chore: get WebView for inline message and add to Inline View to display

Part of: https://linear.app/customerio/issue/MBL-310/create-a-uikit-uiview-that-displays-an-inline-in-app-message-sent-from

Create a WebView to display inline in-app message and display in the Inline UIView. To do this, we can re-use a lot of the same logic that Modal messages use to create WebViews and display them.

Testing:
There are some automated tests added in this commit.

Reviewer notes:
This commit will not show an in-app message if you were to add it to a sample app. Autolayout constraints need to be added to have Views resize and that will come in a future commit.

commit-id:025c7bf5

Sources/MessagingInApp/Gist/Gist.swift

@@ -3,13 +3,14 @@ import Foundation
 import UIKit
 
 protocol GistInstance: AutoMockable {
+    var siteId: String { get }
     func showMessage(_ message: Message, position: MessagePosition) -> Bool
 }
 
 public class Gist: GistInstance, GistDelegate {
     var messageQueueManager: MessageQueueManager = DIGraphShared.shared.messageQueueManager
     var shownMessageQueueIds: Set<String> = []
-    private var messageManagers: [MessageManager] = []
+    private var messageManagers: [ModalMessageManager] = []
     public var siteId: String = ""
     public var dataCenter: String = ""
 
@@ -137,8 +138,8 @@ public class Gist: GistInstance, GistDelegate {
 
     // Message Manager
 
-    private func createMessageManager(siteId: String, message: Message) -> MessageManager {
-        let messageManager = MessageManager(siteId: siteId, message: message)
+    private func createMessageManager(siteId: String, message: Message) -> ModalMessageManager {
+        let messageManager = ModalMessageManager(siteId: siteId, message: message)
         messageManager.delegate = self
         messageManagers.append(messageManager)
         return messageManager

Sources/MessagingInApp/Gist/Managers/MessageManager.swift

@@ -5,12 +5,81 @@ public enum GistMessageActions: String {
     case close = "gist://close"
 }
 
+/**
+ Class that implements the business logic for a inline message being displayed.
+ */
+class InlineMessageManager: MessageManager {}
+
+/**
+ Class that implements the business logic for a modal message being displayed.
+ */
+class ModalMessageManager: MessageManager {
+    private var messageLoaded = false
+    private var modalViewManager: ModalViewManager?
+    var messagePosition: MessagePosition = .top
+
+    override func routeLoaded(route: String) {
+        super.routeLoaded(route: route)
+
+        if route == currentMessage.messageId, !messageLoaded {
+            messageLoaded = true
+            if isMessageEmbed {
+                delegate?.messageShown(message: currentMessage)
+            } else {
+                if UIApplication.shared.applicationState == .active {
+                    loadModalMessage()
+                } else {
+                    Gist.shared.removeMessageManager(instanceId: currentMessage.instanceId)
+                }
+            }
+        }
+    }
+
+    func showMessage(position: MessagePosition) {
+        loadingMessage()
+        messagePosition = position
+    }
+
+    override func dismissMessage(completionHandler: (() -> Void)? = nil) {
+        if let modalViewManager = modalViewManager {
+            modalViewManager.dismissModalView { [weak self] in
+                guard let self = self else { return }
+                self.delegate?.messageDismissed(message: self.currentMessage)
+                completionHandler?()
+            }
+        }
+    }
+
+    private func loadModalMessage() {
+        if messageLoaded {
+            modalViewManager = ModalViewManager(gistView: gistView, position: messagePosition)
+            modalViewManager?.showModalView { [weak self] in
+                guard let self = self else { return }
+                self.delegate?.messageShown(message: self.currentMessage)
+                self.doneLoadingMessage()
+            }
+        }
+    }
+}
+
+/**
+ Class that handles a lot of the business logic for modal and inline in-app messages.
+
+ This class is meant to be extended and not constructed directly. It holds the common logic between all in-app message types.
+
+ Usage:
+ * When you have a Message that should be displayed, create a new instance of manager. You create 1 manager instance per 1 in-app message to display:
+ ```
+ // Keep a strong reference to manager instance.
+ let messageManager = MessageManager(siteId: Gist.shared.siteId, message: message)
+ ```
+ * Get the WebView instance that displays the in-app message: `messageManager.gistView`
+ * Set the delegate to listen for events from the WebView: `messageManager.gistView.delegate = self`
+ * Display the WebView in your view: `addSubview(messageManager.gistView)`
+ */
 class MessageManager: EngineWebDelegate {
     private var engine: EngineWeb?
     private let siteId: String
-    private var messagePosition: MessagePosition = .top
-    private var messageLoaded = false
-    private var modalViewManager: ModalViewManager?
     var isMessageEmbed = false
     let currentMessage: Message
     var gistView: GistView!
@@ -39,35 +108,21 @@ class MessageManager: EngineWebDelegate {
         }
     }
 
-    func showMessage(position: MessagePosition) {
-        elapsedTimer.start(title: "Displaying modal for message: \(currentMessage.messageId)")
-        messagePosition = position
+    func loadingMessage() {
+        elapsedTimer.start(title: "Loading message with id: \(currentMessage.messageId)")
+    }
+
+    func doneLoadingMessage() {
+        elapsedTimer.end()
     }
 
     func getMessageView() -> GistView {
         isMessageEmbed = true
         return gistView
     }
 
-    private func loadModalMessage() {
-        if messageLoaded {
-            modalViewManager = ModalViewManager(gistView: gistView, position: messagePosition)
-            modalViewManager?.showModalView { [weak self] in
-                guard let self = self else { return }
-                self.delegate?.messageShown(message: self.currentMessage)
-                self.elapsedTimer.end()
-            }
-        }
-    }
-
     func dismissMessage(completionHandler: (() -> Void)? = nil) {
-        if let modalViewManager = modalViewManager {
-            modalViewManager.dismissModalView { [weak self] in
-                guard let self = self else { return }
-                self.delegate?.messageDismissed(message: self.currentMessage)
-                completionHandler?()
-            }
-        }
+        // expect subclass implements this.
     }
 
     func removePersistentMessage() {
@@ -208,18 +263,6 @@ class MessageManager: EngineWebDelegate {
         Logger.instance.info(message: "Message loaded with route: \(route)")
 
         currentRoute = route
-        if route == currentMessage.messageId, !messageLoaded {
-            messageLoaded = true
-            if isMessageEmbed {
-                delegate?.messageShown(message: currentMessage)
-            } else {
-                if UIApplication.shared.applicationState == .active {
-                    loadModalMessage()
-                } else {
-                    Gist.shared.removeMessageManager(instanceId: currentMessage.instanceId)
-                }
-            }
-        }
     }
 
     deinit {

Sources/MessagingInApp/Views/InAppMessageView.swift

@@ -23,13 +23,19 @@ public class InAppMessageView: UIView {
         DIGraphShared.shared.messageQueueManager
     }
 
+    private var gist: GistInstance {
+        DIGraphShared.shared.gist
+    }
+
     // Can set in the constructor or can set later (like if you use Storyboards)
     public var elementId: String? {
         didSet {
             checkIfMessageAvailableToDisplay()
         }
     }
 
+    private var inlineMessageManager: InlineMessageManager?
+
     public init(elementId: String) {
         super.init(frame: .zero)
         self.elementId = elementId
@@ -65,5 +71,30 @@ public class InAppMessageView: UIView {
         //      }
     }
 
-    private func displayInAppMessage(_ message: Message) {}
+    private func displayInAppMessage(_ message: Message) {
+        // There might already be a message displayed. If so, remove it and cleanup the resources.
+        // First, remove the subview that the inline manager has a reference to.
+        // Lastly, cleanup the inline manager.
+        subviews.first?.removeFromSuperview()
+        inlineMessageManager = nil
+
+        // Create a new manager for this new message to display and then display the manager's WebView.
+        let newInlineMessageManager = InlineMessageManager(siteId: gist.siteId, message: message)
+
+        guard let webView = newInlineMessageManager.gistView else {
+            return // we dont expect this to happen, but better to handle it gracefully instead of force unwrapping
+        }
+
+        webView.delegate = self
+        addSubview(webView)
+
+        inlineMessageManager = newInlineMessageManager
+    }
+}
+
+extension InAppMessageView: GistViewDelegate {
+    // This function is called by WebView when the content's size changes.
+    public func sizeChanged(message: Message, width: CGFloat, height: CGFloat) {}
+
+    public func action(message: Message, currentRoute: String, action: String, name: String) {}
 }

Sources/MessagingInApp/autogenerated/AutoMockable.generated.swift

@@ -95,7 +95,45 @@ class GistInstanceMock: GistInstance, Mock {
         Mocks.shared.add(mock: self)
     }
 
+    /**
+     When setter of the property called, the value given to setter is set here.
+     When the getter of the property called, the value set here will be returned. Your chance to mock the property.
+     */
+    var underlyingSiteId: String!
+    /// `true` if the getter or setter of property is called at least once.
+    var siteIdCalled: Bool {
+        siteIdGetCalled || siteIdSetCalled
+    }
+
+    /// `true` if the getter called on the property at least once.
+    var siteIdGetCalled: Bool {
+        siteIdGetCallsCount > 0
+    }
+
+    var siteIdGetCallsCount = 0
+    /// `true` if the setter called on the property at least once.
+    var siteIdSetCalled: Bool {
+        siteIdSetCallsCount > 0
+    }
+
+    var siteIdSetCallsCount = 0
+    /// The mocked property with a getter and setter.
+    var siteId: String {
+        get {
+            mockCalled = true
+            siteIdGetCallsCount += 1
+            return underlyingSiteId
+        }
+        set(value) {
+            mockCalled = true
+            siteIdSetCallsCount += 1
+            underlyingSiteId = value
+        }
+    }
+
     public func resetMock() {
+        siteIdGetCallsCount = 0
+        siteIdSetCallsCount = 0
         showMessageCallsCount = 0
         showMessageReceivedArguments = nil
         showMessageReceivedInvocations = []

Tests/MessagingInApp/Views/InAppMessageViewTest.swift

@@ -43,4 +43,37 @@ class InAppMessageViewTest: UnitTest {
         let actualElementId = queueMock.getInlineMessagesReceivedArguments
         XCTAssertEqual(actualElementId, givenElementId)
     }
+
+    // MARK: Display in-app message
+
+    func test_displayInAppMessage_givenNoMessageAvailable_expectDoNotDisplayAMessage() {
+        queueMock.getInlineMessagesReturnValue = []
+
+        let inlineView = InAppMessageView(elementId: .random)
+
+        XCTAssertNil(getInAppMessageWebView(fromInlineView: inlineView))
+    }
+
+    func test_displayInAppMessage_givenMessageAvailable_expectDisplayMessage() {
+        let givenInlineMessage = Message.randomInline
+        queueMock.getInlineMessagesReturnValue = [givenInlineMessage]
+
+        let inlineView = InAppMessageView(elementId: givenInlineMessage.elementId!)
+
+        XCTAssertNotNil(getInAppMessageWebView(fromInlineView: inlineView))
+    }
+}
+
+extension InAppMessageViewTest {
+    func getInAppMessageWebView(fromInlineView view: InAppMessageView) -> GistView? {
+        let gistViews: [GistView] = view.subviews.filter { $0 is GistView }.map { $0 as! GistView }
+
+        if gistViews.isEmpty {
+            return nil
+        }
+
+        XCTAssertEqual(gistViews.count, 1)
+
+        return gistViews.first
+    }
 }