import os

import torch
import torch.nn.functional as F

scaled_dot_product_attention = F.scaled_dot_product_attention
if os.environ.get('CA_USE_SAGEATTN', '0') == '1':
    try:
        from sageattention import sageattn
    except ImportError:
        raise ImportError('Please install the package "sageattention" to use this USE_SAGEATTN.')
    scaled_dot_product_attention = sageattn


class CrossAttentionProcessor:
    def __call__(self, attn, q, k, v):
        out = scaled_dot_product_attention(q, k, v)
        return out