Update Loop Service

updateService.swift

import SpriteKit

class UpdateService {
    
    /// Handle on current SKScene
    let scene : Level
    
    /// Array of callbacks to be called each time the updateLoopRuns
    var updateListeners : Array<((CFTimeInterval) -> ())> = []
    
    init(scene: Level) {
        self.scene = scene
    }
    
    /// Add a callback function to the update cache.
    func addUpdateListener(listener:((CFTimeInterval) -> ())) {
        self.updateListeners.append(listener)
    }
    
    /// Reset the update cache.
    func clearUpdateCache() {
        self.updateListeners = []
    }
    
    /// Loop over desired items, update them, and then add callback to cache.
    func update(currentTime: CFTimeInterval) {
        if self.updateListeners.count > 0 {
            for listener in self.updateListeners {
                listener(currentTime)
            }
        }
        else {
            
            /// Update CharacterNodes
            self.scene.layers[WorldLayer.World.rawValue].enumerateChildNodesWithName("Character") {
                node, stop in
                    let realNode = node as CharacterNode
                    realNode.updateWithTime(currentTime)
                    self.addUpdateListener(realNode.updateWithTime)
            }
            
            /// Update Heraldry
            self.scene.layers[WorldLayer.World.rawValue].enumerateChildNodesWithName("Heraldry") {
                node, stop in
                    let realNode = node as Heraldry
                    realNode.updateWithTime(currentTime)
                    self.addUpdateListener(realNode.updateWithTime)
            }
        }
    }
}