import { PermissionCheckerForAttribute } from "@server/meta/fd-meta-core/attributes/permission-checker-for-attribute";
import { ResourcePermissionChecker } from "@server/meta/fd-meta-core/auth/permissions/resource-permission-checker";
import { singleOrDefault } from "@server/fd/fd-toolbox/collections/single-warnings";

interface LifetimeScope {
    resolve: <T>(type: new () => T) => T[];
}

let permissionCheckers: ResourcePermissionChecker[] | null = null;

function getPermissionCheckers(lifetimeScope: LifetimeScope): ResourcePermissionChecker[] {
    if (permissionCheckers === null) {
        permissionCheckers = lifetimeScope.resolve(ResourcePermissionChecker);
    }
    return permissionCheckers;
}

export function getPermissionChecker(resourceName: string, lifetimeScope: LifetimeScope) {
    const checkers = getPermissionCheckers(lifetimeScope);

    const matchingCheckers = checkers.filter((checker) => {
        const attr = Reflect.getMetadata(
            "PermissionCheckerFor",
            checker.constructor,
        ) as PermissionCheckerForAttribute;
        return attr?.ResourceName === resourceName;
    });

    return singleOrDefault(matchingCheckers);
}