Address review comments

AmplifyPlugins/Auth/Sources/AWSCognitoAuthPlugin/AWSCognitoAuthPlugin+Configure.swift

@@ -42,13 +42,13 @@ extension AWSCognitoAuthPlugin {
         let credentialsClient = CredentialStoreOperationClient(
             credentialStoreStateMachine: credentialStoreMachine)
 
-        let urlSessionClient = URLSessionClient(urlSession: makeURLSession())
+        let preInitiateAuthSignUpClient = AWSPreInitiateAuthSignUpBehavior(urlSession: makeURLSession())
 
         let authResolver = AuthState.Resolver().eraseToAnyResolver()
         let authEnvironment = makeAuthEnvironment(
             authConfiguration: authConfiguration,
             credentialsClient: credentialsClient,
-            urlSessionClient: urlSessionClient
+            preInitiateAuthSignUpClient: preInitiateAuthSignUpClient
         )
 
         let authStateMachine = StateMachine(resolver: authResolver, environment: authEnvironment)
@@ -158,7 +158,7 @@ extension AWSCognitoAuthPlugin {
     private func makeAuthEnvironment(
         authConfiguration: AuthConfiguration,
         credentialsClient: CredentialStoreStateBehavior,
-        urlSessionClient: URLSessionClientBehavior
+        preInitiateAuthSignUpClient: PreInitiateAuthSignUpBehavior
     ) -> AuthEnvironment {
 
         switch authConfiguration {
@@ -173,7 +173,7 @@ extension AWSCognitoAuthPlugin {
                 authenticationEnvironment: authenticationEnvironment,
                 authorizationEnvironment: nil,
                 credentialsClient: credentialsClient,
-                urlSessionClient: urlSessionClient,
+                preInitiateAuthSignUpClient: preInitiateAuthSignUpClient,
                 logger: log)
 
         case .identityPools(let identityPoolConfigurationData):
@@ -186,7 +186,7 @@ extension AWSCognitoAuthPlugin {
                 authenticationEnvironment: nil,
                 authorizationEnvironment: authorizationEnvironment,
                 credentialsClient: credentialsClient,
-                urlSessionClient: urlSessionClient,
+                preInitiateAuthSignUpClient: preInitiateAuthSignUpClient,
                 logger: log)
 
         case .userPoolsAndIdentityPools(let userPoolConfigurationData,
@@ -202,7 +202,7 @@ extension AWSCognitoAuthPlugin {
                 authenticationEnvironment: authenticationEnvironment,
                 authorizationEnvironment: authorizationEnvironment,
                 credentialsClient: credentialsClient,
-                urlSessionClient: urlSessionClient,
+                preInitiateAuthSignUpClient: preInitiateAuthSignUpClient,
                 logger: log)
         }
     }

AmplifyPlugins/Auth/Sources/AWSCognitoAuthPlugin/Environment/AuthEnvironment.swift

@@ -15,7 +15,7 @@ struct AuthEnvironment: Environment, LoggerProvider {
     let authenticationEnvironment: AuthenticationEnvironment?
     let authorizationEnvironment: AuthorizationEnvironment?
     let credentialsClient: CredentialStoreStateBehavior
-    let urlSessionClient: URLSessionClientBehavior?
+    let preInitiateAuthSignUpClient: PreInitiateAuthSignUpBehavior?
     let logger: Logger
 }
 

AmplifyPlugins/Auth/Sources/AWSCognitoAuthPlugin/Support/Passwordless/AWSPreInitiateAuthSignUpBehavior.swift

@@ -0,0 +1,79 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+import Amplify
+import AWSPluginsCore
+
+/// Concrete implementation of PreInitiateAuthSignUpBehavior
+class AWSPreInitiateAuthSignUpBehavior : PreInitiateAuthSignUpBehavior {
+
+    let urlSession: URLSession
+    let userAgent: String
+
+    init(urlSession: URLSession) {
+        self.urlSession = urlSession
+        self.userAgent = "\(AmplifyAWSServiceConfiguration.userAgentLib) \(AmplifyAWSServiceConfiguration.userAgentOS)"
+    }
+
+    func preInitiateAuthSignUp(preInitiateAuthSignUpEndpoint: URL,
+                               preInitiateAuthSignUpPayload: PreInitiateAuthSignUpPayload) async throws -> Result<Void, AuthError> {
+
+        var request = URLRequest(url: preInitiateAuthSignUpEndpoint)
+        request.httpMethod = "POST"
+        request.setValue(userAgent, forHTTPHeaderField: "User-Agent")
+
+        do {
+            let (_, response) = try await self.data(for: request)
+
+            guard let response = response as? HTTPURLResponse else {
+                throw AuthError.unknown("Response received is not a HTTPURLResponse")
+            }
+
+            if response.statusCode == 200 {
+                return .successfulVoid
+            } else {
+                throw AuthError.unknown("Response received with status code: \(response.statusCode)")
+            }
+        } catch {
+            throw AuthError.service(error.localizedDescription,
+                                    "API Gateway returned an error. Please check the error message for more details.",
+                                    error)
+        }
+    }
+
+    private func data(
+        for request: URLRequest,
+        delegate: (URLSessionTaskDelegate)? = nil)
+    async throws -> (Data, URLResponse) {
+        if #available(iOS 15.0, macOS 12.0, tvOS 15.0, *) {
+            return try await self.urlSession.data(
+                for: request,
+                delegate: delegate
+            )
+        } else {
+            // Fallback on earlier versions
+            return try await withCheckedThrowingContinuation({ continuation in
+                let dataTask = urlSession.dataTask(with: request) { data, response, error in
+                    if let data = data, let response = response {
+                        continuation.resume(returning: (data, response))
+                    } else {
+                        continuation.resume(throwing: error ?? AuthError.unknown(
+                                    """
+                                    An unknown error occurred with
+                                    data: \(String(describing: data))
+                                    response: \(String(describing: response))
+                                    error: \(String(describing: error))
+                                    """)
+                        )
+                    }
+                }
+                dataTask.resume()
+            })
+        }
+    }
+}

AmplifyPlugins/Auth/Sources/AWSCognitoAuthPlugin/Support/Passwordless/PreInitiateAuthSignUpBehavior.swift

@@ -0,0 +1,19 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+import Amplify
+
+// Protocol for initiating sign up in a passwordless flow
+protocol PreInitiateAuthSignUpBehavior {
+
+    func preInitiateAuthSignUp(
+        preInitiateAuthSignUpEndpoint: URL,
+        preInitiateAuthSignUpPayload: PreInitiateAuthSignUpPayload) 
+    async throws -> Result<Void, AuthError>
+
+}

AmplifyPlugins/Auth/Sources/AWSCognitoAuthPlugin/Support/URLSessionClient/PreInitiateAuthPayload.swift → AmplifyPlugins/Auth/Sources/AWSCognitoAuthPlugin/Support/Passwordless/PreInitiateAuthSignUpPayload.swift

@@ -9,7 +9,7 @@ import Foundation
 
 // Payload data structure to send to the API Gateway endpoint
 // for password sign up and sign in flow to initiate creating a new user
-struct PreInitiateAuthPayload: Codable {
+struct PreInitiateAuthSignUpPayload: Codable {
     let username: String
     let deliveryMedium: String
     let userAttributes: [String:String]?

AmplifyPlugins/Auth/Tests/AWSCognitoAuthPluginUnitTests/Mocks/MockPreInitiateAuthSignUpBehavior.swift

@@ -0,0 +1,24 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Foundation
+import Amplify
+@testable import AWSPluginsCore
+@testable import AWSCognitoAuthPlugin
+
+class MockPreInitiateAuthSignUpBehavior: PreInitiateAuthSignUpBehavior {
+
+    public var preInitiateAuthSignUpCallCount = 0
+
+    func preInitiateAuthSignUp(
+        preInitiateAuthSignUpEndpoint: URL,
+        preInitiateAuthSignUpPayload: PreInitiateAuthSignUpPayload)
+    async throws -> Result<Void, AuthError> {
+        preInitiateAuthSignUpCallCount += 1
+        return .successfulVoid
+    }
+}

AmplifyPlugins/Auth/Tests/AWSCognitoAuthPluginUnitTests/Support/DefaultConfig.swift

@@ -168,7 +168,7 @@ enum Defaults {
             authenticationEnvironment: authenticationEnvironment,
             authorizationEnvironment: authZEnvironment ?? authorizationEnvironment,
             credentialsClient: makeCredentialStoreOperationBehavior(),
-            urlSessionClient: URLSessionClient(urlSession: makeURLSession()),
+            preInitiateAuthSignUpClient: AWSPreInitiateAuthSignUpBehavior(urlSession: makeURLSession()),
             logger: Amplify.Logging.logger(forCategory: "awsCognitoAuthPluginTest")
         )
         Amplify.Logging.logLevel = .verbose

AmplifyPlugins/Auth/Tests/AWSCognitoAuthPluginUnitTests/TaskTests/ClientBehaviorTests/SignIn/AWSAuthConfirmSignInTaskTests.swift

@@ -494,7 +494,7 @@ class AuthenticationProviderConfirmSigninTests: BasePluginTest {
             authenticationEnvironment: nil,
             authorizationEnvironment: authorizationEnvironment,
             credentialsClient: Defaults.makeCredentialStoreOperationBehavior(),
-            urlSessionClient: nil,
+            preInitiateAuthSignUpClient: nil,
             logger: Amplify.Logging.logger(forCategory: "awsCognitoAuthPluginTest")
         )
         let stateMachine = Defaults.authStateMachineWith(environment: environment,

AmplifyPlugins/Auth/Tests/AWSCognitoAuthPluginUnitTests/TaskTests/ClientBehaviorTests/SignIn/ConfirmSignInTOTPTaskTests.swift

@@ -512,7 +512,7 @@ class ConfirmSignInTOTPTaskTests: BasePluginTest {
             authenticationEnvironment: nil,
             authorizationEnvironment: authorizationEnvironment,
             credentialsClient: Defaults.makeCredentialStoreOperationBehavior(),
-            urlSessionClient: nil,
+            preInitiateAuthSignUpClient: nil,
             logger: Amplify.Logging.logger(forCategory: "awsCognitoAuthPluginTest")
         )
         let stateMachine = Defaults.authStateMachineWith(environment: environment,

AmplifyPlugins/Auth/Tests/AWSCognitoAuthPluginUnitTests/TaskTests/ClientBehaviorTests/SignIn/ConfirmSignInWithMFASelectionTaskTests.swift

@@ -548,7 +548,7 @@ class ConfirmSignInWithMFASelectionTaskTests: BasePluginTest {
             authenticationEnvironment: nil,
             authorizationEnvironment: authorizationEnvironment,
             credentialsClient: Defaults.makeCredentialStoreOperationBehavior(),
-            urlSessionClient: nil,
+            preInitiateAuthSignUpClient: nil,
             logger: Amplify.Logging.logger(forCategory: "awsCognitoAuthPluginTest")
         )
         let stateMachine = Defaults.authStateMachineWith(environment: environment,

AmplifyPlugins/Auth/Tests/AWSCognitoAuthPluginUnitTests/TaskTests/ClientBehaviorTests/SignIn/ConfirmSignInWithSetUpMFATaskTests.swift

@@ -311,7 +311,7 @@ class ConfirmSignInWithSetUpMFATaskTests: BasePluginTest {
             authenticationEnvironment: nil,
             authorizationEnvironment: authorizationEnvironment,
             credentialsClient: Defaults.makeCredentialStoreOperationBehavior(),
-            urlSessionClient: nil,
+            preInitiateAuthSignUpClient: nil,
             logger: Amplify.Logging.logger(forCategory: "awsCognitoAuthPluginTest")
         )
         let stateMachine = Defaults.authStateMachineWith(environment: environment,