feat: fix several view model issue (#13388)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

* **New Features**
* Error messages in chat cells are now clearly displayed with improved
formatting and dynamic height adjustment for better readability.
* Introduced the ability to remove specific chat cell view models from a
session.

* **Bug Fixes**
* Enhanced error handling to automatically remove invalid chat cell view
models when a message creation fails.

* **Other Improvements**
* Improved internal logic for handling message attachments and added
more detailed debug logging for the copilot response lifecycle.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/frontend/apps/ios/App/Packages/Intelligents/Sources/Intelligents/ChatManager/ChatManager+Stream.swift

@@ -160,6 +160,7 @@ private extension ChatManager {
     viewModelId: UUID
   ) {
     assert(!Thread.isMainThread)
+    print("[+] starting copilot response for session: \(sessionId)")
 
     let messageParameters: [String: AnyHashable] = [
       // packages/frontend/core/src/blocksuite/ai/provider/setup-provider.tsx
@@ -167,11 +168,11 @@ private extension ChatManager {
       "files": [String](), // attachment in context, keep nil for now
       "searchMode": editorData.isSearchEnabled ? "MUST" : "AUTO",
     ]
-    let hasMultipleAttachmentBlobs = [
+    let attachmentCount = [
       editorData.fileAttachments.count,
       editorData.documentAttachments.count,
-    ].reduce(0, +) > 1
-    let attachmentFieldName = hasMultipleAttachmentBlobs ? "options.blobs" : "options.blob"
+    ].reduce(0, +)
+    let attachmentFieldName = attachmentCount > 1 && attachmentCount != 0 ? "options.blobs" : "options.blob"
     let uploadableAttachments: [GraphQLFile] = [
       editorData.fileAttachments.map { file -> GraphQLFile in
         .init(fieldName: attachmentFieldName, originalName: file.name, data: file.data ?? .init())
@@ -183,8 +184,8 @@ private extension ChatManager {
     assert(uploadableAttachments.allSatisfy { !($0.data?.isEmpty ?? true) })
     guard let input = try? CreateChatMessageInput(
       attachments: [],
-      blob: hasMultipleAttachmentBlobs ? .none : "",
-      blobs: hasMultipleAttachmentBlobs ? .some([]) : .none,
+      blob: .none,
+      blobs: attachmentCount > 1 && attachmentCount != 0 ? .some([]) : .none,
       content: .some(contextSnippet.isEmpty ? editorData.text : "\(contextSnippet)\n\(editorData.text)"),
       params: .some(AffineGraphQL.JSON(_jsonValue: messageParameters)),
       sessionId: sessionId
@@ -195,11 +196,13 @@ private extension ChatManager {
     }
     let mutation = CreateCopilotMessageMutation(options: input)
     QLService.shared.client.upload(operation: mutation, files: uploadableAttachments) { result in
+      print("[*] createCopilotMessage result: \(result)")
       DispatchQueue.main.async {
         switch result {
         case let .success(graphQLResult):
           guard let messageIdentifier = graphQLResult.data?.createCopilotMessage else {
             self.report(sessionId, ChatError.invalidResponse)
+            self.delete(sessionId: sessionId, vmId: viewModelId)
             return
           }
           self.startStreamingResponse(
@@ -217,6 +220,7 @@ private extension ChatManager {
 
 private extension ChatManager {
   func startStreamingResponse(sessionId: String, messageId: String, applyingTo vmId: UUID) {
+    print("[+] starting streaming response for session: \(sessionId), message: \(messageId)")
     let base = IntelligentContext.shared.webViewMetadata[.currentServerBaseUrl] as? String
     guard let base, let url = URL(string: base) else {
       report(sessionId, ChatError.invalidServerConfiguration)

packages/frontend/apps/ios/App/Packages/Intelligents/Sources/Intelligents/ChatManager/ChatManager.swift

@@ -68,6 +68,10 @@ public class ChatManager: ObservableObject, @unchecked Sendable {
       }
     }
   }
+  
+  public func delete(sessionId: String, vmId: UUID) {
+    with(sessionId: sessionId) { $0.removeValue(forKey: vmId) }
+  }
 
   @discardableResult
   public func append(sessionId: String, _ viewModel: any ChatCellViewModel) -> UUID {

packages/frontend/apps/ios/App/Packages/Intelligents/Sources/Intelligents/Interface/View/ChatCell/ErrorCell.swift

@@ -11,24 +11,61 @@ import Then
 import UIKit
 
 class ErrorCell: ChatBaseCell {
+  let label = UILabel()
+  
   override func prepareContentView(inside contentView: UIView) {
     super.prepareContentView(inside: contentView)
+    contentView.addSubview(label)
   }
 
   override func prepareForReuse() {
     super.prepareForReuse()
+    label.attributedText = nil
   }
 
   override func layoutContentView(bounds: CGRect) {
     super.layoutContentView(bounds: bounds)
+    let width = bounds.width * 0.8
+    label.frame = .init(
+      x: (bounds.width - width) / 2,
+      y: 0,
+      width: width,
+      height: bounds.height
+    )
+  }
+  
+  override func configure(with viewModel: any ChatCellViewModel) {
+    super.configure(with: viewModel)
+    guard let vm = viewModel as? ErrorCellViewModel else {
+      assertionFailure("Invalid view model type")
+      return
+    }
+    label.attributedText = Self.attributeText(for: vm.errorMessage)
   }
 
+  static func attributeText(for text: String) -> NSAttributedString {
+    return .init(string: text, attributes: [
+      .font: UIFont.preferredFont(forTextStyle: .footnote),
+      .foregroundColor: UIColor.affineTextSecondary,
+      .paragraphStyle: NSMutableParagraphStyle().then {
+        $0.lineBreakMode = .byWordWrapping
+        $0.alignment = .center
+      }
+    ])
+  }
+  
   override class func heightForContent(
     for viewModel: any ChatCellViewModel,
     width: CGFloat
   ) -> CGFloat {
-    _ = viewModel
-    _ = width
-    return 0
+    let vm = viewModel as! ErrorCellViewModel
+    let text = Self.attributeText(for: vm.errorMessage)
+    let boundingRect = text.boundingRect(
+      with: CGSize(width: width * 0.8, height: .greatestFiniteMagnitude),
+      options: [.usesLineFragmentOrigin, .usesFontLeading],
+      context: nil
+    )
+    let boundingSize = boundingRect.size
+    return ceil(boundingSize.height)
   }
 }