//  SPDX-License-Identifier: MIT
//
//  ES-DE Frontend
//  Renderer.h
//
//  Generic rendering functions.
//

#ifndef ES_CORE_RENDERER_RENDERER_H
#define ES_CORE_RENDERER_RENDERER_H

#include "Log.h"
#include "utils/MathUtil.h"

#include <stack>
#include <string>
#include <vector>

struct SDL_Window;

class Renderer
{
public:
    enum class TextureType {
        RGBA,
        BGRA,
        RED
    };

    enum class BlendFactor {
        ZERO,
        ONE,
        SRC_COLOR,
        ONE_MINUS_SRC_COLOR,
        SRC_ALPHA,
        ONE_MINUS_SRC_ALPHA,
        DST_COLOR,
        ONE_MINUS_DST_COLOR,
        DST_ALPHA,
        ONE_MINUS_DST_ALPHA
    };

    // clang-format off
    enum Shader {
        CORE            = 0x00000001,
        BLUR_HORIZONTAL = 0x00000002,
        BLUR_VERTICAL   = 0x00000004,
        SCANLINES       = 0x00000008
    };

    enum ShaderFlags {
        PREMULTIPLIED         = 0x00000001,
        FONT_TEXTURE          = 0x00000002,
        POST_PROCESSING       = 0x00000004,
        CLIPPING              = 0x00000008,
        ROTATED               = 0x00000010, // Screen rotated 90 or 270 degrees.
        ROUNDED_CORNERS       = 0x00000020,
        ROUNDED_CORNERS_NO_AA = 0x00000040,
        CONVERT_PIXEL_FORMAT  = 0x00000080
    };
    // clang-format on

    struct Vertex {
        glm::vec2 position;
        glm::vec2 texcoord;
        unsigned int color;
        glm::vec4 clipRegion;
        float brightness;
        float opacity;
        float saturation;
        float dimming;
        float cornerRadius;
        float reflectionsFalloff;
        float blurStrength;
        unsigned int shaders;
        unsigned int shaderFlags;

        Vertex()
            : position {0.0f, 0.0f}
            , texcoord {0.0f, 0.0f}
            , color {0x00000000}
            , clipRegion {0.0f, 0.0f, 0.0f, 0.0f}
            , brightness {0.0f}
            , opacity {1.0f}
            , saturation {1.0f}
            , dimming {1.0f}
            , cornerRadius {0.0f}
            , reflectionsFalloff {0.0f}
            , blurStrength {0.0f}
            , shaders {0}
            , shaderFlags {0}
        {
        }

        Vertex(const glm::vec2& positionArg,
               const glm::vec2& texcoordArg,
               const unsigned int colorArg)
            : position {positionArg}
            , texcoord {texcoordArg}
            , color {colorArg}
            , clipRegion {0.0f, 0.0f, 0.0f, 0.0f}
            , brightness {0.0f}
            , opacity {1.0f}
            , saturation {1.0f}
            , dimming {1.0f}
            , cornerRadius {0.0f}
            , reflectionsFalloff {0.0f}
            , blurStrength {0.0f}
            , shaders {0}
            , shaderFlags {0}
        {
        }
    };

    struct postProcessingParams {
        float opacity;
        float saturation;
        float dimming;
        float blurStrength;
        unsigned int blurPasses;
        unsigned int shaders;

        postProcessingParams()
            : opacity {1.0f}
            , saturation {1.0f}
            , dimming {1.0f}
            , blurStrength {0.0f}
            , blurPasses {1}
            , shaders {0}
        {
        }
    };

    struct Rect {
        int x;
        int y;
        int w;
        int h;

        Rect()
            : x(0)
            , y(0)
            , w(0)
            , h(0)
        {
        }

        Rect(const int xValue, const int yValue, const int wValue, const int hValue)
            : x(xValue)
            , y(yValue)
            , w(wValue)
            , h(hValue)
        {
        }
    };

    static Renderer* getInstance();

    void setIcon();
    bool createWindow();
    void destroyWindow();
    bool init();
    void deinit();

    virtual bool loadShaders() = 0;

    void pushClipRect(const glm::ivec2& pos, const glm::ivec2& size);
    void popClipRect();

    void drawRect(const float x,
                  const float y,
                  const float w,
                  const float h,
                  const unsigned int color,
                  const unsigned int colorEnd,
                  const bool horizontalGradient = false,
                  const float opacity = 1.0f,
                  const float dimming = 1.0f,
                  const BlendFactor srcBlendFactor = BlendFactor::SRC_ALPHA,
                  const BlendFactor dstBlendFactor = BlendFactor::ONE_MINUS_SRC_ALPHA,
                  const float cornerRadius = 0.0f);

    const glm::mat4& getProjectionMatrix() { return mProjectionMatrix; }
    const glm::mat4& getProjectionMatrixNormal() { return mProjectionMatrixNormal; }
    SDL_Window* getSDLWindow() { return mSDLWindow; }
    const int getDisplayIndex() { return mDisplayIndex; }
    const int getScreenRotation() { return mScreenRotation; }
    static const bool getIsVerticalOrientation() { return sIsVerticalOrientation; }
    static const float getScreenWidth() { return static_cast<float>(sScreenWidth); }
    static const float getScreenHeight() { return static_cast<float>(sScreenHeight); }
    static const float getScreenWidthModifier() { return sScreenWidthModifier; }
    static const float getScreenHeightModifier() { return sScreenHeightModifier; }
    static const float getScreenAspectRatio() { return sScreenAspectRatio; }
    static const float getScreenResolutionModifier() { return sScreenResolutionModifier; }

    static constexpr glm::mat4 getIdentity() { return glm::mat4 {1.0f}; }
    glm::mat4 mTrans {getIdentity()};

    virtual void setup() = 0;
    virtual bool createContext() = 0;
    virtual void destroyContext() = 0;
    virtual unsigned int createTexture(const unsigned int texUnit,
                                       const TextureType type,
                                       const bool linearMinify,
                                       const bool linearMagnify,
                                       const bool mipmapping,
                                       const bool repeat,
                                       const unsigned int width,
                                       const unsigned int height,
                                       void* data) = 0;
    virtual void destroyTexture(const unsigned int texture) = 0;
    virtual void updateTexture(const unsigned int texture,
                               const unsigned int texUnit,
                               const TextureType type,
                               const unsigned int x,
                               const unsigned int y,
                               const unsigned int width,
                               const unsigned int height,
                               void* data) = 0;
    virtual void bindTexture(const unsigned int texture, const unsigned int texUnit) = 0;
    virtual void drawTriangleStrips(
        const Vertex* vertices,
        const unsigned int numVertices,
        const BlendFactor srcBlendFactor = BlendFactor::ONE,
        const BlendFactor dstBlendFactor = BlendFactor::ONE_MINUS_SRC_ALPHA) = 0;
    virtual void shaderPostprocessing(
        const unsigned int shaders,
        const Renderer::postProcessingParams& parameters = postProcessingParams(),
        unsigned char* textureRGBA = nullptr) = 0;
    virtual void setMatrix(const glm::mat4& matrix) = 0;
    virtual void setViewport(const Rect& viewport) = 0;
    virtual void setScissor(const Rect& scissor) = 0;
    virtual void setSwapInterval() = 0;
    virtual void swapBuffers() = 0;

protected:
    Rect mViewport;
    int mWindowWidth {0};
    int mWindowHeight {0};
    int mPaddingWidth {0};
    int mPaddingHeight {0};
    int mScreenOffsetX {0};
    int mScreenOffsetY {0};

private:
    std::stack<Rect> mClipStack;
    SDL_Window* mSDLWindow {nullptr};
    glm::mat4 mProjectionMatrix {};
    glm::mat4 mProjectionMatrixNormal {};

    static inline int sScreenWidth {0};
    static inline int sScreenHeight {0};
    int mDisplayIndex {0};
    int mScreenRotation {0};
    bool mInitialCursorState {true};
    static inline bool sIsVerticalOrientation {false};
    // Screen resolution modifiers relative to the 1920x1080 reference.
    static inline float sScreenHeightModifier {0.0f};
    static inline float sScreenWidthModifier {0.0f};
    static inline float sScreenAspectRatio {0.0f};
    static inline float sScreenResolutionModifier {0.0f};
};

#endif // ES_CORE_RENDERER_RENDERER_H