From 7177b9e927fd40c7fb671170c42ffd8779a1388a Mon Sep 17 00:00:00 2001
From: Artur Gurgul <artur@gurgul.pro>
Date: Sat, 2 Aug 2025 15:19:12 +0200
Subject: [PATCH] Add emitter so I can now send events to the RN core

---
 App.tsx                                       | 35 ++++++++++++-------
 ios/Native/Application/RootView.swift         |  3 +-
 .../Application/Shared/Emitter/Emitter.swift  | 32 +++++++++++++++++
 .../Shared/Emitter/EventEmitter.swift         | 28 +++++++++++++++
 .../Application/Shared/ModuleProvider.swift   |  0
 .../{ => Shared}/SharedState.swift            |  5 +++
 .../Application/Views/ToolboxHeader.swift     | 22 ++++++++++++
 7 files changed, 111 insertions(+), 14 deletions(-)
 create mode 100644 ios/Native/Application/Shared/Emitter/Emitter.swift
 create mode 100644 ios/Native/Application/Shared/Emitter/EventEmitter.swift
 create mode 100644 ios/Native/Application/Shared/ModuleProvider.swift
 rename ios/Native/Application/{ => Shared}/SharedState.swift (70%)
 create mode 100644 ios/Native/Application/Views/ToolboxHeader.swift

diff --git a/App.tsx b/App.tsx
index d091223..e7f33cf 100644
--- a/App.tsx
+++ b/App.tsx
@@ -1,19 +1,30 @@
-/**
- * Sample React Native App
- * https://github.com/facebook/react-native
- *
- * @format
- */
+import { NewAppScreen } from '@react-native/new-app-screen'
+import { useEffect, useState } from 'react'
+import { StatusBar, Text, StyleSheet, useColorScheme, View } from 'react-native'
+import { NativeEventEmitter, NativeModules } from 'react-native'
+const { Emitter } = NativeModules;
 
-import { NewAppScreen } from '@react-native/new-app-screen';
-import { StatusBar, StyleSheet, useColorScheme, View } from 'react-native';
+export default function App() {
+  const isDarkMode = useColorScheme() === 'dark'
+  const [message, setMessage] = useState(null)
+  
+  useEffect(() => {
+    const emitter = new NativeEventEmitter(Emitter);
+    const subscription = emitter.addListener('onMessage', (event) => {
+      if (event?.message) {
+        setMessage(event.message)
+      }
+    })
 
-function App() {
-  const isDarkMode = useColorScheme() === 'dark';
+    return () => {
+      subscription.remove()
+    };
+  }, [])
 
   return (
     <View style={styles.container}>
       <StatusBar barStyle={isDarkMode ? 'light-content' : 'dark-content'} />
+      <Text>{message ?? 'Waiting for message...'}</Text>
       <NewAppScreen templateFileName="App.tsx" />
     </View>
   );
@@ -23,6 +34,4 @@ const styles = StyleSheet.create({
   container: {
     flex: 1,
   },
-});
-
-export default App;
+})
diff --git a/ios/Native/Application/RootView.swift b/ios/Native/Application/RootView.swift
index c13bc1e..0cee3a5 100644
--- a/ios/Native/Application/RootView.swift
+++ b/ios/Native/Application/RootView.swift
@@ -15,10 +15,11 @@ struct RootView: View {
   
   var body: some View {
     VStack {
-      Text("Hello to SwiftUI!")
+      ToolboxHeader()
       if let reactNativeFactory = sharedState.reactNativeFactory {
         UIReactNativeView(reactNativeFactory)
       }
     }
+    .environmentObject(sharedState)
   }
 }
diff --git a/ios/Native/Application/Shared/Emitter/Emitter.swift b/ios/Native/Application/Shared/Emitter/Emitter.swift
new file mode 100644
index 0000000..1f66fd1
--- /dev/null
+++ b/ios/Native/Application/Shared/Emitter/Emitter.swift
@@ -0,0 +1,32 @@
+//
+//  Emitter.swift
+//  RNPlayground
+//
+//  Created by Artur Gurgul on 02/08/2025.
+//
+
+import Combine
+import React
+//import React_RCTAppDelegate
+//import ReactAppDependencyProvider
+
+@objc(Emitter)
+class Emitter: RCTEventEmitter {
+  override static func requiresMainQueueSetup() -> Bool {
+    return true
+  }
+  
+  override init() {
+    super.init()
+    EventEmitter.sharedInstance.register(eventEmitter: self)
+
+  }
+  
+  override func supportedEvents() -> [String]! {
+    return ["onMessage"]
+  }
+
+  @objc func send(message: String) {
+    sendEvent(withName: "onMessage", body: ["message": message])
+  }
+}
diff --git a/ios/Native/Application/Shared/Emitter/EventEmitter.swift b/ios/Native/Application/Shared/Emitter/EventEmitter.swift
new file mode 100644
index 0000000..f1a0e18
--- /dev/null
+++ b/ios/Native/Application/Shared/Emitter/EventEmitter.swift
@@ -0,0 +1,28 @@
+//
+//  EventEmitter.swift
+//  RNPlayground
+//
+//  Created by Artur Gurgul on 02/08/2025.
+//
+
+import Foundation
+
+class EventEmitter {
+  static let sharedInstance = EventEmitter()
+
+  private var eventEmitter: Emitter?
+
+  private init() {}
+
+  func register(eventEmitter: Emitter) {
+    self.eventEmitter = eventEmitter
+  }
+
+  func send(message: String) {
+    eventEmitter?.send(message: message)
+  }
+
+  var isReady: Bool {
+    return eventEmitter != nil
+  }
+}
diff --git a/ios/Native/Application/Shared/ModuleProvider.swift b/ios/Native/Application/Shared/ModuleProvider.swift
new file mode 100644
index 0000000..e69de29
diff --git a/ios/Native/Application/SharedState.swift b/ios/Native/Application/Shared/SharedState.swift
similarity index 70%
rename from ios/Native/Application/SharedState.swift
rename to ios/Native/Application/Shared/SharedState.swift
index b491d6e..cc073ba 100644
--- a/ios/Native/Application/SharedState.swift
+++ b/ios/Native/Application/Shared/SharedState.swift
@@ -13,4 +13,9 @@ import ReactAppDependencyProvider
 
 final class SharedState: ObservableObject {
   var reactNativeFactory: RCTReactNativeFactory?
+  private let emitter = EventEmitter.sharedInstance
+  
+  func send(message: String) {
+    emitter.send(message: message)
+  }
 }
diff --git a/ios/Native/Application/Views/ToolboxHeader.swift b/ios/Native/Application/Views/ToolboxHeader.swift
new file mode 100644
index 0000000..bee5d0c
--- /dev/null
+++ b/ios/Native/Application/Views/ToolboxHeader.swift
@@ -0,0 +1,22 @@
+//
+//  ToolboxHeader.swift
+//  RNPlayground
+//
+//  Created by Artur Gurgul on 02/08/2025.
+//
+
+import SwiftUI
+
+struct ToolboxHeader: View {
+  @EnvironmentObject var sharedState: SharedState
+  
+  var body: some View {
+    HStack {
+      Text("Actions")
+      Button("Make it blue") {
+        print("Making it blue")
+        sharedState.send(message: "hello from Swift!")
+      }
+    }
+  }
+}