package smtpd

import (
	"container/list"
	"crypto/sha1"
	"fmt"
	"io"
	"strings"
)

// Take "user+ext@host.com" and return "user", aka the mailbox we'll store it in
func ParseMailboxName(emailAddress string) (result string) {
	result = strings.ToLower(emailAddress)
	if idx := strings.Index(result, "@"); idx > -1 {
		result = result[0:idx]
	}
	if idx := strings.Index(result, "+"); idx > -1 {
		result = result[0:idx]
	}
	return result
}

// Take a mailbox name and hash it into the directory we'll store it in
func HashMailboxName(mailbox string) string {
	h := sha1.New()
	io.WriteString(h, mailbox)
	return fmt.Sprintf("%x", h.Sum(nil))
}

// JoinStringList joins a List containing strings by commas
func JoinStringList(listOfStrings *list.List) string {
	if listOfStrings.Len() == 0 {
		return ""
	}
	s := make([]string, 0, listOfStrings.Len())
	for e := listOfStrings.Front(); e != nil; e = e.Next() {
		s = append(s, e.Value.(string))
	}
	return strings.Join(s, ",")
}