# Adapted from fishaudio/fish-speech, revision 1ff3c3ed2f80d3106a83909dd25b83129c3d816f.
# Copyright Fish Audio contributors. See LICENSE_FISH_AUDIO for the upstream license.
import math
from functools import partial
from shared import attention_kit
import typing as tp
from dataclasses import dataclass
from typing import List, Optional, Union

import numpy as np
import torch
from .codec_primitives import Snake1d, WNConv1d, WNConvTranspose1d
from torch import Tensor, nn
from torch.nn import functional as F
def weight_norm(module, name="weight", dim=0):
    return module  # folded into the prepared checkpoint
from torch.nn.utils.parametrize import remove_parametrizations


@dataclass
class VQResult:
    z: torch.Tensor
    codes: torch.Tensor
    latents: torch.Tensor
    codebook_loss: torch.Tensor
    commitment_loss: torch.Tensor
    semantic_distill_z: torch.Tensor | None = None


def find_multiple(n: int, k: int) -> int:
    if n % k == 0:
        return n
    return n + k - (n % k)


@dataclass
class ModelArgs:
    block_size: int = 2048
    n_layer: int = 8
    n_head: int = 8
    dim: int = 512
    intermediate_size: int = 1536
    n_local_heads: int = -1
    head_dim: int = 64
    rope_base: float = 10000
    norm_eps: float = 1e-5
    dropout_rate: float = 0.1
    attn_dropout_rate: float = 0.1
    channels_first: bool = True  # to be compatible with conv1d input/output
    pos_embed_type: str = "rope"  # can be "rope" or "conformer"
    max_relative_position: int = 128  # for conformer-style relative position embedding
    window_size: int = 512  # for window limited attention

    def __post_init__(self):
        if self.n_local_heads == -1:
            self.n_local_heads = self.n_head
        if self.intermediate_size is None:
            hidden_dim = 4 * self.dim
            n_hidden = int(2 * hidden_dim / 3)
            self.intermediate_size = find_multiple(n_hidden, 256)
        assert self.pos_embed_type in [
            "rope",
            "conformer",
        ], "pos_embed_type must be either 'rope' or 'conformer'"


class KVCache(nn.Module):
    def __init__(
        self, max_batch_size, max_seq_length, n_heads, head_dim, dtype=torch.bfloat16
    ):
        super().__init__()
        cache_shape = (max_batch_size, n_heads, max_seq_length, head_dim)
        self.register_buffer("k_cache", torch.zeros(cache_shape, dtype=dtype))
        self.register_buffer("v_cache", torch.zeros(cache_shape, dtype=dtype))

    def update(self, input_pos, k_val, v_val):
        # input_pos: [S], k_val: [B, H, S, D]
        assert input_pos.shape[0] == k_val.shape[2]

        k_out = self.k_cache
        v_out = self.v_cache
        k_out[:, :, input_pos] = k_val
        v_out[:, :, input_pos] = v_val

        return (
            k_out[:, :, : input_pos.max() + 1, :],
            v_out[:, :, : input_pos.max() + 1, :],
        )

    def clear_cache(self, prompt_len):
        self.k_cache[:, :, prompt_len:, :] = torch.zeros_like(
            self.k_cache[:, :, prompt_len:, :]
        )
        self.v_cache[:, :, prompt_len:, :] = torch.zeros_like(
            self.v_cache[:, :, prompt_len:, :]
        )


class Transformer(nn.Module):
    def __init__(self, config: ModelArgs) -> None:
        super().__init__()
        self.config = config

        self.layers = nn.ModuleList(
            TransformerBlock(config) for _ in range(config.n_layer)
        )
        self.norm = RMSNorm(config.dim, eps=config.norm_eps)

        self.max_batch_size = -1
        self.max_seq_length = -1
        self.use_kv_cache = False

    def setup_caches(self, max_batch_size, max_seq_length):
        """
        This method will only be called during inference when using KV cache.
        """
        head_dim = self.config.dim // self.config.n_head
        max_seq_length = find_multiple(max_seq_length, 8)
        self.max_seq_length = max_seq_length
        self.max_batch_size = max_batch_size
        dtype = self.norm.weight.dtype
        device = self.norm.weight.device

        for b in self.layers:
            b.attention.kv_cache = KVCache(
                max_batch_size,
                max_seq_length,
                self.config.n_local_heads,
                head_dim,
                dtype,
            ).to(device)

        self.use_kv_cache = True

    def forward(
        self,
        x: Tensor,
        input_pos: Optional[Tensor] = None,
        mask: Optional[Tensor] = None,
    ) -> Tensor:
        if self.config.pos_embed_type == "rope":
            freqs_cis = precompute_freqs_cis(x.shape[1], self.config.head_dim, self.config.rope_base, device=x.device)
        else:
            freqs_cis = None

        if mask is None:
            positions = torch.arange(x.shape[1], device=x.device)
            mask = (positions[:, None] >= positions[None, :])[None, None]

        for i, layer in enumerate(self.layers):
            x = layer(x, input_pos, freqs_cis, mask)
        x = self.norm(x)
        return x


class TransformerBlock(nn.Module):
    def __init__(self, config: ModelArgs) -> None:
        super().__init__()
        self.attention = Attention(config)
        self.feed_forward = FeedForward(config)
        self.ffn_norm = RMSNorm(config.dim, eps=config.norm_eps)
        self.attention_norm = RMSNorm(config.dim, eps=config.norm_eps)
        self.attention_layer_scale = LayerScale(config.dim, inplace=True)
        self.ffn_layer_scale = LayerScale(config.dim, inplace=True)

    def forward(
        self,
        x: Tensor,
        input_pos: Tensor,
        freqs_cis: Tensor,
        mask: Tensor,
    ) -> Tensor:
        h = x + self.attention_layer_scale(
            self.attention(self.attention_norm(x), freqs_cis, mask, input_pos)
        )
        out = h + self.ffn_layer_scale(self.feed_forward(self.ffn_norm(h)))
        return out


class Attention(nn.Module):
    def __init__(self, config: ModelArgs):
        super().__init__()
        assert config.dim % config.n_head == 0

        total_head_dim = (config.n_head + 2 * config.n_local_heads) * config.head_dim
        # key, query, value projections for all heads, but in a batch
        self.wq = nn.Linear(config.dim, config.n_head * config.head_dim, bias=False)
        self.wk = nn.Linear(config.dim, config.n_local_heads * config.head_dim, bias=False)
        self.wv = nn.Linear(config.dim, config.n_local_heads * config.head_dim, bias=False)
        self.wo = nn.Linear(config.head_dim * config.n_head, config.dim, bias=False)
        self.kv_cache = None

        self.n_head = config.n_head
        self.head_dim = config.head_dim
        self.n_local_heads = config.n_local_heads
        self.dim = config.dim
        self.attn_dropout_rate = config.attn_dropout_rate
        self.pos_embed_type = config.pos_embed_type

        # Add relative position embedding for conformer-style
        if self.pos_embed_type == "conformer":
            self.max_relative_position = config.max_relative_position
            num_pos_embeddings = 2 * config.max_relative_position + 1
            self.rel_pos_embeddings = nn.Parameter(
                torch.zeros(num_pos_embeddings, self.head_dim)
            )
            nn.init.normal_(self.rel_pos_embeddings, mean=0.0, std=0.02)

    def _compute_conformer_pos_scores(self, q: Tensor, seqlen: int) -> Tensor:
        # q: [B, H, S, D]
        # Returns: [B, H, S, S]
        positions = torch.arange(seqlen, device=q.device)
        relative_positions = positions.unsqueeze(1) - positions.unsqueeze(0)  # [S, S]
        relative_positions = torch.clamp(
            relative_positions + self.max_relative_position,
            0,
            2 * self.max_relative_position,
        )
        rel_embeddings = self.rel_pos_embeddings[relative_positions]  # [S, S, D]

        # Compute attention scores with relative position embeddings
        q = q.transpose(1, 2)  # [B, S, H, D]
        rel_logits = torch.matmul(q, rel_embeddings.transpose(-2, -1))  # [B, S, H, S]
        rel_logits = rel_logits.transpose(1, 2)  # [B, H, S, S]
        return rel_logits

    def forward(
        self,
        x: Tensor,
        freqs_cis: Tensor,
        mask: Tensor,
        input_pos: Optional[Tensor] = None,
    ) -> Tensor:
        if self.pos_embed_type != "rope" or self.kv_cache is not None:
            raise ValueError("Fish codec uses uncached RoPE attention")
        def rotate(query, key, group):
            for tensor in (query, key):
                if tensor is not None:
                    attention_kit.rows_(tensor, lambda part, first, last: apply_rotary_emb(part, freqs_cis[first:last]))
        output = attention_kit.qkv_attention([x], self.wq, self.wk, self.wv, self.n_head, self.head_dim, rotate,
                                            kv_heads=self.n_local_heads, attention_mask=mask.transpose(1, 2))
        return self.wo(output.reshape(x.shape[0], x.shape[1], -1))


class FeedForward(nn.Module):
    def __init__(self, config: ModelArgs) -> None:
        super().__init__()
        self.w1 = nn.Linear(config.dim, config.intermediate_size, bias=False)
        self.w3 = nn.Linear(config.dim, config.intermediate_size, bias=False)
        self.w2 = nn.Linear(config.intermediate_size, config.dim, bias=False)
        self.dropout = nn.Dropout(config.dropout_rate)

    def forward(self, x: Tensor) -> Tensor:
        return self.w2(self.dropout(F.silu(self.w1(x)) * self.w3(x)))


class RMSNorm(nn.Module):
    def __init__(self, dim: int, eps: float = 1e-5):
        super().__init__()
        self.eps = eps
        self.weight = nn.Parameter(torch.ones(dim))

    def _norm(self, x):
        return x * torch.rsqrt(torch.mean(x * x, dim=-1, keepdim=True) + self.eps)

    def forward(self, x: Tensor) -> Tensor:
        output = self._norm(x.float()).type_as(x)
        return output * self.weight


class LayerScale(nn.Module):
    def __init__(
        self,
        dim: int,
        init_values: Union[float, Tensor] = 1e-2,
        inplace: bool = False,
    ) -> None:
        super().__init__()
        self.inplace = inplace
        self.gamma = nn.Parameter(init_values * torch.ones(dim))

    def forward(self, x: Tensor) -> Tensor:
        return x.mul_(self.gamma) if self.inplace else x * self.gamma


class WindowLimitedTransformer(Transformer):
    """
    Transformer with window limited attention, causal.
    """

    def __init__(
        self,
        config: ModelArgs,
        input_dim: int = 512,
        window_size: Optional[int] = None,
        causal: bool = True,
        look_ahead_conv: nn.Module = None,
    ):
        super().__init__(config)
        self.window_size = window_size
        self.causal = causal
        self.channels_first = config.channels_first
        self.look_ahead_conv = (
            look_ahead_conv if look_ahead_conv is not None else nn.Identity()
        )
        self.input_proj = (
            nn.Linear(input_dim, config.dim)
            if input_dim != config.dim
            else nn.Identity()
        )
        self.output_proj = (
            nn.Linear(config.dim, input_dim)
            if input_dim != config.dim
            else nn.Identity()
        )

    def make_window_limited_mask(
        self,
        max_length: int,
        x_lens: Optional[Tensor] = None,
        device="cpu",
    ) -> Tensor:
        """
        Make mask to form window limited attention.
        """
        if self.causal:
            mask = torch.tril(torch.ones(max_length, max_length, device=device))
            row_indices = torch.arange(max_length, device=device).view(-1, 1)
            window_size = self.window_size or max_length
            valid_range = (row_indices - window_size + 1).clamp(min=0)
            column_indices = torch.arange(max_length, device=device)
            mask = (column_indices >= valid_range) & mask.bool()
        else:
            raise NotImplementedError
        mask = mask.bool()[None, None]
        return mask

    def make_mask(
        self,
        max_length: int,
        x_lens: Optional[Tensor] = None,
        device="cpu",
    ) -> Tensor:
        """
        Make ordinary mask if window size is not specified.
        """
        if self.causal:
            mask = torch.tril(torch.ones(max_length, max_length, device=device))
        else:
            mask = torch.ones(max_length, max_length, device=device)
            mask = mask.bool()[None, None]
            for i, x_len in enumerate(x_lens):
                mask[:x_len, i] = 0
        mask = mask.bool()[None, None]
        return mask

    def forward(
        self,
        x: Tensor,
        x_lens: Optional[Tensor] = None,
    ) -> Tensor:
        if self.channels_first:
            x = x.transpose(1, 2)
        x = self.input_proj(x)  # (B, T, D)
        x = self.look_ahead_conv(x)
        input_pos = torch.arange(x.shape[1], device=x.device)
        # construct mask to form window limited attention
        max_length = x.shape[1]
        if self.window_size is not None:
            mask = self.make_window_limited_mask(max_length, x_lens, device=x.device)
        else:
            mask = self.make_mask(max_length, x_lens, device=x.device)
        mask = mask.to(x.device)
        x = super().forward(x, input_pos, mask)
        x = self.output_proj(x)  # (B, T, D)
        if self.channels_first:
            x = x.transpose(1, 2)
        return x


def precompute_freqs_cis(
    seq_len: int, n_elem: int, base: int = 10000, dtype: torch.dtype = torch.bfloat16, device="cpu"
) -> Tensor:
    freqs = 1.0 / (
        base ** (torch.arange(0, n_elem, 2, device=device)[: (n_elem // 2)].float() / n_elem)
    )
    t = torch.arange(seq_len, device=freqs.device)
    freqs = torch.outer(t, freqs)
    freqs_cis = torch.polar(torch.ones_like(freqs), freqs)
    cache = torch.stack([freqs_cis.real, freqs_cis.imag], dim=-1)
    return cache.to(dtype=dtype)


def apply_rotary_emb(x: Tensor, freqs_cis: Tensor) -> Tensor:
    xshaped = x.float().reshape(*x.shape[:-1], -1, 2)
    freqs_cis = freqs_cis.view(1, xshaped.size(1), 1, xshaped.size(3), 2)
    x_out2 = torch.stack(
        [
            xshaped[..., 0] * freqs_cis[..., 0] - xshaped[..., 1] * freqs_cis[..., 1],
            xshaped[..., 1] * freqs_cis[..., 0] + xshaped[..., 0] * freqs_cis[..., 1],
        ],
        -1,
    )

    x_out2 = x_out2.flatten(3)
    return x_out2.type_as(x)


def init_weights(m):
    if isinstance(m, nn.Conv1d):
        nn.init.trunc_normal_(m.weight, std=0.02)
        nn.init.constant_(m.bias, 0)


def unpad1d(x: torch.Tensor, paddings: tp.Tuple[int, int]):
    """Remove padding from x, handling properly zero padding. Only for 1d!"""
    padding_left, padding_right = paddings
    assert padding_left >= 0 and padding_right >= 0, (padding_left, padding_right)
    assert (padding_left + padding_right) <= x.shape[-1]
    end = x.shape[-1] - padding_right
    return x[..., padding_left:end]


def get_extra_padding_for_conv1d(
    x: torch.Tensor, kernel_size: int, stride: int, padding_total: int = 0
) -> int:
    """See `pad_for_conv1d`."""
    length = x.shape[-1]
    n_frames = (length - kernel_size + padding_total) / stride + 1
    ideal_length = (math.ceil(n_frames) - 1) * stride + (kernel_size - padding_total)
    return ideal_length - length


def pad1d(
    x: torch.Tensor,
    paddings: tp.Tuple[int, int],
    mode: str = "zeros",
    value: float = 0.0,
):
    """Tiny wrapper around F.pad, just to allow for reflect padding on small input.
    If this is the case, we insert extra 0 padding to the right
    before the reflection happen.
    """
    length = x.shape[-1]
    padding_left, padding_right = paddings
    assert padding_left >= 0 and padding_right >= 0, (padding_left, padding_right)
    if mode == "reflect":
        max_pad = max(padding_left, padding_right)
        extra_pad = 0
        if length <= max_pad:
            extra_pad = max_pad - length + 1
            x = F.pad(x, (0, extra_pad))
        padded = F.pad(x, paddings, mode, value)
        end = padded.shape[-1] - extra_pad
        return padded[..., :end]
    else:
        return F.pad(x, paddings, mode, value)


class CausalConvNet(nn.Module):
    def __init__(
        self,
        in_channels,
        out_channels,
        kernel_size,
        dilation=1,
        stride=1,
        groups=1,
        padding=None,
    ):
        super(CausalConvNet, self).__init__()
        self.conv = nn.Conv1d(
            in_channels,
            out_channels,
            kernel_size,
            stride=stride,
            dilation=dilation,
            groups=groups,
        )
        self.stride = stride
        self.kernel_size = (kernel_size - 1) * dilation + 1
        self.dilation = dilation
        self.padding = self.kernel_size - self.stride

    def forward(self, x):
        pad = self.padding
        extra_padding = get_extra_padding_for_conv1d(
            x, self.kernel_size, self.stride, pad
        )
        x = pad1d(x, (pad, extra_padding), mode="constant", value=0)
        return self.conv(x).contiguous()

    def weight_norm(self, name="weight", dim=0):
        self.conv = weight_norm(self.conv, name=name, dim=dim)
        return self

    def remove_weight_norm(self):
        self.conv = remove_parametrizations(self.conv)
        return self


class CausalTransConvNet(nn.Module):
    def __init__(
        self, in_channels, out_channels, kernel_size, dilation=1, stride=1, padding=None
    ):
        super(CausalTransConvNet, self).__init__()
        self.conv = nn.ConvTranspose1d(
            in_channels, out_channels, kernel_size, stride=stride, dilation=dilation
        )
        self.stride = stride
        self.kernel_size = kernel_size

    def forward(self, x):
        x = self.conv(x)
        pad = self.kernel_size - self.stride
        padding_right = math.ceil(pad)
        padding_left = pad - padding_right
        x = unpad1d(x, (padding_left, padding_right))
        return x.contiguous()

    def weight_norm(self, name="weight", dim=0):
        self.conv = weight_norm(self.conv, name=name, dim=dim)
        return self

    def remove_weight_norm(self):
        self.conv = remove_parametrizations(self.conv)
        return self


def CausalWNConv1d(*args, **kwargs):
    return CausalConvNet(*args, **kwargs).weight_norm()


def CausalWNConvTranspose1d(*args, **kwargs):
    return CausalTransConvNet(*args, **kwargs).weight_norm()


class ResidualUnit(nn.Module):
    def __init__(self, dim: int = 16, dilation: int = 1, causal: bool = False):
        super().__init__()
        conv_class = CausalWNConv1d if causal else WNConv1d
        pad = ((7 - 1) * dilation) // 2
        self.block = nn.Sequential(
            Snake1d(dim),
            conv_class(dim, dim, kernel_size=7, dilation=dilation, padding=pad),
            Snake1d(dim),
            conv_class(dim, dim, kernel_size=1),
        )
        self.causal = causal

    def forward(self, x):
        y = self.block(x)
        pad = x.shape[-1] - y.shape[-1]
        if pad > 0:
            if self.causal:
                x = x[..., :-pad]
            else:
                x = x[..., pad // 2 : -pad // 2]
        return x + y


class EncoderBlock(nn.Module):
    def __init__(
        self,
        dim: int = 16,
        stride: int = 1,
        causal: bool = False,
        n_t_layer: int = 0,
        transformer_general_config=None,
    ):
        super().__init__()
        conv_class = CausalWNConv1d if causal else WNConv1d
        transformer_module = (
            nn.Identity()
            if n_t_layer == 0
            else (
                WindowLimitedTransformer(
                    causal=causal,
                    input_dim=dim,
                    window_size=getattr(transformer_general_config, "window_size", 512),
                    config=transformer_general_config(
                        n_layer=n_t_layer,
                        n_head=dim // 64,
                        dim=dim,
                        intermediate_size=dim * 3,
                    ),
                )
            )
        )
        self.block = nn.Sequential(
            ResidualUnit(dim // 2, dilation=1, causal=causal),
            ResidualUnit(dim // 2, dilation=3, causal=causal),
            ResidualUnit(dim // 2, dilation=9, causal=causal),
            Snake1d(dim // 2),
            conv_class(
                dim // 2,
                dim,
                kernel_size=2 * stride,
                stride=stride,
                padding=math.ceil(stride / 2),
            ),
            transformer_module,
        )

    def forward(self, x):
        return self.block(x)


class Encoder(nn.Module):
    def __init__(
        self,
        d_model: int = 64,
        strides: list = [2, 4, 8, 8],
        d_latent: int = 64,
        n_transformer_layers: list = [0, 0, 4, 4],
        transformer_general_config: ModelArgs = None,
        causal: bool = False,
    ):
        super().__init__()
        conv_class = CausalWNConv1d if causal else WNConv1d
        # Create first convolution
        self.block = [conv_class(1, d_model, kernel_size=7, padding=3)]

        # Create EncoderBlocks that double channels as they downsample by `stride`
        for stride, n_t_layer in zip(strides, n_transformer_layers):
            d_model *= 2
            self.block += [
                EncoderBlock(
                    d_model,
                    stride=stride,
                    causal=causal,
                    n_t_layer=n_t_layer,
                    transformer_general_config=transformer_general_config,
                )
            ]

        # Create last convolution
        self.block += [
            Snake1d(d_model),
            conv_class(d_model, d_latent, kernel_size=3, padding=1),
        ]

        # Wrap black into nn.Sequential
        self.block = nn.Sequential(*self.block)
        self.enc_dim = d_model

    def forward(self, x):
        return self.block(x)


class DecoderBlock(nn.Module):
    def __init__(
        self,
        input_dim: int = 16,
        output_dim: int = 8,
        stride: int = 1,
        causal: bool = False,
        n_t_layer: int = 0,
        transformer_general_config=None,
    ):
        super().__init__()
        conv_trans_class = CausalWNConvTranspose1d if causal else WNConvTranspose1d
        transformer_module = (
            nn.Identity()
            if n_t_layer == 0
            else (
                WindowLimitedTransformer(
                    causal=causal,
                    input_dim=input_dim,
                    window_size=None,
                    config=transformer_general_config(
                        n_layer=n_t_layer,
                        n_head=input_dim // 64,
                        dim=input_dim,
                        intermediate_size=input_dim * 3,
                    ),
                )
            )
        )
        self.block = nn.Sequential(
            # transformer_module,
            Snake1d(input_dim),
            conv_trans_class(
                input_dim,
                output_dim,
                kernel_size=2 * stride,
                stride=stride,
                padding=math.ceil(stride / 2),
            ),
            ResidualUnit(output_dim, dilation=1, causal=causal),
            ResidualUnit(output_dim, dilation=3, causal=causal),
            ResidualUnit(output_dim, dilation=9, causal=causal),
        )

    def forward(self, x):
        return self.block(x)


class Decoder(nn.Module):
    def __init__(
        self,
        input_channel,
        channels,
        rates,
        d_out: int = 1,
        causal: bool = False,
        n_transformer_layers: list = [0, 0, 0, 0],
        transformer_general_config=None,
    ):
        super().__init__()
        conv_class = CausalWNConv1d if causal else WNConv1d
        # Add first conv layer
        layers = [conv_class(input_channel, channels, kernel_size=7, padding=3)]

        # Add upsampling + MRF blocks
        for i, (stride, n_t_layer) in enumerate(zip(rates, n_transformer_layers)):
            input_dim = channels // 2**i
            output_dim = channels // 2 ** (i + 1)
            layers += [
                DecoderBlock(
                    input_dim,
                    output_dim,
                    stride,
                    causal=causal,
                    n_t_layer=n_t_layer,
                    transformer_general_config=transformer_general_config,
                )
            ]

        # Add final conv layer
        layers += [
            Snake1d(output_dim),
            conv_class(output_dim, d_out, kernel_size=7, padding=3),
            nn.Tanh(),
        ]

        self.model = nn.Sequential(*layers)

    def forward(self, x):
        return self.model(x)


class DAC(nn.Module):
    def __init__(
        self,
        encoder_dim: int = 64,
        encoder_rates: List[int] = [2, 4, 8, 8],
        latent_dim: int = None,
        decoder_dim: int = 1536,
        decoder_rates: List[int] = [8, 8, 4, 2],
        quantizer: torch.nn.Module = None,
        sample_rate: int = 44100,
        causal: bool = True,
        encoder_transformer_layers: List[int] = [0, 0, 0, 0],
        decoder_transformer_layers: List[int] = [0, 0, 0, 0],
        overwrite_decoder: torch.nn.Module = None,
        transformer_general_config=None,
    ):
        super().__init__()

        self.encoder_dim = encoder_dim
        self.encoder_rates = encoder_rates
        self.decoder_dim = decoder_dim
        self.decoder_rates = decoder_rates
        self.sample_rate = sample_rate

        if latent_dim is None:
            latent_dim = encoder_dim * (2 ** len(encoder_rates))

        self.latent_dim = latent_dim

        self.hop_length = np.prod(encoder_rates)
        self.encoder = Encoder(
            encoder_dim,
            encoder_rates,
            latent_dim,
            causal=causal,
            n_transformer_layers=encoder_transformer_layers,
            transformer_general_config=transformer_general_config,
        )

        self.quantizer = quantizer

        if overwrite_decoder is not None:
            self.decoder = overwrite_decoder
        else:
            self.decoder = Decoder(
                latent_dim,
                decoder_dim,
                decoder_rates,
                causal=causal,
                n_transformer_layers=decoder_transformer_layers,
                transformer_general_config=transformer_general_config,
            )
        self.sample_rate = sample_rate
        self.apply(init_weights)

        self.delay = 0

        self.frame_length = self.hop_length * 4

    def preprocess(self, audio_data, sample_rate):
        if sample_rate is None:
            sample_rate = self.sample_rate
        assert sample_rate == self.sample_rate

        length = audio_data.shape[-1]
        right_pad = math.ceil(length / self.hop_length) * self.hop_length - length
        audio_data = nn.functional.pad(audio_data, (0, right_pad))

        return audio_data

    def encode(
        self,
        audio_data: torch.Tensor,
        audio_lengths: torch.Tensor = None,
        n_quantizers: int = None,
        **kwargs,
    ):
        """Encode given audio data and return quantized latent codes

        Parameters
        ----------
        audio_data : Tensor[B x T]
            Audio data to encode
        n_quantizers : int, optional
            Number of quantizers to use, by default None
            If None, all quantizers are used.

        Returns
        -------
        dict
            A dictionary with the following keys:
            "z" : Tensor[B x D x T]
                Quantized continuous representation of input
            "codes" : Tensor[B x N x T]
                Codebook indices for each codebook
                (quantized discrete representation of input)
            "latents" : Tensor[B x N*D x T]
                Projected latents (continuous representation of input before quantization)
            "vq/commitment_loss" : Tensor[1]
                Commitment loss to train encoder to predict vectors closer to codebook
                entries
            "vq/codebook_loss" : Tensor[1]
                Codebook loss to update the codebook
            "length" : int
                Number of samples in input audio
        """
        # pad to multiple of self.frame_length
        if audio_data.ndim == 2:
            audio_data = audio_data.unsqueeze(1)
        length = audio_data.shape[-1]
        right_pad = math.ceil(length / self.frame_length) * self.frame_length - length
        audio_data = nn.functional.pad(audio_data, (0, right_pad))
        if audio_lengths is None:
            audio_lengths = torch.tensor([length + right_pad], dtype=torch.long, device=audio_data.device)

        z = self.encoder(audio_data)
        vq_results = self.quantizer(z, n_quantizers, **kwargs)
        indices = vq_results.codes
        indices_lens = torch.ceil(audio_lengths / self.frame_length).long()
        return indices, indices_lens

    def from_indices(self, indices: torch.Tensor):
        z = self.quantizer.decode(indices)
        return self.decoder(z)

    def decode(self, z: torch.Tensor):
        """Decode given latent codes and return audio data

        Parameters
        ----------
        z : Tensor[B x D x T]
            Quantized continuous representation of input
        length : int, optional
            Number of samples in output audio, by default None

        Returns
        -------
        dict
            A dictionary with the following keys:
            "audio" : Tensor[B x 1 x length]
                Decoded audio data.
        """
        return self.decoder(z)

    def forward(self, value, *, encode=False):
        return self.encode(value)[0] if encode else self.from_indices(value)



def create_codec():
    from .codec_rvq import DownsampleResidualVectorQuantize
    transformer = lambda: WindowLimitedTransformer(ModelArgs(block_size=2048, n_layer=8, n_head=16, dim=1024, intermediate_size=3072), input_dim=1024, window_size=128, causal=True)
    quantizer = DownsampleResidualVectorQuantize(input_dim=1024, n_codebooks=9, codebook_size=1024, codebook_dim=8,
        downsample_factor=(2, 2), semantic_codebook_size=4096, pre_module=transformer(), post_module=transformer())
    return DAC(encoder_dim=64, encoder_rates=[2, 4, 8, 8], decoder_dim=1536, decoder_rates=[8, 8, 4, 2], sample_rate=44100,
        encoder_transformer_layers=[0, 0, 0, 4], decoder_transformer_layers=[0, 0, 0, 0], quantizer=quantizer,
        transformer_general_config=partial(ModelArgs, block_size=8192))
