#!/usr/bin/env python3
# Copyright      2022  Xiaomi Corp.        (authors: Fangjun Kuang)
#
# See ../../../../LICENSE for clarification regarding multiple authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
This script loads ONNX models and uses them to decode waves.
You can use the following command to get the exported models:

./lstm_transducer_stateless2/export.py \
  --exp-dir ./lstm_transducer_stateless2/exp \
  --bpe-model data/lang_bpe_500/bpe.model \
  --epoch 20 \
  --avg 10 \
  --onnx 1

Usage of this script:

./lstm_transducer_stateless2/onnx-streaming-decode.py \
  --encoder-model-filename ./lstm_transducer_stateless2/exp/encoder.onnx \
  --decoder-model-filename ./lstm_transducer_stateless2/exp/decoder.onnx \
  --joiner-model-filename ./lstm_transducer_stateless2/exp/joiner.onnx \
  --joiner-encoder-proj-model-filename ./lstm_transducer_stateless2/exp/joiner_encoder_proj.onnx \
  --joiner-decoder-proj-model-filename ./lstm_transducer_stateless2/exp/joiner_decoder_proj.onnx \
  --bpe-model ./data/lang_bpe_500/bpe.model \
  /path/to/foo.wav \
  /path/to/bar.wav
"""

import argparse
import logging
from typing import List, Optional, Tuple

from icefall import is_module_available

if not is_module_available("onnxruntime"):
    raise ValueError("Please 'pip install onnxruntime' first.")

import onnxruntime as ort
import sentencepiece as spm
import torch
import torchaudio
from kaldifeat import FbankOptions, OnlineFbank, OnlineFeature


def get_args():
    parser = argparse.ArgumentParser(
        formatter_class=argparse.ArgumentDefaultsHelpFormatter
    )

    parser.add_argument(
        "--bpe-model-filename",
        type=str,
        help="Path to bpe.model",
    )

    parser.add_argument(
        "--encoder-model-filename",
        type=str,
        required=True,
        help="Path to the encoder onnx model. ",
    )

    parser.add_argument(
        "--decoder-model-filename",
        type=str,
        required=True,
        help="Path to the decoder onnx model. ",
    )

    parser.add_argument(
        "--joiner-model-filename",
        type=str,
        required=True,
        help="Path to the joiner onnx model. ",
    )

    parser.add_argument(
        "--joiner-encoder-proj-model-filename",
        type=str,
        required=True,
        help="Path to the joiner encoder_proj onnx model. ",
    )

    parser.add_argument(
        "--joiner-decoder-proj-model-filename",
        type=str,
        required=True,
        help="Path to the joiner decoder_proj onnx model. ",
    )

    parser.add_argument(
        "--bpe-model",
        type=str,
        help="""Path to bpe.model.""",
    )

    parser.add_argument(
        "sound_filename",
        type=str,
        help="The input sound file(s) to transcribe. "
        "Supported formats are those supported by torchaudio.load(). "
        "For example, wav and flac are supported. "
        "The sample rate has to be 16kHz.",
    )

    parser.add_argument(
        "--sample-rate",
        type=int,
        default=16000,
        help="The sample rate of the input sound file",
    )

    parser.add_argument(
        "--context-size",
        type=int,
        default=2,
        help="Context size of the decoder model",
    )

    return parser.parse_args()


def read_sound_files(
    filenames: List[str], expected_sample_rate: float
) -> List[torch.Tensor]:
    """Read a list of sound files into a list 1-D float32 torch tensors.
    Args:
      filenames:
        A list of sound filenames.
      expected_sample_rate:
        The expected sample rate of the sound files.
    Returns:
      Return a list of 1-D float32 torch tensors.
    """
    ans = []
    for f in filenames:
        wave, sample_rate = torchaudio.load(f)
        assert (
            sample_rate == expected_sample_rate
        ), f"expected sample rate: {expected_sample_rate}. Given: {sample_rate}"
        # We use only the first channel
        ans.append(wave[0])
    return ans


class Model:
    def __init__(self, args):
        session_opts = ort.SessionOptions()
        session_opts.inter_op_num_threads = 5
        session_opts.intra_op_num_threads = 5
        self.session_opts = session_opts

        self.init_encoder(args)
        self.init_decoder(args)
        self.init_joiner(args)
        self.init_joiner_encoder_proj(args)
        self.init_joiner_decoder_proj(args)

    def init_encoder(self, args):
        self.encoder = ort.InferenceSession(
            args.encoder_model_filename,
            sess_options=self.session_opts,
        )

    def init_decoder(self, args):
        self.decoder = ort.InferenceSession(
            args.decoder_model_filename,
            sess_options=self.session_opts,
        )

    def init_joiner(self, args):
        self.joiner = ort.InferenceSession(
            args.joiner_model_filename,
            sess_options=self.session_opts,
        )

    def init_joiner_encoder_proj(self, args):
        self.joiner_encoder_proj = ort.InferenceSession(
            args.joiner_encoder_proj_model_filename,
            sess_options=self.session_opts,
        )

    def init_joiner_decoder_proj(self, args):
        self.joiner_decoder_proj = ort.InferenceSession(
            args.joiner_decoder_proj_model_filename,
            sess_options=self.session_opts,
        )

    def run_encoder(self, x, h0, c0) -> Tuple[torch.Tensor, torch.Tensor, torch.Tensor]:
        """
        Args:
          x:
            A tensor of shape (N, T, C)
          h0:
            A tensor of shape (num_layers, N, proj_size)
          c0:
            A tensor of shape (num_layers, N, hidden_size)
        Returns:
          Return a tuple containing:
            - encoder_out: A tensor of shape (N, T', C')
            - next_h0: A tensor of shape (num_layers, N, proj_size)
            - next_c0: A tensor of shape (num_layers, N, hidden_size)
        """
        encoder_input_nodes = self.encoder.get_inputs()
        encoder_out_nodes = self.encoder.get_outputs()
        x_lens = torch.tensor([x.size(1)], dtype=torch.int64)

        encoder_out, encoder_out_lens, next_h0, next_c0 = self.encoder.run(
            [
                encoder_out_nodes[0].name,
                encoder_out_nodes[1].name,
                encoder_out_nodes[2].name,
                encoder_out_nodes[3].name,
            ],
            {
                encoder_input_nodes[0].name: x.numpy(),
                encoder_input_nodes[1].name: x_lens.numpy(),
                encoder_input_nodes[2].name: h0.numpy(),
                encoder_input_nodes[3].name: c0.numpy(),
            },
        )
        return (
            torch.from_numpy(encoder_out),
            torch.from_numpy(next_h0),
            torch.from_numpy(next_c0),
        )

    def run_decoder(self, decoder_input: torch.Tensor) -> torch.Tensor:
        """
        Args:
          decoder_input:
            A tensor of shape (N, context_size). Its dtype is torch.int64.
        Returns:
          Return a tensor of shape (N, 1, decoder_out_dim).
        """
        decoder_input_nodes = self.decoder.get_inputs()
        decoder_output_nodes = self.decoder.get_outputs()

        decoder_out = self.decoder.run(
            [decoder_output_nodes[0].name],
            {
                decoder_input_nodes[0].name: decoder_input.numpy(),
            },
        )[0]

        return self.run_joiner_decoder_proj(torch.from_numpy(decoder_out).squeeze(1))

    def run_joiner(
        self,
        projected_encoder_out: torch.Tensor,
        projected_decoder_out: torch.Tensor,
    ) -> torch.Tensor:
        """
        Args:
          projected_encoder_out:
            A tensor of shape (N, joiner_dim)
          projected_decoder_out:
            A tensor of shape (N, joiner_dim)
        Returns:
          Return a tensor of shape (N, vocab_size)
        """
        joiner_input_nodes = self.joiner.get_inputs()
        joiner_output_nodes = self.joiner.get_outputs()

        logits = self.joiner.run(
            [joiner_output_nodes[0].name],
            {
                joiner_input_nodes[0].name: projected_encoder_out.numpy(),
                joiner_input_nodes[1].name: projected_decoder_out.numpy(),
            },
        )[0]

        return torch.from_numpy(logits)

    def run_joiner_encoder_proj(
        self,
        encoder_out: torch.Tensor,
    ) -> torch.Tensor:
        """
        Args:
          encoder_out:
            A tensor of shape (N, encoder_out_dim)
        Returns:
            A tensor of shape (N, joiner_dim)
        """

        projected_encoder_out = self.joiner_encoder_proj.run(
            [self.joiner_encoder_proj.get_outputs()[0].name],
            {self.joiner_encoder_proj.get_inputs()[0].name: encoder_out.numpy()},
        )[0]

        return torch.from_numpy(projected_encoder_out)

    def run_joiner_decoder_proj(
        self,
        decoder_out: torch.Tensor,
    ) -> torch.Tensor:
        """
        Args:
          decoder_out:
            A tensor of shape (N, decoder_out_dim)
        Returns:
            A tensor of shape (N, joiner_dim)
        """

        projected_decoder_out = self.joiner_decoder_proj.run(
            [self.joiner_decoder_proj.get_outputs()[0].name],
            {self.joiner_decoder_proj.get_inputs()[0].name: decoder_out.numpy()},
        )[0]

        return torch.from_numpy(projected_decoder_out)


def create_streaming_feature_extractor() -> OnlineFeature:
    """Create a CPU streaming feature extractor.

    At present, we assume it returns a fbank feature extractor with
    fixed options. In the future, we will support passing in the options
    from outside.

    Returns:
      Return a CPU streaming feature extractor.
    """
    opts = FbankOptions()
    opts.device = "cpu"
    opts.frame_opts.dither = 0
    opts.frame_opts.snip_edges = False
    opts.frame_opts.samp_freq = 16000
    opts.mel_opts.num_bins = 80
    return OnlineFbank(opts)


def greedy_search(
    model: Model,
    encoder_out: torch.Tensor,
    decoder_out: Optional[torch.Tensor] = None,
    hyp: Optional[List[int]] = None,
):
    assert encoder_out.ndim == 2
    assert encoder_out.shape[0] == 1, "TODO: support batch_size > 1"
    context_size = 2
    blank_id = 0

    if decoder_out is None:
        assert hyp is None, hyp
        hyp = [blank_id] * context_size
        decoder_input = torch.tensor([hyp], dtype=torch.int64)  # (1, context_size)
        decoder_out = model.run_decoder(decoder_input)
    else:
        assert decoder_out.shape[0] == 1
        assert hyp is not None, hyp

    projected_encoder_out = model.run_joiner_encoder_proj(encoder_out)

    joiner_out = model.run_joiner(projected_encoder_out, decoder_out)
    y = joiner_out.squeeze(0).argmax(dim=0).item()

    if y != blank_id:
        hyp.append(y)
        decoder_input = hyp[-context_size:]
        decoder_input = torch.tensor([decoder_input], dtype=torch.int64)
        decoder_out = model.run_decoder(decoder_input)

    return hyp, decoder_out


def main():
    args = get_args()
    logging.info(vars(args))

    model = Model(args)

    sound_file = args.sound_filename
    sample_rate = 16000

    sp = spm.SentencePieceProcessor()
    sp.load(args.bpe_model_filename)

    logging.info("Constructing Fbank computer")
    online_fbank = create_streaming_feature_extractor()

    logging.info(f"Reading sound files: {sound_file}")
    wave_samples = read_sound_files(
        filenames=[sound_file],
        expected_sample_rate=sample_rate,
    )[0]
    logging.info(wave_samples.shape)

    num_encoder_layers = 12
    batch_size = 1
    d_model = 512
    rnn_hidden_size = 1024

    h0 = torch.zeros(num_encoder_layers, batch_size, d_model)
    c0 = torch.zeros(num_encoder_layers, batch_size, rnn_hidden_size)

    hyp = None
    decoder_out = None

    num_processed_frames = 0
    segment = 9
    offset = 4

    chunk = 3200  # 0.2 second

    start = 0
    while start < wave_samples.numel():
        end = min(start + chunk, wave_samples.numel())
        samples = wave_samples[start:end]
        start += chunk

        online_fbank.accept_waveform(
            sampling_rate=sample_rate,
            waveform=samples,
        )
        while online_fbank.num_frames_ready - num_processed_frames >= segment:
            frames = []
            for i in range(segment):
                frames.append(online_fbank.get_frame(num_processed_frames + i))

            num_processed_frames += offset
            frames = torch.cat(frames, dim=0).unsqueeze(0)
            encoder_out, h0, c0 = model.run_encoder(frames, h0, c0)
            hyp, decoder_out = greedy_search(
                model, encoder_out.squeeze(0), decoder_out, hyp
            )
    online_fbank.accept_waveform(
        sampling_rate=sample_rate, waveform=torch.zeros(5000, dtype=torch.float)
    )

    online_fbank.input_finished()
    while online_fbank.num_frames_ready - num_processed_frames >= segment:
        frames = []
        for i in range(segment):
            frames.append(online_fbank.get_frame(num_processed_frames + i))
        num_processed_frames += offset
        frames = torch.cat(frames, dim=0).unsqueeze(0)
        encoder_out, h0, c0 = model.run_encoder(frames, h0, c0)
        hyp, decoder_out = greedy_search(
            model, encoder_out.squeeze(0), decoder_out, hyp
        )

    context_size = 2

    logging.info(sound_file)
    logging.info(sp.decode(hyp[context_size:]))


if __name__ == "__main__":
    formatter = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"

    logging.basicConfig(format=formatter, level=logging.INFO)

    main()