ServerMultiplex: Introduces a server mutiplexer

- Also moves all the existing Wemo* stuff over to support the multiplexer
- Moves MainViewController to be the owner of the multiplexer, and its delegate

XIONControlPanel.xcodeproj/project.pbxproj

@@ -36,6 +36,9 @@
 		0CAA327D1C361ECA00B353CF /* StandardError.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0CAA327C1C361ECA00B353CF /* StandardError.swift */; };
 		0CF0F8961C362D8F00FE7752 /* NSURLAdditions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0CF0F8951C362D8F00FE7752 /* NSURLAdditions.swift */; };
 		0CF9A48E1C35E9C800276F13 /* SwitchIndicatorView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 0CF9A48D1C35E9C800276F13 /* SwitchIndicatorView.swift */; };
+		CD815B8E241C6F4000E2FA97 /* ServerProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = CD815B8D241C6F4000E2FA97 /* ServerProtocol.swift */; };
+		CD815B90241C7CAC00E2FA97 /* DeviceProtocol.swift in Sources */ = {isa = PBXBuildFile; fileRef = CD815B8F241C7CAC00E2FA97 /* DeviceProtocol.swift */; };
+		CD815B92241DA28B00E2FA97 /* ServerMultiplex.swift in Sources */ = {isa = PBXBuildFile; fileRef = CD815B91241DA28B00E2FA97 /* ServerMultiplex.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -73,6 +76,9 @@
 		0CAA327C1C361ECA00B353CF /* StandardError.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = StandardError.swift; sourceTree = "<group>"; };
 		0CF0F8951C362D8F00FE7752 /* NSURLAdditions.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NSURLAdditions.swift; sourceTree = "<group>"; };
 		0CF9A48D1C35E9C800276F13 /* SwitchIndicatorView.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = SwitchIndicatorView.swift; sourceTree = "<group>"; };
+		CD815B8D241C6F4000E2FA97 /* ServerProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ServerProtocol.swift; sourceTree = "<group>"; };
+		CD815B8F241C7CAC00E2FA97 /* DeviceProtocol.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeviceProtocol.swift; sourceTree = "<group>"; };
+		CD815B91241DA28B00E2FA97 /* ServerMultiplex.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ServerMultiplex.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -112,7 +118,6 @@
 				0C20E2BA1C33529700BA789B /* MainViewController.swift */,
 				0C41EF491C34B51500AF847F /* SwitchesViewController.swift */,
 				0C20E2BC1C33534F00BA789B /* VisualizationViewController.swift */,
-				0CAA32781C361A2400B353CF /* WemoServer.swift */,
 			);
 			path = Controllers;
 			sourceTree = "<group>";
@@ -120,6 +125,7 @@
 		0C20E2B71C33514100BA789B /* Models */ = {
 			isa = PBXGroup;
 			children = (
+				CD815B8F241C7CAC00E2FA97 /* DeviceProtocol.swift */,
 				0C4314FF1C35B1E700164559 /* WemoDevice.swift */,
 			);
 			path = Models;
@@ -169,6 +175,7 @@
 				0C20E2B61C33514100BA789B /* Controllers */,
 				0C41EF4B1C34B81F00AF847F /* External */,
 				0C20E2B71C33514100BA789B /* Models */,
+				CD815B8C241C6F2C00E2FA97 /* Servers */,
 				0C63A8741C3373BC007E4B52 /* Shaders */,
 				0C20E2C81C336F2E00BA789B /* Resources */,
 				0C63A8791C33C622007E4B52 /* Utilities */,
@@ -215,6 +222,16 @@
 			path = Utilities;
 			sourceTree = "<group>";
 		};
+		CD815B8C241C6F2C00E2FA97 /* Servers */ = {
+			isa = PBXGroup;
+			children = (
+				CD815B91241DA28B00E2FA97 /* ServerMultiplex.swift */,
+				CD815B8D241C6F4000E2FA97 /* ServerProtocol.swift */,
+				0CAA32781C361A2400B353CF /* WemoServer.swift */,
+			);
+			path = Servers;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXNativeTarget section */
@@ -305,6 +322,7 @@
 				0C41EF561C35ABCD00AF847F /* ConnectionStatusView.swift in Sources */,
 				0C63A87D1C33C655007E4B52 /* NSValue+XIONAdditions.m in Sources */,
 				0C20E2BD1C33534F00BA789B /* VisualizationViewController.swift in Sources */,
+				CD815B90241C7CAC00E2FA97 /* DeviceProtocol.swift in Sources */,
 				0C41EF4A1C34B51500AF847F /* SwitchesViewController.swift in Sources */,
 				0C20E2B91C33514100BA789B /* AppDelegate.swift in Sources */,
 				0C20E2BB1C33529700BA789B /* MainViewController.swift in Sources */,
@@ -312,6 +330,8 @@
 				0C21329B1C4DDC3E001E8F08 /* Semaphore.swift in Sources */,
 				0C41EF541C34BC9800AF847F /* XIONLogoView.swift in Sources */,
 				0C4315061C35E67600164559 /* WemoCellView.swift in Sources */,
+				CD815B92241DA28B00E2FA97 /* ServerMultiplex.swift in Sources */,
+				CD815B8E241C6F4000E2FA97 /* ServerProtocol.swift in Sources */,
 				0CAA327D1C361ECA00B353CF /* StandardError.swift in Sources */,
 				0CF9A48E1C35E9C800276F13 /* SwitchIndicatorView.swift in Sources */,
 				0C4315001C35B1E700164559 /* WemoDevice.swift in Sources */,

XIONControlPanel/Controllers/MainViewController.swift

@@ -8,9 +8,9 @@
 
 import UIKit
 
-class MainViewController: UIViewController, SwitchesViewControllerDelegate
+class MainViewController: UIViewController, SwitchesViewControllerDelegate, ServerMultiplexDelegate
 {
-    fileprivate var _server:                    WemoServer
+    fileprivate var _serverMultiplex:           ServerMultiplex = ServerMultiplex()
     fileprivate var _visualizationController:   VisualizationViewController = VisualizationViewController()
     fileprivate var _switchesController:        SwitchesViewController = SwitchesViewController()
     fileprivate var _headerView:                HeaderView = HeaderView()
@@ -18,10 +18,10 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
     
     override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?)
     {
-        let url = URL(string: "http://midna.xionsf.com:5000")!
-        _server = WemoServer(url)
-        
         super.init(nibName: nibNameOrNil, bundle: nibBundleOrNil)
+        
+        _serverMultiplex.delegate = self
+        _serverMultiplex.addServer(WemoServer(URL(string: "http://midna.xionsf.com:5000")!))
     }
     
     required init?(coder aDecoder: NSCoder)
@@ -104,16 +104,11 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
         
         _headerView.xionLogoView.beginAnimating()
         
-        if (!_server.connected) {
+        if _serverMultiplex.devices.count == 0 {
+            // Do initial refresh
             _updateConnectivityStatus(.connecting)
-            _server.connect { (error: Error?) -> Void in
+            _serverMultiplex.refreshDevices()
-                if (error == nil) {
+            _startUpdatingDevices()
-                    self._reloadDevices()
-                    self._startUpdatingDevices()
-                } else {
-                    self._updateConnectivityStatus(.error)
-                }
-            }
         }
     }
     
@@ -134,25 +129,14 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
         return true
     }
     
-    // MARK: API
-    
-    var devices: [WemoDevice] = []
-    {
-        didSet
-        {
-            _switchesController.devices = devices
-            _updateVisualization(false)
-        }
-    }
-    
     // MARK: SwitchesViewControllerDelegate
     
-    func switchesViewControllerDidToggleDevices(_ controller: SwitchesViewController, devices: [WemoDevice])
+    func switchesViewControllerDidToggleDevices(_ controller: SwitchesViewController, devices: [AnyDevice])
     {
         _updateVisualization(true)
         
         for device in devices {
-            _server.toggleDevice(device, state: device.state, completion: { (error: Error?) -> Void in })
+            _serverMultiplex.toggleDeviceState(device, state: device.state, completion: { (error: Error?) -> Void in })
         }
     }
     
@@ -179,14 +163,10 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
     
     internal func _updateVisualization(_ animated: Bool)
     {
-        var activatedDevicesCount = 0
+        let activatedDevicesCount = _serverMultiplex.devices.filter { $0.state == .on }.count
-        for device in self.devices {
+        let totalDeviceCount = _serverMultiplex.devices.count
-            if (device.state == .on) {
-                activatedDevicesCount += 1
-            }
-        }
         
-        let percentageActivated = (self.devices.count > 0 ? Float(activatedDevicesCount) / Float(self.devices.count) : 0.0)
+        let percentageActivated = (totalDeviceCount > 0 ? Float(activatedDevicesCount) / Float(totalDeviceCount) : 0.0)
         if (percentageActivated != _visualizationController.percentActivated) {
             _visualizationController.setPercentActivated(percentageActivated, animated: animated)
         }
@@ -201,21 +181,6 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
         }
     }
     
-    internal func _reloadDevices()
-    {
-        _server.fetchDevices({ (devices: [WemoDevice], error: Error?) -> Void in
-            DispatchQueue.main.async { () -> Void in
-                if (error == nil) {
-                    self.devices = devices
-                    self._updateConnectivityStatus(.connected)
-                } else {
-                    self.devices = []
-                    self._updateConnectivityStatus(.error)
-                }
-            }
-        })
-    }
-    
     internal func _startUpdatingDevices()
     {
         _updateDevices = true
@@ -223,7 +188,7 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
         let interval = DispatchTime.now() + Double(Int64(10 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)
         DispatchQueue.main.asyncAfter(deadline: interval) { () -> Void in
             if (self._updateDevices) {
-                self._reloadDevices()
+                self._serverMultiplex.refreshDevices()
                 self._startUpdatingDevices()
             }
         }
@@ -233,4 +198,28 @@ class MainViewController: UIViewController, SwitchesViewControllerDelegate
     {
         _updateDevices = false
     }
+    
+    // MARK: Server Multiplex Delegate
+    
+    func serverMultiplex(_ multiplex: ServerMultiplex, didAddDevices devices: [AnyDevice])
+    {
+        _switchesController.devices = devices
+        _updateVisualization(false)
+        
+        // Update connection status too, if applicable
+        if _serverMultiplex.numServers == _serverMultiplex.numberOfConnectedServers() {
+            _updateConnectivityStatus(.connected)
+        }
+    }
+    
+    func serverMultiplex(_ multiplex: ServerMultiplex, devicesStateChanged devices: [AnyDevice])
+    {
+        _switchesController.devicesStateChanged(devices)
+    }
+    
+    func serverMultiplex(_ multiplex: ServerMultiplex, didEncounterError error: Error)
+    {
+        _updateConnectivityStatus(.error)
+        print(error.localizedDescription)
+    }
 }

XIONControlPanel/Controllers/SwitchesViewController.swift

@@ -12,12 +12,7 @@ import UIKit
 
 protocol SwitchesViewControllerDelegate: class
 {
-    func switchesViewControllerDidToggleDevices(_ controller: SwitchesViewController, devices: [WemoDevice])
+    func switchesViewControllerDidToggleDevices(_ controller: SwitchesViewController, devices: [AnyDevice])
-}
-
-extension SwitchesViewControllerDelegate
-{
-    func switchesViewControllerDidToggleDevices(_ controller: SwitchesViewController, devices: [WemoDevice]) {}
 }
 
 class SwitchesViewController: UIViewController,
@@ -117,12 +112,12 @@ class SwitchesViewController: UIViewController,
     
     // MARK: API
     
-    var devices: [WemoDevice] = []
+    var devices: [AnyDevice] = []
     {
         didSet
         {
             // sort devices by name
-            self.devices.sort(by: { (d1: WemoDevice, d2: WemoDevice) -> Bool in
+            self.devices.sort(by: { (d1: Device, d2: Device) -> Bool in
                 return (d1.name.compare(d2.name, options: .caseInsensitive, range: nil, locale: nil) == .orderedAscending)
             })
             
@@ -132,6 +127,19 @@ class SwitchesViewController: UIViewController,
         }
     }
     
+    public func devicesStateChanged(_ changedDevices: [AnyDevice])
+    {
+        var snapshot = _collectionViewDataSource.snapshot()
+        changedDevices.forEach { changedDevice in
+            if let existingDevice = (self.devices.first { $0.hashValue == changedDevice.hashValue }) {
+                existingDevice.state = changedDevice.state
+                snapshot.reloadItems([ existingDevice.hashValue ])
+            }
+        }
+        
+        _collectionViewDataSource.apply(snapshot, animatingDifferences: true)
+    }
+    
     // MARK: UICollectionView
     
     func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath, identifier: Int) -> UICollectionViewCell?

XIONControlPanel/Models/DeviceProtocol.swift

@@ -0,0 +1,71 @@
+//
+//  DeviceProtocol.swift
+//  XIONControlPanel
+//
+//  Created by James Magahern on 3/13/20.
+//  Copyright © 2020 XION. All rights reserved.
+//
+
+import Foundation
+
+enum DeviceState
+{
+    case off
+    case on
+}
+
+enum DeviceType
+{
+    case `switch`
+}
+
+protocol Device
+{
+    // Read-only properties
+    var name:   String { get }
+    var serial: String { get }
+    var type:   DeviceType { get }
+    
+    // Writable properties
+    var state:  DeviceState { get set }
+}
+
+extension Device where Self: Hashable
+{
+    func hash(into hasher: inout Hasher)
+    {
+        hasher.combine(self.name)
+        hasher.combine(self.type)
+        hasher.combine(self.serial)
+    }
+    
+    static func == (lhs: Self, rhs: Self) -> Bool
+    {
+        return lhs.name == rhs.name && lhs.serial == rhs.serial
+    }
+}
+
+class AnyDevice : Device
+{
+    private var device: Device
+    
+    public var name: String
+        { get { return device.name } }
+    
+    public var serial: String
+        { get { return device.serial } }
+    
+    public var type: DeviceType
+        { get { return device.type } }
+    
+    public var state: DeviceState {
+        get { return device.state }
+        set { device.state = newValue }
+    }
+    
+    init(_ device: Device) {
+        self.device = device
+    }
+}
+
+extension AnyDevice : Hashable {}

XIONControlPanel/Models/WemoDevice.swift

@@ -8,23 +8,12 @@
 
 import Foundation
 
-class WemoDevice: Hashable
+class WemoDevice : Device
 {
-    enum State
-    {
-        case off
-        case on
-    }
-    
-    enum DeviceType
-    {
-        case `switch`
-    }
-    
     var name:   String = ""
     var host:   String = ""
     var model:  String = ""
-    var state:  State = .off
+    var state:  DeviceState = .off
     var type:   DeviceType = .switch
     var serial: String = ""
     

XIONControlPanel/Servers/ServerMultiplex.swift

@@ -0,0 +1,136 @@
+//
+//  ServerMultiplex.swift
+//  XIONControlPanel
+//
+//  Created by James Magahern on 3/14/20.
+//  Copyright © 2020 XION. All rights reserved.
+//
+
+import Foundation
+
+protocol ServerMultiplexDelegate
+{
+    func serverMultiplex(_ multiplex: ServerMultiplex, didAddDevices devices: [AnyDevice])
+    func serverMultiplex(_ multiplex: ServerMultiplex, devicesStateChanged devices: [AnyDevice])
+    func serverMultiplex(_ multiplex: ServerMultiplex, didEncounterError error: Error)
+}
+
+enum ServerMultiplexError : Error
+{
+    case UnknownDevice
+}
+
+class ServerMultiplex
+{
+    public var delegate: ServerMultiplexDelegate?
+    public private(set) var devices = Set<AnyDevice>()
+    
+    private var servers: [Server] = []
+    public var numServers: Int { get { return servers.count } }
+    
+    public func addServer(_ server: Server)
+    {
+        servers.append(server)
+    }
+    
+    public func numberOfConnectedServers() -> Int
+    {
+        return servers.filter { $0.connected == true }.count
+    }
+    
+    public func toggleDeviceState(_ device: AnyDevice, state: DeviceState, completion: @escaping (Error?) -> Void)
+    {
+        if let server = (servers.first { $0.responsibleForDevice(device) }) {
+            server.toggleDevice(device, state: state, completion: completion)
+            
+            // Update internal state
+            if let index = devices.firstIndex(of: device) {
+                devices[index].state = state
+            }
+        } else {
+            completion(ServerMultiplexError.UnknownDevice)
+        }
+    }
+    
+    public func refreshDevices()
+    {
+        ensureConnection { (error: Error?) in
+            if let error = error {
+                self.handleError(error)
+            } else {
+                self.servers.forEach { (server: Server) in
+                    server.fetchDevices { (result: Result<[AnyDevice], Error>) in
+                        self.handleServerFetchResult(result)
+                    }
+                }
+            }
+        }
+    }
+}
+
+extension ServerMultiplex
+{
+    private func ensureConnection(then: @escaping (Error?) -> Void)
+    {
+        let disconnectedServers = servers.filter { $0.connected == false }
+        var disconnectedServerCount = disconnectedServers.count
+        
+        if disconnectedServerCount > 0 {
+            disconnectedServers.forEach { (server: Server) in
+                server.connect { (error: Error?) in
+                    disconnectedServerCount -= 1
+                    if disconnectedServerCount == 0 {
+                        then(error)
+                    }
+                }
+            }
+        } else {
+            then(nil)
+        }
+    }
+    
+    private func handleServerFetchResult(_ result: Result<[AnyDevice], Error>)
+    {
+        switch result {
+        case .success(let devices):
+            handleDevicesChanged(devices)
+        case .failure(let error):
+            handleError(error)
+        }
+    }
+    
+    private func handleDevicesChanged(_ devicesChanged: [AnyDevice])
+    {
+        let newDevicesSet = Set<AnyDevice>(devicesChanged)
+        
+        let additions = newDevicesSet.subtracting(self.devices)
+        if additions.count > 0 {
+            DispatchQueue.main.async {
+                self.delegate?.serverMultiplex(self, didAddDevices: Array(additions))
+            }
+        }
+        
+        let changed = newDevicesSet.filter { (device: AnyDevice) in
+            if let existing = (devices.first { $0.hashValue == device.hashValue }) {
+                return existing.state != device.state
+            }
+            
+            return false
+        }
+        
+        if changed.count > 0 {
+            DispatchQueue.main.async {
+                self.delegate?.serverMultiplex(self, devicesStateChanged: Array(changed))
+            }
+        }
+        
+        self.devices = self.devices.union(newDevicesSet)
+    }
+    
+    private func handleError(_ error: Error)
+    {
+        DispatchQueue.main.async {
+            self.delegate?.serverMultiplex(self, didEncounterError: error)
+        }
+    }
+}

XIONControlPanel/Servers/ServerProtocol.swift

@@ -7,3 +7,27 @@
 //
 
 import Foundation
+
+protocol Server
+{
+    var connected: Bool { get }
+    
+    /// Designated initializer. Takes an API endpoint URL
+    init(_ url: URL)
+    
+    /// Attempts to connect to the server at the specified endpoint.
+    func connect(_ completion: @escaping (Error?) -> Void)
+    
+    /// Sets server's state as "disconnected"
+    func disconnect(_ completion: (Error?) -> Void)
+    
+    /// Fetches a list of all currently configured devices for this server, or returns an error.
+    func fetchDevices(_ completion: @escaping (Result<[AnyDevice], Error>) -> Void)
+    
+    /// Tells the server to set the state of a given device to the given state
+    func toggleDevice(_ device: AnyDevice, state: DeviceState, completion: @escaping (Error?) -> Void)
+    
+    /// Returns true if this is a device this server is responsible for
+    func responsibleForDevice(_ device: AnyDevice) -> Bool
+}
+

XIONControlPanel/Servers/WemoServer.swift

@@ -22,8 +22,10 @@ enum ConnectionError : Error
     case serverUnavailable
 }
 
-class WemoServer
+class WemoServer : Server
 {
+    private var devices: [WemoDevice] = []
+    
     fileprivate(set) var baseURL:    URL
     fileprivate(set) var connected:  Bool = false
     
@@ -31,7 +33,7 @@ class WemoServer
     fileprivate var _errorStream:    StandardErrorOutputStream = StandardErrorOutputStream()
     fileprivate var _operationQueue: OperationQueue = OperationQueue()
     
-    init(_ url: URL)
+    required init(_ url: URL)
     {
         self.baseURL = url
         
@@ -68,29 +70,32 @@ class WemoServer
         completion(nil)
     }
     
-    func fetchDevices(_ completion: @escaping ([WemoDevice], Error?) -> Void)
+    func fetchDevices(_ completion: @escaping (Result<[AnyDevice], Error>) -> Void)
     {
         if (self.connected) {
             let op = FetchDevicesOperation(baseURL: self.baseURL, session: _urlSession)
             weak var weakOp = op
             op.completionBlock = {
-                guard let strongOp = weakOp else { completion([], nil) ; return }
+                guard let strongOp = weakOp else { return }
                 if let error = strongOp.error {
                     self._logError("Error fetching devices", error: error)
+                    completion(.failure(error))
+                } else {
+                    self.devices = strongOp.devices
                 }
                 
-                completion(strongOp.devices, strongOp.error)
+                self.devices = strongOp.devices
+                completion(.success(self.devices.map { AnyDevice($0) }))
             }
             _operationQueue.addOperation(op)
         } else {
-            let err = ConnectionError.serverUnavailable
+            completion(.failure(ConnectionError.serverUnavailable))
-            completion([], err)
         }
     }
     
-    func toggleDevice(_ device: WemoDevice, state: WemoDevice.State, completion: @escaping (Error?) -> Void)
+    func toggleDevice(_ device: AnyDevice, state: DeviceState, completion: @escaping (Error?) -> Void)
     {
-        if (self.connected) {
+        if self.connected, let device = findDevice(device) {
             let op = ToggleDeviceOperation(baseURL: self.baseURL, session: _urlSession, device: device, state: state)
             weak var weakOp = op
             op.completionBlock = {
@@ -108,12 +113,22 @@ class WemoServer
         }
     }
     
+    func responsibleForDevice(_ device: AnyDevice) -> Bool
+    {
+        return self.devices.contains { $0.serial == device.serial }
+    }
+    
     // MARK: Internal
     
     internal func _logError(_ description: String, error: Error)
     {
         print("ERROR: \(description) \(error)", to: &_errorStream)
     }
+    
+    internal func findDevice(_ device: AnyDevice) -> WemoDevice?
+    {
+        return self.devices.first { $0.serial == device.serial }
+    }
 }
 
 internal class WemoOperation : Operation
@@ -188,9 +203,9 @@ internal class FetchDevicesOperation : WemoOperation
 internal class ToggleDeviceOperation : WemoOperation
 {
     var device: WemoDevice
-    var state:  WemoDevice.State
+    var state:  DeviceState
     
-    init(baseURL: URL, session: URLSession, device: WemoDevice, state: WemoDevice.State)
+    init(baseURL: URL, session: URLSession, device: WemoDevice, state: DeviceState)
     {
         self.device = device
         self.state = state