import torch.nn as nn
from torch.nn.utils import fuse_conv_bn_eval


def fuse_all_conv_bn(model):
    stack = []
    for name, module in model.named_children():
        if list(module.named_children()):
            fuse_all_conv_bn(module)
            
        if isinstance(module, nn.BatchNorm2d):
            if not stack:
                continue
            if isinstance(stack[-1][1], nn.Conv2d):
                setattr(model, stack[-1][0], fuse_conv_bn_eval(stack[-1][1], module))
                setattr(model, name, nn.Identity())
        else:
            stack.append((name, module))
    return model


def load_state_dict_mute(self, state_dict: 'OrderedDict[str, Tensor]',
                        strict: bool = True):
        r"""Copies parameters and buffers from :attr:`state_dict` into
        this module and its descendants. If :attr:`strict` is ``True``, then
        the keys of :attr:`state_dict` must exactly match the keys returned
        by this module's :meth:`~torch.nn.Module.state_dict` function.

        Args:
            state_dict (dict): a dict containing parameters and
                persistent buffers.
            strict (bool, optional): whether to strictly enforce that the keys
                in :attr:`state_dict` match the keys returned by this module's
                :meth:`~torch.nn.Module.state_dict` function. Default: ``True``

        Returns:
            ``NamedTuple`` with ``missing_keys`` and ``unexpected_keys`` fields:
                * **missing_keys** is a list of str containing the missing keys
                * **unexpected_keys** is a list of str containing the unexpected keys
        """
        missing_keys: List[str] = []
        unexpected_keys: List[str] = []
        error_msgs: List[str] = []

        # copy state_dict so _load_from_state_dict can modify it
        metadata = getattr(state_dict, '_metadata', None)
        state_dict = state_dict.copy()
        if metadata is not None:
            # mypy isn't aware that "_metadata" exists in state_dict
            state_dict._metadata = metadata  # type: ignore[attr-defined]

        def load(module, prefix=''):
            local_metadata = {} if metadata is None else metadata.get(prefix[:-1], {})
            module._load_from_state_dict(
                state_dict, prefix, local_metadata, True, missing_keys, unexpected_keys, error_msgs)
            for name, child in module._modules.items():
                if child is not None:
                    load(child, prefix + name + '.')

        load(self)
        del load

        if strict:
            if len(unexpected_keys) > 0:
                error_msgs.insert(
                    0, 'Unexpected key(s) in state_dict: {}. '.format(
                        ', '.join('"{}"'.format(k) for k in unexpected_keys)))
            if len(missing_keys) > 0:
                error_msgs.insert(
                    0, 'Missing key(s) in state_dict: {}. '.format(
                        ', '.join('"{}"'.format(k) for k in missing_keys)))

