# Generated by Django 4.2.1 on 2023-06-14 16:23

from django.contrib.auth.management import create_permissions
from django.db import migrations, models
from django.db.models.functions import Concat, Length, Substr


def add_permissions(apps, schema_editor):
    # Ensure all the new permissions in Page.Meta.permissions are created
    app_config = apps.get_app_config("wagtailcore")
    app_config.models_module = True
    create_permissions(app_config, verbosity=0)
    app_config.models_module = None


def populate_grouppagepermission_permission(apps, schema_editor):
    ContentType = apps.get_model("contenttypes.ContentType")
    Permission = apps.get_model("auth.Permission")
    GroupPagePermission = apps.get_model("wagtailcore.GroupPagePermission")

    page_type = ContentType.objects.get_by_natural_key("wagtailcore", "page")

    # Normalise permission_type="edit" to permission_type="change"
    # and backfill permission from permission_type
    GroupPagePermission.objects.filter(
        models.Q(permission__isnull=True) | models.Q(permission_type="edit")
    ).annotate(
        normalised_permission_type=models.Case(
            models.When(permission_type="edit", then=models.Value("change")),
            default=models.F("permission_type"),
        )
    ).update(
        permission=Permission.objects.filter(
            content_type=page_type,
            codename=Concat(
                models.OuterRef("normalised_permission_type"),
                models.Value("_page"),
            ),
        ).values_list("pk", flat=True)[:1],
        permission_type=models.F("normalised_permission_type"),
    )


def revert_grouppagepermission_permission(apps, schema_editor):
    GroupPagePermission = apps.get_model("wagtailcore.GroupPagePermission")
    Permission = apps.get_model("auth.Permission")

    permission_type = (
        Permission.objects.filter(pk=models.OuterRef("permission"))
        .annotate(
            action=Substr(
                models.F("codename"),
                # Substr is 1-indexed
                1,
                # Length - 5 to remove "_page" suffix
                Length(models.F("codename")) - 5,
            )
        )
        .annotate(
            # Replace "change" with "edit" to match old permission_type
            permission_type=models.Case(
                models.When(action="change", then=models.Value("edit")),
                default=models.F("action"),
            )
        )
        .values("permission_type")[:1]
    )

    # Backfill permission_type from permission foreign key and clear the foreign key
    GroupPagePermission.objects.all().update(
        permission_type=permission_type,
        permission=None,
    )


class Migration(migrations.Migration):

    dependencies = [
        ("wagtailcore", "0085_add_grouppagepermission_permission"),
    ]

    operations = [
        migrations.RunPython(add_permissions, migrations.operations.RunPython.noop),
        migrations.RunPython(
            populate_grouppagepermission_permission,
            revert_grouppagepermission_permission,
        ),
    ]