#include <hex/helpers/fs.hpp>

#include <hex/api/content_registry.hpp>
#include <hex/helpers/fs_macos.h>
#include <hex/helpers/file.hpp>
#include <hex/helpers/intrinsics.hpp>

#include <xdg.hpp>

#if defined(OS_WINDOWS)
    #include <windows.h>
    #include <shlobj.h>
#elif defined(OS_LINUX)
    #include <xdg.hpp>
    #include <linux/limits.h>
#endif

#include <algorithm>
#include <filesystem>

namespace hex::fs {

    std::optional<std::fs::path> getExecutablePath() {
#if defined(OS_WINDOWS)
        std::string exePath(MAX_PATH, '\0');
        if (GetModuleFileName(nullptr, exePath.data(), exePath.length()) == 0)
            return std::nullopt;

        return exePath;
#elif defined(OS_LINUX)
        std::string exePath(PATH_MAX, '\0');
        if (readlink("/proc/self/exe", exePath.data(), PATH_MAX) < 0)
            return std::nullopt;

        return exePath;
#elif defined(OS_MACOS)
        return getMacExecutableDirectoryPath();
#else
        return std::nullopt;
#endif
    }


    bool isPathWritable(const std::fs::path &path) {
        constexpr static auto TestFileName = "__imhex__tmp__";
        {
            File file(path / TestFileName, File::Mode::Read);
            if (file.isValid()) {
                if (!file.remove())
                    return false;
            }
        }

        File file(path / TestFileName, File::Mode::Create);
        bool result = file.isValid();
        if (!file.remove())
            return false;

        return result;
    }

    bool openFileBrowser(DialogMode mode, const std::vector<nfdfilteritem_t> &validExtensions, const std::function<void(std::fs::path)> &callback, const std::string &defaultPath) {
        NFD::Init();

        nfdchar_t *outPath;
        nfdresult_t result;
        switch (mode) {
            case DialogMode::Open:
                result = NFD::OpenDialog(outPath, validExtensions.data(), validExtensions.size(), defaultPath.c_str());
                break;
            case DialogMode::Save:
                result = NFD::SaveDialog(outPath, validExtensions.data(), validExtensions.size(), defaultPath.c_str());
                break;
            case DialogMode::Folder:
                result = NFD::PickFolder(outPath, defaultPath.c_str());
                break;
            default:
                hex::unreachable();
        }

        if (result == NFD_OKAY) {
            callback(reinterpret_cast<const char8_t *>(outPath));
            NFD::FreePath(outPath);
        }

        NFD::Quit();

        return result == NFD_OKAY;
    }


    std::vector<std::fs::path> getDefaultPaths(ImHexPath path, bool listNonExisting) {
        std::vector<std::fs::path> result;
        const auto exePath = getExecutablePath();
        const std::string settingName { "hex.builtin.setting.folders" };
        auto userDirs = ContentRegistry::Settings::read(settingName, settingName, std::vector<std::string> {});

        [[maybe_unused]]
        auto addUserDirs = [&userDirs](auto &paths) {
            std::transform(userDirs.begin(), userDirs.end(), std::back_inserter(paths), [](auto &item) {
                return std::move(item);
            });
        };

#if defined(OS_WINDOWS)
        std::fs::path appDataDir;
        {
            LPWSTR wAppDataPath = nullptr;
            if (!SUCCEEDED(SHGetKnownFolderPath(FOLDERID_LocalAppData, KF_FLAG_CREATE, nullptr, &wAppDataPath)))
                throw std::runtime_error("Failed to get APPDATA folder path");

            appDataDir = wAppDataPath;
            CoTaskMemFree(wAppDataPath);
        }

        std::vector<std::fs::path> paths = { appDataDir / "imhex" };

        if (exePath)
            paths.push_back(exePath->parent_path());

        switch (path) {
            case ImHexPath::Patterns:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "patterns").string();
                });
                break;
            case ImHexPath::PatternsInclude:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "includes").string();
                });
                break;
            case ImHexPath::Magic:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "magic").string();
                });
                break;
            case ImHexPath::Python:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "python").string();
                });
                break;
            case ImHexPath::Plugins:
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "plugins").string();
                });
                break;
            case ImHexPath::Yara:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "yara").string();
                });
                break;
            case ImHexPath::Config:
                return { (appDataDir / "imhex" / "config").string() };
            case ImHexPath::Resources:
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "resources").string();
                });
                break;
            case ImHexPath::Constants:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "constants").string();
                });
                break;
            case ImHexPath::Encodings:
                addUserDirs(paths);
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "encodings").string();
                });
                break;
            case ImHexPath::Logs:
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "logs").string();
                });
                break;
            default:
                hex::unreachable();
        }
#elif defined(OS_MACOS)
        // Get path to special directories
        const std::fs::path applicationSupportDir(getMacApplicationSupportDirectoryPath());

        std::vector<std::fs::path> paths = { applicationSupportDir };

        if (exePath)
            paths.push_back(exePath->parent_path());

        switch (path) {
            case ImHexPath::Patterns:
                result.push_back((applicationSupportDir / "patterns").string());
                break;
            case ImHexPath::PatternsInclude:
                result.push_back((applicationSupportDir / "includes").string());
                break;
            case ImHexPath::Magic:
                result.push_back((applicationSupportDir / "magic").string());
                break;
            case ImHexPath::Python:
                result.push_back((applicationSupportDir / "python").string());
                break;
            case ImHexPath::Plugins:
                std::transform(paths.begin(), paths.end(), std::back_inserter(result), [](auto &path) {
                    return (path / "plugins").string();
                });
                break;
            case ImHexPath::Yara:
                result.push_back((applicationSupportDir / "yara").string());
                break;
            case ImHexPath::Config:
                result.push_back((applicationSupportDir / "config").string());
                break;
            case ImHexPath::Resources:
                result.push_back((applicationSupportDir / "resources").string());
                break;
            case ImHexPath::Constants:
                result.push_back((applicationSupportDir / "constants").string());
                break;
            case ImHexPath::Encodings:
                result.push_back((applicationSupportDir / "encodings").string());
                break;
            case ImHexPath::Logs:
                result.push_back((applicationSupportDir / "logs").string());
                break;
            default:
                hex::unreachable();
        }
#else
        std::vector<std::fs::path> configDirs = xdg::ConfigDirs();
        std::vector<std::fs::path> dataDirs   = xdg::DataDirs();

        configDirs.push_back(xdg::ConfigHomeDir());
        dataDirs.push_back(xdg::DataHomeDir());

        for (auto &dir : dataDirs)
            dir = dir / "imhex";

        if (exePath && !exePath->empty())
            dataDirs.push_back(exePath->parent_path());

        switch (path) {
            case ImHexPath::Patterns:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "patterns").string(); });
                break;
            case ImHexPath::PatternsInclude:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "includes").string(); });
                break;
            case ImHexPath::Magic:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "magic").string(); });
                break;
            case ImHexPath::Python:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p).string(); });
                break;
            case ImHexPath::Plugins:
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "plugins").string(); });
                break;
            case ImHexPath::Yara:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "yara").string(); });
                break;
            case ImHexPath::Config:
                std::transform(configDirs.begin(), configDirs.end(), std::back_inserter(result), [](auto p) { return (p / "imhex").string(); });
                break;
            case ImHexPath::Resources:
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "resources").string(); });
                break;
            case ImHexPath::Constants:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "constants").string(); });
                break;
            case ImHexPath::Encodings:
                addUserDirs(dataDirs);
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "encodings").string(); });
                break;
            case ImHexPath::Logs:
                std::transform(dataDirs.begin(), dataDirs.end(), std::back_inserter(result), [](auto p) { return (p / "logs").string(); });
                break;
            default:
                hex::unreachable();
        }

#endif

        if (!listNonExisting) {
            result.erase(std::remove_if(result.begin(), result.end(), [](const auto &path) {
                return !fs::isDirectory(path);
            }),
                result.end());
        }

        return result;
    }

}