/*
 *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#include "webrtc/base/checks.h"
#include "webrtc/p2p/base/portallocator.h"

namespace cricket {

PortAllocatorSession::PortAllocatorSession(const std::string& content_name,
                                           int component,
                                           const std::string& ice_ufrag,
                                           const std::string& ice_pwd,
                                           uint32_t flags)
    : flags_(flags),
      generation_(0),
      content_name_(content_name),
      component_(component),
      ice_ufrag_(ice_ufrag),
      ice_pwd_(ice_pwd) {
  // Pooled sessions are allowed to be created with empty content name,
  // component, ufrag and password.
  RTC_DCHECK(ice_ufrag.empty() == ice_pwd.empty());
}

bool PortAllocator::SetConfiguration(
    const ServerAddresses& stun_servers,
    const std::vector<RelayServerConfig>& turn_servers,
    int candidate_pool_size,
    bool prune_turn_ports) {
  bool ice_servers_changed =
      (stun_servers != stun_servers_ || turn_servers != turn_servers_);
  stun_servers_ = stun_servers;
  turn_servers_ = turn_servers;
  prune_turn_ports_ = prune_turn_ports;

  bool candidate_pool_drain_began =
      static_cast<int>(pooled_sessions_.size()) != candidate_pool_size_;
  if (candidate_pool_drain_began &&
      candidate_pool_size != candidate_pool_size_) {
    LOG(LS_ERROR) << "Trying to change candidate pool size after pool started "
                     "to be drained.";
    return false;
  }
  if (candidate_pool_size < 0) {
    LOG(LS_ERROR) << "Can't set negative pool size.";
    return false;
  }
  candidate_pool_size_ = candidate_pool_size;

  // If sessions need to be recreated, only recreate as many as the current
  // pool size if the pool has begun to be drained.
  int sessions_needed = candidate_pool_drain_began
                            ? static_cast<int>(pooled_sessions_.size())
                            : candidate_pool_size_;

  // If ICE servers changed, throw away any existing pooled sessions and create
  // new ones.
  if (ice_servers_changed) {
    pooled_sessions_.clear();
  }

  // If |sessions_needed| is less than the number of pooled sessions, get rid
  // of the extras.
  while (sessions_needed < static_cast<int>(pooled_sessions_.size())) {
    pooled_sessions_.front().reset(nullptr);
    pooled_sessions_.pop_front();
  }

  // If |sessions_needed| is greater than the number of pooled sessions,
  // create new sessions.
  while (static_cast<int>(pooled_sessions_.size()) < sessions_needed) {
    PortAllocatorSession* pooled_session = CreateSessionInternal("", 0, "", "");
    pooled_session->StartGettingPorts();
    pooled_sessions_.push_back(
        std::unique_ptr<PortAllocatorSession>(pooled_session));
  }
  return true;
}

std::unique_ptr<PortAllocatorSession> PortAllocator::CreateSession(
    const std::string& content_name,
    int component,
    const std::string& ice_ufrag,
    const std::string& ice_pwd) {
  auto session = std::unique_ptr<PortAllocatorSession>(
      CreateSessionInternal(content_name, component, ice_ufrag, ice_pwd));
  session->SetCandidateFilter(candidate_filter());
  return session;
}

std::unique_ptr<PortAllocatorSession> PortAllocator::TakePooledSession(
    const std::string& content_name,
    int component,
    const std::string& ice_ufrag,
    const std::string& ice_pwd) {
  RTC_DCHECK(!ice_ufrag.empty());
  RTC_DCHECK(!ice_pwd.empty());
  if (pooled_sessions_.empty()) {
    return nullptr;
  }
  std::unique_ptr<PortAllocatorSession> ret =
      std::move(pooled_sessions_.front());
  ret->SetIceParameters(content_name, component, ice_ufrag, ice_pwd);
  // According to JSEP, a pooled session should filter candidates only after
  // it's taken out of the pool.
  ret->SetCandidateFilter(candidate_filter());
  pooled_sessions_.pop_front();
  return ret;
}

const PortAllocatorSession* PortAllocator::GetPooledSession() const {
  if (pooled_sessions_.empty()) {
    return nullptr;
  }
  return pooled_sessions_.front().get();
}

}  // namespace cricket