/*
 *  Copyright (c) 2012 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 "system_wrappers/include/rtp_to_ntp_estimator.h"

#include <stddef.h>

#include "rtc_base/random.h"
#include "test/gtest.h"

namespace webrtc {
namespace {
const uint32_t kOneMsInNtpFrac = 4294967;
const uint32_t kOneHourInNtpSec = 60 * 60;
const uint32_t kTimestampTicksPerMs = 90;
}  // namespace

TEST(WrapAroundTests, OldRtcpWrapped_OldRtpTimestamp) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp -= kTimestampTicksPerMs;
  // No wraparound will be detected, since we are not allowed to wrap below 0,
  // but there will be huge rtp timestamp jump, e.g. old_timestamp = 0,
  // new_timestamp = 4294967295, which should be detected.
  EXPECT_FALSE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
}

TEST(WrapAroundTests, OldRtcpWrapped_OldRtpTimestamp_Wraparound_Detected) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0xFFFFFFFE;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += 2 * kOneMsInNtpFrac;
  timestamp += 2 * kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp -= kTimestampTicksPerMs;
  // Expected to fail since the older RTCP has a smaller RTP timestamp than the
  // newer (old:10, new:4294967206).
  EXPECT_FALSE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
}

TEST(WrapAroundTests, NewRtcpWrapped) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0xFFFFFFFF;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  int64_t timestamp_ms = -1;
  EXPECT_TRUE(estimator.Estimate(0xFFFFFFFF, &timestamp_ms));
  // Since this RTP packet has the same timestamp as the RTCP packet constructed
  // at time 0 it should be mapped to 0 as well.
  EXPECT_EQ(0, timestamp_ms);
}

TEST(WrapAroundTests, RtpWrapped) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0xFFFFFFFF - 2 * kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));

  int64_t timestamp_ms = -1;
  EXPECT_TRUE(
      estimator.Estimate(0xFFFFFFFF - 2 * kTimestampTicksPerMs, &timestamp_ms));
  // Since this RTP packet has the same timestamp as the RTCP packet constructed
  // at time 0 it should be mapped to 0 as well.
  EXPECT_EQ(0, timestamp_ms);
  // Two kTimestampTicksPerMs advanced.
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
  EXPECT_EQ(2, timestamp_ms);
  // Wrapped rtp.
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
  EXPECT_EQ(3, timestamp_ms);
}

TEST(WrapAroundTests, OldRtp_RtcpsWrapped) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0xFFFFFFFF;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  timestamp -= 2 * kTimestampTicksPerMs;
  int64_t timestamp_ms = 0xFFFFFFFF;
  EXPECT_FALSE(estimator.Estimate(timestamp, &timestamp_ms));
}

TEST(WrapAroundTests, OldRtp_NewRtcpWrapped) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0xFFFFFFFF;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  timestamp -= kTimestampTicksPerMs;
  int64_t timestamp_ms = -1;
  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
  // Constructed at the same time as the first RTCP and should therefore be
  // mapped to zero.
  EXPECT_EQ(0, timestamp_ms);
}

TEST(WrapAroundTests, GracefullyHandleRtpJump) {
  RtpToNtpEstimator estimator;
  bool new_sr;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 1;
  uint32_t timestamp = 0;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp -= kTimestampTicksPerMs;
  int64_t timestamp_ms = -1;
  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
  // Constructed at the same time as the first RTCP and should therefore be
  // mapped to zero.
  EXPECT_EQ(0, timestamp_ms);

  timestamp -= 0xFFFFF;
  for (int i = 0; i < RtpToNtpEstimator::kMaxInvalidSamples - 1; ++i) {
    EXPECT_FALSE(
        estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
    ntp_frac += kOneMsInNtpFrac;
    timestamp += kTimestampTicksPerMs;
  }
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;

  timestamp_ms = -1;
  EXPECT_TRUE(estimator.Estimate(timestamp, &timestamp_ms));
  // 6 milliseconds has passed since the start of the test.
  EXPECT_EQ(6, timestamp_ms);
}

TEST(UpdateRtcpMeasurementTests, FailsForZeroNtp) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 0;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_FALSE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_FALSE(new_sr);
}

TEST(UpdateRtcpMeasurementTests, FailsForEqualNtp) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 699925050;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  // Ntp time already added, list not updated.
  ++timestamp;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_FALSE(new_sr);
}

TEST(UpdateRtcpMeasurementTests, FailsForOldNtp) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 1;
  uint32_t ntp_frac = 699925050;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  // Old ntp time, list not updated.
  ntp_frac -= kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_FALSE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
}

TEST(UpdateRtcpMeasurementTests, FailsForTooNewNtp) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 1;
  uint32_t ntp_frac = 699925050;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  // Ntp time from far future, list not updated.
  ntp_sec += kOneHourInNtpSec * 2;
  timestamp += kTimestampTicksPerMs * 10;
  EXPECT_FALSE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
}

TEST(UpdateRtcpMeasurementTests, FailsForEqualTimestamp) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 2;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  // Timestamp already added, list not updated.
  ++ntp_frac;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_FALSE(new_sr);
}

TEST(UpdateRtcpMeasurementTests, FailsForOldRtpTimestamp) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 2;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  // Old timestamp, list not updated.
  ntp_frac += kOneMsInNtpFrac;
  timestamp -= kTimestampTicksPerMs;
  EXPECT_FALSE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_FALSE(new_sr);
}

TEST(UpdateRtcpMeasurementTests, VerifyParameters) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 1;
  uint32_t ntp_frac = 2;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  EXPECT_FALSE(estimator.params());
  // Add second report, parameters should be calculated.
  ntp_frac += kOneMsInNtpFrac;
  timestamp += kTimestampTicksPerMs;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(estimator.params());
  EXPECT_DOUBLE_EQ(90.0, estimator.params()->frequency_khz);
  EXPECT_NE(0.0, estimator.params()->offset_ms);
}

TEST(RtpToNtpTests, FailsForNoParameters) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 1;
  uint32_t ntp_frac = 2;
  uint32_t timestamp = 0x12345678;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);
  // Parameters are not calculated, conversion of RTP to NTP time should fail.
  EXPECT_FALSE(estimator.params());
  int64_t timestamp_ms = -1;
  EXPECT_FALSE(estimator.Estimate(timestamp, &timestamp_ms));
}

TEST(RtpToNtpTests, AveragesErrorOut) {
  RtpToNtpEstimator estimator;
  uint32_t ntp_sec = 1;
  uint32_t ntp_frac = 90000000;  // More than 1 ms.
  uint32_t timestamp = 0x12345678;
  const int kNtpSecStep = 1;  // 1 second.
  const int kRtpTicksPerMs = 90;
  const int kRtpStep = kRtpTicksPerMs * 1000;
  bool new_sr;
  EXPECT_TRUE(
      estimator.UpdateMeasurements(ntp_sec, ntp_frac, timestamp, &new_sr));
  EXPECT_TRUE(new_sr);

  Random rand(1123536L);
  for (size_t i = 0; i < 1000; i++) {
    // Advance both timestamps by exactly 1 second.
    ntp_sec += kNtpSecStep;
    timestamp += kRtpStep;
    // Add upto 1ms of errors to NTP and RTP timestamps passed to estimator.
    EXPECT_TRUE(estimator.UpdateMeasurements(
        ntp_sec,
        ntp_frac + rand.Rand(-static_cast<int>(kOneMsInNtpFrac),
                             static_cast<int>(kOneMsInNtpFrac)),
        timestamp + rand.Rand(-kRtpTicksPerMs, kRtpTicksPerMs), &new_sr));
    EXPECT_TRUE(new_sr);

    int64_t estimated_ntp_ms;
    EXPECT_TRUE(estimator.Estimate(timestamp, &estimated_ntp_ms));
    // Allow upto 2 ms of error.
    EXPECT_NEAR(NtpTime(ntp_sec, ntp_frac).ToMs(), estimated_ntp_ms, 2);
  }
}

}  // namespace webrtc