package https

import (
	"path/filepath"
	"strings"

	"github.com/miekg/coredns/core/assets"
)

// storage is used to get file paths in a consistent,
// cross-platform way for persisting Let's Encrypt assets
// on the file system.
var storage = Storage(filepath.Join(assets.Path(), "letsencrypt"))

// Storage is a root directory and facilitates
// forming file paths derived from it.
type Storage string

// Sites gets the directory that stores site certificate and keys.
func (s Storage) Sites() string {
	return filepath.Join(string(s), "sites")
}

// Site returns the path to the folder containing assets for domain.
func (s Storage) Site(domain string) string {
	return filepath.Join(s.Sites(), domain)
}

// SiteCertFile returns the path to the certificate file for domain.
func (s Storage) SiteCertFile(domain string) string {
	return filepath.Join(s.Site(domain), domain+".crt")
}

// SiteKeyFile returns the path to domain's private key file.
func (s Storage) SiteKeyFile(domain string) string {
	return filepath.Join(s.Site(domain), domain+".key")
}

// SiteMetaFile returns the path to the domain's asset metadata file.
func (s Storage) SiteMetaFile(domain string) string {
	return filepath.Join(s.Site(domain), domain+".json")
}

// Users gets the directory that stores account folders.
func (s Storage) Users() string {
	return filepath.Join(string(s), "users")
}

// User gets the account folder for the user with email.
func (s Storage) User(email string) string {
	if email == "" {
		email = emptyEmail
	}
	return filepath.Join(s.Users(), email)
}

// UserRegFile gets the path to the registration file for
// the user with the given email address.
func (s Storage) UserRegFile(email string) string {
	if email == "" {
		email = emptyEmail
	}
	fileName := emailUsername(email)
	if fileName == "" {
		fileName = "registration"
	}
	return filepath.Join(s.User(email), fileName+".json")
}

// UserKeyFile gets the path to the private key file for
// the user with the given email address.
func (s Storage) UserKeyFile(email string) string {
	if email == "" {
		email = emptyEmail
	}
	fileName := emailUsername(email)
	if fileName == "" {
		fileName = "private"
	}
	return filepath.Join(s.User(email), fileName+".key")
}

// emailUsername returns the username portion of an
// email address (part before '@') or the original
// input if it can't find the "@" symbol.
func emailUsername(email string) string {
	at := strings.Index(email, "@")
	if at == -1 {
		return email
	} else if at == 0 {
		return email[1:]
	}
	return email[:at]
}