Dispatcher.swift

public protocol Event {}

public enum Listener<E: Event> {
    public typealias T = E -> ()
}

public protocol Dispatcher {
    func listen<E: Event>(listener: Listener<E>.T)
    func fire<E: Event>(event: E)
    func push<E: Event>(event: E)
    func flush()
}

public class TestDispatcher: Dispatcher {
    var listeners = [String:[Any]]()
    var pushedEvents = [(Event.Type, Event)]()
    
    public init() {}
    
    public func listen<E: Event>(listener: Listener<E>.T) {
        var listeners = self.listeners[String(E.self)] ?? []
        listeners += [listener] as [Any]
        self.listeners[String(E.self)] = listeners
    }
    
    public func fire<E: Event>(event: E) {
        listeners[String(E.self)]?.forEach {
            let f = $0 as! Listener<E>.T
            f(event)
        }
    }
    
    public func push<E: Event>(event: E) {
        pushedEvents += [(E.self, event as Event)]
    }
    
    public func flush() {
        for (type, event) in pushedEvents {
            fire(event as type)
        }
    }
}