#  Copyright (c) 2016 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.

"""Displays statistics and plots graphs from RTC protobuf dump."""

from __future__ import division
from __future__ import print_function

import collections
import sys

import matplotlib.pyplot as plt
import numpy

import misc
import pb_parse


class RTPStatistics(object):
  """Has methods for calculating and plotting RTP stream statistics."""

  BANDWIDTH_SMOOTHING_WINDOW_SIZE = 10

  def __init__(self, data_points):
    """Initializes object with data_points and computes simple statistics.

    Computes percentages of number of packets and packet sizes by
    SSRC.

    Args:
        data_points: list of pb_parse.DataPoints on which statistics are
            calculated.

    """

    self.data_points = data_points
    self.ssrc_frequencies = misc.normalize_counter(
        collections.Counter([pt.ssrc for pt in self.data_points]))
    self.ssrc_size_table = misc.ssrc_normalized_size_table(self.data_points)
    self.bandwidth_kbps = None
    self.smooth_bw_kbps = None

  def print_ssrc_info(self, ssrc_id, ssrc):
    """Prints packet and size statistics for a given SSRC.

    Args:
        ssrc_id: textual identifier of SSRC printed beside statistics for it.
        ssrc: SSRC by which to filter data and display statistics
    """
    filtered_ssrc = [point for point in self.data_points if point.ssrc
                     == ssrc]
    payloads = misc.normalize_counter(
        collections.Counter([point.payload_type for point in
                             filtered_ssrc]))

    payload_info = "payload type(s): {}".format(
        ", ".join(str(payload) for payload in  payloads))
    print("{} 0x{:x} {}, {:.2f}% packets, {:.2f}% data".format(
        ssrc_id, ssrc, payload_info, self.ssrc_frequencies[ssrc] * 100,
        self.ssrc_size_table[ssrc] * 100))
    print("  packet sizes:")
    (bin_counts, bin_bounds) = numpy.histogram([point.size for point in
                                                filtered_ssrc], bins=5,
                                               density=False)
    bin_proportions = bin_counts / sum(bin_counts)
    print("\n".join([
        " {:.1f} - {:.1f}: {:.2f}%".format(bin_bounds[i], bin_bounds[i + 1],
                                           bin_proportions[i] * 100)
        for i in range(len(bin_proportions))
    ]))

  def choose_ssrc(self):
    """Queries user for SSRC."""

    if len(self.ssrc_frequencies) == 1:
      chosen_ssrc = self.ssrc_frequencies[0][-1]
      self.print_ssrc_info("", chosen_ssrc)
      return chosen_ssrc

    for (i, ssrc) in enumerate(self.ssrc_frequencies):
      self.print_ssrc_info(i, ssrc)

    while True:
      chosen_index = int(misc.get_input("choose one> "))
      if 0 <= chosen_index < len(self.ssrc_frequencies):
        return list(self.ssrc_frequencies)[chosen_index]
      else:
        print("Invalid index!")

  def filter_ssrc(self, chosen_ssrc):
    """Filters and wraps data points.

    Removes data points with `ssrc != chosen_ssrc`. Unwraps sequence
    numbers and timestamps for the chosen selection.
    """
    self.data_points = [point for point in self.data_points if
                        point.ssrc == chosen_ssrc]
    unwrapped_sequence_numbers = misc.unwrap(
        [point.sequence_number for point in self.data_points], 2**16 - 1)
    for (data_point, sequence_number) in zip(self.data_points,
                                             unwrapped_sequence_numbers):
      data_point.sequence_number = sequence_number

    unwrapped_timestamps = misc.unwrap([point.timestamp for point in
                                        self.data_points], 2**32 - 1)

    for (data_point, timestamp) in zip(self.data_points,
                                       unwrapped_timestamps):
      data_point.timestamp = timestamp

  def print_sequence_number_statistics(self):
    seq_no_set = set(point.sequence_number for point in
                     self.data_points)
    print("Missing sequence numbers: {} out of {}".format(
        max(seq_no_set) - min(seq_no_set) + 1 - len(seq_no_set),
        len(seq_no_set)
    ))
    print("Duplicated packets: {}".format(len(self.data_points) -
                                          len(seq_no_set)))
    print("Reordered packets: {}".format(
        misc.count_reordered([point.sequence_number for point in
                              self.data_points])))

  def estimate_frequency(self):
    """Estimates frequency and updates data.

    Guesses the most probable frequency by looking at changes in
    timestamps (RFC 3550 section 5.1), calculates clock drifts and
    sending time of packets. Updates `self.data_points` with changes
    in delay and send time.
    """
    delta_timestamp = (self.data_points[-1].timestamp -
                       self.data_points[0].timestamp)
    delta_arr_timestamp = float((self.data_points[-1].arrival_timestamp_ms -
                                 self.data_points[0].arrival_timestamp_ms))
    freq_est = delta_timestamp / delta_arr_timestamp

    freq_vec = [8, 16, 32, 48, 90]
    freq = None
    for f in freq_vec:
      if abs((freq_est - f) / f) < 0.05:
        freq = f

    print("Estimated frequency: {}kHz".format(freq_est))
    if freq is None:
      freq = int(misc.get_input(
          "Frequency could not be guessed. Input frequency (in kHz)> "))
    else:
      print("Guessed frequency: {}kHz".format(freq))

    for point in self.data_points:
      point.real_send_time_ms = (point.timestamp -
                                 self.data_points[0].timestamp) / freq
      point.delay = point.arrival_timestamp_ms -point.real_send_time_ms

  def print_duration_statistics(self):
    """Prints delay, clock drift and bitrate statistics."""

    min_delay = min(point.delay for point in self.data_points)

    for point in self.data_points:
      point.absdelay = point.delay - min_delay

    stream_duration_sender = self.data_points[-1].real_send_time_ms / 1000
    print("Stream duration at sender: {:.1f} seconds".format(
        stream_duration_sender
    ))

    arrival_timestamps_ms = [point.arrival_timestamp_ms for point in
                             self.data_points]
    stream_duration_receiver = (max(arrival_timestamps_ms) -
                                min(arrival_timestamps_ms)) / 1000
    print("Stream duration at receiver: {:.1f} seconds".format(
        stream_duration_receiver
    ))

    print("Clock drift: {:.2f}%".format(
        100 * (stream_duration_receiver / stream_duration_sender - 1)
    ))

    total_size = sum(point.size for point in self.data_points) * 8 / 1000
    print("Send average bitrate: {:.2f} kbps".format(
        total_size / stream_duration_sender))

    print("Receive average bitrate: {:.2f} kbps".format(
        total_size / stream_duration_receiver))

  def remove_reordered(self):
    last = self.data_points[0]
    data_points_ordered = [last]
    for point in self.data_points[1:]:
      if point.sequence_number > last.sequence_number and (
          point.real_send_time_ms > last.real_send_time_ms):
        data_points_ordered.append(point)
        last = point
    self.data_points = data_points_ordered

  def compute_bandwidth(self):
    """Computes bandwidth averaged over several consecutive packets.

    The number of consecutive packets used in the average is
    BANDWIDTH_SMOOTHING_WINDOW_SIZE. Averaging is done with
    numpy.correlate.
    """
    self.bandwidth_kbps = []
    for i in range(len(self.data_points) - 1):
      self.bandwidth_kbps.append(self.data_points[i].size * 8 /
                                 (self.data_points[i +
                                                   1].real_send_time_ms -
                                  self.data_points[i].real_send_time_ms)
                                )
    correlate_filter = (numpy.ones(
        RTPStatistics.BANDWIDTH_SMOOTHING_WINDOW_SIZE) /
                        RTPStatistics.BANDWIDTH_SMOOTHING_WINDOW_SIZE)
    self.smooth_bw_kbps = numpy.correlate(self.bandwidth_kbps, correlate_filter)

  def plot_statistics(self):
    """Plots changes in delay and average bandwidth."""
    plt.figure(1)
    plt.plot([f.real_send_time_ms / 1000 for f in self.data_points],
             [f.absdelay for f in self.data_points])
    plt.xlabel("Send time [s]")
    plt.ylabel("Relative transport delay [ms]")

    plt.figure(2)
    plt.plot([f.real_send_time_ms / 1000 for f in
              self.data_points][:len(self.smooth_bw_kbps)],
             self.smooth_bw_kbps[:len(self.data_points)])
    plt.xlabel("Send time [s]")
    plt.ylabel("Bandwidth [kbps]")

    plt.show()


def main():
  if len(sys.argv) < 2:
    print("Usage: python rtp_analyzer.py <filename of rtc event log>")
    sys.exit(0)

  data_points = pb_parse.parse_protobuf(sys.argv[1])
  rtp_stats = RTPStatistics(data_points)
  chosen_ssrc = rtp_stats.choose_ssrc()
  print("Chosen SSRC: 0X{:X}".format(chosen_ssrc))

  rtp_stats.filter_ssrc(chosen_ssrc)
  print("Statistics:")
  rtp_stats.print_sequence_number_statistics()
  rtp_stats.estimate_frequency()
  rtp_stats.print_duration_statistics()
  rtp_stats.remove_reordered()
  rtp_stats.compute_bandwidth()
  rtp_stats.plot_statistics()

if __name__ == "__main__":
  main()