import os
import yaml
import torch
import numpy as np
from torch.nn import functional as F


def sequence_mask(lengths, maxlen=None, dtype=torch.float32, device=None):
    if maxlen is None:
        maxlen = lengths.max()
    row_vector = torch.arange(0, maxlen, 1).to(lengths.device)
    matrix = torch.unsqueeze(lengths, dim=-1)
    mask = row_vector < matrix
    mask = mask.detach()

    return mask.type(dtype).to(device) if device is not None else mask.type(dtype)


def apply_cmvn(inputs, mvn):
    device = inputs.device
    dtype = inputs.dtype
    frame, dim = inputs.shape
    meams = np.tile(mvn[0:1, :dim], (frame, 1))
    vars = np.tile(mvn[1:2, :dim], (frame, 1))
    inputs -= torch.from_numpy(meams).type(dtype).to(device)
    inputs *= torch.from_numpy(vars).type(dtype).to(device)

    return inputs.type(torch.float32)


def drop_and_add(
    inputs: torch.Tensor,
    outputs: torch.Tensor,
    training: bool,
    dropout_rate: float = 0.1,
    stoch_layer_coeff: float = 1.0,
):

    outputs = F.dropout(outputs, p=dropout_rate, training=training, inplace=True)
    outputs *= stoch_layer_coeff

    input_dim = inputs.size(-1)
    output_dim = outputs.size(-1)

    if input_dim == output_dim:
        outputs += inputs
    return outputs


def proc_tf_vocab(vocab_path):
    with open(vocab_path, encoding="utf-8") as f:
        token_list = [line.rstrip() for line in f]
        if "<unk>" not in token_list:
            token_list.append("<unk>")
    return token_list


def gen_config_for_tfmodel(config_path, vocab_path, output_dir):
    token_list = proc_tf_vocab(vocab_path)
    with open(config_path, encoding="utf-8") as f:
        config = yaml.safe_load(f)

    config["token_list"] = token_list

    if not os.path.exists(output_dir):
        os.makedirs(output_dir)

    with open(os.path.join(output_dir, "config.yaml"), "w", encoding="utf-8") as f:
        yaml_no_alias_safe_dump(config, f, indent=4, sort_keys=False)


class NoAliasSafeDumper(yaml.SafeDumper):
    # Disable anchor/alias in yaml because looks ugly
    def ignore_aliases(self, data):
        return True


def yaml_no_alias_safe_dump(data, stream=None, **kwargs):
    """Safe-dump in yaml with no anchor/alias"""
    return yaml.dump(
        data, stream, allow_unicode=True, Dumper=NoAliasSafeDumper, **kwargs
    )


if __name__ == "__main__":
    import sys

    config_path = sys.argv[1]
    vocab_path = sys.argv[2]
    output_dir = sys.argv[3]
    gen_config_for_tfmodel(config_path, vocab_path, output_dir)
