import copy
import pickle

import numpy as np
import torch
import torch.utils.data as data
from PIL import Image
from torchvision import transforms
from torchvision.datasets import DatasetFolder
from torchvision.datasets import MNIST, EMNIST, CIFAR10

IMG_EXTENSIONS = ('.jpg', '.jpeg', '.png', '.ppm', '.bmp', '.pgm', '.tif', '.tiff', '.webp')


def accimage_loader(path):
    import accimage
    try:
        return accimage.Image(path)
    except IOError:
        # Potentially a decoding problem, fall back to PIL.Image
        return pil_loader(path)


def pil_loader(path):
    # open path as file to avoid ResourceWarning (https://github.com/python-pillow/Pillow/issues/835)
    with open(path, 'rb') as f:
        img = Image.open(f)
        return img.convert('RGB')


def default_loader(path):
    from torchvision import get_image_backend
    if get_image_backend() == 'accimage':
        return accimage_loader(path)
    else:
        return pil_loader(path)


class MNIST_truncated(data.Dataset):

    def __init__(self, root, dataidxs=None, train=True, transform=None, target_transform=None, download=False):

        self.root = root
        self.dataidxs = dataidxs
        self.train = train
        self.transform = transform
        self.target_transform = target_transform
        self.download = download

        self.data, self.target = self.__build_truncated_dataset__()

    def __build_truncated_dataset__(self):

        mnist_dataobj = MNIST(self.root, self.train, self.transform, self.target_transform, self.download)

        if self.train:
            data = mnist_dataobj.train_data
            target = mnist_dataobj.train_labels
        else:
            data = mnist_dataobj.test_data
            target = mnist_dataobj.test_labels

        if self.dataidxs is not None:
            data = data[self.dataidxs]
            target = target[self.dataidxs]

        return data, target

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (image, target) where target is index of the target class.
        """
        img, target = self.data[index], self.target[index]

        # doing this so that it is consistent with all other datasets
        # to return a PIL Image
        img = Image.fromarray(img.numpy(), mode='L')

        if self.transform is not None:
            img = self.transform(img)

        if self.target_transform is not None:
            target = self.target_transform(target)

        return img, target

    def __len__(self):
        return len(self.data)


class EMNIST_truncated(data.Dataset):

    def __init__(self, root, dataidxs=None, train=True, transform=None, target_transform=None, download=False):

        self.root = root
        self.dataidxs = dataidxs
        self.train = train
        self.transform = transform
        self.target_transform = target_transform
        self.download = download

        self.data, self.target = self.__build_truncated_dataset__()

    def __build_truncated_dataset__(self):
        emnist_dataobj = EMNIST(self.root, split="digits", train=self.train,
                                transform=self.transform,
                                target_transform=self.target_transform,
                                download=self.download)

        if self.train:
            data = emnist_dataobj.train_data
            target = emnist_dataobj.train_labels
        else:
            data = emnist_dataobj.test_data
            target = emnist_dataobj.test_labels

        if self.dataidxs is not None:
            data = data[self.dataidxs]
            target = target[self.dataidxs]

        return data, target

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (image, target) where target is index of the target class.
        """
        img, target = self.data[index], self.target[index]

        # doing this so that it is consistent with all other datasets
        # to return a PIL Image
        img = Image.fromarray(img.numpy(), mode='L')

        if self.transform is not None:
            img = self.transform(img)

        if self.target_transform is not None:
            target = self.target_transform(target)

        return img, target

    def __len__(self):
        return len(self.data)


def get_ardis_dataset():
    # load the data from csv's
    ardis_images = np.loadtxt('./../../../data/edge_case_examples/ARDIS/ARDIS_train_2828.csv', dtype='float')
    ardis_labels = np.loadtxt('./../../../data/edge_case_examples/ARDIS/ARDIS_train_labels.csv', dtype='float')

    #### reshape to be [samples][width][height]
    ardis_images = ardis_images.reshape(ardis_images.shape[0], 28, 28).astype('float32')

    # labels are one-hot encoded
    indices_seven = np.where(ardis_labels[:, 7] == 1)[0]
    images_seven = ardis_images[indices_seven, :]
    images_seven = torch.tensor(images_seven).type(torch.uint8)

    labels_seven = torch.tensor([7 for y in ardis_labels])

    ardis_dataset = EMNIST('./../../../data', split="digits", train=True, download=True,
                           transform=transforms.Compose([
                               transforms.ToTensor(),
                               transforms.Normalize((0.1307,), (0.3081,))
                           ]))

    ardis_dataset.data = images_seven
    ardis_dataset.targets = labels_seven

    return ardis_dataset


def get_southwest_dataset(attack_case='normal-case'):
    if attack_case == 'normal-case':
        with open('./../../../data/edge_case_examples/southwest_cifar10/southwest_images_honest_full_normal.pkl',
                  'rb') as train_f:
            saved_southwest_dataset_train = pickle.load(train_f)
    elif attack_case == 'almost-edge-case':
        with open('./../../../data/edge_case_examples/southwest_cifar10/southwest_images_honest_almost_edge_case.pkl',
                  'rb') as train_f:
            saved_southwest_dataset_train = pickle.load(train_f)
    else:
        saved_southwest_dataset_train = None
    return saved_southwest_dataset_train


class EMNIST_NormalCase_truncated(data.Dataset):
    '''
    we use this class for normal case attack where normal 
    users also hold the poisoned data point with true label 
    '''

    def __init__(self, root,
                 dataidxs=None,
                 train=True,
                 transform=None,
                 target_transform=None,
                 download=False,
                 user_id=0,
                 num_total_users=3383,
                 poison_type="ardis",
                 ardis_dataset_train=None,
                 attack_case='normal-case'):

        self.root = root
        self.dataidxs = dataidxs
        self.train = train
        self.transform = transform
        self.target_transform = target_transform
        self.download = download

        if attack_case == 'normal-case':
            self._num_users_hold_edge_data = int(
                3383 / 20)  # we allow 1/20 of the users (other than the attacker) to hold the edge data.
        else:
            # almost edge case
            self._num_users_hold_edge_data = 66  # ~2% of users hold data

        if poison_type == "ardis":
            self.ardis_dataset_train = ardis_dataset_train
            partition = np.array_split(np.arange(self.ardis_dataset_train.data.shape[0]),
                                       int(self._num_users_hold_edge_data))

            if user_id in np.arange(self._num_users_hold_edge_data):
                user_partition = partition[user_id]
                self.saved_ardis_dataset_train = self.ardis_dataset_train.data[user_partition]
                self.saved_ardis_label_train = self.ardis_dataset_train.targets[user_partition]
            else:
                user_partition = []
                self.saved_ardis_dataset_train = self.ardis_dataset_train.data[user_partition]
                self.saved_ardis_label_train = self.ardis_dataset_train.targets[user_partition]
        else:
            NotImplementedError("Unsupported poison type for normal case attack ...")

        # logging.info("USER: {} got {} points".format(user_id, len(self.saved_ardis_dataset_train.data)))
        self.data, self.target = self.__build_truncated_dataset__()

        # if self.dataidxs is not None:
        #    print("$$$$$$$$ Inside data loader: user ID: {}, Combined data: {}, Ori data shape: {}".format(
        #                user_id, self.data.shape, len(dataidxs)))

    def __build_truncated_dataset__(self):

        emnist_dataobj = EMNIST(self.root, split="digits", train=self.train,
                                transform=self.transform,
                                target_transform=self.target_transform,
                                download=self.download)

        if self.train:
            data = emnist_dataobj.data
            target = np.array(emnist_dataobj.targets)
        else:
            data = emnist_dataobj.data
            target = np.array(emnist_dataobj.targets)

        if self.dataidxs is not None:
            data = data[self.dataidxs]
            target = target[self.dataidxs]

        data = np.append(data, self.saved_ardis_dataset_train, axis=0)
        target = np.append(target, self.saved_ardis_label_train, axis=0)
        return data, target

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (image, target) where target is index of the target class.
        """
        img, target = self.data[index], self.target[index]

        if self.transform is not None:
            img = self.transform(img)

        if self.target_transform is not None:
            target = self.target_transform(target)

        return img, target

    def __len__(self):
        return len(self.data)


class CIFAR10_truncated(data.Dataset):

    def __init__(self, root, dataidxs=None, train=True, transform=None, target_transform=None, download=False):

        self.root = root
        self.dataidxs = dataidxs
        self.train = train
        self.transform = transform
        self.target_transform = target_transform
        self.download = download

        self.data, self.target = self.__build_truncated_dataset__()

    def __build_truncated_dataset__(self):

        cifar_dataobj = CIFAR10(self.root, self.train, self.transform, self.target_transform, self.download)

        if self.train:
            # print("train member of the class: {}".format(self.train))
            # data = cifar_dataobj.train_data
            data = cifar_dataobj.data
            target = np.array(cifar_dataobj.targets)
        else:
            data = cifar_dataobj.data
            target = np.array(cifar_dataobj.targets)

        if self.dataidxs is not None:
            data = data[self.dataidxs]
            target = target[self.dataidxs]

        return data, target

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (image, target) where target is index of the target class.
        """
        img, target = self.data[index], self.target[index]

        if self.transform is not None:
            img = self.transform(img)

        if self.target_transform is not None:
            target = self.target_transform(target)

        return img, target

    def __len__(self):
        return len(self.data)


class CIFAR10NormalCase_truncated(data.Dataset):
    '''
    we use this class for normal case attack where normal 
    users also hold the poisoned data point with true label 
    '''

    def __init__(self, root,
                 dataidxs=None,
                 train=True,
                 transform=None,
                 target_transform=None,
                 download=False,
                 user_id=0,
                 num_total_users=200,
                 poison_type="southwest",
                 ardis_dataset_train=None,
                 attack_case="normal-case"):

        self.root = root
        self.dataidxs = dataidxs
        self.train = train
        self.transform = transform
        self.target_transform = target_transform
        self.download = download

        self._DA_ratio = 4  # we hard code this argument for now
        if attack_case == "normal-case":
            self._num_users_hold_edge_data = 10  # we allow 5% of the users (other than the attacker) to hold the edge data.
        elif attack_case == "almost-edge-case":
            self._num_users_hold_edge_data = 5  # we allow 2.5% of the users (other than the attacker) to hold the edge data.
        else:
            NotImplementedError("Unsupported attacking case ...")

        self.saved_southwest_dataset_train = copy.deepcopy(ardis_dataset_train)

        if poison_type == "southwest":
            partition = np.array_split(np.arange(int(self.saved_southwest_dataset_train.shape[0] / self._DA_ratio)),
                                       int(self._num_users_hold_edge_data))

            self.__aggregated_mapped_user_partition = []
            # the maped sampling thing will happen here:
            # we just generate `self.__aggregated_mapped_user_partition` once
            prev_user_counter = 0

            for bi_index, bi in enumerate(partition):
                mapped_user_partition = []
                for idx, up in enumerate(bi):
                    mapped_user_partition.extend(
                        [prev_user_counter + idx * self._DA_ratio + i for i in range(self._DA_ratio)])
                prev_user_counter += len(bi) * self._DA_ratio
                self.__aggregated_mapped_user_partition.append(mapped_user_partition)

            if user_id in np.arange(self._num_users_hold_edge_data):
                user_partition = self.__aggregated_mapped_user_partition[user_id]
                print("######### user_partition: {}, user id: {}".format(user_partition, user_id))

                self.saved_southwest_dataset_train = self.saved_southwest_dataset_train[user_partition, :, :, :]
                self.saved_southwest_label_train = 0 * np.ones((self.saved_southwest_dataset_train.shape[0],),
                                                               dtype=int)
            else:
                user_partition = []
                self.saved_southwest_dataset_train = self.saved_southwest_dataset_train[user_partition, :, :, :]
                self.saved_southwest_label_train = 0 * np.ones((self.saved_southwest_dataset_train.shape[0],),
                                                               dtype=int)
        else:
            NotImplementedError("Unsupported poison type for normal case attack ...")

        self.data, self.target = self.__build_truncated_dataset__()

        # if self.dataidxs is not None:
        #    print("$$$$$$$$ Inside data loader: user ID: {}, Combined data: {}, Ori data shape: {}".format(
        #                user_id, self.data.shape, len(dataidxs)))

    def __build_truncated_dataset__(self):

        cifar_dataobj = CIFAR10(self.root, self.train, self.transform, self.target_transform, self.download)

        if self.train:
            data = cifar_dataobj.data
            target = np.array(cifar_dataobj.targets)
        else:
            data = cifar_dataobj.data
            target = np.array(cifar_dataobj.targets)

        if self.dataidxs is not None:
            data = data[self.dataidxs]
            target = target[self.dataidxs]

        data = np.append(data, self.saved_southwest_dataset_train, axis=0)
        target = np.append(target, self.saved_southwest_label_train, axis=0)
        return data, target

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (image, target) where target is index of the target class.
        """
        img, target = self.data[index], self.target[index]

        if self.transform is not None:
            img = self.transform(img)

        if self.target_transform is not None:
            target = self.target_transform(target)

        return img, target

    def __len__(self):
        return len(self.data)


class CIFAR10_Poisoned(data.Dataset):
    """
    The main motivation for this object is to adopt different transform on the mixed poisoned dataset:
    e.g. there are `M` good examples and `N` poisoned examples in the poisoned dataset.

    """

    def __init__(self, root, clean_indices, poisoned_indices, dataidxs=None, train=True, transform_clean=None,
                 transform_poison=None, target_transform=None, download=False):

        self.root = root
        self.dataidxs = dataidxs
        self.train = train
        self.transform_clean = transform_clean
        self.transform_poison = transform_poison
        self.target_transform = target_transform
        self.download = download
        self._clean_indices = clean_indices
        self._poisoned_indices = poisoned_indices

        cifar_dataobj = CIFAR10(self.root, self.train, self.transform_clean, self.target_transform, self.download)

        self.data = cifar_dataobj.data
        self.target = np.array(cifar_dataobj.targets)

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (image, target) where target is index of the target class.
        """
        img, target = self.data[index], self.target[index]

        # we always assume that the transform function is not None
        if index in self._clean_indices:
            img = self.transform_clean(img)
        elif index in self._poisoned_indices:
            img = self.transform_poison(img)
        else:
            raise NotImplementedError("Indices should be in clean or poisoned!")

        # if index in self.transform is not None:
        #    img = self.transform(img)
        if self.target_transform is not None:
            target = self.target_transform(target)
        return img, target

    def __len__(self):
        return len(self.data)


class ImageFolderTruncated(DatasetFolder):
    """A generic data loader where the images are arranged in this way: ::

        root/dog/xxx.png
        root/dog/xxy.png
        root/dog/xxz.png

        root/cat/123.png
        root/cat/nsdf3.png
        root/cat/asd932_.png

    Args:
        root (string): Root directory path.
        transform (callable, optional): A function/transform that  takes in an PIL image
            and returns a transformed version. E.g, ``transforms.RandomCrop``
        target_transform (callable, optional): A function/transform that takes in the
            target and transforms it.
        loader (callable, optional): A function to load an image given its path.
        is_valid_file (callable, optional): A function that takes path of an Image file
            and check if the file is a valid_file (used to check of corrupt files)

     Attributes:
        classes (list): List of the class names.
        class_to_idx (dict): Dict with items (class_name, class_index).
        imgs (list): List of (image path, class_index) tuples
    """

    def __init__(self, root, dataidxs=None, transform=None, target_transform=None,
                 loader=default_loader, is_valid_file=None):
        super(ImageFolderTruncated, self).__init__(root, loader, IMG_EXTENSIONS if is_valid_file is None else None,
                                                   transform=transform,
                                                   target_transform=target_transform,
                                                   is_valid_file=is_valid_file)
        self.imgs = self.samples
        self.dataidxs = dataidxs

        ### we need to fetch training labels out here:
        self._train_labels = np.array([tup[-1] for tup in self.imgs])

        self.__build_truncated_dataset__()

    def __build_truncated_dataset__(self):
        if self.dataidxs is not None:
            # self.imgs = self.imgs[self.dataidxs]
            self.imgs = [self.imgs[idx] for idx in self.dataidxs]

    def __len__(self):
        return len(self.imgs)

    def __getitem__(self, index):
        """
        Args:
            index (int): Index

        Returns:
            tuple: (sample, target) where target is class_index of the target class.
        """
        path, target = self.imgs[index]
        sample = self.loader(path)
        if self.transform is not None:
            sample = self.transform(sample)
        if self.target_transform is not None:
            target = self.target_transform(target)
        return sample, target

    @property
    def get_train_labels(self):
        return self._train_labels
