import logging
from os import listdir
from os.path import splitext
from pathlib import Path

import albumentations as A
import numpy as np
import torch
from PIL import Image
from torch.utils.data import Dataset


class SphereDataset(Dataset):
    def __init__(self, images_dir: str, transform: A.Compose, masks_dir: str = None):
        self.images_dir = Path(images_dir)
        self.masks_dir = Path(masks_dir) if masks_dir else None

        self.ids = [splitext(file)[0] for file in listdir(images_dir) if not file.startswith(".")]

        if not self.ids:
            raise RuntimeError(f"No input file found in {images_dir}, make sure you put your images there")

        logging.info(f"Creating dataset with {len(self.ids)} examples")

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

    @staticmethod
    def preprocess(pil_img, scale, is_mask):
        w, h = pil_img.size
        newW, newH = int(scale * w), int(scale * h)

        assert newW > 0 and newH > 0, "Scale is too small, resized images would have no pixel"

        pil_img = pil_img.resize((newW, newH), resample=Image.NEAREST if is_mask else Image.BICUBIC)
        img_ndarray = np.asarray(pil_img)

        if not is_mask:
            if img_ndarray.ndim == 2:
                img_ndarray = img_ndarray[np.newaxis, ...]
            else:
                img_ndarray = img_ndarray.transpose((2, 0, 1))

            img_ndarray = img_ndarray / 255

        return img_ndarray

    @staticmethod
    def load(filename):
        ext = splitext(filename)[1]

        if ext in [".npz", ".npy"]:
            return Image.fromarray(np.load(filename))
        elif ext in [".pt", ".pth"]:
            return Image.fromarray(torch.load(filename).numpy())
        else:
            return Image.open(filename)

    def __getitem__(self, idx):
        name = self.ids[idx]

        mask_file = list(self.masks_dir.glob(name + self.mask_suffix + ".*"))
        img_file = list(self.images_dir.glob(name + ".*"))

        assert len(img_file) == 1, f"Either no image or multiple images found for the ID {name}: {img_file}"
        assert len(mask_file) == 1, f"Either no mask or multiple masks found for the ID {name}: {mask_file}"

        mask = self.load(mask_file[0])
        img = self.load(img_file[0])

        assert (
            img.size == mask.size
        ), f"Image and mask {name} should be the same size, but are {img.size} and {mask.size}"

        img = self.preprocess(img, self.scale, is_mask=False)
        mask = self.preprocess(mask, self.scale, is_mask=True)

        return {
            "image": torch.as_tensor(img.copy()).float().contiguous(),
            "mask": torch.as_tensor(mask.copy()).long().contiguous(),
        }