# 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 torch
from torch import Tensor
from torch.nn import functional as F
from torch.nn.utils.rnn import pack_padded_sequence, pad_packed_sequence

from nemo.core.classes import NeuralModule, adapter_mixins
from nemo.core.neural_types.elements import EncodedRepresentation, Index, LengthsType, MelSpectrogramType
from nemo.core.neural_types.neural_type import NeuralType
from nemo.utils import logging


SUPPORTED_CONDITION_TYPES = ["add", "concat", "layernorm"]


def check_support_condition_types(condition_types):
    for tp in condition_types:
        if tp not in SUPPORTED_CONDITION_TYPES:
            raise ValueError(f"Unknown conditioning type {tp}")


def masked_instance_norm(
    input: Tensor,
    mask: Tensor,
    weight: Tensor,
    bias: Tensor,
    momentum: float,
    eps: float = 1e-5,
) -> Tensor:
    r"""Applies Masked Instance Normalization for each channel in each data sample in a batch.

    See :class:`~MaskedInstanceNorm1d` for details.
    """
    lengths = mask.sum((-1,))
    mean = (input * mask).sum((-1,)) / lengths  # (N, C)
    var = (((input - mean[(..., None)]) * mask) ** 2).sum((-1,)) / lengths  # (N, C)
    out = (input - mean[(..., None)]) / torch.sqrt(var[(..., None)] + eps)  # (N, C, ...)
    out = out * weight[None, :][(..., None)] + bias[None, :][(..., None)]

    return out


class MaskedInstanceNorm1d(torch.nn.InstanceNorm1d):
    r"""Applies Instance Normalization over a masked 3D input
    (a mini-batch of 1D inputs with additional channel dimension)..

    See documentation of :class:`~torch.nn.InstanceNorm1d` for details.

    Shape:
        - Input: :math:`(N, C, L)`
        - Mask: :math:`(N, 1, L)`
        - Output: :math:`(N, C, L)` (same shape as input)
    """

    def __init__(
        self,
        num_features: int,
        eps: float = 1e-5,
        momentum: float = 0.1,
        affine: bool = False,
        track_running_stats: bool = False,
    ) -> None:
        super(MaskedInstanceNorm1d, self).__init__(num_features, eps, momentum, affine, track_running_stats)

    def forward(self, input: Tensor, mask: Tensor) -> Tensor:
        return masked_instance_norm(
            input,
            mask,
            self.weight,
            self.bias,
            self.momentum,
            self.eps,
        )


class PartialConv1d(torch.nn.Conv1d):
    """
    Zero padding creates a unique identifier for where the edge of the data is, such that the model can almost always identify
    exactly where it is relative to either edge given a sufficient receptive field. Partial padding goes to some lengths to remove
    this affect.
    """

    __constants__ = ['slide_winsize']
    slide_winsize: float

    def __init__(self, *args, **kwargs):
        super(PartialConv1d, self).__init__(*args, **kwargs)
        weight_maskUpdater = torch.ones(1, 1, self.kernel_size[0])
        self.register_buffer("weight_maskUpdater", weight_maskUpdater, persistent=False)
        self.slide_winsize = self.weight_maskUpdater.shape[1] * self.weight_maskUpdater.shape[2]

    def forward(self, input, mask_in):
        if mask_in is None:
            mask = torch.ones(1, 1, input.shape[2], dtype=input.dtype, device=input.device)
        else:
            mask = mask_in
            input = torch.mul(input, mask)
        with torch.no_grad():
            update_mask = F.conv1d(
                mask,
                self.weight_maskUpdater,
                bias=None,
                stride=self.stride,
                padding=self.padding,
                dilation=self.dilation,
                groups=1,
            )
            update_mask_filled = torch.masked_fill(update_mask, update_mask == 0, self.slide_winsize)
            mask_ratio = self.slide_winsize / update_mask_filled
            update_mask = torch.clamp(update_mask, 0, 1)
            mask_ratio = torch.mul(mask_ratio, update_mask)

        raw_out = self._conv_forward(input, self.weight, self.bias)

        if self.bias is not None:
            bias_view = self.bias.view(1, self.out_channels, 1)
            output = torch.mul(raw_out - bias_view, mask_ratio) + bias_view
            output = torch.mul(output, update_mask)
        else:
            output = torch.mul(raw_out, mask_ratio)

        return output


class LinearNorm(torch.nn.Module):
    def __init__(self, in_dim, out_dim, bias=True, w_init_gain='linear'):
        super().__init__()
        self.linear_layer = torch.nn.Linear(in_dim, out_dim, bias=bias)

        torch.nn.init.xavier_uniform_(self.linear_layer.weight, gain=torch.nn.init.calculate_gain(w_init_gain))

    def forward(self, x):
        return self.linear_layer(x)


class ConvNorm(torch.nn.Module, adapter_mixins.AdapterModuleMixin):
    __constants__ = ['use_partial_padding']
    use_partial_padding: bool

    def __init__(
        self,
        in_channels,
        out_channels,
        kernel_size=1,
        stride=1,
        padding=None,
        dilation=1,
        bias=True,
        w_init_gain='linear',
        use_partial_padding=False,
        use_weight_norm=False,
        norm_fn=None,
    ):
        super(ConvNorm, self).__init__()
        if padding is None:
            assert kernel_size % 2 == 1
            padding = int(dilation * (kernel_size - 1) / 2)
        self.use_partial_padding = use_partial_padding
        conv_fn = torch.nn.Conv1d
        if use_partial_padding:
            conv_fn = PartialConv1d
        self.conv = conv_fn(
            in_channels,
            out_channels,
            kernel_size=kernel_size,
            stride=stride,
            padding=padding,
            dilation=dilation,
            bias=bias,
        )
        torch.nn.init.xavier_uniform_(self.conv.weight, gain=torch.nn.init.calculate_gain(w_init_gain))
        if use_weight_norm:
            self.conv = torch.nn.utils.weight_norm(self.conv)
        if norm_fn is not None:
            self.norm = norm_fn(out_channels, affine=True)
        else:
            self.norm = None

    def forward(self, signal, mask=None):
        if self.use_partial_padding:
            ret = self.conv(signal, mask)
            if self.norm is not None:
                ret = self.norm(ret, mask)
        else:
            if mask is not None:
                signal = signal.mul(mask)
            ret = self.conv(signal)
            if self.norm is not None:
                ret = self.norm(ret)

        if self.is_adapter_available():
            ret = self.forward_enabled_adapters(ret.transpose(1, 2)).transpose(1, 2)

        return ret


class LocationLayer(torch.nn.Module):
    def __init__(self, attention_n_filters, attention_kernel_size, attention_dim):
        super().__init__()
        padding = int((attention_kernel_size - 1) / 2)
        self.location_conv = ConvNorm(
            2,
            attention_n_filters,
            kernel_size=attention_kernel_size,
            padding=padding,
            bias=False,
            stride=1,
            dilation=1,
        )
        self.location_dense = LinearNorm(attention_n_filters, attention_dim, bias=False, w_init_gain='tanh')

    def forward(self, attention_weights_cat):
        processed_attention = self.location_conv(attention_weights_cat)
        processed_attention = processed_attention.transpose(1, 2)
        processed_attention = self.location_dense(processed_attention)
        return processed_attention


class Attention(torch.nn.Module):
    def __init__(
        self,
        attention_rnn_dim,
        embedding_dim,
        attention_dim,
        attention_location_n_filters,
        attention_location_kernel_size,
    ):
        super().__init__()
        self.query_layer = LinearNorm(attention_rnn_dim, attention_dim, bias=False, w_init_gain='tanh')
        self.memory_layer = LinearNorm(embedding_dim, attention_dim, bias=False, w_init_gain='tanh')
        self.v = LinearNorm(attention_dim, 1, bias=False)
        self.location_layer = LocationLayer(
            attention_location_n_filters,
            attention_location_kernel_size,
            attention_dim,
        )
        self.score_mask_value = -float("inf")

    def get_alignment_energies(self, query, processed_memory, attention_weights_cat):
        """
        PARAMS
        ------
        query: decoder output (batch, n_mel_channels * n_frames_per_step)
        processed_memory: processed encoder outputs (B, T_in, attention_dim)
        attention_weights_cat: cumulative and prev. att weights (B, 2, max_time)
        RETURNS
        -------
        alignment (batch, max_time)
        """

        processed_query = self.query_layer(query.unsqueeze(1))
        processed_attention_weights = self.location_layer(attention_weights_cat)
        energies = self.v(torch.tanh(processed_query + processed_attention_weights + processed_memory))

        energies = energies.squeeze(-1)
        return energies

    def forward(
        self,
        attention_hidden_state,
        memory,
        processed_memory,
        attention_weights_cat,
        mask,
    ):
        """
        PARAMS
        ------
        attention_hidden_state: attention rnn last output
        memory: encoder outputs
        processed_memory: processed encoder outputs
        attention_weights_cat: previous and cummulative attention weights
        mask: binary mask for padded data
        """
        alignment = self.get_alignment_energies(attention_hidden_state, processed_memory, attention_weights_cat)

        if mask is not None:
            alignment.data.masked_fill_(mask, self.score_mask_value)

        attention_weights = F.softmax(alignment, dim=1)
        attention_context = torch.bmm(attention_weights.unsqueeze(1), memory)
        attention_context = attention_context.squeeze(1)

        return attention_context, attention_weights


class Prenet(torch.nn.Module):
    def __init__(self, in_dim, sizes, p_dropout=0.5):
        super().__init__()
        in_sizes = [in_dim] + sizes[:-1]
        self.p_dropout = p_dropout
        self.layers = torch.nn.ModuleList(
            [LinearNorm(in_size, out_size, bias=False) for (in_size, out_size) in zip(in_sizes, sizes)]
        )

    def forward(self, x, inference=False):
        if inference:
            for linear in self.layers:
                x = F.relu(linear(x))
                x0 = x[0].unsqueeze(0)
                mask = torch.autograd.Variable(torch.bernoulli(x0.data.new(x0.data.size()).fill_(1 - self.p_dropout)))
                mask = mask.expand(x.size(0), x.size(1))
                x = x * mask * 1 / (1 - self.p_dropout)
        else:
            for linear in self.layers:
                x = F.dropout(F.relu(linear(x)), p=self.p_dropout, training=True)
        return x


class ConditionalLayerNorm(torch.nn.LayerNorm):
    """
    This module is used to condition torch.nn.LayerNorm.
    If we don't have any conditions, this will be a normal LayerNorm.
    """

    def __init__(self, hidden_dim, condition_dim=None, condition_types=[]):
        check_support_condition_types(condition_types)
        self.condition = "layernorm" in condition_types
        super().__init__(hidden_dim, elementwise_affine=not self.condition)

        if self.condition:
            self.cond_weight = torch.nn.Linear(condition_dim, hidden_dim)
            self.cond_bias = torch.nn.Linear(condition_dim, hidden_dim)
            self.init_parameters()

    def init_parameters(self):
        torch.nn.init.constant_(self.cond_weight.weight, 0.0)
        torch.nn.init.constant_(self.cond_weight.bias, 1.0)
        torch.nn.init.constant_(self.cond_bias.weight, 0.0)
        torch.nn.init.constant_(self.cond_bias.bias, 0.0)

    def forward(self, inputs, conditioning=None):
        inputs = super().forward(inputs)

        # Normalize along channel
        if self.condition:
            if conditioning is None:
                raise ValueError(
                    """You should add additional data types as conditions (e.g. speaker id or reference audio) 
                                 and define speaker_encoder in your config."""
                )

            inputs = inputs * self.cond_weight(conditioning)
            inputs = inputs + self.cond_bias(conditioning)

        return inputs


class ConditionalInput(torch.nn.Module):
    """
    This module is used to condition any model inputs.
    If we don't have any conditions, this will be a normal pass.
    """

    def __init__(self, hidden_dim, condition_dim, condition_types=[]):
        check_support_condition_types(condition_types)
        super().__init__()
        self.support_types = ["add", "concat"]
        self.condition_types = [tp for tp in condition_types if tp in self.support_types]
        self.hidden_dim = hidden_dim
        self.condition_dim = condition_dim

        if "add" in self.condition_types and condition_dim != hidden_dim:
            self.add_proj = torch.nn.Linear(condition_dim, hidden_dim)

        if "concat" in self.condition_types:
            self.concat_proj = torch.nn.Linear(hidden_dim + condition_dim, hidden_dim)

    def forward(self, inputs, conditioning=None):
        """
        Args:
            inputs (torch.tensor): B x T x H tensor.
            conditioning (torch.tensor): B x 1 x C conditioning embedding.
        """
        if len(self.condition_types) > 0:
            if conditioning is None:
                raise ValueError(
                    """You should add additional data types as conditions (e.g. speaker id or reference audio) 
                                 and define speaker_encoder in your config."""
                )

            if "add" in self.condition_types:
                if self.condition_dim != self.hidden_dim:
                    conditioning = self.add_proj(conditioning)
                inputs = inputs + conditioning

            if "concat" in self.condition_types:
                conditioning = conditioning.repeat(1, inputs.shape[1], 1)
                inputs = torch.cat([inputs, conditioning], dim=-1)
                inputs = self.concat_proj(inputs)

        return inputs


class StyleAttention(NeuralModule):
    def __init__(self, gst_size=128, n_style_token=10, n_style_attn_head=4):
        super(StyleAttention, self).__init__()

        token_size = gst_size // n_style_attn_head
        self.tokens = torch.nn.Parameter(torch.FloatTensor(n_style_token, token_size))
        self.mha = torch.nn.MultiheadAttention(
            embed_dim=gst_size,
            num_heads=n_style_attn_head,
            dropout=0.0,
            bias=True,
            kdim=token_size,
            vdim=token_size,
            batch_first=True,
        )
        torch.nn.init.normal_(self.tokens)

    @property
    def input_types(self):
        return {
            "inputs": NeuralType(('B', 'D'), EncodedRepresentation()),
            "token_id": NeuralType(('B'), Index(), optional=True),
        }

    @property
    def output_types(self):
        return {
            "style_emb": NeuralType(('B', 'D'), EncodedRepresentation()),
        }

    def forward(self, inputs):
        batch_size = inputs.size(0)
        query = inputs.unsqueeze(1)
        tokens = F.tanh(self.tokens).unsqueeze(0).expand(batch_size, -1, -1)

        style_emb, _ = self.mha(query=query, key=tokens, value=tokens)
        style_emb = style_emb.squeeze(1)
        return style_emb


class Conv2DReLUNorm(torch.nn.Module):
    def __init__(self, in_channels, out_channels, kernel_size=3, stride=2, padding=1, bias=True, dropout=0.0):
        super(Conv2DReLUNorm, self).__init__()
        self.conv = torch.nn.Conv2d(
            in_channels, out_channels, kernel_size=kernel_size, stride=stride, padding=padding, bias=bias
        )
        self.norm = torch.nn.LayerNorm(out_channels)
        self.dropout = torch.nn.Dropout(dropout)

    def forward(self, x, x_mask=None):
        if x_mask is not None:
            x = x * x_mask

        # bhwc -> bchw
        x = x.contiguous().permute(0, 3, 1, 2)
        x = F.relu(self.conv(x))
        # bchw -> bhwc
        x = x.contiguous().permute(0, 2, 3, 1)
        x = self.norm(x)
        x = self.dropout(x)
        return x


class ReferenceEncoder(NeuralModule):
    """
    Encode mel-spectrograms to an utterance level feature
    """

    def __init__(self, n_mels, cnn_filters, dropout, gru_hidden, kernel_size, stride, padding, bias):
        super(ReferenceEncoder, self).__init__()
        self.filter_size = [1] + list(cnn_filters)
        self.layers = torch.nn.ModuleList(
            [
                Conv2DReLUNorm(
                    in_channels=int(self.filter_size[i]),
                    out_channels=int(self.filter_size[i + 1]),
                    kernel_size=kernel_size,
                    stride=stride,
                    padding=padding,
                    bias=bias,
                    dropout=dropout,
                )
                for i in range(len(cnn_filters))
            ]
        )
        post_conv_height = self.calculate_post_conv_lengths(n_mels, n_convs=len(cnn_filters))
        self.gru = torch.nn.GRU(
            input_size=cnn_filters[-1] * post_conv_height,
            hidden_size=gru_hidden,
            batch_first=True,
        )

    @property
    def input_types(self):
        return {
            "inputs": NeuralType(('B', 'D', 'T_spec'), MelSpectrogramType()),
            "inputs_lengths": NeuralType(('B'), LengthsType()),
        }

    @property
    def output_types(self):
        return {
            "out": NeuralType(('B', 'D'), EncodedRepresentation()),
        }

    def forward(self, inputs, inputs_lengths):
        # BMW -> BWMC (M: mels)
        x = inputs.transpose(1, 2).unsqueeze(3)
        x_lens = inputs_lengths
        x_masks = self.lengths_to_masks(x_lens).unsqueeze(2).unsqueeze(3)

        for layer in self.layers:
            x = layer(x, x_masks)
            x_lens = self.calculate_post_conv_lengths(x_lens)
            x_masks = self.lengths_to_masks(x_lens).unsqueeze(2).unsqueeze(3)

        # BWMC -> BWC
        x = x.contiguous().view(x.shape[0], x.shape[1], -1)

        self.gru.flatten_parameters()
        packed_x = pack_padded_sequence(x, x_lens.cpu(), batch_first=True, enforce_sorted=False)
        packed_x, _ = self.gru(packed_x)
        x, x_lens = pad_packed_sequence(packed_x, batch_first=True)
        x = x[torch.arange(len(x_lens)), (x_lens - 1), :]
        return x

    @staticmethod
    def calculate_post_conv_lengths(lengths, n_convs=1, kernel_size=3, stride=2, pad=1):
        """Batch lengths after n convolution with fixed kernel/stride/pad."""
        for _ in range(n_convs):
            lengths = (lengths - kernel_size + 2 * pad) // stride + 1
        return lengths

    @staticmethod
    def lengths_to_masks(lengths):
        """Batch of lengths to batch of masks"""
        # B -> BxT
        masks = torch.arange(lengths.max()).to(lengths.device).expand(
            lengths.shape[0], lengths.max()
        ) < lengths.unsqueeze(1)
        return masks


class GlobalStyleToken(NeuralModule):
    """
    Global Style Token based Speaker Embedding
    """

    def __init__(
        self,
        reference_encoder,
        gst_size=128,
        n_style_token=10,
        n_style_attn_head=4,
    ):
        super(GlobalStyleToken, self).__init__()
        self.reference_encoder = reference_encoder
        self.style_attention = StyleAttention(
            gst_size=gst_size, n_style_token=n_style_token, n_style_attn_head=n_style_attn_head
        )

    @property
    def input_types(self):
        return {
            "inp": NeuralType(('B', 'D', 'T_spec'), MelSpectrogramType()),
            "inp_lengths": NeuralType(('B'), LengthsType()),
        }

    @property
    def output_types(self):
        return {
            "gst": NeuralType(('B', 'D'), EncodedRepresentation()),
        }

    def forward(self, inp, inp_lengths):
        style_embedding = self.reference_encoder(inp, inp_lengths)
        gst = self.style_attention(style_embedding)
        return gst


class SpeakerLookupTable(torch.nn.Module):
    """
    LookupTable based Speaker Embedding
    """

    def __init__(self, n_speakers, embedding_dim):
        super(SpeakerLookupTable, self).__init__()
        self.table = torch.nn.Embedding(n_speakers, embedding_dim)

    def forward(self, speaker):
        return self.table(speaker)


class SpeakerEncoder(NeuralModule):
    """
    class SpeakerEncoder represents speakers representation.
    This module can combine GST (global style token) based speaker embeddings and lookup table speaker embeddings.
    """

    def __init__(self, lookup_module=None, gst_module=None, precomputed_embedding_dim=None):
        """
        lookup_module: Torch module to get lookup based speaker embedding
        gst_module: Neural module to get GST based speaker embedding
        precomputed_embedding_dim: Give precomputed speaker embedding dimension to use precompute speaker embedding
        """
        super(SpeakerEncoder, self).__init__()

        # Multi-speaker embedding
        self.lookup_module = lookup_module

        # Reference speaker embedding
        self.gst_module = gst_module

        if precomputed_embedding_dim is not None:
            self.precomputed_emb = torch.nn.Parameter(torch.empty(precomputed_embedding_dim))
        else:
            self.precomputed_emb = None

    @property
    def input_types(self):
        return {
            "batch_size": NeuralType(optional=True),
            "speaker": NeuralType(('B'), Index(), optional=True),
            "reference_spec": NeuralType(('B', 'D', 'T_spec'), MelSpectrogramType(), optional=True),
            "reference_spec_lens": NeuralType(('B'), LengthsType(), optional=True),
        }

    @property
    def output_types(self):
        return {
            "embs": NeuralType(('B', 'D'), EncodedRepresentation()),
        }

    def overwrite_precomputed_emb(self, emb):
        self.precomputed_emb = torch.nn.Parameter(emb)

    def forward(self, batch_size=None, speaker=None, reference_spec=None, reference_spec_lens=None):
        embs = None

        # Get Precomputed speaker embedding
        if self.precomputed_emb is not None:
            return self.precomputed_emb.unsqueeze(0).repeat(batch_size, 1)

        # Get Lookup table speaker embedding
        if self.lookup_module is not None and speaker is not None:
            embs = self.lookup_module(speaker)

        # Get GST based speaker embedding
        if reference_spec is not None and reference_spec_lens is not None:
            if self.gst_module is not None:
                out = self.gst_module(reference_spec, reference_spec_lens)
                embs = out if embs is None else embs + out
            else:
                logging.warning("You may add `gst_module` in speaker_encoder to use reference_audio.")

        return embs