from typing import *
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.utils.checkpoint
from ...modules.utils import convert_module_to_f16, convert_module_to_f32, zero_module
from ...modules import sparse as sp
from ...modules.norm import LayerNorm32


class SparseResBlock3d(nn.Module):
    def __init__(
        self,
        channels: int,
        out_channels: Optional[int] = None,
        downsample: bool = False,
        upsample: bool = False,
        resample_mode: Literal['nearest', 'spatial2channel'] = 'nearest',
        use_checkpoint: bool = False,
    ):
        super().__init__()
        self.channels = channels
        self.out_channels = out_channels or channels
        self.downsample = downsample
        self.upsample = upsample
        self.resample_mode = resample_mode
        self.use_checkpoint = use_checkpoint
        
        assert not (downsample and upsample), "Cannot downsample and upsample at the same time"

        self.norm1 = LayerNorm32(channels, elementwise_affine=True, eps=1e-6)
        self.norm2 = LayerNorm32(self.out_channels, elementwise_affine=False, eps=1e-6)
        if resample_mode == 'nearest':
            self.conv1 = sp.SparseConv3d(channels, self.out_channels, 3)
        elif resample_mode =='spatial2channel' and not self.downsample:
            self.conv1 = sp.SparseConv3d(channels, self.out_channels * 8, 3)
        elif resample_mode =='spatial2channel' and self.downsample:
            self.conv1 = sp.SparseConv3d(channels, self.out_channels // 8, 3)
        self.conv2 = zero_module(sp.SparseConv3d(self.out_channels, self.out_channels, 3))
        if resample_mode == 'nearest':
            self.skip_connection = sp.SparseLinear(channels, self.out_channels) if channels != self.out_channels else nn.Identity()
        elif resample_mode =='spatial2channel' and self.downsample:
            self.skip_connection = lambda x: x.replace(x.feats.reshape(x.feats.shape[0], out_channels, channels * 8 // out_channels).mean(dim=-1))
        elif resample_mode =='spatial2channel' and not self.downsample:
            self.skip_connection = lambda x: x.replace(x.feats.repeat_interleave(out_channels // (channels // 8), dim=1))
        self.updown = None
        if self.downsample:
            if resample_mode == 'nearest':
                self.updown = sp.SparseDownsample(2)
            elif resample_mode =='spatial2channel':
                self.updown = sp.SparseSpatial2Channel(2)
        elif self.upsample:
            self.to_subdiv = sp.SparseLinear(channels, 8)
            if resample_mode == 'nearest':
                self.updown = sp.SparseUpsample(2)
            elif resample_mode =='spatial2channel':
                self.updown = sp.SparseChannel2Spatial(2)

    def _updown(self, x: sp.SparseTensor, subdiv: sp.SparseTensor = None) -> sp.SparseTensor:
        if self.downsample:
            x = self.updown(x)
        elif self.upsample:
            x = self.updown(x, subdiv.replace(subdiv.feats > 0))
        return x

    def _forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        subdiv = None
        if self.upsample:
            subdiv = self.to_subdiv(x)
        h = x.replace(self.norm1(x.feats))
        h = h.replace(F.silu(h.feats))
        if self.resample_mode == 'spatial2channel':
            h = self.conv1(h)
        h = self._updown(h, subdiv)
        x = self._updown(x, subdiv)
        if self.resample_mode == 'nearest':
            h = self.conv1(h)
        h = h.replace(self.norm2(h.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv2(h)
        h = h + self.skip_connection(x)
        if self.upsample:
            return h, subdiv
        return h
    
    def forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        if self.use_checkpoint:
            return torch.utils.checkpoint.checkpoint(self._forward, x, use_reentrant=False)
        else:
            return self._forward(x)


class SparseResBlockDownsample3d(nn.Module):
    def __init__(
        self,
        channels: int,
        out_channels: Optional[int] = None,
        use_checkpoint: bool = False,
    ):
        super().__init__()
        self.channels = channels
        self.out_channels = out_channels or channels
        self.use_checkpoint = use_checkpoint
        
        self.norm1 = LayerNorm32(channels, elementwise_affine=True, eps=1e-6)
        self.norm2 = LayerNorm32(self.out_channels, elementwise_affine=False, eps=1e-6)
        self.conv1 = sp.SparseConv3d(channels, self.out_channels, 3)
        self.conv2 = zero_module(sp.SparseConv3d(self.out_channels, self.out_channels, 3))
        self.skip_connection = sp.SparseLinear(channels, self.out_channels) if channels != self.out_channels else nn.Identity()
        self.updown = sp.SparseDownsample(2)

    def _forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        h = x.replace(self.norm1(x.feats))
        h = h.replace(F.silu(h.feats))
        h = self.updown(h)
        x = self.updown(x)
        h = self.conv1(h)
        h = h.replace(self.norm2(h.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv2(h)
        h = h + self.skip_connection(x)
        return h
    
    def forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        if self.use_checkpoint:
            return torch.utils.checkpoint.checkpoint(self._forward, x, use_reentrant=False)
        else:
            return self._forward(x)


class SparseResBlockUpsample3d(nn.Module):
    def __init__(
        self,
        channels: int,
        out_channels: Optional[int] = None,
        use_checkpoint: bool = False,
        pred_subdiv: bool = True,
    ):
        super().__init__()
        self.channels = channels
        self.out_channels = out_channels or channels
        self.use_checkpoint = use_checkpoint
        self.pred_subdiv = pred_subdiv
        
        self.norm1 = LayerNorm32(channels, elementwise_affine=True, eps=1e-6)
        self.norm2 = LayerNorm32(self.out_channels, elementwise_affine=False, eps=1e-6)
        self.conv1 = sp.SparseConv3d(channels, self.out_channels, 3)
        self.conv2 = zero_module(sp.SparseConv3d(self.out_channels, self.out_channels, 3))
        self.skip_connection = sp.SparseLinear(channels, self.out_channels) if channels != self.out_channels else nn.Identity()
        if self.pred_subdiv:
            self.to_subdiv = sp.SparseLinear(channels, 8)
        self.updown = sp.SparseUpsample(2)

    def _forward(self, x: sp.SparseTensor, subdiv: sp.SparseTensor = None) -> sp.SparseTensor:
        if self.pred_subdiv:
            subdiv = self.to_subdiv(x)
        h = x.replace(self.norm1(x.feats))
        h = h.replace(F.silu(h.feats))
        subdiv_binarized = subdiv.replace(subdiv.feats > 0) if subdiv is not None else None
        h = self.updown(h, subdiv_binarized)
        x = self.updown(x, subdiv_binarized)
        h = self.conv1(h)
        h = h.replace(self.norm2(h.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv2(h)
        h = h + self.skip_connection(x)
        if self.pred_subdiv:
            return h, subdiv
        else:
            return h
    
    def forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        if self.use_checkpoint:
            return torch.utils.checkpoint.checkpoint(self._forward, x, use_reentrant=False)
        else:
            return self._forward(x)


class SparseResBlockS2C3d(nn.Module):
    def __init__(
        self,
        channels: int,
        out_channels: Optional[int] = None,
        use_checkpoint: bool = False,
    ):
        super().__init__()
        self.channels = channels
        self.out_channels = out_channels or channels
        self.use_checkpoint = use_checkpoint
        
        self.norm1 = LayerNorm32(channels, elementwise_affine=True, eps=1e-6)
        self.norm2 = LayerNorm32(self.out_channels, elementwise_affine=False, eps=1e-6)
        self.conv1 = sp.SparseConv3d(channels, self.out_channels // 8, 3)
        self.conv2 = zero_module(sp.SparseConv3d(self.out_channels, self.out_channels, 3))
        self.skip_connection = lambda x: x.replace(x.feats.reshape(x.feats.shape[0], out_channels, channels * 8 // out_channels).mean(dim=-1))
        self.updown = sp.SparseSpatial2Channel(2)

    def _forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        h = x.replace(self.norm1(x.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv1(h)
        h = self.updown(h)
        x = self.updown(x)
        h = h.replace(self.norm2(h.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv2(h)
        h = h + self.skip_connection(x)
        return h
    
    def forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        if self.use_checkpoint:
            return torch.utils.checkpoint.checkpoint(self._forward, x, use_reentrant=False)
        else:
            return self._forward(x)


class SparseResBlockC2S3d(nn.Module):
    def __init__(
        self,
        channels: int,
        out_channels: Optional[int] = None,
        use_checkpoint: bool = False,
        pred_subdiv: bool = True,
    ):
        super().__init__()
        self.channels = channels
        self.out_channels = out_channels or channels
        self.use_checkpoint = use_checkpoint
        self.pred_subdiv = pred_subdiv
        
        self.norm1 = LayerNorm32(channels, elementwise_affine=True, eps=1e-6)
        self.norm2 = LayerNorm32(self.out_channels, elementwise_affine=False, eps=1e-6)
        self.conv1 = sp.SparseConv3d(channels, self.out_channels * 8, 3)
        self.conv2 = zero_module(sp.SparseConv3d(self.out_channels, self.out_channels, 3))
        self.skip_connection = lambda x: x.replace(x.feats.repeat_interleave(out_channels // (channels // 8), dim=1))
        if pred_subdiv:
            self.to_subdiv = sp.SparseLinear(channels, 8)
        self.updown = sp.SparseChannel2Spatial(2)

    def _forward(self, x: sp.SparseTensor, subdiv: sp.SparseTensor = None) -> sp.SparseTensor:
        if self.pred_subdiv:
            subdiv = self.to_subdiv(x)
        h = x.replace(self.norm1(x.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv1(h)
        subdiv_binarized = subdiv.replace(subdiv.feats > 0) if subdiv is not None else None
        h = self.updown(h, subdiv_binarized)
        x = self.updown(x, subdiv_binarized)
        h = h.replace(self.norm2(h.feats))
        h = h.replace(F.silu(h.feats))
        h = self.conv2(h)
        h = h + self.skip_connection(x)
        if self.pred_subdiv:
            return h, subdiv
        else:
            return h
    
    def forward(self, x: sp.SparseTensor, subdiv: sp.SparseTensor = None) -> sp.SparseTensor:
        if self.use_checkpoint:
            return torch.utils.checkpoint.checkpoint(self._forward, x, subdiv, use_reentrant=False)
        else:
            return self._forward(x, subdiv)
        
    
class SparseConvNeXtBlock3d(nn.Module):
    def __init__(
        self,
        channels: int,
        mlp_ratio: float = 4.0,
        use_checkpoint: bool = False,
    ):
        super().__init__()
        self.channels = channels
        self.use_checkpoint = use_checkpoint
        
        self.norm = LayerNorm32(channels, elementwise_affine=True, eps=1e-6)
        self.conv = sp.SparseConv3d(channels, channels, 3)
        self.mlp = nn.Sequential(
            nn.Linear(channels, int(channels * mlp_ratio)),
            nn.SiLU(),
            zero_module(nn.Linear(int(channels * mlp_ratio), channels)),
        )

    def _forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        h = self.conv(x)
        h = h.replace(self.norm(h.feats))
        h = h.replace(self.mlp(h.feats))
        return h + x
    
    def forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        if self.use_checkpoint:
            return torch.utils.checkpoint.checkpoint(self._forward, x, use_reentrant=False)
        else:
            return self._forward(x)


class SparseUnetVaeEncoder(nn.Module):
    """
    Sparse Swin Transformer Unet VAE model.
    """
    def __init__(
        self,
        in_channels: int,
        model_channels: List[int],
        latent_channels: int,
        num_blocks: List[int],
        block_type: List[str],
        down_block_type: List[str],
        block_args: List[Dict[str, Any]],
        use_fp16: bool = False,
    ):
        super().__init__()
        self.in_channels = in_channels
        self.model_channels = model_channels
        self.num_blocks = num_blocks
        self.dtype = torch.float16 if use_fp16 else torch.float32
        self.dtype = torch.float16 if use_fp16 else torch.float32

        self.input_layer = sp.SparseLinear(in_channels, model_channels[0])
        self.to_latent = sp.SparseLinear(model_channels[-1], 2 * latent_channels)
        
        self.blocks = nn.ModuleList([])
        for i in range(len(num_blocks)):
            self.blocks.append(nn.ModuleList([]))
            for j in range(num_blocks[i]):
                self.blocks[-1].append(
                    globals()[block_type[i]](
                        model_channels[i],
                        **block_args[i],
                    )
                )
            if i < len(num_blocks) - 1:
                self.blocks[-1].append(
                    globals()[down_block_type[i]](
                        model_channels[i],
                        model_channels[i+1],
                        **block_args[i],
                    )
                )
                
        self.initialize_weights()
        if use_fp16:
            self.convert_to_fp16()

    @property
    def device(self) -> torch.device:
        """
        Return the device of the model.
        """
        return next(self.parameters()).device

    def convert_to_fp16(self) -> None:
        """
        Convert the torso of the model to float16.
        """
        self.blocks.apply(convert_module_to_f16)

    def convert_to_fp32(self) -> None:
        """
        Convert the torso of the model to float32.
        """
        self.blocks.apply(convert_module_to_f32)

    def initialize_weights(self) -> None:
        # Initialize transformer layers:
        def _basic_init(module):
            if isinstance(module, nn.Linear):
                torch.nn.init.xavier_uniform_(module.weight)
                if module.bias is not None:
                    nn.init.constant_(module.bias, 0)
        self.apply(_basic_init)

    def forward(self, x: sp.SparseTensor, sample_posterior=False, return_raw=False):
        h = self.input_layer(x)
        h = h.type(self.dtype)
        for i, res in enumerate(self.blocks):
            for j, block in enumerate(res):
                h = block(h)
        h = h.type(x.dtype)
        h = h.replace(F.layer_norm(h.feats, h.feats.shape[-1:]))
        h = self.to_latent(h)
        
        # Sample from the posterior distribution
        mean, logvar = h.feats.chunk(2, dim=-1)
        if sample_posterior:
            std = torch.exp(0.5 * logvar)
            z = mean + std * torch.randn_like(std)
        else:
            z = mean
        z = h.replace(z)
            
        if return_raw:
            return z, mean, logvar
        else:
            return z
    
    
class SparseUnetVaeDecoder(nn.Module):
    """
    Sparse Swin Transformer Unet VAE model.
    """
    def __init__(
        self,
        out_channels: int,
        model_channels: List[int],
        latent_channels: int,
        num_blocks: List[int],
        block_type: List[str],
        up_block_type: List[str],
        block_args: List[Dict[str, Any]],
        use_fp16: bool = False,
        pred_subdiv: bool = True,
    ):
        super().__init__()
        self.out_channels = out_channels
        self.model_channels = model_channels
        self.num_blocks = num_blocks
        self.use_fp16 = use_fp16
        self.pred_subdiv = pred_subdiv
        self.dtype = torch.float16 if use_fp16 else torch.float32
        self.low_vram = False
        
        self.output_layer = sp.SparseLinear(model_channels[-1], out_channels)
        self.from_latent = sp.SparseLinear(latent_channels, model_channels[0])
        
        self.blocks = nn.ModuleList([])
        for i in range(len(num_blocks)):
            self.blocks.append(nn.ModuleList([]))
            for j in range(num_blocks[i]):
                self.blocks[-1].append(
                    globals()[block_type[i]](
                        model_channels[i],
                        **block_args[i],
                    )
                )
            if i < len(num_blocks) - 1:
                self.blocks[-1].append(
                    globals()[up_block_type[i]](
                        model_channels[i],
                        model_channels[i+1],
                        pred_subdiv=pred_subdiv,
                        **block_args[i],
                    )
                )
                    
        self.initialize_weights()
        if use_fp16:
            self.convert_to_fp16()
            
    @property
    def device(self) -> torch.device:
        """
        Return the device of the model.
        """
        return next(self.parameters()).device

    def convert_to_fp16(self) -> None:
        """
        Convert the torso of the model to float16.
        """
        self.blocks.apply(convert_module_to_f16)

    def convert_to_fp32(self) -> None:
        """
        Convert the torso of the model to float32.
        """
        self.blocks.apply(convert_module_to_f32)

    def initialize_weights(self) -> None:
        # Initialize transformer layers:
        def _basic_init(module):
            if isinstance(module, nn.Linear):
                torch.nn.init.xavier_uniform_(module.weight)
                if module.bias is not None:
                    nn.init.constant_(module.bias, 0)
        self.apply(_basic_init)

    def forward(self, x: sp.SparseTensor, guide_subs: Optional[List[sp.SparseTensor]] = None, return_subs: bool = False) -> sp.SparseTensor:
        assert guide_subs is None or self.pred_subdiv == False, "Only decoders with pred_subdiv=False can be used with guide_subs"
        assert return_subs == False or self.pred_subdiv == True, "Only decoders with pred_subdiv=True can be used with return_subs"
        
        h = self.from_latent(x)
        h = h.type(self.dtype)
        subs_gt = []
        subs = []
        for i, res in enumerate(self.blocks):
            for j, block in enumerate(res):
                if i < len(self.blocks) - 1 and j == len(res) - 1:
                    if self.pred_subdiv:
                        if self.training:
                            subs_gt.append(h.get_spatial_cache('subdivision'))
                        h, sub = block(h)
                        subs.append(sub)
                    else:
                        h = block(h, subdiv=guide_subs[i] if guide_subs is not None else None)
                else:
                    h = block(h)
        h = h.type(x.dtype)
        h = h.replace(F.layer_norm(h.feats, h.feats.shape[-1:]))
        h = self.output_layer(h)
        if self.training and self.pred_subdiv:
            return h, subs_gt, subs
        else:
            if return_subs:
                return h, subs
            else:
                return h
    
    def upsample(self, x: sp.SparseTensor, upsample_times: int) -> torch.Tensor:
        assert self.pred_subdiv == True, "Only decoders with pred_subdiv=True can be used with upsampling"
        
        h = self.from_latent(x)
        h = h.type(self.dtype)
        for i, res in enumerate(self.blocks):
            if i == upsample_times:
                return h.coords
            for j, block in enumerate(res):
                if i < len(self.blocks) - 1 and j == len(res) - 1:
                    h, sub = block(h)
                else:
                    h = block(h)