"""Image validators."""

import validation


class ImageValidator(validation.Validator):
    """Validate an image."""

    # TODO(horia141): keep in sync with frontend
    IMAGE_ASPECT_RATIO = 16/9
    IMAGE_MIN_WIDTH = 800
    IMAGE_MIN_HEIGHT = 450
    IMAGE_MAX_WIDTH = 1600
    IMAGE_MAX_HEIGHT = 900
    IMAGE_WIDTH = IMAGE_MAX_WIDTH
    IMAGE_HEIGHT = IMAGE_MAX_HEIGHT

    SCHEMA = {
        '$schema': 'http://json-schema.org/draft-04/schema#',
        'title': 'Image',
        'description': 'An image',
        'type': 'object',
        'properties': {
            'orderNo': {
                'description': 'The order in which the image appears for display',
                'type': 'integer',
                'minimum': 0
            },
            'uri': {
                'description': 'The URI where the image can be retrieved',
                'type': 'string',
            },
            'width': {
                'description': 'The width of the image',
                'type': 'integer',
                'minimum': IMAGE_MIN_WIDTH,
                'maximum': IMAGE_MAX_WIDTH
            },
            'height': {
                'description': 'The height of the image',
                'type': 'integer',
                'minimum': IMAGE_MIN_HEIGHT,
                'maximum': IMAGE_MAX_HEIGHT
            }
        },
        'required': ['orderNo', 'uri', 'width', 'height'],
        'additionalProperties': False
    }

    def _post_schema_validate(self, image_raw):
        image = dict(image_raw)
        image['uri'] = image['uri'].strip()

        if image['uri'] == '':
            raise validation.Error('Image set url is empty')

        return image


class ImageSetValidator(validation.Validator):
    """Validate an image set."""

    SCHEMA = {
        '$schema': 'http://json-schema.org/draft-04/schema#',
        'title': 'Image set',
        'description': 'A set of images',
        'type': 'array',
        'items': ImageValidator.SCHEMA,
        'additionalItems': False
    }

    def __init__(self, image_validator):
        self._image_validator = image_validator

    def _post_schema_validate(self, image_set_raw):
        image_set = []

        for i in range(len(image_set_raw)):
            image = self._image_validator.validate(image_set_raw[i])
                
            if image['orderNo'] != i:
                raise validation.Error('Image set not properly ordered')

            image_set.append(image)

        return image_set