onDateInputChange(event: any): void {
    const raw: any = (event && (event.currentTarget?.value
      ?? event.target?.value
      ?? (typeof event === 'string' ? event : undefined)))
      ?? '';

    const val: string = String(raw).trim();

    const ctrl: AbstractControl = this.fields && this.fields['proxy_date'];
    const applyInvalid: () => void = (): void => {
      if (!ctrl) { return; }
      ctrl.setValue(null, { emitEvent: false });
      ctrl.updateValueAndValidity({ onlySelf: true, emitEvent: false });
      const errs: { [key: string]: any } = { ...(ctrl.errors || {}) };
      errs['invalidDate'] = true;
      ctrl.setErrors(errs);
      ctrl.markAsTouched();
    }

    const removeInvalidFlagIfPresent: () => void = (): void => {
      if (!ctrl) { return; }
      const errs = { ...(ctrl.errors || {}) };
      if (errs['invalidDate']) { delete errs['invalidDate']; }
      ctrl.setErrors(Object.keys(errs).length ? errs : null);
    };

    if (!val) { applyInvalid(); return; }
    const match: RegExpMatchArray|null = val.match(/^\s*(\d{1,2})\s*[.\-\/]\s*(\d{1,2})\s*[.\-\/]\s*(\d{4})\s*$/);
    if (!match) { applyInvalid(); return; }

    const day: number = parseInt(match[1], 10);
    const month: number = parseInt(match[2], 10);
    const year: number = parseInt(match[3], 10);

    if (!Number.isFinite(day) || !Number.isFinite(month) || !Number.isFinite(year)) {
      applyInvalid(); return;
    }

    if (month < 1 || month > 12) {applyInvalid(); return;}

    const daysInMonth: number = new Date(year, month, 0).getDate();
    if (day < 1 || day > daysInMonth) {applyInvalid(); return;}

    const parsed = new Date(year, month - 1, day);
    if (parsed.getFullYear() !== year
      || parsed.getMonth() !== month - 1
      || parsed.getDate() !== day
      || isNaN(parsed.getTime())
    ) {
      applyInvalid(); return;
    }

    if (ctrl) {
      ctrl.setValue(parsed, { emitEvent: false });
      ctrl.updateValueAndValidity({ onlySelf: true, emitEvent: false });
      removeInvalidFlagIfPresent();
    }
  }