/*
 *  Copyright 2019 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 <atomic>
#include <memory>
#include <utility>
#include <vector>

#include "absl/memory/memory.h"
#include "api/test/simulated_network.h"
#include "call/simulated_network.h"
#include "rtc_base/event.h"
#include "rtc_base/logging.h"
#include "test/gmock.h"
#include "test/gtest.h"
#include "test/scenario/network/cross_traffic.h"
#include "test/scenario/network/network_emulation.h"
#include "test/scenario/network/network_emulation_manager.h"

namespace webrtc {
namespace test {
namespace {

class CountingBehavior : public NetworkBehaviorInterface {
 public:
  bool EnqueuePacket(PacketInFlightInfo packet_info) override {
    packets_to_send_.push_back(packet_info);
    return true;
  }

  std::vector<PacketDeliveryInfo> DequeueDeliverablePackets(
      int64_t receive_time_us) override {
    std::vector<PacketDeliveryInfo> out;
    for (auto packet : packets_to_send_) {
      // we want to count packets, that went through this behavior.
      packets_count_++;
      total_packets_size_ += packet.size;
      out.push_back(PacketDeliveryInfo(packet, receive_time_us));
    }
    packets_to_send_.clear();
    return out;
  }

  absl::optional<int64_t> NextDeliveryTimeUs() const override { return 1000; }

  int packets_count() const { return packets_count_; }
  uint64_t total_packets_size() const { return total_packets_size_; }

 private:
  std::vector<PacketInFlightInfo> packets_to_send_;

  std::atomic<int> packets_count_{0};
  std::atomic<uint64_t> total_packets_size_{0};
};

}  // namespace

TEST(CrossTrafficTest, TriggerPacketBurst) {
  NetworkEmulationManagerImpl network_manager;

  std::unique_ptr<CountingBehavior> behavior =
      absl::make_unique<CountingBehavior>();
  CountingBehavior* counter = behavior.get();

  EmulatedNetworkNode* node_a = network_manager.CreateEmulatedNode(
      absl::make_unique<SimulatedNetwork>(BuiltInNetworkBehaviorConfig()));
  EmulatedNetworkNode* node_b =
      network_manager.CreateEmulatedNode(std::move(behavior));

  TrafficRoute* traffic = network_manager.CreateTrafficRoute({node_a, node_b});

  traffic->TriggerPacketBurst(100, 1000);

  rtc::Event event;
  event.Wait(1000);

  EXPECT_EQ(counter->packets_count(), 100);
  EXPECT_EQ(counter->total_packets_size(), 100 * 1000ul);
}

TEST(CrossTrafficTest, PulsedPeaksCrossTraffic) {
  NetworkEmulationManagerImpl network_manager;

  std::unique_ptr<CountingBehavior> behavior =
      absl::make_unique<CountingBehavior>();
  CountingBehavior* counter = behavior.get();

  EmulatedNetworkNode* node_a = network_manager.CreateEmulatedNode(
      absl::make_unique<SimulatedNetwork>(BuiltInNetworkBehaviorConfig()));
  EmulatedNetworkNode* node_b =
      network_manager.CreateEmulatedNode(std::move(behavior));

  PulsedPeaksConfig config;
  config.peak_rate = DataRate::kbps(1000);
  config.min_packet_size = DataSize::bytes(1);
  config.min_packet_interval = TimeDelta::ms(25);
  config.send_duration = TimeDelta::ms(500);
  config.hold_duration = TimeDelta::ms(250);
  TrafficRoute* traffic = network_manager.CreateTrafficRoute({node_a, node_b});
  network_manager.CreatePulsedPeaksCrossTraffic(traffic, config);
  const auto kRunTime = TimeDelta::seconds(1);

  rtc::Event event;
  event.Wait(kRunTime.ms());

  RTC_LOG(INFO) << counter->packets_count() << " packets; "
                << counter->total_packets_size() << " bytes";
  // Using 50% duty cycle.
  const auto kExpectedDataSent = kRunTime * config.peak_rate * 0.5;
  EXPECT_NEAR(counter->total_packets_size(), kExpectedDataSent.bytes(),
              kExpectedDataSent.bytes() * 0.1);
}

TEST(CrossTrafficTest, RandomWalkCrossTraffic) {
  NetworkEmulationManagerImpl network_manager;

  std::unique_ptr<CountingBehavior> behavior =
      absl::make_unique<CountingBehavior>();
  CountingBehavior* counter = behavior.get();

  EmulatedNetworkNode* node_a = network_manager.CreateEmulatedNode(
      absl::make_unique<SimulatedNetwork>(BuiltInNetworkBehaviorConfig()));
  EmulatedNetworkNode* node_b =
      network_manager.CreateEmulatedNode(std::move(behavior));

  RandomWalkConfig config;
  config.peak_rate = DataRate::kbps(1000);
  config.min_packet_size = DataSize::bytes(1);
  config.min_packet_interval = TimeDelta::ms(25);
  config.update_interval = TimeDelta::ms(500);
  config.variance = 0.0;
  config.bias = 1.0;
  TrafficRoute* traffic = network_manager.CreateTrafficRoute({node_a, node_b});
  network_manager.CreateRandomWalkCrossTraffic(traffic, config);
  const auto kRunTime = TimeDelta::seconds(1);

  rtc::Event event;
  event.Wait(kRunTime.ms());

  RTC_LOG(INFO) << counter->packets_count() << " packets; "
                << counter->total_packets_size() << " bytes";
  // Sending at peak rate since bias = 1.
  const auto kExpectedDataSent = kRunTime * config.peak_rate;
  EXPECT_NEAR(counter->total_packets_size(), kExpectedDataSent.bytes(),
              kExpectedDataSent.bytes() * 0.1);
}

}  // namespace test
}  // namespace webrtc