"""
Util functions based on prompt-to-prompt.
"""

import os
import torch
import torch.nn.functional as F
import numpy as np
import  abc
from einops import rearrange
from typing import Optional, Union, Tuple, List, Callable, Dict


from torchvision.utils import save_image


class EmptyControl:
    
    
    def step_callback(self, x_t):
        return x_t
    
    def between_steps(self):
        return
    
    def __call__(self, attn, is_cross: bool, place_in_unet: str):
        return attn

    
class AttentionControl(abc.ABC):
    
    def step_callback(self, x_t):
        return x_t
    
    def between_steps(self):
        return
    
    @property
    def num_uncond_att_layers(self):
        return self.num_att_layers if self.LOW_RESOURCE else 0
    
    @abc.abstractmethod
    def forward (self, attn, is_cross: bool, place_in_unet: str):
        raise NotImplementedError

    def __call__(self, attn, is_cross: bool, place_in_unet: str):
        if self.cur_att_layer >= self.num_uncond_att_layers:
            h = attn.shape[0]
            attn[h // 2:] = self.forward(attn[h // 2:], is_cross, place_in_unet)
        self.cur_att_layer += 1
        if self.cur_att_layer == self.num_att_layers + self.num_uncond_att_layers:
            self.cur_att_layer = 0
            self.cur_step += 1
            # self.between_steps()
        return attn
    
    def reset(self):
        self.cur_step = 0
        self.cur_att_layer = 0

    def __init__(self):
        self.cur_step = 0
        self.num_att_layers = -1
        self.cur_att_layer = 0
        self.LOW_RESOURCE = False

        

class AttentionStore(AttentionControl):

    @staticmethod
    def get_empty_store():
        return {"down_cross": [], "mid_cross": [], "up_cross": [],
                "down_self": [],  "mid_self": [],  "up_self": []}

    def forward(self, attn, is_cross: bool, place_in_unet: str):
        key = f"{place_in_unet}_{'cross' if is_cross else 'self'}"
        # if attn.shape[1] <= 16 ** 2:  # avoid memory overhead
        #     self.step_store[key].append(attn)
        return attn

    def between_steps(self):
        if len(self.attention_store) == 0:
            self.attention_store = self.step_store
        else:
            for key in self.attention_store:
                for i in range(len(self.attention_store[key])):

                    self.attention_store[key][i] += self.step_store[key][i]
        self.step_store = self.get_empty_store()

    def get_average_attention(self):
        average_attention = {key: [item / self.cur_step for item in self.attention_store[key]] for key in self.attention_store}
        return average_attention


    def reset(self):
        super(AttentionStore, self).reset()
        self.step_store = self.get_empty_store()
        self.attention_store = {}

    def __init__(self):
        super(AttentionStore, self).__init__()
        self.step_store = self.get_empty_store()
        self.attention_store = {}

        
       
class SelfAttentionControlEdit(AttentionStore, abc.ABC):
    
    def step_callback(self, x_t):
        return x_t
        
    def replace_self_attention(self, attn_base, att_replace, place_in_unet):
        if att_replace.shape[2] <= 32 ** 2:
            attn_base = attn_base.unsqueeze(0).expand(att_replace.shape[0], *attn_base.shape)
            return attn_base
        else:
            return att_replace
    
    
    def forward(self, attn, is_cross: bool, place_in_unet: str):
        super(SelfAttentionControlEdit, self).forward(attn, is_cross, place_in_unet)
        if is_cross or (self.num_self_replace[0] <= self.cur_step < self.num_self_replace[1]):
            h = attn.shape[0] // (self.batch_size)
            attn = attn.reshape(self.batch_size, h, *attn.shape[1:])
            attn_base, attn_repalce = attn[0], attn[1:]
            if is_cross:
                pass
            else:
                attn[1:] = self.replace_self_attention(attn_base, attn_repalce, place_in_unet)
            attn = attn.reshape(self.batch_size * h, *attn.shape[2:])
        return attn
    
    def __init__(self, prompts, num_steps: int,
                 self_replace_steps: Union[float, Tuple[float, float]]):
        super(SelfAttentionControlEdit, self).__init__()
        self.batch_size = len(prompts)
        if type(self_replace_steps) is float:
            self_replace_steps = 0, self_replace_steps
        self.num_self_replace = int(num_steps * self_replace_steps[0]), int(num_steps * self_replace_steps[1])