from datetime import datetime

from pathlib import Path


class Exif:
    class Prop:
        def __init__(self, name):
            self.name = name

        def __get__(self, obj: 'Exif', objtype=None):
            if obj is None:
                return self
            return self.fget(obj)

        def fget(self, obj: 'Exif'):
            return obj._raw.get(self.name)

    maker = Prop('Exif:Make')
    model = Prop('Exif:Model')
    lens_model = Prop('Exif:LensModel')
    iso = Prop('Exif:ISO')
    fnumber = Prop('Exif:FNumber')
    exposure_time = Prop('Exif:ExposureTime')
    focal_length = Prop('Exif:FocalLength')
    orientation = Prop('Exif:Orientation')
    style = Prop('MakerNotes:FilmMode')
    datetime_original = Prop('Exif:DateTimeOriginal')

    def __init__(self, raw):
        """
        :type raw: dict
        """
        self.path = Path(raw['SourceFile'])
        self._raw = raw

    @property
    def datetime(self):
        if 'DateTimeOriginal' in self._raw:
            return datetime.strptime(self._raw['DateTimeOriginal'], '%Y:%m:%d %H:%M:%S')
        return None

    def diff(self, other: 'Exif'):
        props = (Exif.maker, Exif.model, Exif.lens_model, Exif.style, Exif.orientation, Exif.datetime_original)
        for p in props:
            self_value = p.fget(self)
            other_value = p.fget(other)
            if self_value != other_value:
                name = p.name.ljust(8, ' ')
                yield f'{name}\t{self_value}\t->\t{other_value}'

    def __eq__(self, other: 'Exif') -> bool:
        props = (
            Exif.maker,
            Exif.model,
            Exif.lens_model,
            Exif.iso,
            Exif.fnumber,
            Exif.exposure_time,
            Exif.focal_length,
            Exif.orientation,
            Exif.style,
            Exif.datetime_original,
        )
        return all(p.fget(self) == p.fget(other) for p in props)


def test_exif():
    raw = {'SourceFile': '123.jpg', 'Exif:ISO': 320, 'Exif:Make': 'Canon'}
    exif = Exif(raw)
    raw2 = dict(raw, **{'Exif:Make': 'Fuji'})
    exi2 = Exif(raw2)

    assert exif.iso == 320
    assert exif == Exif(raw)
    assert exif != exi2
    assert list(exif.diff(exi2)) == ['Exif:Make\tCanon\t->\tFuji']