from transformers import PreTrainedModel
from timm.models.resnet import BasicBlock, Bottleneck, ResNet
from resnet_model.configuration_resnet import ResnetConfig
import torch
import timm

BLOCK_MAPPING = {"basic": BasicBlock, "bottleneck": Bottleneck}


class ResnetModel(PreTrainedModel):  # 继承基类
    config_class = ResnetConfig

    def __init__(self, config):
        super().__init__(config)
        block_layer = BLOCK_MAPPING[config.block_type]
        self.model = ResNet(
            block_layer,
            config.layers,
            num_classes=config.num_classes,
            in_chans=config.input_channels,
            cardinality=config.cardinality,
            base_width=config.base_width,
            stem_width=config.stem_width,
            stem_type=config.stem_type,
            avg_down=config.avg_down,
        )

    def forward(self, tensor):
        return self.model.forward_features(tensor)


class ResnetModelForImageClassification(PreTrainedModel):  # 继承基类
    config_class = ResnetConfig

    def __init__(self, config):
        super().__init__(config)
        block_layer = BLOCK_MAPPING[config.block_type]
        self.model = ResNet(
            block_layer,
            config.layers,
            num_classes=config.num_classes,
            in_chans=config.input_channels,
            cardinality=config.cardinality,
            base_width=config.base_width,
            stem_width=config.stem_width,
            stem_type=config.stem_type,
            avg_down=config.avg_down,
        )

    def forward(self, tensor, labels=None):  # 前向方法
        logits = self.model(tensor)
        if labels is not None:
            loss = torch.nn.functional.cross_entropy(logits, labels)
            return {"loss": loss, "logits": logits}
        return {"logits": logits}


from transformers import AutoConfig, AutoModel, AutoModelForImageClassification


# resnet50d_config = ResnetConfig.from_pretrained("../custom-resnet")
# resnet50d = ResnetModelForImageClassification(resnet50d_config)
# pretrained_model = timm.create_model("resnet50d", pretrained=True)
# resnet50d.model.load_state_dict(pretrained_model.state_dict())



AutoConfig.register("resnet-t", ResnetConfig)  # 注册配置
AutoModel.register(ResnetConfig, ResnetModel)  # 注册普适模型
AutoModelForImageClassification.register(ResnetConfig, ResnetModelForImageClassification)  # 注册图像分类模型