# Copyright The Lightning team.
#
# 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.
import os
from functools import lru_cache
from typing import Any, Optional

import numpy as np
import torch
from torch import Tensor

from torchmetrics.utilities import rank_zero_info, rank_zero_warn
from torchmetrics.utilities.imports import _LIBROSA_AVAILABLE, _ONNXRUNTIME_AVAILABLE, _REQUESTS_AVAILABLE

if _LIBROSA_AVAILABLE and _ONNXRUNTIME_AVAILABLE and _REQUESTS_AVAILABLE:
    import librosa
    import onnxruntime as ort
    import requests
    from onnxruntime import InferenceSession
else:
    librosa, ort, requests = None, None, None  # type:ignore

    class InferenceSession:  # type:ignore
        """Dummy InferenceSession."""

        def __init__(self, **kwargs: dict[str, Any]) -> None: ...


__doctest_requires__ = {
    ("deep_noise_suppression_mean_opinion_score", "_load_session"): ["requests", "librosa", "onnxruntime"]
}

SAMPLING_RATE = 16000
INPUT_LENGTH = 9.01
DNSMOS_DIR = "~/.torchmetrics/DNSMOS"


def _prepare_dnsmos(dnsmos_dir: str) -> None:
    """Download required DNSMOS files.

    Args:
        dnsmos_dir: a dir to save the downloaded files. Defaults to "~/.torchmetrics".

    """
    # https://raw.githubusercontent.com/microsoft/DNS-Challenge/master/DNSMOS/DNSMOS/model_v8.onnx
    # https://raw.githubusercontent.com/microsoft/DNS-Challenge/master/DNSMOS/DNSMOS/sig_bak_ovr.onnx
    # https://raw.githubusercontent.com/microsoft/DNS-Challenge/master/DNSMOS/pDNSMOS/sig_bak_ovr.onnx
    url = "https://raw.githubusercontent.com/microsoft/DNS-Challenge/master"
    dnsmos_dir = os.path.expanduser(dnsmos_dir)

    # save to or load from ~/torchmetrics/dnsmos/.
    for file in ["DNSMOS/DNSMOS/model_v8.onnx", "DNSMOS/DNSMOS/sig_bak_ovr.onnx", "DNSMOS/pDNSMOS/sig_bak_ovr.onnx"]:
        saveto = os.path.join(dnsmos_dir, file[7:])
        os.makedirs(os.path.dirname(saveto), exist_ok=True)
        if os.path.exists(saveto):
            # try loading onnx
            try:
                _ = InferenceSession(saveto)
                continue  # skip downloading if succeeded
            except Exception as _:
                os.remove(saveto)
        urlf = f"{url}/{file}"
        rank_zero_info(f"downloading {urlf} to {saveto}")
        myfile = requests.get(urlf)
        with open(saveto, "wb") as f:
            f.write(myfile.content)


def _load_session(
    path: str,
    device: torch.device,
    num_threads: Optional[int] = None,
) -> InferenceSession:
    """Load onnxruntime session.

    Args:
        path: the model path
        device: the device used
        num_threads: the number of threads to use. Defaults to None.

    Returns:
        onnxruntime session

    """
    path = os.path.expanduser(path)
    if not os.path.exists(path):
        _prepare_dnsmos(DNSMOS_DIR)

    opts = ort.SessionOptions()
    if num_threads is not None:
        opts.inter_op_num_threads = num_threads
        opts.intra_op_num_threads = num_threads

    if device.type == "cpu":
        infs = InferenceSession(path, providers=["CPUExecutionProvider"], sess_options=opts)
    elif "CUDAExecutionProvider" in ort.get_available_providers():  # win or linux with cuda
        providers = ["CUDAExecutionProvider", "CPUExecutionProvider"]
        provider_options = [{"device_id": device.index}, {}]
        infs = InferenceSession(path, providers=providers, provider_options=provider_options, sess_options=opts)
    elif "CoreMLExecutionProvider" in ort.get_available_providers():  # macos with coreml
        providers = ["CoreMLExecutionProvider", "CPUExecutionProvider"]
        provider_options = [{"device_id": device.index}, {}]
        infs = InferenceSession(path, providers=providers, provider_options=provider_options, sess_options=opts)
    else:
        infs = InferenceSession(path, providers=["CPUExecutionProvider"], sess_options=opts)

    return infs


_cached_load_session = lru_cache()(_load_session)


def _audio_melspec(
    audio: np.ndarray,
    n_mels: int = 120,
    frame_size: int = 320,
    hop_length: int = 160,
    sr: int = 16000,
    to_db: bool = True,
) -> np.ndarray:
    """Calculate the mel-spectrogram of an audio.

    Args:
        audio: [..., T]
        n_mels: the number of mel-frequencies
        frame_size: stft length
        hop_length: stft hop length
        sr: sample rate of audio
        to_db: convert to dB scale if `True` is given

    Returns:
        mel-spectrogram: [..., num_mel, T']

    """
    shape = audio.shape
    audio = audio.reshape(-1, shape[-1])
    mel_spec = librosa.feature.melspectrogram(
        y=audio, sr=sr, n_fft=frame_size + 1, hop_length=hop_length, n_mels=n_mels
    )
    mel_spec = mel_spec.transpose(0, 2, 1)
    mel_spec = mel_spec.reshape(shape[:-1] + mel_spec.shape[1:])
    if to_db:
        for b in range(mel_spec.shape[0]):
            mel_spec[b, ...] = (librosa.power_to_db(mel_spec[b], ref=np.max) + 40) / 40
    return mel_spec


def _polyfit_val(mos: np.ndarray, personalized: bool) -> np.ndarray:
    """Use polyfit to convert raw mos values to DNSMOS values.

    Args:
        mos: the raw mos values, [..., 4]
        personalized: whether interfering speaker is penalized

    Returns:
        DNSMOS: [..., 4]

    """
    if personalized:
        p_ovr = np.poly1d([-0.00533021, 0.005101, 1.18058466, -0.11236046])
        p_sig = np.poly1d([-0.01019296, 0.02751166, 1.19576786, -0.24348726])
        p_bak = np.poly1d([-0.04976499, 0.44276479, -0.1644611, 0.96883132])
    else:
        p_ovr = np.poly1d([-0.06766283, 1.11546468, 0.04602535])
        p_sig = np.poly1d([-0.08397278, 1.22083953, 0.0052439])  # x**2*v0 + x**1*v1+ v2
        p_bak = np.poly1d([-0.13166888, 1.60915514, -0.39604546])

    mos[..., 1] = p_sig(mos[..., 1])
    mos[..., 2] = p_bak(mos[..., 2])
    mos[..., 3] = p_ovr(mos[..., 3])
    return mos


def deep_noise_suppression_mean_opinion_score(
    preds: Tensor,
    fs: int,
    personalized: bool,
    device: Optional[str] = None,
    num_threads: Optional[int] = None,
    cache_session: bool = True,
) -> Tensor:
    """Calculate `Deep Noise Suppression performance evaluation based on Mean Opinion Score`_ (DNSMOS).

    Human subjective evaluation is the ”gold standard” to evaluate speech quality optimized for human perception.
    Perceptual objective metrics serve as a proxy for subjective scores. The conventional and widely used metrics
    require a reference clean speech signal, which is unavailable in real recordings. The no-reference approaches
    correlate poorly with human ratings and are not widely adopted in the research community. One of the biggest
    use cases of these perceptual objective metrics is to evaluate noise suppression algorithms. DNSMOS generalizes
    well in challenging test conditions with a high correlation to human ratings in stack ranking noise suppression
    methods. More details can be found in `DNSMOS paper <https://arxiv.org/abs/2010.15258>`_ and
    `DNSMOS P.835 paper <https://arxiv.org/abs/2110.01763>`_.


    .. hint::
        Using this metric requires you to have ``librosa``, ``onnxruntime`` and ``requests`` installed. Install
        as ``pip install torchmetrics['audio']`` or alternatively ``pip install librosa onnxruntime-gpu requests``
        (if you do not have GPU enabled machine install ``onnxruntime`` instead of ``onnxruntime-gpu``)

    Args:
        preds: [..., time]
        fs: sampling frequency
        personalized: whether interfering speaker is penalized
        device: the device used for calculating DNSMOS, can be cpu or cuda:n, where n is the index of gpu.
            If None is given, then the device of input is used.
        num_threads: the number of threads to use for cpu inference. Defaults to None.
        cache_session: whether to cache the onnx session. By default this is true, meaning that repeated calls to this
            method is faster than if this was set to False, the consequence is that the session will be cached in
            memory until the process is terminated.

    Returns:
        Float tensor with shape ``(...,4)`` of DNSMOS values per sample, i.e. [p808_mos, mos_sig, mos_bak, mos_ovr]

    Raises:
        ModuleNotFoundError:
            If ``librosa``, ``onnxruntime`` or ``requests`` packages are not installed

    Example:
        >>> from torch import randn
        >>> from torchmetrics.functional.audio.dnsmos import deep_noise_suppression_mean_opinion_score
        >>> preds = randn(8000)
        >>> deep_noise_suppression_mean_opinion_score(preds, 8000, False)
        tensor([2.2..., 2.0..., 1.1..., 1.2...], dtype=torch.float64)

    """
    if not _LIBROSA_AVAILABLE or not _ONNXRUNTIME_AVAILABLE or not _REQUESTS_AVAILABLE:
        raise ModuleNotFoundError(
            "DNSMOS metric requires that librosa, onnxruntime and requests are installed."
            " Install as `pip install librosa onnxruntime-gpu requests`."
        )
    device = torch.device(device) if device is not None else preds.device

    _load_session_function = _cached_load_session if cache_session else _load_session
    onnx_sess = _load_session_function(
        f"{DNSMOS_DIR}/{'p' if personalized else ''}DNSMOS/sig_bak_ovr.onnx", device, num_threads
    )
    p808_onnx_sess = _load_session_function(f"{DNSMOS_DIR}/DNSMOS/model_v8.onnx", device, num_threads)

    desired_fs = SAMPLING_RATE
    if fs != desired_fs:
        audio = librosa.resample(preds.cpu().numpy(), orig_sr=fs, target_sr=desired_fs)
    else:
        audio = preds.cpu().numpy()

    len_samples = int(INPUT_LENGTH * desired_fs)
    while audio.shape[-1] < len_samples:
        audio = np.concatenate([audio, audio], axis=-1)

    num_hops = int(np.floor(audio.shape[-1] / desired_fs) - INPUT_LENGTH) + 1

    moss = []
    hop_len_samples = desired_fs
    for idx in range(num_hops):
        audio_seg = audio[..., int(idx * hop_len_samples) : int((idx + INPUT_LENGTH) * hop_len_samples)]
        if audio_seg.shape[-1] < len_samples:
            continue
        shape = audio_seg.shape
        audio_seg = audio_seg.reshape((-1, shape[-1]))

        input_features = np.array(audio_seg).astype("float32")
        p808_input_features = np.array(_audio_melspec(audio=audio_seg[..., :-160])).astype("float32")

        if device.type != "cpu" and (
            "CUDAExecutionProvider" in ort.get_available_providers()
            or "CoreMLExecutionProvider" in ort.get_available_providers()
        ):
            try:
                input_features = ort.OrtValue.ortvalue_from_numpy(input_features, device.type, device.index)
                p808_input_features = ort.OrtValue.ortvalue_from_numpy(p808_input_features, device.type, device.index)
            except Exception as e:
                rank_zero_warn(f"Failed to use GPU for DNSMOS, reverting to CPU. Error: {e}")

        oi = {"input_1": input_features}
        p808_oi = {"input_1": p808_input_features}
        mos_np = np.concatenate(
            [p808_onnx_sess.run(None, p808_oi)[0], onnx_sess.run(None, oi)[0]], axis=-1, dtype="float64"
        )
        mos_np = _polyfit_val(mos_np, personalized)

        mos_np = mos_np.reshape((*shape[:-1], 4))
        moss.append(mos_np)
    return torch.from_numpy(np.mean(np.stack(moss, axis=-1), axis=-1))  # [p808_mos, mos_sig, mos_bak, mos_ovr]