import { GameEntity } from "../core/GameEntity";

/**
 * Base class for representing a goal evaluator in context of Goal-driven agent design.
 */
export class GoalEvaluator<T extends GameEntity> {
    /**
     * Can be used to adjust the preferences of agents. When the desirability score
     * for a goal has been evaluated, it is multiplied by this value.
     * @default 1
     */
    characterBias: number;

    /**
     * Constructs a new goal evaluator.
     *
     * @param characterBias - Can be used to adjust the preferences of agents.
     */
    constructor(characterBias?: number);

    /**
     * Calculates the desirability. It's a score between 0 and 1 representing the desirability
     * of a goal. This goal is considered as a top level strategy of the agent like *Explore* or
     * *AttackTarget*. Must be implemented by all concrete goal evaluators.
     *
     * @param owner - The owner of this goal evaluator.
     * @return The desirability.
     */
    calculateDesirability(owner: T): number;

    /**
     * Executed if this goal evaluator produces the highest desirability. Must be implemented
     * by all concrete goal evaluators.
     *
     * @param owner - The owner of this goal evaluator.
     */
    setGoal(owner: T): void;

    /**
     * Transforms this instance into a JSON object.
     *
     * @return The JSON object.
     */
    toJSON(): { [s: string]: any };

    /**
     * Restores this instance from the given JSON object.
     *
     * @param json - The JSON object.
     */
    fromJSON(json: { [s: string]: any }): this;
}