import { shallowEqual } from "shallow-equal-object";

export abstract class ValueObject<T> {
  protected readonly _value: T;

  protected constructor(value: T) {
    this._value = typeof value === "object" && value !== null ? Object.freeze(value) : value;

    Object.freeze(this);
  }

  equals(other: ValueObject<T>): boolean {
    if (!(other instanceof ValueObject)) {
      return false;
    }

    if (other._value === undefined || other._value === null) {
      return false;
    }

    return shallowEqual(this._value, other._value);
  }

  getValue(): T {
    return this._value;
  }

  isEmpty(): boolean {
    return this._value === null || this._value === undefined;
  }

  toString(): string {
    return this._value !== null && this._value !== undefined ? String(this._value) : "";
  }
}