// Copyright 2023 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#pragma once

#include "core/hle/service/gsp/gsp_interrupt.h"
#include "video_core/pica/geometry_pipeline.h"
#include "video_core/pica/packed_attribute.h"
#include "video_core/pica/primitive_assembly.h"
#include "video_core/pica/regs_external.h"
#include "video_core/pica/regs_internal.h"
#include "video_core/pica/regs_lcd.h"
#include "video_core/pica/shader_setup.h"
#include "video_core/pica/shader_unit.h"

namespace Memory {
class MemorySystem;
}

namespace VideoCore {
class RasterizerInterface;
}

namespace Pica {

class DebugContext;
class ShaderEngine;

class PicaCore {
public:
    explicit PicaCore(Memory::MemorySystem& memory, std::shared_ptr<DebugContext> debug_context_);
    ~PicaCore();

    void BindRasterizer(VideoCore::RasterizerInterface* rasterizer);

    void SetInterruptHandler(Service::GSP::InterruptHandler& signal_interrupt);

    void ProcessCmdList(PAddr list, u32 size);

private:
    void InitializeRegs();

    void WriteInternalReg(u32 id, u32 value, u32 mask);

    void SubmitImmediate(u32 data);

    void DrawImmediate();

    void DrawArrays(bool is_indexed);

    void LoadVertices(bool is_indexed);

public:
    union Regs {
        static constexpr std::size_t NUM_REGS = 0x732;

        struct {
            u32 hardware_id;
            INSERT_PADDING_WORDS(0x3);
            MemoryFillConfig memory_fill_config[2];
            u32 vram_bank_control;
            u32 gpu_busy;
            INSERT_PADDING_WORDS(0x22);
            u32 backlight_control;
            INSERT_PADDING_WORDS(0xCF);
            FramebufferConfig framebuffer_config[2];
            INSERT_PADDING_WORDS(0x180);
            DisplayTransferConfig display_transfer_config;
            INSERT_PADDING_WORDS(0xF5);
            RegsInternal internal;
        };
        std::array<u32, NUM_REGS> reg_array;
    };
    static_assert(sizeof(Regs) == Regs::NUM_REGS * sizeof(u32));

    struct CommandList {
        PAddr addr;
        const u32* head;
        u32 current_index;
        u32 length;

        void Reset(PAddr addr, const u8* head, u32 size) {
            this->addr = addr;
            this->head = reinterpret_cast<const u32*>(head);
            this->length = size / sizeof(u32);
            current_index = 0;
        }

    private:
        friend class boost::serialization::access;
        template <class Archive>
        void serialize(Archive& ar, const u32 file_version);
    };

    struct ImmediateModeState {
        AttributeBuffer input_vertex{};
        u32 current_attribute{};
        bool reset_geometry_pipeline{true};
        PackedAttribute queue;

        void Reset() {
            current_attribute = 0;
            reset_geometry_pipeline = true;
            queue.Reset();
        }

    private:
        friend class boost::serialization::access;
        template <class Archive>
        void serialize(Archive& ar, const u32 file_version) {
            ar& input_vertex;
            ar& current_attribute;
            ar& reset_geometry_pipeline;
            ar& queue;
        }
    };

    struct ProcTex {
        union ValueEntry {
            u32 raw;

            // LUT value, encoded as 12-bit fixed point, with 12 fraction bits
            BitField<0, 12, u32> value; // 0.0.12 fixed point

            // Difference between two entry values. Used for efficient interpolation.
            // 0.0.12 fixed point with two's complement. The range is [-0.5, 0.5).
            // Note: the type of this is different from the one of lighting LUT
            BitField<12, 12, s32> difference;

            f32 ToFloat() const {
                return static_cast<f32>(value) / 4095.f;
            }

            f32 DiffToFloat() const {
                return static_cast<f32>(difference) / 4095.f;
            }
        };

        union ColorEntry {
            u32 raw;
            BitField<0, 8, u32> r;
            BitField<8, 8, u32> g;
            BitField<16, 8, u32> b;
            BitField<24, 8, u32> a;

            Common::Vec4<u8> ToVector() const {
                return {static_cast<u8>(r), static_cast<u8>(g), static_cast<u8>(b),
                        static_cast<u8>(a)};
            }
        };

        union ColorDifferenceEntry {
            u32 raw;
            BitField<0, 8, s32> r; // half of the difference between two ColorEntry
            BitField<8, 8, s32> g;
            BitField<16, 8, s32> b;
            BitField<24, 8, s32> a;

            Common::Vec4<s32> ToVector() const {
                return Common::Vec4<s32>{r, g, b, a} * 2;
            }
        };

        std::array<ValueEntry, 128> noise_table;
        std::array<ValueEntry, 128> color_map_table;
        std::array<ValueEntry, 128> alpha_map_table;
        std::array<ColorEntry, 256> color_table;
        std::array<ColorDifferenceEntry, 256> color_diff_table;

    private:
        friend class boost::serialization::access;
        template <class Archive>
        void serialize(Archive& ar, const u32 file_version) {
            ar& boost::serialization::make_binary_object(this, sizeof(ProcTex));
        }
    };

    struct Lighting {
        union LutEntry {
            // Used for raw access
            u32 raw;

            // LUT value, encoded as 12-bit fixed point, with 12 fraction bits
            BitField<0, 12, u32> value; // 0.0.12 fixed point

            // Used for efficient interpolation.
            BitField<12, 11, u32> difference; // 0.0.11 fixed point
            BitField<23, 1, u32> neg_difference;

            f32 ToFloat() const {
                return static_cast<f32>(value) / 4095.f;
            }

            f32 DiffToFloat() const {
                const f32 diff = static_cast<f32>(difference) / 2047.f;
                return neg_difference ? -diff : diff;
            }

            template <class Archive>
            void serialize(Archive& ar, const u32 file_version) {
                ar& raw;
            }
        };

        std::array<std::array<LutEntry, 256>, 24> luts;

    private:
        friend class boost::serialization::access;
        template <class Archive>
        void serialize(Archive& ar, const u32 file_version) {
            ar& boost::serialization::make_binary_object(this, sizeof(Lighting));
        }
    };

    struct Fog {
        union LutEntry {
            // Used for raw access
            u32 raw;

            BitField<0, 13, s32> difference; // 1.1.11 fixed point
            BitField<13, 11, u32> value;     // 0.0.11 fixed point

            f32 ToFloat() const {
                return static_cast<f32>(value) / 2047.0f;
            }

            f32 DiffToFloat() const {
                return static_cast<f32>(difference) / 2047.0f;
            }
        };

        std::array<LutEntry, 128> lut;

    private:
        friend class boost::serialization::access;
        template <class Archive>
        void serialize(Archive& ar, const u32 file_version) {
            ar& boost::serialization::make_binary_object(this, sizeof(Fog));
        }
    };

    RegsLcd regs_lcd{};
    Regs regs{};
    // TODO: Move these to a separate shader scheduler class
    GeometryShaderUnit gs_unit;
    ShaderSetup vs_setup;
    ShaderSetup gs_setup;
    ProcTex proctex{};
    Lighting lighting{};
    Fog fog{};
    AttributeBuffer input_default_attributes{};
    ImmediateModeState immediate{};

private:
    friend class boost::serialization::access;
    template <class Archive>
    void serialize(Archive& ar, const u32 file_version) {
        ar& regs_lcd;
        ar& regs.reg_array;
        ar& gs_unit;
        ar& vs_setup;
        ar& gs_setup;
        ar& proctex;
        ar& lighting;
        ar& fog;
        ar& input_default_attributes;
        ar& immediate;
        ar& geometry_pipeline;
        ar& primitive_assembler;
        ar& cmd_list;
    }

private:
    Memory::MemorySystem& memory;
    VideoCore::RasterizerInterface* rasterizer;
    std::shared_ptr<DebugContext> debug_context;
    Service::GSP::InterruptHandler signal_interrupt;
    GeometryPipeline geometry_pipeline;
    PrimitiveAssembler primitive_assembler;
    CommandList cmd_list;
    std::unique_ptr<ShaderEngine> shader_engine;
};

#define GPU_REG_INDEX(field_name) (offsetof(Pica::PicaCore::Regs, field_name) / sizeof(u32))

} // namespace Pica