import {ControlValueAccessor, FormControl, ValidationErrors, Validator} from '@angular/forms';

export abstract class CustomInputComponent implements ControlValueAccessor, Validator {
  protected value: any;
  protected parseError: boolean;
  private propagateChange: (_: any) => void = () => {};
  private propagateTouch: () => void = () => {};

  // set initial value
  public abstract writeValue(obj: any): void;

  // register function to notify on change
  public registerOnChange(fn: (_: any) => void): void {
    this.propagateChange = fn;
  }

  // register function to notify on touch
  public registerOnTouched(fn: () => void): void {
    this.propagateTouch = fn;
  }

  // validates the form, returns null when valid else the validation object
  public abstract validate(c: FormControl): ValidationErrors;

  // on change
  protected change(): void {
    this.propagateChange(this.value);
  }

  // on touch
  protected blur(): void {
    this.propagateTouch();
  }
}