"""
Defines `UserAdminModel` for registration of Misago `User` model in django
admin panel.

The model supposed to be used for interaction of third party django apps with
Misago `User` model, i.e. assignment to a `User` permissions or groups.

Registration call is placed in :mod:`misago.users.admin`.

Test for the model is placed in :mod:`misago.users.tests.test_djangoadmin_user`.
"""
from django import forms
from django.contrib import admin
from django.contrib.auth import get_user_model
from django.urls import reverse
from django.utils.html import format_html
from django.utils.translation import ugettext as _


# Misago user model
User = get_user_model()


class UserAdminForm(forms.ModelForm):
    """
    This form adds `edit_from_misago_link` pseudo-field, that renders
    itself like an html hyperlink to a user edit page in misago admin panel.

    This could be done with `User` edit template overwrite, but
    it is kind of overkill - overwrite the whole template just to add one
    button - isn't it?
    """
    #: pseudo-field
    edit_from_misago_link = forms.Field()

    def __init__(self, *args, **kwargs):
        # noinspection PyArgumentList
        super(UserAdminForm, self).__init__(*args, **kwargs)
        self.init_edit_from_misago_link_field()

    def init_edit_from_misago_link_field(self):
        """
        Init for the pseudo-field, and replace it's widget `render`.
        """
        field = self.fields['edit_from_misago_link']
        field.required = False
        field.label = ''
        field.widget.render = self.render_edit_from_misago_link

    # noinspection PyUnusedLocal
    def render_edit_from_misago_link(self, *args, **kwargs):
        """
        Composes an html hyperlink for the pseudo-field render.

        `*args` and `**kwargs` arguments need to mimic widget `render()`
        signature.

        :rtype: str
        """
        text = _('Edit this user in Misago admin panel')
        link_html_template = ('<a href="{}" target="blank">' + text + '</a>')
        link_url = reverse(
            viewname='misago:admin:users:accounts:edit',
            kwargs={'pk': self.instance.pk},
        )
        link_html = format_html(link_html_template, link_url)

        return link_html

    class Meta:
        model = User
        fields = ['edit_from_misago_link']


class UserAdminModel(admin.ModelAdmin):
    """
    Redeclare most of the model fields like read-only.
    Prevents new/delete actions (users should use misago admin panel for
    that).
    Replaces default form with custom `UserAdminForm`.
    """

    list_display = (
        'username',
        'email',
        'is_staff',
        'is_superuser',
    )
    search_fields = ('username', 'email')
    list_filter = ('groups', 'is_staff', 'is_superuser')

    form = UserAdminForm
    actions = None
    readonly_fields = (
        'username',
        'email',
        'rank',
        'last_login',
        'joined_on',
        'is_staff',
        'is_superuser',
    )
    fieldsets = (
        (
            _('Misago user data'),
            {'fields': (
                'username',
                'email',
                'rank',
                'last_login',
                'joined_on',
                'is_staff',
                'is_superuser',
                'edit_from_misago_link',
            )},
        ),
        (
            _('Edit permissions and groups'),
            {'fields': (
                'groups',
                'user_permissions',
            )},
        ),
    )

    def has_add_permission(self, request):
        return False

    def has_delete_permission(self, request, obj=None):
        return False