import { MaybeRefOrGetter } from 'vue';
import { BehaviorClass, GameEntity, GameEntityType } from '@skewedaspect/sage';
import { ObservedSimulation } from "../symbols.js";
type Bag = Record<string, unknown>;
/** The bag a view holds its state in: reactive for a template, and with no prototype the way its records are. */
export declare function createStateBag(): Bag;
/** Assigns what differs, adds what appeared, removes what vanished, and leaves everything else alone. */
export declare function syncBag(target: Bag, source: Readonly<Bag>): void;
/**
 * Answers with the entity that ID names in the simulation the engine currently holds, when it is of the class
 * asked for. A subclass is of that class, and a null ID names no entity
 * (design/ui.md#which-entity-a-view-holds).
 */
export declare function resolveEntity(simulation: ObservedSimulation | null | undefined, entityClass: GameEntityType, id: string | null): GameEntity | undefined;
/**
 * Answers with the entities carrying the tag, whatever their class, in the order the simulation holds them.
 * A behavior narrows that to the ones holding it (design/ui.md#gameentityview), and a null tag gathers
 * nothing (design/ui.md#which-entity-a-view-holds).
 */
export declare function resolveTagged(simulation: ObservedSimulation | null | undefined, tag: string | null, behaviorClass?: BehaviorClass): readonly GameEntity[];
/**
 * Builds the narrowing guard a view exposes. It resolves the entity on every call, so it answers from the
 * entity rather than from the view's copy of state, and a view whose entity has gone holds no behavior
 * (design/ui.md#gameentityview).
 */
export declare function buildHasBehavior(find: () => GameEntity | undefined): (behaviorClass: BehaviorClass) => boolean;
/**
 * Builds the operations a view exposes. Every call resolves the entity again, so a view whose entity has gone
 * throws rather than reaching the one it used to hold (design/ui.md#absence). One name answers with one
 * function for the view's life, so a template handing an operation to a child hands it the same function on
 * every render (design/ui.md#gameentityview).
 */
export declare function buildOps(id: MaybeRefOrGetter<string | null>, find: () => GameEntity | undefined): Record<string, unknown>;
export {};