from typing import Optional
import torch
from diffusers.utils import USE_PEFT_BACKEND
from diffusers.models.lora import LoRACompatibleConv, LoRACompatibleLinear
from diffusers.models.normalization import AdaGroupNorm
from diffusers.models.activations import get_activation
from diffusers.models.attention_processor import SpatialNorm
from diffusers.models.resnet import upsample_2d, downsample_2d, Downsample2D, Upsample2D
import torch.nn as nn
import torch.nn.functional as F
from functools import partial
from .SPADEGroupNorm import SPADEGroupNorm


class ResnetBlock2D(nn.Module):
    r"""
    A Resnet block.

    Parameters:
        in_channels (`int`): The number of channels in the input.
        out_channels (`int`, *optional*, default to be `None`):
            The number of output channels for the first conv2d layer. If None, same as `in_channels`.
        dropout (`float`, *optional*, defaults to `0.0`): The dropout probability to use.
        temb_channels (`int`, *optional*, default to `512`): the number of channels in timestep embedding.
        groups (`int`, *optional*, default to `32`): The number of groups to use for the first normalization layer.
        groups_out (`int`, *optional*, default to None):
            The number of groups to use for the second normalization layer. if set to None, same as `groups`.
        eps (`float`, *optional*, defaults to `1e-6`): The epsilon to use for the normalization.
        non_linearity (`str`, *optional*, default to `"swish"`): the activation function to use.
        time_embedding_norm (`str`, *optional*, default to `"default"` ): Time scale shift config.
            By default, apply timestep embedding conditioning with a simple shift mechanism. Choose "scale_shift" or
            "ada_group" for a stronger conditioning with scale and shift.
        kernel (`torch.FloatTensor`, optional, default to None): FIR filter, see
            [`~models.resnet.FirUpsample2D`] and [`~models.resnet.FirDownsample2D`].
        output_scale_factor (`float`, *optional*, default to be `1.0`): the scale factor to use for the output.
        use_in_shortcut (`bool`, *optional*, default to `True`):
            If `True`, add a 1x1 nn.conv2d layer for skip-connection.
        up (`bool`, *optional*, default to `False`): If `True`, add an upsample layer.
        down (`bool`, *optional*, default to `False`): If `True`, add a downsample layer.
        conv_shortcut_bias (`bool`, *optional*, default to `True`):  If `True`, adds a learnable bias to the
            `conv_shortcut` output.
        conv_2d_out_channels (`int`, *optional*, default to `None`): the number of channels in the output.
            If None, same as `out_channels`.
    """

    def __init__(
        self,
        *,
        in_channels: int,
        out_channels: Optional[int] = None,
        conv_shortcut: bool = False,
        dropout: float = 0.0,
        temb_channels: int = 512,
        groups: int = 32,
        groups_out: Optional[int] = None,
        pre_norm: bool = True,
        eps: float = 1e-6,
        non_linearity: str = "swish",
        skip_time_act: bool = False,
        time_embedding_norm: str = "default",  # default, scale_shift, ada_group, spatial
        kernel: Optional[torch.FloatTensor] = None,
        output_scale_factor: float = 1.0,
        use_in_shortcut: Optional[bool] = None,
        up: bool = False,
        down: bool = False,
        conv_shortcut_bias: bool = True,
        conv_2d_out_channels: Optional[int] = None,
        SPADE_chs = (320, 640, 1280, 1280),
        normalization_type = None,
        half_the_ch = False,
        is_crossAttn = None

    ):
        super().__init__()
        self.pre_norm = pre_norm
        self.pre_norm = True
        self.in_channels = in_channels
        out_channels = in_channels if out_channels is None else out_channels
        self.out_channels = out_channels
        self.use_conv_shortcut = conv_shortcut
        self.up = up
        self.down = down
        self.output_scale_factor = output_scale_factor
        self.time_embedding_norm = time_embedding_norm
        self.skip_time_act = skip_time_act
        self.normalization_type = normalization_type
        self.SPADE_chs = SPADE_chs
        self.is_crossAttn = is_crossAttn

        linear_cls = nn.Linear if USE_PEFT_BACKEND else LoRACompatibleLinear
        conv_cls = nn.Conv2d if USE_PEFT_BACKEND else LoRACompatibleConv

        if groups_out is None:
            groups_out = groups

        if self.time_embedding_norm == "ada_group":
            self.norm1 = AdaGroupNorm(temb_channels, in_channels, groups, eps=eps)
        elif self.time_embedding_norm == "spatial":
            self.norm1 = SpatialNorm(in_channels, temb_channels)
        elif self.normalization_type == "SPADE":
            self.norm1 = SPADEGroupNorm(in_channels=in_channels, out_channels=out_channels if not half_the_ch else int(out_channels / 2), n_hidden=out_channels, 
                                        groups=groups, eps=eps)
        else:
            self.norm1 = torch.nn.GroupNorm(num_groups=groups, num_channels=in_channels, eps=eps, affine=True)

        self.conv1 = conv_cls(in_channels, out_channels, kernel_size=3, stride=1, padding=1)

        if temb_channels is not None:
            if self.time_embedding_norm == "default":
                self.time_emb_proj = linear_cls(temb_channels, out_channels)
            elif self.time_embedding_norm == "scale_shift":
                self.time_emb_proj = linear_cls(temb_channels, 2 * out_channels)
            elif self.time_embedding_norm == "ada_group" or self.time_embedding_norm == "spatial":
                self.time_emb_proj = None
            else:
                raise ValueError(f"unknown time_embedding_norm : {self.time_embedding_norm} ")
        else:
            self.time_emb_proj = None

        if self.time_embedding_norm == "ada_group":
            self.norm2 = AdaGroupNorm(temb_channels, out_channels, groups_out, eps=eps)
        elif self.time_embedding_norm == "spatial":
            self.norm2 = SpatialNorm(out_channels, temb_channels)
        elif self.normalization_type == "SPADE":
            self.norm2 = SPADEGroupNorm(in_channels=out_channels, out_channels=out_channels, n_hidden=out_channels,
                                         groups=groups_out, eps=eps)
        else:
            self.norm2 = torch.nn.GroupNorm(num_groups=groups_out, num_channels=out_channels, eps=eps, affine=True)

        self.dropout = torch.nn.Dropout(dropout)
        conv_2d_out_channels = conv_2d_out_channels or out_channels
        self.conv2 = conv_cls(out_channels, conv_2d_out_channels, kernel_size=3, stride=1, padding=1)

        self.nonlinearity = get_activation(non_linearity)

        self.upsample = self.downsample = None
        if self.up:
            if kernel == "fir":
                fir_kernel = (1, 3, 3, 1)
                self.upsample = lambda x: upsample_2d(x, kernel=fir_kernel)
            elif kernel == "sde_vp":
                self.upsample = partial(F.interpolate, scale_factor=2.0, mode="nearest")
            else:
                self.upsample = Upsample2D(in_channels, use_conv=False)
        elif self.down:
            if kernel == "fir":
                fir_kernel = (1, 3, 3, 1)
                self.downsample = lambda x: downsample_2d(x, kernel=fir_kernel)
            elif kernel == "sde_vp":
                self.downsample = partial(F.avg_pool2d, kernel_size=2, stride=2)
            else:
                self.downsample = Downsample2D(in_channels, use_conv=False, padding=1, name="op")

        self.use_in_shortcut = self.in_channels != conv_2d_out_channels if use_in_shortcut is None else use_in_shortcut

        self.conv_shortcut = None
        if self.use_in_shortcut:
            self.conv_shortcut = conv_cls(
                in_channels, conv_2d_out_channels, kernel_size=1, stride=1, padding=0, bias=conv_shortcut_bias
            )

    def forward(self, input_tensor, temb, scale: float = 1.0,
                segmaps=None):
        hidden_states = input_tensor

        if self.time_embedding_norm == "ada_group" or self.time_embedding_norm == "spatial":
            hidden_states = self.norm1(hidden_states, temb)
        elif self.normalization_type == "SPADE" and segmaps != None:
            if self.is_crossAttn:
                i = self.SPADE_chs.index(hidden_states.size(1))
                segmap = segmaps[i]
                if segmap.shape != hidden_states.shape:
                    segmap = F.interpolate(segmap, size=hidden_states.size()[2:], mode='nearest')
            elif self.is_crossAttn != None and not self.is_crossAttn:
                segmap = segmaps[-1]

            hidden_states = self.norm1(hidden_states, segmap)

        else:
            hidden_states = self.norm1(hidden_states)

        hidden_states = self.nonlinearity(hidden_states)

        if self.upsample is not None:
            # upsample_nearest_nhwc fails with large batch sizes. see https://github.com/huggingface/diffusers/issues/984
            if hidden_states.shape[0] >= 64:
                input_tensor = input_tensor.contiguous()
                hidden_states = hidden_states.contiguous()
            input_tensor = (
                self.upsample(input_tensor, scale=scale)
                if isinstance(self.upsample, Upsample2D)
                else self.upsample(input_tensor)
            )
            hidden_states = (
                self.upsample(hidden_states, scale=scale)
                if isinstance(self.upsample, Upsample2D)
                else self.upsample(hidden_states)
            )
        elif self.downsample is not None:
            input_tensor = (
                self.downsample(input_tensor, scale=scale)
                if isinstance(self.downsample, Downsample2D)
                else self.downsample(input_tensor)
            )
            hidden_states = (
                self.downsample(hidden_states, scale=scale)
                if isinstance(self.downsample, Downsample2D)
                else self.downsample(hidden_states)
            )

        hidden_states = self.conv1(hidden_states, scale) if not USE_PEFT_BACKEND else self.conv1(hidden_states)

        if self.time_emb_proj is not None:
            if not self.skip_time_act:
                temb = self.nonlinearity(temb)
            temb = (
                self.time_emb_proj(temb, scale)[:, :, None, None]
                if not USE_PEFT_BACKEND
                else self.time_emb_proj(temb)[:, :, None, None]
            )

        if temb is not None and self.time_embedding_norm == "default":
            hidden_states = hidden_states + temb

        if self.time_embedding_norm == "ada_group" or self.time_embedding_norm == "spatial":
            hidden_states = self.norm2(hidden_states, temb)
        elif self.normalization_type == "SPADE" and segmaps != None:
            if self.is_crossAttn:
                i = self.SPADE_chs.index(hidden_states.size(1))
                segmap = segmaps[i]
            elif self.is_crossAttn != None and not self.is_crossAttn:
                segmap = segmaps[-1]
                
            hidden_states = self.norm2(hidden_states, segmap)
        else:
            hidden_states = self.norm2(hidden_states)

        if temb is not None and self.time_embedding_norm == "scale_shift":
            scale, shift = torch.chunk(temb, 2, dim=1)
            hidden_states = hidden_states * (1 + scale) + shift

        hidden_states = self.nonlinearity(hidden_states)

        hidden_states = self.dropout(hidden_states)
        hidden_states = self.conv2(hidden_states, scale) if not USE_PEFT_BACKEND else self.conv2(hidden_states)

        if self.conv_shortcut is not None:
            input_tensor = (
                self.conv_shortcut(input_tensor, scale) if not USE_PEFT_BACKEND else self.conv_shortcut(input_tensor)
            )

        output_tensor = (input_tensor + hidden_states) / self.output_scale_factor

        return output_tensor