import os
import re

import numpy as np
import pandas as pd
import requests
import torch
import torchvision
import torchvision.transforms as transforms
from PIL import Image
from torchvision.datasets.folder import IMG_EXTENSIONS, pil_loader
from torchvision.io import write_video
from torchvision.utils import save_image


VID_EXTENSIONS = (".mp4", ".avi", ".mov", ".mkv")

regex = re.compile(
    r"^(?:http|ftp)s?://"  # http:// or https://
    r"(?:(?:[A-Z0-9](?:[A-Z0-9-]{0,61}[A-Z0-9])?\.)+(?:[A-Z]{2,6}\.?|[A-Z0-9-]{2,}\.?)|"  # domain...
    r"localhost|"  # localhost...
    r"\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})"  # ...or ip
    r"(?::\d+)?"  # optional port
    r"(?:/?|[/?]\S+)$",
    re.IGNORECASE,
)

import numbers
import random

import numpy as np
import torch


def _is_tensor_video_clip(clip):
    if not torch.is_tensor(clip):
        raise TypeError("clip should be Tensor. Got %s" % type(clip))

    if not clip.ndimension() == 4:
        raise ValueError("clip should be 4D. Got %dD" % clip.dim())

    return True


def crop(clip, i, j, h, w):
    """
    Args:
        clip (torch.tensor): Video clip to be cropped. Size is (T, C, H, W)
    """
    if len(clip.size()) != 4:
        raise ValueError("clip should be a 4D tensor")
    return clip[..., i : i + h, j : j + w]


def resize(clip, target_size, interpolation_mode):
    if len(target_size) != 2:
        raise ValueError(f"target size should be tuple (height, width), instead got {target_size}")
    return torch.nn.functional.interpolate(clip, size=target_size, mode=interpolation_mode, align_corners=False)


def resize_scale(clip, target_size, interpolation_mode):
    if len(target_size) != 2:
        raise ValueError(f"target size should be tuple (height, width), instead got {target_size}")
    H, W = clip.size(-2), clip.size(-1)
    scale_ = target_size[0] / min(H, W)
    return torch.nn.functional.interpolate(clip, scale_factor=scale_, mode=interpolation_mode, align_corners=False)


def resized_crop(clip, i, j, h, w, size, interpolation_mode="bilinear"):
    """
    Do spatial cropping and resizing to the video clip
    Args:
        clip (torch.tensor): Video clip to be cropped. Size is (T, C, H, W)
        i (int): i in (i,j) i.e coordinates of the upper left corner.
        j (int): j in (i,j) i.e coordinates of the upper left corner.
        h (int): Height of the cropped region.
        w (int): Width of the cropped region.
        size (tuple(int, int)): height and width of resized clip
    Returns:
        clip (torch.tensor): Resized and cropped clip. Size is (T, C, H, W)
    """
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    clip = crop(clip, i, j, h, w)
    clip = resize(clip, size, interpolation_mode)
    return clip


def center_crop(clip, crop_size):
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    h, w = clip.size(-2), clip.size(-1)
    th, tw = crop_size
    if h < th or w < tw:
        raise ValueError("height and width must be no smaller than crop_size")

    i = int(round((h - th) / 2.0))
    j = int(round((w - tw) / 2.0))
    return crop(clip, i, j, th, tw)


def center_crop_using_short_edge(clip):
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    h, w = clip.size(-2), clip.size(-1)
    if h < w:
        th, tw = h, h
        i = 0
        j = int(round((w - tw) / 2.0))
    else:
        th, tw = w, w
        i = int(round((h - th) / 2.0))
        j = 0
    return crop(clip, i, j, th, tw)


def resize_crop_to_fill(clip, target_size):
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    h, w = clip.size(-2), clip.size(-1)
    th, tw = target_size[0], target_size[1]
    rh, rw = th / h, tw / w
    if rh > rw:
        sh, sw = th, round(w * rh)
        clip = resize(clip, (sh, sw), "bilinear")
        i = 0
        j = int(round(sw - tw) / 2.0)
    else:
        sh, sw = round(h * rw), tw
        clip = resize(clip, (sh, sw), "bilinear")
        i = int(round(sh - th) / 2.0)
        j = 0
    assert i + th <= clip.size(-2) and j + tw <= clip.size(-1)
    return crop(clip, i, j, th, tw)


def random_shift_crop(clip):
    """
    Slide along the long edge, with the short edge as crop size
    """
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    h, w = clip.size(-2), clip.size(-1)

    if h <= w:
        short_edge = h
    else:
        short_edge = w

    th, tw = short_edge, short_edge

    i = torch.randint(0, h - th + 1, size=(1,)).item()
    j = torch.randint(0, w - tw + 1, size=(1,)).item()
    return crop(clip, i, j, th, tw)


def to_tensor(clip):
    """
    Convert tensor data type from uint8 to float, divide value by 255.0 and
    permute the dimensions of clip tensor
    Args:
        clip (torch.tensor, dtype=torch.uint8): Size is (T, C, H, W)
    Return:
        clip (torch.tensor, dtype=torch.float): Size is (T, C, H, W)
    """
    _is_tensor_video_clip(clip)
    if not clip.dtype == torch.uint8:
        raise TypeError("clip tensor should have data type uint8. Got %s" % str(clip.dtype))
    # return clip.float().permute(3, 0, 1, 2) / 255.0
    return clip.float() / 255.0


def normalize(clip, mean, std, inplace=False):
    """
    Args:
        clip (torch.tensor): Video clip to be normalized. Size is (T, C, H, W)
        mean (tuple): pixel RGB mean. Size is (3)
        std (tuple): pixel standard deviation. Size is (3)
    Returns:
        normalized clip (torch.tensor): Size is (T, C, H, W)
    """
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    if not inplace:
        clip = clip.clone()
    mean = torch.as_tensor(mean, dtype=clip.dtype, device=clip.device)
    # print(mean)
    std = torch.as_tensor(std, dtype=clip.dtype, device=clip.device)
    clip.sub_(mean[:, None, None, None]).div_(std[:, None, None, None])
    return clip


def hflip(clip):
    """
    Args:
        clip (torch.tensor): Video clip to be normalized. Size is (T, C, H, W)
    Returns:
        flipped clip (torch.tensor): Size is (T, C, H, W)
    """
    if not _is_tensor_video_clip(clip):
        raise ValueError("clip should be a 4D torch.tensor")
    return clip.flip(-1)


class ResizeCrop:
    def __init__(self, size):
        if isinstance(size, numbers.Number):
            self.size = (int(size), int(size))
        else:
            self.size = size

    def __call__(self, clip):
        clip = resize_crop_to_fill(clip, self.size)
        return clip

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(size={self.size})"


class RandomCropVideo:
    def __init__(self, size):
        if isinstance(size, numbers.Number):
            self.size = (int(size), int(size))
        else:
            self.size = size

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor): Video clip to be cropped. Size is (T, C, H, W)
        Returns:
            torch.tensor: randomly cropped video clip.
                size is (T, C, OH, OW)
        """
        i, j, h, w = self.get_params(clip)
        return crop(clip, i, j, h, w)

    def get_params(self, clip):
        h, w = clip.shape[-2:]
        th, tw = self.size

        if h < th or w < tw:
            raise ValueError(f"Required crop size {(th, tw)} is larger than input image size {(h, w)}")

        if w == tw and h == th:
            return 0, 0, h, w

        i = torch.randint(0, h - th + 1, size=(1,)).item()
        j = torch.randint(0, w - tw + 1, size=(1,)).item()

        return i, j, th, tw

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(size={self.size})"


class CenterCropResizeVideo:
    """
    First use the short side for cropping length,
    center crop video, then resize to the specified size
    """

    def __init__(
        self,
        size,
        interpolation_mode="bilinear",
    ):
        if isinstance(size, tuple):
            if len(size) != 2:
                raise ValueError(f"size should be tuple (height, width), instead got {size}")
            self.size = size
        else:
            self.size = (size, size)

        self.interpolation_mode = interpolation_mode

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor): Video clip to be cropped. Size is (T, C, H, W)
        Returns:
            torch.tensor: scale resized / center cropped video clip.
                size is (T, C, crop_size, crop_size)
        """
        clip_center_crop = center_crop_using_short_edge(clip)
        clip_center_crop_resize = resize(
            clip_center_crop, target_size=self.size, interpolation_mode=self.interpolation_mode
        )
        return clip_center_crop_resize

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(size={self.size}, interpolation_mode={self.interpolation_mode}"


class UCFCenterCropVideo:
    """
    First scale to the specified size in equal proportion to the short edge,
    then center cropping
    """

    def __init__(
        self,
        size,
        interpolation_mode="bilinear",
    ):
        if isinstance(size, tuple):
            if len(size) != 2:
                raise ValueError(f"size should be tuple (height, width), instead got {size}")
            self.size = size
        else:
            self.size = (size, size)

        self.interpolation_mode = interpolation_mode

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor): Video clip to be cropped. Size is (T, C, H, W)
        Returns:
            torch.tensor: scale resized / center cropped video clip.
                size is (T, C, crop_size, crop_size)
        """
        clip_resize = resize_scale(clip=clip, target_size=self.size, interpolation_mode=self.interpolation_mode)
        clip_center_crop = center_crop(clip_resize, self.size)
        return clip_center_crop

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(size={self.size}, interpolation_mode={self.interpolation_mode}"


class KineticsRandomCropResizeVideo:
    """
    Slide along the long edge, with the short edge as crop size. And resie to the desired size.
    """

    def __init__(
        self,
        size,
        interpolation_mode="bilinear",
    ):
        if isinstance(size, tuple):
            if len(size) != 2:
                raise ValueError(f"size should be tuple (height, width), instead got {size}")
            self.size = size
        else:
            self.size = (size, size)

        self.interpolation_mode = interpolation_mode

    def __call__(self, clip):
        clip_random_crop = random_shift_crop(clip)
        clip_resize = resize(clip_random_crop, self.size, self.interpolation_mode)
        return clip_resize


class CenterCropVideo:
    def __init__(
        self,
        size,
        interpolation_mode="bilinear",
    ):
        if isinstance(size, tuple):
            if len(size) != 2:
                raise ValueError(f"size should be tuple (height, width), instead got {size}")
            self.size = size
        else:
            self.size = (size, size)

        self.interpolation_mode = interpolation_mode

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor): Video clip to be cropped. Size is (T, C, H, W)
        Returns:
            torch.tensor: center cropped video clip.
                size is (T, C, crop_size, crop_size)
        """
        clip_center_crop = center_crop(clip, self.size)
        return clip_center_crop

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(size={self.size}, interpolation_mode={self.interpolation_mode}"


class NormalizeVideo:
    """
    Normalize the video clip by mean subtraction and division by standard deviation
    Args:
        mean (3-tuple): pixel RGB mean
        std (3-tuple): pixel RGB standard deviation
        inplace (boolean): whether do in-place normalization
    """

    def __init__(self, mean, std, inplace=False):
        self.mean = mean
        self.std = std
        self.inplace = inplace

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor): video clip must be normalized. Size is (C, T, H, W)
        """
        return normalize(clip, self.mean, self.std, self.inplace)

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(mean={self.mean}, std={self.std}, inplace={self.inplace})"


class ToTensorVideo:
    """
    Convert tensor data type from uint8 to float, divide value by 255.0 and
    permute the dimensions of clip tensor
    """

    def __init__(self):
        pass

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor, dtype=torch.uint8): Size is (T, C, H, W)
        Return:
            clip (torch.tensor, dtype=torch.float): Size is (T, C, H, W)
        """
        return to_tensor(clip)

    def __repr__(self) -> str:
        return self.__class__.__name__


class RandomHorizontalFlipVideo:
    """
    Flip the video clip along the horizontal direction with a given probability
    Args:
        p (float): probability of the clip being flipped. Default value is 0.5
    """

    def __init__(self, p=0.5):
        self.p = p

    def __call__(self, clip):
        """
        Args:
            clip (torch.tensor): Size is (T, C, H, W)
        Return:
            clip (torch.tensor): Size is (T, C, H, W)
        """
        if random.random() < self.p:
            clip = hflip(clip)
        return clip

    def __repr__(self) -> str:
        return f"{self.__class__.__name__}(p={self.p})"


#  ------------------------------------------------------------
#  ---------------------  Sampling  ---------------------------
#  ------------------------------------------------------------
class TemporalRandomCrop(object):
    """Temporally crop the given frame indices at a random location.

    Args:
            size (int): Desired length of frames will be seen in the model.
    """

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

    def __call__(self, total_frames):
        rand_end = max(0, total_frames - self.size - 1)
        begin_index = random.randint(0, rand_end)
        end_index = min(begin_index + self.size, total_frames)
        return begin_index, end_index


def is_img(path):
    ext = os.path.splitext(path)[-1].lower()
    return ext in IMG_EXTENSIONS


def is_vid(path):
    ext = os.path.splitext(path)[-1].lower()
    return ext in VID_EXTENSIONS


def is_url(url):
    return re.match(regex, url) is not None


def read_file(input_path):
    if input_path.endswith(".csv"):
        return pd.read_csv(input_path)
    elif input_path.endswith(".parquet"):
        return pd.read_parquet(input_path)
    else:
        raise NotImplementedError(f"Unsupported file format: {input_path}")


def download_url(input_path):
    output_dir = "cache"
    os.makedirs(output_dir, exist_ok=True)
    base_name = os.path.basename(input_path)
    output_path = os.path.join(output_dir, base_name)
    img_data = requests.get(input_path).content
    with open(output_path, "wb") as handler:
        handler.write(img_data)
    print(f"URL {input_path} downloaded to {output_path}")
    return output_path


def temporal_random_crop(vframes, num_frames, frame_interval):
    temporal_sample = TemporalRandomCrop(num_frames * frame_interval)
    total_frames = len(vframes)
    start_frame_ind, end_frame_ind = temporal_sample(total_frames)
    assert (
        end_frame_ind - start_frame_ind >= num_frames
    ), f"Not enough frames to sample, {end_frame_ind} - {start_frame_ind} < {num_frames}"
    frame_indice = np.linspace(start_frame_ind, end_frame_ind - 1, num_frames, dtype=int)
    video = vframes[frame_indice]
    return video


def get_transforms_video(name="center", image_size=(256, 256)):
    if name is None:
        return None
    elif name == "center":
        assert image_size[0] == image_size[1], "image_size must be square for center crop"
        transform_video = transforms.Compose(
            [
                ToTensorVideo(),  # TCHW
                # video_transforms.RandomHorizontalFlipVideo(),
                UCFCenterCropVideo(image_size[0]),
                transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5], inplace=True),
            ]
        )
    elif name == "resize_crop":
        transform_video = transforms.Compose(
            [
                ToTensorVideo(),  # TCHW
                ResizeCrop(image_size),
                transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5], inplace=True),
            ]
        )
    else:
        raise NotImplementedError(f"Transform {name} not implemented")
    return transform_video


def get_transforms_image(name="center", image_size=(256, 256)):
    if name is None:
        return None
    elif name == "center":
        assert image_size[0] == image_size[1], "Image size must be square for center crop"
        transform = transforms.Compose(
            [
                transforms.Lambda(lambda pil_image: center_crop_arr(pil_image, image_size[0])),
                # transforms.RandomHorizontalFlip(),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5], inplace=True),
            ]
        )
    elif name == "resize_crop":
        transform = transforms.Compose(
            [
                transforms.Lambda(lambda pil_image: resize_crop_to_fill(pil_image, image_size)),
                transforms.ToTensor(),
                transforms.Normalize(mean=[0.5, 0.5, 0.5], std=[0.5, 0.5, 0.5], inplace=True),
            ]
        )
    else:
        raise NotImplementedError(f"Transform {name} not implemented")
    return transform


def read_image_from_path(path, transform=None, transform_name="center", num_frames=1, image_size=(256, 256)):
    image = pil_loader(path)
    if transform is None:
        transform = get_transforms_image(image_size=image_size, name=transform_name)
    image = transform(image)
    video = image.unsqueeze(0).repeat(num_frames, 1, 1, 1)
    video = video.permute(1, 0, 2, 3)
    return video


def read_video_from_path(path, transform=None, transform_name="center", image_size=(256, 256)):
    vframes, aframes, info = torchvision.io.read_video(filename=path, pts_unit="sec", output_format="TCHW")
    if transform is None:
        transform = get_transforms_video(image_size=image_size, name=transform_name)
    video = transform(vframes)  # T C H W
    video = video.permute(1, 0, 2, 3)
    return video


def read_from_path(path, image_size, transform_name="center"):
    if is_url(path):
        path = download_url(path)
    ext = os.path.splitext(path)[-1].lower()
    if ext.lower() in VID_EXTENSIONS:
        return read_video_from_path(path, image_size=image_size, transform_name=transform_name)
    else:
        assert ext.lower() in IMG_EXTENSIONS, f"Unsupported file format: {ext}"
        return read_image_from_path(path, image_size=image_size, transform_name=transform_name)


def save_sample(x, save_path=None, fps=8, normalize=True, value_range=(-1, 1), force_video=False, verbose=True):
    """
    Args:
        x (Tensor): shape [C, T, H, W]
    """
    assert x.ndim == 4

    if not force_video and x.shape[1] == 1:  # T = 1: save as image
        save_path += ".png"
        x = x.squeeze(1)
        save_image([x], save_path, normalize=normalize, value_range=value_range)
    else:
        save_path += ".mp4"
        if normalize:
            low, high = value_range
            x.clamp_(min=low, max=high)
            x.sub_(low).div_(max(high - low, 1e-5))

        x = x.mul(255).add_(0.5).clamp_(0, 255).permute(1, 2, 3, 0).to("cpu", torch.uint8)
        write_video(save_path, x, fps=fps, video_codec="h264")
    if verbose:
        print(f"Saved to {save_path}")
    return save_path


def center_crop_arr(pil_image, image_size):
    """
    Center cropping implementation from ADM.
    https://github.com/openai/guided-diffusion/blob/8fb3ad9197f16bbc40620447b2742e13458d2831/guided_diffusion/image_datasets.py#L126
    """
    while min(*pil_image.size) >= 2 * image_size:
        pil_image = pil_image.resize(tuple(x // 2 for x in pil_image.size), resample=Image.BOX)

    scale = image_size / min(*pil_image.size)
    pil_image = pil_image.resize(tuple(round(x * scale) for x in pil_image.size), resample=Image.BICUBIC)

    arr = np.array(pil_image)
    crop_y = (arr.shape[0] - image_size) // 2
    crop_x = (arr.shape[1] - image_size) // 2
    return Image.fromarray(arr[crop_y : crop_y + image_size, crop_x : crop_x + image_size])


def resize_crop_to_fill(pil_image, image_size):
    w, h = pil_image.size  # PIL is (W, H)
    th, tw = image_size
    rh, rw = th / h, tw / w
    if rh > rw:
        sh, sw = th, round(w * rh)
        image = pil_image.resize((sw, sh), Image.BICUBIC)
        i = 0
        j = int(round((sw - tw) / 2.0))
    else:
        sh, sw = round(h * rw), tw
        image = pil_image.resize((sw, sh), Image.BICUBIC)
        i = int(round((sh - th) / 2.0))
        j = 0
    arr = np.array(image)
    assert i + th <= arr.shape[0] and j + tw <= arr.shape[1]
    return Image.fromarray(arr[i : i + th, j : j + tw])