// Copyright 2018 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <algorithm>
#include <glad/glad.h>

#include "common/alignment.h"
#include "common/assert.h"
#include "common/microprofile.h"
#include "common/scope_exit.h"
#include "core/core.h"
#include "core/hle/kernel/process.h"
#include "core/memory.h"
#include "core/settings.h"
#include "video_core/engines/maxwell_3d.h"
#include "video_core/renderer_opengl/gl_rasterizer_cache.h"
#include "video_core/textures/astc.h"
#include "video_core/textures/decoders.h"
#include "video_core/utils.h"

using SurfaceType = SurfaceParams::SurfaceType;
using PixelFormat = SurfaceParams::PixelFormat;
using ComponentType = SurfaceParams::ComponentType;

struct FormatTuple {
    GLint internal_format;
    GLenum format;
    GLenum type;
    ComponentType component_type;
    bool compressed;
};

/*static*/ SurfaceParams SurfaceParams::CreateForTexture(
    const Tegra::Texture::FullTextureInfo& config) {

    SurfaceParams params{};
    params.addr = config.tic.Address();
    params.is_tiled = config.tic.IsTiled();
    params.block_height = params.is_tiled ? config.tic.BlockHeight() : 0,
    params.pixel_format = PixelFormatFromTextureFormat(config.tic.format);
    params.component_type = ComponentTypeFromTexture(config.tic.r_type.Value());
    params.type = GetFormatType(params.pixel_format);
    params.width = Common::AlignUp(config.tic.Width(), GetCompressionFactor(params.pixel_format));
    params.height = Common::AlignUp(config.tic.Height(), GetCompressionFactor(params.pixel_format));
    params.unaligned_height = config.tic.Height();
    params.size_in_bytes = params.SizeInBytes();
    return params;
}

/*static*/ SurfaceParams SurfaceParams::CreateForFramebuffer(
    const Tegra::Engines::Maxwell3D::Regs::RenderTargetConfig& config) {

    SurfaceParams params{};
    params.addr = config.Address();
    params.is_tiled = true;
    params.block_height = Tegra::Texture::TICEntry::DefaultBlockHeight;
    params.pixel_format = PixelFormatFromRenderTargetFormat(config.format);
    params.component_type = ComponentTypeFromRenderTarget(config.format);
    params.type = GetFormatType(params.pixel_format);
    params.width = config.width;
    params.height = config.height;
    params.unaligned_height = config.height;
    params.size_in_bytes = params.SizeInBytes();
    return params;
}

static constexpr std::array<FormatTuple, SurfaceParams::MaxPixelFormat> tex_format_tuples = {{
    {GL_RGBA8, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, ComponentType::UNorm, false}, // ABGR8
    {GL_RGB, GL_RGB, GL_UNSIGNED_SHORT_5_6_5_REV, ComponentType::UNorm, false},    // B5G6R5
    {GL_RGB10_A2, GL_RGBA, GL_UNSIGNED_INT_2_10_10_10_REV, ComponentType::UNorm,
     false}, // A2B10G10R10
    {GL_RGB5_A1, GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, ComponentType::UNorm, false}, // A1B5G5R5
    {GL_R8, GL_RED, GL_UNSIGNED_BYTE, ComponentType::UNorm, false},                    // R8
    {GL_RGBA16F, GL_RGBA, GL_HALF_FLOAT, ComponentType::Float, false},                 // RGBA16F
    {GL_R11F_G11F_B10F, GL_RGB, GL_UNSIGNED_INT_10F_11F_11F_REV, ComponentType::Float,
     false},                                                                     // R11FG11FB10F
    {GL_RGBA32UI, GL_RGBA_INTEGER, GL_UNSIGNED_INT, ComponentType::UInt, false}, // RGBA32UI
    {GL_COMPRESSED_RGB_S3TC_DXT1_EXT, GL_RGB, GL_UNSIGNED_INT_8_8_8_8, ComponentType::UNorm,
     true}, // DXT1
    {GL_COMPRESSED_RGBA_S3TC_DXT3_EXT, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, ComponentType::UNorm,
     true}, // DXT23
    {GL_COMPRESSED_RGBA_S3TC_DXT5_EXT, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, ComponentType::UNorm,
     true},                                                                                 // DXT45
    {GL_COMPRESSED_RED_RGTC1, GL_RED, GL_UNSIGNED_INT_8_8_8_8, ComponentType::UNorm, true}, // DXN1
    {GL_RGBA8, GL_RGBA, GL_UNSIGNED_BYTE, ComponentType::UNorm, false}, // ASTC_2D_4X4

    // DepthStencil formats
    {GL_DEPTH24_STENCIL8, GL_DEPTH_STENCIL, GL_UNSIGNED_INT_24_8, ComponentType::UNorm,
     false}, // Z24S8
}};

static const FormatTuple& GetFormatTuple(PixelFormat pixel_format, ComponentType component_type) {
    ASSERT(static_cast<size_t>(pixel_format) < tex_format_tuples.size());
    auto& format = tex_format_tuples[static_cast<unsigned int>(pixel_format)];
    ASSERT(component_type == format.component_type);

    return format;
}

VAddr SurfaceParams::GetCpuAddr() const {
    const auto& gpu = Core::System::GetInstance().GPU();
    return *gpu.memory_manager->GpuToCpuAddress(addr);
}

static bool IsPixelFormatASTC(PixelFormat format) {
    switch (format) {
    case PixelFormat::ASTC_2D_4X4:
        return true;
    default:
        return false;
    }
}

static std::pair<u32, u32> GetASTCBlockSize(PixelFormat format) {
    switch (format) {
    case PixelFormat::ASTC_2D_4X4:
        return {4, 4};
    default:
        LOG_CRITICAL(HW_GPU, "Unhandled format: {}", static_cast<u32>(format));
        UNREACHABLE();
    }
}

MathUtil::Rectangle<u32> SurfaceParams::GetRect() const {
    u32 actual_height{unaligned_height};
    if (IsPixelFormatASTC(pixel_format)) {
        // ASTC formats must stop at the ATSC block size boundary
        actual_height = Common::AlignDown(actual_height, GetASTCBlockSize(pixel_format).second);
    }
    return {0, actual_height, width, 0};
}

static void ConvertASTCToRGBA8(std::vector<u8>& data, PixelFormat format, u32 width, u32 height) {
    u32 block_width{};
    u32 block_height{};
    std::tie(block_width, block_height) = GetASTCBlockSize(format);
    data = Tegra::Texture::ASTC::Decompress(data, width, height, block_width, block_height);
}

template <bool morton_to_gl, PixelFormat format>
void MortonCopy(u32 stride, u32 block_height, u32 height, u8* gl_buffer, Tegra::GPUVAddr addr) {
    constexpr u32 bytes_per_pixel = SurfaceParams::GetFormatBpp(format) / CHAR_BIT;
    constexpr u32 gl_bytes_per_pixel = CachedSurface::GetGLBytesPerPixel(format);
    const auto& gpu = Core::System::GetInstance().GPU();

    if (morton_to_gl) {
        if (SurfaceParams::GetFormatType(format) == SurfaceType::ColorTexture) {
            auto data = Tegra::Texture::UnswizzleTexture(
                *gpu.memory_manager->GpuToCpuAddress(addr),
                SurfaceParams::TextureFormatFromPixelFormat(format), stride, height, block_height);
            std::memcpy(gl_buffer, data.data(), data.size());
        } else {
            auto data = Tegra::Texture::UnswizzleDepthTexture(
                *gpu.memory_manager->GpuToCpuAddress(addr),
                SurfaceParams::DepthFormatFromPixelFormat(format), stride, height, block_height);
            std::memcpy(gl_buffer, data.data(), data.size());
        }
    } else {
        // TODO(bunnei): Assumes the default rendering GOB size of 16 (128 lines). We should
        // check the configuration for this and perform more generic un/swizzle
        LOG_WARNING(Render_OpenGL, "need to use correct swizzle/GOB parameters!");
        VideoCore::MortonCopyPixels128(
            stride, height, bytes_per_pixel, gl_bytes_per_pixel,
            Memory::GetPointer(*gpu.memory_manager->GpuToCpuAddress(addr)), gl_buffer,
            morton_to_gl);
    }
}

static constexpr std::array<void (*)(u32, u32, u32, u8*, Tegra::GPUVAddr),
                            SurfaceParams::MaxPixelFormat>
    morton_to_gl_fns = {
        MortonCopy<true, PixelFormat::ABGR8>,        MortonCopy<true, PixelFormat::B5G6R5>,
        MortonCopy<true, PixelFormat::A2B10G10R10>,  MortonCopy<true, PixelFormat::A1B5G5R5>,
        MortonCopy<true, PixelFormat::R8>,           MortonCopy<true, PixelFormat::RGBA16F>,
        MortonCopy<true, PixelFormat::R11FG11FB10F>, MortonCopy<true, PixelFormat::RGBA32UI>,
        MortonCopy<true, PixelFormat::DXT1>,         MortonCopy<true, PixelFormat::DXT23>,
        MortonCopy<true, PixelFormat::DXT45>,        MortonCopy<true, PixelFormat::DXN1>,
        MortonCopy<true, PixelFormat::ASTC_2D_4X4>,  MortonCopy<true, PixelFormat::Z24S8>,
};

static constexpr std::array<void (*)(u32, u32, u32, u8*, Tegra::GPUVAddr),
                            SurfaceParams::MaxPixelFormat>
    gl_to_morton_fns = {
        MortonCopy<false, PixelFormat::ABGR8>,
        MortonCopy<false, PixelFormat::B5G6R5>,
        MortonCopy<false, PixelFormat::A2B10G10R10>,
        MortonCopy<false, PixelFormat::A1B5G5R5>,
        MortonCopy<false, PixelFormat::R8>,
        MortonCopy<false, PixelFormat::RGBA16F>,
        MortonCopy<false, PixelFormat::R11FG11FB10F>,
        MortonCopy<false, PixelFormat::RGBA32UI>,
        // TODO(Subv): Swizzling the DXT1/DXT23/DXT45/DXN1 formats is not yet supported
        nullptr,
        nullptr,
        nullptr,
        nullptr,
        MortonCopy<false, PixelFormat::ABGR8>,
        MortonCopy<false, PixelFormat::Z24S8>,
};

// Allocate an uninitialized texture of appropriate size and format for the surface
static void AllocateSurfaceTexture(GLuint texture, const FormatTuple& format_tuple, u32 width,
                                   u32 height) {
    OpenGLState cur_state = OpenGLState::GetCurState();

    // Keep track of previous texture bindings
    GLuint old_tex = cur_state.texture_units[0].texture_2d;
    cur_state.texture_units[0].texture_2d = texture;
    cur_state.Apply();
    glActiveTexture(GL_TEXTURE0);

    if (!format_tuple.compressed) {
        // Only pre-create the texture for non-compressed textures.
        glTexImage2D(GL_TEXTURE_2D, 0, format_tuple.internal_format, width, height, 0,
                     format_tuple.format, format_tuple.type, nullptr);
    }

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    // Restore previous texture bindings
    cur_state.texture_units[0].texture_2d = old_tex;
    cur_state.Apply();
}

CachedSurface::CachedSurface(const SurfaceParams& params) : params(params) {
    texture.Create();
    const auto& rect{params.GetRect()};
    AllocateSurfaceTexture(texture.handle,
                           GetFormatTuple(params.pixel_format, params.component_type),
                           rect.GetWidth(), rect.GetHeight());
}

MICROPROFILE_DEFINE(OpenGL_SurfaceLoad, "OpenGL", "Surface Load", MP_RGB(128, 64, 192));
void CachedSurface::LoadGLBuffer() {
    ASSERT(params.type != SurfaceType::Fill);

    u8* const texture_src_data = Memory::GetPointer(params.GetCpuAddr());

    ASSERT(texture_src_data);

    gl_buffer.resize(params.width * params.height * GetGLBytesPerPixel(params.pixel_format));

    MICROPROFILE_SCOPE(OpenGL_SurfaceLoad);

    if (!params.is_tiled) {
        const u32 bytes_per_pixel{params.GetFormatBpp() >> 3};

        std::memcpy(gl_buffer.data(), texture_src_data,
                    bytes_per_pixel * params.width * params.height);
    } else {
        morton_to_gl_fns[static_cast<size_t>(params.pixel_format)](
            params.width, params.block_height, params.height, gl_buffer.data(), params.addr);
    }

    if (IsPixelFormatASTC(params.pixel_format)) {
        // ASTC formats are converted to RGBA8 in software, as most PC GPUs do not support this
        ConvertASTCToRGBA8(gl_buffer, params.pixel_format, params.width, params.height);
    }
}

MICROPROFILE_DEFINE(OpenGL_SurfaceFlush, "OpenGL", "Surface Flush", MP_RGB(128, 192, 64));
void CachedSurface::FlushGLBuffer() {
    u8* const dst_buffer = Memory::GetPointer(params.GetCpuAddr());

    ASSERT(dst_buffer);
    ASSERT(gl_buffer.size() ==
           params.width * params.height * GetGLBytesPerPixel(params.pixel_format));

    MICROPROFILE_SCOPE(OpenGL_SurfaceFlush);

    if (!params.is_tiled) {
        std::memcpy(dst_buffer, gl_buffer.data(), params.size_in_bytes);
    } else {
        gl_to_morton_fns[static_cast<size_t>(params.pixel_format)](
            params.width, params.block_height, params.height, gl_buffer.data(), params.addr);
    }
}

MICROPROFILE_DEFINE(OpenGL_TextureUL, "OpenGL", "Texture Upload", MP_RGB(128, 64, 192));
void CachedSurface::UploadGLTexture(GLuint read_fb_handle, GLuint draw_fb_handle) {
    if (params.type == SurfaceType::Fill)
        return;

    MICROPROFILE_SCOPE(OpenGL_TextureUL);

    ASSERT(gl_buffer.size() ==
           params.width * params.height * GetGLBytesPerPixel(params.pixel_format));

    const auto& rect{params.GetRect()};

    // Load data from memory to the surface
    GLint x0 = static_cast<GLint>(rect.left);
    GLint y0 = static_cast<GLint>(rect.bottom);
    size_t buffer_offset = (y0 * params.width + x0) * GetGLBytesPerPixel(params.pixel_format);

    const FormatTuple& tuple = GetFormatTuple(params.pixel_format, params.component_type);
    GLuint target_tex = texture.handle;
    OpenGLState cur_state = OpenGLState::GetCurState();

    GLuint old_tex = cur_state.texture_units[0].texture_2d;
    cur_state.texture_units[0].texture_2d = target_tex;
    cur_state.Apply();

    // Ensure no bad interactions with GL_UNPACK_ALIGNMENT
    ASSERT(params.width * GetGLBytesPerPixel(params.pixel_format) % 4 == 0);
    glPixelStorei(GL_UNPACK_ROW_LENGTH, static_cast<GLint>(params.width));

    glActiveTexture(GL_TEXTURE0);
    if (tuple.compressed) {
        glCompressedTexImage2D(
            GL_TEXTURE_2D, 0, tuple.internal_format, static_cast<GLsizei>(params.width),
            static_cast<GLsizei>(params.height), 0, static_cast<GLsizei>(params.size_in_bytes),
            &gl_buffer[buffer_offset]);
    } else {
        glTexSubImage2D(GL_TEXTURE_2D, 0, x0, y0, static_cast<GLsizei>(rect.GetWidth()),
                        static_cast<GLsizei>(rect.GetHeight()), tuple.format, tuple.type,
                        &gl_buffer[buffer_offset]);
    }

    glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);

    cur_state.texture_units[0].texture_2d = old_tex;
    cur_state.Apply();
}

MICROPROFILE_DEFINE(OpenGL_TextureDL, "OpenGL", "Texture Download", MP_RGB(128, 192, 64));
void CachedSurface::DownloadGLTexture(GLuint read_fb_handle, GLuint draw_fb_handle) {
    if (params.type == SurfaceType::Fill)
        return;

    MICROPROFILE_SCOPE(OpenGL_TextureDL);

    gl_buffer.resize(params.width * params.height * GetGLBytesPerPixel(params.pixel_format));

    OpenGLState state = OpenGLState::GetCurState();
    OpenGLState prev_state = state;
    SCOPE_EXIT({ prev_state.Apply(); });

    const FormatTuple& tuple = GetFormatTuple(params.pixel_format, params.component_type);

    // Ensure no bad interactions with GL_PACK_ALIGNMENT
    ASSERT(params.width * GetGLBytesPerPixel(params.pixel_format) % 4 == 0);
    glPixelStorei(GL_PACK_ROW_LENGTH, static_cast<GLint>(params.width));

    const auto& rect{params.GetRect()};
    size_t buffer_offset =
        (rect.bottom * params.width + rect.left) * GetGLBytesPerPixel(params.pixel_format);

    state.UnbindTexture(texture.handle);
    state.draw.read_framebuffer = read_fb_handle;
    state.Apply();

    if (params.type == SurfaceType::ColorTexture) {
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                               texture.handle, 0);
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, 0,
                               0);
    } else if (params.type == SurfaceType::Depth) {
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D,
                               texture.handle, 0);
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_TEXTURE_2D, 0, 0);
    } else {
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, 0, 0);
        glFramebufferTexture2D(GL_READ_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D,
                               texture.handle, 0);
    }
    glReadPixels(static_cast<GLint>(rect.left), static_cast<GLint>(rect.bottom),
                 static_cast<GLsizei>(rect.GetWidth()), static_cast<GLsizei>(rect.GetHeight()),
                 tuple.format, tuple.type, &gl_buffer[buffer_offset]);

    glPixelStorei(GL_PACK_ROW_LENGTH, 0);
}

RasterizerCacheOpenGL::RasterizerCacheOpenGL() {
    read_framebuffer.Create();
    draw_framebuffer.Create();
}

RasterizerCacheOpenGL::~RasterizerCacheOpenGL() {
    while (!surface_cache.empty()) {
        UnregisterSurface(surface_cache.begin()->second);
    }
}

Surface RasterizerCacheOpenGL::GetTextureSurface(const Tegra::Texture::FullTextureInfo& config) {
    return GetSurface(SurfaceParams::CreateForTexture(config));
}

SurfaceSurfaceRect_Tuple RasterizerCacheOpenGL::GetFramebufferSurfaces(
    bool using_color_fb, bool using_depth_fb, const MathUtil::Rectangle<s32>& viewport) {
    const auto& regs = Core::System().GetInstance().GPU().Maxwell3D().regs;

    // TODO(bunnei): This is hard corded to use just the first render buffer
    LOG_WARNING(Render_OpenGL, "hard-coded for render target 0!");

    // get color and depth surfaces
    const SurfaceParams color_params{SurfaceParams::CreateForFramebuffer(regs.rt[0])};
    SurfaceParams depth_params{color_params};

    if (using_depth_fb) {
        depth_params.addr = regs.zeta.Address();
        depth_params.pixel_format = SurfaceParams::PixelFormatFromDepthFormat(regs.zeta.format);
        depth_params.component_type = SurfaceParams::ComponentTypeFromDepthFormat(regs.zeta.format);
        depth_params.type = SurfaceParams::GetFormatType(depth_params.pixel_format);
        depth_params.size_in_bytes = depth_params.SizeInBytes();
    }

    MathUtil::Rectangle<u32> color_rect{};
    Surface color_surface;
    if (using_color_fb) {
        color_surface = GetSurface(color_params);
        if (color_surface) {
            color_rect = color_surface->GetSurfaceParams().GetRect();
        }
    }

    MathUtil::Rectangle<u32> depth_rect{};
    Surface depth_surface;
    if (using_depth_fb) {
        depth_surface = GetSurface(depth_params);
        if (depth_surface) {
            depth_rect = depth_surface->GetSurfaceParams().GetRect();
        }
    }

    MathUtil::Rectangle<u32> fb_rect{};
    if (color_surface && depth_surface) {
        fb_rect = color_rect;
        // Color and Depth surfaces must have the same dimensions and offsets
        if (color_rect.bottom != depth_rect.bottom || color_rect.top != depth_rect.top ||
            color_rect.left != depth_rect.left || color_rect.right != depth_rect.right) {
            color_surface = GetSurface(color_params);
            depth_surface = GetSurface(depth_params);
            fb_rect = color_surface->GetSurfaceParams().GetRect();
        }
    } else if (color_surface) {
        fb_rect = color_rect;
    } else if (depth_surface) {
        fb_rect = depth_rect;
    }

    return std::make_tuple(color_surface, depth_surface, fb_rect);
}

void RasterizerCacheOpenGL::LoadSurface(const Surface& surface) {
    surface->LoadGLBuffer();
    surface->UploadGLTexture(read_framebuffer.handle, draw_framebuffer.handle);
}

void RasterizerCacheOpenGL::MarkSurfaceAsDirty(const Surface& surface) {
    if (Settings::values.use_accurate_framebuffers) {
        // If enabled, always flush dirty surfaces
        surface->DownloadGLTexture(read_framebuffer.handle, draw_framebuffer.handle);
        surface->FlushGLBuffer();
    } else {
        // Otherwise, don't mark surfaces that we write to as cached, because the resulting loads
        // and flushes are very slow and do not seem to improve accuracy
        const auto& params{surface->GetSurfaceParams()};
        Memory::RasterizerMarkRegionCached(params.addr, params.size_in_bytes, false);
    }
}

Surface RasterizerCacheOpenGL::GetSurface(const SurfaceParams& params) {
    if (params.addr == 0 || params.height * params.width == 0) {
        return {};
    }

    const auto& gpu = Core::System::GetInstance().GPU();
    // Don't try to create any entries in the cache if the address of the texture is invalid.
    if (gpu.memory_manager->GpuToCpuAddress(params.addr) == boost::none)
        return {};

    // Check for an exact match in existing surfaces
    const auto& surface_key{SurfaceKey::Create(params)};
    const auto& search{surface_cache.find(surface_key)};
    Surface surface;
    if (search != surface_cache.end()) {
        surface = search->second;
        if (Settings::values.use_accurate_framebuffers) {
            // Reload the surface from Switch memory
            LoadSurface(surface);
        }
    } else {
        surface = std::make_shared<CachedSurface>(params);
        RegisterSurface(surface);
        LoadSurface(surface);
    }

    return surface;
}

Surface RasterizerCacheOpenGL::TryFindFramebufferSurface(VAddr cpu_addr) const {
    // Tries to find the GPU address of a framebuffer based on the CPU address. This is because
    // final output framebuffers are specified by CPU address, but internally our GPU cache uses
    // GPU addresses. We iterate through all cached framebuffers, and compare their starting CPU
    // address to the one provided. This is obviously not great, and won't work if the
    // framebuffer overlaps surfaces.

    std::vector<Surface> surfaces;
    for (const auto& surface : surface_cache) {
        const auto& params = surface.second->GetSurfaceParams();
        const VAddr surface_cpu_addr = params.GetCpuAddr();
        if (cpu_addr >= surface_cpu_addr && cpu_addr < (surface_cpu_addr + params.size_in_bytes)) {
            ASSERT_MSG(cpu_addr == surface_cpu_addr, "overlapping surfaces are unsupported");
            surfaces.push_back(surface.second);
        }
    }

    if (surfaces.empty()) {
        return {};
    }

    ASSERT_MSG(surfaces.size() == 1, ">1 surface is unsupported");

    return surfaces[0];
}

void RasterizerCacheOpenGL::FlushRegion(Tegra::GPUVAddr /*addr*/, size_t /*size*/) {
    // TODO(bunnei): This is unused in the current implementation of the rasterizer cache. We should
    // probably implement this in the future, but for now, the `use_accurate_framebufers` setting
    // can be used to always flush.
}

void RasterizerCacheOpenGL::InvalidateRegion(Tegra::GPUVAddr addr, size_t size) {
    for (const auto& pair : surface_cache) {
        const auto& surface{pair.second};
        const auto& params{surface->GetSurfaceParams()};

        if (params.IsOverlappingRegion(addr, size)) {
            UnregisterSurface(surface);
        }
    }
}

void RasterizerCacheOpenGL::RegisterSurface(const Surface& surface) {
    const auto& params{surface->GetSurfaceParams()};
    const auto& surface_key{SurfaceKey::Create(params)};
    const auto& search{surface_cache.find(surface_key)};

    if (search != surface_cache.end()) {
        // Registered already
        return;
    }

    surface_cache[surface_key] = surface;
    UpdatePagesCachedCount(params.addr, params.size_in_bytes, 1);
}

void RasterizerCacheOpenGL::UnregisterSurface(const Surface& surface) {
    const auto& params{surface->GetSurfaceParams()};
    const auto& surface_key{SurfaceKey::Create(params)};
    const auto& search{surface_cache.find(surface_key)};

    if (search == surface_cache.end()) {
        // Unregistered already
        return;
    }

    UpdatePagesCachedCount(params.addr, params.size_in_bytes, -1);
    surface_cache.erase(search);
}

template <typename Map, typename Interval>
constexpr auto RangeFromInterval(Map& map, const Interval& interval) {
    return boost::make_iterator_range(map.equal_range(interval));
}

void RasterizerCacheOpenGL::UpdatePagesCachedCount(Tegra::GPUVAddr addr, u64 size, int delta) {
    const u64 num_pages = ((addr + size - 1) >> Tegra::MemoryManager::PAGE_BITS) -
                          (addr >> Tegra::MemoryManager::PAGE_BITS) + 1;
    const u64 page_start = addr >> Tegra::MemoryManager::PAGE_BITS;
    const u64 page_end = page_start + num_pages;

    // Interval maps will erase segments if count reaches 0, so if delta is negative we have to
    // subtract after iterating
    const auto pages_interval = PageMap::interval_type::right_open(page_start, page_end);
    if (delta > 0)
        cached_pages.add({pages_interval, delta});

    for (const auto& pair : RangeFromInterval(cached_pages, pages_interval)) {
        const auto interval = pair.first & pages_interval;
        const int count = pair.second;

        const Tegra::GPUVAddr interval_start_addr = boost::icl::first(interval)
                                                    << Tegra::MemoryManager::PAGE_BITS;
        const Tegra::GPUVAddr interval_end_addr = boost::icl::last_next(interval)
                                                  << Tegra::MemoryManager::PAGE_BITS;
        const u64 interval_size = interval_end_addr - interval_start_addr;

        if (delta > 0 && count == delta)
            Memory::RasterizerMarkRegionCached(interval_start_addr, interval_size, true);
        else if (delta < 0 && count == -delta)
            Memory::RasterizerMarkRegionCached(interval_start_addr, interval_size, false);
        else
            ASSERT(count >= 0);
    }

    if (delta < 0)
        cached_pages.add({pages_interval, delta});
}
