# Copyright (c) 2020, NVIDIA CORPORATION.  All rights reserved.
#
# 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 contextlib
from dataclasses import dataclass, field
from typing import Any, Dict, List, Optional

import torch
from hydra.utils import instantiate
from omegaconf import MISSING, DictConfig, OmegaConf, open_dict
from omegaconf.errors import ConfigAttributeError
from pytorch_lightning.loggers import TensorBoardLogger, WandbLogger
from torch import nn

from nemo.collections.common.parts.preprocessing import parsers
from nemo.collections.tts.losses.tacotron2loss import Tacotron2Loss
from nemo.collections.tts.models.base import SpectrogramGenerator
from nemo.collections.tts.parts.utils.helpers import (
    g2p_backward_compatible_support,
    get_mask_from_lengths,
    tacotron2_log_to_tb_func,
    tacotron2_log_to_wandb_func,
)
from nemo.core.classes.common import PretrainedModelInfo, typecheck
from nemo.core.neural_types.elements import (
    AudioSignal,
    EmbeddedTextType,
    LengthsType,
    LogitsType,
    MelSpectrogramType,
    SequenceToSequenceAlignmentType,
)
from nemo.core.neural_types.neural_type import NeuralType
from nemo.utils import logging, model_utils


@dataclass
class Preprocessor:
    _target_: str = MISSING
    pad_value: float = MISSING


@dataclass
class Tacotron2Config:
    preprocessor: Preprocessor = field(default_factory=lambda: Preprocessor())
    encoder: Dict[Any, Any] = MISSING
    decoder: Dict[Any, Any] = MISSING
    postnet: Dict[Any, Any] = MISSING
    labels: List = MISSING
    train_ds: Optional[Dict[Any, Any]] = None
    validation_ds: Optional[Dict[Any, Any]] = None


class Tacotron2Model(SpectrogramGenerator):
    """Tacotron 2 Model that is used to generate mel spectrograms from text"""

    def __init__(self, cfg: DictConfig, trainer: 'Trainer' = None):
        # Convert to Hydra 1.0 compatible DictConfig
        cfg = model_utils.convert_model_config_to_dict_config(cfg)
        cfg = model_utils.maybe_update_config_version(cfg)

        # setup normalizer
        self.normalizer = None
        self.text_normalizer_call = None
        self.text_normalizer_call_kwargs = {}
        self._setup_normalizer(cfg)

        # setup tokenizer
        self.tokenizer = None
        if hasattr(cfg, 'text_tokenizer'):
            self._setup_tokenizer(cfg)

            self.num_tokens = len(self.tokenizer.tokens)
            self.tokenizer_pad = self.tokenizer.pad
            self.tokenizer_unk = self.tokenizer.oov
            # assert self.tokenizer is not None
        else:
            self.num_tokens = len(cfg.labels) + 3

        super().__init__(cfg=cfg, trainer=trainer)

        schema = OmegaConf.structured(Tacotron2Config)
        # ModelPT ensures that cfg is a DictConfig, but do this second check in case ModelPT changes
        if isinstance(cfg, dict):
            cfg = OmegaConf.create(cfg)
        elif not isinstance(cfg, DictConfig):
            raise ValueError(f"cfg was type: {type(cfg)}. Expected either a dict or a DictConfig")
        # Ensure passed cfg is compliant with schema
        try:
            OmegaConf.merge(cfg, schema)
            self.pad_value = cfg.preprocessor.pad_value
        except ConfigAttributeError:
            self.pad_value = cfg.preprocessor.params.pad_value
            logging.warning(
                "Your config is using an old NeMo yaml configuration. Please ensure that the yaml matches the "
                "current version in the main branch for future compatibility."
            )

        self._parser = None
        self.audio_to_melspec_precessor = instantiate(cfg.preprocessor)
        self.text_embedding = nn.Embedding(self.num_tokens, 512)
        self.encoder = instantiate(self._cfg.encoder)
        self.decoder = instantiate(self._cfg.decoder)
        self.postnet = instantiate(self._cfg.postnet)
        self.loss = Tacotron2Loss()
        self.calculate_loss = True

    @property
    def parser(self):
        if self._parser is not None:
            return self._parser

        ds_class_name = self._cfg.train_ds.dataset._target_.split(".")[-1]
        if ds_class_name == "TTSDataset":
            self._parser = None
        elif hasattr(self._cfg, "labels"):
            self._parser = parsers.make_parser(
                labels=self._cfg.labels,
                name='en',
                unk_id=-1,
                blank_id=-1,
                do_normalize=True,
                abbreviation_version="fastpitch",
                make_table=False,
            )
        else:
            raise ValueError("Wanted to setup parser, but model does not have necessary paramaters")

        return self._parser

    def parse(self, text: str, normalize=True) -> torch.Tensor:
        if self.training:
            logging.warning("parse() is meant to be called in eval mode.")
        if normalize and self.text_normalizer_call is not None:
            text = self.text_normalizer_call(text, **self.text_normalizer_call_kwargs)

        eval_phon_mode = contextlib.nullcontext()
        if hasattr(self.tokenizer, "set_phone_prob"):
            eval_phon_mode = self.tokenizer.set_phone_prob(prob=1.0)

        with eval_phon_mode:
            if self.tokenizer is not None:
                tokens = self.tokenizer.encode(text)
            else:
                tokens = self.parser(text)
                # Old parser doesn't add bos and eos ids, so maunally add it
                tokens = [len(self._cfg.labels)] + tokens + [len(self._cfg.labels) + 1]
        tokens_tensor = torch.tensor(tokens).unsqueeze_(0).to(self.device)
        return tokens_tensor

    @property
    def input_types(self):
        if self.training:
            return {
                "tokens": NeuralType(('B', 'T'), EmbeddedTextType()),
                "token_len": NeuralType(('B'), LengthsType()),
                "audio": NeuralType(('B', 'T'), AudioSignal()),
                "audio_len": NeuralType(('B'), LengthsType()),
            }
        else:
            return {
                "tokens": NeuralType(('B', 'T'), EmbeddedTextType()),
                "token_len": NeuralType(('B'), LengthsType()),
                "audio": NeuralType(('B', 'T'), AudioSignal(), optional=True),
                "audio_len": NeuralType(('B'), LengthsType(), optional=True),
            }

    @property
    def output_types(self):
        if not self.calculate_loss and not self.training:
            return {
                "spec_pred_dec": NeuralType(('B', 'D', 'T'), MelSpectrogramType()),
                "spec_pred_postnet": NeuralType(('B', 'D', 'T'), MelSpectrogramType()),
                "gate_pred": NeuralType(('B', 'T'), LogitsType()),
                "alignments": NeuralType(('B', 'T', 'T'), SequenceToSequenceAlignmentType()),
                "pred_length": NeuralType(('B'), LengthsType()),
            }
        return {
            "spec_pred_dec": NeuralType(('B', 'D', 'T'), MelSpectrogramType()),
            "spec_pred_postnet": NeuralType(('B', 'D', 'T'), MelSpectrogramType()),
            "gate_pred": NeuralType(('B', 'T'), LogitsType()),
            "spec_target": NeuralType(('B', 'D', 'T'), MelSpectrogramType()),
            "spec_target_len": NeuralType(('B'), LengthsType()),
            "alignments": NeuralType(('B', 'T', 'T'), SequenceToSequenceAlignmentType()),
        }

    @typecheck()
    def forward(self, *, tokens, token_len, audio=None, audio_len=None):
        if audio is not None and audio_len is not None:
            spec_target, spec_target_len = self.audio_to_melspec_precessor(audio, audio_len)
        else:
            if self.training or self.calculate_loss:
                raise ValueError(
                    f"'audio' and 'audio_len' can not be None when either 'self.training' or 'self.calculate_loss' is True."
                )

        token_embedding = self.text_embedding(tokens).transpose(1, 2)
        encoder_embedding = self.encoder(token_embedding=token_embedding, token_len=token_len)

        if self.training:
            spec_pred_dec, gate_pred, alignments = self.decoder(
                memory=encoder_embedding, decoder_inputs=spec_target, memory_lengths=token_len
            )
        else:
            spec_pred_dec, gate_pred, alignments, pred_length = self.decoder(
                memory=encoder_embedding, memory_lengths=token_len
            )

        spec_pred_postnet = self.postnet(mel_spec=spec_pred_dec)

        if not self.calculate_loss and not self.training:
            return spec_pred_dec, spec_pred_postnet, gate_pred, alignments, pred_length

        return spec_pred_dec, spec_pred_postnet, gate_pred, spec_target, spec_target_len, alignments

    @typecheck(
        input_types={"tokens": NeuralType(('B', 'T'), EmbeddedTextType())},
        output_types={"spec": NeuralType(('B', 'D', 'T'), MelSpectrogramType())},
    )
    def generate_spectrogram(self, *, tokens):
        self.eval()
        self.calculate_loss = False
        token_len = torch.tensor([len(i) for i in tokens]).to(self.device)
        tensors = self(tokens=tokens, token_len=token_len)
        spectrogram_pred = tensors[1]

        if spectrogram_pred.shape[0] > 1:
            # Silence all frames past the predicted end
            mask = ~get_mask_from_lengths(tensors[-1])
            mask = mask.expand(spectrogram_pred.shape[1], mask.size(0), mask.size(1))
            mask = mask.permute(1, 0, 2)
            spectrogram_pred.data.masked_fill_(mask, self.pad_value)

        return spectrogram_pred

    def training_step(self, batch, batch_idx):
        audio, audio_len, tokens, token_len = batch
        spec_pred_dec, spec_pred_postnet, gate_pred, spec_target, spec_target_len, _ = self.forward(
            audio=audio, audio_len=audio_len, tokens=tokens, token_len=token_len
        )

        loss, _ = self.loss(
            spec_pred_dec=spec_pred_dec,
            spec_pred_postnet=spec_pred_postnet,
            gate_pred=gate_pred,
            spec_target=spec_target,
            spec_target_len=spec_target_len,
            pad_value=self.pad_value,
        )

        output = {
            'loss': loss,
            'progress_bar': {'training_loss': loss},
            'log': {'loss': loss},
        }
        return output

    def validation_step(self, batch, batch_idx):
        audio, audio_len, tokens, token_len = batch
        spec_pred_dec, spec_pred_postnet, gate_pred, spec_target, spec_target_len, alignments = self.forward(
            audio=audio, audio_len=audio_len, tokens=tokens, token_len=token_len
        )

        loss, gate_target = self.loss(
            spec_pred_dec=spec_pred_dec,
            spec_pred_postnet=spec_pred_postnet,
            gate_pred=gate_pred,
            spec_target=spec_target,
            spec_target_len=spec_target_len,
            pad_value=self.pad_value,
        )
        loss = {
            "val_loss": loss,
            "mel_target": spec_target,
            "mel_postnet": spec_pred_postnet,
            "gate": gate_pred,
            "gate_target": gate_target,
            "alignments": alignments,
        }
        self.validation_step_outputs.append(loss)
        return loss

    def on_validation_epoch_end(self):
        if self.logger is not None and self.logger.experiment is not None:
            logger = self.logger.experiment
            for logger in self.trainer.loggers:
                if isinstance(logger, TensorBoardLogger):
                    logger = logger.experiment
                    break
            if isinstance(logger, TensorBoardLogger):
                tacotron2_log_to_tb_func(
                    logger,
                    self.validation_step_outputs[0].values(),
                    self.global_step,
                    tag="val",
                    log_images=True,
                    add_audio=False,
                )
            elif isinstance(logger, WandbLogger):
                tacotron2_log_to_wandb_func(
                    logger,
                    self.validation_step_outputs[0].values(),
                    self.global_step,
                    tag="val",
                    log_images=True,
                    add_audio=False,
                )
        avg_loss = torch.stack(
            [x['val_loss'] for x in self.validation_step_outputs]
        ).mean()  # This reduces across batches, not workers!
        self.log('val_loss', avg_loss)
        self.validation_step_outputs.clear()  # free memory

    def _setup_normalizer(self, cfg):
        if "text_normalizer" in cfg:
            normalizer_kwargs = {}

            if "whitelist" in cfg.text_normalizer:
                normalizer_kwargs["whitelist"] = self.register_artifact(
                    'text_normalizer.whitelist', cfg.text_normalizer.whitelist
                )

            try:
                import nemo_text_processing

                self.normalizer = instantiate(cfg.text_normalizer, **normalizer_kwargs)
            except Exception as e:
                logging.error(e)
                raise ImportError(
                    "`nemo_text_processing` not installed, see https://github.com/NVIDIA/NeMo-text-processing for more details"
                )

            self.text_normalizer_call = self.normalizer.normalize
            if "text_normalizer_call_kwargs" in cfg:
                self.text_normalizer_call_kwargs = cfg.text_normalizer_call_kwargs

    def _setup_tokenizer(self, cfg):
        text_tokenizer_kwargs = {}
        if "g2p" in cfg.text_tokenizer and cfg.text_tokenizer.g2p is not None:
            # for backward compatibility
            if (
                self._is_model_being_restored()
                and (cfg.text_tokenizer.g2p.get('_target_', None) is not None)
                and cfg.text_tokenizer.g2p["_target_"].startswith("nemo_text_processing.g2p")
            ):
                cfg.text_tokenizer.g2p["_target_"] = g2p_backward_compatible_support(
                    cfg.text_tokenizer.g2p["_target_"]
                )

            g2p_kwargs = {}

            if "phoneme_dict" in cfg.text_tokenizer.g2p:
                g2p_kwargs["phoneme_dict"] = self.register_artifact(
                    'text_tokenizer.g2p.phoneme_dict', cfg.text_tokenizer.g2p.phoneme_dict,
                )

            if "heteronyms" in cfg.text_tokenizer.g2p:
                g2p_kwargs["heteronyms"] = self.register_artifact(
                    'text_tokenizer.g2p.heteronyms', cfg.text_tokenizer.g2p.heteronyms,
                )

            text_tokenizer_kwargs["g2p"] = instantiate(cfg.text_tokenizer.g2p, **g2p_kwargs)

        self.tokenizer = instantiate(cfg.text_tokenizer, **text_tokenizer_kwargs)

    def __setup_dataloader_from_config(self, cfg, shuffle_should_be: bool = True, name: str = "train"):
        if "dataset" not in cfg or not isinstance(cfg.dataset, DictConfig):
            raise ValueError(f"No dataset for {name}")
        if "dataloader_params" not in cfg or not isinstance(cfg.dataloader_params, DictConfig):
            raise ValueError(f"No dataloder_params for {name}")
        if shuffle_should_be:
            if 'shuffle' not in cfg.dataloader_params:
                logging.warning(
                    f"Shuffle should be set to True for {self}'s {name} dataloader but was not found in its "
                    "config. Manually setting to True"
                )
                with open_dict(cfg.dataloader_params):
                    cfg.dataloader_params.shuffle = True
            elif not cfg.dataloader_params.shuffle:
                logging.error(f"The {name} dataloader for {self} has shuffle set to False!!!")
        elif not shuffle_should_be and cfg.dataloader_params.shuffle:
            logging.error(f"The {name} dataloader for {self} has shuffle set to True!!!")

        dataset = instantiate(
            cfg.dataset,
            text_normalizer=self.normalizer,
            text_normalizer_call_kwargs=self.text_normalizer_call_kwargs,
            text_tokenizer=self.tokenizer,
        )

        return torch.utils.data.DataLoader(dataset, collate_fn=dataset.collate_fn, **cfg.dataloader_params)

    def setup_training_data(self, cfg):
        self._train_dl = self.__setup_dataloader_from_config(cfg)

    def setup_validation_data(self, cfg):
        self._validation_dl = self.__setup_dataloader_from_config(cfg, shuffle_should_be=False, name="validation")

    @classmethod
    def list_available_models(cls) -> 'List[PretrainedModelInfo]':
        """
        This method returns a list of pre-trained model which can be instantiated directly from NVIDIA's NGC cloud.
        Returns:
            List of available pre-trained models.
        """
        list_of_models = []
        model = PretrainedModelInfo(
            pretrained_model_name="tts_en_tacotron2",
            location="https://api.ngc.nvidia.com/v2/models/nvidia/nemo/tts_en_tacotron2/versions/1.10.0/files/tts_en_tacotron2.nemo",
            description="This model is trained on LJSpeech sampled at 22050Hz, and can be used to generate female English voices with an American accent.",
            class_=cls,
            aliases=["Tacotron2-22050Hz"],
        )
        list_of_models.append(model)
        return list_of_models
