/*
 * Copyright (C) Photon Vision.
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <gtest/gtest.h>
#include <hal/HAL.h>
#include <net/TimeSyncClient.h>
#include <net/TimeSyncServer.h>

TEST(TimeSyncProtocolTest, Smoketest) {
  using namespace wpi::tsp;
  using namespace std::chrono_literals;

  TimeSyncServer server{5812};
  TimeSyncClient client{"127.0.0.1", 5812, 100ms};

  server.Start();
  client.Start();

  for (int i = 0; i < 10; i++) {
    std::this_thread::sleep_for(100ms);
    TimeSyncClient::Metadata m = client.GetMetadata();
    wpi::println("Offset={} rtt={}", m.offset, m.rtt2);
  }

  server.Stop();
}

TEST(TimeSyncClientTest, CalculateZero) {
  using namespace wpi::tsp;
  using namespace std::chrono_literals;

  // GIVEN a fresh client
  TimeSyncClient client{"127.0.0.1", 5812, 100ms};

  // AND a ping-pong sent with no delay
  // client -> server -> client
  uint64_t ping_client_time{100};
  uint64_t pong_server_time{100};
  uint64_t pong_client_time{100};

  // setup our ping/pong packets
  TspPing ping{.version = 1, .message_id = 1, .client_time = ping_client_time};
  TspPong pong{ping, pong_server_time};

  // WHEN we update statistics
  client.UpdateStatistics(pong_client_time, ping, pong);

  // THEN the statistics will reflect no delay
  EXPECT_EQ(0, client.GetMetadata().offset);
  EXPECT_EQ(0, client.GetMetadata().rtt2);
  EXPECT_EQ(1u, client.GetMetadata().pongsReceived);
  EXPECT_EQ(pong_client_time, client.GetMetadata().lastPongTime);
}

TEST(TimeSyncClientTest, CalculateZeroOffset) {
  using namespace wpi::tsp;
  using namespace std::chrono_literals;

  // GIVEN a fresh client
  TimeSyncClient client{"127.0.0.1", 5812, 100ms};

  // AND a ping-pong sent with 10ms delay each way
  // client -> server -> client
  uint64_t ping_client_time{100};
  uint64_t pong_server_time{110};
  uint64_t pong_client_time{120};

  // setup our ping/pong packets
  TspPing ping{.version = 1, .message_id = 1, .client_time = ping_client_time};
  TspPong pong{ping, pong_server_time};

  // WHEN we update statistics
  client.UpdateStatistics(pong_client_time, ping, pong);

  // THEN the statistics will reflect no offset, and the expected rtt2
  // (client-to-client) latency
  EXPECT_EQ(0, client.GetMetadata().offset);
  EXPECT_EQ(20, client.GetMetadata().rtt2);
  EXPECT_EQ(1u, client.GetMetadata().pongsReceived);
  EXPECT_EQ(pong_client_time, client.GetMetadata().lastPongTime);
}

TEST(TimeSyncClientTest, CalculateZeroRtt) {
  using namespace wpi::tsp;
  using namespace std::chrono_literals;

  // GIVEN a fresh client
  TimeSyncClient client{"127.0.0.1", 5812, 100ms};

  // AND a ping-pong sent with no delay
  // client -> server -> client
  uint64_t ping_client_time{100};
  uint64_t pong_server_time{123};
  uint64_t pong_client_time{100};

  // setup our ping/pong packets
  TspPing ping{.version = 1, .message_id = 1, .client_time = ping_client_time};
  TspPong pong{ping, pong_server_time};

  // WHEN we update statistics
  client.UpdateStatistics(pong_client_time, ping, pong);

  // THEN the statistics will reflect the expected 23ms offset
  EXPECT_EQ(23, client.GetMetadata().offset);
  EXPECT_EQ(0, client.GetMetadata().rtt2);
  EXPECT_EQ(1u, client.GetMetadata().pongsReceived);
  EXPECT_EQ(pong_client_time, client.GetMetadata().lastPongTime);
}

TEST(TimeSyncClientTest, CalculateBoth) {
  using namespace wpi::tsp;
  using namespace std::chrono_literals;

  // GIVEN a fresh client
  TimeSyncClient client{"127.0.0.1", 5812, 100ms};

  // AND a ping-pong sent with no delay
  // client -> server -> client
  int64_t offset{-234};
  int64_t network_latency{23};

  uint64_t ping_client_time{100};
  uint64_t pong_server_time{ping_client_time + offset + network_latency};
  uint64_t pong_client_time{ping_client_time + 2 * network_latency};

  // setup our ping/pong packets
  TspPing ping{.version = 1, .message_id = 1, .client_time = ping_client_time};
  TspPong pong{ping, pong_server_time};

  // WHEN we update statistics
  client.UpdateStatistics(pong_client_time, ping, pong);

  // THEN the statistics will reflect the expected latency and RTT
  EXPECT_EQ(offset, client.GetMetadata().offset);
  EXPECT_EQ(network_latency * 2, client.GetMetadata().rtt2);
  EXPECT_EQ(1u, client.GetMetadata().pongsReceived);
  EXPECT_EQ(pong_client_time, client.GetMetadata().lastPongTime);
}