1 files changed, 20 insertions, 0 deletions
diff --git a/hotline/presence.go b/hotline/presence.go
new file mode 100644
index 0000000..7e41357
--- /dev/null
+++ b/hotline/presence.go
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+package hotline
+
+// PresenceTracker receives best-effort notifications about user session lifecycle
+// events so an external system (e.g. Redis) can maintain a list of online users.
+//
+// It is optional: when a Server has no PresenceTracker, online presence is derived
+// from the in-memory ClientManager instead. Implementations must be safe for
+// concurrent use by multiple goroutines.
+type PresenceTracker interface {
+	// UserConnected is called after a successful login, before the nickname is known.
+	UserConnected(login, ip string)
+
+	// UserRenamed is called when a user's nickname is set or changed. oldNickname is
+	// empty the first time a nickname is set (e.g. the 1.2.3 login flow or TranAgreed).
+	UserRenamed(login, oldNickname, newNickname, ip string)
+
+	// UserDisconnected is called when a user's session ends. nickname is empty if the
+	// user disconnected before setting one.
+	UserDisconnected(login, nickname, ip string)
+}