Adding docs

Author: ssathy2

IFTTT SDK/WebServiceAuthentication.swift

@@ -7,10 +7,14 @@
 
 import AuthenticationServices
 
-/// Describes the error reason for a failed `AuthenticationSession`
+/// Describes the error reason for a failed `WebServiceAuthentication`
 ///
-/// - userCanceled: The user cancelled the authentication session
-/// - 
+/// - userCanceled: The user cancelled the authentication session.
+/// - failed: The authentication failed for some reason.
+/// - invalidResponse: The response returned by the web service was invalid.
+/// - notHandled: The error wasn't handled by the web service.
+/// - presentationContextInvalid: The presentation content provided was invalid.
+/// - unknown: Some unknown error ocurred when authenticating with the web service.
 enum AuthenticationError: Error {
     case userCanceled
     case failed
@@ -20,18 +24,42 @@ enum AuthenticationError: Error {
     case unknown
 }
 
+/// Describes a generic method of authenticating with a service
 protocol ServiceAuthentication {
+    /// The parameters to pass to authenticate with the service
     associatedtype Parameters
+    /// The object type on a successful service authentication
     associatedtype Completion
+    /// THe error type on a non-successful service authentication
     associatedtype ErrorType: Error
 
+    /// Describes a closure that gets invoked on success/failure of a service authentication
     typealias AuthenticationSessionClosure = ((Result<Completion, ErrorType>) -> Void)
 
+    /// Starts the service authentication.
+    /// - Parameters:
+    ///     - parameters: An instance of `Parameters` which can be used in authenticating against the service.
+    ///     - completionHandler: The closure to invoke on a success or failure response from the service.
+    /// - Returns: A `Bool` value as to whether or not the service authentication was started or not.
     func start(with parameters: Parameters, completionHandler: @escaping AuthenticationSessionClosure) -> Bool
+    
+    /// Cancels the service authentication.
     func cancel()
 }
 
+/// A basic OAuth web service authentication object.
 class WebServiceAuthentication: ServiceAuthentication {
+    
+    /// The parameters used when authenticating against a web service
+    struct WebServiceAuthenticationParameters {
+        /// The URL to use in authenticating the service
+        let url: URL
+        /// The callback url scheme which the service uses to pass back any data
+        let callbackURLScheme: String?
+        /// Determines whether or not the session should be ephemeral or not. Not all service authentication types support this
+        let prefersEphemeralWebBrowserSession: Bool
+    }
+
     typealias Parameters = WebServiceAuthenticationParameters
     typealias Completion = URL
     typealias ErrorType = AuthenticationError
@@ -46,8 +74,3 @@ class WebServiceAuthentication: ServiceAuthentication {
     }
 }
 
-struct WebServiceAuthenticationParameters {
-    let url: URL
-    let callbackURLScheme: String?
-    let prefersEphemeralWebBrowserSession: Bool
-}