"""
Form Widget classes specific to the Django admin site.
"""
from __future__ import unicode_literals

import copy

from django import forms
from django.db.models.deletion import CASCADE
from django.core.exceptions import ValidationError
from django.core.validators import URLValidator
from django.forms.utils import flatatt
from django.forms.widgets import RadioFieldRenderer
from django.template.loader import render_to_string
from django.urls import reverse
from django.urls.exceptions import NoReverseMatch
from django.utils import six
from django.utils.http import urlencode
from django.utils.encoding import force_text
from django.utils.html import format_html, format_html_join, smart_urlquote
from django.utils.safestring import mark_safe
from django.utils.text import Truncator
from django.utils.translation import ugettext as _


class FilteredSelectMultiple(forms.SelectMultiple):
    """
    A SelectMultiple with a JavaScript filter interface.

    Note that the resulting JavaScript assumes that the jsi18n
    catalog has been loaded in the page
    """
    @property
    def media(self):
        js = ["core.js", "SelectBox.js", "SelectFilter2.js"]
        return forms.Media(js=["admin/js/%s" % path for path in js])

    def __init__(self, verbose_name, is_stacked, attrs=None, choices=()):
        self.verbose_name = verbose_name
        self.is_stacked = is_stacked
        super(FilteredSelectMultiple, self).__init__(attrs, choices)

    def render(self, name, value, attrs=None):
        if attrs is None:
            attrs = {}
        attrs['class'] = 'selectfilter'
        if self.is_stacked:
            attrs['class'] += 'stacked'

        attrs['data-field-name'] = self.verbose_name
        attrs['data-is-stacked'] = int(self.is_stacked)
        output = super(FilteredSelectMultiple, self).render(name, value, attrs)
        return mark_safe(output)


class AdminDateWidget(forms.DateInput):
    @property
    def media(self):
        js = ["calendar.js", "admin/DateTimeShortcuts.js"]
        return forms.Media(js=["admin/js/%s" % path for path in js])

    def __init__(self, attrs=None, format=None):
        final_attrs = {'class': 'vDateField', 'size': '10'}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminDateWidget, self).__init__(attrs=final_attrs, format=format)


class AdminTimeWidget(forms.TimeInput):
    @property
    def media(self):
        js = ["calendar.js", "admin/DateTimeShortcuts.js"]
        return forms.Media(js=["admin/js/%s" % path for path in js])

    def __init__(self, attrs=None, format=None):
        final_attrs = {'class': 'vTimeField', 'size': '8'}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminTimeWidget, self).__init__(attrs=final_attrs, format=format)


class AdminSplitDateTime(forms.SplitDateTimeWidget):
    """
    A SplitDateTime Widget that has some admin-specific styling.
    """
    def __init__(self, attrs=None):
        widgets = [AdminDateWidget, AdminTimeWidget]
        # Note that we're calling MultiWidget, not SplitDateTimeWidget, because
        # we want to define widgets.
        forms.MultiWidget.__init__(self, widgets, attrs)

    def format_output(self, rendered_widgets):
        return format_html('<p class="datetime">{} {}<br />{} {}</p>',
                           _('Date:'), rendered_widgets[0],
                           _('Time:'), rendered_widgets[1])


class AdminRadioFieldRenderer(RadioFieldRenderer):
    def render(self):
        """Outputs a <ul> for this set of radio fields."""
        return format_html('<ul{}>\n{}\n</ul>',
                           flatatt(self.attrs),
                           format_html_join('\n', '<li>{}</li>',
                                            ((force_text(w),) for w in self)))


class AdminRadioSelect(forms.RadioSelect):
    renderer = AdminRadioFieldRenderer


class AdminFileWidget(forms.ClearableFileInput):
    template_with_initial = (
        '<p class="file-upload">%s</p>' % forms.ClearableFileInput.template_with_initial
    )
    template_with_clear = (
        '<span class="clearable-file-input">%s</span>' % forms.ClearableFileInput.template_with_clear
    )


def url_params_from_lookup_dict(lookups):
    """
    Converts the type of lookups specified in a ForeignKey limit_choices_to
    attribute to a dictionary of query parameters
    """
    params = {}
    if lookups and hasattr(lookups, 'items'):
        items = []
        for k, v in lookups.items():
            if callable(v):
                v = v()
            if isinstance(v, (tuple, list)):
                v = ','.join(str(x) for x in v)
            elif isinstance(v, bool):
                v = ('0', '1')[v]
            else:
                v = six.text_type(v)
            items.append((k, v))
        params.update(dict(items))
    return params


class ForeignKeyRawIdWidget(forms.TextInput):
    """
    A Widget for displaying ForeignKeys in the "raw_id" interface rather than
    in a <select> box.
    """
    def __init__(self, rel, admin_site, attrs=None, using=None):
        self.rel = rel
        self.admin_site = admin_site
        self.db = using
        super(ForeignKeyRawIdWidget, self).__init__(attrs)

    def render(self, name, value, attrs=None):
        rel_to = self.rel.model
        if attrs is None:
            attrs = {}
        extra = []
        if rel_to in self.admin_site._registry:
            # The related object is registered with the same AdminSite
            related_url = reverse(
                'admin:%s_%s_changelist' % (
                    rel_to._meta.app_label,
                    rel_to._meta.model_name,
                ),
                current_app=self.admin_site.name,
            )

            params = self.url_parameters()
            if params:
                url = '?' + urlencode(params)
            else:
                url = ''
            if "class" not in attrs:
                attrs['class'] = 'vForeignKeyRawIdAdminField'  # The JavaScript code looks for this hook.
            # TODO: "lookup_id_" is hard-coded here. This should instead use
            # the correct API to determine the ID dynamically.
            extra.append(
                '<a href="%s%s" class="related-lookup" id="lookup_id_%s" title="%s"></a>'
                % (related_url, url, name, _('Lookup'))
            )
        output = [super(ForeignKeyRawIdWidget, self).render(name, value, attrs)] + extra
        if value:
            output.append(self.label_for_value(value))
        return mark_safe(''.join(output))

    def base_url_parameters(self):
        limit_choices_to = self.rel.limit_choices_to
        if callable(limit_choices_to):
            limit_choices_to = limit_choices_to()
        return url_params_from_lookup_dict(limit_choices_to)

    def url_parameters(self):
        from django.contrib.admin.views.main import TO_FIELD_VAR
        params = self.base_url_parameters()
        params.update({TO_FIELD_VAR: self.rel.get_related_field().name})
        return params

    def label_for_value(self, value):
        key = self.rel.get_related_field().name
        try:
            obj = self.rel.model._default_manager.using(self.db).get(**{key: value})
        except (ValueError, self.rel.model.DoesNotExist):
            return ''

        label = '&nbsp;<strong>{}</strong>'
        text = Truncator(obj).words(14, truncate='...')
        try:
            change_url = reverse(
                '%s:%s_%s_change' % (
                    self.admin_site.name,
                    obj._meta.app_label,
                    obj._meta.object_name.lower(),
                ),
                args=(obj.pk,)
            )
        except NoReverseMatch:
            pass  # Admin not registered for target model.
        else:
            text = format_html('<a href="{}">{}</a>', change_url, text)

        return format_html(label, text)


class ManyToManyRawIdWidget(ForeignKeyRawIdWidget):
    """
    A Widget for displaying ManyToMany ids in the "raw_id" interface rather than
    in a <select multiple> box.
    """
    def render(self, name, value, attrs=None):
        if attrs is None:
            attrs = {}
        if self.rel.model in self.admin_site._registry:
            # The related object is registered with the same AdminSite
            attrs['class'] = 'vManyToManyRawIdAdminField'
        if value:
            value = ','.join(force_text(v) for v in value)
        else:
            value = ''
        return super(ManyToManyRawIdWidget, self).render(name, value, attrs)

    def url_parameters(self):
        return self.base_url_parameters()

    def label_for_value(self, value):
        return ''

    def value_from_datadict(self, data, files, name):
        value = data.get(name)
        if value:
            return value.split(',')


class RelatedFieldWidgetWrapper(forms.Widget):
    """
    This class is a wrapper to a given widget to add the add icon for the
    admin interface.
    """
    template = 'admin/related_widget_wrapper.html'

    def __init__(self, widget, rel, admin_site, can_add_related=None,
                 can_change_related=False, can_delete_related=False):
        self.needs_multipart_form = widget.needs_multipart_form
        self.attrs = widget.attrs
        self.choices = widget.choices
        self.widget = widget
        self.rel = rel
        # Backwards compatible check for whether a user can add related
        # objects.
        if can_add_related is None:
            can_add_related = rel.model in admin_site._registry
        self.can_add_related = can_add_related
        # XXX: The UX does not support multiple selected values.
        multiple = getattr(widget, 'allow_multiple_selected', False)
        self.can_change_related = not multiple and can_change_related
        # XXX: The deletion UX can be confusing when dealing with cascading deletion.
        cascade = getattr(rel, 'on_delete', None) is CASCADE
        self.can_delete_related = not multiple and not cascade and can_delete_related
        # so we can check if the related object is registered with this AdminSite
        self.admin_site = admin_site

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

    @property
    def is_hidden(self):
        return self.widget.is_hidden

    @property
    def media(self):
        return self.widget.media

    def get_related_url(self, info, action, *args):
        return reverse("admin:%s_%s_%s" % (info + (action,)),
                       current_app=self.admin_site.name, args=args)

    def render(self, name, value, *args, **kwargs):
        from django.contrib.admin.views.main import IS_POPUP_VAR, TO_FIELD_VAR
        rel_opts = self.rel.model._meta
        info = (rel_opts.app_label, rel_opts.model_name)
        self.widget.choices = self.choices
        url_params = '&'.join("%s=%s" % param for param in [
            (TO_FIELD_VAR, self.rel.get_related_field().name),
            (IS_POPUP_VAR, 1),
        ])
        context = {
            'widget': self.widget.render(name, value, *args, **kwargs),
            'name': name,
            'url_params': url_params,
            'model': rel_opts.verbose_name,
        }
        if self.can_change_related:
            change_related_template_url = self.get_related_url(info, 'change', '__fk__')
            context.update(
                can_change_related=True,
                change_related_template_url=change_related_template_url,
            )
        if self.can_add_related:
            add_related_url = self.get_related_url(info, 'add')
            context.update(
                can_add_related=True,
                add_related_url=add_related_url,
            )
        if self.can_delete_related:
            delete_related_template_url = self.get_related_url(info, 'delete', '__fk__')
            context.update(
                can_delete_related=True,
                delete_related_template_url=delete_related_template_url,
            )
        return mark_safe(render_to_string(self.template, context))

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

    def value_from_datadict(self, data, files, name):
        return self.widget.value_from_datadict(data, files, name)

    def value_omitted_from_data(self, data, files, name):
        return self.widget.value_omitted_from_data(data, files, name)

    def id_for_label(self, id_):
        return self.widget.id_for_label(id_)


class AdminTextareaWidget(forms.Textarea):
    def __init__(self, attrs=None):
        final_attrs = {'class': 'vLargeTextField'}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminTextareaWidget, self).__init__(attrs=final_attrs)


class AdminTextInputWidget(forms.TextInput):
    def __init__(self, attrs=None):
        final_attrs = {'class': 'vTextField'}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminTextInputWidget, self).__init__(attrs=final_attrs)


class AdminEmailInputWidget(forms.EmailInput):
    def __init__(self, attrs=None):
        final_attrs = {'class': 'vTextField'}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminEmailInputWidget, self).__init__(attrs=final_attrs)


class AdminURLFieldWidget(forms.URLInput):
    def __init__(self, attrs=None, validator_class=URLValidator):
        final_attrs = {'class': 'vURLField'}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminURLFieldWidget, self).__init__(attrs=final_attrs)
        self.validator = validator_class()

    def render(self, name, value, attrs=None):
        html = super(AdminURLFieldWidget, self).render(name, value, attrs)
        try:
            self.validator(value if value else '')
        except ValidationError:
            pass
        else:
            value = force_text(self.format_value(value))
            final_attrs = {'href': smart_urlquote(value)}
            html = format_html(
                '<p class="url">{} <a{}>{}</a><br />{} {}</p>',
                _('Currently:'), flatatt(final_attrs), value,
                _('Change:'), html
            )
        return html


class AdminIntegerFieldWidget(forms.TextInput):
    class_name = 'vIntegerField'

    def __init__(self, attrs=None):
        final_attrs = {'class': self.class_name}
        if attrs is not None:
            final_attrs.update(attrs)
        super(AdminIntegerFieldWidget, self).__init__(attrs=final_attrs)


class AdminBigIntegerFieldWidget(AdminIntegerFieldWidget):
    class_name = 'vBigIntegerField'