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from collections import namedtuple
from datetime import datetime, time
from django import forms
from django.utils.dateparse import parse_datetime
from django.utils.encoding import force_str
from django.utils.translation import gettext_lazy as _
from .conf import settings
from .constants import EMPTY_VALUES
from .utils import handle_timezone
from .widgets import (
BaseCSVWidget,
CSVWidget,
DateRangeWidget,
LookupChoiceWidget,
RangeWidget
)
class RangeField(forms.MultiValueField):
widget = RangeWidget
def __init__(self, fields=None, *args, **kwargs):
if fields is None:
fields = (
forms.DecimalField(),
forms.DecimalField())
super().__init__(fields, *args, **kwargs)
def compress(self, data_list):
if data_list:
return slice(*data_list)
return None
class DateRangeField(RangeField):
widget = DateRangeWidget
def __init__(self, *args, **kwargs):
fields = (
forms.DateField(),
forms.DateField())
super().__init__(fields, *args, **kwargs)
def compress(self, data_list):
if data_list:
start_date, stop_date = data_list
if start_date:
start_date = handle_timezone(
datetime.combine(start_date, time.min),
False
)
if stop_date:
stop_date = handle_timezone(
datetime.combine(stop_date, time.max),
False
)
return slice(start_date, stop_date)
return None
class DateTimeRangeField(RangeField):
widget = DateRangeWidget
def __init__(self, *args, **kwargs):
fields = (
forms.DateTimeField(),
forms.DateTimeField())
super().__init__(fields, *args, **kwargs)
class IsoDateTimeRangeField(RangeField):
widget = DateRangeWidget
def __init__(self, *args, **kwargs):
fields = (
IsoDateTimeField(),
IsoDateTimeField())
super().__init__(fields, *args, **kwargs)
class TimeRangeField(RangeField):
widget = DateRangeWidget
def __init__(self, *args, **kwargs):
fields = (
forms.TimeField(),
forms.TimeField())
super().__init__(fields, *args, **kwargs)
class Lookup(namedtuple('Lookup', ('value', 'lookup_expr'))):
def __new__(cls, value, lookup_expr):
if value in EMPTY_VALUES or lookup_expr in EMPTY_VALUES:
raise ValueError(
"Empty values ([], (), {}, '', None) are not "
"valid Lookup arguments. Return None instead."
)
return super().__new__(cls, value, lookup_expr)
class LookupChoiceField(forms.MultiValueField):
default_error_messages = {
'lookup_required': _('Select a lookup.'),
}
def __init__(self, field, lookup_choices, *args, **kwargs):
empty_label = kwargs.pop('empty_label', settings.EMPTY_CHOICE_LABEL)
fields = (field, ChoiceField(choices=lookup_choices, empty_label=empty_label))
widget = LookupChoiceWidget(widgets=[f.widget for f in fields])
kwargs['widget'] = widget
kwargs['help_text'] = field.help_text
super().__init__(fields, *args, **kwargs)
def compress(self, data_list):
if len(data_list) == 2:
value, lookup_expr = data_list
if value not in EMPTY_VALUES:
if lookup_expr not in EMPTY_VALUES:
return Lookup(value=value, lookup_expr=lookup_expr)
else:
raise forms.ValidationError(
self.error_messages['lookup_required'],
code='lookup_required')
return None
class IsoDateTimeField(forms.DateTimeField):
"""
Supports 'iso-8601' date format too which is out the scope of
the ``datetime.strptime`` standard library
# ISO 8601: ``http://www.w3.org/TR/NOTE-datetime``
Based on Gist example by David Medina https://gist.github.com/copitux/5773821
"""
ISO_8601 = 'iso-8601'
input_formats = [ISO_8601]
def strptime(self, value, format):
value = force_str(value)
if format == self.ISO_8601:
parsed = parse_datetime(value)
if parsed is None: # Continue with other formats if doesn't match
raise ValueError
return handle_timezone(parsed)
return super().strptime(value, format)
class BaseCSVField(forms.Field):
"""
Base field for validating CSV types. Value validation is performed by
secondary base classes.
ex::
class IntegerCSVField(BaseCSVField, filters.IntegerField):
pass
"""
base_widget_class = BaseCSVWidget
def __init__(self, *args, **kwargs):
widget = kwargs.get('widget') or self.widget
kwargs['widget'] = self._get_widget_class(widget)
super().__init__(*args, **kwargs)
def _get_widget_class(self, widget):
# passthrough, allows for override
if isinstance(widget, BaseCSVWidget) or (
isinstance(widget, type) and
issubclass(widget, BaseCSVWidget)):
return widget
# complain since we are unable to reconstruct widget instances
assert isinstance(widget, type), \
"'%s.widget' must be a widget class, not %s." \
% (self.__class__.__name__, repr(widget))
bases = (self.base_widget_class, widget, )
return type(str('CSV%s' % widget.__name__), bases, {})
def clean(self, value):
if value is None:
return None
return [super(BaseCSVField, self).clean(v) for v in value]
class BaseRangeField(BaseCSVField):
# Force use of text input, as range must always have two inputs. A date
# input would only allow a user to input one value and would always fail.
widget = CSVWidget
default_error_messages = {
'invalid_values': _('Range query expects two values.')
}
def clean(self, value):
value = super().clean(value)
assert value is None or isinstance(value, list)
if value and len(value) != 2:
raise forms.ValidationError(
self.error_messages['invalid_values'],
code='invalid_values')
return value
class ChoiceIterator:
# Emulates the behavior of ModelChoiceIterator, but instead wraps
# the field's _choices iterable.
def __init__(self, field, choices):
self.field = field
self.choices = choices
def __iter__(self):
if self.field.empty_label is not None:
yield ("", self.field.empty_label)
if self.field.null_label is not None:
yield (self.field.null_value, self.field.null_label)
yield from self.choices
def __len__(self):
add = 1 if self.field.empty_label is not None else 0
add += 1 if self.field.null_label is not None else 0
return len(self.choices) + add
class ModelChoiceIterator(forms.models.ModelChoiceIterator):
# Extends the base ModelChoiceIterator to add in 'null' choice handling.
# This is a bit verbose since we have to insert the null choice after the
# empty choice, but before the remainder of the choices.
def __iter__(self):
iterable = super().__iter__()
if self.field.empty_label is not None:
yield next(iterable)
if self.field.null_label is not None:
yield (self.field.null_value, self.field.null_label)
yield from iterable
def __len__(self):
add = 1 if self.field.null_label is not None else 0
return super().__len__() + add
class ChoiceIteratorMixin:
def __init__(self, *args, **kwargs):
self.null_label = kwargs.pop('null_label', settings.NULL_CHOICE_LABEL)
self.null_value = kwargs.pop('null_value', settings.NULL_CHOICE_VALUE)
super().__init__(*args, **kwargs)
def _get_choices(self):
return super()._get_choices()
def _set_choices(self, value):
super()._set_choices(value)
value = self.iterator(self, self._choices)
self._choices = self.widget.choices = value
choices = property(_get_choices, _set_choices)
# Unlike their Model* counterparts, forms.ChoiceField and forms.MultipleChoiceField do not set empty_label
class ChoiceField(ChoiceIteratorMixin, forms.ChoiceField):
iterator = ChoiceIterator
def __init__(self, *args, **kwargs):
self.empty_label = kwargs.pop('empty_label', settings.EMPTY_CHOICE_LABEL)
super().__init__(*args, **kwargs)
class MultipleChoiceField(ChoiceIteratorMixin, forms.MultipleChoiceField):
iterator = ChoiceIterator
def __init__(self, *args, **kwargs):
self.empty_label = None
super().__init__(*args, **kwargs)
class ModelChoiceField(ChoiceIteratorMixin, forms.ModelChoiceField):
iterator = ModelChoiceIterator
def to_python(self, value):
# bypass the queryset value check
if self.null_label is not None and value == self.null_value:
return value
return super().to_python(value)
class ModelMultipleChoiceField(ChoiceIteratorMixin, forms.ModelMultipleChoiceField):
iterator = ModelChoiceIterator
def _check_values(self, value):
null = self.null_label is not None and value and self.null_value in value
if null: # remove the null value and any potential duplicates
value = [v for v in value if v != self.null_value]
result = list(super()._check_values(value))
result += [self.null_value] if null else []
return result
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