// Copyright 2015 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#pragma once

#include <array>
#include <memory>
#include <set>
#include <tuple>

#include <boost/icl/interval_map.hpp>
#include <glad/glad.h>

#include "common/assert.h"
#include "common/common_funcs.h"
#include "common/common_types.h"

#include "core/hw/gpu.h"

#include "video_core/pica.h"
#include "video_core/renderer_opengl/gl_resource_manager.h"

namespace MathUtil {
template <class T> struct Rectangle;
}

struct CachedSurface;

using SurfaceCache = boost::icl::interval_map<PAddr, std::set<std::shared_ptr<CachedSurface>>>;

struct CachedSurface {
    enum class PixelFormat {
        // First 5 formats are shared between textures and color buffers
        RGBA8        =  0,
        RGB8         =  1,
        RGB5A1       =  2,
        RGB565       =  3,
        RGBA4        =  4,

        // Texture-only formats
        IA8          =  5,
        RG8          =  6,
        I8           =  7,
        A8           =  8,
        IA4          =  9,
        I4           = 10,
        A4           = 11,
        ETC1         = 12,
        ETC1A4       = 13,

        // Depth buffer-only formats
        D16          = 14,
        // gap
        D24          = 16,
        D24S8        = 17,

        Invalid      = 255,
    };

    enum class SurfaceType {
        Color        = 0,
        Texture      = 1,
        Depth        = 2,
        DepthStencil = 3,
        Invalid      = 4,
    };

    static unsigned int GetFormatBpp(CachedSurface::PixelFormat format) {
        static const std::array<unsigned int, 18> bpp_table = {
            32, // RGBA8
            24, // RGB8
            16, // RGB5A1
            16, // RGB565
            16, // RGBA4
            16, // IA8
            16, // RG8
            8,  // I8
            8,  // A8
            8,  // IA4
            4,  // I4
            4,  // A4
            4,  // ETC1
            8,  // ETC1A4
            16, // D16
            0,
            24, // D24
            32, // D24S8
        };

        ASSERT((unsigned int)format < ARRAY_SIZE(bpp_table));
        return bpp_table[(unsigned int)format];
    }

    static PixelFormat PixelFormatFromTextureFormat(Pica::Regs::TextureFormat format) {
        return ((unsigned int)format < 14) ? (PixelFormat)format : PixelFormat::Invalid;
    }

    static PixelFormat PixelFormatFromColorFormat(Pica::Regs::ColorFormat format) {
        return ((unsigned int)format < 5) ? (PixelFormat)format : PixelFormat::Invalid;
    }

    static PixelFormat PixelFormatFromDepthFormat(Pica::Regs::DepthFormat format) {
        return ((unsigned int)format < 4) ? (PixelFormat)((unsigned int)format + 14) : PixelFormat::Invalid;
    }

    static PixelFormat PixelFormatFromGPUPixelFormat(GPU::Regs::PixelFormat format) {
        switch (format) {
        // RGB565 and RGB5A1 are switched in PixelFormat compared to ColorFormat
        case GPU::Regs::PixelFormat::RGB565:
            return PixelFormat::RGB565;
        case GPU::Regs::PixelFormat::RGB5A1:
            return PixelFormat::RGB5A1;
        default:
            return ((unsigned int)format < 5) ? (PixelFormat)format : PixelFormat::Invalid;
        }
    }

    static bool CheckFormatsBlittable(PixelFormat pixel_format_a, PixelFormat pixel_format_b) {
        SurfaceType a_type = GetFormatType(pixel_format_a);
        SurfaceType b_type = GetFormatType(pixel_format_b);

        if ((a_type == SurfaceType::Color || a_type == SurfaceType::Texture) && (b_type == SurfaceType::Color || b_type == SurfaceType::Texture)) {
            return true;
        }

        if (a_type == SurfaceType::Depth && b_type == SurfaceType::Depth) {
            return true;
        }

        if (a_type == SurfaceType::DepthStencil && b_type == SurfaceType::DepthStencil) {
            return true;
        }

        return false;
    }

    static SurfaceType GetFormatType(PixelFormat pixel_format) {
        if ((unsigned int)pixel_format < 5) {
            return SurfaceType::Color;
        }

        if ((unsigned int)pixel_format < 14) {
            return SurfaceType::Texture;
        }

        if (pixel_format == PixelFormat::D16 || pixel_format == PixelFormat::D24) {
            return SurfaceType::Depth;
        }

        if (pixel_format == PixelFormat::D24S8) {
            return SurfaceType::DepthStencil;
        }

        return SurfaceType::Invalid;
    }

    u32 GetScaledWidth() const {
        return (u32)(width * res_scale_width);
    }

    u32 GetScaledHeight() const {
        return (u32)(height * res_scale_height);
    }

    PAddr addr;
    u32 size;

    PAddr min_valid;
    PAddr max_valid;

    OGLTexture texture;
    u32 width;
    u32 height;
    u32 stride = 0;
    float res_scale_width = 1.f;
    float res_scale_height = 1.f;

    bool is_tiled;
    PixelFormat pixel_format;
    bool dirty;
};

class RasterizerCacheOpenGL : NonCopyable {
public:
    RasterizerCacheOpenGL();
    ~RasterizerCacheOpenGL();

    /// Blits one texture to another
    bool BlitTextures(GLuint src_tex, GLuint dst_tex, CachedSurface::SurfaceType type, const MathUtil::Rectangle<int>& src_rect, const MathUtil::Rectangle<int>& dst_rect);

    /// Attempt to blit one surface's texture to another
    bool TryBlitSurfaces(CachedSurface* src_surface, const MathUtil::Rectangle<int>& src_rect, CachedSurface* dst_surface, const MathUtil::Rectangle<int>& dst_rect);

    /// Loads a texture from 3DS memory to OpenGL and caches it (if not already cached)
    CachedSurface* GetSurface(const CachedSurface& params, bool match_res_scale, bool load_if_create);

    /// Attempt to find a subrect (resolution scaled) of a surface, otherwise loads a texture from 3DS memory to OpenGL and caches it (if not already cached)
    CachedSurface* GetSurfaceRect(const CachedSurface& params, bool match_res_scale, bool load_if_create, MathUtil::Rectangle<int>& out_rect);

    /// Gets a surface based on the texture configuration
    CachedSurface* GetTextureSurface(const Pica::Regs::FullTextureConfig& config);

    /// Gets the color and depth surfaces and rect (resolution scaled) based on the framebuffer configuration
    std::tuple<CachedSurface*, CachedSurface*, MathUtil::Rectangle<int>> GetFramebufferSurfaces(const Pica::Regs::FramebufferConfig& config);

    /// Attempt to get a surface that exactly matches the fill region and format
    CachedSurface* TryGetFillSurface(const GPU::Regs::MemoryFillConfig& config);

    /// Write the surface back to memory
    void FlushSurface(CachedSurface* surface);

    /// Write any cached resources overlapping the region back to memory (if dirty) and optionally invalidate them in the cache
    void FlushRegion(PAddr addr, u32 size, const CachedSurface* skip_surface, bool invalidate);

    /// Flush all cached resources tracked by this cache manager
    void FlushAll();

private:
    SurfaceCache surface_cache;
    OGLFramebuffer transfer_framebuffers[2];
};
