#include <security/pam_appl.h>
#include <security/pam_client.h>
#include <security/pam_ext.h>
#include <security/pam_misc.h>
#include <security/pam_modules.h>

#include <rublon/init.hpp>
#include <rublon/json.hpp>
#include <rublon/pam.hpp>
#include <rublon/rublon.hpp>
#include <rublon/utils.hpp>

#define DLL_PUBLIC __attribute__((visibility("default")))

using namespace std;

DLL_PUBLIC int pam_sm_setcred([[maybe_unused]] pam_handle_t * pamh,
  [[maybe_unused]] int flags,
  [[maybe_unused]] int argc,
  [[maybe_unused]] const char ** argv) {
    return PAM_SUCCESS;
}

DLL_PUBLIC int pam_sm_acct_mgmt([[maybe_unused]] pam_handle_t * pamh,
  [[maybe_unused]] int flags,
  [[maybe_unused]] int argc,
  [[maybe_unused]] const char ** argv) {
    return PAM_SUCCESS;
}

DLL_PUBLIC int
pam_sm_authenticate(pam_handle_t * pamh, [[maybe_unused]] int flags, [[maybe_unused]] int argc, [[maybe_unused]] const char ** argv) {
    using namespace rublon;

    LinuxPam pam{pamh};

    auto rublonConfig = ConfigurationFactory{}.systemConfig();
    if(not rublonConfig.has_value()) {
        pam.print("Rublon configuration not exists");
        pam.print("Please create /etc/rublon.config file");
        return PAM_SUCCESS;
    }

    std::byte sharedMemory[32 * 1024] = {};
    std::pmr::monotonic_buffer_resource mr{sharedMemory, std::size(sharedMemory)};
    std::pmr::unsynchronized_pool_resource rublonPoolResource{&mr};
    std::pmr::set_default_resource(&rublonPoolResource);

    CoreHandler CH{rublonConfig.value()};

    auto selectMethod  = [&](const MethodSelect & selector) { return selector.create(pam); };
    auto confirmMethod = [&](const PostMethod & confirm) { return confirm.fire(CH); };
    auto confirmCode   = [&](const MethodProxy & method) { return method.fire(CH, pam); };

    auto allowLogin = [&](const AuthenticationStatus & status) -> tl::expected< int, Error > {
        if(status.userAuthorized()) {
            rublon::log(rublon::LogLevel::Info, "Auth OK");
            pam.print("RUBLON authentication SUCCESS!\n");
            return PAM_SUCCESS;
        } else {
            rublon::log(rublon::LogLevel::Info, "User unauthorized");
            pam.print("RUBLON authentication FAILED");
            return PAM_MAXTRIES;
        }
    };

    auto mapError = [&](const Error & error) -> tl::expected< int, Error > {
        rublon::log(
          LogLevel::Error, "auth problems due to %d class and %d category", error.errorClass(), static_cast< int >(error.category()));
        if(error.is< PamBaypass >()) {
            pam.print("\n RUBLON authentication bypased");
            return PAM_SUCCESS;
        }
        pam.print("RUBLON authentication FAILED");
        rublon::log(LogLevel::Warning, "User login failed");

        return PAM_MAXTRIES;
    };

    auto ret = Init{rublonConfig.value()}
                 .fire(CH, pam) //
                 .and_then(selectMethod)
                 .and_then(confirmMethod)
                 .and_then(confirmCode)
                 .and_then(allowLogin)
                 .or_else(mapError);

    return ret.value_or(PAM_MAXTRIES);
}