"""
HTML Widget classes
"""

from __future__ import unicode_literals

import copy
import datetime
import re
from itertools import chain

from django.conf import settings
from django.forms.utils import flatatt, to_current_timezone
from django.utils import datetime_safe, formats, six
from django.utils.datastructures import MultiValueDict
from django.utils.dates import MONTHS
from django.utils.encoding import (
    force_str, force_text, python_2_unicode_compatible,
)
from django.utils.formats import get_format
from django.utils.html import conditional_escape, format_html, html_safe
from django.utils.safestring import mark_safe
from django.utils.six.moves import range
from django.utils.six.moves.urllib.parse import urljoin
from django.utils.translation import ugettext_lazy

__all__ = (
    'Media', 'MediaDefiningClass', 'Widget', 'TextInput', 'NumberInput',
    'EmailInput', 'URLInput', 'PasswordInput', 'HiddenInput',
    'MultipleHiddenInput', 'FileInput', 'ClearableFileInput', 'Textarea',
    'DateInput', 'DateTimeInput', 'TimeInput', 'CheckboxInput', 'Select',
    'NullBooleanSelect', 'SelectMultiple', 'RadioSelect',
    'CheckboxSelectMultiple', 'MultiWidget', 'SplitDateTimeWidget',
    'SplitHiddenDateTimeWidget', 'SelectDateWidget',
)

MEDIA_TYPES = ('css', 'js')


@html_safe
@python_2_unicode_compatible
class Media(object):
    def __init__(self, media=None, **kwargs):
        if media:
            media_attrs = media.__dict__
        else:
            media_attrs = kwargs

        self._css = {}
        self._js = []

        for name in MEDIA_TYPES:
            getattr(self, 'add_' + name)(media_attrs.get(name))

    def __str__(self):
        return self.render()

    def render(self):
        return mark_safe('\n'.join(chain(*[getattr(self, 'render_' + name)() for name in MEDIA_TYPES])))

    def render_js(self):
        return [
            format_html(
                '<script type="text/javascript" src="{}"></script>',
                self.absolute_path(path)
            ) for path in self._js
        ]

    def render_css(self):
        # To keep rendering order consistent, we can't just iterate over items().
        # We need to sort the keys, and iterate over the sorted list.
        media = sorted(self._css.keys())
        return chain(*[[
            format_html(
                '<link href="{}" type="text/css" media="{}" rel="stylesheet" />',
                self.absolute_path(path), medium
            ) for path in self._css[medium]
        ] for medium in media])

    def absolute_path(self, path, prefix=None):
        if path.startswith(('http://', 'https://', '/')):
            return path
        if prefix is None:
            if settings.STATIC_URL is None:
                # backwards compatibility
                prefix = settings.MEDIA_URL
            else:
                prefix = settings.STATIC_URL
        return urljoin(prefix, path)

    def __getitem__(self, name):
        "Returns a Media object that only contains media of the given type"
        if name in MEDIA_TYPES:
            return Media(**{str(name): getattr(self, '_' + name)})
        raise KeyError('Unknown media type "%s"' % name)

    def add_js(self, data):
        if data:
            for path in data:
                if path not in self._js:
                    self._js.append(path)

    def add_css(self, data):
        if data:
            for medium, paths in data.items():
                for path in paths:
                    if not self._css.get(medium) or path not in self._css[medium]:
                        self._css.setdefault(medium, []).append(path)

    def __add__(self, other):
        combined = Media()
        for name in MEDIA_TYPES:
            getattr(combined, 'add_' + name)(getattr(self, '_' + name, None))
            getattr(combined, 'add_' + name)(getattr(other, '_' + name, None))
        return combined


def media_property(cls):
    def _media(self):
        # Get the media property of the superclass, if it exists
        sup_cls = super(cls, self)
        try:
            base = sup_cls.media
        except AttributeError:
            base = Media()

        # Get the media definition for this class
        definition = getattr(cls, 'Media', None)
        if definition:
            extend = getattr(definition, 'extend', True)
            if extend:
                if extend is True:
                    m = base
                else:
                    m = Media()
                    for medium in extend:
                        m = m + base[medium]
                return m + Media(definition)
            else:
                return Media(definition)
        else:
            return base
    return property(_media)


class MediaDefiningClass(type):
    """
    Metaclass for classes that can have media definitions.
    """
    def __new__(mcs, name, bases, attrs):
        new_class = (super(MediaDefiningClass, mcs)
            .__new__(mcs, name, bases, attrs))

        if 'media' not in attrs:
            new_class.media = media_property(new_class)

        return new_class


@html_safe
@python_2_unicode_compatible
class SubWidget(object):
    """
    Some widgets are made of multiple HTML elements -- namely, RadioSelect.
    This is a class that represents the "inner" HTML element of a widget.
    """
    def __init__(self, parent_widget, name, value, attrs, choices):
        self.parent_widget = parent_widget
        self.name, self.value = name, value
        self.attrs, self.choices = attrs, choices

    def __str__(self):
        args = [self.name, self.value, self.attrs]
        if self.choices:
            args.append(self.choices)
        return self.parent_widget.render(*args)


class Widget(six.with_metaclass(MediaDefiningClass)):
    needs_multipart_form = False  # Determines does this widget need multipart form
    is_localized = False
    is_required = False
    supports_microseconds = True

    def __init__(self, attrs=None):
        if attrs is not None:
            self.attrs = attrs.copy()
        else:
            self.attrs = {}

    def __deepcopy__(self, memo):
        obj = copy.copy(self)
        obj.attrs = self.attrs.copy()
        memo[id(self)] = obj
        return obj

    @property
    def is_hidden(self):
        return self.input_type == 'hidden' if hasattr(self, 'input_type') else False

    def subwidgets(self, name, value, attrs=None, choices=()):
        """
        Yields all "subwidgets" of this widget. Used only by RadioSelect to
        allow template access to individual <input type="radio"> buttons.

        Arguments are the same as for render().
        """
        yield SubWidget(self, name, value, attrs, choices)

    def render(self, name, value, attrs=None):
        """
        Returns this Widget rendered as HTML, as a Unicode string.

        The 'value' given is not guaranteed to be valid input, so subclass
        implementations should program defensively.
        """
        raise NotImplementedError('subclasses of Widget must provide a render() method')

    def build_attrs(self, extra_attrs=None, **kwargs):
        "Helper function for building an attribute dictionary."
        attrs = dict(self.attrs, **kwargs)
        if extra_attrs:
            attrs.update(extra_attrs)
        return attrs

    def value_from_datadict(self, data, files, name):
        """
        Given a dictionary of data and this widget's name, returns the value
        of this widget. Returns None if it's not provided.
        """
        return data.get(name)

    def id_for_label(self, id_):
        """
        Returns the HTML ID attribute of this Widget for use by a <label>,
        given the ID of the field. Returns None if no ID is available.

        This hook is necessary because some widgets have multiple HTML
        elements and, thus, multiple IDs. In that case, this method should
        return an ID value that corresponds to the first ID in the widget's
        tags.
        """
        return id_


class Input(Widget):
    """
    Base class for all <input> widgets (except type='checkbox' and
    type='radio', which are special).
    """
    input_type = None  # Subclasses must define this.

    def _format_value(self, value):
        if self.is_localized:
            return formats.localize_input(value)
        return value

    def render(self, name, value, attrs=None):
        if value is None:
            value = ''
        final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)
        if value != '':
            # Only add the 'value' attribute if a value is non-empty.
            final_attrs['value'] = force_text(self._format_value(value))
        return format_html('<input{} />', flatatt(final_attrs))


class TextInput(Input):
    input_type = 'text'

    def __init__(self, attrs=None):
        if attrs is not None:
            self.input_type = attrs.pop('type', self.input_type)
        super(TextInput, self).__init__(attrs)


class NumberInput(TextInput):
    input_type = 'number'


class EmailInput(TextInput):
    input_type = 'email'


class URLInput(TextInput):
    input_type = 'url'


class PasswordInput(TextInput):
    input_type = 'password'

    def __init__(self, attrs=None, render_value=False):
        super(PasswordInput, self).__init__(attrs)
        self.render_value = render_value

    def render(self, name, value, attrs=None):
        if not self.render_value:
            value = None
        return super(PasswordInput, self).render(name, value, attrs)


class HiddenInput(Input):
    input_type = 'hidden'


class MultipleHiddenInput(HiddenInput):
    """
    A widget that handles <input type="hidden"> for fields that have a list
    of values.
    """
    def __init__(self, attrs=None, choices=()):
        super(MultipleHiddenInput, self).__init__(attrs)
        # choices can be any iterable
        self.choices = choices

    def render(self, name, value, attrs=None, choices=()):
        if value is None:
            value = []
        final_attrs = self.build_attrs(attrs, type=self.input_type, name=name)
        id_ = final_attrs.get('id')
        inputs = []
        for i, v in enumerate(value):
            input_attrs = dict(value=force_text(v), **final_attrs)
            if id_:
                # An ID attribute was given. Add a numeric index as a suffix
                # so that the inputs don't all have the same ID attribute.
                input_attrs['id'] = '%s_%s' % (id_, i)
            inputs.append(format_html('<input{} />', flatatt(input_attrs)))
        return mark_safe('\n'.join(inputs))

    def value_from_datadict(self, data, files, name):
        if isinstance(data, MultiValueDict):
            return data.getlist(name)
        return data.get(name)


class FileInput(Input):
    input_type = 'file'
    needs_multipart_form = True

    def render(self, name, value, attrs=None):
        return super(FileInput, self).render(name, None, attrs=attrs)

    def value_from_datadict(self, data, files, name):
        "File widgets take data from FILES, not POST"