# Source code for flyforms.validators

    # coding=utf-8
    from abc import ABCMeta, abstractmethod
    from collections import Iterable
    import re

    from flyforms.compatibility import string_types, with_metaclass

    __all__ = (
        "EntryValidator",
        "MaxValueValidator",
        "MaxLengthValidator",
        "MinLengthValidator",
        "MinValueValidator",
        "EmailValidator",
        "RegexValidator",
        "Ip4AddressValidator",
        "RequiredValidator",
        "TypedValidator",
        "ValidationError",
        "UNSET",
        "is_set"
    )

    UNSET = object()  # the default mark for not set values

    is_set = lambda value: value is not UNSET

    class ValidationError(Exception):
        """
        Raised when a validator fails to validate it's input.
        """
        pass

    class Validator(with_metaclass(ABCMeta, object)):
        """
        The abstract root class for all Validators
        """

        message = ""

        @abstractmethod
        def validate(self, value):
            """
            Validate the given value

            :param value: given value to validate

            :raise ValidationError if given value is not valid
            """
            pass

        def __call__(self, value):
            """
            The same with validate
            """
            self.validate(value)

        def is_valid(self, value):
            """
            The 'silent' variant of validation

            :param value: given value to validate

            :return: boolean flag is given value valid
            :rtype: bool
            """
            try:
                self.validate(value)
            except ValidationError:
                return False
            else:
                return True

    class SimpleValidator(with_metaclass(ABCMeta, Validator)):
        """
        The Validator's subclass with only one validation case.
        Given value should satisfies condition in *positive_case* method
        """

        positive_case = abstractmethod(lambda self, x: x is x)  # Given value should satisfies this condition

        def validate(self, value):
            """
            Implementation of Validator's validate method
            """
            try:
                if not self.positive_case(value):   # if positive case wasn't satisfied then ValidationError will be raised
                    raise ValidationError(self.message)
            except TypeError as err:
                raise ValidationError(str(err))

    class RequiredValidator(SimpleValidator):
        """
        Validates is given value not :py:data:`.UNSET` object
        """

        message = "Field is required."

        positive_case = lambda self, value: value is not UNSET

    class TypedValidator(SimpleValidator):
        """
        Validates is given value instance of defined :code:`value_types`
        """

        message = "Bad value type."

        def __init__(self, value_types):
            """
            :param value_types: list of possible value types
            """
            self.value_types = value_types

        positive_case = lambda self, value: isinstance(value, self.value_types) or value is UNSET

    class EntryValidator(SimpleValidator):
        """
        Validates is given value in specified during initialization iterable object
        """

        message = "Value not in choices."

        def __init__(self, iterable):
            """
            :param iterable: the iterable object

            :raise: TypeError if given object is not iterable
            """
            if not isinstance(iterable, Iterable):
                raise TypeError("Entry validator instance need an iterable object")
            self.iterable = iterable

        positive_case = lambda self, value: value in self.iterable

    class MinValueValidator(SimpleValidator):
        """
        Validates is given value greater than specified during initialization value
        """

        message = "Given value is less than minimum valid value."

        def __init__(self, min_value, strong=True):
            """
            :param min_value: the minimum valid value

            :param strong: boolean flag should be comparison strict or not
            :type strong: bool
            """
            self.min_value = min_value
            self.strong = strong

        positive_case = lambda self, value: value > self.min_value if self.strong else value >= self.min_value

    class MaxValueValidator(SimpleValidator):
        """
        Validates is given value less than specified during initialization value
        """

        message = "Given value is greater than maximum valid value."

        def __init__(self, max_value, strong=True):
            """
            :param max_value: the maximum valid value

            :param strong: boolean flag should be comparison strict or not
            :type strong: bool
            """
            self.max_value = max_value
            self.strong = strong

        positive_case = lambda self, value: value < self.max_value if self.strong else value <= self.max_value

    class MinLengthValidator(SimpleValidator):
        """
        Validates the minimum object length
        """

        message = "Value is too short."

        def __init__(self, min_length, strong=True):
            """
            :param min_length: the minimum valid length

            :param strong: boolean flag should be comparison strict or not
            :type strong: bool
            """
            self.len = min_length
            self.strong = strong

        def validate(self, value):
            """
            Implementation of Validator's validate method
            """
            if not hasattr(value, '__len__'):  # check for __len__ attribute
                raise ValidationError("Validation failed because value of type '%s' has no len()" % type(value))
            super(MinLengthValidator, self).validate(
                len(value)
            )

        positive_case = lambda self, value_len: value_len > self.len if self.strong else value_len >= self.len

    class MaxLengthValidator(MinLengthValidator):
        """
        Validates the maximum object length
        """
        message = "Value is too long."

        def __init__(self, max_length, strong=True):
            """
            :param max_length: the maximum valid length

            :param strong: boolean flag should be comparison strict or not
            :type strong: bool
            """
            super(MaxLengthValidator, self).__init__(max_length, strong)

        positive_case = lambda self, value_len: value_len < self.len if self.strong else value_len <= self.len

    class RegexValidator(SimpleValidator):
        """
        Validates matching with regular expression
        """

        message = "Value does not match the regular expression."

        def __init__(self, regex, flags=0):
            """
            :param regex: the regular expression

            :param flags: flags passed to re.match function
            """
            self.r = re.compile(regex, flags)

        def validate(self, value):
            """
            The Validator's validate method implementation
            """
            if not isinstance(value, string_types):
                raise ValidationError("Validation failed because value is not string")
            super(RegexValidator, self).validate(value)

        positive_case = lambda self, value: self.r.match(value)

    class EmailValidator(RegexValidator):
        """
        Validates an email address via simple regex.
        """

        message = "Bad e-mail address"

        def __init__(self):
            super(EmailValidator, self).__init__(
                regex=r"^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+$"
            )

    class Ip4AddressValidator(RegexValidator):
        """
        Validates an IPv4 address via simple regex.
        """

        message = "Bad ip address"

        def __init__(self):
            super(Ip4AddressValidator, self).__init__(
                regex=r"^\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$"
            )