// Copyright 2020-2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "connections/implementation/pcp_manager.h"

#include <memory>
#include <string>
#include <utility>
#include <vector>

#include "absl/strings/string_view.h"
#include "connections/advertising_options.h"
#include "connections/connection_options.h"
#include "connections/discovery_options.h"
#include "connections/implementation/bwu_manager.h"
#include "connections/implementation/client_proxy.h"
#include "connections/implementation/endpoint_channel_manager.h"
#include "connections/implementation/endpoint_manager.h"
#include "connections/implementation/injected_bluetooth_device_store.h"
#include "connections/implementation/mediums/mediums.h"
#include "connections/implementation/p2p_cluster_pcp_handler.h"
#include "connections/implementation/p2p_point_to_point_pcp_handler.h"
#include "connections/implementation/p2p_star_pcp_handler.h"
#include "connections/implementation/pcp.h"
#include "connections/implementation/pcp_handler.h"
#include "connections/listeners.h"
#include "connections/medium_selector.h"
#include "connections/out_of_band_connection_metadata.h"
#include "connections/params.h"
#include "connections/status.h"
#include "connections/strategy.h"
#include "connections/v3/connection_listening_options.h"
#include "connections/v3/listeners.h"
#include "internal/interop/device.h"
#include "internal/platform/logging.h"

namespace nearby {
namespace connections {

PcpManager::PcpManager(
    Mediums& mediums, EndpointChannelManager& channel_manager,
    EndpointManager& endpoint_manager, BwuManager& bwu_manager,
    InjectedBluetoothDeviceStore& injected_bluetooth_device_store) {
  handlers_[Pcp::kP2pCluster] = std::make_unique<P2pClusterPcpHandler>(
      &mediums, &endpoint_manager, &channel_manager, &bwu_manager,
      injected_bluetooth_device_store);
  handlers_[Pcp::kP2pStar] = std::make_unique<P2pStarPcpHandler>(
      mediums, endpoint_manager, channel_manager, bwu_manager,
      injected_bluetooth_device_store);
  handlers_[Pcp::kP2pPointToPoint] =
      std::make_unique<P2pPointToPointPcpHandler>(
          mediums, endpoint_manager, channel_manager, bwu_manager,
          injected_bluetooth_device_store);
}

void PcpManager::DisconnectFromEndpointManager() {
  if (shutdown_.Set(true)) return;
  for (auto& item : handlers_) {
    if (!item.second) continue;
    item.second->DisconnectFromEndpointManager();
  }
}

PcpManager::~PcpManager() {
  LOG(INFO) << "Initiating shutdown of PcpManager.";
  DisconnectFromEndpointManager();
  LOG(INFO) << "PcpManager has shut down.";
}

Status PcpManager::StartAdvertising(
    ClientProxy* client, const std::string& service_id,
    const AdvertisingOptions& advertising_options,
    const ConnectionRequestInfo& info) {
  if (!SetCurrentPcpHandler(advertising_options.strategy)) {
    return {Status::kError};
  }

  client->SetWebRtcNonCellular(GetWebRtcNonCellular(
      advertising_options.CompatibleOptions().allowed.GetMediums(true)));

  return current_->StartAdvertising(client, service_id, advertising_options,
                                    info);
}

void PcpManager::StopAdvertising(ClientProxy* client) {
  if (current_) {
    current_->StopAdvertising(client);
  }
}

Status PcpManager::StartDiscovery(ClientProxy* client,
                                  const std::string& service_id,
                                  const DiscoveryOptions& discovery_options,
                                  DiscoveryListener listener) {
  if (!SetCurrentPcpHandler(discovery_options.strategy)) {
    return {Status::kError};
  }

  return current_->StartDiscovery(client, service_id, discovery_options,
                                  std::move(listener));
}

void PcpManager::StopDiscovery(ClientProxy* client) {
  if (current_) {
    current_->StopDiscovery(client);
  }
}

std::pair<Status, std::vector<ConnectionInfoVariant>>
PcpManager::StartListeningForIncomingConnections(
    ClientProxy* client, absl::string_view service_id,
    v3::ConnectionListener listener,
    const v3::ConnectionListeningOptions& options) {
  if (!SetCurrentPcpHandler(options.strategy)) {
    return {{Status::kError}, {}};
  }
  return {current_->StartListeningForIncomingConnections(
      client, service_id, options, std::move(listener))};
}

void PcpManager::StopListeningForIncomingConnections(ClientProxy* client) {
  if (current_) {
    current_->StopListeningForIncomingConnections(client);
  }
}

void PcpManager::InjectEndpoint(ClientProxy* client,
                                const std::string& service_id,
                                const OutOfBandConnectionMetadata& metadata) {
  if (current_) {
    current_->InjectEndpoint(client, service_id, metadata);
  }
}

Status PcpManager::RequestConnection(
    ClientProxy* client, const std::string& endpoint_id,
    const ConnectionRequestInfo& info,
    const ConnectionOptions& connection_options) {
  if (!current_) {
    return {Status::kOutOfOrderApiCall};
  }

  client->SetWebRtcNonCellular(
      GetWebRtcNonCellular(connection_options.GetMediums()));

  return current_->RequestConnection(client, endpoint_id, info,
                                     connection_options);
}

Status PcpManager::RequestConnectionV3(
    ClientProxy* client, const NearbyDevice& remote_device,
    const ConnectionRequestInfo& info,
    const ConnectionOptions& connection_options) {
  // TODO(b/300174495): Add test coverage for when |current_| is nullptr.
  if (!current_) {
    return {Status::kOutOfOrderApiCall};
  }

  return current_->RequestConnectionV3(client, remote_device, info,
                                       connection_options);
}

Status PcpManager::AcceptConnection(ClientProxy* client,
                                    const std::string& endpoint_id,
                                    PayloadListener payload_listener) {
  if (!current_) {
    return {Status::kOutOfOrderApiCall};
  }

  return current_->AcceptConnection(client, endpoint_id,
                                    std::move(payload_listener));
}

Status PcpManager::RejectConnection(ClientProxy* client,
                                    const std::string& endpoint_id) {
  if (!current_) {
    return {Status::kOutOfOrderApiCall};
  }

  return current_->RejectConnection(client, endpoint_id);
}

Status PcpManager::UpdateAdvertisingOptions(
    ClientProxy* client, absl::string_view service_id,
    const AdvertisingOptions& advertising_options) {
  if (!current_) {
    return {Status::kOutOfOrderApiCall};
  }
  return current_->UpdateAdvertisingOptions(client, service_id,
                                            advertising_options);
}

Status PcpManager::UpdateDiscoveryOptions(
    ClientProxy* client, absl::string_view service_id,
    const DiscoveryOptions& discovery_options) {
  if (!current_) {
    return {Status::kOutOfOrderApiCall};
  }
  return current_->UpdateDiscoveryOptions(client, service_id,
                                          discovery_options);
}

bool PcpManager::SetCurrentPcpHandler(Strategy strategy) {
  current_ = GetPcpHandler(StrategyToPcp(strategy));

  if (!current_) {
    LOG(ERROR) << "Failed to set current PCP handler: strategy="
               << strategy.GetName();
  }

  return current_;
}

PcpHandler* PcpManager::GetPcpHandler(Pcp pcp) const {
  auto item = handlers_.find(pcp);
  return item != handlers_.end() ? item->second.get() : nullptr;
}

bool PcpManager::GetWebRtcNonCellular(const std::vector<Medium>& mediums) {
  for (const auto& medium : mediums) {
    if (medium == Medium::WEB_RTC_NON_CELLULAR) {
      return true;
    }
  }
  return false;
}

}  // namespace connections
}  // namespace nearby