import { ModelBinder } from './modelbinder.class';
import { ModelState } from './modelstate.class';
import { Binding } from './binding.class';

/**
 * The binder is used to actually bind a validator to elements that are scoped to validation.
 * It's used internally only.
 * @ignore
 */
export class ValidatorBinding extends Binding {

  /**
   * The binder assignment that connects viewmodel properties to element attributes.
   * @param modelProperty The property of the viewmodel this binder binds to
   * @param handler The handler that handles the binding. For attribute binders this is 'default' {@link DefaultBindingHandler}
   * @param binderInstance The binder instance that provides access to the actual binder objects
   * @param el The element that the binder will assign the viewmodel to
   */
  constructor(
    modelProperty: string,
    private validationHandler: any,
    binderInstance: ModelBinder<any>,
    private validatorKey: string,
    el: HTMLElement
  ) {
    super(modelProperty, validationHandler, binderInstance, el);
    if (!validationHandler) {
      throw new Error('Missing validation handler');
    }
  }
  private property: string;
  /**
   * Define the binder. The property must be provided if the @see DefaultBindingHandler is used. This handler binds a value to any property of the
   * target element. Value and property are not typed, you can use any type for values. A typical scenario is the forwarding of validation information
   * as a boolean value to a sub-component using a sequence of model binders.
   * @param property An optional property, used to assign to a specific proeprty in multi-attribute binding
   */
  public bind(property?: string) {
    this.property = property;
    //const bindingHandler = this.binderInstance.handlers[this.handlerKey];
    this.validationHandler.bind && this.validationHandler.bind(this); // bind is optional
    this.binderInstance.subscribe(super.modelProperty, () => {
      this.validationHandler.react(this, this.property);
    });
  }
  public set value(value) {
    if (!this.binderInstance.state.validators[this.modelProperty]) {
      console.error(`Tried to add validation of type ${this.validatorKey} but no validation decorator was provided on property ${this.modelProperty}`);
    } else {
      this.binderInstance.state.validators[this.modelProperty].isValid[this.validatorKey] = value;
      this.validationHandler.react(this, this.property);
    }

  }
  public get value() {
    return this.binderInstance.state.validators[this.modelProperty].isValid[this.validatorKey];
  }
  public get validationProperty(): string {
    return super.modelProperty;
  }
  public get validationState(): ModelState<any> {
    return super.binderInstance.state;
  }
}