// Copyright 2021 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#import <TargetConditionals.h>

#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
#import <UIKit/UIKit.h>
#elif TARGET_OS_OSX
#import <AppKit/AppKit.h>
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST

#import <SafariServices/SafariServices.h>

#import <XCTest/XCTest.h>

// Test module imports
@import GoogleSignIn;

#import "GoogleSignIn/Sources/GIDAuthorizationFlowProcessor/API/GIDAuthorizationFlowProcessor.h"
#import "GoogleSignIn/Sources/GIDAuthorizationFlowProcessor/Implementations/Fakes/GIDFakeAuthorizationFlowProcessor.h"
#import "GoogleSignIn/Sources/GIDEMMSupport.h"
#import "GoogleSignIn/Sources/GIDGoogleUser_Private.h"
#import "GoogleSignIn/Sources/GIDSignIn_Private.h"
#import "GoogleSignIn/Sources/GIDSignInPreferences.h"
#import "GoogleSignIn/Sources/GIDKeychainHandler/Implementations/Fakes/GIDFakeKeychainHandler.h"
#import "GoogleSignIn/Sources/GIDHTTPFetcher/Implementations/Fakes/GIDFakeHTTPFetcher.h"
#import "GoogleSignIn/Sources/GIDHTTPFetcher/Implementations/GIDHTTPFetcher.h"
#import "GoogleSignIn/Sources/GIDProfileDataFetcher/API/GIDProfileDataFetcher.h"
#import "GoogleSignIn/Sources/GIDProfileDataFetcher/Implementations/Fakes/GIDFakeProfileDataFetcher.h"

#if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
#import "GoogleSignIn/Sources/GIDEMMErrorHandler.h"
#endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST

#import "GoogleSignIn/Tests/Unit/GIDFakeMainBundle.h"
#import "GoogleSignIn/Tests/Unit/GIDProfileData+Testing.h"
#import "GoogleSignIn/Tests/Unit/OIDAuthorizationResponse+Testing.h"
#import "GoogleSignIn/Tests/Unit/OIDTokenResponse+Testing.h"

#ifdef SWIFT_PACKAGE
@import AppAuth;
@import GTMAppAuth;
@import GTMSessionFetcherCore;
@import OCMock;
#else
#import <AppAuth/OIDAuthState.h>
#import <AppAuth/OIDAuthorizationRequest.h>
#import <AppAuth/OIDAuthorizationResponse.h>
#import <AppAuth/OIDAuthorizationService.h>
#import <AppAuth/OIDError.h>
#import <AppAuth/OIDGrantTypes.h>
#import <AppAuth/OIDTokenRequest.h>
#import <AppAuth/OIDTokenResponse.h>
#import <AppAuth/OIDURLQueryComponent.h>

#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
#import <AppAuth/OIDAuthorizationService+IOS.h>
#elif TARGET_OS_OSX
#import <AppAuth/OIDAuthorizationService+Mac.h>
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST

#import <GTMAppAuth/GTMAppAuthFetcherAuthorization+Keychain.h>
#import <GTMAppAuth/GTMAppAuthFetcherAuthorization.h>
#import <GTMSessionFetcher/GTMSessionFetcher.h>
#import <OCMock/OCMock.h>
#endif

// Create a BLOCK to store the actual address for arg in param.
#define SAVE_TO_ARG_BLOCK(param) [OCMArg checkWithBlock:^(id arg) {\
    param = arg;\
    return YES;\
}]

#define COPY_TO_ARG_BLOCK(param) [OCMArg checkWithBlock:^(id arg) {\
    param = [arg copy];\
    return YES;\
}]

static NSString * const kFakeGaiaID = @"123456789";
static NSString * const kFakeIDToken = @"FakeIDToken";
static NSString * const kClientId = @"FakeClientID";
static NSString * const kDotReversedClientId = @"FakeClientID";
static NSString * const kClientId2 = @"FakeClientID2";
static NSString * const kServerClientId = @"FakeServerClientID";
static NSString * const kLanguage = @"FakeLanguage";
static NSString * const kAuthCode = @"FakeAuthCode";
static NSString * const kKeychainName = @"auth";
static NSString * const kUserEmail = @"FakeUserEmail";
static NSString * const kVerifier = @"FakeVerifier";
static NSString * const kOpenIDRealm = @"FakeRealm";
static NSString * const kFakeHostedDomain = @"fakehosteddomain.com";
static NSString * const kFakeUserName = @"fake username";
static NSString * const kFakeUserGivenName = @"fake";
static NSString * const kFakeUserFamilyName = @"username";
static NSString * const kFakeUserPictureURL = @"fake_user_picture_url";

static NSString * const kContinueURL = @"com.google.UnitTests:/oauth2callback";
static NSString * const kContinueURLWithClientID = @"FakeClientID:/oauth2callback";
static NSString * const kWrongSchemeURL = @"wrong.app:/oauth2callback";
static NSString * const kWrongPathURL = @"com.google.UnitTests:/wrong_path";

static NSString * const kEMMRestartAuthURL =
     @"com.google.UnitTests:///emmcallback?action=restart_auth";
static NSString * const kEMMWrongPathURL =
     @"com.google.UnitTests:///unknowcallback?action=restart_auth";
static NSString * const kEMMWrongActionURL =
     @"com.google.UnitTests:///emmcallback?action=unrecognized";
static NSString * const kDevicePolicyAppBundleID = @"com.google.DevicePolicy";

static NSString * const kAppHasRunBeforeKey = @"GPP_AppHasRunBefore";

static NSString * const kFingerprintKeychainName = @"fingerprint";
static NSString * const kVerifierKeychainName = @"verifier";
static NSString * const kVerifierKey = @"verifier";
//static NSString * const kOpenIDRealmKey = @"openid.realm";
static NSString * const kSavedKeychainServiceName = @"saved-keychain";
static NSString * const kKeychainAccountName = @"GooglePlus";
static NSString * const kUserNameKey = @"name";
static NSString * const kUserGivenNameKey = @"givenName";
static NSString * const kUserFamilyNameKey = @"familyName";
static NSString * const kUserImageKey = @"picture";
static NSString * const kAppName = @"UnitTests";
static NSString * const kUserIDKey = @"userID";
static NSString * const kHostedDomainKey = @"hostedDomain";
static NSString * const kIDTokenExpirationKey = @"idTokenExp";

static NSString * const kCustomKeychainName = @"CUSTOM_KEYCHAIN_NAME";
static NSString * const kAddActivity = @"http://schemas.google.com/AddActivity";
static NSString * const kErrorDomain = @"ERROR_DOMAIN";
static NSInteger const kErrorCode = 212;

static NSString *const kDriveScope = @"https://www.googleapis.com/auth/drive";

static NSString *const kTokenURL = @"https://oauth2.googleapis.com/token";

static NSString *const kFakeURL = @"http://foo.com";

static NSString *const kNewScope = @"newScope";

#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
// This category is used to allow the test to swizzle a private method.
@interface UIViewController (Testing)

// This private method provides access to the window. It's declared here to avoid a warning about
// an unrecognized selector in the test.
- (UIWindow *)_window;

@end
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST

// This class extension exposes GIDSignIn methods to our tests.
@interface GIDSignIn ()

// Exposing private method so we can call it to disambiguate between interactive and non-interactive
// sign-in attempts for the purposes of testing the GIDSignInUIDelegate (which should not be
// called in the case of a non-interactive sign in).
- (void)authenticateMaybeInteractively:(BOOL)interactive withParams:(NSDictionary *)params;

- (BOOL)assertValidPresentingViewContoller;

@end

@interface GIDSignInTest : XCTestCase {
@private
  // Whether or not the OS version is eligible for EMM.
  BOOL _isEligibleForEMM;

  // Mock `OIDAuthState`.
  id _authState;

  // Mock `OIDTokenResponse`.
  id _tokenResponse;

  // Mock `OIDTokenRequest`.
  id _tokenRequest;

  // Mock `GTMAppAuthFetcherAuthorization`.
  id _authorization;
  
  // Fake for `GIDKeychainHandler`.
  GIDFakeKeychainHandler *_keychainHandler;

  // Fake for `GIDHTTPFetcher`.
  GIDFakeHTTPFetcher *_httpFetcher;
  
  // Fake for `GIDAuthorizationFlowProcessor`.
  GIDFakeAuthorizationFlowProcessor *_authorizationFlowProcessor;

  // Fake for `GIDProfileDataFetcher`.
  GIDFakeProfileDataFetcher *_profileDataFetcher;
  
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
  // Mock `UIViewController`.
  id _presentingViewController;
#elif TARGET_OS_OSX
  // Mock `NSWindow`.
  id _presentingWindow;
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST

  // Mock for `GIDGoogleUser`.
  id _user;

  // Mock for `OIDAuthorizationService`.
  id _oidAuthorizationService;

  // Parameter saved from delegate call.
  NSError *_authError;

  // Whether callback block has been called.
  BOOL _completionCalled;

  // Fake [NSBundle mainBundle];
  GIDFakeMainBundle *_fakeMainBundle;

  // The `GIDSignIn` object being tested.
  GIDSignIn *_signIn;

  // The configuration to be used when testing `GIDSignIn`.
  GIDConfiguration *_configuration;

  // The completion to be used when testing `GIDSignIn`.
  GIDSignInCompletion _completion;

  // The saved token request callback.
  OIDTokenCallback _savedTokenCallback;
}
@end

@implementation GIDSignInTest

#pragma mark - Lifecycle

- (void)setUp {
  [super setUp];
#if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
  _isEligibleForEMM = [UIDevice currentDevice].systemVersion.integerValue >= 9;
#endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST

  // States
  _completionCalled = NO;

  // Mocks
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
  _presentingViewController = OCMStrictClassMock([UIViewController class]);
#elif TARGET_OS_OSX
  _presentingWindow = OCMStrictClassMock([NSWindow class]);
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST
  _authState = OCMStrictClassMock([OIDAuthState class]);
  OCMStub([_authState alloc]).andReturn(_authState);
  OCMStub([_authState initWithAuthorizationResponse:OCMOCK_ANY]).andReturn(_authState);
  _tokenResponse = OCMStrictClassMock([OIDTokenResponse class]);
  _tokenRequest = OCMStrictClassMock([OIDTokenRequest class]);
  _authorization = OCMStrictClassMock([GTMAppAuthFetcherAuthorization class]);
  OCMStub([_authorization alloc]).andReturn(_authorization);
  OCMStub([_authorization initWithAuthState:OCMOCK_ANY]).andReturn(_authorization);
  _user = OCMStrictClassMock([GIDGoogleUser class]);
  _oidAuthorizationService = OCMStrictClassMock([OIDAuthorizationService class]);
  OCMStub([self->_oidAuthorizationService
      performTokenRequest:OCMOCK_ANY
                 callback:COPY_TO_ARG_BLOCK(self->_savedTokenCallback)]);

  // Fakes
  _fakeMainBundle = [[GIDFakeMainBundle alloc] init];
  [_fakeMainBundle startFakingWithClientID:kClientId];
  [_fakeMainBundle fakeAllSchemesSupported];

  // Object under test
  [[NSUserDefaults standardUserDefaults] setBool:YES
                                          forKey:kAppHasRunBeforeKey];

  _keychainHandler = [[GIDFakeKeychainHandler alloc] init];
  
  _httpFetcher = [[GIDFakeHTTPFetcher alloc] init];
  
  _authorizationFlowProcessor = [[GIDFakeAuthorizationFlowProcessor alloc] init];
  
  _profileDataFetcher = [[GIDFakeProfileDataFetcher alloc] init];
  
  _signIn = [[GIDSignIn alloc] initWithKeychainHandler:_keychainHandler
                                           httpFetcher:_httpFetcher
                                    profileDataFetcher:_profileDataFetcher
                            authorizationFlowProcessor:_authorizationFlowProcessor];

  __weak GIDSignInTest *weakSelf = self;
  _completion = ^(GIDSignInResult *_Nullable signInResult, NSError * _Nullable error) {
    GIDSignInTest *strongSelf = weakSelf;
    if (!signInResult) {
      XCTAssertNotNil(error, @"should have an error if the signInResult is nil");
    }
    XCTAssertFalse(strongSelf->_completionCalled, @"callback already called");
    strongSelf->_completionCalled = YES;
    strongSelf->_authError = error;
  };
}

- (void)tearDown {
  OCMVerifyAll(_authState);
  OCMVerifyAll(_tokenResponse);
  OCMVerifyAll(_tokenRequest);
  OCMVerifyAll(_user);
//  OCMVerifyAll(_oidAuthorizationService);

#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
  OCMVerifyAll(_presentingViewController);
#elif TARGET_OS_OSX
  OCMVerifyAll(_presentingWindow);
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST

  [_fakeMainBundle stopFaking];
  [super tearDown];
}

#pragma mark - Tests

- (void)testShareInstance {
  GIDSignIn *signIn1 = GIDSignIn.sharedInstance;
  GIDSignIn *signIn2 = GIDSignIn.sharedInstance;
  XCTAssertTrue(signIn1 == signIn2, @"shared instance must be singleton");
}

- (void)testInitPrivate {
  GIDSignIn *signIn = [[GIDSignIn alloc] initPrivate];
  XCTAssertNotNil(signIn.configuration);
  XCTAssertEqual(signIn.configuration.clientID, kClientId);
  XCTAssertNil(signIn.configuration.serverClientID);
  XCTAssertNil(signIn.configuration.hostedDomain);
  XCTAssertNil(signIn.configuration.openIDRealm);
}

- (void)testInitPrivate_noConfig {
  [_fakeMainBundle fakeWithClientID:nil
                     serverClientID:nil
                       hostedDomain:nil
                        openIDRealm:nil];
  GIDSignIn *signIn = [[GIDSignIn alloc] initPrivate];
  XCTAssertNil(signIn.configuration);
}

- (void)testInitPrivate_fullConfig {
  [_fakeMainBundle fakeWithClientID:kClientId
                     serverClientID:kServerClientId
                       hostedDomain:kFakeHostedDomain
                        openIDRealm:kOpenIDRealm];
  GIDSignIn *signIn = [[GIDSignIn alloc] initPrivate];
  XCTAssertNotNil(signIn.configuration);
  XCTAssertEqual(signIn.configuration.clientID, kClientId);
  XCTAssertEqual(signIn.configuration.serverClientID, kServerClientId);
  XCTAssertEqual(signIn.configuration.hostedDomain, kFakeHostedDomain);
  XCTAssertEqual(signIn.configuration.openIDRealm, kOpenIDRealm);
}

- (void)testInitPrivate_invalidConfig {
  [_fakeMainBundle fakeWithClientID:@[ @"bad", @"config", @"values" ]
                     serverClientID:nil
                       hostedDomain:nil
                        openIDRealm:nil];
  GIDSignIn *signIn = [[GIDSignIn alloc] initPrivate];
  XCTAssertNil(signIn.configuration);
}

- (void)testRestorePreviousSignInNoRefresh_hasPreviousUser {
  [[[_authorization stub] andReturn:_authState] authState];
  [[_authorization expect] setTokenRefreshDelegate:OCMOCK_ANY];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_authState refreshToken]).andReturn(kRefreshToken);
  [[_authState expect] setStateChangeDelegate:OCMOCK_ANY];
  [_keychainHandler saveAuthState:_authState];

  id idTokenDecoded = OCMClassMock([OIDIDToken class]);
  OCMStub([idTokenDecoded alloc]).andReturn(idTokenDecoded);
  OCMStub([idTokenDecoded initWithIDTokenString:OCMOCK_ANY]).andReturn(idTokenDecoded);
  OCMStub([idTokenDecoded subject]).andReturn(kFakeGaiaID);
  
  // Mock generating a GIDConfiguration when initializing GIDGoogleUser.
  OIDAuthorizationResponse *authResponse =
      [OIDAuthorizationResponse testInstanceWithAdditionalParameters:nil
                                                         errorString:nil];
  
  OCMStub([_authState lastAuthorizationResponse]).andReturn(authResponse);
  OCMStub([_tokenResponse idToken]).andReturn(kFakeIDToken);
  OCMStub([_tokenResponse accessToken]).andReturn(kAccessToken);
  OCMStub([_tokenResponse accessTokenExpirationDate]).andReturn(nil);
  
  GIDProfileData *fakeProfileData = [GIDProfileData testInstance];
  GIDProfileDataFetcherTestBlock testBlock = ^(GIDProfileDataFetcherFakeResponseProvider
                                               responseProvider) {
    responseProvider(fakeProfileData, nil);
  };
  
  _profileDataFetcher.testBlock = testBlock;
  [_signIn restorePreviousSignInNoRefresh];

  XCTAssertEqual(_signIn.currentUser.userID, kFakeGaiaID);
  
  XCTAssertEqualObjects(_signIn.currentUser.profile, fakeProfileData);
  [idTokenDecoded stopMocking];
}

- (void)testRestoredPreviousSignInNoRefresh_hasNoPreviousUser {
  XCTAssertNil([_keychainHandler loadAuthState]);
  [_signIn restorePreviousSignInNoRefresh];

  XCTAssertNil(_signIn.currentUser);
}

- (void)testHasPreviousSignIn_HasBeenAuthenticated {
  [_keychainHandler saveAuthState:_authState];
  [[[_authState expect] andReturnValue:[NSNumber numberWithBool:YES]] isAuthorized];
  XCTAssertTrue([_signIn hasPreviousSignIn], @"should return |YES|");
  [_authState verify];
  XCTAssertFalse(_completionCalled, @"should not call delegate");
  XCTAssertNil(_authError, @"should have no error");
}

- (void)testHasPreviousSignIn_HasNotBeenAuthenticated {
  [_keychainHandler saveAuthState:_authState];
  [[[_authState expect] andReturnValue:[NSNumber numberWithBool:NO]] isAuthorized];
  XCTAssertFalse([_signIn hasPreviousSignIn], @"should return |NO|");
  [_authState verify];
  XCTAssertFalse(_completionCalled, @"should not call delegate");
}

- (void)testRestorePreviousSignInWhenSignedOut {
  [_keychainHandler saveAuthState:_authState];
  [[[_authState expect] andReturnValue:[NSNumber numberWithBool:NO]] isAuthorized];
  _completionCalled = NO;
  _authError = nil;

  XCTestExpectation *expectation = [self expectationWithDescription:@"Callback should be called."];

  [_signIn restorePreviousSignInWithCompletion:^(GIDGoogleUser *_Nullable user,
                                                 NSError * _Nullable error) {
    [expectation fulfill];
    XCTAssertNotNil(error, @"error should not have been nil");
    XCTAssertEqual(error.domain,
                   kGIDSignInErrorDomain,
                   @"error domain should have been the sign-in error domain.");
    XCTAssertEqual(error.code,
                   kGIDSignInErrorCodeHasNoAuthInKeychain,
                   @"error code should have been the 'NoAuthInKeychain' error code.");
  }];

  [self waitForExpectationsWithTimeout:1 handler:nil];
  [_authState verify];
}

- (void)testOAuthLogin {
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:NO
                     oldAccessToken:NO
                        modalCancel:NO];
}

- (void)testOAuthLogin_RestoredSignIn {
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:YES
                     oldAccessToken:NO
                        modalCancel:NO];
}

- (void)testOAuthLogin_RestoredSignInOldAccessToken {
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:YES
                     oldAccessToken:YES
                        modalCancel:NO];
}

- (void)testOAuthLogin_ConsentCanceled {
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:@"access_denied"
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:NO
                     oldAccessToken:NO
                        modalCancel:NO];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertTrue(_completionCalled, @"should call delegate");
  XCTAssertEqual(_authError.code, kGIDSignInErrorCodeCanceled);
}

- (void)testOAuthLogin_ModalCanceled {
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:NO
                     oldAccessToken:NO
                        modalCancel:YES];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertTrue(_completionCalled, @"should call delegate");
  XCTAssertEqual(_authError.code, kGIDSignInErrorCodeCanceled);
}

- (void)testOAuthLogin_KeychainError {
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:YES
                     restoredSignIn:NO
                     oldAccessToken:NO
                        modalCancel:NO];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertTrue(_completionCalled, @"should call delegate");
  XCTAssertEqualObjects(_authError.domain, kGIDSignInErrorDomain);
  XCTAssertEqual(_authError.code, kGIDSignInErrorCodeKeychain);
}

- (void)testSignOut {
  XCTAssert([_keychainHandler saveAuthState:_authState]);
  // Sign in a user so that we can then sign them out.
  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:YES
                     oldAccessToken:NO
                        modalCancel:NO];

  XCTAssertNotNil(_signIn.currentUser);
  XCTAssertNotNil([_keychainHandler loadAuthState]);

  [_signIn signOut];
  XCTAssertNil(_signIn.currentUser, @"should not have a current user");
  XCTAssertNil([_keychainHandler loadAuthState]);
}

- (void)testNotHandleWrongPath {
  XCTAssertFalse([_signIn handleURL:[NSURL URLWithString:kWrongPathURL]], @"should not handle URL");
  XCTAssertFalse(_completionCalled, @"should not call delegate");
}

#pragma mark - Tests - disconnectWithCallback:

// Verifies disconnect calls callback with no errors if access token is present.
- (void)testDisconnect_accessTokenIsPresent {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(kAccessToken);
  
  XCTestExpectation *fetcherExpectation =
      [self expectationWithDescription:@"testBlock is invoked."];
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        [self verifyRevokeRequest:request withToken:kAccessToken];
        NSData *data = [[NSData alloc] init];
        responseProvider(data, nil);
        [fetcherExpectation fulfill];
      };
  [_httpFetcher setTestBlock:testBlock];
  
  XCTestExpectation *completionExpectation =
      [self expectationWithDescription:@"Callback called with nil error"];
  [_signIn disconnectWithCompletion:^(NSError * _Nullable error) {
    XCTAssertNil(error);
    [completionExpectation fulfill];
  }];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertNil([_keychainHandler loadAuthState]);
}

// Verifies disconnect if access token is present.
- (void)testDisconnectNoCallback_accessTokenIsPresent {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(kAccessToken);
  
  XCTestExpectation *fetcherExpectation =
      [self expectationWithDescription:@"testBlock is invoked."];
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        [self verifyRevokeRequest:request withToken:kAccessToken];
        NSData *data = [[NSData alloc] init];
        responseProvider(data, nil);
        [fetcherExpectation fulfill];
      };
  [_httpFetcher setTestBlock:testBlock];
  
  [_signIn disconnectWithCompletion:nil];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertNil([_keychainHandler loadAuthState]);
}

// Verifies disconnect calls callback with no errors if refresh token is present.
- (void)testDisconnect_refreshTokenIsPresent {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(nil);
  OCMStub([_tokenResponse refreshToken]).andReturn(kRefreshToken);
  
  XCTestExpectation *fetcherExpectation =
      [self expectationWithDescription:@"testBlock is invoked."];
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        [self verifyRevokeRequest:request withToken:kRefreshToken];
        NSData *data = [[NSData alloc] init];
        responseProvider(data, nil);
        [fetcherExpectation fulfill];
      };
  [_httpFetcher setTestBlock:testBlock];
  
  XCTestExpectation *completionExpectation =
      [self expectationWithDescription:@"Callback called with nil error"];
  [_signIn disconnectWithCompletion:^(NSError * _Nullable error) {
    XCTAssertNil(error);
    [completionExpectation fulfill];
  }];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertNil([_keychainHandler loadAuthState]);
}

// Verifies disconnect errors are passed along to the callback.
- (void)testDisconnect_errors {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(kAccessToken);
  
  XCTestExpectation *fetcherExpectation =
      [self expectationWithDescription:@"testBlock is invoked."];
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        [self verifyRevokeRequest:request withToken:kAccessToken];
        NSError *error = [self error];
        responseProvider(nil, error);
        [fetcherExpectation fulfill];
      };
  [_httpFetcher setTestBlock:testBlock];
  
  XCTestExpectation *completionExpectation =
      [self expectationWithDescription:@"Callback called with an error"];
  [_signIn disconnectWithCompletion:^(NSError * _Nullable error) {
    XCTAssertNotNil(error);
    [completionExpectation fulfill];
  }];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertNotNil([_keychainHandler loadAuthState]);
}

// Verifies disconnect with errors
- (void)testDisconnectNoCallback_errors {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(kAccessToken);
  
  XCTestExpectation *fetcherExpectation =
      [self expectationWithDescription:@"testBlock is invoked."];
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        [self verifyRevokeRequest:request withToken:kAccessToken];
        NSError *error = [self error];
        responseProvider(nil, error);
        [fetcherExpectation fulfill];
      };
  [_httpFetcher setTestBlock:testBlock];
  
  [_signIn disconnectWithCompletion:nil];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertNotNil([_keychainHandler loadAuthState]);
}

// Verifies disconnect calls callback with no errors and clears keychain if no tokens are present.
- (void)testDisconnect_noTokens {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(nil);
  OCMStub([_tokenResponse refreshToken]).andReturn(nil);
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        XCTFail(@"_httpFetcher should not be invoked.");
      };
  [_httpFetcher setTestBlock:testBlock];
  
  XCTestExpectation *expectation =
      [self expectationWithDescription:@"Callback called with nil error"];
  [_signIn disconnectWithCompletion:^(NSError * _Nullable error) {
    XCTAssertNil(error);
    [expectation fulfill];
  }];
  [self waitForExpectationsWithTimeout:1 handler:nil];
  XCTAssertNil([_keychainHandler loadAuthState]);
}

// Verifies disconnect clears keychain if no tokens are present.
- (void)testDisconnectNoCallback_noTokens {
  [_keychainHandler saveAuthState:_authState];
  OCMStub([_authState lastTokenResponse]).andReturn(_tokenResponse);
  OCMStub([_tokenResponse accessToken]).andReturn(nil);
  OCMStub([_tokenResponse refreshToken]).andReturn(nil);
  GIDHTTPFetcherTestBlock testBlock =
      ^(NSURLRequest *request, GIDHTTPFetcherFakeResponseProviderBlock responseProvider) {
        XCTFail(@"_httpFetcher should not be invoked.");
      };
  [_httpFetcher setTestBlock:testBlock];
  
  [_signIn disconnectWithCompletion:nil];
  XCTAssertNil([_keychainHandler loadAuthState]);
}

- (void)testPresentingViewControllerException {
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
  _presentingViewController = nil;
#elif TARGET_OS_OSX
  _presentingWindow = nil;
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST


#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
  XCTAssertThrows([_signIn signInWithPresentingViewController:_presentingViewController
#elif TARGET_OS_OSX
  XCTAssertThrows([_signIn signInWithPresentingWindow:_presentingWindow
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST
                                                 hint:nil
                                           completion:_completion]);
}

- (void)testClientIDMissingException {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wnonnull"
  _signIn.configuration = [[GIDConfiguration alloc] initWithClientID:nil];
#pragma GCC diagnostic pop
  BOOL threw = NO;
  @try {
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
    [_signIn signInWithPresentingViewController:_presentingViewController
#elif TARGET_OS_OSX
    [_signIn signInWithPresentingWindow:_presentingWindow
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST
                             completion:nil];
  } @catch (NSException *exception) {
    threw = YES;
    XCTAssertEqualObjects(exception.description,
                          @"You must specify |clientID| in |GIDConfiguration|");
  } @finally {
  }
  XCTAssert(threw);
}

- (void)testSchemesNotSupportedException {
  [_fakeMainBundle fakeMissingAllSchemes];
  BOOL threw = NO;
  @try {
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
    [_signIn signInWithPresentingViewController:_presentingViewController
#elif TARGET_OS_OSX
    [_signIn signInWithPresentingWindow:_presentingWindow
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST
                                   hint:nil
                             completion:_completion];
  } @catch (NSException *exception) {
    threw = YES;
    XCTAssertEqualObjects(exception.description,
                          @"Your app is missing support for the following URL schemes: "
                          "fakeclientid");
  } @finally {
  }
  XCTAssert(threw);
}

#pragma mark - Restarting Authentication Tests

// Verifies that URL is not handled if there is no pending sign-in
- (void)testRequiringPendingSignIn {
  BOOL result = [_signIn handleURL:[NSURL URLWithString:kEMMRestartAuthURL]];
  XCTAssertFalse(result);
}

#pragma mark - EMM tests

#if TARGET_OS_IOS && !TARGET_OS_MACCATALYST

- (void)testAuthEndpointEMMError {
  if (!_isEligibleForEMM) {
    return;
  }

  id mockEMMErrorHandler = OCMStrictClassMock([GIDEMMErrorHandler class]);
  [[[mockEMMErrorHandler stub] andReturn:mockEMMErrorHandler] sharedInstance];
  __block void (^completion)(void);
  NSDictionary<NSString *, NSString *> *callbackParams = @{ @"error" : @"EMM Specific Error" };
  [[[mockEMMErrorHandler expect] andReturnValue:@YES]
      handleErrorFromResponse:callbackParams completion:SAVE_TO_ARG_BLOCK(completion)];

  [self OAuthLoginWithAddScopesFlow:NO
                          authError:callbackParams[@"error"]
                         tokenError:nil
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:NO
                     oldAccessToken:NO
                        modalCancel:NO];

  [mockEMMErrorHandler verify];
  [mockEMMErrorHandler stopMocking];
  completion();

  [self waitForExpectationsWithTimeout:1 handler:nil];

  XCTAssertTrue(_completionCalled, @"should call delegate");
  XCTAssertNotNil(_authError, @"should have error");
  XCTAssertEqualObjects(_authError.domain, kGIDSignInErrorDomain);
  XCTAssertEqual(_authError.code, kGIDSignInErrorCodeEMM);
  XCTAssertNil(_signIn.currentUser, @"should not have current user");
}

- (void)testTokenEndpointEMMError {
  if (!_isEligibleForEMM) {
    return;
  }

  __block void (^completion)(NSError *);
  NSDictionary *errorJSON = @{ @"error" : @"EMM Specific Error" };
  NSError *emmError = [NSError errorWithDomain:@"anydomain"
                                          code:12345
                                      userInfo:@{ OIDOAuthErrorFieldError : errorJSON }];
  id emmSupport = OCMStrictClassMock([GIDEMMSupport class]);
  [[emmSupport expect] handleTokenFetchEMMError:emmError
                                     completion:SAVE_TO_ARG_BLOCK(completion)];

  [self OAuthLoginWithAddScopesFlow:NO
                          authError:nil
                         tokenError:emmError
            emmPasscodeInfoRequired:NO
                      keychainError:NO
                     restoredSignIn:NO
                     oldAccessToken:NO
                        modalCancel:NO];

  NSError *handledError = [NSError errorWithDomain:kGIDSignInErrorDomain
                                              code:kGIDSignInErrorCodeEMM
                                          userInfo:emmError.userInfo];
  
  completion(handledError);

  [self waitForExpectationsWithTimeout:1 handler:nil];

  [emmSupport verify];
  XCTAssertTrue(_completionCalled, @"should call delegate");
  XCTAssertNotNil(_authError, @"should have error");
  XCTAssertEqualObjects(_authError.domain, kGIDSignInErrorDomain);
  XCTAssertEqual(_authError.code, kGIDSignInErrorCodeEMM);
  XCTAssertNil(_signIn.currentUser, @"should not have current user");
}

#endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST

#pragma mark - Helpers

- (NSError *)error {
  return [NSError errorWithDomain:kErrorDomain code:kErrorCode userInfo:nil];
}

- (void)verifyRevokeRequest:(NSURLRequest *)request withToken:(NSString *)token {
  NSURL *url = request.URL;
  XCTAssertEqualObjects([url scheme], @"https", @"scheme must match");
  XCTAssertEqualObjects([url host], @"accounts.google.com", @"host must match");
  XCTAssertEqualObjects([url path], @"/o/oauth2/revoke", @"path must match");
  OIDURLQueryComponent *queryComponent = [[OIDURLQueryComponent alloc] initWithURL:url];
  NSDictionary<NSString *, NSObject<NSCopying> *> *params = queryComponent.dictionaryValue;
  XCTAssertEqualObjects([params valueForKey:kSDKVersionLoggingParameter], GIDVersion(),
                        @"SDK version logging parameter should match");
  XCTAssertEqualObjects([params valueForKey:kEnvironmentLoggingParameter], GIDEnvironment(),
                        @"Environment logging parameter should match");

  NSData *body = request.HTTPBody;
  NSString* bodyString = [[NSString alloc] initWithData:body encoding:NSUTF8StringEncoding];
  NSArray<NSString *> *strings = [bodyString componentsSeparatedByString:@"="];
  XCTAssertEqualObjects(strings[1], token);
}

// The authorization flow with parameters to control which branches to take.
- (void)OAuthLoginWithAddScopesFlow:(BOOL)addScopesFlow
                          authError:(NSString *)authError
                         tokenError:(NSError *)tokenError
            emmPasscodeInfoRequired:(BOOL)emmPasscodeInfoRequired
                      keychainError:(BOOL)keychainError
                     restoredSignIn:(BOOL)restoredSignIn
                     oldAccessToken:(BOOL)oldAccessToken
                        modalCancel:(BOOL)modalCancel {
  if (restoredSignIn) {
    // clearAndAuthenticateWithOptions
    [_keychainHandler saveAuthState:_authState];
    BOOL isAuthorized = restoredSignIn ? YES : NO;
    [[[_authState expect] andReturnValue:[NSNumber numberWithBool:isAuthorized]] isAuthorized];
  }

  NSDictionary<NSString *, NSString *> *additionalParameters = emmPasscodeInfoRequired ?
      @{ @"emm_passcode_info_required" : @"1" } : nil;
  OIDAuthorizationResponse *authResponse =
      [OIDAuthorizationResponse testInstanceWithAdditionalParameters:additionalParameters
                                                         errorString:authError];

  OIDTokenResponse *tokenResponse =
      [OIDTokenResponse testInstanceWithIDToken:[OIDTokenResponse fatIDToken]
                                    accessToken:restoredSignIn ? kAccessToken : nil
                                      expiresIn:oldAccessToken ? @(300) : nil
                                   refreshToken:kRefreshToken
                                   tokenRequest:nil];

  OIDTokenRequest *tokenRequest = [[OIDTokenRequest alloc]
      initWithConfiguration:authResponse.request.configuration
                  grantType:OIDGrantTypeRefreshToken
          authorizationCode:nil
                redirectURL:nil
                   clientID:authResponse.request.clientID
               clientSecret:authResponse.request.clientSecret
                      scope:nil
               refreshToken:kRefreshToken
               codeVerifier:nil
       additionalParameters:tokenResponse.request.additionalParameters];
  
  // Set the response for the auth endpoint.
  GIDAuthorizationFlowProcessorTestBlock authorizationFlowTestBlock;
  if (modalCancel) {
    NSError *error = [NSError errorWithDomain:OIDGeneralErrorDomain
                                         code:OIDErrorCodeUserCanceledAuthorizationFlow
                                     userInfo:nil];
    authorizationFlowTestBlock =
        ^(GIDAuthorizationFlowProcessorFakeResponseProviderBlock responseProvider) {
      responseProvider(nil, error);
    };
  } else {
    authorizationFlowTestBlock =
        ^(GIDAuthorizationFlowProcessorFakeResponseProviderBlock responseProvider) {
      responseProvider(authResponse, nil);
    };
  }
  _authorizationFlowProcessor.testBlock = authorizationFlowTestBlock;
  
  // Set the response for `GIDProfileDataFetcher`.
  GIDProfileDataFetcherTestBlock profileDataFetcherTestBlock =
      ^(GIDProfileDataFetcherFakeResponseProvider responseProvider) {
    GIDProfileData *profileData = [GIDProfileData testInstance];
    responseProvider(profileData, nil);
  };
    
  _profileDataFetcher.testBlock = profileDataFetcherTestBlock;

  if (restoredSignIn) {
    // Mock `maybeFetchToken:` method in `restorePreviousSignIn:` flow.
    [[[_authState expect] andReturn:tokenResponse] lastTokenResponse];
    [[[_authState expect] andReturn:tokenResponse] lastTokenResponse];
    if (oldAccessToken) {
#if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
      // Corresponds to EMM support 
      [[[_authState expect] andReturn:authResponse] lastAuthorizationResponse];
#endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST
      [[[_authState expect] andReturn:tokenResponse] lastTokenResponse];
      [[[_authState expect] andReturn:tokenResponse] lastTokenResponse];
      [[[_authState expect] andReturn:tokenRequest]
          tokenRefreshRequestWithAdditionalParameters:[OCMArg any]];
    }
  } else {
    XCTestExpectation *expectation = [self expectationWithDescription:@"Callback called"];
    GIDSignInCompletion completion = ^(GIDSignInResult *_Nullable signInResult,
                                       NSError * _Nullable error) {
      [expectation fulfill];
      if (signInResult) {
        XCTAssertEqualObjects(signInResult.serverAuthCode, kServerAuthCode);
      } else {
        XCTAssertNotNil(error, @"Should have an error if the signInResult is nil");
      }
      XCTAssertFalse(self->_completionCalled, @"callback already called");
      self->_completionCalled = YES;
      self->_authError = error;
    };
    if (addScopesFlow) {
      [_signIn addScopes:@[kNewScope]
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
        presentingViewController:_presentingViewController
#elif TARGET_OS_OSX
        presentingWindow:_presentingWindow
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST
              completion:completion];
    } else {
      // Mock `maybeFetchToken:` method in Sign in flow.
      if (!(authError || modalCancel)) {
        [[[_authState expect] andReturn:nil] lastTokenResponse];
    #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
        // Corresponds to EMM support
        [[[_authState expect] andReturn:authResponse] lastAuthorizationResponse];
    #endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST
        [[[_authState expect] andReturn:nil] lastTokenResponse];
        [[[_authState expect] andReturn:authResponse] lastAuthorizationResponse];
        [[[_authState expect] andReturn:authResponse] lastAuthorizationResponse];
      }
      
#if TARGET_OS_IOS || TARGET_OS_MACCATALYST
      [_signIn signInWithPresentingViewController:_presentingViewController
#elif TARGET_OS_OSX
      [_signIn signInWithPresentingWindow:_presentingWindow
#endif // TARGET_OS_IOS || TARGET_OS_MACCATALYST
                                     hint:nil
                               completion:completion];
    }
    
    if (authError || modalCancel) {
      return;
    }
    
    [_authState verify];
  }

  if (restoredSignIn && oldAccessToken) {
    XCTestExpectation *expectation = [self expectationWithDescription:@"Callback should be called"];
    [_signIn restorePreviousSignInWithCompletion:^(GIDGoogleUser * _Nullable user,
                                                   NSError * _Nullable error) {
      [expectation fulfill];
      XCTAssertNil(error, @"should have no error");
    }];
  }

  if (!restoredSignIn || (restoredSignIn && oldAccessToken)) {
    XCTAssertNotNil(_savedTokenCallback);

    // OIDTokenCallback
    if (tokenError) {
      [[_authState expect] updateWithTokenResponse:nil error:tokenError];
    } else {
      [[_authState expect] updateWithTokenResponse:[OCMArg any] error:nil];
    }
  }

  if (tokenError) {
    _savedTokenCallback(nil, tokenError);
    return;
  }

  // SaveAuthCallback
  __block OIDAuthState *authState;
  __block OIDTokenResponse *updatedTokenResponse;
  __block OIDAuthorizationResponse *updatedAuthorizationResponse;
  __block GIDProfileData *profileData;

  if (keychainError) {
    _keychainHandler.failToSave = YES;
  } else {
    if (addScopesFlow) {
      [[[_authState expect] andReturn:authResponse] lastAuthorizationResponse];
      [[[_authState expect] andReturn:tokenResponse] lastTokenResponse];
      [[_user expect] updateWithTokenResponse:SAVE_TO_ARG_BLOCK(updatedTokenResponse)
                        authorizationResponse:SAVE_TO_ARG_BLOCK(updatedAuthorizationResponse)
                                  profileData:SAVE_TO_ARG_BLOCK(profileData)];
    } else {
      [[[_user stub] andReturn:_user] alloc];
      (void)[[[_user expect] andReturn:_user] initWithAuthState:SAVE_TO_ARG_BLOCK(authState)
                                                    profileData:SAVE_TO_ARG_BLOCK(profileData)];
    }
  }
  
  // CompletionCallback - mock server auth code parsing
  if (!keychainError) {
    [[[_authState expect] andReturn:tokenResponse] lastTokenResponse];
  }

  if (restoredSignIn && !oldAccessToken) {
    XCTestExpectation *expectation = [self expectationWithDescription:@"Callback should be called"];
    [_signIn restorePreviousSignInWithCompletion:^(GIDGoogleUser * _Nullable user,
                                                   NSError * _Nullable error) {
      [expectation fulfill];
      XCTAssertNil(error, @"should have no error");
    }];
  } else {
    // Simulate token endpoint response.
    _savedTokenCallback(tokenResponse, nil);
  }

  if (keychainError) {
    return;
  }
  [self waitForExpectationsWithTimeout:1 handler:nil];
  
  [_authState verify];
  
  if (addScopesFlow) {
    XCTAssertNotNil(updatedTokenResponse);
    XCTAssertNotNil(updatedAuthorizationResponse);
  } else {
    XCTAssertNotNil(authState);
  }
  // Check fat ID token decoding
  XCTAssertEqualObjects(profileData, [GIDProfileData testInstance]);

  // If attempt to authenticate again, will reuse existing auth object.
  _completionCalled = NO;
  _authError = nil;

  __block GIDGoogleUserCompletion completion;
  [[_user expect] refreshTokensIfNeededWithCompletion:SAVE_TO_ARG_BLOCK(completion)];

  XCTestExpectation *expectation = [self expectationWithDescription:@"Callback should be called"];

  [_signIn restorePreviousSignInWithCompletion:^(GIDGoogleUser * _Nullable user,
                                                 NSError * _Nullable error) {
    [expectation fulfill];
    XCTAssertNil(error, @"should have no error");
  }];

  completion(_user, nil);

  [self waitForExpectationsWithTimeout:1 handler:nil];
}

@end