import { useState, useEffect } from 'react';
import { useFormikContext, FieldMetaProps } from 'formik';

export function useTouchedHandler(name: string, meta: FieldMetaProps<any>) {
  const { setFieldTouched } = useFormikContext<any>();

  // use meta.touched as the initial value to keep the state,
  // in case this field was unmounted
  const [wasChanged, setWasChanged] = useState(meta.touched);

  // track if it was changed a least *once*
  useEffect(() => {
    if (meta.value !== meta.initialValue) {
      setWasChanged(true);
    }
  }, [meta.value, meta.initialValue]);

  useEffect(() => {
    // formik marks fields as *not* touched, if it was
    // *restored* to the initial value - but we *do* want that
    if (!meta.touched && wasChanged) {
      setFieldTouched(name, true, false);
      // on the other hand there can be cases (on blur) where the field
      // is marked as touched even though the user never entered something
      // - but we *don't* want that
    } else if (meta.touched && !wasChanged) {
      setFieldTouched(name, false, false);
    }
  }, [meta.touched, name, setFieldTouched, wasChanged]);
}