//
// Created by sfd on 25-11-21.
//

#ifndef DEMOLAYER_H
#define DEMOLAYER_H

#include "Prism.h"
#include "Prism/Renderer/Camera.h"
#include "Prism/Renderer/FrameBuffer.h"
#include "Prism/Renderer/Material.h"
#include "Prism/Renderer/Mesh.h"

class DemoLayer : public Prism::Layer
{
public:
    DemoLayer();
    virtual ~DemoLayer();

    virtual void OnAttach() override;
    virtual void OnDetach() override;
    virtual void OnUpdate(Prism::TimeStep deltaTime) override;
    virtual void OnImGuiRender() override;
    virtual void OnEvent(Prism::Event& e) override;

private:
    float m_ClearColor[4];

    Prism::Ref<Prism::Shader> m_QuadShader;
    Prism::Ref<Prism::Shader> m_HDRShader;
    Prism::Ref<Prism::Shader> m_GridShader;
    Prism::Ref<Prism::Mesh> m_Mesh;
    Prism::Ref<Prism::Mesh> m_SphereMesh, m_PlaneMesh;
    Prism::Ref<Prism::Texture2D> m_BRDFLUT;

    Prism::Ref<Prism::MaterialInstance> m_MeshMaterial;
    Prism::Ref<Prism::MaterialInstance> m_GridMaterial;

    std::vector<Prism::Ref<Prism::MaterialInstance>> m_MetalSphereMaterialInstances;
    std::vector<Prism::Ref<Prism::MaterialInstance>> m_DielectricSphereMaterialInstances;

    float m_GridScale = 16.025f, m_GridSize = 0.025f;
    float m_MeshScale = 1.0f;

    Prism::Ref<Prism::Shader> m_Shader;
    Prism::Ref<Prism::Shader> m_PBRShader;

    struct AlbedoInput
    {
        glm::vec3 Color = { 0.972f, 0.96f, 0.915f }; // Silver, from https://docs.unrealengine.com/en-us/Engine/Rendering/Materials/PhysicallyBased
        Prism::Ref<Prism::Texture2D> TextureMap;
        bool SRGB = true;
        bool UseTexture = false;
    };
    AlbedoInput m_AlbedoInput;

    struct NormalInput
    {
        Prism::Ref<Prism::Texture2D> TextureMap;
        bool UseTexture = false;
    };
    NormalInput m_NormalInput;

    struct MetalnessInput
    {
        float Value = 1.0f;
        Prism::Ref<Prism::Texture2D> TextureMap;
        bool UseTexture = false;
    };
    MetalnessInput m_MetalnessInput;

    struct RoughnessInput
    {
        float Value = 0.5f;
        Prism::Ref<Prism::Texture2D> TextureMap;
        bool UseTexture = false;
    };
    RoughnessInput m_RoughnessInput;

    Prism::Ref<Prism::FrameBuffer> m_Framebuffer, m_FinalPresentBuffer;

    Prism::Ref<Prism::VertexBuffer> m_VertexBuffer;
    Prism::Ref<Prism::IndexBuffer> m_IndexBuffer;
    Prism::Ref<Prism::TextureCube> m_EnvironmentCubeMap, m_EnvironmentIrradiance;

    Prism::Camera m_Camera;

    struct Light
    {
        glm::vec3 Direction;
        glm::vec3 Radiance;
    };
    Light m_Light;
    float m_LightMultiplier = 0.3f;

    // PBR params
    float m_Exposure = 1.0f;

    bool m_RadiancePrefilter = false;

    float m_EnvMapRotation = 0.0f;

    enum class Scene : uint32_t
    {
        Spheres = 0, Model = 1
    };
    Scene m_Scene;

    // Editor resources
    Prism::Ref<Prism::Texture2D> m_CheckerboardTex;
};



#endif //DEMOLAYER_H