"""

This class provides a unified interface decoding various slide formats.

Cancheng Liu

Email: liucancheng@thorough.ai

"""

import os.path

from openslide import OpenSlide

from utils import config

class Slide(object):

    def __init__(self, image_path):

        super(Slide, self).__init__()

        self.image_path = image_path.strip()

        self.image_file = os.path.basename(image_path)

        self.image_name, self.suffix = self.image_file.split('.')

        if not self.suffix in config.format_mapping.keys():

            raise Exception('Error: File format ' + self.suffix + ' is supported yet.')

        self._slide = OpenSlide(image_path)

        self._level_downsamples = self._slide.level_downsamples

        self._level_dimensions = self._slide.level_dimensions

        self.width, self.height = self._level_dimensions[0]

    @property

    def dimensions(self):

        return self._level_dimensions[0]

    @property

    def level_dimensions(self):

        return self._level_dimensions

    @property

    def level_downsamples(self):

        return self._level_downsamples

    def read_region(self, level, location, size):

        (x, y), (w, h) = location, size

        try:

            _ds = self._level_downsamples[level]

            patch = self._slide.read_region(

                level=level, location=(int(x * _ds), int(y * _ds)), size=size)

        except Exception:

            raise

        else:

            return patch

    def get_thumbnail(self):

        try:

            image = self._slide.read_region(

                location=(0, 0), level=0, size=(1000, 1000))

        except Exception:

            raise

        else:

            return image