package main

import (
	"crypto/ed25519"
	"errors"
	"github.com/emersion/go-imap/v2/imapserver"
	"github.com/google/uuid"
	"sync"
)

// OAuthConfig is the configuration for OAuth.
type OAuthConfig struct {
	HostName  string
	PublicKey ed25519.PublicKey
}

// Server is a server instance.
//
// A server contains a list of users.
type Server struct {
	config    OAuthConfig
	userMutex sync.Mutex
	users     map[uuid.UUID]*User
}

// New creates a new server.
func New(config OAuthConfig) *Server {
	return &Server{
		config: config,
		users:  make(map[uuid.UUID]*User),
	}
}

func (s *Server) userRaw(sub uuid.UUID) (*User, error) {
	s.userMutex.Lock()
	defer s.userMutex.Unlock()
	user, ok := s.users[sub]
	if !ok {
		user = &User{
			mailboxes: make(map[string]*Mailbox),
			sessions:  make(map[*UserSession]struct{}),
			server:    s,
			sub:       sub,
		}

		s.users[sub] = user

		_, err := user.mailbox("INBOX")
		if err != nil {
			if errors.Is(err, ErrNoSuchMailbox) {
				err := user.Create("INBOX", nil)
				if err != nil {
					return nil, err
				}
			} else {
				return nil, err
			}
		}
	}

	return user, nil
}

func (s *Server) user(token string) (*User, error) {
	sub, err := Authenticate(token, s.config)
	if err != nil {
		return nil, err
	}

	return s.userRaw(sub)
}

// NewSession creates a new IMAP session.
func (s *Server) NewSession() imapserver.Session {
	return s.newSession()
}

func (s *Server) newSession() *EntryPoint {
	return &EntryPoint{
		Server: s,
	}
}