// Copyright (C) 2015-2020 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include <config.h>

#include <dhcp/duid_factory.h>
#include <dhcpsrv/cfg_duid.h>
#include <util/encode/hex.h>
#include <util/strutil.h>
#include <iostream>
#include <string>
#include <string.h>

using namespace isc;
using namespace isc::data;
using namespace isc::util::encode;
using namespace isc::util::str;

namespace isc {
namespace dhcp {

CfgDUID::CfgDUID()
    : type_(DUID::DUID_LLT), identifier_(), htype_(0), time_(0),
      enterprise_id_(0), persist_(true) {
}

void
CfgDUID::setIdentifier(const std::string& identifier_as_hex) {
    // Remove whitespaces.
    const std::string identifier = trim(identifier_as_hex);
    // Temporary result of parsing.
    std::vector<uint8_t> binary;
    if (!identifier.empty()) {
        try {
            // Decode identifier specified as a string of hexadecimal digits.
            decodeHex(identifier, binary);
            // All went ok, so let's replace identifier with a new value.
            identifier_.swap(binary);
        } catch (const std::exception& ex) {
            isc_throw(BadValue, "identifier specified in the DUID"
                      " configuration '" << identifier
                      << "' is not a valid string of hexadecimal digits");
        }

    } else {
         // If specified identifier is empty, clear our internal identifier.
        identifier_.clear();
    }
}

DuidPtr
CfgDUID::create(const std::string& duid_file_path) {
    // Forget the current DUID.
    current_duid_.reset();

    // Use DUID factory to create a DUID instance.
    DUIDFactory factory(persist() ? duid_file_path : "");

    switch (getType()) {
    case DUID::DUID_LLT:
        factory.createLLT(getHType(), getTime(), getIdentifier());
        break;
    case DUID::DUID_EN:
        factory.createEN(getEnterpriseId(), getIdentifier());
        break;
    case DUID::DUID_LL:
        factory.createLL(getHType(), getIdentifier());
        break;
    default:
        // This should actually never happen.
        isc_throw(Unexpected, "invalid DUID type used " << getType()
                  << " to create a new DUID");
    }

    // Save the newly created DUID.
    current_duid_ = factory.get();

    // Return generated DUID.
    return (current_duid_);
}

ElementPtr
CfgDUID::toElement() const {
    ElementPtr result = Element::createMap();
    // Set user context
    contextToElement(result);
    // The type item is required
    std::string duid_type = "LLT";
    switch (type_) {
    case DUID::DUID_LLT:
        break;
    case DUID::DUID_EN:
        duid_type = "EN";
        break;
    case DUID::DUID_LL:
        duid_type = "LL";
        break;
    default:
        isc_throw(ToElementError, "invalid DUID type: " << getType());
        break;
    }
    result->set("type", Element::create(duid_type));
    // Set the identifier
    result->set("identifier",
                Element::create(util::encode::encodeHex(identifier_)));
    // Set the hardware type
    result->set("htype", Element::create(htype_));
    // Set the time
    result->set("time", Element::create(static_cast<long long>(time_)));
    // Set the enterprise id
    result->set("enterprise-id",
                Element::create(static_cast<long long>(enterprise_id_)));
    // Set the persistence flag
    result->set("persist", Element::create(persist_));
    return (result);
}

}
}