refactor(auth,apple): migrate iOS/macOS plugin implementation to Swift

packages/firebase_auth/firebase_auth/ios/firebase_auth.podspec

@@ -25,9 +25,9 @@ Pod::Spec.new do |s|
   s.authors          = 'The Chromium Authors'
   s.source           = { :path => '.' }
 
-  s.source_files     = 'firebase_auth/Sources/firebase_auth/**/*.{h,m}'
-  s.public_header_files = 'firebase_auth/Sources/firebase_auth/include/Public/**/*.h'
-  s.private_header_files = 'firebase_auth/Sources/firebase_auth/include/Private/**/*.h'
+  s.source_files     = 'firebase_auth/Sources/firebase_auth/**/*.swift'
+
+  s.swift_version = '5.0'
 
   s.ios.deployment_target = '15.0'
   s.dependency 'Flutter'

packages/firebase_auth/firebase_auth/ios/firebase_auth/Package.swift

@@ -35,8 +35,6 @@ let package = Package(
         .process("Resources")
       ],
       cSettings: [
-        .headerSearchPath("include/Private"),
-        .headerSearchPath("include/Public"),
         .define("LIBRARY_VERSION", to: "\"\(libraryVersion)\""),
         .define("LIBRARY_NAME", to: "\"flutter-fire-auth\""),
       ]

packages/firebase_auth/firebase_auth/ios/firebase_auth/Sources/firebase_auth/AuthConstants.swift

@@ -0,0 +1,24 @@
+// Copyright 2025 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+let kFLTFirebaseAuthChannelName = "plugins.flutter.io/firebase_auth"
+let kFirebaseAuthLibraryName = "flutter-fire-auth"
+let kFirebaseAuthLibraryVersion = "6.5.7"
+
+let kSignInMethodPassword = "password"
+let kSignInMethodEmailLink = "emailLink"
+let kSignInMethodFacebook = "facebook.com"
+let kSignInMethodGoogle = "google.com"
+let kSignInMethodGameCenter = "gc.apple.com"
+let kSignInMethodTwitter = "twitter.com"
+let kSignInMethodGithub = "github.com"
+let kSignInMethodApple = "apple.com"
+let kSignInMethodPhone = "phone"
+let kSignInMethodOAuth = "oauth"
+
+let kErrCodeNoCurrentUser = "no-current-user"
+let kErrMsgNoCurrentUser = "No user currently signed in."
+let kErrCodeInvalidCredential = "invalid-credential"
+let kErrMsgInvalidCredential =
+  "The supplied auth credential is malformed, has expired or is not currently supported."

packages/firebase_auth/firebase_auth/ios/firebase_auth/Sources/firebase_auth/AuthErrors.swift

@@ -0,0 +1,87 @@
+// Copyright 2025 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import FirebaseAuth
+import Foundation
+
+#if os(iOS)
+  import Flutter
+#elseif os(macOS)
+  import FlutterMacOS
+#endif
+
+enum AuthErrors {
+  static func convertToFlutterError(_ error: Error?) -> FlutterError {
+    var code = "unknown"
+    var message = "An unknown error has occurred."
+
+    guard let error = error as NSError? else {
+      return FlutterError(code: code, message: message, details: [:])
+    }
+
+    if let firebaseErrorCode = error.userInfo[AuthErrorUserInfoNameKey] as? String {
+      code = firebaseErrorCode.replacingOccurrences(of: "ERROR_", with: "")
+        .replacingOccurrences(of: "_", with: "-")
+        .lowercased()
+    }
+
+    if let localized = error.userInfo[NSLocalizedDescriptionKey] as? String {
+      message = localized
+    }
+
+    var additionalData: [String: Any] = [:]
+    if let email = error.userInfo[AuthErrorUserInfoEmailKey] as? String {
+      additionalData["email"] = email
+    }
+
+    let token = FLTFirebaseAuthPlugin.storeAuthCredentialIfPresent(error)
+    if let authCredential = error.userInfo[AuthErrorUserInfoUpdatedCredentialKey] as? AuthCredential
+    {
+      additionalData["authCredential"] = PigeonParser.getPigeonAuthCredential(
+        authCredential, token: token)
+    }
+
+    if message == "The password must be 6 characters long or more." {
+      message = "Password should be at least 6 characters"
+    }
+
+    return FlutterError(code: code, message: message, details: additionalData)
+  }
+
+  static func convertAppleAuthorizationErrorToFlutterError(_ error: Error) -> FlutterError {
+    let nsError = error as NSError
+    var message = "An unknown error has occurred."
+    if !nsError.localizedDescription.isEmpty {
+      message = nsError.localizedDescription
+    }
+
+    var additionalData: [String: Any] = [:]
+    let nativeErrorDomain = nsError.domain.isEmpty ? "unknown" : nsError.domain
+    additionalData["nativeErrorDomain"] = nativeErrorDomain
+    additionalData["nativeErrorCode"] = nsError.code
+
+    var underlyingMessage = ""
+    if let underlyingError = nsError.userInfo[NSUnderlyingErrorKey] as? NSError {
+      let underlyingErrorDomain =
+        underlyingError.domain.isEmpty ? "unknown" : underlyingError.domain
+      additionalData["underlyingNativeErrorDomain"] = underlyingErrorDomain
+      additionalData["underlyingNativeErrorCode"] = underlyingError.code
+      underlyingMessage =
+        ", Underlying Domain=\(underlyingErrorDomain) Code=\(underlyingError.code)"
+    }
+
+    let detailMessage =
+      "\(message) (Domain=\(nativeErrorDomain) Code=\(nsError.code)\(underlyingMessage))"
+    return FlutterError(code: "unknown", message: detailMessage, details: additionalData)
+  }
+
+  static func noCurrentUser() -> FlutterError {
+    FlutterError(code: kErrCodeNoCurrentUser, message: kErrMsgNoCurrentUser, details: nil)
+  }
+
+  static func invalidCredential() -> FlutterError {
+    FlutterError(
+      code: kErrCodeInvalidCredential, message: kErrMsgInvalidCredential, details: nil)
+  }
+}

packages/firebase_auth/firebase_auth/ios/firebase_auth/Sources/firebase_auth/FLTAuthStateChannelStreamHandler.swift

@@ -0,0 +1,48 @@
+// Copyright 2021 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import FirebaseAuth
+import Foundation
+
+#if os(iOS)
+  import Flutter
+#elseif os(macOS)
+  import FlutterMacOS
+#endif
+
+final class FLTAuthStateChannelStreamHandler: NSObject, FlutterStreamHandler {
+  private let auth: Auth
+  private var handle: AuthStateDidChangeListenerHandle?
+
+  init(auth: Auth) {
+    self.auth = auth
+  }
+
+  func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink)
+    -> FlutterError?
+  {
+    var initialAuthState = true
+    handle = auth.addStateDidChangeListener { auth, user in
+      if initialAuthState {
+        initialAuthState = false
+        return
+      }
+
+      if user != nil, let currentUser = auth.currentUser {
+        events(["user": PigeonParser.getManualList(PigeonParser.getPigeonDetails(currentUser))])
+      } else {
+        events(["user": NSNull()])
+      }
+    }
+    return nil
+  }
+
+  func onCancel(withArguments arguments: Any?) -> FlutterError? {
+    if let handle {
+      auth.removeStateDidChangeListener(handle)
+    }
+    handle = nil
+    return nil
+  }
+}