"""
Field classes.
"""

from __future__ import unicode_literals

import copy
import datetime
import os
import re
import sys
import uuid
import warnings
from decimal import Decimal, DecimalException
from io import BytesIO

from django.core import validators
from django.core.exceptions import ValidationError
# Provide this import for backwards compatibility.
from django.core.validators import EMPTY_VALUES  # NOQA
from django.forms.boundfield import BoundField
from django.forms.utils import from_current_timezone, to_current_timezone
from django.forms.widgets import (
    FILE_INPUT_CONTRADICTION, CheckboxInput, ClearableFileInput, DateInput,
    DateTimeInput, EmailInput, HiddenInput, MultipleHiddenInput,
    NullBooleanSelect, NumberInput, Select, SelectMultiple,
    SplitDateTimeWidget, SplitHiddenDateTimeWidget, TextInput, TimeInput,
    URLInput,
)
from django.utils import formats, six
from django.utils.dateparse import parse_duration
from django.utils.deprecation import (
    RemovedInDjango110Warning, RenameMethodsBase,
)
from django.utils.duration import duration_string
from django.utils.encoding import force_str, force_text, smart_text
from django.utils.ipv6 import clean_ipv6_address
from django.utils.six.moves.urllib.parse import urlsplit, urlunsplit
from django.utils.translation import ugettext_lazy as _, ungettext_lazy

__all__ = (
    'Field', 'CharField', 'IntegerField',
    'DateField', 'TimeField', 'DateTimeField', 'DurationField',
    'RegexField', 'EmailField', 'FileField', 'ImageField', 'URLField',
    'BooleanField', 'NullBooleanField', 'ChoiceField', 'MultipleChoiceField',
    'ComboField', 'MultiValueField', 'FloatField', 'DecimalField',
    'SplitDateTimeField', 'GenericIPAddressField', 'FilePathField',
    'SlugField', 'TypedChoiceField', 'TypedMultipleChoiceField', 'UUIDField',
)


class RenameFieldMethods(RenameMethodsBase):
    renamed_methods = (
        ('_has_changed', 'has_changed', RemovedInDjango110Warning),
    )


class Field(six.with_metaclass(RenameFieldMethods, object)):
    widget = TextInput  # Default widget to use when rendering this type of Field.
    hidden_widget = HiddenInput  # Default widget to use when rendering this as "hidden".
    default_validators = []  # Default set of validators
    # Add an 'invalid' entry to default_error_message if you want a specific
    # field error message not raised by the field validators.
    default_error_messages = {
        'required': _('This field is required.'),
    }
    empty_values = list(validators.EMPTY_VALUES)

    # Tracks each time a Field instance is created. Used to retain order.
    creation_counter = 0

    def __init__(self, required=True, widget=None, label=None, initial=None,
                 help_text='', error_messages=None, show_hidden_initial=False,
                 validators=[], localize=False, disabled=False, label_suffix=None):
        # required -- Boolean that specifies whether the field is required.
        #             True by default.
        # widget -- A Widget class, or instance of a Widget class, that should
        #           be used for this Field when displaying it. Each Field has a
        #           default Widget that it'll use if you don't specify this. In
        #           most cases, the default widget is TextInput.
        # label -- A verbose name for this field, for use in displaying this
        #          field in a form. By default, Django will use a "pretty"
        #          version of the form field name, if the Field is part of a
        #          Form.
        # initial -- A value to use in this Field's initial display. This value
        #            is *not* used as a fallback if data isn't given.
        # help_text -- An optional string to use as "help text" for this Field.
        # error_messages -- An optional dictionary to override the default
        #                   messages that the field will raise.
        # show_hidden_initial -- Boolean that specifies if it is needed to render a
        #                        hidden widget with initial value after widget.
        # validators -- List of additional validators to use
        # localize -- Boolean that specifies if the field should be localized.
        # disabled -- Boolean that specifies whether the field is disabled, that
        #             is its widget is shown in the form but not editable.
        # label_suffix -- Suffix to be added to the label. Overrides
        #                 form's label_suffix.
        self.required, self.label, self.initial = required, label, initial
        self.show_hidden_initial = show_hidden_initial
        self.help_text = help_text
        self.disabled = disabled
        self.label_suffix = label_suffix
        widget = widget or self.widget
        if isinstance(widget, type):
            widget = widget()

        # Trigger the localization machinery if needed.
        self.localize = localize
        if self.localize:
            widget.is_localized = True

        # Let the widget know whether it should display as required.
        widget.is_required = self.required

        # Hook into self.widget_attrs() for any Field-specific HTML attributes.
        extra_attrs = self.widget_attrs(widget)
        if extra_attrs:
            widget.attrs.update(extra_attrs)

        self.widget = widget

        # Increase the creation counter, and save our local copy.
        self.creation_counter = Field.creation_counter
        Field.creation_counter += 1

        messages = {}
        for c in reversed(self.__class__.__mro__):
            messages.update(getattr(c, 'default_error_messages', {}))
        messages.update(error_messages or {})
        self.error_messages = messages

        self.validators = self.default_validators + validators
        super(Field, self).__init__()

    def prepare_value(self, value):
        return value

    def to_python(self, value):
        return value

    def validate(self, value):
        if value in self.empty_values and self.required:
            raise ValidationError(self.error_messages['required'], code='required')

    def run_validators(self, value):
        if value in self.empty_values:
            return
        errors = []
        for v in self.validators:
            try:
                v(value)
            except ValidationError as e:
                if hasattr(e, 'code') and e.code in self.error_messages:
                    e.message = self.error_messages[e.code]
                errors.extend(e.error_list)
        if errors:
            raise ValidationError(errors)

    def clean(self, value):
        """
        Validates the given value and returns its "cleaned" value as an
        appropriate Python object.

        Raises ValidationError for any errors.
        """
        value = self.to_python(value)
        self.validate(value)
        self.run_validators(value)
        return value

    def bound_data(self, data, initial):
        """
        Return the value that should be shown for this field on render of a
        bound form, given the submitted POST data for the field and the initial
        data, if any.

        For most fields, this will simply be data; FileFields need to handle it
        a bit differently.
        """
        if self.disabled:
            return initial
        return data

    def widget_attrs(self, widget):
        """
        Given a Widget instance (*not* a Widget class), returns a dictionary of
        any HTML attributes that should be added to the Widget, based on this
        Field.
        """
        return {}

    def has_changed(self, initial, data):
        """
        Return True if data differs from initial.
        """
        try:
            data = self.to_python(data)
            if hasattr(self, '_coerce'):
                return self._coerce(data) != self._coerce(initial)
        except ValidationError:
            return True
        # For purposes of seeing whether something has changed, None is
        # the same as an empty string, if the data or initial value we get
        # is None, replace it with ''.
        initial_value = initial if initial is not None else ''
        data_value = data if data is not None else ''
        return initial_value != data_value

    def get_bound_field(self, form, field_name):
        """
        Return a BoundField instance that will be used when accessing the form
        field in a template.
        """
        return BoundField(form, self, field_name)

    def __deepcopy__(self, memo):
        result = copy.copy(self)
        memo[id(self)] = result
        result.widget = copy.deepcopy(self.widget, memo)
        result.validators = self.validators[:]
        return result


class CharField(Field):
    def __init__(self, max_length=None, min_length=None, strip=True, *args, **kwargs):
        self.max_length = max_length
        self.min_length = min_length
        self.strip = strip
        super(CharField, self).__init__(*args, **kwargs)
        if min_length is not None:
            self.validators.append(validators.MinLengthValidator(int(min_length)))
        if max_length is not None:
            self.validators.append(validators.MaxLengthValidator(int(max_length)))

    def to_python(self, value):
        "Returns a Unicode object."
        if value in self.empty_values:
            return ''
        value = force_text(value)
        if self.strip:
            value = value.strip()
        return value

    def widget_attrs(self, widget):
        attrs = super(CharField, self).widget_attrs(widget)
        if self.max_length is not None:
            # The HTML attribute is maxlength, not max_length.
            attrs.update({'maxlength': str(self.max_length)})
        return attrs


class IntegerField(Field):
    widget = NumberInput
    default_error_messages = {
        'invalid': _('Enter a whole number.'),
    }
    re_decimal = re.compile(r'\.0*\s*$')

    def __init__(self, max_value=None, min_value=None, *args, **kwargs):
        self.max_value, self.min_value = max_value, min_value
        if kwargs.get('localize') and self.widget == NumberInput:
            # Localized number input is not well supported on most browsers
            kwargs.setdefault('widget', super(IntegerField, self).widget)
        super(IntegerField, self).__init__(*args, **kwargs)

        if max_value is not None:
            self.validators.append(validators.MaxValueValidator(max_value))
        if min_value is not None:
            self.validators.append(validators.MinValueValidator(min_value))

    def to_python(self, value):
        """
        Validates that int() can be called on the input. Returns the result
        of int(). Returns None for empty values.
        """
        value = super(IntegerField, self).to_python(value)
        if value in self.empty_values:
            return None
        if self.localize:
            value = formats.sanitize_separators(value)
        # Strip trailing decimal and zeros.
        try:
            value = int(self.re_decimal.sub('', str(value)))
        except (ValueError, TypeError):
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        return value

    def widget_attrs(self, widget):
        attrs = super(IntegerField, self).widget_attrs(widget)
        if isinstance(widget, NumberInput):
            if self.min_value is not None:
                attrs['min'] = self.min_value
            if self.max_value is not None:
                attrs['max'] = self.max_value
        return attrs


class FloatField(IntegerField):
    default_error_messages = {
        'invalid': _('Enter a number.'),
    }

    def to_python(self, value):
        """
        Validates that float() can be called on the input. Returns the result
        of float(). Returns None for empty values.
        """
        value = super(IntegerField, self).to_python(value)
        if value in self.empty_values:
            return None
        if self.localize:
            value = formats.sanitize_separators(value)
        try:
            value = float(value)
        except (ValueError, TypeError):
            raise ValidationError(self.error_messages['invalid'], code='invalid')
        return value

    def validate(self, value):
        super(FloatField, self).validate(value)

        # Check for NaN (which is the only thing not equal to itself) and +/- infinity
        if value != value or value in (Decimal('Inf'), Decimal('-Inf')):
            raise ValidationError(self.error_messages['invalid'], code='invalid')

        return value

    def widget_attrs(self, widget):
        attrs = super(FloatField, self).widget_attrs(widget)
        if isinstance(widget, NumberInput) and 'step' not in widget.attrs:
            attrs.setdefault('step', 'any')
        return attrs


class DecimalField(IntegerField):
    default_error_messages = {
        'invalid': _('Enter a number.'),
    }

    def __init__(self, max_value=None, min_value=None, max_digits=None, decimal_places=None, *args, **kwargs):
        self.max_digits, self.decimal_places = max_digits, decimal_places
        super(DecimalField, self).__init__(max_value, min_value, *args, **kwargs)
        self.validators.append(validators.DecimalValidator(max_digits, decimal_places))

    def to_python(self, value):