rublon-ssh/PAM/ssh/include/rublon/check_application.hpp

#pragma once

#include <rublon/bits.hpp>
#include <rublon/core_handler.hpp>
#include <rublon/curl.hpp>
#include <rublon/error.hpp>
#include <rublon/json.hpp>
#include <rublon/memory.hpp>
#include <rublon/utils.hpp>

#include <rapidjson/prettywriter.h>
#include <rapidjson/rapidjson.h>

namespace rublon {

std::string exec(const char * cmd) {
    std::array< char, 128 > buffer;
    std::string result;
    std::unique_ptr< FILE, decltype(&pclose) > pipe(popen(cmd, "r"), pclose);
    if(!pipe) {
        return "";
    }
    while(fgets(buffer.data(), static_cast< int >(buffer.size()), pipe.get()) != nullptr) {
        result += buffer.data();
    }
    return result;
}

std::map< std::string, std::string > getSSHDConfig() {
    std::istringstream iss(exec("sshd -T"));
    std::map< std::string, std::string > result;
    for(std::string line; std::getline(iss, line);) {
        auto first_token    = line.substr(0, line.find(' '));
        result[first_token] = line.substr(line.find(' ') + 1);
    }
    return result;
}

class Status {
    std::string_view _statusDirPath  = "/var/lib/rublon";
    std::string_view _statusFilePath = "/var/lib/rublon/install.json";

    RapidJSONPMRStackAlloc< 4 * 1024 > _alloc;
    Document _data;
    bool _statusUpdated;

    std::string_view _appVersionKey   = "/appVer";
    std::string_view _appTypeKey      = "/type";
    std::string_view _paramSystemName = "/params/os";
    std::string_view _paramSSHDBase   = "/params/sshd_config/";

  public:
    Status() : _alloc{}, _data{&_alloc}, _statusUpdated{false} {
        if(not details::exists(_statusFilePath.data())) {
            log(LogLevel::Info, "application first run, creating status file at %s", _statusFilePath.data());
            details::mkdir(_statusDirPath.data());
            details::touch(_statusFilePath.data());
        }

        std::ifstream ifs{_statusFilePath.data()};
        if(!ifs.is_open()) {
            /// TODO handle no file error
        }

        rapidjson::IStreamWrapper isw{ifs};
        _data.ParseStream(isw);
    }

    void updateAppVersion(std::string_view newVersion) {
        RapidJSONPMRStackAlloc< 128 > stackAlloc;
        auto jsonPointer = JSONPointer{_appVersionKey.data(), &stackAlloc};
        auto version     = jsonPointer.Get(_data);
        if(not version || version->GetString() != newVersion) {
            markUpdated();
            jsonPointer.Set(_data, Value{newVersion.data(), _data.GetAllocator()});
        }
    }

    void updateSystemVersion(std::string_view system) {
        RapidJSONPMRStackAlloc< 128 > stackAlloc;
        auto jsonPointer = JSONPointer{_paramSystemName.data(), &stackAlloc};
        auto version     = jsonPointer.Get(_data);
        if(not version || version->GetString() != system) {
            markUpdated();
            jsonPointer.Set(_data, Value{system.data(), _data.GetAllocator()});
        }
    }

    void updateSSHDConfig() {
        using namespace std::string_view_literals;
        constexpr auto keys = make_array("authenticationmethods"sv,
          "challengeresponseauthentication"sv,
          "kbdinteractiveauthentication"sv,
          "logingracetime"sv,
          "maxauthtries"sv,
          "passwordauthentication"sv,
          "permitemptypasswords"sv,
          "permitrootlogin"sv,
          "pubkeyauthentication"sv,
          "usepam"sv);

        auto config = getSSHDConfig();

        for(const auto key : keys) {
            auto [currentPair, inserted]      = config.try_emplace(std::string{key.data()}, "N/A");
            auto & [currentKey, currentValue] = *currentPair;

            const auto jsonPath = std::string{_paramSSHDBase.data()} + key.data();

            RapidJSONPMRStackAlloc< 512 > stackAlloc;
            auto jsonPointer = JSONPointer{jsonPath.c_str(), &stackAlloc};

            auto oldValue = jsonPointer.Get(_data);

            if(not oldValue || oldValue->GetString() != currentValue) {
                _statusUpdated = true;
                jsonPointer.Set(_data, Value{currentValue.c_str(), _data.GetAllocator()});
            }
        }
    }

    void markUpdated() {
        _statusUpdated = true;
    }

    bool updated() const {
        return _statusUpdated;
    }

    void save() {
        if(updated()) {
            memory::Monotonic_8k_HeapResource tmpResource;
            RapidJSONPMRAlloc alloc{&tmpResource};
            FileWriter s{_statusFilePath};
            rapidjson::PrettyWriter< FileWriter, rapidjson::UTF8<>, rapidjson::UTF8<>, RapidJSONPMRAlloc > writer{s, &alloc};
            writer.SetIndent(' ', 2);
            _data.Accept(writer);
        }
    }

    std::string print() {
        std::string result;
        memory::Monotonic_8k_HeapResource tmpResource;
        RapidJSONPMRAlloc alloc{&tmpResource};
        StringWriter s{result};
        rapidjson::PrettyWriter< StringWriter< std::string >, rapidjson::UTF8<>, rapidjson::UTF8<>, RapidJSONPMRAlloc > writer{s, &alloc};
        writer.SetIndent(' ', 2);
        _data.Accept(writer);

        return result;
    }

    Document & data() {
        return _data;
    }
};

class CheckApplication {
    tl::expected< bool, Error > persistStatus(Status & status) const {
        status.data().RemoveMember("systemToken");
        status.save();
        return true;
    }

  public:
    tl::expected< int, Error > call(const CoreHandler_t & coreHandler, std::string_view systemToken) const {
        memory::Monotonic_1k_HeapResource mr;
        RapidJSONPMRStackAlloc< 2048 > alloc{};
        constexpr std::string_view api = "/api/app/init";
        Status status;

        const auto persist = [&](const auto /*ok*/) { return this->persistStatus(status); };

        status.updateAppVersion(RUBLON_VERSION_STRING);
        status.updateSystemVersion(details::osName(&mr));
        status.updateSSHDConfig();

        if(status.updated()) {
            auto & alloc = status.data().GetAllocator();
            status.data().AddMember("systemToken", Value{systemToken.data(), alloc}, alloc);
            return coreHandler.request(alloc, api, status.data()).and_then(persist);
        }
        return 0;
    }
};

} // namespace rublon