// Copyright 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/core.h"

#include <cstdint>
#include <string>
#include <utility>
#include <vector>

#include "absl/strings/string_view.h"
#include "absl/time/time.h"
#include "absl/types/span.h"
#include "connections/advertising_options.h"
#include "connections/connection_options.h"
#include "connections/discovery_options.h"
#include "connections/implementation/service_controller_router.h"
#include "connections/implementation/service_id_constants.h"
#include "connections/listeners.h"
#include "connections/medium_selector.h"
#include "connections/out_of_band_connection_metadata.h"
#include "connections/params.h"
#include "connections/payload.h"
#include "connections/payload_type.h"
#include "connections/power_level.h"
#include "connections/status.h"
#include "connections/v3/advertising_options.h"
#include "connections/v3/bandwidth_info.h"
#include "connections/v3/connection_listening_options.h"
#include "connections/v3/connection_result.h"
#include "connections/v3/connections_device.h"
#include "connections/v3/discovery_options.h"
#include "connections/v3/listeners.h"
#include "connections/v3/listening_result.h"
#include "connections/v3/params.h"
#include "internal/interop/device.h"
#include "internal/platform/byte_array.h"
#include "internal/platform/count_down_latch.h"
#include "internal/platform/feature_flags.h"
#include "internal/platform/logging.h"

namespace nearby {
namespace connections {

namespace {

// Timeout for ServiceControllerRouter to run StopAllEndpoints.
constexpr absl::Duration kWaitForDisconnect = absl::Milliseconds(10000);

// Verify that |service_id| is not empty and will not conflict with any internal
// service ID formats.
void CheckServiceId(absl::string_view service_id) {
  CHECK(!service_id.empty());
  CHECK_NE(service_id, kUnknownServiceId);
  CHECK(!IsInitiatorUpgradeServiceId(service_id));
}

}  // namespace

Core::Core(ServiceControllerRouter* router) : router_(router) {}

Core::~Core() {
  CountDownLatch latch(1);
  router_->StopAllEndpoints(&client_, [&latch](Status) { latch.CountDown(); });
  if (!latch.Await(kWaitForDisconnect).result()) {
    LOG(FATAL) << "Unable to shutdown";
  }
}

Core::Core(Core&&) = default;

Core& Core::operator=(Core&&) = default;

void Core::StartAdvertising(absl::string_view service_id,
                            AdvertisingOptions advertising_options,
                            ConnectionRequestInfo info,
                            ResultCallback callback) {
  CheckServiceId(service_id);
  CHECK(advertising_options.strategy.IsValid());

  router_->StartAdvertising(&client_, service_id, advertising_options, info,
                            std::move(callback));
}

void Core::StopAdvertising(ResultCallback callback) {
  router_->StopAdvertising(&client_, std::move(callback));
}

void Core::StartDiscovery(absl::string_view service_id,
                          DiscoveryOptions discovery_options,
                          DiscoveryListener listener, ResultCallback callback) {
  CheckServiceId(service_id);
  CHECK(discovery_options.strategy.IsValid());

  router_->StartDiscovery(&client_, service_id, discovery_options,
                          std::move(listener), std::move(callback));
}

void Core::InjectEndpoint(absl::string_view service_id,
                          OutOfBandConnectionMetadata metadata,
                          ResultCallback callback) {
  CheckServiceId(service_id);
  router_->InjectEndpoint(&client_, service_id, metadata, std::move(callback));
}

void Core::StopDiscovery(ResultCallback callback) {
  router_->StopDiscovery(&client_, std::move(callback));
}

void Core::RequestConnection(absl::string_view endpoint_id,
                             ConnectionRequestInfo info,
                             ConnectionOptions connection_options,
                             ResultCallback callback) {
  if (endpoint_id.empty()) {
    callback(Status{.value = Status::kEndpointUnknown});
    return;
  }

  // Assign the default from feature flags for the keep-alive frame interval and
  // timeout values if client don't mind them or has the unexpected ones.
  if (connection_options.keep_alive_interval_millis == 0 ||
      connection_options.keep_alive_timeout_millis == 0 ||
      connection_options.keep_alive_interval_millis >=
          connection_options.keep_alive_timeout_millis) {
    LOG(WARNING)
        << "Client request connection with keep-alive frame as interval="
        << connection_options.keep_alive_interval_millis
        << ", timeout=" << connection_options.keep_alive_timeout_millis
        << ", which is un-expected. Change to default.";
    FeatureFlags::Flags flags = FeatureFlags::GetInstance().GetFlags();
    connection_options.keep_alive_interval_millis =
        flags.keep_alive_interval_millis;
    connection_options.keep_alive_timeout_millis =
        flags.keep_alive_timeout_millis;
  }

  router_->RequestConnection(&client_, endpoint_id, info, connection_options,
                             std::move(callback));
}

void Core::AcceptConnection(absl::string_view endpoint_id,
                            PayloadListener listener, ResultCallback callback) {
  if (endpoint_id.empty()) {
    callback(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->AcceptConnection(&client_, endpoint_id, std::move(listener),
                            std::move(callback));
}

void Core::RejectConnection(absl::string_view endpoint_id,
                            ResultCallback callback) {
  if (endpoint_id.empty()) {
    callback(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->RejectConnection(&client_, endpoint_id, std::move(callback));
}

void Core::InitiateBandwidthUpgrade(absl::string_view endpoint_id,
                                    ResultCallback callback) {
  router_->InitiateBandwidthUpgrade(&client_, endpoint_id, std::move(callback));
}

void Core::SendPayload(absl::Span<const std::string> endpoint_ids,
                       Payload payload, ResultCallback callback) {
  CHECK(payload.GetType() != PayloadType::kUnknown);
  CHECK(!endpoint_ids.empty());

  router_->SendPayload(&client_, endpoint_ids, std::move(payload),
                       std::move(callback));
}

void Core::CancelPayload(std::int64_t payload_id, ResultCallback callback) {
  CHECK_NE(payload_id, 0);

  router_->CancelPayload(&client_, payload_id, std::move(callback));
}

void Core::DisconnectFromEndpoint(absl::string_view endpoint_id,
                                  ResultCallback callback) {
  if (endpoint_id.empty()) {
    callback(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->DisconnectFromEndpoint(&client_, endpoint_id, std::move(callback));
}

void Core::StopAllEndpoints(ResultCallback callback) {
  router_->StopAllEndpoints(&client_, std::move(callback));
}

void Core::SetCustomSavePath(absl::string_view path, ResultCallback callback) {
  router_->SetCustomSavePath(&client_, path, std::move(callback));
}

void Core::OverrideSavePath(absl::string_view endpoint_id,
                            absl::string_view path) {
  client_.OverrideSavePath(endpoint_id, path);
}

std::string Core::Dump() { return client_.Dump(); }

// V3
void Core::StartAdvertisingV3(absl::string_view service_id,
                              const v3::AdvertisingOptions& advertising_options,
                              const NearbyDevice& local_device,
                              v3::ConnectionListener listener,
                              ResultCallback callback) {
  ConnectionListener old_listener = {
      .initiated_cb =
          [&listener](const std::string& endpoint_id,
                      const ConnectionResponseInfo& info) {
            auto remote_device = v3::ConnectionsDevice(
                endpoint_id, info.remote_endpoint_info.AsStringView(), {});
            listener.initiated_cb(
                remote_device,
                v3::InitialConnectionInfo{
                    .authentication_digits = info.authentication_token,
                    .raw_authentication_token =
                        info.raw_authentication_token.string_data(),
                    .is_incoming_connection = info.is_incoming_connection,
                });
          },
      .accepted_cb =
          [v3_cb = listener.result_cb](const std::string& endpoint_id) {
            auto remote_device = v3::ConnectionsDevice(endpoint_id, "", {});
            v3_cb(remote_device,
                  v3::ConnectionResult{.status = Status{
                                           .value = Status::kSuccess,
                                       }});
          },
      .rejected_cb =
          [v3_cb = listener.result_cb](const std::string& endpoint_id,
                                       Status status) {
            auto remote_device = v3::ConnectionsDevice(endpoint_id, "", {});
            v3_cb(remote_device, v3::ConnectionResult{
                                     .status = status,
                                 });
          },
      .disconnected_cb =
          [&listener](const std::string& endpoint_id) {
            auto remote_device = v3::ConnectionsDevice(endpoint_id, "", {});
            listener.disconnected_cb(remote_device);
          },
      .bandwidth_changed_cb =
          [&listener](const std::string& endpoint_id, Medium medium) {
            auto remote_device = v3::ConnectionsDevice(endpoint_id, "", {});
            listener.bandwidth_changed_cb(remote_device,
                                          v3::BandwidthInfo{.medium = medium});
          }};
  ByteArray local_endpoint_info;
  if (local_device.GetType() == NearbyDevice::kConnectionsDevice) {
    local_endpoint_info =
        ByteArray(reinterpret_cast<const v3::ConnectionsDevice&>(local_device)
                      .GetEndpointInfo());
  }
  ConnectionRequestInfo old_info = {
      .endpoint_info = local_endpoint_info,
      .listener = old_listener,
  };

  CheckServiceId(service_id);
  CHECK(advertising_options.strategy.IsValid());
  // TODO(b/291295755): Refactor deeper to use v3 options throughout.
  AdvertisingOptions old_advertising_options = {
      /*OptionsBase=*/
      {
          /*strategy=*/advertising_options.strategy,
          /*allowed=*/advertising_options.advertising_mediums,
      },
      /*auto_upgrade_bandwidth=*/advertising_options.auto_upgrade_bandwidth,
      /*enforce_topology_constraints=*/
      advertising_options.enforce_topology_constraints,
      /*low_power=*/advertising_options.power_level == PowerLevel::kLowPower,
      /*enable_bluetooth_listening=*/
      advertising_options.enable_bluetooth_listening,
      /*enable_webrtc_listening=*/
      advertising_options.advertising_mediums.web_rtc,
      /*use_stable_endpoint_id=*/advertising_options.use_stable_endpoint_id,
      /*force_new_endpoint_id=*/false,
      /*is_out_of_band_connection=*/false,
      /*fast_advertisement_service_uuid=*/
      advertising_options.fast_advertisement_service_uuid,
      /*device_info=*/""};
  router_->StartAdvertising(&client_, service_id, old_advertising_options,
                            old_info, std::move(callback));
}

void Core::StartAdvertisingV3(absl::string_view service_id,
                              const v3::AdvertisingOptions& advertising_options,
                              v3::ConnectionListener listener,
                              ResultCallback callback) {
  ByteArray local_endpoint_info;
  const NearbyDevice* local_device = client_.GetLocalDevice();
  if (local_device->GetType() == NearbyDevice::kConnectionsDevice) {
    local_endpoint_info =
        ByteArray(reinterpret_cast<const v3::ConnectionsDevice*>(local_device)
                      ->GetEndpointInfo());
  }
  StartAdvertisingV3(service_id, advertising_options, *local_device,
                     std::move(listener), std::move(callback));
}

void Core::StopAdvertisingV3(ResultCallback result_cb) {
  StopAdvertising(std::move(result_cb));
}

void Core::StartDiscoveryV3(absl::string_view service_id,
                            const v3::DiscoveryOptions& discovery_options,
                            v3::DiscoveryListener listener,
                            ResultCallback callback) {
  DiscoveryListener old_listener = {
      .endpoint_found_cb =
          [endpoint_found_cb = std::move(listener.endpoint_found_cb)](
              const std::string& endpoint_id, const ByteArray& endpoint_info,
              const std::string& service_id) mutable {
            auto remote_device = v3::ConnectionsDevice(
                endpoint_id, endpoint_info.AsStringView(), {});
            endpoint_found_cb(remote_device, service_id);
          },
      .endpoint_lost_cb =
          [endpoint_lost_cb = std::move(listener.endpoint_lost_cb)](
              const std::string& endpoint_id) mutable {
            auto remote_device = v3::ConnectionsDevice(endpoint_id, "", {});
            endpoint_lost_cb(remote_device);
          },
      .endpoint_distance_changed_cb =
          [endpoint_distance_changed_cb =
               std::move(listener.endpoint_distance_changed_cb)](
              const std::string& endpoint_id,
              DistanceInfo distance_info) mutable {
            auto remote = v3::ConnectionsDevice(endpoint_id, "", {});
            endpoint_distance_changed_cb(remote, distance_info);
          },
  };
  DiscoveryOptions old_discovery_options = {
      {
          discovery_options.strategy,
          discovery_options.discovery_mediums,
      },
      true,   // auto_upgrade_bandwidth
      true,   // enforce_topology_constraints
      false,  // is_out_of_band_connection
      discovery_options.fast_advertisement_service_uuid,
      discovery_options.power_level == PowerLevel::kLowPower,
  };
  // TODO(b/291295755): Deeper refactor to use v3 options throughout.
  StartDiscovery(service_id, old_discovery_options, std::move(old_listener),
                 std::move(callback));
}

void Core::StopDiscoveryV3(ResultCallback result_cb) {
  router_->StopDiscovery(&client_, std::move(result_cb));
}

void Core::StartListeningForIncomingConnectionsV3(
    const v3::ConnectionListeningOptions& options, absl::string_view service_id,
    v3::ConnectionListener listener_cb, v3::ListeningResultListener result_cb) {
  CHECK(options.listening_endpoint_type != NearbyDevice::Type::kUnknownDevice);

  router_->StartListeningForIncomingConnectionsV3(
      &client_, service_id, std::move(listener_cb), options,
      std::move(result_cb));
}

void Core::StopListeningForIncomingConnectionsV3() {
  router_->StopListeningForIncomingConnectionsV3(&client_);
}

void Core::RequestConnectionV3(const NearbyDevice& local_device,
                               const NearbyDevice& remote_device,
                               ConnectionOptions connection_options,
                               v3::ConnectionListener connection_cb,
                               ResultCallback result_cb) {
  CHECK(!remote_device.GetEndpointId().empty());

  v3::ConnectionRequestInfo info = {
      .local_device = const_cast<NearbyDevice&>(local_device),
      .listener = std::move(connection_cb),
  };

  // Assign the default from feature flags for the keep-alive frame interval and
  // timeout values if client don't mind them or has the unexpected ones.
  if (connection_options.keep_alive_interval_millis == 0 ||
      connection_options.keep_alive_timeout_millis == 0 ||
      connection_options.keep_alive_interval_millis >=
          connection_options.keep_alive_timeout_millis) {
    LOG(WARNING)
        << "Client request connection with keep-alive frame as interval="
        << connection_options.keep_alive_interval_millis
        << ", timeout=" << connection_options.keep_alive_timeout_millis
        << ", which is un-expected. Change to default.";
    FeatureFlags::Flags flags = FeatureFlags::GetInstance().GetFlags();
    connection_options.keep_alive_interval_millis =
        flags.keep_alive_interval_millis;
    connection_options.keep_alive_timeout_millis =
        flags.keep_alive_timeout_millis;
  }
  router_->RequestConnectionV3(&client_, remote_device, std::move(info),
                               connection_options, std::move(result_cb));
}

void Core::RequestConnectionV3(const NearbyDevice& remote_device,
                               ConnectionOptions connection_options,
                               v3::ConnectionListener connection_cb,
                               ResultCallback result_cb) {
  v3::ConnectionRequestInfo info = {
      .local_device = const_cast<NearbyDevice&>(*(client_.GetLocalDevice())),
      .listener = std::move(connection_cb),
  };
  if (remote_device.GetEndpointId().empty()) {
    result_cb(Status{.value = Status::kEndpointUnknown});
    return;
  }

  // Assign the default from feature flags for the keep-alive frame interval and
  // timeout values if client don't mind them or has the unexpected ones.
  if (connection_options.keep_alive_interval_millis == 0 ||
      connection_options.keep_alive_timeout_millis == 0 ||
      connection_options.keep_alive_interval_millis >=
          connection_options.keep_alive_timeout_millis) {
    LOG(WARNING)
        << "Client request connection with keep-alive frame as interval="
        << connection_options.keep_alive_interval_millis
        << ", timeout=" << connection_options.keep_alive_timeout_millis
        << ", which is un-expected. Change to default.";
    FeatureFlags::Flags flags = FeatureFlags::GetInstance().GetFlags();
    connection_options.keep_alive_interval_millis =
        flags.keep_alive_interval_millis;
    connection_options.keep_alive_timeout_millis =
        flags.keep_alive_timeout_millis;
  }
  router_->RequestConnectionV3(&client_, remote_device, std::move(info),
                               connection_options, std::move(result_cb));
}

void Core::AcceptConnectionV3(const NearbyDevice& remote_device,
                              v3::PayloadListener listener_cb,
                              ResultCallback result_cb) {
  if (remote_device.GetEndpointId().empty()) {
    result_cb(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->AcceptConnectionV3(&client_, remote_device, std::move(listener_cb),
                              std::move(result_cb));
}

void Core::RejectConnectionV3(const NearbyDevice& remote_device,
                              ResultCallback result_cb) {
  if (remote_device.GetEndpointId().empty()) {
    result_cb(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->RejectConnectionV3(&client_, remote_device, std::move(result_cb));
}

void Core::SendPayloadV3(const NearbyDevice& remote_device, Payload payload,
                         ResultCallback result_cb) {
  CHECK(payload.GetType() != PayloadType::kUnknown);
  if (remote_device.GetEndpointId().empty()) {
    result_cb(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->SendPayloadV3(&client_, remote_device, std::move(payload),
                         std::move(result_cb));
}

void Core::CancelPayloadV3(const NearbyDevice& remote_device,
                           int64_t payload_id, ResultCallback result_cb) {
  CHECK_NE(payload_id, 0);

  router_->CancelPayloadV3(&client_, remote_device, payload_id,
                           std::move(result_cb));
}

void Core::DisconnectFromDeviceV3(const NearbyDevice& remote_device,
                                  ResultCallback result_cb) {
  if (remote_device.GetEndpointId().empty()) {
    result_cb(Status{.value = Status::kEndpointUnknown});
    return;
  }

  router_->DisconnectFromDeviceV3(&client_, remote_device,
                                  std::move(result_cb));
}

void Core::StopAllDevicesV3(ResultCallback result_cb) {
  router_->StopAllEndpoints(&client_, std::move(result_cb));
}

void Core::InitiateBandwidthUpgradeV3(const NearbyDevice& remote_device,
                                      ResultCallback result_cb) {
  router_->InitiateBandwidthUpgradeV3(&client_, remote_device,
                                      std::move(result_cb));
}

void Core::UpdateAdvertisingOptionsV3(
    absl::string_view service_id, v3::AdvertisingOptions advertising_options,
    ResultCallback result_cb) {
  // TODO(b/291295755): Deeper refactor to use new advertising options.
  AdvertisingOptions old_advertising_options = {
      /*OptionsBase=*/
      {
          /*strategy=*/advertising_options.strategy,
          /*allowed=*/advertising_options.advertising_mediums,
      },
      /*auto_upgrade_bandwidth=*/advertising_options.auto_upgrade_bandwidth,
      /*enforce_topology_constraints=*/
      advertising_options.enforce_topology_constraints,
      /*low_power=*/advertising_options.power_level == PowerLevel::kLowPower,
      /*enable_bluetooth_listening=*/
      advertising_options.enable_bluetooth_listening,
      /*enable_webrtc_listening=*/
      advertising_options.advertising_mediums.web_rtc,
      /*use_stable_endpoint_id=*/advertising_options.use_stable_endpoint_id,
      /*force_new_endpoint_id=*/false,
      /*is_out_of_band_connection=*/false,
      /*fast_advertisement_service_uuid=*/
      advertising_options.fast_advertisement_service_uuid,
      /*device_info=*/""};
  router_->UpdateAdvertisingOptionsV3(
      &client_, service_id, old_advertising_options, std::move(result_cb));
}

void Core::UpdateDiscoveryOptionsV3(absl::string_view service_id,
                                    v3::DiscoveryOptions discovery_options,
                                    ResultCallback result_cb) {
  // TODO(b/291295755): Deeper refactor to use new discovery options.
  DiscoveryOptions old_discovery_options = {
      {
          discovery_options.strategy,
          discovery_options.discovery_mediums,
      },
      true,   // auto_upgrade_bandwidth
      true,   // enforce_topology_constraints
      false,  // is_out_of_band_connection
      discovery_options.fast_advertisement_service_uuid,
      discovery_options.power_level == PowerLevel::kLowPower,
  };
  router_->UpdateDiscoveryOptionsV3(&client_, service_id, old_discovery_options,
                                    std::move(result_cb));
}

}  // namespace connections
}  // namespace nearby