// Copyright 2024 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#include <algorithm>
#include <cstring>
#include <memory>
#include <vector>
#include <fmt/format.h>
#include "common/literals.h"
#include "common/logging/log.h"
#include "common/settings.h"
#include "common/string_util.h"
#include "common/swap.h"
#include "core/core.h"
#include "core/file_sys/ncch_container.h"
#include "core/file_sys/romfs_reader.h"
#include "core/file_sys/secure_value_backend_artic.h"
#include "core/file_sys/title_metadata.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/resource_limit.h"
#include "core/hle/service/am/am.h"
#include "core/hle/service/am/am_app.h"
#include "core/hle/service/am/am_net.h"
#include "core/hle/service/cfg/cfg.h"
#include "core/hle/service/cfg/cfg_u.h"
#include "core/hle/service/fs/archive.h"
#include "core/hle/service/fs/fs_user.h"
#include "core/hle/service/hid/hid_user.h"
#include "core/loader/artic.h"
#include "core/loader/smdh.h"
#include "core/memory.h"
#include "core/system_titles.h"
#include "network/network.h"

namespace Loader {

using namespace Common::Literals;

Apploader_Artic::~Apploader_Artic() {
    // TODO(PabloMK7) Find memory leak that prevents the romfs readers being destroyed
    // when emulation stops. Looks like the mem leak comes from IVFCFile objects
    // not being destroyed...
    if (main_romfs_reader) {
        static_cast<FileSys::ArticRomFSReader*>(main_romfs_reader.get())->ClearCache();
        static_cast<FileSys::ArticRomFSReader*>(main_romfs_reader.get())->CloseFile();
        main_romfs_reader.reset();
    }
    if (update_romfs_reader) {
        static_cast<FileSys::ArticRomFSReader*>(update_romfs_reader.get())->ClearCache();
        static_cast<FileSys::ArticRomFSReader*>(update_romfs_reader.get())->CloseFile();
        update_romfs_reader.reset();
    }
    client->Stop();
}

FileType Apploader_Artic::IdentifyType(FileUtil::IOFile& file) {
    return FileType::ARTIC;
}

std::pair<std::optional<u32>, ResultStatus> Apploader_Artic::LoadCoreVersion() {
    if (!is_loaded) {
        bool success = LoadExheader();
        if (!success) {
            return std::make_pair(std::nullopt, ResultStatus::ErrorArtic);
        }
    }

    // Provide the core version from the exheader.
    auto& ncch_caps = program_exheader.arm11_system_local_caps;
    return std::make_pair(ncch_caps.core_version, ResultStatus::Success);
}

std::pair<std::optional<Kernel::MemoryMode>, ResultStatus> Apploader_Artic::LoadKernelMemoryMode() {
    if (!is_loaded) {
        bool success = LoadExheader();
        if (!success) {
            return std::make_pair(std::nullopt, ResultStatus::ErrorArtic);
        }
    }

    if (memory_mode_override.has_value()) {
        return std::make_pair(memory_mode_override, ResultStatus::Success);
    }

    // Provide the memory mode from the exheader.
    auto& ncch_caps = program_exheader.arm11_system_local_caps;
    auto mode = static_cast<Kernel::MemoryMode>(ncch_caps.system_mode.Value());
    return std::make_pair(mode, ResultStatus::Success);
}

std::pair<std::optional<Kernel::New3dsHwCapabilities>, ResultStatus>
Apploader_Artic::LoadNew3dsHwCapabilities() {
    if (!is_loaded) {
        bool success = LoadExheader();
        if (!success) {
            return std::make_pair(std::nullopt, ResultStatus::ErrorArtic);
        }
    }

    // Provide the capabilities from the exheader.
    auto& ncch_caps = program_exheader.arm11_system_local_caps;
    auto caps = Kernel::New3dsHwCapabilities{
        ncch_caps.enable_l2_cache != 0,
        ncch_caps.enable_804MHz_cpu != 0,
        static_cast<Kernel::New3dsMemoryMode>(ncch_caps.n3ds_mode),
    };
    return std::make_pair(std::move(caps), ResultStatus::Success);
}

ResultStatus Apploader_Artic::LoadExec(std::shared_ptr<Kernel::Process>& process) {
    using Kernel::CodeSet;

    if (!is_loaded)
        return ResultStatus::ErrorNotLoaded;

    std::vector<u8> code;
    u64_le program_id;
    if (ResultStatus::Success == ReadCode(code) &&
        ResultStatus::Success == ReadProgramId(program_id)) {

        std::string process_name = Common::StringFromFixedZeroTerminatedBuffer(
            (const char*)program_exheader.codeset_info.name, 8);

        std::shared_ptr<CodeSet> codeset = system.Kernel().CreateCodeSet(process_name, program_id);

        codeset->CodeSegment().offset = 0;
        codeset->CodeSegment().addr = program_exheader.codeset_info.text.address;
        codeset->CodeSegment().size =
            program_exheader.codeset_info.text.num_max_pages * Memory::CITRA_PAGE_SIZE;

        codeset->RODataSegment().offset =
            codeset->CodeSegment().offset + codeset->CodeSegment().size;
        codeset->RODataSegment().addr = program_exheader.codeset_info.ro.address;
        codeset->RODataSegment().size =
            program_exheader.codeset_info.ro.num_max_pages * Memory::CITRA_PAGE_SIZE;

        // TODO(yuriks): Not sure if the bss size is added to the page-aligned .data size or just
        //               to the regular size. Playing it safe for now.
        u32 bss_page_size = (program_exheader.codeset_info.bss_size + 0xFFF) & ~0xFFF;
        code.resize(code.size() + bss_page_size, 0);

        codeset->DataSegment().offset =
            codeset->RODataSegment().offset + codeset->RODataSegment().size;
        codeset->DataSegment().addr = program_exheader.codeset_info.data.address;
        codeset->DataSegment().size =
            program_exheader.codeset_info.data.num_max_pages * Memory::CITRA_PAGE_SIZE +
            bss_page_size;

        // Apply patches now that the entire codeset (including .bss) has been allocated
        // const ResultStatus patch_result = overlay_ncch->ApplyCodePatch(code);
        // if (patch_result != ResultStatus::Success && patch_result != ResultStatus::ErrorNotUsed)
        //    return patch_result;

        codeset->entrypoint = codeset->CodeSegment().addr;
        codeset->memory = std::move(code);

        process = system.Kernel().CreateProcess(std::move(codeset));

        // Attach a resource limit to the process based on the resource limit category
        const auto category = static_cast<Kernel::ResourceLimitCategory>(
            program_exheader.arm11_system_local_caps.resource_limit_category);
        process->resource_limit = system.Kernel().ResourceLimit().GetForCategory(category);

        // When running N3DS-unaware titles pm will lie about the amount of memory available.
        // This means RESLIMIT_COMMIT = APPMEMALLOC doesn't correspond to the actual size of
        // APPLICATION. See:
        // https://github.com/LumaTeam/Luma3DS/blob/e2778a45/sysmodules/pm/source/launch.c#L237
        auto& ncch_caps = program_exheader.arm11_system_local_caps;
        const auto o3ds_mode = *LoadKernelMemoryMode().first;
        const auto n3ds_mode = static_cast<Kernel::New3dsMemoryMode>(ncch_caps.n3ds_mode);
        const bool is_new_3ds = Settings::values.is_new_3ds.GetValue();
        if (is_new_3ds && n3ds_mode == Kernel::New3dsMemoryMode::Legacy &&
            category == Kernel::ResourceLimitCategory::Application) {
            u64 new_limit = 0;
            switch (o3ds_mode) {
            case Kernel::MemoryMode::Prod:
                new_limit = 64_MiB;
                break;
            case Kernel::MemoryMode::Dev1:
                new_limit = 96_MiB;
                break;
            case Kernel::MemoryMode::Dev2:
                new_limit = 80_MiB;
                break;
            default:
                break;
            }
            process->resource_limit->SetLimitValue(Kernel::ResourceLimitType::Commit,
                                                   static_cast<s32>(new_limit));
        }

        // Set the default CPU core for this process
        process->ideal_processor = program_exheader.arm11_system_local_caps.ideal_processor;

        // Copy data while converting endianness
        using KernelCaps = std::array<u32, ExHeader_ARM11_KernelCaps::NUM_DESCRIPTORS>;
        KernelCaps kernel_caps;
        std::copy_n(program_exheader.arm11_kernel_caps.descriptors, kernel_caps.size(),
                    begin(kernel_caps));
        process->ParseKernelCaps(kernel_caps.data(), kernel_caps.size());

        s32 priority = program_exheader.arm11_system_local_caps.priority;
        u32 stack_size = program_exheader.codeset_info.stack_size;

        // On real HW this is done with FS:Reg, but we can be lazy
        auto fs_user = system.ServiceManager().GetService<Service::FS::FS_USER>("fs:USER");
        fs_user->RegisterProgramInfo(process->process_id, process->codeset->program_id,
                                     "articbase://");

        Service::FS::FS_USER::ProductInfo product_info{};
        if (LoadProductInfo(product_info) != ResultStatus::Success) {
            return ResultStatus::ErrorArtic;
        }
        fs_user->RegisterProductInfo(process->process_id, product_info);

        process->Run(priority, stack_size);
        return ResultStatus::Success;
    }
    return ResultStatus::ErrorArtic;
}

void Apploader_Artic::ParseRegionLockoutInfo(u64 program_id) {
    if (Settings::values.region_value.GetValue() != Settings::REGION_VALUE_AUTO_SELECT) {
        return;
    }

    preferred_regions.clear();

    std::vector<u8> smdh_buffer;
    if (ReadIcon(smdh_buffer) == ResultStatus::Success && smdh_buffer.size() >= sizeof(SMDH)) {
        SMDH smdh;
        std::memcpy(&smdh, smdh_buffer.data(), sizeof(SMDH));
        u32 region_lockout = smdh.region_lockout;
        constexpr u32 REGION_COUNT = 7;
        for (u32 region = 0; region < REGION_COUNT; ++region) {
            if (region_lockout & 1) {
                preferred_regions.push_back(region);
            }
            region_lockout >>= 1;
        }
    } else {
        const auto region = Core::GetSystemTitleRegion(program_id);
        if (region.has_value()) {
            preferred_regions.push_back(region.value());
        }
    }
}

bool Apploader_Artic::LoadExheader() {
    if (program_exheader_loaded)
        return true;

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return false;

    auto req = client->NewRequest("Process_GetExheader");
    auto resp = client->Send(req);
    if (!resp.has_value())
        return false;

    auto exheader_buf = resp->GetResponseBuffer(0);
    if (!exheader_buf.has_value())
        return false;

    if (exheader_buf->second != sizeof(ExHeader_Header) - sizeof(ExHeader_Header::access_desc))
        return false;

    u8* prg_exh = reinterpret_cast<u8*>(&program_exheader);
    memcpy(prg_exh, exheader_buf->first,
           sizeof(ExHeader_Header) - sizeof(ExHeader_Header::access_desc));
    memcpy(prg_exh + offsetof(ExHeader_Header, access_desc.arm11_system_local_caps),
           reinterpret_cast<u8*>(exheader_buf->first) +
               offsetof(ExHeader_Header, arm11_system_local_caps),
           offsetof(ExHeader_Header, access_desc) -
               offsetof(ExHeader_Header, arm11_system_local_caps));
    program_exheader_loaded = true;
    return true;
}

ResultStatus Apploader_Artic::LoadProductInfo(Service::FS::FS_USER::ProductInfo& out_product_info) {
    if (cached_product_info.has_value()) {
        out_product_info = *cached_product_info;
        return ResultStatus::Success;
    }

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return ResultStatus::ErrorArtic;

    auto req = client->NewRequest("Process_GetProductInfo");
    auto resp = client->Send(req);
    if (!resp.has_value())
        return ResultStatus::ErrorArtic;

    auto pinfo_buf = resp->GetResponseBuffer(0);
    if (!pinfo_buf.has_value() || pinfo_buf->second != sizeof(Service::FS::FS_USER::ProductInfo))
        return ResultStatus::ErrorArtic;

    out_product_info = *reinterpret_cast<Service::FS::FS_USER::ProductInfo*>(pinfo_buf->first);
    cached_product_info = out_product_info;

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::Load(std::shared_ptr<Kernel::Process>& process) {
    u64_le ncch_program_id;

    if (is_loaded)
        return ResultStatus::ErrorAlreadyLoaded;

    ResultStatus result = ReadProgramId(ncch_program_id);
    if (result != ResultStatus::Success) {
        return result;
    }

    std::string program_id{fmt::format("{:016X}", ncch_program_id)};

    LOG_INFO(Loader, "Program ID: {}", program_id);

    if (auto room_member = Network::GetRoomMember().lock()) {
        Network::GameInfo game_info;
        ReadTitle(game_info.name);
        game_info.id = ncch_program_id;
        room_member->SendGameInfo(game_info);
    }

    is_loaded = true; // Set state to loaded

    result = LoadExec(process); // Load the executable into memory for booting
    if (ResultStatus::Success != result)
        return result;

    system.ArchiveManager().RegisterSelfNCCH(*this);
    system.ArchiveManager().RegisterArticSaveDataSource(client);
    system.ArchiveManager().RegisterArticExtData(client);
    system.ArchiveManager().RegisterArticNCCH(client);
    system.ArchiveManager().RegisterArticSystemSaveData(client);

    auto fs_user = system.ServiceManager().GetService<Service::FS::FS_USER>("fs:USER");
    if (fs_user.get()) {
        fs_user->RegisterSecureValueBackend(
            std::make_shared<FileSys::ArticSecureValueBackend>(client));
    }

    auto cfg = system.ServiceManager().GetService<Service::CFG::CFG_U>("cfg:u");
    if (cfg.get()) {
        cfg->UseArticClient(client);
    }

    auto amnet = system.ServiceManager().GetService<Service::AM::AM_NET>("am:net");
    if (amnet.get()) {
        amnet->UseArticClient(client);
    }

    auto amapp = system.ServiceManager().GetService<Service::AM::AM_APP>("am:app");
    if (amapp.get()) {
        amapp->UseArticClient(client);
    }

    if (Settings::values.use_artic_base_controller.GetValue()) {
        auto hid_user = system.ServiceManager().GetService<Service::HID::User>("hid:USER");
        if (hid_user.get()) {
            hid_user->GetModule()->UseArticClient(client);
        }
    }

    ParseRegionLockoutInfo(ncch_program_id);

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::IsExecutable(bool& out_executable) {
    out_executable = true;
    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadCode(std::vector<u8>& buffer) {
    // Code is only read once, there is no need to cache it.

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return ResultStatus::ErrorArtic;

    size_t code_size = program_exheader.codeset_info.text.num_max_pages * Memory::CITRA_PAGE_SIZE;
    code_size += program_exheader.codeset_info.ro.num_max_pages * Memory::CITRA_PAGE_SIZE;
    code_size += program_exheader.codeset_info.data.num_max_pages * Memory::CITRA_PAGE_SIZE;

    size_t read_amount = 0;
    buffer.clear();

    while (read_amount != code_size) {
        size_t to_read =
            std::min<size_t>(client->GetServerRequestMaxSize() - 0x100, code_size - read_amount);

        auto req = client->NewRequest("Process_ReadCode");
        req.AddParameterS32(static_cast<s32>(read_amount));
        req.AddParameterS32(static_cast<s32>(to_read));
        auto resp = client->Send(req);
        if (!resp.has_value() || !resp->Succeeded() || resp->GetMethodResult() != 0)
            return ResultStatus::ErrorArtic;

        auto code_buff = resp->GetResponseBuffer(0);
        if (!code_buff.has_value() || code_buff->second != to_read)
            return ResultStatus::ErrorArtic;

        buffer.resize(read_amount + to_read);
        memcpy(buffer.data() + read_amount, code_buff->first, to_read);
        read_amount += to_read;
    }

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadIcon(std::vector<u8>& buffer) {
    if (!cached_icon.empty()) {
        buffer = cached_icon;
        return ResultStatus::Success;
    }

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return ResultStatus::ErrorArtic;

    auto req = client->NewRequest("Process_ReadIcon");
    auto resp = client->Send(req);
    if (!resp.has_value() || !resp->Succeeded() || resp->GetMethodResult() != 0)
        return ResultStatus::ErrorArtic;

    auto icon_buf = resp->GetResponseBuffer(0);
    if (!icon_buf.has_value())
        return ResultStatus::ErrorArtic;

    cached_icon.resize(icon_buf->second);
    memcpy(cached_icon.data(), icon_buf->first, icon_buf->second);
    buffer = cached_icon;

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadBanner(std::vector<u8>& buffer) {
    if (!cached_banner.empty()) {
        buffer = cached_banner;
        return ResultStatus::Success;
    }

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return ResultStatus::ErrorArtic;

    auto req = client->NewRequest("Process_ReadBanner");
    auto resp = client->Send(req);
    if (!resp.has_value() || !resp->Succeeded() || resp->GetMethodResult() != 0)
        return ResultStatus::ErrorArtic;

    auto banner_buf = resp->GetResponseBuffer(0);
    if (!banner_buf.has_value())
        return ResultStatus::ErrorArtic;

    cached_banner.resize(banner_buf->second);
    memcpy(cached_banner.data(), banner_buf->first, banner_buf->second);
    buffer = cached_banner;

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadLogo(std::vector<u8>& buffer) {
    if (!cached_logo.empty()) {
        buffer = cached_logo;
        return ResultStatus::Success;
    }

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return ResultStatus::ErrorArtic;

    auto req = client->NewRequest("Process_ReadLogo");
    auto resp = client->Send(req);
    if (!resp.has_value() || !resp->Succeeded() || resp->GetMethodResult() != 0)
        return ResultStatus::ErrorArtic;

    auto logo_buf = resp->GetResponseBuffer(0);
    if (!logo_buf.has_value())
        return ResultStatus::ErrorArtic;

    cached_logo.resize(logo_buf->second);
    memcpy(cached_logo.data(), logo_buf->first, logo_buf->second);
    buffer = cached_logo;

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadProgramId(u64& out_program_id) {
    if (cached_title_id.has_value()) {
        out_program_id = *cached_title_id;
        return ResultStatus::Success;
    }

    if (!client_connected)
        client_connected = client->Connect();
    if (!client_connected)
        return ResultStatus::ErrorArtic;

    auto req = client->NewRequest("Process_GetTitleID");
    auto resp = client->Send(req);
    if (!resp.has_value())
        return ResultStatus::ErrorArtic;

    auto tid_buf = resp->GetResponseBuffer(0);
    if (!tid_buf.has_value() || tid_buf->second != sizeof(u64))
        return ResultStatus::ErrorArtic;

    out_program_id = *reinterpret_cast<u64*>(tid_buf->first);
    cached_title_id = out_program_id;

    return ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadExtdataId(u64& out_extdata_id) {
    if (program_exheader.arm11_system_local_caps.storage_info.other_attributes >> 1) {
        // Using extended save data access
        // There would be multiple possible extdata IDs in this case. The best we can do for now is
        // guessing that the first one would be the main save.
        const std::array<u64, 6> extdata_ids{{
            program_exheader.arm11_system_local_caps.storage_info.extdata_id0.Value(),
            program_exheader.arm11_system_local_caps.storage_info.extdata_id1.Value(),
            program_exheader.arm11_system_local_caps.storage_info.extdata_id2.Value(),
            program_exheader.arm11_system_local_caps.storage_info.extdata_id3.Value(),
            program_exheader.arm11_system_local_caps.storage_info.extdata_id4.Value(),
            program_exheader.arm11_system_local_caps.storage_info.extdata_id5.Value(),
        }};
        for (u64 id : extdata_ids) {
            if (id) {
                // Found a non-zero ID, use it
                out_extdata_id = id;
                return ResultStatus::Success;
            }
        }

        return ResultStatus::ErrorNotUsed;
    }

    out_extdata_id = program_exheader.arm11_system_local_caps.storage_info.ext_save_data_id;
    return Loader::ResultStatus::Success;
}

ResultStatus Apploader_Artic::ReadRomFS(std::shared_ptr<FileSys::RomFSReader>& romfs_file) {
    main_romfs_reader = romfs_file = std::make_shared<FileSys::ArticRomFSReader>(client, false);
    return static_cast<FileSys::ArticRomFSReader*>(romfs_file.get())->OpenStatus();
}

ResultStatus Apploader_Artic::ReadUpdateRomFS(std::shared_ptr<FileSys::RomFSReader>& romfs_file) {
    update_romfs_reader = romfs_file = std::make_shared<FileSys::ArticRomFSReader>(client, true);
    return static_cast<FileSys::ArticRomFSReader*>(romfs_file.get())->OpenStatus();
}

ResultStatus Apploader_Artic::DumpRomFS(const std::string& target_path) {
    return ResultStatus::ErrorNotImplemented;
}

ResultStatus Apploader_Artic::DumpUpdateRomFS(const std::string& target_path) {
    return ResultStatus::ErrorNotImplemented;
}

ResultStatus Apploader_Artic::ReadTitle(std::string& title) {
    std::vector<u8> data;
    Loader::SMDH smdh;
    ResultStatus result = ReadIcon(data);
    if (result != ResultStatus::Success) {
        return result;
    }

    if (!Loader::IsValidSMDH(data)) {
        return ResultStatus::ErrorInvalidFormat;
    }

    std::memcpy(&smdh, data.data(), sizeof(Loader::SMDH));

    const auto& short_title = smdh.GetShortTitle(SMDH::TitleLanguage::English);
    auto title_end = std::find(short_title.begin(), short_title.end(), u'\0');
    title = Common::UTF16ToUTF8(std::u16string{short_title.begin(), title_end});

    return ResultStatus::Success;
}

} // namespace Loader