# -*- coding: utf-8 -*-
#
# Licensed to the Apache Software Foundation (ASF) under one
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# regarding copyright ownership.  The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
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# KIND, either express or implied.  See the License for the
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# under the License.

import json

from wtforms.validators import EqualTo, ValidationError


class GreaterEqualThan(EqualTo):
    """Compares the values of two fields.

    :param fieldname:
        The name of the other field to compare to.
    :param message:
        Error message to raise in case of a validation error. Can be
        interpolated with `%(other_label)s` and `%(other_name)s` to provide a
        more helpful error.
    """

    def __call__(self, form, field):
        try:
            other = form[self.fieldname]
        except KeyError:
            raise ValidationError(
                field.gettext("Invalid field name '%s'." % self.fieldname)
            )

        if field.data is None or other.data is None:
            return

        if field.data < other.data:
            d = {
                'other_label':
                    hasattr(other, 'label') and other.label.text or self.fieldname,
                'other_name': self.fieldname,
            }
            message = self.message
            if message is None:
                message = field.gettext('Field must be greater than or equal '
                                        'to %(other_label)s.' % d)
            else:
                message = message % d

            raise ValidationError(message)


class ValidJson(object):
    """Validates data is valid JSON.

    :param message:
        Error message to raise in case of a validation error.
    """
    def __init__(self, message=None):
        self.message = message

    def __call__(self, form, field):
        if field.data:
            try:
                json.loads(field.data)
            except Exception as ex:
                message = self.message or 'JSON Validation Error: {}'.format(ex)
                raise ValidationError(
                    message=field.gettext(message.format(field.data))
                )
