from django import forms
from django.conf import settings
from django.utils.translation import gettext as _
from django.utils.translation import ngettext

from wagtail.admin import widgets
from wagtail.models import Page, PageViewRestriction

from .models import WagtailAdminModelForm
from .view_restrictions import BaseViewRestrictionForm


class CopyForm(forms.Form):
    def __init__(self, *args, **kwargs):
        # CopyPage must be passed a 'page' kwarg indicating the page to be copied
        self.page = kwargs.pop("page")
        self.user = kwargs.pop("user", None)
        can_publish = kwargs.pop("can_publish")
        super().__init__(*args, **kwargs)
        self.fields["new_title"] = forms.CharField(
            initial=self.page.title, label=_("New title")
        )
        allow_unicode = getattr(settings, "WAGTAIL_ALLOW_UNICODE_SLUGS", True)
        self.fields["new_slug"] = forms.SlugField(
            initial=self.page.slug,
            label=_("New slug"),
            allow_unicode=allow_unicode,
            widget=widgets.SlugInput,
        )
        self.fields["new_parent_page"] = forms.ModelChoiceField(
            initial=self.page.get_parent(),
            queryset=Page.objects.all(),
            widget=widgets.AdminPageChooser(can_choose_root=True, user_perms="copy_to"),
            label=_("New parent page"),
            help_text=_("This copy will be a child of this given parent page."),
        )
        pages_to_copy = self.page.get_descendants(inclusive=True)
        subpage_count = pages_to_copy.count() - 1
        if subpage_count > 0:
            self.fields["copy_subpages"] = forms.BooleanField(
                required=False,
                initial=True,
                label=_("Copy subpages"),
                help_text=ngettext(
                    "This will copy %(count)s subpage.",
                    "This will copy %(count)s subpages.",
                    subpage_count,
                )
                % {"count": subpage_count},
            )

        if can_publish:
            pages_to_publish_count = pages_to_copy.live().count()
            if pages_to_publish_count > 0:
                # In the specific case that there are no subpages, customise the field label and help text
                if subpage_count == 0:
                    label = _("Publish copied page")
                    help_text = _(
                        "This page is live. Would you like to publish its copy as well?"
                    )
                else:
                    label = _("Publish copies")
                    help_text = ngettext(
                        "%(count)s of the pages being copied is live. Would you like to publish its copy?",
                        "%(count)s of the pages being copied are live. Would you like to publish their copies?",
                        pages_to_publish_count,
                    ) % {"count": pages_to_publish_count}

                self.fields["publish_copies"] = forms.BooleanField(
                    required=False, initial=False, label=label, help_text=help_text
                )

            # Note that only users who can publish in the new parent page can create an alias.
            # This is because alias pages must always match their original page's state.
            self.fields["alias"] = forms.BooleanField(
                required=False,
                initial=False,
                label=_("Alias"),
                help_text=_("Keep the new pages updated with future changes"),
            )

    def clean(self):
        cleaned_data = super().clean()

        # Make sure the slug isn't already in use
        slug = cleaned_data.get("new_slug")

        # New parent page given in form or parent of source, if parent_page is empty
        parent_page = cleaned_data.get("new_parent_page") or self.page.get_parent()

        # check if user is allowed to create a page at given location.
        if not parent_page.permissions_for_user(self.user).can_add_subpage():
            self._errors["new_parent_page"] = self.error_class(
                [
                    _('You do not have permission to copy to page "%(page_title)s"')
                    % {
                        "page_title": parent_page.specific_deferred.get_admin_display_title()
                    }
                ]
            )

        # Count the pages with the same slug within the context of our copy's parent page
        if slug and parent_page.get_children().filter(slug=slug).count():
            self._errors["new_slug"] = self.error_class(
                [
                    _(
                        'This slug is already in use within the context of its parent page "%(parent_page_title)s"'
                    )
                    % {"parent_page_title": parent_page}
                ]
            )
            # The slug is no longer valid, hence remove it from cleaned_data
            del cleaned_data["new_slug"]

        # Don't allow recursive copies into self
        if cleaned_data.get("copy_subpages") and (
            self.page == parent_page or parent_page.is_descendant_of(self.page)
        ):
            self._errors["new_parent_page"] = self.error_class(
                [_("You cannot copy a page into itself when copying subpages")]
            )

        return cleaned_data


class PageViewRestrictionForm(BaseViewRestrictionForm):
    def __init__(self, *args, **kwargs):
        # get the list of private page options from the page
        private_page_options = kwargs.pop("private_page_options", [])

        super().__init__(*args, **kwargs)

        if not getattr(settings, "WAGTAIL_PRIVATE_PAGE_OPTIONS", {}).get(
            "SHARED_PASSWORD", True
        ):
            self.fields["restriction_type"].choices = [
                choice
                for choice in PageViewRestriction.RESTRICTION_CHOICES
                if choice[0] != PageViewRestriction.PASSWORD
            ]
            del self.fields["password"]
        # Remove the fields that are not allowed for the page
        self.fields["restriction_type"].choices = [
            choice
            for choice in self.fields["restriction_type"].choices
            if choice[0] in private_page_options
            or choice[0] == PageViewRestriction.NONE
        ]

    class Meta:
        model = PageViewRestriction
        fields = ("restriction_type", "password", "groups")


class WagtailAdminPageForm(WagtailAdminModelForm):
    comment_notifications = forms.BooleanField(
        widget=forms.CheckboxInput(), required=False
    )

    def __init__(
        self,
        data=None,
        files=None,
        parent_page=None,
        subscription=None,
        *args,
        **kwargs,
    ):
        self.subscription = subscription

        initial = kwargs.pop("initial", {})
        if self.subscription:
            initial["comment_notifications"] = subscription.comment_notifications

        super().__init__(data, files, *args, initial=initial, **kwargs)

        self.parent_page = parent_page

        if not self.show_comments_toggle:
            del self.fields["comment_notifications"]

    @property
    def show_comments_toggle(self):
        return "comments" in self.__class__.formsets

    def save(self, commit=True):
        # Save comment notifications updates to PageSubscription
        if self.show_comments_toggle and self.subscription:
            self.subscription.comment_notifications = self.cleaned_data[
                "comment_notifications"
            ]
            if commit:
                self.subscription.save()

        return super().save(commit=commit)

    def is_valid(self):
        comments = self.formsets.get("comments")
        # Remove the comments formset if the management form is invalid
        if comments and not comments.management_form.is_valid():
            del self.formsets["comments"]
        return super().is_valid()

    def clean(self):
        cleaned_data = super().clean()
        if "slug" in self.cleaned_data:
            page_slug = cleaned_data["slug"]
            if not Page._slug_is_available(page_slug, self.parent_page, self.instance):
                self.add_error(
                    "slug",
                    forms.ValidationError(
                        _(
                            "The slug '%(page_slug)s' is already in use within the parent page"
                        )
                        % {"page_slug": page_slug}
                    ),
                )

        return cleaned_data


class MoveForm(forms.Form):
    def __init__(self, *args, **kwargs):
        self.page_to_move = kwargs.pop("page_to_move")
        self.target_parent_models = kwargs.pop("target_parent_models")

        super().__init__(*args, **kwargs)

        self.fields["new_parent_page"] = forms.ModelChoiceField(
            initial=self.page_to_move.get_parent(),
            queryset=Page.objects.all(),
            widget=widgets.AdminPageMoveChooser(
                can_choose_root=True,
                user_perms="move_to",
                target_models=self.target_parent_models,
                pages_to_move=[self.page_to_move.pk],
            ),
            label=_("New parent page"),
            help_text=_("Select a new parent for this page."),
        )


class ParentChooserForm(forms.Form):
    def __init__(self, child_page_type, user, *args, **kwargs):
        self.child_page_type = child_page_type
        self.user = user
        super().__init__(*args, **kwargs)
        self.fields["parent_page"] = forms.ModelChoiceField(
            queryset=Page.objects.all(),
            widget=widgets.AdminPageChooser(
                target_models=self.child_page_type.allowed_parent_page_models(),
                can_choose_root=True,
                user_perms="add_subpage",
            ),
            label=_("Parent page"),
            help_text=_("The new page will be a child of this given parent page."),
        )

    def clean_parent_page(self):
        parent_page = self.cleaned_data["parent_page"].specific_deferred
        if not parent_page.permissions_for_user(self.user).can_add_subpage():
            raise forms.ValidationError(
                _('You do not have permission to create a page under "%(page_title)s".')
                % {"page_title": parent_page.get_admin_display_title()}
            )
        if not self.child_page_type.can_create_at(parent_page):
            raise forms.ValidationError(
                _(
                    'You cannot create a page of type "%(page_type)s" under "%(page_title)s".'
                )
                % {
                    "page_type": self.child_page_type.get_verbose_name(),
                    "page_title": parent_page.get_admin_display_title(),
                }
            )
        return parent_page
