import os
import importlib
import numpy as np
from inspect import isfunction

import torch


def shape_to_str(x):
    shape_str = "x".join([str(x) for x in x.shape])
    return shape_str


def str2bool(v):
    if isinstance(v, bool):
        return v
    if v.lower() in ('yes', 'true', 't', 'y', '1'):
        return True
    elif v.lower() in ('no', 'false', 'f', 'n', '0'):
        return False
    else:
        raise ValueError('Boolean value expected.')


def get_obj_from_str(string, reload=False):
    module, cls = string.rsplit(".", 1)

    if reload:
        module_imp = importlib.import_module(module)
        importlib.reload(module_imp)
    return getattr(importlib.import_module(module, package=None), cls)


def instantiate_from_config(config):
    if not "target" in config:
        if config == '__is_first_stage__':
            return None
        elif config == "__is_unconditional__":
            return None
        raise KeyError("Expected key `target` to instantiate.")

    return get_obj_from_str(config["target"])(**config.get("params", dict()))


def shift_dim(x, src_dim=-1, dest_dim=-1, make_contiguous=True):
    """ Shifts src_tf dim to dest dim
        i.e. shift_dim(x, 1, -1) would be (b, c, t, h, w) -> (b, t, h, w, c)
    """
    n_dims = len(x.shape)
    if src_dim < 0:
        src_dim = n_dims + src_dim
    if dest_dim < 0:
        dest_dim = n_dims + dest_dim

    assert 0 <= src_dim < n_dims and 0 <= dest_dim < n_dims

    dims = list(range(n_dims))
    del dims[src_dim]

    permutation = []
    ctr = 0
    for i in range(n_dims):
        if i == dest_dim:
            permutation.append(src_dim)
        else:
            permutation.append(dims[ctr])
            ctr += 1
    x = x.permute(permutation)
    if make_contiguous:
        x = x.contiguous()
    return x


def torch_to_np(x):
    sample = x.detach().cpu()
    sample = ((sample + 1) * 127.5).clamp(0, 255).to(torch.uint8)
    if sample.dim() == 5:
        sample = sample.permute(0, 2, 3, 4, 1)
    else:
        sample = sample.permute(0, 2, 3, 1)
    sample = sample.contiguous().numpy()
    return sample


def np_to_torch_video(x):
    x = torch.tensor(x).permute(3, 0, 1, 2).float() # [t,h,w,c] -> [c,t,h,w]
    x = (x / 255 - 0.5) * 2
    return x


def load_npz_from_dir(data_dir):
    data = [np.load(os.path.join(data_dir, data_name))['arr_0'] for data_name in os.listdir(data_dir)]
    data = np.concatenate(data, axis=0)
    return data


def load_npz_from_paths(data_paths):
    data = [np.load(data_path)['arr_0'] for data_path in data_paths]
    data = np.concatenate(data, axis=0)
    return data


def ismap(x):
    if not isinstance(x, torch.Tensor):
        return False
    return (len(x.shape) == 4) and (x.shape[1] > 3)


def isimage(x):
    if not isinstance(x,torch.Tensor):
        return False
    return (len(x.shape) == 4) and (x.shape[1] == 3 or x.shape[1] == 1)


def exists(x):
    return x is not None


def default(val, d):
    if exists(val):
        return val
    return d() if isfunction(d) else d


def mean_flat(tensor):
    """
    https://github.com/openai/guided-diffusion/blob/27c20a8fab9cb472df5d6bdd6c8d11c8f430b924/guided_diffusion/nn.py#L86
    Take the mean over all non-batch dimensions.
    """
    return tensor.mean(dim=list(range(1, len(tensor.shape))))


def count_params(model, verbose=False):
    total_params = sum(p.numel() for p in model.parameters())
    if verbose:
        print(f"{model.__class__.__name__} has {total_params*1.e-6:.2f} M params.")
    return total_params


def check_istarget(name, para_list):
    """ 
    name: full name of source para
    para_list: partial name of target para 
    """
    istarget=False
    for para in para_list:
        if para in name:
            return True
    return istarget