# Copyright (c) Facebook, Inc. and its affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.

import logging
import os, glob
import sys
from typing import Dict, List, Optional, Tuple

import numpy as np

from dataclasses import dataclass, field
from fairseq import metrics, search
from fairseq.data import Dictionary, encoders
from fairseq.dataclass.configs import FairseqDataclass
from fairseq.tasks import register_task
from fairseq.tasks.fairseq_task import FairseqTask
from omegaconf import MISSING, II
import numpy as np
from argparse import Namespace

DBG=True if len(sys.argv) == 1 else False

if DBG:
    from hubert_dataset import AVHubertDataset
    from sequence_generator import SequenceGenerator
else:
    from .hubert_dataset import AVHubertDataset
    from .sequence_generator import SequenceGenerator

logger = logging.getLogger(__name__)


class LabelEncoder(object):
    def __init__(self, dictionary: Dictionary) -> None:
        self.dictionary = dictionary

    def __call__(self, label: str) -> List[str]:
        return self.dictionary.encode_line(
            label, append_eos=False, add_if_not_exist=False,
        )

class LabelEncoderS2SToken(object):
    def __init__(self, dictionary: Dictionary, bpe_tokenizer) -> None:
        self.bpe_tokenizer = bpe_tokenizer
        self.dictionary = dictionary

    def __call__(self, label: str) -> List[str]:
        label = self.bpe_tokenizer.encode(label.lower())
        return self.dictionary.encode_line(
            label, append_eos=True, add_if_not_exist=False,
        ).long()

    def decode(self, tok, symbols_ignore=None):
        tok = self.dictionary.string(tok, extra_symbols_to_ignore=symbols_ignore)
        if self.bpe_tokenizer:
            tok = self.bpe_tokenizer.decode(tok)
        return tok

@dataclass
class AVHubertPretrainingConfig(FairseqDataclass):
    data: str = field(
        default=MISSING, metadata={"help": "path to data directory"}
    )
    labels: List[str] = field(
        default_factory=lambda: ["ltr"],
        metadata={
            "help": (
                "extension of the label files to load, frame-level labels for"
                " pre-training, and sequence-level label for fine-tuning"
            )
        },
    )
    label_dir: Optional[str] = field(
        default=None,
        metadata={
            "help": "if set, looks for labels in this directory instead",
        },
    )
    label_rate: int = field(
        default=-1,
        metadata={"help": "label frame rate. -1 for sequence label"},
    )

    sample_rate: int = field(
        default=16_000,
        metadata={
            "help": "target sample rate. audio files will be up/down "
            "sampled to this rate"
        },
    )
    normalize: bool = field(
        default=False,
        metadata={
            "help": "if set, normalizes input to have 0 mean and unit variance"
        },
    )
    enable_padding: bool = field(
        default=False,
        metadata={"help": "pad shorter samples instead of cropping"},
    )
    max_sample_size: Optional[int] = field(
        default=None,
        metadata={"help": "max sample size to keep in training"},
    )
    min_sample_size: Optional[int] = field(
        default=None,
        metadata={"help": "min sample size to keep in training"},
    )
    max_trim_sample_size: Optional[int] = field(
        default=II("task.max_sample_size"),
        metadata={"help": "max sample size to trim to for batching"},
    )
    single_target: Optional[bool] = field(
        default=False,
        metadata={
            "help": "if set, AddTargetDatasets outputs same keys "
            "as AddTargetDataset"
        },
    )
    random_crop: Optional[bool] = field(
        default=True,
        metadata={"help": "always crop from the beginning if false"},
    )
    pad_audio: Optional[bool] = field(
        default=False,
        metadata={"help": "pad audio to the longest one in the batch if true"},
    )
    pdb: Optional[bool] = field(
        default=False,
        metadata={"help": "pdb"},
    )
    stack_order_audio: int = field(
        default=1,
        metadata={"help": "concatenate n consecutive audio frames for one step"},
    )
    skip_verify: Optional[bool] = field(
        default=False,
        metadata={"help": "skip verifying label-audio alignment"},
    )
    image_aug: bool = field(default=False, metadata={'help': 'image data augmentation'})
    image_crop_size: int = field(
        default=88, metadata={"help": "image ROI size"})
    image_mean: float = field(
        default=0.421, metadata={"help": "image mean"})
    image_std: float = field(
        default=0.165, metadata={"help": "image std"})
    modalities: Optional[List[str]] = field(default_factory=lambda: ["audio", "video"], metadata={'help': 'modalities to load'})
    is_s2s: bool=field(default=False, metadata={'help': 'seq2seq fine-tuning only'})
    tokenizer_bpe_name: Optional[str] = field(default=None, metadata={'help': 'tokenizer model name'})
    tokenizer_bpe_model: Optional[str] = field(default=None, metadata={'help': 'tokenizer model path'})
    noise_wav: Optional[str] = field(default=None, metadata={'help': 'manifest of noise wav files (one wav file path per line)'})
    noise_prob: float = field(default=0, metadata={'help': 'noise probability'})
    noise_snr: Optional[str] = field(default='0', metadata={'help': 'noise SNR in audio'})
    noise_num: int = field(default=1, metadata={'help': 'number of noise wav files to mix'})
    fine_tuning: bool = field(default=False, metadata={"help": "set to true if fine-tuning AV-Hubert"})

@register_task("av_hubert_pretraining", dataclass=AVHubertPretrainingConfig)
class AVHubertPretrainingTask(FairseqTask):

    cfg: AVHubertPretrainingConfig

    def __init__(
        self,
        cfg: AVHubertPretrainingConfig,
    ) -> None:
        super().__init__(cfg)

        logger.info(f"current directory is {os.getcwd()}")
        logger.info(f"AVHubertPretrainingTask Config {cfg}")

        self.fine_tuning = cfg.fine_tuning
        if cfg.fine_tuning:
            self.state.add_factory("target_dictionary", self.load_dictionaries)
            if cfg.is_s2s:
                self.state.add_factory("s2s_tokenizer", self.load_tokenizer)
        else:
            self.state.add_factory("dictionaries", self.load_dictionaries)

        self.blank_symbol = "<s>"

    @property
    def source_dictionary(self) -> Optional[Dictionary]:
        return None # self._source_dictionary

    @property
    def target_dictionary(self) -> Optional[Dictionary]:
        return self.state.target_dictionary # self._target_dictionary

    @property
    def dictionaries(self) -> List[Dictionary]:
        return self.state.dictionaries

    def load_dictionaries(self):
        label_dir = self.cfg.data if self.cfg.label_dir is None else self.cfg.label_dir
        dictionaries = [
            Dictionary.load(f"{label_dir}/dict.{label}.txt")
            for label in self.cfg.labels
        ]
        return dictionaries[0] if self.cfg.fine_tuning else dictionaries

    def load_tokenizer(self):
        bpe_args = Namespace(**{'bpe': self.cfg.tokenizer_bpe_name, f"{self.cfg.tokenizer_bpe_name}_model": self.cfg.tokenizer_bpe_model})
        bpe_tokenizer = encoders.build_bpe(bpe_args)
        return bpe_tokenizer

    @property
    def s2s_tokenizer(self):
        return self.state.s2s_tokenizer

    @classmethod
    def setup_task(
        cls, cfg: AVHubertPretrainingConfig, **kwargs
    ) -> "AVHubertPretrainingTask":
        if cfg.pdb:
            import pdb
            pdb.set_trace()
        return cls(cfg)

    def get_label_dir(self) -> str:
        if self.cfg.label_dir is None:
            return self.cfg.data
        return self.cfg.label_dir

    def load_dataset(self, split: str, **kwargs) -> None:
        manifest = f"{self.cfg.data}/{split}.tsv"
        dictionaries = [self.target_dictionary] if self.fine_tuning else self.dictionaries
        pad_list = [dictionary.pad() for dictionary in dictionaries]
        eos_list = [dictionary.eos() for dictionary in dictionaries]
        if not self.cfg.is_s2s:
            procs = [LabelEncoder(dictionary) for dictionary in dictionaries]
        else:
            logger.info(f"Using tokenizer")
            bpe_tokenizer = self.s2s_tokenizer
            procs = [LabelEncoderS2SToken(dictionary, bpe_tokenizer) for dictionary in dictionaries]
        paths = [
            f"{self.get_label_dir()}/{split}.{l}" for l in self.cfg.labels
        ]
        image_aug = self.cfg.image_aug if split == 'train' else False
        noise_fn, noise_snr = f"{self.cfg.noise_wav}/{split}.tsv" if self.cfg.noise_wav is not None else None, eval(self.cfg.noise_snr)
        noise_num = self.cfg.noise_num # 
        self.datasets[split] = AVHubertDataset(
            manifest,
            sample_rate=self.cfg.sample_rate,
            label_paths=paths,
            label_rates=self.cfg.label_rate,
            pad_list=pad_list,
            eos_list=eos_list,
            label_processors=procs,
            max_keep_sample_size=self.cfg.max_sample_size,
            min_keep_sample_size=self.cfg.min_sample_size,
            max_sample_size=self.cfg.max_trim_sample_size,
            pad_audio=self.cfg.pad_audio,
            normalize=self.cfg.normalize,
            store_labels=False,
            random_crop=self.cfg.random_crop,
            single_target=self.cfg.single_target,
            stack_order_audio=self.cfg.stack_order_audio,
            skip_verify=self.cfg.skip_verify,
            image_mean=self.cfg.image_mean,
            image_std=self.cfg.image_std,
            image_crop_size=self.cfg.image_crop_size,
            image_aug=image_aug,
            modalities=self.cfg.modalities,
            is_s2s=self.cfg.is_s2s,
            noise_fn=noise_fn,
            noise_prob=self.cfg.noise_prob,
            noise_snr=noise_snr,
            noise_num=noise_num
        )

    def max_positions(self) -> Tuple[int, int]:
        return (sys.maxsize, sys.maxsize)

    def filter_indices_by_size(
        self, indices: np.array, *args, **kwargs
    ) -> np.array:
        return indices

    def build_generator(
        self, models, args, seq_gen_cls=None, extra_gen_cls_kwargs=None, prefix_allowed_tokens_fn=None,
    ):
        """
        Build a :class:`~fairseq.SequenceGenerator` instance for this
        task.
        Args:
            models (List[~fairseq.models.FairseqModel]): ensemble of models
            args (fairseq.dataclass.configs.GenerationConfig):
                configuration object (dataclass) for generation
            extra_gen_cls_kwargs (Dict[str, Any]): extra options to pass
                through to SequenceGenerator
            prefix_allowed_tokens_fn (Callable[[int, torch.Tensor], List[int]]):
                If provided, this function constrains the beam search to
                allowed tokens only at each step. The provided function
                should take 2 arguments: the batch ID (`batch_id: int`)
                and a unidimensional tensor of token ids (`inputs_ids:
                torch.Tensor`). It has to return a `List[int]` with the
                allowed tokens for the next generation step conditioned
                on the previously generated tokens (`inputs_ids`) and
                the batch ID (`batch_id`). This argument is useful for
                constrained generation conditioned on the prefix, as
                described in "Autoregressive Entity Retrieval"
                (https://arxiv.org/abs/2010.00904) and
                https://github.com/facebookresearch/GENRE.
        """
        if getattr(args, "score_reference", False):
            from fairseq.sequence_scorer import SequenceScorer

            return SequenceScorer(
                self.target_dictionary,
                compute_alignment=getattr(args, "print_alignment", False),
            )

        # Choose search strategy. Defaults to Beam Search.
        sampling = getattr(args, "sampling", False)
        sampling_topk = getattr(args, "sampling_topk", -1)
        sampling_topp = getattr(args, "sampling_topp", -1.0)
        diverse_beam_groups = getattr(args, "diverse_beam_groups", -1)
        diverse_beam_strength = getattr(args, "diverse_beam_strength", 0.5)
        match_source_len = getattr(args, "match_source_len", False)
        diversity_rate = getattr(args, "diversity_rate", -1)
        constrained = getattr(args, "constraints", False)
        if prefix_allowed_tokens_fn is None:
            prefix_allowed_tokens_fn = getattr(args, "prefix_allowed_tokens_fn", None)
        if (
            sum(
                int(cond)
                for cond in [
                    sampling,
                    diverse_beam_groups > 0,
                    match_source_len,
                    diversity_rate > 0,
                ]
            )
            > 1
        ):
            raise ValueError("Provided Search parameters are mutually exclusive.")
        assert sampling_topk < 0 or sampling, "--sampling-topk requires --sampling"
        assert sampling_topp < 0 or sampling, "--sampling-topp requires --sampling"

        if sampling:
            search_strategy = search.Sampling(
                self.target_dictionary, sampling_topk, sampling_topp
            )
        elif diverse_beam_groups > 0:
            search_strategy = search.DiverseBeamSearch(
                self.target_dictionary, diverse_beam_groups, diverse_beam_strength
            )
        elif match_source_len:
            # this is useful for tagging applications where the output
            # length should match the input length, so we hardcode the
            # length constraints for simplicity
            search_strategy = search.LengthConstrainedBeamSearch(
                self.target_dictionary,
                min_len_a=1,
                min_len_b=0,
                max_len_a=1,
                max_len_b=0,
            )
        elif diversity_rate > -1:
            search_strategy = search.DiverseSiblingsSearch(
                self.target_dictionary, diversity_rate
            )
        elif constrained:
            search_strategy = search.LexicallyConstrainedBeamSearch(
                self.target_dictionary, args.constraints
            )
        elif prefix_allowed_tokens_fn:
            search_strategy = search.PrefixConstrainedBeamSearch(
                self.target_dictionary, prefix_allowed_tokens_fn
            )
        else:
            search_strategy = search.BeamSearch(self.target_dictionary)

        extra_gen_cls_kwargs = extra_gen_cls_kwargs or {}
        if seq_gen_cls is None:
            if getattr(args, "print_alignment", False):
                seq_gen_cls = SequenceGeneratorWithAlignment
                extra_gen_cls_kwargs["print_alignment"] = args.print_alignment
            else:
                seq_gen_cls = SequenceGenerator

        return seq_gen_cls(
            models,
            self.target_dictionary,
            beam_size=getattr(args, "beam", 5),
            max_len_a=getattr(args, "max_len_a", 0),
            max_len_b=getattr(args, "max_len_b", 200),
            min_len=getattr(args, "min_len", 1),
            normalize_scores=(not getattr(args, "unnormalized", False)),
            len_penalty=getattr(args, "lenpen", 1),
            unk_penalty=getattr(args, "unkpen", 0),
            temperature=getattr(args, "temperature", 1.0),
            match_source_len=getattr(args, "match_source_len", False),
            no_repeat_ngram_size=getattr(args, "no_repeat_ngram_size", 0),
            search_strategy=search_strategy,
            **extra_gen_cls_kwargs,
        )
