# Copyright (c) 2017 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.
"""Extraction of annotations from audio files.
"""

from __future__ import division
import logging
import os
import shutil
import struct
import subprocess
import sys
import tempfile

try:
    import numpy as np
except ImportError:
    logging.critical('Cannot import the third-party Python package numpy')
    sys.exit(1)

from . import external_vad
from . import exceptions
from . import signal_processing


class AudioAnnotationsExtractor(object):
    """Extracts annotations from audio files.
  """

    class VadType(object):
        ENERGY_THRESHOLD = 1  # TODO(alessiob): Consider switching to P56 standard.
        WEBRTC_COMMON_AUDIO = 2  # common_audio/vad/include/vad.h
        WEBRTC_APM = 4  # modules/audio_processing/vad/vad.h

        def __init__(self, value):
            if (not isinstance(value, int)) or not 0 <= value <= 7:
                raise exceptions.InitializationException('Invalid vad type: ' +
                                                         value)
            self._value = value

        def Contains(self, vad_type):
            return self._value | vad_type == self._value

        def __str__(self):
            vads = []
            if self.Contains(self.ENERGY_THRESHOLD):
                vads.append("energy")
            if self.Contains(self.WEBRTC_COMMON_AUDIO):
                vads.append("common_audio")
            if self.Contains(self.WEBRTC_APM):
                vads.append("apm")
            return "VadType({})".format(", ".join(vads))

    _OUTPUT_FILENAME_TEMPLATE = '{}annotations.npz'

    # Level estimation params.
    _ONE_DB_REDUCTION = np.power(10.0, -1.0 / 20.0)
    _LEVEL_FRAME_SIZE_MS = 1.0
    # The time constants in ms indicate the time it takes for the level estimate
    # to go down/up by 1 db if the signal is zero.
    _LEVEL_ATTACK_MS = 5.0
    _LEVEL_DECAY_MS = 20.0

    # VAD params.
    _VAD_THRESHOLD = 1
    _VAD_WEBRTC_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                                    os.pardir, os.pardir)
    _VAD_WEBRTC_COMMON_AUDIO_PATH = os.path.join(_VAD_WEBRTC_PATH, 'vad')

    _VAD_WEBRTC_APM_PATH = os.path.join(_VAD_WEBRTC_PATH, 'apm_vad')

    def __init__(self, vad_type, external_vads=None):
        self._signal = None
        self._level = None
        self._level_frame_size = None
        self._common_audio_vad = None
        self._energy_vad = None
        self._apm_vad_probs = None
        self._apm_vad_rms = None
        self._vad_frame_size = None
        self._vad_frame_size_ms = None
        self._c_attack = None
        self._c_decay = None

        self._vad_type = self.VadType(vad_type)
        logging.info('VADs used for annotations: ' + str(self._vad_type))

        if external_vads is None:
            external_vads = {}
        self._external_vads = external_vads

        assert len(self._external_vads) == len(external_vads), (
            'The external VAD names must be unique.')
        for vad in external_vads.values():
            if not isinstance(vad, external_vad.ExternalVad):
                raise exceptions.InitializationException('Invalid vad type: ' +
                                                         str(type(vad)))
            logging.info('External VAD used for annotation: ' + str(vad.name))

        assert os.path.exists(self._VAD_WEBRTC_COMMON_AUDIO_PATH), \
          self._VAD_WEBRTC_COMMON_AUDIO_PATH
        assert os.path.exists(self._VAD_WEBRTC_APM_PATH), \
          self._VAD_WEBRTC_APM_PATH

    @classmethod
    def GetOutputFileNameTemplate(cls):
        return cls._OUTPUT_FILENAME_TEMPLATE

    def GetLevel(self):
        return self._level

    def GetLevelFrameSize(self):
        return self._level_frame_size

    @classmethod
    def GetLevelFrameSizeMs(cls):
        return cls._LEVEL_FRAME_SIZE_MS

    def GetVadOutput(self, vad_type):
        if vad_type == self.VadType.ENERGY_THRESHOLD:
            return self._energy_vad
        elif vad_type == self.VadType.WEBRTC_COMMON_AUDIO:
            return self._common_audio_vad
        elif vad_type == self.VadType.WEBRTC_APM:
            return (self._apm_vad_probs, self._apm_vad_rms)
        else:
            raise exceptions.InitializationException('Invalid vad type: ' +
                                                     vad_type)

    def GetVadFrameSize(self):
        return self._vad_frame_size

    def GetVadFrameSizeMs(self):
        return self._vad_frame_size_ms

    def Extract(self, filepath):
        # Load signal.
        self._signal = signal_processing.SignalProcessingUtils.LoadWav(
            filepath)
        if self._signal.channels != 1:
            raise NotImplementedError(
                'Multiple-channel annotations not implemented')

        # Level estimation params.
        self._level_frame_size = int(self._signal.frame_rate / 1000 *
                                     (self._LEVEL_FRAME_SIZE_MS))
        self._c_attack = 0.0 if self._LEVEL_ATTACK_MS == 0 else (
            self._ONE_DB_REDUCTION**(self._LEVEL_FRAME_SIZE_MS /
                                     self._LEVEL_ATTACK_MS))
        self._c_decay = 0.0 if self._LEVEL_DECAY_MS == 0 else (
            self._ONE_DB_REDUCTION**(self._LEVEL_FRAME_SIZE_MS /
                                     self._LEVEL_DECAY_MS))

        # Compute level.
        self._LevelEstimation()

        # Ideal VAD output, it requires clean speech with high SNR as input.
        if self._vad_type.Contains(self.VadType.ENERGY_THRESHOLD):
            # Naive VAD based on level thresholding.
            vad_threshold = np.percentile(self._level, self._VAD_THRESHOLD)
            self._energy_vad = np.uint8(self._level > vad_threshold)
            self._vad_frame_size = self._level_frame_size
            self._vad_frame_size_ms = self._LEVEL_FRAME_SIZE_MS
        if self._vad_type.Contains(self.VadType.WEBRTC_COMMON_AUDIO):
            # WebRTC common_audio/ VAD.
            self._RunWebRtcCommonAudioVad(filepath, self._signal.frame_rate)
        if self._vad_type.Contains(self.VadType.WEBRTC_APM):
            # WebRTC modules/audio_processing/ VAD.
            self._RunWebRtcApmVad(filepath)
        for extvad_name in self._external_vads:
            self._external_vads[extvad_name].Run(filepath)

    def Save(self, output_path, annotation_name=""):
        ext_kwargs = {
            'extvad_conf-' + ext_vad:
            self._external_vads[ext_vad].GetVadOutput()
            for ext_vad in self._external_vads
        }
        np.savez_compressed(file=os.path.join(
            output_path,
            self.GetOutputFileNameTemplate().format(annotation_name)),
                            level=self._level,
                            level_frame_size=self._level_frame_size,
                            level_frame_size_ms=self._LEVEL_FRAME_SIZE_MS,
                            vad_output=self._common_audio_vad,
                            vad_energy_output=self._energy_vad,
                            vad_frame_size=self._vad_frame_size,
                            vad_frame_size_ms=self._vad_frame_size_ms,
                            vad_probs=self._apm_vad_probs,
                            vad_rms=self._apm_vad_rms,
                            **ext_kwargs)

    def _LevelEstimation(self):
        # Read samples.
        samples = signal_processing.SignalProcessingUtils.AudioSegmentToRawData(
            self._signal).astype(np.float32) / 32768.0
        num_frames = len(samples) // self._level_frame_size
        num_samples = num_frames * self._level_frame_size

        # Envelope.
        self._level = np.max(np.reshape(np.abs(samples[:num_samples]),
                                        (num_frames, self._level_frame_size)),
                             axis=1)
        assert len(self._level) == num_frames

        # Envelope smoothing.
        smooth = lambda curr, prev, k: (1 - k) * curr + k * prev
        self._level[0] = smooth(self._level[0], 0.0, self._c_attack)
        for i in range(1, num_frames):
            self._level[i] = smooth(
                self._level[i], self._level[i - 1], self._c_attack if
                (self._level[i] > self._level[i - 1]) else self._c_decay)

    def _RunWebRtcCommonAudioVad(self, wav_file_path, sample_rate):
        self._common_audio_vad = None
        self._vad_frame_size = None

        # Create temporary output path.
        tmp_path = tempfile.mkdtemp()
        output_file_path = os.path.join(
            tmp_path,
            os.path.split(wav_file_path)[1] + '_vad.tmp')

        # Call WebRTC VAD.
        try:
            subprocess.call([
                self._VAD_WEBRTC_COMMON_AUDIO_PATH, '-i', wav_file_path, '-o',
                output_file_path
            ],
                            cwd=self._VAD_WEBRTC_PATH)

            # Read bytes.
            with open(output_file_path, 'rb') as f:
                raw_data = f.read()

            # Parse side information.
            self._vad_frame_size_ms = struct.unpack('B', raw_data[0])[0]
            self._vad_frame_size = self._vad_frame_size_ms * sample_rate / 1000
            assert self._vad_frame_size_ms in [10, 20, 30]
            extra_bits = struct.unpack('B', raw_data[-1])[0]
            assert 0 <= extra_bits <= 8

            # Init VAD vector.
            num_bytes = len(raw_data)
            num_frames = 8 * (num_bytes -
                              2) - extra_bits  # 8 frames for each byte.
            self._common_audio_vad = np.zeros(num_frames, np.uint8)

            # Read VAD decisions.
            for i, byte in enumerate(raw_data[1:-1]):
                byte = struct.unpack('B', byte)[0]
                for j in range(8 if i < num_bytes - 3 else (8 - extra_bits)):
                    self._common_audio_vad[i * 8 + j] = int(byte & 1)
                    byte = byte >> 1
        except Exception as e:
            logging.error('Error while running the WebRTC VAD (' + e.message +
                          ')')
        finally:
            if os.path.exists(tmp_path):
                shutil.rmtree(tmp_path)

    def _RunWebRtcApmVad(self, wav_file_path):
        # Create temporary output path.
        tmp_path = tempfile.mkdtemp()
        output_file_path_probs = os.path.join(
            tmp_path,
            os.path.split(wav_file_path)[1] + '_vad_probs.tmp')
        output_file_path_rms = os.path.join(
            tmp_path,
            os.path.split(wav_file_path)[1] + '_vad_rms.tmp')

        # Call WebRTC VAD.
        try:
            subprocess.call([
                self._VAD_WEBRTC_APM_PATH, '-i', wav_file_path, '-o_probs',
                output_file_path_probs, '-o_rms', output_file_path_rms
            ],
                            cwd=self._VAD_WEBRTC_PATH)

            # Parse annotations.
            self._apm_vad_probs = np.fromfile(output_file_path_probs,
                                              np.double)
            self._apm_vad_rms = np.fromfile(output_file_path_rms, np.double)
            assert len(self._apm_vad_rms) == len(self._apm_vad_probs)

        except Exception as e:
            logging.error('Error while running the WebRTC APM VAD (' +
                          e.message + ')')
        finally:
            if os.path.exists(tmp_path):
                shutil.rmtree(tmp_path)