from django.conf import settings
from django.contrib import admin
from django.contrib.auth.admin import UserAdmin
from django_object_actions import DjangoObjectActions, action

from .models import CustomUser

# Must match loadtest/locustfile.py's own defaults (LOAD_TEST_USER_COUNT,
# LOAD_TEST_USER_PREFIX, LOAD_TEST_PASSWORD) - see that file for what these
# accounts are for and how they're used.
LOAD_TEST_USER_COUNT = 500
LOAD_TEST_USER_PREFIX = "loadtest"
LOAD_TEST_PASSWORD = "loadtest-only-password"


@admin.register(CustomUser)
class CustomUserAdmin(DjangoObjectActions, UserAdmin):
    """Admin interface for CustomUser."""

    # Add custom fields to the user admin
    fieldsets = UserAdmin.fieldsets + (
        (
            "CAS Information",
            {
                "fields": ("cas_user_id", "cas_groups", "cas_attributes"),
            },
        ),
    )

    # Add custom fields to the list display
    list_display = UserAdmin.list_display + ("cas_user_id", "get_cas_groups_display")

    # Add search fields
    search_fields = UserAdmin.search_fields + ("cas_user_id",)

    # Add filters
    list_filter = UserAdmin.list_filter + ("cas_groups",)

    # Make CAS fields readonly in admin
    readonly_fields = ("cas_user_id", "cas_groups", "cas_attributes")

    changelist_actions = ("create_load_test_users",)

    def get_cas_groups_display(self, obj):
        """Display CAS groups in admin list."""
        return obj.get_cas_groups_display()

    get_cas_groups_display.short_description = "CAS Groups"

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

    def get_changelist_actions(self, request):
        # Second layer of the same guard rail as the login endpoint itself
        # (see testing_auth_views.py): the button doesn't even show up
        # unless this deployment opted into load testing.
        if not settings.LOAD_TEST_LOGIN_ENABLED:
            return []
        return super().get_changelist_actions(request)

    @action(
        label="Create load test users",
        description=(
            "Create/reset the local loadtestN accounts used by "
            "loadtest/locustfile.py - authenticates via ModelBackend, "
            "never the real CAS server"
        ),
    )
    def create_load_test_users(self, request, _queryset):
        created = 0
        for i in range(LOAD_TEST_USER_COUNT):
            username = f"{LOAD_TEST_USER_PREFIX}{i}"
            user, was_created = CustomUser.objects.get_or_create(username=username)
            user.set_password(LOAD_TEST_PASSWORD)
            user.save()
            created += was_created

        self.message_user(
            request,
            f"{created} created, {LOAD_TEST_USER_COUNT - created} already existed "
            f"(password reset on all {LOAD_TEST_USER_COUNT}).",
        )