg::ref_ptr<osg::Material> material (new osg::Material);
        material->setEmission(osg::Material::FRONT_AND_BACK, osg::Vec4f(1.f, 1.f, 1.f, 1.f));
        material->setDiffuse(osg::Material::FRONT_AND_BACK, osg::Vec4f(0.f, 0.f, 0.f, 0.7f));
        material->setAmbient(osg::Material::FRONT_AND_BACK, osg::Vec4f(0.f, 0.f, 0.f, 1.f));
        material->setColorMode(osg::Material::OFF);
        stateset->setAttributeAndModes(material, osg::StateAttribute::ON);

        stateset->setMode(GL_BLEND, osg::StateAttribute::ON);
        stateset->setMode(GL_CULL_FACE, osg::StateAttribute::OFF);

        osg::ref_ptr<osg::Depth> depth (new osg::Depth);
        depth->setWriteMask(false);
        stateset->setAttributeAndModes(depth, osg::StateAttribute::ON);

        stateset->setRenderBinDetails(MWRender::RenderBin_Water, "RenderBin");

        std::vector<osg::ref_ptr<osg::Texture2D> > textures;
        for (int i=0; i<32; ++i)
        {
            std::ostringstream texname;
            texname << "textures/water/water" << std::setw(2) << std::setfill('0') << i << ".dds";
            textures.push_back(resourceSystem->getTextureManager()->getTexture2D(texname.str(), osg::Texture::REPEAT, osg::Texture::REPEAT));
        }

        osg::ref_ptr<NifOsg::FlipController> controller (new NifOsg::FlipController(0, 2/32.f, textures));
        controller->setSource(boost::shared_ptr<SceneUtil::ControllerSource>(new SceneUtil::FrameTimeSource));
        node->addUpdateCallback(controller);
        node->setStateSet(stateset);
        stateset->setTextureAttributeAndModes(0, textures[0], osg::StateAttribute::ON);
    }

}

namespace MWRender
{

// --------------------------------------------------------------------------------------------------------------------------------

/// @brief Allows to cull and clip meshes that are below a plane. Useful for reflection & refraction camera effects.
/// Also handles flipping of the plane when the eye point goes below it.
/// To use, simply create the scene as subgraph of this node, then do setPlane(const osg::Plane& plane);
class ClipCullNode : public osg::Group
{
    class PlaneCullCallback : public osg::NodeCallback
    {
    public:
        /// @param cullPlane The culling plane (in world space).
        PlaneCullCallback(const osg::Plane* cullPlane)
            : osg::NodeCallback()
            , mCullPlane(cullPlane)
        {
        }

        virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
        {
            osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(nv);

            osg::Polytope::PlaneList origPlaneList = cv->getProjectionCullingStack().back().getFrustum().getPlaneList();

            osg::Plane plane = *mCullPlane;
            plane.transform(*cv->getCurrentRenderStage()->getInitialViewMatrix());

            osg::Vec3d eyePoint = cv->getEyePoint();
            if (mCullPlane->intersect(osg::BoundingSphere(osg::Vec3d(0,0,eyePoint.z()), 0)) > 0)
                plane.flip();

            cv->getProjectionCullingStack().back().getFrustum().add(plane);

            traverse(node, nv);

            // undo
            cv->getProjectionCullingStack().back().getFrustum().set(origPlaneList);
        }

    private:
        const osg::Plane* mCullPlane;
    };

    class FlipCallback : public osg::NodeCallback
    {
    public:
        FlipCallback(const osg::Plane* cullPlane)
            : mCullPlane(cullPlane)
        {
        }

        virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
        {
            osgUtil::CullVisitor* cv = static_cast<osgUtil::CullVisitor*>(nv);
            osg::Vec3d eyePoint = cv->getEyePoint();

            osg::RefMatrix* modelViewMatrix = new osg::RefMatrix(*cv->getModelViewMatrix());

            // flip the below graph if the eye point is above the plane
            if (mCullPlane->intersect(osg::BoundingSphere(osg::Vec3d(0,0,eyePoint.z()), 0)) > 0)
            {
                modelViewMatrix->preMultScale(osg::Vec3(1,1,-1));
            }
            // move the plane back along its normal a little bit to prevent bleeding at the water shore
            const float clipFudge = 5;
            modelViewMatrix->preMultTranslate(mCullPlane->getNormal() * (-clipFudge));

            cv->pushModelViewMatrix(modelViewMatrix, osg::Transform::RELATIVE_RF);
            traverse(node, nv);
            cv->popModelViewMatrix();
        }

    private:
        const osg::Plane* mCullPlane;
    };

public:
    ClipCullNode()
    {
        addCullCallback (new PlaneCullCallback(&mPlane));

        mClipNodeTransform = new osg::PositionAttitudeTransform;
        mClipNodeTransform->addCullCallback(new FlipCallback(&mPlane));
        addChild(mClipNodeTransform);

        mClipNode = new osg::ClipNode;

        mClipNodeTransform->addChild(mClipNode);
    }

    void setPlane (const osg::Plane& plane)
    {
        if (plane == mPlane)
            return;
        mPlane = plane;

        mClipNode->getClipPlaneList().clear();
        mClipNode->addClipPlane(new osg::ClipPlane(0, mPlane));
        mClipNode->setStateSetModes(*getOrCreateStateSet(), osg::StateAttribute::ON);
    }

private:
    osg::ref_ptr<osg::PositionAttitudeTransform> mClipNodeTransform;
    osg::ref_ptr<osg::ClipNode> mClipNode;

    osg::Plane mPlane;
};

// Node callback to entirely skip the traversal.
class NoTraverseCallback : public osg::NodeCallback
{
public:
    virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
    {
        // no traverse()
    }
};

void addDebugOverlay(osg::Texture2D* texture, int pos, osg::Group* parent)
{
    osg::ref_ptr<osg::Camera> debugCamera (new osg::Camera);
    debugCamera->setProjectionMatrix(osg::Matrix::identity());
    debugCamera->setReferenceFrame(osg::Transform::ABSOLUTE_RF);
    debugCamera->setViewMatrix(osg::Matrix::identity());
    debugCamera->setClearMask(0);
    debugCamera->setRenderOrder(osg::Camera::NESTED_RENDER);
    debugCamera->setAllowEventFocus(false);

    const float size = 0.5;
    osg::ref_ptr<osg::Geode> debugGeode (new osg::Geode);
    osg::ref_ptr<osg::Geometry> geom = osg::createTexturedQuadGeometry(osg::Vec3f(-1 + size*pos, -1, 0), osg::Vec3f(size,0,0), osg::Vec3f(0,size,0));
    debugGeode->addDrawable(geom);

    debugCamera->addChild(debugGeode);

    osg::StateSet* debugStateset = geom->getOrCreateStateSet();

    debugStateset->setTextureAttributeAndModes(0, texture, osg::StateAttribute::ON);
    debugStateset->setMode(GL_LIGHTING, osg::StateAttribute::OFF);

    debugStateset->setRenderBinDetails(20, "RenderBin");
    debugStateset->setMode(GL_DEPTH_TEST, osg::StateAttribute::OFF);

    parent->addChild(debugCamera);
}

Water::Water(osg::Group *parent, osg::Group* sceneRoot, Resource::ResourceSystem *resourceSystem, osgUtil::IncrementalCompileOperation *ico,
             const MWWorld::Fallback* fallback, const std::string& resourcePath)
    : mParent(parent)
    , mSceneRoot(sceneRoot)
    , mResourceSystem(resourceSystem)
    , mEnabled(true)
    , mToggled(true)
    , mTop(0)
{
    mSimulation.reset(new RippleSimulation(parent, resourceSystem, fallback));

    osg::ref_ptr<osg::Geometry> waterGeom = createWaterGeometry(CELL_SIZE*150, 40, 900);

    osg::ref_ptr<osg::Geode> geode (new osg::Geode);
    geode->addDrawable(waterGeom);
    geode->setNodeMask(Mask_Water);

    // TODO: node mask to use simple water for local map

    if (ico)
        ico->add(geode);

    //createSimpleWaterStateSet(mResourceSystem, geode);

    mWaterNode = new osg::PositionAttitudeTransform;
    mWaterNode->addChild(geode);

    mSceneRoot->addChild(mWaterNode);

    setHeight(mTop);

    const float waterLevel = -1;

    // refraction
    unsigned int rttSize = Settings::Manager::getInt("rtt size", "Water");
    osg::ref_ptr<osg::Camera> refractionCamera (new osg::Camera);
    refractionCamera->setRenderOrder(osg::Camera::PRE_RENDER);
    refractionCamera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    refractionCamera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
    refractionCamera->setReferenceFrame(osg::Camera::RELATIVE_RF);

    refractionCamera->setCullMask(Mask_Effect|Mask_Scene|Mask_Terrain|Mask_Actor|Mask_ParticleSystem|Mask_Sky|Mask_Player|(1<<16));
    refractionCamera->setNodeMask(Mask_RenderToTexture);
    refractionCamera->setViewport(0, 0, rttSize, rttSize);

    // No need for Update traversal since the mSceneRoot is already updated as part of the main scene graph
    // A double update would mess with the light collection (in addition to being plain redundant)
    refractionCamera->setUpdateCallback(new NoTraverseCallback);

    // No need for fog here, we are already applying fog on the water surface itself as well as underwater fog
    refractionCamera->getOrCreateStateSet()->setMode(GL_FOG, osg::StateAttribute::OFF|osg::StateAttribute::OVERRIDE);

    osg::ref_ptr<ClipCullNode> clipNode (new ClipCullNode);
    clipNode->setPlane(osg::Plane(osg::Vec3d(0,0,-1), osg::Vec3d(0,0, waterLevel)));

    refractionCamera->addChild(clipNode);
    clipNode->addChild(mSceneRoot);

    // TODO: add ingame setting for texture quality

    osg::ref_ptr<osg::Texture2D> refractionTexture = new osg::Texture2D;
    refractionTexture->setTextureSize(rttSize, rttSize);
    refractionTexture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
    refractionTexture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
    refractionTexture->setInternalFormat(GL_RGB);
    refractionTexture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
    refractionTexture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);

    refractionCamera->attach(osg::Camera::COLOR_BUFFER, refractionTexture);

    osg::ref_ptr<osg::Texture2D> refractionDepthTexture = new osg::Texture2D;
    refractionDepthTexture->setSourceFormat(GL_DEPTH_COMPONENT);
    refractionDepthTexture->setInternalFormat(GL_DEPTH_COMPONENT24_ARB);
    refractionDepthTexture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
    refractionDepthTexture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
    refractionDepthTexture->setSourceType(GL_UNSIGNED_INT);
    refractionDepthTexture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
    refractionDepthTexture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);

    refractionCamera->attach(osg::Camera::DEPTH_BUFFER, refractionDepthTexture);

    mParent->addChild(refractionCamera);

    // reflection
    osg::ref_ptr<osg::Camera> reflectionCamera (new osg::Camera);
    reflectionCamera->setRenderOrder(osg::Camera::PRE_RENDER);
    reflectionCamera->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    reflectionCamera->setRenderTargetImplementation(osg::Camera::FRAME_BUFFER_OBJECT);
    reflectionCamera->setReferenceFrame(osg::Camera::RELATIVE_RF);

    reflectionCamera->setCullMask(Mask_Effect|Mask_Scene|Mask_Terrain|Mask_Actor|Mask_ParticleSystem|Mask_Sky|Mask_Player|(1<<16));
    reflectionCamera->setNodeMask(Mask_RenderToTexture);

    reflectionCamera->setViewport(0, 0, rttSize, rttSize);

    // No need for Update traversal since the mSceneRoot is already updated as part of the main scene graph
    // A double update would mess with the light collection (in addition to being plain redundant)
    reflectionCamera->setUpdateCallback(new NoTraverseCallback);

    osg::ref_ptr<osg::Texture2D> reflectionTexture = new osg::Texture2D;
    reflectionTexture->setInternalFormat(GL_RGB);
    reflectionTexture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
    reflectionTexture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
    reflectionTexture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
    reflectionTexture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);

    reflectionCamera->attach(osg::Camera::COLOR_BUFFER, reflectionTexture);

    reflectionCamera->setViewMatrix(osg::Matrix::translate(0,0,-waterLevel) * osg::Matrix::scale(1,1,-1) * osg::Matrix::translate(0,0,waterLevel));

    osg::ref_ptr<osg::MatrixTransform> reflectNode (new osg::MatrixTransform);

    // XXX: should really flip the FrontFace on each renderable instead of forcing clockwise.
    osg::ref_ptr<osg::FrontFace> frontFace (new osg::FrontFace);
    frontFace->setMode(osg::FrontFace::CLOCKWISE);
    reflectNode->getOrCreateStateSet()->setAttributeAndModes(frontFace, osg::StateAttribute::ON);

    osg::ref_ptr<ClipCullNode> clipNode2 (new ClipCullNode);
    clipNode2->setPlane(osg::Plane(osg::Vec3d(0,0,1), osg::Vec3d(0,0,waterLevel)));

    reflectNode->addChild(clipNode2);
    clipNode2->addChild(mSceneRoot);

    reflectionCamera->addChild(reflectNode);

    // TODO: add to waterNode so cameras don't get updated when water is hidden?

    mParent->addChild(reflectionCamera);

    // debug overlay
    addDebugOverlay(refractionTexture, 0, mParent);
    addDebugOverlay(refractionDepthTexture, 1, mParent);
    addDebugOverlay(reflectionTexture, 2, mParent);

    // shader
    // FIXME: windows utf8 path handling?

    osg::ref_ptr<osg::Shader> vertexShader (osg::Shader::readShaderFile(osg::Shader::VERTEX, resourcePath + "/shaders/water_vertex.glsl"));

    osg::ref_ptr<osg::Shader> fragmentShader (osg::Shader::readShaderFile(osg::Shader::FRAGMENT, resourcePath + "/shaders/water_fragment.glsl"));

    osg::ref_ptr<osg::Program> program (new osg::Program);
    program->addShader(vertexShader);
    program->addShader(fragmentShader);

    osg::ref_ptr<osg::Texture2D> normalMap (new osg::Texture2D(osgDB::readImageFile(resourcePath + "/shaders/water_nm.png")));
    normalMap->setWrap(osg::Texture::WRAP_S, osg::Texture::REPEAT);
    normalMap->setWrap(osg::Texture::WRAP_T, osg::Texture::REPEAT);
    normalMap->setMaxAnisotropy(16);
    normalMap->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR_MIPMAP_LINEAR);
    normalMap->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
    normalMap->getImage()->flipVertical();

    osg::ref_ptr<osg::StateSet> shaderStateset = new osg::StateSet;
    shaderStateset->setAttributeAndModes(program, osg::StateAttribute::ON);
    shaderStateset->addUniform(new osg::Uniform("reflectionMap", 0));
    shaderStateset->addUniform(new osg::Uniform("refractionMap", 1));
    shaderStateset->addUniform(new osg::Uniform("refractionDepthMap", 2));
    shaderStateset->addUniform(new osg::Uniform("normalMap", 3));

    shaderStateset->setTextureAttributeAndModes(0, reflectionTexture, osg::StateAttribute::ON);
    shaderStateset->setTextureAttributeAndModes(1, refractionTexture, osg::StateAttribute::ON);
    shaderStateset->setTextureAttributeAndModes(2, refractionDepthTexture, osg::StateAttribute::ON);
    shaderStateset->setTextureAttributeAndModes(3, normalMap, osg::StateAttribute::ON);
    shaderStateset->setMode(GL_BLEND, osg::StateAttribute::ON); // TODO: set Off when refraction is on
    shaderStateset->setMode(GL_CULL_FACE, osg::StateAttribute::OFF);

    osg::ref_ptr<osg::Depth> depth (new osg::Depth);
    depth->setWriteMask(false);
    shaderStateset->setAttributeAndModes(depth, osg::StateAttribute::ON);

    // TODO: render after transparent bin when refraction is on
    shaderStateset->setRenderBinDetails(MWRender::RenderBin_Water, "RenderBin");

    geode->setStateSet(shaderStateset);
}

Water::~Water()
{
    mParent->removeChild(mWaterNode);
}

void Water::setEnabled(bool enabled)
{
    mEnabled = enabled;
    updateVisible();
}

void Water::changeCell(const MWWorld::CellStore* store)
{
    if (store->getCell()->isExterior())
        mWaterNode->setPosition(getSceneNodeCoordinates(store->getCell()->mData.mX, store->getCell()->mData.mY));
    else
        mWaterNode->setPosition(osg::Vec3f(0,0,mTop));

    // create a new StateSet to prevent threading issues
    osg::ref_ptr<osg::StateSet> nodeStateSet (new osg::StateSet);
    nodeStateSet->addUniform(new osg::Uniform("nodePosition", osg::Vec3f(mWaterNode->getPosition())));
    mWaterNode->setStateSet(nodeStateSet);
}

void Water::setHeight(const float height)
{
    mTop = height;

    mSimulation->setWaterHeight(height);

    osg::Vec3f pos = mWaterNode->getPosition();
    pos.z() = height;
    mWaterNode->setPosition(pos);
}

void Water::update(float dt)
{
    mSimulation->update(dt);
}

void Water::updateVisible()
{
    mWaterNode->setNodeMask(mEnabled && mToggled ? ~0 : 0);
}

bool Water::toggle()
{
    mToggled = !mToggled;
    updateVisible();
    return mToggled;
}

bool Water::isUnderwater(const osg::Vec3f &pos) const
{
    return pos.z() < mTop && mToggled && mEnabled;
}

osg::Vec3f Water::getSceneNodeCoordinates(int gridX, int gridY)
{
    return osg::Vec3f(static_cast<float>(gridX * CELL_SIZE + (CELL_SIZE / 2)), static_cast<float>(gridY * CELL_SIZE + (CELL_SIZE / 2)), mTop);
}

void Water::addEmitter (const MWWorld::Ptr& ptr, float scale, float force)
{
    mSimulation->addEmitter (ptr, scale, force);
}

void Water::removeEmitter (const MWWorld::Ptr& ptr)
{
    mSimulation->removeEmitter (ptr);
}

void Water::updateEmitterPtr (const MWWorld::Ptr& old, const MWWorld::Ptr& ptr)
{
    mSimulation->updateEmitterPtr(old, ptr);
}

void Water::removeCell(const MWWorld::CellStore *store)
{
    mSimulation->removeCell(store);
}

void Water::clearRipples()
{
    mSimulation->clear();
}

}