# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the license found in the
# LICENSE file in the root directory of this source tree.


import torch.nn as nn
from transformers import ViTImageProcessor, ViTModel, AutoImageProcessor, AutoModel, Dinov2Model

class DinoWrapper(nn.Module):
    """
    Dino v1 wrapper using huggingface transformer implementation.
    """
    def __init__(self, model_name: str, freeze: bool = True):
        super().__init__()
        self.model, self.processor = self._build_dino(model_name)
        if freeze:
            self._freeze()

    def forward(self, image):
        # image: [N, C, H, W], on cpu
        # RGB image with [0,1] scale and properly sized
        inputs = self.processor(images=image.float(), return_tensors="pt", do_rescale=False, do_resize=False).to(self.model.device)
        # This resampling of positional embedding uses bicubic interpolation
        outputs = self.model(**inputs)
        last_hidden_states = outputs.last_hidden_state
        return last_hidden_states

    def _freeze(self):
        print(f"======== Freezing DinoWrapper ========")
        self.model.eval()
        for name, param in self.model.named_parameters():
            param.requires_grad = False

    @staticmethod
    def _build_dino(model_name: str, proxy_error_retries: int = 3, proxy_error_cooldown: int = 5):
        import requests
        try:
            processor = AutoImageProcessor.from_pretrained('facebook/dinov2-base')
            processor.do_center_crop = False
            model = AutoModel.from_pretrained('facebook/dinov2-base')
            return model, processor
        except requests.exceptions.ProxyError as err:
            if proxy_error_retries > 0:
                print(f"Huggingface ProxyError: Retrying in {proxy_error_cooldown} seconds...")
                import time
                time.sleep(proxy_error_cooldown)
                return DinoWrapper._build_dino(model_name, proxy_error_retries - 1, proxy_error_cooldown)
            else:
                raise err