iOS broadcast implementation

ios/Classes/SwiftFlutterBroadcastsPlugin.swift

@@ -2,13 +2,160 @@ import Flutter
 import UIKit
 
 public class SwiftFlutterBroadcastsPlugin: NSObject, FlutterPlugin {
-  public static func register(with registrar: FlutterPluginRegistrar) {
-    let channel = FlutterMethodChannel(name: "flutter_broadcasts", binaryMessenger: registrar.messenger())
-    let instance = SwiftFlutterBroadcastsPlugin()
-    registrar.addMethodCallDelegate(instance, channel: channel)
-  }
+    enum ExternalCall: String {
+        case receiveBroadcast
+    }
+    enum SupportedCall: String {
+        case startReceiver, stopReceiver, sendBroadcast
+    }
+    enum ReceiverArgument: String {
+        case id, names
+    }
+    enum BroadcastArgument: String {
+        case name, data
+    }
+
+    typealias NameDataHandler = (_ name: String, _ data: [String: Any]) -> Void
+    typealias IdNamesHandler = (_ id: Int, _ names: [String]) -> Void
+
+    private static var broadcastManager: BroadcastManager?
+
+    public static func register(with registrar: FlutterPluginRegistrar) {
+        let channel = FlutterMethodChannel(name: "de.kevlatus.flutter_broadcasts", binaryMessenger: registrar.messenger())
+
+        broadcastManager = BroadcastManager(channel: channel)
+
+        let instance = SwiftFlutterBroadcastsPlugin()
+        registrar.addMethodCallDelegate(instance, channel: channel)
+    }
+
+    public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
+        guard let supportedCall = SupportedCall(rawValue: call.method) else {
+            result(FlutterMethodNotImplemented)
+            return
+        }
+        switch supportedCall {
+        case .startReceiver:
+            onStartReceiver(call: call, result: result)
+        case .stopReceiver:
+            onStopReceiver(call: call, result: result)
+        case .sendBroadcast:
+            onSendBroadcast(call: call, result: result)
+        }
+    }
+
+    private func withReceiverArgs(
+        _ call: FlutterMethodCall,
+        _ result: @escaping FlutterResult,
+        handler: IdNamesHandler) {
+            guard let args = call.arguments as? [String: Any],
+                  let id = args[ReceiverArgument.id.rawValue] as? Int else {
+                result("no receiver <\(ReceiverArgument.id.rawValue)> provided")
+                return
+            }
+            guard let names = args[ReceiverArgument.names.rawValue] as? [String] else {
+                result("no receiver <\(ReceiverArgument.names.rawValue)> provided")
+                return
+            }
+            handler(id, names)
+        }
+
+    private func withBroadcastArgs(
+        _ call: FlutterMethodCall,
+        _ result: @escaping FlutterResult,
+        handler: NameDataHandler){
+            guard let args = call.arguments as? [String: Any],
+                  let name = args[BroadcastArgument.name.rawValue] as? String else {
+                result("No broadcast <\(BroadcastArgument.name.rawValue)> provided")
+                return
+            }
+            let data = args[BroadcastArgument.data.rawValue] as? [String: Any] ?? [:]
+            handler(name, data)
+        }
+
+    private func onStartReceiver(call: FlutterMethodCall, result: @escaping FlutterResult) {
+        withReceiverArgs(call, result) { id, names in
+            Self.broadcastManager?.startReceiver(CustomBroadcastReceiver(id: id, names: names))
+            result(nil)
+        }
+    }
+
+    private func onStopReceiver(call: FlutterMethodCall, result: @escaping FlutterResult) {
+        withReceiverArgs(call, result) { id, _ in
+            Self.broadcastManager?.stopReceiver(with: id)
+            result(nil)
+        }
+    }
+
+    private func onSendBroadcast(call: FlutterMethodCall, result: @escaping FlutterResult) {
+        withBroadcastArgs(call, result) { name, data in
+            Self.broadcastManager?.sendBroadcast(name: name, data: data)
+            result(nil)
+        }
+    }
+}
+
+class CustomBroadcastReceiver {
+    let id: Int
+    let names: [String]
+    let handlers: [Any]
+
+    init(id: Int, names: [String], handlers: [Any] = []) {
+        self.id = id
+        self.names = names
+        self.handlers = handlers
+    }
+}
 
-  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
-    result("iOS " + UIDevice.current.systemVersion)
-  }
+class BroadcastManager {
+    enum BroadcastKeys: String {
+        case receiverId, name, data
+    }
+
+    let channel: FlutterMethodChannel
+
+    init(channel: FlutterMethodChannel) {
+        self.channel = channel
+    }
+
+    private var receivers: [Int: CustomBroadcastReceiver] = [:]
+
+    func startReceiver(_ receiver: CustomBroadcastReceiver) {
+        var handlers: [Any] = []
+        for name in receiver.names {
+            let handler = NotificationCenter.default.addObserver(forName: Notification.Name(name), object: nil, queue: nil) { [weak self] note in
+                self?.channel.invokeMethod(SwiftFlutterBroadcastsPlugin.ExternalCall.receiveBroadcast.rawValue, arguments: note.userInfo as? [String: Any])
+            }
+            handlers.append(handler)
+        }
+        receivers[receiver.id] = CustomBroadcastReceiver(id: receiver.id, names: receiver.names, handlers: handlers)
+    }
+
+    func stopReceiver(with id: Int) {
+        guard let receiver = receivers[id] else {
+            return
+        }
+        for handler in receiver.handlers {
+            NotificationCenter.default.removeObserver(handler)
+        }
+        receivers[id] = nil
+    }
+
+    func stopAll() {
+        for id in receivers.keys {
+            stopReceiver(with: id)
+        }
+    }
+
+    func sendBroadcast(name: String, data: [String: Any]) {
+        guard let receiver = receivers.values.first(where: { $0.names.contains(name) }) else {
+            return
+        }
+        let info: [String: Any] = [
+            BroadcastKeys.receiverId.rawValue: receiver.id,
+            BroadcastKeys.name.rawValue: name,
+            BroadcastKeys.data.rawValue: data,
+        ]
+        NotificationCenter.default.post(name: Notification.Name(name), object: nil, userInfo: info)
+    }
 }