##################################################
# Copyright (c) Xuanyi Dong [GitHub D-X-Y], 2019 #
##################################################
import os, sys, torch
import os.path as osp
import numpy as np
import torchvision.datasets as dset
import torch.backends.cudnn as cudnn
import torchvision.transforms as transforms
from PIL import Image
from .DownsampledImageNet import ImageNet16


Dataset2Class = {'cifar10' : 10,
                 'cifar100': 100,
                 'imagenet-1k-s':1000,
                 'imagenet-1k' : 1000,
                 'ImageNet16'  : 1000,
                 'ImageNet16-150': 150,
                 'ImageNet16-120': 120,
                 'ImageNet16-200': 200}


class CUTOUT(object):

  def __init__(self, length):
    self.length = length

  def __repr__(self):
    return ('{name}(length={length})'.format(name=self.__class__.__name__, **self.__dict__))

  def __call__(self, img):
    h, w = img.size(1), img.size(2)
    mask = np.ones((h, w), np.float32)
    y = np.random.randint(h)
    x = np.random.randint(w)

    y1 = np.clip(y - self.length // 2, 0, h)
    y2 = np.clip(y + self.length // 2, 0, h)
    x1 = np.clip(x - self.length // 2, 0, w)
    x2 = np.clip(x + self.length // 2, 0, w)

    mask[y1: y2, x1: x2] = 0.
    mask = torch.from_numpy(mask)
    mask = mask.expand_as(img)
    img *= mask
    return img


imagenet_pca = {
    'eigval': np.asarray([0.2175, 0.0188, 0.0045]),
    'eigvec': np.asarray([
        [-0.5675, 0.7192, 0.4009],
        [-0.5808, -0.0045, -0.8140],
        [-0.5836, -0.6948, 0.4203],
    ])
}


class Lighting(object):
  def __init__(self, alphastd,
         eigval=imagenet_pca['eigval'],
         eigvec=imagenet_pca['eigvec']):
    self.alphastd = alphastd
    assert eigval.shape == (3,)
    assert eigvec.shape == (3, 3)
    self.eigval = eigval
    self.eigvec = eigvec

  def __call__(self, img):
    if self.alphastd == 0.:
      return img
    rnd = np.random.randn(3) * self.alphastd
    rnd = rnd.astype('float32')
    v = rnd
    old_dtype = np.asarray(img).dtype
    v = v * self.eigval
    v = v.reshape((3, 1))
    inc = np.dot(self.eigvec, v).reshape((3,))
    img = np.add(img, inc)
    if old_dtype == np.uint8:
      img = np.clip(img, 0, 255)
    img = Image.fromarray(img.astype(old_dtype), 'RGB')
    return img

  def __repr__(self):
    return self.__class__.__name__ + '()'


def get_datasets(name, root, cutout):

  if name == 'cifar10':
    mean = [x / 255 for x in [125.3, 123.0, 113.9]]
    std  = [x / 255 for x in [63.0, 62.1, 66.7]]
  elif name == 'cifar100':
    mean = [x / 255 for x in [129.3, 124.1, 112.4]]
    std  = [x / 255 for x in [68.2, 65.4, 70.4]]
  elif name.startswith('imagenet-1k'):
    mean, std = [0.485, 0.456, 0.406], [0.229, 0.224, 0.225]
  elif name.startswith('ImageNet16'):
    mean = [x / 255 for x in [122.68, 116.66, 104.01]]
    std  = [x / 255 for x in [63.22,  61.26 , 65.09]]
  else:
    raise TypeError("Unknow dataset : {:}".format(name))

  # Data Argumentation
  if name == 'cifar10' or name == 'cifar100':
    lists = [transforms.RandomHorizontalFlip(), transforms.RandomCrop(32, padding=4), transforms.ToTensor(), transforms.Normalize(mean, std)]
    if cutout > 0 : lists += [CUTOUT(cutout)]
    train_transform = transforms.Compose(lists)
    test_transform  = transforms.Compose([transforms.ToTensor(), transforms.Normalize(mean, std)])
    xshape = (1, 3, 32, 32)
  elif name.startswith('ImageNet16'):
    lists = [transforms.RandomHorizontalFlip(), transforms.RandomCrop(16, padding=2), transforms.ToTensor(), transforms.Normalize(mean, std)]
    if cutout > 0 : lists += [CUTOUT(cutout)]
    train_transform = transforms.Compose(lists)
    test_transform  = transforms.Compose([transforms.ToTensor(), transforms.Normalize(mean, std)])
    xshape = (1, 3, 16, 16)
  elif name == 'tiered':
    lists = [transforms.RandomHorizontalFlip(), transforms.RandomCrop(80, padding=4), transforms.ToTensor(), transforms.Normalize(mean, std)]
    if cutout > 0 : lists += [CUTOUT(cutout)]
    train_transform = transforms.Compose(lists)
    test_transform  = transforms.Compose([transforms.CenterCrop(80), transforms.ToTensor(), transforms.Normalize(mean, std)])
    xshape = (1, 3, 32, 32)
  elif name.startswith('imagenet-1k'):
    normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])
    if name == 'imagenet-1k':
      xlists    = [transforms.RandomResizedCrop(224)]
      xlists.append(
        transforms.ColorJitter(
        brightness=0.4,
        contrast=0.4,
        saturation=0.4,
        hue=0.2))
      xlists.append( Lighting(0.1))
    elif name == 'imagenet-1k-s':
      xlists    = [transforms.RandomResizedCrop(224, scale=(0.2, 1.0))]
    else: raise ValueError('invalid name : {:}'.format(name))
    xlists.append( transforms.RandomHorizontalFlip(p=0.5) )
    xlists.append( transforms.ToTensor() )
    xlists.append( normalize )
    train_transform = transforms.Compose(xlists)
    test_transform  = transforms.Compose([transforms.Resize(256), transforms.CenterCrop(224), transforms.ToTensor(), normalize])
    xshape = (1, 3, 224, 224)
  else:
    raise TypeError("Unknow dataset : {:}".format(name))

  if name == 'cifar10':
    train_data = dset.CIFAR10 (root, train=True , transform=train_transform, download=True)
    test_data  = dset.CIFAR10 (root, train=False, transform=test_transform , download=True)
    assert len(train_data) == 50000 and len(test_data) == 10000
  elif name == 'cifar100':
    train_data = dset.CIFAR100(root, train=True , transform=train_transform, download=True)
    test_data  = dset.CIFAR100(root, train=False, transform=test_transform , download=True)
    assert len(train_data) == 50000 and len(test_data) == 10000
  elif name.startswith('imagenet-1k'):
    train_data = dset.ImageFolder(osp.join(root, 'train'), train_transform)
    test_data  = dset.ImageFolder(osp.join(root, 'val'),   test_transform)
    assert len(train_data) == 1281167 and len(test_data) == 50000, 'invalid number of images : {:} & {:} vs {:} & {:}'.format(len(train_data), len(test_data), 1281167, 50000)
  elif name == 'ImageNet16':
    train_data = ImageNet16(root, True , train_transform)
    test_data  = ImageNet16(root, False, test_transform)
    assert len(train_data) == 1281167 and len(test_data) == 50000
  elif name == 'ImageNet16-120':
    train_data = ImageNet16(root, True , train_transform, 120)
    test_data  = ImageNet16(root, False, test_transform , 120)
    assert len(train_data) == 151700 and len(test_data) == 6000
  elif name == 'ImageNet16-150':
    train_data = ImageNet16(root, True , train_transform, 150)
    test_data  = ImageNet16(root, False, test_transform , 150)
    assert len(train_data) == 190272 and len(test_data) == 7500
  elif name == 'ImageNet16-200':
    train_data = ImageNet16(root, True , train_transform, 200)
    test_data  = ImageNet16(root, False, test_transform , 200)
    assert len(train_data) == 254775 and len(test_data) == 10000
  else: raise TypeError("Unknow dataset : {:}".format(name))
  
  class_num = Dataset2Class[name]
  return train_data, test_data, xshape, class_num

#if __name__ == '__main__':
#  train_data, test_data, xshape, class_num = dataset = get_datasets('cifar10', '/data02/dongxuanyi/.torch/cifar.python/', -1)
#  import pdb; pdb.set_trace()
