Add init method with view model for the message list (#1046)

Author: martinmitrevski

Sources/StreamChatSwiftUI/ChatChannel/MessageList/MessageListView.swift

@@ -114,6 +114,49 @@ public struct MessageListView<Factory: ViewFactory>: View, KeyboardReadable {
             )
         }
     }
+    
+    public init(
+        factory: Factory = DefaultViewFactory.shared,
+        channel: ChatChannel,
+        viewModel: ChatChannelViewModel,
+        onLongPress: @escaping (MessageDisplayInfo) -> Void = { _ in }
+    ) {
+        self.init(
+            factory: factory,
+            channel: channel,
+            messages: viewModel.messages,
+            messagesGroupingInfo: viewModel.messagesGroupingInfo,
+            scrolledId: Binding(
+                get: { viewModel.scrolledId },
+                set: { viewModel.scrolledId = $0 }
+            ),
+            showScrollToLatestButton: Binding(
+                get: { viewModel.showScrollToLatestButton },
+                set: { viewModel.showScrollToLatestButton = $0 }
+            ),
+            quotedMessage: Binding(
+                get: { viewModel.quotedMessage },
+                set: { viewModel.quotedMessage = $0 }
+            ),
+            currentDateString: viewModel.currentDateString,
+            listId: viewModel.listId,
+            isMessageThread: viewModel.isMessageThread,
+            shouldShowTypingIndicator: viewModel.shouldShowTypingIndicator,
+            scrollPosition: Binding(
+                get: { viewModel.scrollPosition },
+                set: { viewModel.scrollPosition = $0 }
+            ),
+            loadingNextMessages: viewModel.loadingNextMessages,
+            firstUnreadMessageId: Binding(
+                get: { viewModel.firstUnreadMessageId },
+                set: { viewModel.firstUnreadMessageId = $0 }
+            ),
+            onMessageAppear: viewModel.handleMessageAppear(index:scrollDirection:),
+            onScrollToBottom: viewModel.scrollToLastMessage,
+            onLongPress: onLongPress,
+            onJumpToMessage: viewModel.jumpToMessage(messageId:)
+        )
+    }
 
     public var body: some View {
         ZStack {

StreamChatSwiftUITests/Tests/ChatChannel/MessageListView_Tests.swift

@@ -98,6 +98,40 @@ class MessageListView_Tests: StreamChatTestCase {
         assertSnapshot(matching: view, as: .image(perceptualPrecision: precision))
     }
 
+    // MARK: - Init with ChatChannelViewModel snapshot tests
+
+    func test_messageListView_viewModelInit_withReactions() {
+        // Given
+        let channel = ChatChannel.mockDMChannel(config: .init(reactionsEnabled: true))
+        let view = makeMessageListViewWithViewModel(channel: channel, messages: [.mock(id: .unique, cid: channel.cid, text: "Hello", author: .mock(id: .unique), reactionScores: [MessageReactionType(rawValue: "like"): 1])])
+            .applyDefaultSize()
+
+        // Then
+        assertSnapshot(matching: view, as: .image(perceptualPrecision: precision))
+    }
+
+    func test_messageListView_viewModelInit_noReactions() {
+        // Given
+        let channel = ChatChannel.mockDMChannel(config: .init(reactionsEnabled: false))
+        let view = makeMessageListViewWithViewModel(channel: channel, messages: [.mock(id: .unique, cid: channel.cid, text: "Hello", author: .mock(id: .unique))])
+            .applyDefaultSize()
+
+        // Then
+        assertSnapshot(matching: view, as: .image(perceptualPrecision: precision))
+    }
+
+    func test_messageListView_viewModelInit_unreadIndicator() {
+        // Given
+        var channel = ChatChannel.mockDMChannel()
+        // Set unread count on the channel
+        channel = ChatChannel.mockDMChannel(unreadCount: .mock(messages: 2))
+        let view = makeMessageListViewWithViewModel(channel: channel, messages: [.mock(id: .unique, cid: channel.cid, text: "Unread 1", author: .mock(id: .unique))])
+            .applyDefaultSize()
+
+        // Then
+        assertSnapshot(matching: view, as: .image(perceptualPrecision: precision))
+    }
+
     // MARK: - private
 
     func makeMessageListView(
@@ -138,4 +172,26 @@ class MessageListView_Tests: StreamChatTestCase {
 
         return messageListView
     }
+
+    private func makeMessageListViewWithViewModel(
+        channel: ChatChannel,
+        messages: [ChatMessage]
+    ) -> MessageListView<DefaultViewFactory> {
+        // Create a mock channel controller seeded with channel and messages
+        let controller = ChatChannelTestHelpers.makeChannelController(
+            chatClient: chatClient,
+            chatChannel: channel,
+            messages: messages
+        )
+
+        // Build the view model
+        let viewModel = ChatChannelViewModel(channelController: controller)
+
+        // Return the view using the new initializer
+        return MessageListView(
+            factory: DefaultViewFactory.shared,
+            channel: channel,
+            viewModel: viewModel
+        )
+    }
 }