import imghdr
import base64
import six
import uuid

from django.core.files.base import ContentFile

from rest_framework import serializers, viewsets
from rest_framework.response import Response

# https://gist.github.com/ivlevdenis/a0c8f5b472b6b8550bbb016c6a30e0be


class ExtendViewSet(object):
    """
    This viewset mixin class with extended options list.
    """
    permission_map = {}
    throttle_scope_map = {}
    serializer_class_map = {}

    def get_serializer_class(self):
        ser = self.serializer_class_map.get(self.action, None)
        self.serializer_class = ser or self.serializer_class
        return super().get_serializer_class()

    def initialize_request(self, request, *args, **kwargs):
        request = super().initialize_request(request, *args, **kwargs)
        throttle_scope = self.throttle_scope_map.get(self.action, None)
        cls_throttle_scope = getattr(self, 'throttle_scope', None)
        self.throttle_scope = throttle_scope or cls_throttle_scope or ''
        return request

    def get_permissions(self):
        perms = self.permission_map.get(self.action, None)
        if perms and not isinstance(perms, (tuple, list)):
            perms = [perms, ]
        self.permission_classes = perms or self.permission_classes
        return super().get_permissions()

    def options(self, request, *args, **kwargs):
        if self.metadata_class is None:
            return self.http_method_not_allowed(request, *args, **kwargs)
        data = self.metadata_class().determine_metadata(request, self)
        data['actions']['GET'] = self.query_metadata
        return Response(data, status=status.HTTP_200_OK)


class ExtendedModelViewSet(ExtendViewSet, viewsets.ModelViewSet):
    pass


class Base64ImageField(serializers.ImageField):

    def to_internal_value(self, data):
        if isinstance(data, six.string_types):
            if 'data:' in data and ';base64,' in data:
                header, data = data.split(';base64,')
                try:
                    decoded_file = base64.b64decode(data)
                except TypeError:
                    self.fail('invalid_image')

                file_name = str(uuid.uuid4())[:12]
                file_extension = self.get_file_extension(
                    file_name, decoded_file)
                complete_file_name = "%s.%s" % (file_name, file_extension,)
                data = ContentFile(decoded_file, name=complete_file_name)
        return super().to_internal_value(data)

    def get_file_extension(self, file_name, decoded_file):
        extension = imghdr.what(file_name, decoded_file)
        extension = "jpg" if extension == "jpeg" else extension
        return extension