#include "Core/Transform.h"

namespace Transform
{

std::unordered_map<EntityWrapper, glm::vec3> PositionCache;
std::unordered_map<EntityWrapper, glm::quat> OrientationCache;
std::unordered_map<EntityWrapper, glm::vec3> ScaleCache;
std::unordered_map<EntityWrapper, glm::mat4> MatrixCache;

int RecalculatedPositions = 0;
int RecalculatedOrientations = 0;
int RecalculatedScales = 0;

}

//glm::mat4 Transform::AbsoluteTransformation(EntityWrapper entity)
//{
//    glm::mat4 t = glm::mat4(1.f);
//
//    while (entity.Valid()) {
//        t = glm::translate((const glm::vec3&)entity["Transform"]["Position"]) * glm::toMat4(glm::quat((const glm::vec3&)entity["Transform"]["Orientation"])) * glm::scale((const glm::vec3&)entity["Transform"]["Scale"]) * t;
//        entity = entity.Parent();
//    }
//
//    return t;
//}

glm::vec3 Transform::AbsolutePosition(World* world, EntityID entity)
{
    return Transform::AbsolutePosition(EntityWrapper(world, entity));
}

glm::vec3 Transform::AbsolutePosition(EntityWrapper entity)
{
    if (!entity.Valid()) {
        return glm::vec3();
    }

    auto cacheIt = PositionCache.find(entity);
    ComponentWrapper cTransform = entity["Transform"];
    ComponentWrapper::SubscriptProxy cTransformPosition = cTransform["Position"];
    if (cacheIt != PositionCache.end() && !cTransformPosition.Dirty(DirtySetType::Transform)) {
        return cacheIt->second;
    } else {
        EntityWrapper parent = entity.Parent();
        // Calculate position
        glm::vec3 position = AbsolutePosition(parent) + Transform::AbsoluteScale(parent) * (Transform::AbsoluteOrientation(parent) * (const glm::vec3&)cTransformPosition);
        // Cache it
        PositionCache[entity] = position;
        RecalculatedPositions++;
        // Unset dirty flag
        cTransformPosition.SetDirty(DirtySetType::Transform, false);
        // Flag children as dirty
        for (auto& child : entity.ChildrenWithComponent("Transform")) {
            child["Transform"]["Position"].SetDirty(DirtySetType::Transform, true);
        }
        return position;
    }
}

glm::vec3 Transform::AbsoluteOrientationEuler(EntityWrapper entity)
{
    glm::vec3 orientation;

    while (entity.Valid()) {
        ComponentWrapper transform = entity["Transform"];
        orientation += (Field<glm::vec3>)transform["Orientation"];
        entity = entity.Parent();
    }

    return orientation;
}

glm::quat Transform::AbsoluteOrientation(World* world, EntityID entity)
{
    return Transform::AbsoluteOrientation(EntityWrapper(world, entity));
}

glm::quat Transform::AbsoluteOrientation(EntityWrapper entity)
{
    if (!entity.Valid()) {
        return glm::quat();
    }

    auto cacheIt = OrientationCache.find(entity);
    ComponentWrapper cTransform = entity["Transform"];
    ComponentWrapper::SubscriptProxy cTransformOrientation = cTransform["Orientation"];
    if (cacheIt != OrientationCache.end() && !cTransformOrientation.Dirty(DirtySetType::Transform)) {
        return cacheIt->second;
    } else {
        EntityWrapper parent = entity.Parent();
        // Calculate orientation
        glm::quat orientation = AbsoluteOrientation(parent) * glm::quat((const glm::vec3&)cTransformOrientation);
        // Cache it
        OrientationCache[entity] = orientation;
        RecalculatedOrientations++;
        // Unset dirty flag
        cTransformOrientation.SetDirty(DirtySetType::Transform, false);
        // Flag children as dirty
        for (auto& child : entity.ChildrenWithComponent("Transform")) {
            child["Transform"]["Orientation"].SetDirty(DirtySetType::Transform, true);
        }
        return orientation;
    }
}

glm::vec3 Transform::AbsoluteScale(World* world, EntityID entity)
{
    return Transform::AbsoluteScale(EntityWrapper(world, entity));
}

glm::vec3 Transform::AbsoluteScale(EntityWrapper entity)
{
    if (!entity.Valid()) {
        return glm::vec3(1.f);
    }

    auto cacheIt = ScaleCache.find(entity);
    ComponentWrapper cTransform = entity["Transform"];
    ComponentWrapper::SubscriptProxy cTransformScale = cTransform["Scale"];
    if (cacheIt != ScaleCache.end() && !cTransformScale.Dirty(DirtySetType::Transform)) {
        return cacheIt->second;
    } else {
        EntityWrapper parent = entity.Parent();
        // Calculate scale
        glm::vec3 scale = AbsoluteScale(parent) * (const glm::vec3&)cTransformScale;
        // Cache it
        ScaleCache[entity] = scale;
        RecalculatedPositions++;
        // Unset dirty flag
        cTransformScale.SetDirty(DirtySetType::Transform, false);
        // Flag children as dirty
        for (auto& child : entity.ChildrenWithComponent("Transform")) {
            child["Transform"]["Scale"].SetDirty(DirtySetType::Transform, true);
        }
        return scale;
    }
}

glm::mat4 Transform::ModelMatrix(EntityID entityID, World* world)
{
    return ModelMatrix(EntityWrapper(world, entityID));
}

glm::mat4 Transform::ModelMatrix(EntityWrapper entity)
{
    return glm::translate(AbsolutePosition(entity)) * glm::toMat4(AbsoluteOrientation(entity)) * glm::scale(AbsoluteScale(entity));
}

glm::vec3 Transform::TransformPoint(const glm::vec3& point, const glm::mat4& matrix)
{
    return glm::vec3(matrix * glm::vec4(point.x, point.y, point.z, 1));
}