/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2022,  Regents of the University of California,
 *                           Arizona Board of Regents,
 *                           Colorado State University,
 *                           University Pierre & Marie Curie, Sorbonne University,
 *                           Washington University in St. Louis,
 *                           Beijing Institute of Technology,
 *                           The University of Memphis.
 *
 * This file is part of NFD (Named Data Networking Forwarding Daemon).
 * See AUTHORS.md for complete list of NFD authors and contributors.
 *
 * NFD is free software: you can redistribute it and/or modify it under the terms
 * of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 of the License, or (at your option) any later version.
 *
 * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 * PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "tables-config-section.hpp"
#include "fw/strategy.hpp"

namespace nfd {

constexpr size_t DEFAULT_CS_MAX_PACKETS = 65536;

TablesConfigSection::TablesConfigSection(Forwarder& forwarder)
  : m_forwarder(forwarder)
  , m_isConfigured(false)
{
}

void
TablesConfigSection::setConfigFile(ConfigFile& configFile)
{
  configFile.addSectionHandler("tables", [this] (auto&&... args) {
    processConfig(std::forward<decltype(args)>(args)...);
  });
}

void
TablesConfigSection::ensureConfigured()
{
  if (m_isConfigured) {
    return;
  }

  m_forwarder.getCs().setLimit(DEFAULT_CS_MAX_PACKETS);
  // Don't set default cs_policy because it's already created by CS itself.
  m_forwarder.setUnsolicitedDataPolicy(make_unique<fw::DefaultUnsolicitedDataPolicy>());

  m_isConfigured = true;
}

void
TablesConfigSection::processConfig(const ConfigSection& section, bool isDryRun, const std::string&)
{
  size_t nCsMaxPackets = DEFAULT_CS_MAX_PACKETS;
  OptionalConfigSection csMaxPacketsNode = section.get_child_optional("cs_max_packets");
  if (csMaxPacketsNode) {
    nCsMaxPackets = ConfigFile::parseNumber<size_t>(*csMaxPacketsNode, "cs_max_packets", "tables");
  }

  unique_ptr<cs::Policy> csPolicy;
  OptionalConfigSection csPolicyNode = section.get_child_optional("cs_policy");
  if (csPolicyNode) {
    std::string policyName = csPolicyNode->get_value<std::string>();
    csPolicy = cs::Policy::create(policyName);
    if (csPolicy == nullptr) {
      NDN_THROW(ConfigFile::Error("Unknown cs_policy '" + policyName + "' in section 'tables'"));
    }
  }

  unique_ptr<fw::UnsolicitedDataPolicy> unsolicitedDataPolicy;
  OptionalConfigSection unsolicitedDataPolicyNode = section.get_child_optional("cs_unsolicited_policy");
  if (unsolicitedDataPolicyNode) {
    std::string policyName = unsolicitedDataPolicyNode->get_value<std::string>();
    unsolicitedDataPolicy = fw::UnsolicitedDataPolicy::create(policyName);
    if (unsolicitedDataPolicy == nullptr) {
      NDN_THROW(ConfigFile::Error("Unknown cs_unsolicited_policy '" + policyName + "' in section 'tables'"));
    }
  }
  else {
    unsolicitedDataPolicy = make_unique<fw::DefaultUnsolicitedDataPolicy>();
  }

  OptionalConfigSection strategyChoiceSection = section.get_child_optional("strategy_choice");
  if (strategyChoiceSection) {
    processStrategyChoiceSection(*strategyChoiceSection, isDryRun);
  }

  OptionalConfigSection networkRegionSection = section.get_child_optional("network_region");
  if (networkRegionSection) {
    processNetworkRegionSection(*networkRegionSection, isDryRun);
  }

  if (isDryRun) {
    return;
  }

  Cs& cs = m_forwarder.getCs();
  cs.setLimit(nCsMaxPackets);
  if (cs.size() == 0 && csPolicy != nullptr) {
    cs.setPolicy(std::move(csPolicy));
  }

  m_forwarder.setUnsolicitedDataPolicy(std::move(unsolicitedDataPolicy));

  m_isConfigured = true;
}

void
TablesConfigSection::processStrategyChoiceSection(const ConfigSection& section, bool isDryRun)
{
  std::map<Name, Name> choices;
  for (const auto& prefixAndStrategy : section) {
    Name prefix(prefixAndStrategy.first);
    Name strategy(prefixAndStrategy.second.get_value<std::string>());

    if (!fw::Strategy::canCreate(strategy)) {
      NDN_THROW(ConfigFile::Error("Unknown strategy '" + prefixAndStrategy.second.get_value<std::string>() +
                                  "' for prefix '" + prefix.toUri() + "' in section 'strategy_choice'"));
    }

    if (!choices.try_emplace(prefix, std::move(strategy)).second) {
      NDN_THROW(ConfigFile::Error("Duplicate strategy choice for prefix '" + prefix.toUri() +
                                  "' in section 'strategy_choice'"));
    }
  }

  if (isDryRun) {
    return;
  }

  StrategyChoice& sc = m_forwarder.getStrategyChoice();
  for (const auto& prefixAndStrategy : choices) {
    if (!sc.insert(prefixAndStrategy.first, prefixAndStrategy.second)) {
      NDN_THROW(ConfigFile::Error(
        "Failed to set strategy '" + prefixAndStrategy.second.toUri() + "' for prefix '" +
        prefixAndStrategy.first.toUri() + "' in section 'strategy_choice'"));
    }
  }
  ///\todo redesign so that strategy parameter errors can be catched during dry-run
}

void
TablesConfigSection::processNetworkRegionSection(const ConfigSection& section, bool isDryRun)
{
  if (isDryRun) {
    return;
  }

  auto& nrt = m_forwarder.getNetworkRegionTable();
  nrt.clear();
  for (const auto& pair : section) {
    nrt.insert(Name(pair.first));
  }
}

} // namespace nfd