#!/usr/bin/env python3
#
# Copyright (c)  2023  Xiaomi Corporation

"""
This file demonstrates how to use sherpa-onnx Python APIs
with VAD and non-streaming ASR models for speech recognition
from a microphone.

Note that you need a non-streaming model for this script.

(1) For paraformer

    ./python-api-examples/vad-with-non-streaming-asr.py  \
      --silero-vad-model=/path/to/silero_vad.onnx \
      --tokens=/path/to/tokens.txt \
      --paraformer=/path/to/paraformer.onnx \
      --num-threads=2 \
      --decoding-method=greedy_search \
      --debug=false \
      --sample-rate=16000 \
      --feature-dim=80

(2) For transducer models from icefall

    ./python-api-examples/vad-with-non-streaming-asr.py  \
      --silero-vad-model=/path/to/silero_vad.onnx \
      --tokens=/path/to/tokens.txt \
      --encoder=/path/to/encoder.onnx \
      --decoder=/path/to/decoder.onnx \
      --joiner=/path/to/joiner.onnx \
      --num-threads=2 \
      --decoding-method=greedy_search \
      --debug=false \
      --sample-rate=16000 \
      --feature-dim=80

(3) For Whisper models

./python-api-examples/vad-with-non-streaming-asr.py  \
  --silero-vad-model=/path/to/silero_vad.onnx \
  --whisper-encoder=./sherpa-onnx-whisper-base.en/base.en-encoder.int8.onnx \
  --whisper-decoder=./sherpa-onnx-whisper-base.en/base.en-decoder.int8.onnx \
  --tokens=./sherpa-onnx-whisper-base.en/base.en-tokens.txt \
  --whisper-task=transcribe \
  --num-threads=2

Please refer to
https://k2-fsa.github.io/sherpa/onnx/index.html
to install sherpa-onnx and to download non-streaming pre-trained models
used in this file.

Please visit
https://github.com/snakers4/silero-vad/blob/master/files/silero_vad.onnx
to download silero_vad.onnx

For instance,

wget https://github.com/snakers4/silero-vad/raw/master/files/silero_vad.onnx
"""
import argparse
import sys
from pathlib import Path

import numpy as np

try:
    import sounddevice as sd
except ImportError:
    print("Please install sounddevice first. You can use")
    print()
    print("  pip install sounddevice")
    print()
    print("to install it")
    sys.exit(-1)

import sherpa_onnx


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

    parser.add_argument(
        "--silero-vad-model",
        type=str,
        required=True,
        help="Path to silero_vad.onnx",
    )

    parser.add_argument(
        "--tokens",
        type=str,
        help="Path to tokens.txt",
    )

    parser.add_argument(
        "--encoder",
        default="",
        type=str,
        help="Path to the transducer encoder model",
    )

    parser.add_argument(
        "--decoder",
        default="",
        type=str,
        help="Path to the transducer decoder model",
    )

    parser.add_argument(
        "--joiner",
        default="",
        type=str,
        help="Path to the transducer joiner model",
    )

    parser.add_argument(
        "--paraformer",
        default="",
        type=str,
        help="Path to the model.onnx from Paraformer",
    )

    parser.add_argument(
        "--num-threads",
        type=int,
        default=1,
        help="Number of threads for neural network computation",
    )

    parser.add_argument(
        "--whisper-encoder",
        default="",
        type=str,
        help="Path to whisper encoder model",
    )

    parser.add_argument(
        "--whisper-decoder",
        default="",
        type=str,
        help="Path to whisper decoder model",
    )

    parser.add_argument(
        "--whisper-language",
        default="",
        type=str,
        help="""It specifies the spoken language in the input file.
        Example values: en, fr, de, zh, jp.
        Available languages for multilingual models can be found at
        https://github.com/openai/whisper/blob/main/whisper/tokenizer.py#L10
        If not specified, we infer the language from the input audio file.
        """,
    )

    parser.add_argument(
        "--whisper-task",
        default="transcribe",
        choices=["transcribe", "translate"],
        type=str,
        help="""For multilingual models, if you specify translate, the output
        will be in English.
        """,
    )

    parser.add_argument(
        "--whisper-tail-paddings",
        default=-1,
        type=int,
        help="""Number of tail padding frames.
        We have removed the 30-second constraint from whisper, so you need to
        choose the amount of tail padding frames by yourself.
        Use -1 to use a default value for tail padding.
        """,
    )

    parser.add_argument(
        "--blank-penalty",
        type=float,
        default=0.0,
        help="""
        The penalty applied on blank symbol during decoding.
        Note: It is a positive value that would be applied to logits like
        this `logits[:, 0] -= blank_penalty` (suppose logits.shape is
        [batch_size, vocab] and blank id is 0).
        """,
    )

    parser.add_argument(
        "--decoding-method",
        type=str,
        default="greedy_search",
        help="""Valid values are greedy_search and modified_beam_search.
        modified_beam_search is valid only for transducer models.
        """,
    )
    parser.add_argument(
        "--debug",
        type=bool,
        default=False,
        help="True to show debug messages when loading modes.",
    )

    parser.add_argument(
        "--sample-rate",
        type=int,
        default=16000,
        help="""Sample rate of the feature extractor. Must match the one
        expected by the model.""",
    )

    parser.add_argument(
        "--feature-dim",
        type=int,
        default=80,
        help="Feature dimension. Must match the one expected by the model",
    )

    return parser.parse_args()


def assert_file_exists(filename: str):
    assert Path(filename).is_file(), (
        f"{filename} does not exist!\n"
        "Please refer to "
        "https://k2-fsa.github.io/sherpa/onnx/pretrained_models/index.html to download it"
    )


def create_recognizer(args) -> sherpa_onnx.OfflineRecognizer:
    if args.encoder:
        assert len(args.paraformer) == 0, args.paraformer
        assert len(args.whisper_encoder) == 0, args.whisper_encoder
        assert len(args.whisper_decoder) == 0, args.whisper_decoder

        assert_file_exists(args.encoder)
        assert_file_exists(args.decoder)
        assert_file_exists(args.joiner)

        recognizer = sherpa_onnx.OfflineRecognizer.from_transducer(
            encoder=args.encoder,
            decoder=args.decoder,
            joiner=args.joiner,
            tokens=args.tokens,
            num_threads=args.num_threads,
            sample_rate=args.sample_rate,
            feature_dim=args.feature_dim,
            decoding_method=args.decoding_method,
            blank_penalty=args.blank_penalty,
            debug=args.debug,
        )
    elif args.paraformer:
        assert len(args.whisper_encoder) == 0, args.whisper_encoder
        assert len(args.whisper_decoder) == 0, args.whisper_decoder

        assert_file_exists(args.paraformer)

        recognizer = sherpa_onnx.OfflineRecognizer.from_paraformer(
            paraformer=args.paraformer,
            tokens=args.tokens,
            num_threads=args.num_threads,
            sample_rate=args.sample_rate,
            feature_dim=args.feature_dim,
            decoding_method=args.decoding_method,
            debug=args.debug,
        )
    elif args.whisper_encoder:
        assert_file_exists(args.whisper_encoder)
        assert_file_exists(args.whisper_decoder)

        recognizer = sherpa_onnx.OfflineRecognizer.from_whisper(
            encoder=args.whisper_encoder,
            decoder=args.whisper_decoder,
            tokens=args.tokens,
            num_threads=args.num_threads,
            decoding_method=args.decoding_method,
            debug=args.debug,
            language=args.whisper_language,
            task=args.whisper_task,
            tail_paddings=args.whisper_tail_paddings,
        )
    else:
        raise ValueError("Please specify at least one model")

    return recognizer


def main():
    devices = sd.query_devices()
    if len(devices) == 0:
        print("No microphone devices found")
        sys.exit(0)

    print(devices)

    # If you want to select a different input device, please use
    # sd.default.device[0] = xxx
    # where xxx is the device number

    default_input_device_idx = sd.default.device[0]
    print(f'Use default device: {devices[default_input_device_idx]["name"]}')

    args = get_args()
    assert_file_exists(args.tokens)
    assert_file_exists(args.silero_vad_model)

    assert args.num_threads > 0, args.num_threads

    assert (
        args.sample_rate == 16000
    ), f"Only sample rate 16000 is supported.Given: {args.sample_rate}"

    print("Creating recognizer. Please wait...")
    recognizer = create_recognizer(args)

    config = sherpa_onnx.VadModelConfig()
    config.silero_vad.model = args.silero_vad_model
    config.silero_vad.min_silence_duration = 0.25
    config.sample_rate = args.sample_rate

    window_size = config.silero_vad.window_size

    vad = sherpa_onnx.VoiceActivityDetector(config, buffer_size_in_seconds=100)

    samples_per_read = int(0.1 * args.sample_rate)  # 0.1 second = 100 ms

    print("Started! Please speak")

    buffer = []
    texts = []
    with sd.InputStream(channels=1, dtype="float32", samplerate=args.sample_rate) as s:
        while True:
            samples, _ = s.read(samples_per_read)  # a blocking read
            samples = samples.reshape(-1)

            buffer = np.concatenate([buffer, samples])
            while len(buffer) > window_size:
                vad.accept_waveform(buffer[:window_size])
                buffer = buffer[window_size:]

            while not vad.empty():
                stream = recognizer.create_stream()
                stream.accept_waveform(args.sample_rate, vad.front.samples)

                vad.pop()
                recognizer.decode_stream(stream)

                text = stream.result.text.strip().lower()
                if len(text):
                    idx = len(texts)
                    texts.append(text)
                    print(f"{idx}: {text}")


if __name__ == "__main__":
    try:
        main()
    except KeyboardInterrupt:
        print("\nCaught Ctrl + C. Exiting")