// Copyright 2020 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#pragma once

#include <condition_variable>
#include <deque>
#include <memory>
#include <shared_mutex>
#include <thread>
#include "common/bit_field.h"
#include "common/common_types.h"
#include "video_core/renderer_opengl/gl_device.h"
#include "video_core/renderer_opengl/gl_resource_manager.h"
#include "video_core/renderer_opengl/gl_shader_decompiler.h"

namespace Core::Frontend {
class EmuWindow;
class GraphicsContext;
} // namespace Core::Frontend

namespace Tegra {
class GPU;
}

namespace VideoCommon::Shader {

class AsyncShaders {
public:
    enum class Backend {
        OpenGL,
        GLASM,
    };

    struct ResultPrograms {
        OpenGL::OGLProgram opengl;
        OpenGL::OGLAssemblyProgram glasm;
    };

    struct Result {
        u64 uid;
        VAddr cpu_address;
        Backend backend;
        ResultPrograms program;
        std::vector<u64> code;
        std::vector<u64> code_b;
        Tegra::Engines::ShaderType shader_type;
    };

    explicit AsyncShaders(Core::Frontend::EmuWindow& emu_window);
    ~AsyncShaders();

    /// Start up shader worker threads
    void AllocateWorkers(std::size_t num_workers);

    /// Clear the shader queue and kill all worker threads
    void FreeWorkers();

    // Force end all threads
    void KillWorkers();

    /// Check to see if any shaders have actually been compiled
    bool HasCompletedWork();

    /// Deduce if a shader can be build on another thread of MUST be built in sync. We cannot build
    /// every shader async as some shaders are only built and executed once. We try to "guess" which
    /// shader would be used only once
    bool IsShaderAsync(const Tegra::GPU& gpu) const;

    /// Pulls completed compiled shaders
    std::vector<Result> GetCompletedWork();

    void QueueOpenGLShader(const OpenGL::Device& device, Tegra::Engines::ShaderType shader_type,
                           u64 uid, std::vector<u64> code, std::vector<u64> code_b, u32 main_offset,
                           VideoCommon::Shader::CompilerSettings compiler_settings,
                           const VideoCommon::Shader::Registry& registry, VAddr cpu_addr);

private:
    void ShaderCompilerThread(Core::Frontend::GraphicsContext* context);

    /// Check our worker queue to see if we have any work queued already
    bool HasWorkQueued();

    struct WorkerParams {
        AsyncShaders::Backend backend;
        OpenGL::Device device;
        Tegra::Engines::ShaderType shader_type;
        u64 uid;
        std::vector<u64> code;
        std::vector<u64> code_b;
        u32 main_offset;
        VideoCommon::Shader::CompilerSettings compiler_settings;
        VideoCommon::Shader::Registry registry;
        VAddr cpu_address;
    };

    std::condition_variable cv;
    std::mutex queue_mutex;
    std::shared_mutex completed_mutex;
    std::atomic<bool> is_thread_exiting{};
    std::vector<std::unique_ptr<Core::Frontend::GraphicsContext>> context_list;
    std::vector<std::thread> worker_threads;
    std::deque<WorkerParams> pending_queue;
    std::vector<AsyncShaders::Result> finished_work;
    Core::Frontend::EmuWindow& emu_window;
};

} // namespace VideoCommon::Shader