import { Directive, forwardRef } from '@angular/core';
import {Validators, FormControl} from "@angular/forms";
import { NG_VALUE_ACCESSOR, ControlValueAccessor, NG_VALIDATORS } from "@angular/forms";

@Directive( {
  selector: "input[type=file]",
  host: {
    "(change)": "onChange($event.target.files)",
    "(blur)": "onTouched()"
  },
  providers: [
    { provide: NG_VALIDATORS, useExisting: forwardRef( () => FileValidatorDirective ), multi: true },
    { provide: NG_VALUE_ACCESSOR, useExisting: forwardRef( () => FileValidatorDirective ), multi: true }
  ]
} )

export class FileValidatorDirective implements ControlValueAccessor, Validators {
  onChange = () => {

  };

  onTouched = () => {
  };

  writeValue( value ) {
    debugger;
  }

  registerOnChange( fn: any ) {
    debugger;
    this.onChange = fn;
  }

  registerOnTouched( fn: any ) {
    this.onTouched = fn;
  }

  validate( c: FormControl ): {[key: string]: any} {
    debugger;
    return c.value == null || c.value.length == 0 ? { "required": true } : null;
  }
}