Add login_hint to FUIOAuth. (#663)

Author: Yue-Wang-Google

OAuth/FirebaseOAuthUI/FUIOAuth.h

@@ -46,6 +46,9 @@ NS_ASSUME_NONNULL_BEGIN
     @param iconImage The icon image of the provider.
     @param scopes Array used to configure the OAuth scopes.
     @param customParameters Dictionary used to configure the OAuth custom parameters.
+    @param loginHintKey The key of the custom parameter, with which the login hint can be passed to
+       the IdP.
+
  */
 - (instancetype)initWithAuthUI:(FUIAuth *)authUI
                     providerID:(NSString *)providerID
@@ -55,28 +58,9 @@ NS_ASSUME_NONNULL_BEGIN
                      iconImage:(UIImage *)iconImage
                         scopes:(nullable NSArray<NSString *> *)scopes
               customParameters:(nullable NSDictionary<NSString *, NSString*> *)customParameters
+                  loginHintKey:(nullable NSString *)loginHintKey
     NS_DESIGNATED_INITIALIZER;
 
-/** @fn providerID:buttonLabelText:buttonColor:iconImage:scopes:customParameters:
-    @brief Initialize the class instance with the default AuthUI.
-
-    @param providerID The unique identifier for the provider.
-    @param buttonLabelText The text label for the sign in button.
-    @param shortName A short display name for the provider.
-    @param buttonColor The background color that should be used for the sign in button of the
-        provider.
-    @param iconImage The icon image of the provider.
-    @param scopes Array used to configure the OAuth scopes.
-    @param customParameters Dictionary used to configure the OAuth custom parameters.
- */
-- (instancetype)initWithProviderID:(NSString *)providerID
-                   buttonLabelText:(NSString *)buttonLabelText
-                         shortName:(NSString *)shortName
-                       buttonColor:(UIColor *)buttonColor
-                         iconImage:(UIImage *)iconImage
-                            scopes:(nullable NSArray<NSString *> *)scopes
-                  customParameters:(nullable NSDictionary<NSString *, NSString*> *)customParameters;
-
 @end
 
 NS_ASSUME_NONNULL_END

OAuth/FirebaseOAuthUI/FUIOAuth.m

@@ -85,6 +85,11 @@ @interface FUIOAuth ()
  */
 @property(nonatomic, copy, nullable) NSDictionary<NSString *, NSString*> *customParameters;
 
+/** @property loginHintKey
+    @brief The key of the custom parameter, with which the login hint can be passed to the IdP.
+ */
+@property(nonatomic, copy, nullable) NSString *loginHintKey;
+
 /** @property provider
     @brief The OAuth provider that does the actual sign in.
  */
@@ -101,7 +106,8 @@ - (instancetype)initWithAuthUI:(FUIAuth *)authUI
                    buttonColor:(UIColor *)buttonColor
                      iconImage:(UIImage *)iconImage
                         scopes:(nullable NSArray<NSString *> *)scopes
-              customParameters:(nullable NSDictionary<NSString *, NSString*> *)customParameters {
+              customParameters:(nullable NSDictionary<NSString *, NSString*> *)customParameters
+                  loginHintKey:(nullable NSString *)loginHintKey {
   if (self = [super init]) {
     _authUI = authUI;
     _providerID = providerID;
@@ -112,29 +118,11 @@ - (instancetype)initWithAuthUI:(FUIAuth *)authUI
     _scopes = scopes;
     _customParameters = customParameters;
     _provider = [FIROAuthProvider providerWithProviderID:self.providerID];
-    _provider.customParameters = self.customParameters;
-    _provider.scopes = self.scopes;
+    _loginHintKey = loginHintKey;
   }
   return self;
 }
 
-- (instancetype)initWithProviderID:(NSString *)providerID
-                   buttonLabelText:(NSString *)buttonLabelText
-                         shortName:(NSString *)shortName
-                       buttonColor:(UIColor *)buttonColor
-                         iconImage:(UIImage *)iconImage
-                            scopes:(nullable NSArray<NSString *> *)scopes
-    customParameters:(nullable NSDictionary<NSString *, NSString*> *)customParameters {
-  return [self initWithAuthUI:[FUIAuth defaultAuthUI]
-                   providerID:providerID
-              buttonLabelText:buttonLabelText
-                    shortName:shortName
-                  buttonColor:buttonColor
-                    iconImage:iconImage
-                       scopes:scopes
-             customParameters:customParameters];
-}
-
 #pragma mark - FUIAuthProvider
 
 /** @fn accessToken:
@@ -171,6 +159,17 @@ - (void)signInWithDefaultValue:(nullable NSString *)defaultValue
                     completion:(nullable FUIAuthProviderSignInCompletionBlock)completion {
   self.presentingViewController = presentingViewController;
 
+  FIROAuthProvider *provider = self.provider;
+  provider.scopes = self.scopes;
+  NSMutableDictionary *customParameters = [NSMutableDictionary dictionary];
+  if (self.customParameters.count) {
+    [customParameters addEntriesFromDictionary:self.customParameters];
+  }
+  if (self.loginHintKey.length && defaultValue.length) {
+    customParameters[self.loginHintKey] = defaultValue;
+  }
+  provider.customParameters = [customParameters copy];
+
   [self.provider getCredentialWithUIDelegate:nil
                                   completion:^(FIRAuthCredential *_Nullable credential,
                                                NSError *_Nullable error) {

samples/objc/FirebaseUI-demo-objc/Samples/Auth/FUIAuthViewController.m

@@ -429,7 +429,8 @@ + (NSArray *)getListOfIDPs:(NSArray<NSIndexPath *> *)selectedRows
                                             buttonColor:buttonColor
                                               iconImage:[UIImage imageWithContentsOfFile:iconPath]
                                                  scopes:@[@"user.readwrite"]
-                                       customParameters:@{@"prompt" : @"consent"}];
+                                       customParameters:@{@"prompt" : @"consent"}
+                                           loginHintKey:@"login_hint"];
           }
           break;
         default: