// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later

#include <cstring>
#include <optional>
#include "common/assert.h"
#include "core/core.h"
#include "core/core_timing.h"
#include "video_core/dirty_flags.h"
#include "video_core/engines/draw_manager.h"
#include "video_core/engines/maxwell_3d.h"
#include "video_core/gpu.h"
#include "video_core/memory_manager.h"
#include "video_core/rasterizer_interface.h"
#include "video_core/textures/texture.h"

namespace Tegra::Engines {

using VideoCore::QueryType;

/// First register id that is actually a Macro call.
constexpr u32 MacroRegistersStart = 0xE00;

Maxwell3D::Maxwell3D(Core::System& system_, MemoryManager& memory_manager_)
    : draw_manager{std::make_unique<DrawManager>(this)}, system{system_},
      memory_manager{memory_manager_}, macro_engine{GetMacroEngine(*this)}, upload_state{
                                                                                memory_manager,
                                                                                regs.upload} {
    dirty.flags.flip();
    InitializeRegisterDefaults();
}

Maxwell3D::~Maxwell3D() = default;

void Maxwell3D::BindRasterizer(VideoCore::RasterizerInterface* rasterizer_) {
    rasterizer = rasterizer_;
    upload_state.BindRasterizer(rasterizer_);
}

void Maxwell3D::InitializeRegisterDefaults() {
    // Initializes registers to their default values - what games expect them to be at boot. This is
    // for certain registers that may not be explicitly set by games.

    // Reset all registers to zero
    std::memset(&regs, 0, sizeof(regs));

    // Depth range near/far is not always set, but is expected to be the default 0.0f, 1.0f. This is
    // needed for ARMS.
    for (auto& viewport : regs.viewports) {
        viewport.depth_range_near = 0.0f;
        viewport.depth_range_far = 1.0f;
    }
    for (auto& viewport : regs.viewport_transform) {
        viewport.swizzle.x.Assign(Regs::ViewportSwizzle::PositiveX);
        viewport.swizzle.y.Assign(Regs::ViewportSwizzle::PositiveY);
        viewport.swizzle.z.Assign(Regs::ViewportSwizzle::PositiveZ);
        viewport.swizzle.w.Assign(Regs::ViewportSwizzle::PositiveW);
    }

    // Doom and Bomberman seems to use the uninitialized registers and just enable blend
    // so initialize blend registers with sane values
    regs.blend.color_op = Regs::Blend::Equation::Add_D3D;
    regs.blend.color_source = Regs::Blend::Factor::One_D3D;
    regs.blend.color_dest = Regs::Blend::Factor::Zero_D3D;
    regs.blend.alpha_op = Regs::Blend::Equation::Add_D3D;
    regs.blend.alpha_source = Regs::Blend::Factor::One_D3D;
    regs.blend.alpha_dest = Regs::Blend::Factor::Zero_D3D;
    for (auto& blend : regs.blend_per_target) {
        blend.color_op = Regs::Blend::Equation::Add_D3D;
        blend.color_source = Regs::Blend::Factor::One_D3D;
        blend.color_dest = Regs::Blend::Factor::Zero_D3D;
        blend.alpha_op = Regs::Blend::Equation::Add_D3D;
        blend.alpha_source = Regs::Blend::Factor::One_D3D;
        blend.alpha_dest = Regs::Blend::Factor::Zero_D3D;
    }
    regs.stencil_front_op.fail = Regs::StencilOp::Op::Keep_D3D;
    regs.stencil_front_op.zfail = Regs::StencilOp::Op::Keep_D3D;
    regs.stencil_front_op.zpass = Regs::StencilOp::Op::Keep_D3D;
    regs.stencil_front_op.func = Regs::ComparisonOp::Always_GL;
    regs.stencil_front_func_mask = 0xFFFFFFFF;
    regs.stencil_front_mask = 0xFFFFFFFF;
    regs.stencil_two_side_enable = 1;
    regs.stencil_back_op.fail = Regs::StencilOp::Op::Keep_D3D;
    regs.stencil_back_op.zfail = Regs::StencilOp::Op::Keep_D3D;
    regs.stencil_back_op.zpass = Regs::StencilOp::Op::Keep_D3D;
    regs.stencil_back_op.func = Regs::ComparisonOp::Always_GL;
    regs.stencil_back_func_mask = 0xFFFFFFFF;
    regs.stencil_back_mask = 0xFFFFFFFF;

    regs.depth_test_func = Regs::ComparisonOp::Always_GL;
    regs.gl_front_face = Regs::FrontFace::CounterClockWise;
    regs.gl_cull_face = Regs::CullFace::Back;

    // TODO(Rodrigo): Most games do not set a point size. I think this is a case of a
    // register carrying a default value. Assume it's OpenGL's default (1).
    regs.point_size = 1.0f;

    // TODO(bunnei): Some games do not initialize the color masks (e.g. Sonic Mania). Assuming a
    // default of enabled fixes rendering here.
    for (auto& color_mask : regs.color_mask) {
        color_mask.R.Assign(1);
        color_mask.G.Assign(1);
        color_mask.B.Assign(1);
        color_mask.A.Assign(1);
    }

    for (auto& format : regs.vertex_attrib_format) {
        format.constant.Assign(1);
    }

    // NVN games expect these values to be enabled at boot
    regs.rasterize_enable = 1;
    regs.color_target_mrt_enable = 1;
    regs.framebuffer_srgb = 1;
    regs.line_width_aliased = 1.0f;
    regs.line_width_smooth = 1.0f;
    regs.gl_front_face = Maxwell3D::Regs::FrontFace::ClockWise;
    regs.polygon_mode_back = Maxwell3D::Regs::PolygonMode::Fill;
    regs.polygon_mode_front = Maxwell3D::Regs::PolygonMode::Fill;

    shadow_state = regs;
}

void Maxwell3D::ProcessMacro(u32 method, const u32* base_start, u32 amount, bool is_last_call) {
    if (executing_macro == 0) {
        // A macro call must begin by writing the macro method's register, not its argument.
        ASSERT_MSG((method % 2) == 0,
                   "Can't start macro execution by writing to the ARGS register");
        executing_macro = method;
    }

    macro_params.insert(macro_params.end(), base_start, base_start + amount);
    for (size_t i = 0; i < amount; i++) {
        macro_addresses.push_back(current_dma_segment + i * sizeof(u32));
    }
    macro_segments.emplace_back(current_dma_segment, amount);

    // Call the macro when there are no more parameters in the command buffer
    if (is_last_call) {
        CallMacroMethod(executing_macro, macro_params);
        macro_params.clear();
        macro_addresses.clear();
        macro_segments.clear();
    }
}

void Maxwell3D::RefreshParameters() {
    size_t current_index = 0;
    for (auto& segment : macro_segments) {
        if (segment.first == 0) {
            current_index += segment.second;
            continue;
        }
        memory_manager.ReadBlock(segment.first, &macro_params[current_index],
                                 sizeof(u32) * segment.second);
        current_index += segment.second;
    }
}

u32 Maxwell3D::GetMaxCurrentVertices() {
    u32 num_vertices = 0;
    for (size_t index = 0; index < Regs::NumVertexArrays; ++index) {
        const auto& array = regs.vertex_streams[index];
        if (array.enable == 0) {
            continue;
        }
        const auto& attribute = regs.vertex_attrib_format[index];
        if (attribute.constant) {
            num_vertices = std::max(num_vertices, 1U);
            continue;
        }
        const auto& limit = regs.vertex_stream_limits[index];
        const GPUVAddr gpu_addr_begin = array.Address();
        const GPUVAddr gpu_addr_end = limit.Address() + 1;
        const u32 address_size = static_cast<u32>(gpu_addr_end - gpu_addr_begin);
        num_vertices = std::max(
            num_vertices, address_size / std::max(attribute.SizeInBytes(), array.stride.Value()));
    }
    return num_vertices;
}

u32 Maxwell3D::ProcessShadowRam(u32 method, u32 argument) {
    // Keep track of the register value in shadow_state when requested.
    const auto control = shadow_state.shadow_ram_control;
    if (control == Regs::ShadowRamControl::Track ||
        control == Regs::ShadowRamControl::TrackWithFilter) {
        shadow_state.reg_array[method] = argument;
        return argument;
    }
    if (control == Regs::ShadowRamControl::Replay) {
        return shadow_state.reg_array[method];
    }
    return argument;
}

void Maxwell3D::ProcessDirtyRegisters(u32 method, u32 argument) {
    if (regs.reg_array[method] == argument) {
        return;
    }
    regs.reg_array[method] = argument;

    for (const auto& table : dirty.tables) {
        dirty.flags[table[method]] = true;
    }
}

void Maxwell3D::ProcessMethodCall(u32 method, u32 argument, u32 nonshadow_argument,
                                  bool is_last_call) {
    switch (method) {
    case MAXWELL3D_REG_INDEX(wait_for_idle):
        return rasterizer->WaitForIdle();
    case MAXWELL3D_REG_INDEX(shadow_ram_control):
        shadow_state.shadow_ram_control = static_cast<Regs::ShadowRamControl>(nonshadow_argument);
        return;
    case MAXWELL3D_REG_INDEX(load_mme.instruction_ptr):
        return macro_engine->ClearCode(regs.load_mme.instruction_ptr);
    case MAXWELL3D_REG_INDEX(load_mme.instruction):
        return macro_engine->AddCode(regs.load_mme.instruction_ptr, argument);
    case MAXWELL3D_REG_INDEX(load_mme.start_address):
        return ProcessMacroBind(argument);
    case MAXWELL3D_REG_INDEX(falcon[4]):
        return ProcessFirmwareCall4();
    case MAXWELL3D_REG_INDEX(const_buffer.buffer):
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 1:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 2:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 3:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 4:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 5:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 6:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 7:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 8:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 9:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 10:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 11:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 12:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 13:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 14:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 15:
        return ProcessCBData(argument);
    case MAXWELL3D_REG_INDEX(bind_groups[0].raw_config):
        return ProcessCBBind(0);
    case MAXWELL3D_REG_INDEX(bind_groups[1].raw_config):
        return ProcessCBBind(1);
    case MAXWELL3D_REG_INDEX(bind_groups[2].raw_config):
        return ProcessCBBind(2);
    case MAXWELL3D_REG_INDEX(bind_groups[3].raw_config):
        return ProcessCBBind(3);
    case MAXWELL3D_REG_INDEX(bind_groups[4].raw_config):
        return ProcessCBBind(4);
    case MAXWELL3D_REG_INDEX(report_semaphore.query):
        return ProcessQueryGet();
    case MAXWELL3D_REG_INDEX(render_enable.mode):
        return ProcessQueryCondition();
    case MAXWELL3D_REG_INDEX(clear_report_value):
        return ProcessCounterReset();
    case MAXWELL3D_REG_INDEX(sync_info):
        return ProcessSyncPoint();
    case MAXWELL3D_REG_INDEX(launch_dma):
        return upload_state.ProcessExec(regs.launch_dma.memory_layout.Value() ==
                                        Regs::LaunchDMA::Layout::Pitch);
    case MAXWELL3D_REG_INDEX(inline_data):
        upload_state.ProcessData(argument, is_last_call);
        return;
    case MAXWELL3D_REG_INDEX(fragment_barrier):
        return rasterizer->FragmentBarrier();
    case MAXWELL3D_REG_INDEX(tiled_cache_barrier):
        return rasterizer->TiledCacheBarrier();
    default:
        draw_manager->ProcessMethodCall(method, argument);
        break;
    }
}

void Maxwell3D::CallMacroMethod(u32 method, const std::vector<u32>& parameters) {
    // Reset the current macro.
    executing_macro = 0;

    // Lookup the macro offset
    const u32 entry =
        ((method - MacroRegistersStart) >> 1) % static_cast<u32>(macro_positions.size());

    // Execute the current macro.
    macro_engine->Execute(macro_positions[entry], parameters);

    draw_manager->DrawDeferred();
}

void Maxwell3D::CallMethod(u32 method, u32 method_argument, bool is_last_call) {
    // It is an error to write to a register other than the current macro's ARG register before
    // it has finished execution.
    if (executing_macro != 0) {
        ASSERT(method == executing_macro + 1);
    }

    // Methods after 0xE00 are special, they're actually triggers for some microcode that was
    // uploaded to the GPU during initialization.
    if (method >= MacroRegistersStart) {
        ProcessMacro(method, &method_argument, 1, is_last_call);
        return;
    }

    ASSERT_MSG(method < Regs::NUM_REGS,
               "Invalid Maxwell3D register, increase the size of the Regs structure");

    const u32 argument = ProcessShadowRam(method, method_argument);
    ProcessDirtyRegisters(method, argument);

    ProcessMethodCall(method, argument, method_argument, is_last_call);
}

void Maxwell3D::CallMultiMethod(u32 method, const u32* base_start, u32 amount,
                                u32 methods_pending) {
    // Methods after 0xE00 are special, they're actually triggers for some microcode that was
    // uploaded to the GPU during initialization.
    if (method >= MacroRegistersStart) {
        ProcessMacro(method, base_start, amount, amount == methods_pending);
        return;
    }
    switch (method) {
    case MAXWELL3D_REG_INDEX(const_buffer.buffer):
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 1:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 2:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 3:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 4:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 5:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 6:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 7:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 8:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 9:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 10:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 11:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 12:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 13:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 14:
    case MAXWELL3D_REG_INDEX(const_buffer.buffer) + 15:
        ProcessCBMultiData(base_start, amount);
        break;
    case MAXWELL3D_REG_INDEX(inline_data):
        upload_state.ProcessData(base_start, amount);
        return;
    default:
        for (u32 i = 0; i < amount; i++) {
            CallMethod(method, base_start[i], methods_pending - i <= 1);
        }
        break;
    }
}

void Maxwell3D::ProcessMacroUpload(u32 data) {
    macro_engine->AddCode(regs.load_mme.instruction_ptr++, data);
}

void Maxwell3D::ProcessMacroBind(u32 data) {
    macro_positions[regs.load_mme.start_address_ptr++] = data;
}

void Maxwell3D::ProcessFirmwareCall4() {
    LOG_WARNING(HW_GPU, "(STUBBED) called");

    // Firmware call 4 is a blob that changes some registers depending on its parameters.
    // These registers don't affect emulation and so are stubbed by setting 0xd00 to 1.
    regs.shadow_scratch[0] = 1;
}

void Maxwell3D::StampQueryResult(u64 payload, bool long_query) {
    const GPUVAddr sequence_address{regs.report_semaphore.Address()};
    if (long_query) {
        memory_manager.Write<u64>(sequence_address + sizeof(u64), system.GPU().GetTicks());
        memory_manager.Write<u64>(sequence_address, payload);
    } else {
        memory_manager.Write<u32>(sequence_address, static_cast<u32>(payload));
    }
}

void Maxwell3D::ProcessQueryGet() {
    // TODO(Subv): Support the other query units.
    if (regs.report_semaphore.query.location != Regs::ReportSemaphore::Location::All) {
        LOG_DEBUG(HW_GPU, "Locations other than ALL are unimplemented");
    }

    switch (regs.report_semaphore.query.operation) {
    case Regs::ReportSemaphore::Operation::Release:
        if (regs.report_semaphore.query.short_query != 0) {
            const GPUVAddr sequence_address{regs.report_semaphore.Address()};
            const u32 payload = regs.report_semaphore.payload;
            std::function<void()> operation([this, sequence_address, payload] {
                memory_manager.Write<u32>(sequence_address, payload);
            });
            rasterizer->SignalFence(std::move(operation));
        } else {
            struct LongQueryResult {
                u64_le value;
                u64_le timestamp;
            };
            const GPUVAddr sequence_address{regs.report_semaphore.Address()};
            const u32 payload = regs.report_semaphore.payload;
            [this, sequence_address, payload] {
                memory_manager.Write<u64>(sequence_address + sizeof(u64), system.GPU().GetTicks());
                memory_manager.Write<u64>(sequence_address, payload);
            }();
        }
        break;
    case Regs::ReportSemaphore::Operation::Acquire:
        // TODO(Blinkhawk): Under this operation, the GPU waits for the CPU to write a value that
        // matches the current payload.
        UNIMPLEMENTED_MSG("Unimplemented query operation ACQUIRE");
        break;
    case Regs::ReportSemaphore::Operation::ReportOnly:
        if (const std::optional<u64> result = GetQueryResult()) {
            // If the query returns an empty optional it means it's cached and deferred.
            // In this case we have a non-empty result, so we stamp it immediately.
            StampQueryResult(*result, regs.report_semaphore.query.short_query == 0);
        }
        break;
    case Regs::ReportSemaphore::Operation::Trap:
        UNIMPLEMENTED_MSG("Unimplemented query operation TRAP");
        break;
    default:
        UNIMPLEMENTED_MSG("Unknown query operation");
        break;
    }
}

void Maxwell3D::ProcessQueryCondition() {
    const GPUVAddr condition_address{regs.render_enable.Address()};
    switch (regs.render_enable_override) {
    case Regs::RenderEnable::Override::AlwaysRender:
        execute_on = true;
        break;
    case Regs::RenderEnable::Override::NeverRender:
        execute_on = false;
        break;
    case Regs::RenderEnable::Override::UseRenderEnable:
        switch (regs.render_enable.mode) {
        case Regs::RenderEnable::Mode::True: {
            execute_on = true;
            break;
        }
        case Regs::RenderEnable::Mode::False: {
            execute_on = false;
            break;
        }
        case Regs::RenderEnable::Mode::Conditional: {
            Regs::ReportSemaphore::Compare cmp;
            memory_manager.ReadBlock(condition_address, &cmp, sizeof(cmp));
            execute_on = cmp.initial_sequence != 0U && cmp.initial_mode != 0U;
            break;
        }
        case Regs::RenderEnable::Mode::IfEqual: {
            Regs::ReportSemaphore::Compare cmp;
            memory_manager.ReadBlock(condition_address, &cmp, sizeof(cmp));
            execute_on = cmp.initial_sequence == cmp.current_sequence &&
                         cmp.initial_mode == cmp.current_mode;
            break;
        }
        case Regs::RenderEnable::Mode::IfNotEqual: {
            Regs::ReportSemaphore::Compare cmp;
            memory_manager.ReadBlock(condition_address, &cmp, sizeof(cmp));
            execute_on = cmp.initial_sequence != cmp.current_sequence ||
                         cmp.initial_mode != cmp.current_mode;
            break;
        }
        default: {
            UNIMPLEMENTED_MSG("Uninplemented Condition Mode!");
            execute_on = true;
            break;
        }
        }
        break;
    }
}

void Maxwell3D::ProcessCounterReset() {
    switch (regs.clear_report_value) {
    case Regs::ClearReport::ZPassPixelCount:
        rasterizer->ResetCounter(QueryType::SamplesPassed);
        break;
    default:
        LOG_DEBUG(Render_OpenGL, "Unimplemented counter reset={}", regs.clear_report_value);
        break;
    }
}

void Maxwell3D::ProcessSyncPoint() {
    const u32 sync_point = regs.sync_info.sync_point.Value();
    [[maybe_unused]] const u32 cache_flush = regs.sync_info.clean_l2.Value();
    rasterizer->SignalSyncPoint(sync_point);
}

std::optional<u64> Maxwell3D::GetQueryResult() {
    switch (regs.report_semaphore.query.report) {
    case Regs::ReportSemaphore::Report::Payload:
        return regs.report_semaphore.payload;
    case Regs::ReportSemaphore::Report::ZPassPixelCount64:
        // Deferred.
        rasterizer->Query(regs.report_semaphore.Address(), QueryType::SamplesPassed,
                          system.GPU().GetTicks());
        return std::nullopt;
    default:
        LOG_DEBUG(HW_GPU, "Unimplemented query report type {}",
                  regs.report_semaphore.query.report.Value());
        return 1;
    }
}

void Maxwell3D::ProcessCBBind(size_t stage_index) {
    // Bind the buffer currently in CB_ADDRESS to the specified index in the desired shader stage.
    const auto& bind_data = regs.bind_groups[stage_index];
    auto& buffer = state.shader_stages[stage_index].const_buffers[bind_data.shader_slot];
    buffer.enabled = bind_data.valid.Value() != 0;
    buffer.address = regs.const_buffer.Address();
    buffer.size = regs.const_buffer.size;

    const bool is_enabled = bind_data.valid.Value() != 0;
    if (!is_enabled) {
        rasterizer->DisableGraphicsUniformBuffer(stage_index, bind_data.shader_slot);
        return;
    }
    const GPUVAddr gpu_addr = regs.const_buffer.Address();
    const u32 size = regs.const_buffer.size;
    rasterizer->BindGraphicsUniformBuffer(stage_index, bind_data.shader_slot, gpu_addr, size);
}

void Maxwell3D::ProcessCBMultiData(const u32* start_base, u32 amount) {
    // Write the input value to the current const buffer at the current position.
    const GPUVAddr buffer_address = regs.const_buffer.Address();
    ASSERT(buffer_address != 0);

    // Don't allow writing past the end of the buffer.
    ASSERT(regs.const_buffer.offset <= regs.const_buffer.size);

    const GPUVAddr address{buffer_address + regs.const_buffer.offset};
    const size_t copy_size = amount * sizeof(u32);
    memory_manager.WriteBlock(address, start_base, copy_size);

    // Increment the current buffer position.
    regs.const_buffer.offset += static_cast<u32>(copy_size);
}

void Maxwell3D::ProcessCBData(u32 value) {
    ProcessCBMultiData(&value, 1);
}

Texture::TICEntry Maxwell3D::GetTICEntry(u32 tic_index) const {
    const GPUVAddr tic_address_gpu{regs.tex_header.Address() +
                                   tic_index * sizeof(Texture::TICEntry)};

    Texture::TICEntry tic_entry;
    memory_manager.ReadBlockUnsafe(tic_address_gpu, &tic_entry, sizeof(Texture::TICEntry));

    return tic_entry;
}

Texture::TSCEntry Maxwell3D::GetTSCEntry(u32 tsc_index) const {
    const GPUVAddr tsc_address_gpu{regs.tex_sampler.Address() +
                                   tsc_index * sizeof(Texture::TSCEntry)};

    Texture::TSCEntry tsc_entry;
    memory_manager.ReadBlockUnsafe(tsc_address_gpu, &tsc_entry, sizeof(Texture::TSCEntry));
    return tsc_entry;
}

u32 Maxwell3D::GetRegisterValue(u32 method) const {
    ASSERT_MSG(method < Regs::NUM_REGS, "Invalid Maxwell3D register");
    return regs.reg_array[method];
}

} // namespace Tegra::Engines