package lulu

import (
	"fmt"
	"regexp"
)

var phoneExpr = regexp.MustCompile(`^\+?[\d\s\-.\/()]{8,20}$`)

type PhoneNumber string

func ParsePhoneNumber(s string) (PhoneNumber, error) {
	if phoneExpr.MatchString(s) {
		return PhoneNumber(s), nil
	}
	return "", fmt.Errorf("malformed phone number %q; must fit pattern `%s`", s, phoneExpr.String())
}

// MustParsePhoneNumber is like ParsePhoneNumber but panics if the phone
// number cannot be parsed.
func MustParsePhoneNumber(s string) PhoneNumber {
	n, err := ParsePhoneNumber(s)
	if err != nil {
		panic(fmt.Sprintf("lulu: ParsePhoneNumber(%q): %v", s, err))
	}
	return n
}

func (n *PhoneNumber) UnmarshalText(text []byte) error {
	pn, err := ParsePhoneNumber(string(text))
	if err != nil {
		return err
	}
	*n = pn
	return nil
}