/*
 *  Copyright (c) 2018 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.
 */

#ifndef MODULES_RTP_RTCP_INCLUDE_RTCP_STATISTICS_H_
#define MODULES_RTP_RTCP_INCLUDE_RTCP_STATISTICS_H_

#include <stdint.h>

#include "absl/strings/string_view.h"

namespace webrtc {

// Statistics for an RTCP channel
struct RtcpStatistics {
  uint8_t fraction_lost = 0;
  int32_t packets_lost = 0;  // Defined as a 24 bit signed integer in RTCP
  uint32_t extended_highest_sequence_number = 0;
  uint32_t jitter = 0;
};

class RtcpStatisticsCallback {
 public:
  virtual ~RtcpStatisticsCallback() {}

  virtual void StatisticsUpdated(const RtcpStatistics& statistics,
                                 uint32_t ssrc) = 0;
};

// Statistics for RTCP packet types.
struct RtcpPacketTypeCounter {
  RtcpPacketTypeCounter()
      : first_packet_time_ms(-1),
        nack_packets(0),
        fir_packets(0),
        pli_packets(0),
        nack_requests(0),
        unique_nack_requests(0) {}

  void Add(const RtcpPacketTypeCounter& other) {
    nack_packets += other.nack_packets;
    fir_packets += other.fir_packets;
    pli_packets += other.pli_packets;
    nack_requests += other.nack_requests;
    unique_nack_requests += other.unique_nack_requests;
    if (other.first_packet_time_ms != -1 &&
        (other.first_packet_time_ms < first_packet_time_ms ||
         first_packet_time_ms == -1)) {
      // Use oldest time.
      first_packet_time_ms = other.first_packet_time_ms;
    }
  }

  void Subtract(const RtcpPacketTypeCounter& other) {
    nack_packets -= other.nack_packets;
    fir_packets -= other.fir_packets;
    pli_packets -= other.pli_packets;
    nack_requests -= other.nack_requests;
    unique_nack_requests -= other.unique_nack_requests;
    if (other.first_packet_time_ms != -1 &&
        (other.first_packet_time_ms > first_packet_time_ms ||
         first_packet_time_ms == -1)) {
      // Use youngest time.
      first_packet_time_ms = other.first_packet_time_ms;
    }
  }

  int64_t TimeSinceFirstPacketInMs(int64_t now_ms) const {
    return (first_packet_time_ms == -1) ? -1 : (now_ms - first_packet_time_ms);
  }

  int UniqueNackRequestsInPercent() const {
    if (nack_requests == 0) {
      return 0;
    }
    return static_cast<int>((unique_nack_requests * 100.0f / nack_requests) +
                            0.5f);
  }

  int64_t first_packet_time_ms;   // Time when first packet is sent/received.
  uint32_t nack_packets;          // Number of RTCP NACK packets.
  uint32_t fir_packets;           // Number of RTCP FIR packets.
  uint32_t pli_packets;           // Number of RTCP PLI packets.
  uint32_t nack_requests;         // Number of NACKed RTP packets.
  uint32_t unique_nack_requests;  // Number of unique NACKed RTP packets.
};

class RtcpPacketTypeCounterObserver {
 public:
  virtual ~RtcpPacketTypeCounterObserver() {}
  virtual void RtcpPacketTypesCounterUpdated(
      uint32_t ssrc,
      const RtcpPacketTypeCounter& packet_counter) = 0;
};

// Invoked for each cname passed in RTCP SDES blocks.
class RtcpCnameCallback {
 public:
  virtual ~RtcpCnameCallback() = default;

  virtual void OnCname(uint32_t ssrc, absl::string_view cname) = 0;
};

}  // namespace webrtc
#endif  // MODULES_RTP_RTCP_INCLUDE_RTCP_STATISTICS_H_