import json
import logging
from datetime import datetime

import pytz
from PIL import Image, IptcImagePlugin, TiffImagePlugin

logger = logging.getLogger(__name__)


""" Required exif values """
TAGS_EXIF = {
    0x9003: "DateTimeOriginal",
    0x829D: "FNumber",
    0x829A: "ExposureTime",
    0x8827: "ISOSpeedRatings",
    0x9204: "ExposureBiasValue",
    0x8822: "ExposureProgram",
    0x9207: "MeteringMode",
    0x920A: "FocalLength",
    0xA405: "FocalLengthIn35mmFilm",
    0x0110: "Model",
    0xA434: "LensModel",
}

""" Required iptc values """
TAGS_IPTC = {
    (2, 25): "Keywords",
    (2, 55): "DateCreated",
    (2, 60): "TimeCreated",
}


class Exif:

    def __init__(self, filename: str):

        self.filename = filename
        self._exif = {}
        self._iptc = {}
        self.data = {}

        """ Open image file """
        try:
            with Image.open(self.filename) as self.img:
                self.img.verify()
        except Exception:
            logger.exception('Could not open image: %s', self.filename)

        """ Read exif tags """
        try:
            self._exif = {
                TAGS_EXIF[k]: v
                for k, v in self.img._getexif().items()
                if k in TAGS_EXIF
            }
            for (key, value) in self._exif.items():
                if isinstance(value, TiffImagePlugin.IFDRational):
                    self.data[key] = float(value)
                elif isinstance(value, tuple):
                    self.data[key] = tuple(float(t) if isinstance(t, TiffImagePlugin.IFDRational) else t for t in value)
                elif isinstance(value, bytes):
                    self.data[key] = value.decode('utf-8')
                else:
                    self.data[key] = value
        except Exception:
            logger.warning('Could not read exif metadata from: %s', self.filename)

        """ Read iptc tags """
        try:
            self._iptc = {
                TAGS_IPTC[k]: v
                for k, v in IptcImagePlugin.getiptcinfo(self.img).items()
                if k in TAGS_IPTC
            }
            for (key, value) in self._iptc.items():
                if isinstance(value, list):
                    self.data[key] = [x.decode('utf-8') for x in value]
                else:
                    self.data[key] = value.decode('utf-8')
        except Exception:
            logger.warning('Could not read iptc metadata from: %s', self.filename)

    def datetimeoriginal(self, timezone='UTC'):
        """ Return DateTimeOriginal with timezone """
        if 'DateTimeOriginal' in self.data:
            try:
                return datetime.strptime(self.data['DateTimeOriginal'], "%Y:%m:%d %H:%M:%S").astimezone(pytz.timezone(timezone))
            except ValueError as e:
                logger.warning('Could not parse date from: %s', self.filename)
        else:
            return datetime.now(pytz.timezone(timezone))

    def json(self):
        """ Return exif data in json format """
        return json.dumps(self.data)

    def keywords(self):
        """ Return Keywords list """
        if 'Keywords' not in self.data:
            return []
        if type(self.data['Keywords']) == list:
            return self.data['Keywords']
        return [self.data['Keywords']]

    def __str__(self):
        return self.filename