#include "std_include.hpp"

#include <windows_emulator.hpp>
#include <backend_selection.hpp>
#include <win_x64_gdb_stub_handler.hpp>

#include "object_watching.hpp"
#include "snapshot.hpp"
#include "analysis.hpp"

#include <utils/interupt_handler.hpp>

#include <cstdio>

namespace
{
    struct analysis_options : analysis_settings
    {
        mutable bool use_gdb{false};
        std::filesystem::path dump{};
        std::string registry_path{"./registry"};
        std::string emulation_root{};
        std::unordered_map<windows_path, std::filesystem::path> path_mappings{};
    };

    void split_and_insert(std::set<std::string, std::less<>>& container, const std::string_view str,
                          const char splitter = ',')
    {
        size_t current_start = 0;
        for (size_t i = 0; i < str.size(); ++i)
        {
            const auto value = str[i];
            if (value != splitter)
            {
                continue;
            }

            if (current_start < i)
            {
                container.emplace(str.substr(current_start, i - current_start));
            }

            current_start = i + 1;
        }

        if (current_start < str.size())
        {
            container.emplace(str.substr(current_start));
        }
    }

    void watch_system_objects(windows_emulator& win_emu, const std::set<std::string, std::less<>>& modules,
                              const bool verbose)
    {
        win_emu.setup_process_if_necessary();

        (void)win_emu;
        (void)modules;
        (void)verbose;

#if !defined(__GNUC__) || defined(__clang__)
        watch_object(win_emu, modules, *win_emu.current_thread().teb, verbose);
        watch_object(win_emu, modules, win_emu.process.peb, verbose);
        watch_object(win_emu, modules, emulator_object<KUSER_SHARED_DATA64>{win_emu.emu(), kusd_mmio::address()},
                     verbose);

        auto* params_hook = watch_object(win_emu, modules, win_emu.process.process_params, verbose);

        win_emu.emu().hook_memory_write(
            win_emu.process.peb.value() + offsetof(PEB64, ProcessParameters), 0x8,
            [&win_emu, verbose, params_hook, modules](const uint64_t address, const void*, size_t) mutable {
                const auto target_address = win_emu.process.peb.value() + offsetof(PEB64, ProcessParameters);

                if (address == target_address)
                {
                    const emulator_object<RTL_USER_PROCESS_PARAMETERS64> obj{
                        win_emu.emu(),
                        win_emu.emu().read_memory<uint64_t>(address),
                    };

                    win_emu.emu().delete_hook(params_hook);
                    params_hook = watch_object(win_emu, modules, obj, verbose);
                }
            });
#endif
    }

    bool read_yes_no_answer()
    {
        while (true)
        {
            const auto chr = static_cast<char>(getchar());
            if (chr == 'y')
            {
                return true;
            }

            if (chr == 'n')
            {
                return false;
            }
        }
    }

    void do_post_emulation_work(const analysis_context& c)
    {
        if (c.settings->buffer_stdout)
        {
            c.win_emu->log.info("%.*s%s", static_cast<int>(c.output.size()), c.output.data(),
                                c.output.ends_with("\n") ? "" : "\n");
        }
    }

    bool run_emulation(const analysis_context& c, const analysis_options& options)
    {
        auto& win_emu = *c.win_emu;

        std::atomic_uint32_t signals_received{0};
        utils::interupt_handler _{[&] {
            const auto value = signals_received++;
            if (value == 1)
            {
                win_emu.log.log("Exit already requested. Press CTRL+C again to force kill!");
            }
            else if (value >= 2)
            {
                _Exit(1);
            }

            win_emu.stop();
        }};

        try
        {
            if (options.use_gdb)
            {
                const auto* address = "127.0.0.1:28960";
                win_emu.log.print(color::pink, "Waiting for GDB connection on %s...\n", address);

                const auto should_stop = [&] { return signals_received > 0; };

                win_x64_gdb_stub_handler handler{win_emu, should_stop};
                gdb_stub::run_gdb_stub(network::address{"0.0.0.0:28960", AF_INET}, handler);
            }
            else
            {
                win_emu.start();
            }

            if (signals_received > 0)
            {
                options.use_gdb = false;

                win_emu.log.log("Do you want to create a snapshot? (y/n)\n");
                const auto write_snapshot = read_yes_no_answer();

                if (write_snapshot)
                {
                    snapshot::write_emulator_snapshot(win_emu);
                }
            }
        }
        catch (const std::exception& e)
        {
            do_post_emulation_work(c);
            win_emu.log.error("Emulation failed at: 0x%" PRIx64 " - %s\n", win_emu.emu().read_instruction_pointer(),
                              e.what());
            throw;
        }
        catch (...)
        {
            do_post_emulation_work(c);
            win_emu.log.error("Emulation failed at: 0x%" PRIx64 "\n", win_emu.emu().read_instruction_pointer());
            throw;
        }

        const auto exit_status = win_emu.process.exit_status;
        if (!exit_status.has_value())
        {
            do_post_emulation_work(c);
            win_emu.log.error("Emulation terminated without status!\n");
            return false;
        }

        const auto success = *exit_status == STATUS_SUCCESS;

        if (!options.silent)
        {
            do_post_emulation_work(c);
            win_emu.log.disable_output(false);
            win_emu.log.print(success ? color::green : color::red, "Emulation terminated with status: %X\n",
                              *exit_status);
        }

        return success;
    }

    std::vector<std::u16string> parse_arguments(const std::span<const std::string_view> args)
    {
        std::vector<std::u16string> wide_args{};
        wide_args.reserve(args.size() - 1);

        for (size_t i = 1; i < args.size(); ++i)
        {
            const auto& arg = args[i];
            wide_args.emplace_back(arg.begin(), arg.end());
        }

        return wide_args;
    }

    emulator_settings create_emulator_settings(const analysis_options& options)
    {
        return {
            .emulation_root = options.emulation_root,
            .registry_directory = options.registry_path,
            .path_mappings = options.path_mappings,
        };
    }

    std::unique_ptr<windows_emulator> create_empty_emulator(const analysis_options& options)
    {
        const auto settings = create_emulator_settings(options);
        return std::make_unique<windows_emulator>(create_x86_64_emulator(), settings);
    }

    std::unique_ptr<windows_emulator> create_application_emulator(const analysis_options& options,
                                                                  const std::span<const std::string_view> args)
    {
        if (args.empty())
        {
            throw std::runtime_error("No args provided");
        }

        application_settings app_settings{
            .application = args[0],
            .arguments = parse_arguments(args),
        };

        const auto settings = create_emulator_settings(options);
        return std::make_unique<windows_emulator>(create_x86_64_emulator(), std::move(app_settings), settings);
    }

    std::unique_ptr<windows_emulator> setup_emulator(const analysis_options& options,
                                                     const std::span<const std::string_view> args)
    {
        if (options.dump.empty())
        {
            return create_application_emulator(options, args);
        }

        auto win_emu = create_empty_emulator(options);
        snapshot::load_emulator_snapshot(*win_emu, options.dump);
        return win_emu;
    }

    bool run(const analysis_options& options, const std::span<const std::string_view> args)
    {
        analysis_context context{
            .settings = &options,
        };

        const auto win_emu = setup_emulator(options, args);
        win_emu->log.disable_output(options.concise_logging || options.silent);
        context.win_emu = win_emu.get();

        win_emu->log.log("Using emulator: %s\n", win_emu->emu().get_name().c_str());

        register_analysis_callbacks(context);
        watch_system_objects(*win_emu, options.modules, options.verbose_logging);

        const auto& exe = *win_emu->mod_manager.executable;

        const auto concise_logging = !options.verbose_logging;

        for (const auto& section : exe.sections)
        {
            if ((section.region.permissions & memory_permission::exec) != memory_permission::exec)
            {
                continue;
            }

            auto read_handler = [&, section, concise_logging](const uint64_t address, const void*, size_t) {
                const auto rip = win_emu->emu().read_instruction_pointer();
                if (!win_emu->mod_manager.executable->is_within(rip))
                {
                    return;
                }

                if (concise_logging)
                {
                    static uint64_t count{0};
                    ++count;
                    if (count > 100 && count % 100000 != 0)
                    {
                        return;
                    }
                }

                win_emu->log.print(color::green,
                                   "Reading from executable section %s at 0x%" PRIx64 " via 0x%" PRIx64 "\n",
                                   section.name.c_str(), address, rip);
            };

            const auto write_handler = [&, section, concise_logging](const uint64_t address, const void*, size_t) {
                const auto rip = win_emu->emu().read_instruction_pointer();
                if (!win_emu->mod_manager.executable->is_within(rip))
                {
                    return;
                }

                if (concise_logging)
                {
                    static uint64_t count{0};
                    ++count;
                    if (count > 100 && count % 100000 != 0)
                    {
                        return;
                    }
                }

                win_emu->log.print(color::blue, "Writing to executable section %s at 0x%" PRIx64 " via 0x%" PRIx64 "\n",
                                   section.name.c_str(), address, rip);
            };

            win_emu->emu().hook_memory_read(section.region.start, section.region.length, std::move(read_handler));
            win_emu->emu().hook_memory_write(section.region.start, section.region.length, std::move(write_handler));
        }

        return run_emulation(context, options);
    }

    std::vector<std::string_view> bundle_arguments(const int argc, char** argv)
    {
        std::vector<std::string_view> args{};

        for (int i = 1; i < argc; ++i)
        {
            args.emplace_back(argv[i]);
        }

        return args;
    }

    void print_help()
    {
        printf("Usage: analyzer [options] [application] [args...]\n\n");
        printf("Options:\n");
        printf("  -h, --help                Show this help message\n");
        printf("  -d, --debug               Enable GDB debugging mode\n");
        printf("  -s, --silent              Silent mode\n");
        printf("  -v, --verbose             Verbose logging\n");
        printf("  -b, --buffer              Buffer stdout\n");
        printf("  -c, --concise             Concise logging\n");
        printf("  -m, --module <module>     Specify module to track\n");
        printf("  -e, --emulation <path>    Set emulation root path\n");
        printf("  -a, --snapshot <path>     Load snapshot dump from path\n");
        printf("  -i, --ignore <funcs>      Comma-separated list of functions to ignore\n");
        printf("  -p, --path <src> <dst>    Map Windows path to host path\n");
        printf("  -r, --registry <path>     Set registry path (default: ./registry)\n\n");
        printf("Examples:\n");
        printf("  analyzer -v -e path/to/root myapp.exe\n");
        printf("  analyzer -e path/to/root -p c:/analysis-sample.exe /path/to/sample.exe c:/analysis-sample.exe\n");
    }

    analysis_options parse_options(std::vector<std::string_view>& args)
    {
        analysis_options options{};

        while (!args.empty())
        {
            auto arg_it = args.begin();
            const auto& arg = *arg_it;

            if (arg == "-h" || arg == "--help")
            {
                print_help();
                std::exit(0);
            }
            else if (arg == "-d" || arg == "--debug")
            {
                options.use_gdb = true;
            }
            else if (arg == "-s" || arg == "--silent")
            {
                options.silent = true;
            }
            else if (arg == "-v" || arg == "--verbose")
            {
                options.verbose_logging = true;
            }
            else if (arg == "-b" || arg == "--buffer")
            {
                options.buffer_stdout = true;
            }
            else if (arg == "-c" || arg == "--concise")
            {
                options.concise_logging = true;
            }
            else if (arg == "-m" || arg == "--module")
            {
                if (args.size() < 2)
                {
                    throw std::runtime_error("No module provided after -m/--module");
                }

                arg_it = args.erase(arg_it);
                options.modules.insert(std::string(args[0]));
            }
            else if (arg == "-e" || arg == "--emulation")
            {
                if (args.size() < 2)
                {
                    throw std::runtime_error("No emulation root path provided after -e/--emulation");
                }
                arg_it = args.erase(arg_it);
                options.emulation_root = args[0];
            }
            else if (arg == "-a" || arg == "--snapshot")
            {
                if (args.size() < 2)
                {
                    throw std::runtime_error("No dump path provided after -a/--snapshot");
                }
                arg_it = args.erase(arg_it);
                options.dump = args[0];
            }
            else if (arg == "-i" || arg == "--ignore")
            {
                if (args.size() < 2)
                {
                    throw std::runtime_error("No ignored function(s) provided after -i/--ignore");
                }
                arg_it = args.erase(arg_it);
                split_and_insert(options.ignored_functions, args[0]);
            }
            else if (arg == "-p" || arg == "--path")
            {
                if (args.size() < 3)
                {
                    throw std::runtime_error("No path mapping provided after -p/--path");
                }
                arg_it = args.erase(arg_it);
                windows_path source = args[0];
                arg_it = args.erase(arg_it);
                std::filesystem::path target = std::filesystem::absolute(args[0]);

                options.path_mappings[std::move(source)] = std::move(target);
            }
            else if (arg == "-r" || arg == "--registry")
            {
                if (args.size() < 2)
                {
                    throw std::runtime_error("No registry path provided after -r/--registry");
                }
                arg_it = args.erase(arg_it);
                options.registry_path = args[0];
            }
            else
            {
                break;
            }

            args.erase(arg_it);
        }

        return options;
    }

    int run_main(const int argc, char** argv)
    {
        try
        {
            auto args = bundle_arguments(argc, argv);
            if (args.empty())
            {
                print_help();
                return 1;
            }

            const auto options = parse_options(args);

            bool result{};

            do
            {
                result = run(options, args);
            } while (options.use_gdb);

            return result ? 0 : 1;
        }
        catch (std::exception& e)
        {
            puts(e.what());

#if defined(_WIN32) && 0
            MessageBoxA(nullptr, e.what(), "ERROR", MB_ICONERROR);
#endif
        }

        return 1;
    }
}

int main(const int argc, char** argv)
{
    return run_main(argc, argv);
}

#ifdef _WIN32
int WINAPI WinMain(HINSTANCE, HINSTANCE, PSTR, int)
{
    return run_main(__argc, __argv);
}
#endif