from typing import Any

from django.contrib import admin
from django.contrib.admin.views.main import ChangeList
from django.db import models
from django.db.models import QuerySet
from django.http import HttpRequest
from django.urls import reverse

from .models import ExternalReservation, Reservation, Resource, UserReservation


@admin.register(Resource)
class ResourceAdmin(admin.ModelAdmin):
    list_display = ["name", "parent", "min_length", "max_length"]
    list_filter = ["parent"]
    search_fields = ["name"]
    show_facets = admin.ShowFacets.ALWAYS


class ReservationTypeFilter(admin.SimpleListFilter):
    """Filter by subclass"""

    title = "Reservation Type"
    parameter_name = "type"

    # TODO: this could be automatic
    _subtypes = {
        "eventmeetingtime": "Event Meeting Time",
        "userreservation": "User Reservation",
        "externalreservation": "External Reservation",
    }

    def lookups(
        self, request: HttpRequest, model_admin: admin.ModelAdmin
    ) -> list[tuple[str, str]]:
        return [
            ("generic", "Generic Reservation"),
        ] + list(self._subtypes.items())

    def queryset(self, request: HttpRequest, queryset: QuerySet) -> QuerySet:
        if self.value() in self._subtypes:
            return queryset.filter(**{f"{self.value()}__isnull": False})
        elif self.value() == "generic":
            return queryset.filter(
                **{f"{subtype}__isnull": True for subtype in self._subtypes}
            )
        else:
            return queryset


class SubclassChangeList(ChangeList):
    def url_for_result(self, result: models.Model) -> str:
        opts = type(result)._meta
        return reverse(
            f"admin:{opts.app_label}_{opts.model_name}_change",
            args=(result.pk,),
            current_app=self.model_admin.admin_site.name,
        )


@admin.register(Reservation)
class ReservationAdmin(admin.ModelAdmin):
    list_display = ["_title", "_resources", "start", "end"]
    readonly_fields = ["google_calendar_event_id"]
    list_filter = ["resources", ReservationTypeFilter]
    show_facets = admin.ShowFacets.ALWAYS
    date_hierarchy = "start"

    def get_queryset(self, request):
        return (
            super()
            .get_queryset(request)
            .select_related("eventmeetingtime__event")
            .prefetch_related("resources")
            .select_subclasses()
        )

    @admin.display()
    def _title(self, obj: Reservation):
        return obj.get_title()

    @admin.display()
    def _resources(self, obj: Reservation):
        return list(obj.resources.all()) or None

    def get_changelist(self, request: HttpRequest, **kwargs: Any) -> type[ChangeList]:
        return SubclassChangeList


@admin.register(UserReservation)
class UserReservationAdmin(admin.ModelAdmin):
    def has_module_permission(self, request: HttpRequest) -> bool:
        return False


@admin.register(ExternalReservation)
class ExternalReservationAdmin(admin.ModelAdmin):
    def has_module_permission(self, request: HttpRequest) -> bool:
        return False