package input

import (
	"bufio"
	"os"

	log "github.com/sirupsen/logrus"
)

// Validator represent signature of the input validation function.
type Validator func(in string) (string, error)

// Ask will ask user for an input and check validity with provided fn function.
func Ask(mandatory bool, fn Validator) string {
	scanner := bufio.NewScanner(os.Stdin)
	for {

		scanner.Scan()
		userInput := scanner.Text()

		if userInput == "" {

			if mandatory {
				log.Warn("Empty input, try again")
				continue
			}

			return userInput
		}

		value, err := fn(userInput)

		if err != nil {
			log.Warnf("%s", err.Error())
			continue
		}

		return value
	}
}