#include "generate-root.hpp"
#include <boost/program_options.hpp>
#include <chrono>
#include <iostream>
#include <stdexcept>
#include <vanetza/common/clock.hpp>
#include <vanetza/common/its_aid.hpp>
#include <vanetza/security/backend_cryptopp.hpp>
#include <vanetza/security/v2/basic_elements.hpp>
#include <vanetza/security/v2/certificate.hpp>
#include <vanetza/security/v2/persistence.hpp>
#include <vanetza/security/v2/subject_attribute.hpp>
#include <vanetza/security/v2/subject_info.hpp>

namespace aid = vanetza::aid;
namespace po = boost::program_options;
using namespace vanetza::security;

bool GenerateRootCommand::parse(const std::vector<std::string>& opts)
{
    po::options_description desc("Available options");
    desc.add_options()
        ("help", "Print out available options.")
        ("output", po::value<std::string>(&output)->required(), "Output file.")
        ("subject-key", po::value<std::string>(&subject_key_path)->required(), "Private key file.")
        ("subject-name", po::value<std::string>(&subject_name)->default_value("Hello World Root-CA"), "Subject name.")
        ("days", po::value<int>(&validity_days)->default_value(365), "Validity in days.")
        ("aid", po::value<std::vector<unsigned> >(&aids)->multitoken(), "Allowed ITS-AIDs to restrict permissions, defaults to 36 (CA) and 37 (DEN) if empty.")
    ;

    po::positional_options_description pos;
    pos.add("output", 1);

    po::variables_map vm;
    po::store(po::command_line_parser(opts).options(desc).positional(pos).run(), vm);

    if (vm.count("help")) {
        std::cerr << desc << std::endl;

        return false;
    }

    try {
        po::notify(vm);
    } catch (const std::exception& e) {
        std::cerr << "Error: " << e.what() << std::endl << std::endl << desc << std::endl;

        return false;
    }

    return true;
}

int GenerateRootCommand::execute()
{
    auto backend = create_backend_or_throw("default");

    std::cout << "Loading key... ";
    auto subject_key = v2::load_private_key_from_file(subject_key_path);
    std::cout << "OK" << std::endl;

    auto time_now = vanetza::Clock::at(boost::posix_time::microsec_clock::universal_time());

    // create certificate
    v2::Certificate certificate;
    std::list<v2::IntX> certificate_aids;

    if (aids.size()) {
        for (unsigned aid : aids) {
            certificate_aids.push_back(v2::IntX(aid));
        }
    } else {
        certificate_aids.push_back(v2::IntX(aid::CA));
        certificate_aids.push_back(v2::IntX(aid::DEN));
    }
    certificate.subject_attributes.push_back(certificate_aids);

    // section 6.1 in TS 103 097 v1.2.1
    certificate.signer_info = nullptr; /* self */

    // section 6.3 in TS 103 097 v1.2.1
    certificate.subject_info.subject_type = v2::SubjectType::Root_CA;

    // section 7.4.2 in TS 103 097 v1.2.1
    std::vector<unsigned char> subject(subject_name.begin(), subject_name.end());
    certificate.subject_info.subject_name = subject;

    // section 6.6 in TS 103 097 v1.2.1 - levels currently undefined
    certificate.subject_attributes.push_back(v2::SubjectAssurance(0x00));

    // section 7.4.1 in TS 103 097 v1.2.1
    // set subject attributes
    // set the verification_key
    Uncompressed coordinates;
    coordinates.x.assign(subject_key.public_key.x.begin(), subject_key.public_key.x.end());
    coordinates.y.assign(subject_key.public_key.y.begin(), subject_key.public_key.y.end());
    EccPoint ecc_point = coordinates;
    v2::ecdsa_nistp256_with_sha256 ecdsa;
    ecdsa.public_key = ecc_point;
    v2::VerificationKey verification_key;
    verification_key.key = ecdsa;
    certificate.subject_attributes.push_back(verification_key);

    // section 6.7 in TS 103 097 v1.2.1
    // set validity restriction
    v2::StartAndEndValidity start_and_end;
    start_and_end.start_validity = v2::convert_time32(time_now - std::chrono::hours(1));
    start_and_end.end_validity = v2::convert_time32(time_now + std::chrono::hours(24 * validity_days));
    certificate.validity_restriction.push_back(start_and_end);

    std::cout << "Signing certificate... ";

    sort(certificate);
    vanetza::ByteBuffer data_buffer = convert_for_signing(certificate);
    certificate.signature = backend->sign_data(subject_key.private_key, data_buffer);

    std::cout << "OK" << std::endl;

    std::cout << "Writing certificate to '" << output << "'... ";
    save_certificate_to_file(output, certificate);
    std::cout << "OK" << std::endl;

    return 0;
}