stats

type Channel interface {
	// Runnable implies that Channel is a runnable unit.
	common.Runnable
	// Publish broadcasts a message through the channel with a controlling context.
	Publish(context.Context, interface{})
	// Subscribers returns all subscribers.
	Subscribers() []chan interface{}
	// Subscribe registers for listening to channel stream and returns a new listener channel.
	Subscribe() (chan interface{}, error)
	// Unsubscribe unregisters a listener channel from current Channel object.
	Unsubscribe(chan interface{}) error
}

type Counter interface {
	// Value is the current value of the counter.
	Value() int64
	// Set sets a new value to the counter, and returns the previous one.
	Set(int64) int64
	// Add adds a value to the current counter value, and returns the previous value.
	Add(int64) int64
}

type Manager interface {
	features.Feature

	// RegisterCounter registers a new counter to the manager. The identifier string must not be empty, and unique among other counters.
	RegisterCounter(string) (Counter, error)
	// UnregisterCounter unregisters a counter from the manager by its identifier.
	UnregisterCounter(string) error
	// GetCounter returns a counter by its identifier.
	GetCounter(string) Counter
	// VisitCounters calls visitor on all managed counters.
	// The visitor runs under a read lock; it must not call RegisterCounter or UnregisterCounter (would deadlock).
	VisitCounters(func(string, Counter) bool)

	// RegisterOnlineMap registers a new OnlineMap to the manager. The identifier string must not be empty, and unique among other OnlineMaps.
	RegisterOnlineMap(string) (OnlineMap, error)
	// UnregisterOnlineMap unregisters an OnlineMap from the manager by its identifier.
	UnregisterOnlineMap(string) error
	// GetOnlineMap returns an OnlineMap by its identifier.
	GetOnlineMap(string) OnlineMap
	// VisitOnlineMaps calls visitor on all managed online maps.
	// The visitor runs under a read lock; it must not call RegisterOnlineMap or UnregisterOnlineMap (would deadlock).
	VisitOnlineMaps(func(string, OnlineMap) bool)

	// RegisterChannel registers a new channel to the manager. The identifier string must not be empty, and unique among other channels.
	RegisterChannel(string) (Channel, error)
	// UnregisterChannel unregisters a channel from the manager by its identifier.
	UnregisterChannel(string) error
	// GetChannel returns a channel by its identifier.
	GetChannel(string) Channel

	// GetAllOnlineUsers returns all online users from all OnlineMaps.
	GetAllOnlineUsers() []string
}

type NoopManager struct{}

type OnlineMap interface {
	// Count returns the number of unique online IPs.
	Count() int
	// AddIP increments the reference count for the given IP.
	AddIP(string)
	// RemoveIP decrements the reference count for the given IP. Deletes at zero.
	RemoveIP(string)
	// ForEach calls fn for each online IP with its last-seen Unix timestamp.
	// If fn returns false, iteration stops.
	// The callback must not call AddIP/RemoveIP on the same OnlineMap (would deadlock).
	ForEach(func(string, int64) bool)
}