1 files changed, 69 insertions, 0 deletions
diff --git a/persistence/sessions.go b/persistence/sessions.go
new file mode 100644
index 0000000..50e3f3e
--- /dev/null
+++ b/persistence/sessions.go
@@ -0,0 +1,69 @@
+package persistence
+
+import (
+	"github.com/pkg/errors"
+	"io/ioutil"
+
+	"dev.narayana.im/narayana/telegabber/yamldb"
+
+	"gopkg.in/yaml.v2"
+)
+
+// SessionsYamlDB wraps YamlDB with Session
+type SessionsYamlDB struct {
+	yamldb.YamlDB
+	Data *SessionsMap
+}
+
+// SessionsMap is for :sessions: subtree
+type SessionsMap struct {
+	Sessions map[string]Session `yaml:":sessions"`
+}
+
+// Session is a key-values subtree
+type Session struct {
+	Login string `yaml:":login"`
+}
+
+var sessionDB SessionsYamlDB
+
+// Marshaller implementation for YamlDB
+func Marshaller() ([]byte, error) {
+	return yaml.Marshal(sessionDB.Data)
+}
+
+// LoadSessions restores TDlib sessions from the previous run
+func LoadSessions(path string) (SessionsYamlDB, error) {
+	var sessionData SessionsMap
+
+	sessionDB, err := initYamlDB(path, &sessionData)
+	if err != nil {
+		return sessionDB, errors.Wrap(err, "Sessions restore error")
+	}
+
+	sessionDB.Transaction(func() {
+	}, Marshaller)
+
+	return sessionDB, nil
+}
+
+func initYamlDB(path string, dataPtr *SessionsMap) (SessionsYamlDB, error) {
+	file, err := ioutil.ReadFile(path)
+	if err == nil {
+		err = yaml.Unmarshal(file, dataPtr)
+		if err != nil {
+			return SessionsYamlDB{}, errors.Wrap(err, "YamlDB is corrupted")
+		}
+	} else {
+		// DB file does not exist, create an empty DB
+		dataPtr.Sessions = make(map[string]Session)
+	}
+
+	return SessionsYamlDB{
+		YamlDB: yamldb.YamlDB{
+			Path:    path,
+			PathNew: path + ".new",
+		},
+		Data: dataPtr,
+	}, nil
+}