refactor: allow providers to use whatever sign-in methods they wish

Author: russellwheatley

FirebaseSwiftUI/FirebaseAppleSwiftUI/Sources/Services/AppleProviderAuthUI.swift

@@ -114,7 +114,7 @@ extension AuthenticateWithAppleDialog: ASAuthorizationControllerDelegate {
 
 // MARK: - Apple Provider Swift
 
-public class AppleProviderSwift: AuthProviderSwift {
+public class AppleProviderSwift: CredentialAuthProviderSwift {
   public let scopes: [ASAuthorization.Scope]
   let providerId = "apple.com"
 
@@ -149,6 +149,6 @@ public class AppleProviderAuthUI: AuthProviderUI {
   public let id: String = "apple.com"
 
   @MainActor public func authButton() -> AnyView {
-    AnyView(SignInWithAppleButton(provider: provider))
+    AnyView(SignInWithAppleButton(provider: provider as! CredentialAuthProviderSwift))
   }
 }

FirebaseSwiftUI/FirebaseAppleSwiftUI/Sources/Views/SignInWithAppleButton.swift

@@ -20,8 +20,8 @@ import SwiftUI
 @MainActor
 public struct SignInWithAppleButton {
   @Environment(AuthService.self) private var authService
-  let provider: AuthProviderSwift
-  public init(provider: AuthProviderSwift) {
+  let provider: CredentialAuthProviderSwift
+  public init(provider: CredentialAuthProviderSwift) {
     self.provider = provider
   }
 }

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -17,7 +17,12 @@ import FirebaseAuthUIComponents
 import FirebaseCore
 import SwiftUI
 
-public protocol AuthProviderSwift {
+/// Base protocol for all authentication providers
+public protocol AuthProviderSwift {}
+
+/// Protocol for providers that can directly create an AuthCredential
+/// Used by Google, Apple, Twitter, Facebook, and OAuth providers
+public protocol CredentialAuthProviderSwift: AuthProviderSwift {
   @MainActor func createAuthCredential() async throws -> AuthCredential
 }
 
@@ -27,6 +32,9 @@ public protocol AuthProviderUI {
   var provider: AuthProviderSwift { get }
 }
 
+/// Protocol for phone authentication which requires a two-step flow:
+/// 1. Verify phone number to get verification ID
+/// 2. Create credential with verification ID and code
 public protocol PhoneAuthProviderSwift: AuthProviderSwift {
   @MainActor func verifyPhoneNumber(phoneNumber: String) async throws -> String
   @MainActor func createAuthCredential(verificationId: String,
@@ -189,7 +197,7 @@ public final class AuthService {
     )
   }
 
-  public func signIn(_ provider: AuthProviderSwift) async throws -> SignInOutcome {
+  public func signIn(_ provider: CredentialAuthProviderSwift) async throws -> SignInOutcome {
     do {
       let credential = try await provider.createAuthCredential()
       let result = try await signIn(credentials: credential)
@@ -829,8 +837,9 @@ public extension AuthService {
       let password = try await passwordPrompt.confirmPassword()
       let credential = EmailAuthProvider.credential(withEmail: email, password: password)
       _ = try await user.reauthenticate(with: credential)
-    } else if let matchingProvider = providers.first(where: { $0.id == providerId }) {
-      let credential = try await matchingProvider.provider.createAuthCredential()
+    } else if let matchingProvider = providers.first(where: { $0.id == providerId }),
+              let credentialProvider = matchingProvider.provider as? CredentialAuthProviderSwift {
+      let credential = try await credentialProvider.createAuthCredential()
       _ = try await user.reauthenticate(with: credential)
     } else {
       throw AuthServiceError.providerNotFound("No provider found for \(providerId)")

FirebaseSwiftUI/FirebaseFacebookSwiftUI/Sources/Services/FacebookProviderAuthUI.swift

@@ -19,7 +19,7 @@ import FirebaseAuth
 import FirebaseAuthSwiftUI
 import SwiftUI
 
-public class FacebookProviderSwift: AuthProviderSwift {
+public class FacebookProviderSwift: CredentialAuthProviderSwift {
   let scopes: [String]
   let providerId = "facebook.com"
   private let loginManager = LoginManager()

FirebaseSwiftUI/FirebaseFacebookSwiftUI/Sources/Views/SignInWithFacebookButton.swift

@@ -22,9 +22,9 @@ import SwiftUI
 @MainActor
 public struct SignInWithFacebookButton {
   @Environment(AuthService.self) private var authService
-  let facebookProvider: FacebookProviderSwift
+  let facebookProvider: CredentialAuthProviderSwift
 
-  public init(facebookProvider: FacebookProviderSwift) {
+  public init(facebookProvider: CredentialAuthProviderSwift) {
     self.facebookProvider = facebookProvider
   }
 }

FirebaseSwiftUI/FirebaseGoogleSwiftUI/Sources/Services/GoogleProviderAuthUI.swift

@@ -19,7 +19,7 @@ import GoogleSignIn
 import GoogleSignInSwift
 import SwiftUI
 
-public class GoogleProviderSwift: AuthProviderSwift {
+public class GoogleProviderSwift: CredentialAuthProviderSwift {
   let scopes: [String]
   let clientID: String
   let providerId = "google.com"
@@ -79,6 +79,6 @@ public class GoogleProviderAuthUI: AuthProviderUI {
   }
 
   @MainActor public func authButton() -> AnyView {
-    AnyView(SignInWithGoogleButton(googleProvider: provider))
+    AnyView(SignInWithGoogleButton(googleProvider: provider as! CredentialAuthProviderSwift))
   }
 }

FirebaseSwiftUI/FirebaseGoogleSwiftUI/Sources/Views/SignInWithGoogleButton.swift

@@ -26,9 +26,9 @@ import SwiftUI
 @MainActor
 public struct SignInWithGoogleButton {
   @Environment(AuthService.self) private var authService
-  let googleProvider: AuthProviderSwift
+  let googleProvider: CredentialAuthProviderSwift
 
-  public init(googleProvider: AuthProviderSwift) {
+  public init(googleProvider: CredentialAuthProviderSwift) {
     self.googleProvider = googleProvider
   }
 }

FirebaseSwiftUI/FirebaseOAuthSwiftUI/Sources/Services/OAuthProviderSwift.swift

@@ -18,7 +18,7 @@ import FirebaseCore
 import SwiftUI
 
 /// Configuration for a generic OAuth provider
-public class OAuthProviderSwift: AuthProviderSwift {
+public class OAuthProviderSwift: CredentialAuthProviderSwift {
   public let providerId: String
   public let scopes: [String]
   public let customParameters: [String: String]
@@ -130,6 +130,6 @@ public class OAuthProviderAuthUI: AuthProviderUI {
   }
 
   @MainActor public func authButton() -> AnyView {
-    AnyView(GenericOAuthButton(provider: provider))
+    AnyView(GenericOAuthButton(provider: provider as! CredentialAuthProviderSwift))
   }
 }

FirebaseSwiftUI/FirebaseOAuthSwiftUI/Sources/Views/GenericOAuthButton.swift

@@ -20,8 +20,8 @@ import SwiftUI
 @MainActor
 public struct GenericOAuthButton {
   @Environment(AuthService.self) private var authService
-  let provider: AuthProviderSwift
-  public init(provider: AuthProviderSwift) {
+  let provider: CredentialAuthProviderSwift
+  public init(provider: CredentialAuthProviderSwift) {
     self.provider = provider
   }
 }

FirebaseSwiftUI/FirebasePhoneAuthSwiftUI/Sources/Services/PhoneAuthProviderAuthUI.swift

@@ -34,10 +34,6 @@ public class PhoneProviderSwift: PhoneAuthProviderSwift {
     }
   }
 
-  @MainActor public func createAuthCredential() async throws -> AuthCredential {
-    fatalError("Not implemented")
-  }
-
   @MainActor public func createAuthCredential(verificationId: String,
                                               verificationCode: String) async throws
     -> AuthCredential {