MBL-1158: Stub controller for logging in with OAuth (#1931)

* Move PKCETest.swift next to PKCE.swift

* MBL-1158: Add stub for presenting OAuth login controller when feature flag is enabled

* Change per review: unwrap window in presentationAnchor(for:)

Kickstarter-iOS/Features/LoginTout/Controller/LoginToutViewController.swift

@@ -400,8 +400,20 @@ public final class LoginToutViewController: UIViewController, MFMailComposeViewC
   }
 
   fileprivate func pushLoginViewController() {
-    self.navigationController?.pushViewController(LoginViewController.instantiate(), animated: true)
-    self.navigationItem.backBarButtonItem = UIBarButtonItem.back(nil, selector: nil)
+    if featureLoginWithOAuthEnabled() {
+      let session = ASWebAuthenticationSession(
+        url: OAuth.authorizationURL(),
+        callbackURLScheme: OAuth.redirectScheme
+      ) { _, _ in
+        // TODO: MBL-1159: Get required information from the callback; call mutation to login.
+      }
+
+      session.presentationContextProvider = self
+      session.start()
+    } else {
+      self.navigationController?.pushViewController(LoginViewController.instantiate(), animated: true)
+      self.navigationItem.backBarButtonItem = UIBarButtonItem.back(nil, selector: nil)
+    }
   }
 
   fileprivate func pushTwoFactorViewController(facebookAccessToken token: String) {
@@ -623,3 +635,15 @@ extension LoginToutViewController: ASAuthorizationControllerPresentationContextP
     return window
   }
 }
+
+// MARK: - ASWebAuthenticationPresentationContextProviding
+
+extension LoginToutViewController: ASWebAuthenticationPresentationContextProviding {
+  public func presentationAnchor(for _: ASWebAuthenticationSession) -> ASPresentationAnchor {
+    guard let window = self.view.window else {
+      return ASPresentationAnchor()
+    }
+
+    return window
+  }
+}

Kickstarter.xcodeproj/project.pbxproj

@@ -1488,6 +1488,7 @@
 		E10D06632ACF385E00470B5C /* FetchBackerProjectsQuery.json in Resources */ = {isa = PBXBuildFile; fileRef = E10D06622ACF385E00470B5C /* FetchBackerProjectsQuery.json */; };
 		E10D06652AD48C9C00470B5C /* FetchBackerProjectsQueryRequestForTests.graphql_test in Resources */ = {isa = PBXBuildFile; fileRef = E10D06642AD48C9C00470B5C /* FetchBackerProjectsQueryRequestForTests.graphql_test */; };
 		E10F75E82B6937FA00024AD1 /* PKCETest.swift in Sources */ = {isa = PBXBuildFile; fileRef = E1EEED2A2B686829009976D9 /* PKCETest.swift */; };
+		E11CFE4B2B6C42CE00497375 /* OAuth.swift in Sources */ = {isa = PBXBuildFile; fileRef = E11CFE492B6C41B400497375 /* OAuth.swift */; };
 		E170B9112B20E83B001BEDD7 /* MockGraphQLClient+CombineTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = E170B9102B20E83B001BEDD7 /* MockGraphQLClient+CombineTests.swift */; };
 		E1A1491E2ACDD76800F49709 /* FetchBackerProjectsQuery.graphql in Resources */ = {isa = PBXBuildFile; fileRef = E1A1491D2ACDD76700F49709 /* FetchBackerProjectsQuery.graphql */; };
 		E1A149202ACDD7BF00F49709 /* FetchProjectsEnvelope+FetchBackerProjectsQueryData.swift in Sources */ = {isa = PBXBuildFile; fileRef = E1A1491F2ACDD7BF00F49709 /* FetchProjectsEnvelope+FetchBackerProjectsQueryData.swift */; };
@@ -3056,6 +3057,7 @@
 		E10BE8E52B151CC800F73DC9 /* BlockUserInputTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BlockUserInputTests.swift; sourceTree = "<group>"; };
 		E10D06622ACF385E00470B5C /* FetchBackerProjectsQuery.json */ = {isa = PBXFileReference; lastKnownFileType = text.json; path = FetchBackerProjectsQuery.json; sourceTree = "<group>"; };
 		E10D06642AD48C9C00470B5C /* FetchBackerProjectsQueryRequestForTests.graphql_test */ = {isa = PBXFileReference; lastKnownFileType = text; path = FetchBackerProjectsQueryRequestForTests.graphql_test; sourceTree = "<group>"; };
+		E11CFE492B6C41B400497375 /* OAuth.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OAuth.swift; sourceTree = "<group>"; };
 		E170B9102B20E83B001BEDD7 /* MockGraphQLClient+CombineTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "MockGraphQLClient+CombineTests.swift"; sourceTree = "<group>"; };
 		E1889D8D2B6065D6004FBE21 /* CombineTestObserverTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CombineTestObserverTests.swift; sourceTree = "<group>"; };
 		E1A1491D2ACDD76700F49709 /* FetchBackerProjectsQuery.graphql */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text; path = FetchBackerProjectsQuery.graphql; sourceTree = "<group>"; };
@@ -3066,7 +3068,7 @@
 		E1BB25632B1E81AA000BD2D6 /* Publisher+Service.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Publisher+Service.swift"; sourceTree = "<group>"; };
 		E1EA34EE2AE1B28400942A04 /* Signal+Combine.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Signal+Combine.swift"; sourceTree = "<group>"; };
 		E1EEED282B684AA7009976D9 /* PKCE.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PKCE.swift; sourceTree = "<group>"; };
-		E1EEED2A2B686829009976D9 /* PKCETest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; name = PKCETest.swift; path = KsApi/PKCETest.swift; sourceTree = "<group>"; };
+		E1EEED2A2B686829009976D9 /* PKCETest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PKCETest.swift; sourceTree = "<group>"; };
 		E1FDB1E72AEAAC6100285F93 /* CombineTestObserver.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CombineTestObserver.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
@@ -5991,6 +5993,7 @@
 				A78537F71CB5803B00385B73 /* NSHTTPCookieStorageType.swift */,
 				37EB3E4B228CF4A400076E4C /* NumberFormatter.swift */,
 				37EB3E4D228CF4FB00076E4C /* NumberFormatterTests.swift */,
+				E11CFE492B6C41B400497375 /* OAuth.swift */,
 				94C92E7B2659EDBF00A96818 /* PaddingLabel.swift */,
 				A77D7B061CBAAF5D0077586B /* Paginate.swift */,
 				A7ED1F1C1E830FDC00BFFA01 /* PaginateTests.swift */,
@@ -6143,7 +6146,6 @@
 		A7E06C701C5A6EB300EBDCC2 = {
 			isa = PBXGroup;
 			children = (
-				E1EEED2A2B686829009976D9 /* PKCETest.swift */,
 				802800561C88F62500141235 /* Configs */,
 				E10BE8CE2B02975C00F73DC9 /* RichPushNotifications */,
 				A7E06DBC1C5C027800EBDCC2 /* Frameworks */,
@@ -6513,6 +6515,7 @@
 				D6C9A20D1F755FE200981E64 /* GraphSchemaTests.swift */,
 				D01587761EEB2ED6006E7684 /* MockService.swift */,
 				E1EEED282B684AA7009976D9 /* PKCE.swift */,
+				E1EEED2A2B686829009976D9 /* PKCETest.swift */,
 				D01588261EEB2ED7006E7684 /* ServerConfig.swift */,
 				D01588271EEB2ED7006E7684 /* Service.swift */,
 				E1BB25632B1E81AA000BD2D6 /* Publisher+Service.swift */,
@@ -7612,6 +7615,7 @@
 				064B007827A463D2007B21FE /* ImageViewElementCellViewModel.swift in Sources */,
 				A7F441E51D005A9400FE6FC5 /* SearchViewModel.swift in Sources */,
 				370F527A2254267900F159B9 /* UIApplicationType.swift in Sources */,
+				E11CFE4B2B6C42CE00497375 /* OAuth.swift in Sources */,
 				A75C81171D210BD700B5AD03 /* ShareViewModel.swift in Sources */,
 				6049D0202AA776B40015BB0D /* DesignSystemColors.swift in Sources */,
 				A757EAF01D1ABE7400A5C978 /* ActivitySurveyResponseCellViewModel.swift in Sources */,

Library/OAuth.swift

@@ -0,0 +1,12 @@
+import Foundation
+
+public struct OAuth {
+  public init() {}
+
+  public static let redirectScheme = "ksrauth2"
+  public static func authorizationURL() -> URL {
+    let base = AppEnvironment.current.apiService.serverConfig.webBaseUrl
+    // TODO: MBL-1159: This will take URL parameters, as defined in the ticket, for PKCE
+    return base
+  }
+}