package set

import (
	"errors"
	"reflect"
	"strconv"
)

var (
	ErrTypeConvert = errors.New("cannot convert input")
)

func Field(dst interface{}, fieldName string, value string) error {

	valDst := reflect.ValueOf(dst).Elem()
	dstField := valDst.FieldByName(fieldName)

	val := reflect.ValueOf(value)
	if dstField.Kind() != val.Kind() {
		// try to convert
		switch dstField.Kind() {
		case reflect.Int:
			d, err := strconv.Atoi(value)
			if err != nil {
				return ErrTypeConvert
			}
			val = reflect.ValueOf(d)
		case reflect.Float64:
			f, err := strconv.ParseFloat(value, 64)
			if err != nil {
				return ErrTypeConvert
			}
			val = reflect.ValueOf(f)
		default:
			return ErrTypeConvert
		}
	}

	dstField.Set(val)
	return nil
}