// =============================================
//  Aster: nodes.h
//  Copyright (c) 2020-2025 Anish Bhobe
// =============================================

#pragma once

#include "aster/aster.h"

#include <EASTL/vector.h>

struct Nodes
{
    struct Transform
    {
        mat4 m_GlobalTransforms;
        mat4 m_NormalTransforms;

        explicit Transform(mat4 const &transform)
            : m_GlobalTransforms(transform)
            , m_NormalTransforms(transpose(inverse(mat3{transform})))
        {
        }

        Transform &
        operator=(mat4 const &transform)
        {
            m_GlobalTransforms = transform;
            m_NormalTransforms = transpose(inverse(mat3{transform}));
            return *this;
        }
    };

    eastl::vector<mat4> m_Transforms;
    eastl::vector<Transform> m_GlobalTransforms;
    /// Parents are also used for bookkeeping
    eastl::vector<u32> m_Parents_;
    bool m_Dirty = true;

    constexpr static u32 ROOT_BIT = 1u << 31;
    constexpr static u32 DIRTY_BIT = 1u << 30;
    constexpr static u32 PARENT_MASK = ~(ROOT_BIT | DIRTY_BIT);

    u32 Add(mat4 const &transform, i32 parent = -1);
    [[nodiscard]] mat4 const &Get(u32 index) const;
    void Set(u32 index, mat4 const &transform);
    [[nodiscard]] u32 Count() const;

    [[nodiscard]] mat4 const &operator[](u32 index) const;
    [[nodiscard]] mat4 &operator[](u32 index);

    [[nodiscard]] usize GetGlobalTransformByteSize() const;
    [[nodiscard]] Transform const *GetGlobalTransformPtr() const;

    bool Update();
};