1 files changed, 91 insertions, 0 deletions
diff --git a/session.go b/session.go
new file mode 100644
index 0000000..0aa5d5f
--- /dev/null
+++ b/session.go
@@ -0,0 +1,91 @@
+package koushin
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"sync"
+
+	imapclient "github.com/emersion/go-imap/client"
+)
+
+func generateToken() (string, error) {
+	b := make([]byte, 32)
+	_, err := rand.Read(b)
+	if err != nil {
+		return "", err
+	}
+	return base64.URLEncoding.EncodeToString(b), nil
+}
+
+var ErrSessionExpired = errors.New("session expired")
+
+type Session struct {
+	locker             sync.Mutex
+	imapConn           *imapclient.Client
+	username, password string
+}
+
+func (s *Session) Do(f func(*imapclient.Client) error) error {
+	s.locker.Lock()
+	defer s.locker.Unlock()
+
+	return f(s.imapConn)
+}
+
+// TODO: expiration timer
+type SessionManager struct {
+	locker   sync.Mutex
+	sessions map[string]*Session
+}
+
+func NewSessionManager() *SessionManager {
+	return &SessionManager{
+		sessions: make(map[string]*Session),
+	}
+}
+
+func (sm *SessionManager) Get(token string) (*Session, error) {
+	sm.locker.Lock()
+	defer sm.locker.Unlock()
+
+	session, ok := sm.sessions[token]
+	if !ok {
+		return nil, ErrSessionExpired
+	}
+	return session, nil
+}
+
+func (sm *SessionManager) Put(imapConn *imapclient.Client, username, password string) (token string, err error) {
+	sm.locker.Lock()
+	defer sm.locker.Unlock()
+
+	for {
+		var err error
+		token, err = generateToken()
+		if err != nil {
+			imapConn.Logout()
+			return "", err
+		}
+
+		if _, ok := sm.sessions[token]; !ok {
+			break
+		}
+	}
+
+	sm.sessions[token] = &Session{
+		imapConn: imapConn,
+		username: username,
+		password: password,
+	}
+
+	go func() {
+		<-imapConn.LoggedOut()
+
+		sm.locker.Lock()
+		delete(sm.sessions, token)
+		sm.locker.Unlock()
+	}()
+
+	return token, nil
+}