feat: implement API for deleting Twitter user

Author: russellwheatley

FirebaseSwiftUI/FirebaseTwitterSwiftUI/Sources/Services/AccountService+Twitter.swift

@@ -0,0 +1,46 @@
+//
+//  AccountService+Twitter.swift
+//  FirebaseUI
+//
+//  Created by Russell Wheatley on 10/10/2025.
+//
+
+@preconcurrency import FirebaseAuth
+import FirebaseAuthSwiftUI
+import Observation
+
+protocol GoogleOperationReauthentication {
+  var twitterProvider: TwitterProviderSwift { get }
+}
+
+extension GoogleOperationReauthentication {
+  @MainActor func reauthenticate() async throws -> AuthenticationToken {
+    guard let user = Auth.auth().currentUser else {
+      throw AuthServiceError.reauthenticationRequired("No user currently signed-in")
+    }
+
+    do {
+      let credential = try await twitterProvider.createAuthCredential()
+      try await user.reauthenticate(with: credential)
+
+      return .firebase("")
+    } catch {
+      throw AuthServiceError.signInFailed(underlying: error)
+    }
+  }
+}
+
+@MainActor
+class TwitterDeleteUserOperation: AuthenticatedOperation,
+  @preconcurrency GoogleOperationReauthentication {
+  let twitterProvider: TwitterProviderSwift
+  init(twitterProvider: TwitterProviderSwift) {
+    self.twitterProvider = twitterProvider
+  }
+
+  func callAsFunction(on user: User) async throws {
+    try await callAsFunction(on: user) {
+      try await user.delete()
+    }
+  }
+}

FirebaseSwiftUI/FirebaseTwitterSwiftUI/Sources/Services/TwitterProviderAuthUI.swift

@@ -44,21 +44,21 @@ public class TwitterProviderSwift: AuthProviderSwift {
   }
 }
 
-public class TwitterProviderAuthUI: AuthProviderUI {
+public class TwitterProviderAuthUI: AuthProviderUI, DeleteUserSwift {
   public var provider: AuthProviderSwift
 
   public init(provider: AuthProviderSwift) {
     self.provider = provider
   }
 
-  public let id: String = "twitter"
+  public let id: String = "twitter.com"
 
   @MainActor public func authButton() -> AnyView {
     AnyView(SignInWithTwitterButton(provider: provider))
   }
 
-  // TODO: need to implement delete user protocol
-//  @MainActor public func deleteUser(user _: User) async throws {
-//    <#code#>
-//  }
+  public func deleteUser(user: User) async throws {
+    let operation = TwitterDeleteUserOperation(twitterProvider: provider as! TwitterProviderSwift)
+    try await operation(on: user)
+  }
 }