import numpy as np

from abc import ABC, abstractmethod
from imageio import imread

from . import utils

class BaseMixin(ABC):

	@abstractmethod
	def get_example(self, i):
		pass

	def __getitem__(self, i):
		return self.get_example(i)


class ImageReadMixin(BaseMixin):

	def __init__(self, uuids, annotations, mode="RGB"):
		super(BaseMixin, self).__init__()
		self.uuids = uuids
		self._annot = annotations
		self.mode = mode

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

	def _get(self, method, i):
		return getattr(self._annot, method)(self.uuids[i])

	def get_example(self, i):
		res = super(ImageReadMixin, self).get_example(i)
		# if the super class returns something, then the class inheritance is wrong
		assert res is None, "ImageReadMixin should be the last class in the hierarchy!"

		methods = ["image", "parts", "label"]
		im_path, parts, label = [self._get(m, i) for m in methods]

		im = imread(im_path, pilmode=self.mode)

		return im, parts, label

class BBCropMixin(BaseMixin):

	def __init__(self, crop_to_bb=False, crop_uniform=False, *args, **kwargs):
		super(BBCropMixin, self).__init__(*args, **kwargs)
		self.crop_to_bb = crop_to_bb
		self.crop_uniform = crop_uniform

	def bounding_box(self, i):
		bbox = self._get("bounding_box", i)
		x,y,w,h = [bbox[attr] for attr in "xywh"]
		if self.crop_uniform:
			x0 = x + w//2
			y0 = y + h//2

			crop_size = max(w//2, h//2)

			x,y = max(x0 - crop_size, 0), max(y0 - crop_size, 0)
			w = h = crop_size * 2
		return x,y,w,h

	def get_example(self, i):
		im, parts, label = super(BBCropMixin, self).get_example(i)
		if self.crop_to_bb:
			x,y,w,h = self.bounding_box(i)
			im = im[y:y+h, x:x+w]
			parts[:, 1] -= x
			parts[:, 2] -= y
		return im, parts, label

class UniformPartMixin(BaseMixin):

	def __init__(self, uniform_parts=False, ratio=utils.DEFAULT_RATIO, *args, **kwargs):
		super(UniformPartMixin, self).__init__(*args, **kwargs)
		self.uniform_parts = uniform_parts
		self.ratio = ratio

	def get_example(self, i):
		im, parts, label = super(UniformPartMixin, self).get_example(i)
		if self.uniform_parts:
			parts = utils.uniform_parts(im, ratio=self.ratio)
		return im, parts, label

class RandomBlackOutMixin(BaseMixin):

	def __init__(self, seed=None, rnd_select=False, n_parts=None, *args, **kwargs):
		super(RandomBlackOutMixin, self).__init__(*args, **kwargs)
		self.rnd = np.random.RandomState(seed)
		self.rnd_select = rnd_select
		self.n_parts = n_parts

	def get_example(self, i):
		im, parts, lab = super(RandomBlackOutMixin, self).get_example(i)
		if self.rnd_select:
			idxs, xy = utils.visible_part_locs(parts)
			rnd_idxs = utils.random_idxs(idxs, rnd=self.rnd, n_parts=self.n_parts)

			parts[:, -1] = 0
			parts[rnd_idxs, -1] = 1

		return im, parts, lab

class Dataset(RandomBlackOutMixin, UniformPartMixin, BBCropMixin, ImageReadMixin):
	pass