feat: iOS apps receive autocompletion events

Author: dcalhoun

ios/Sources/GutenbergKit/Sources/EditorJSMessage.swift

@@ -37,6 +37,8 @@ struct EditorJSMessage {
         case showBlockPicker
         /// User requested the Media Library.
         case openMediaLibrary
+        /// The user triggered an autocompleter.
+        case onAutocompleterTriggered
     }
 
     struct DidUpdateBlocksBody: Decodable {
@@ -51,4 +53,8 @@ struct EditorJSMessage {
     struct DidUpdateFeaturedImageBody: Decodable {
         let mediaID: Int
     }
+
+    struct AutocompleterTriggeredBody: Decodable {
+        let type: String
+    }
 }

ios/Sources/GutenbergKit/Sources/EditorViewController.swift

@@ -326,6 +326,9 @@ public final class EditorViewController: UIViewController, GutenbergEditorContro
             case .openMediaLibrary:
                 let config = try message.decode(OpenMediaLibraryAction.self)
                 openMediaLibrary(config)
+            case .onAutocompleterTriggered:
+                let body = try message.decode(EditorJSMessage.AutocompleterTriggeredBody.self)
+                delegate?.editor(self, didTriggerAutocompleter: body.type)
             }
         } catch {
             fatalError("failed to decode message: \(error)")

ios/Sources/GutenbergKit/Sources/EditorViewControllerDelegate.swift

@@ -34,6 +34,11 @@ public protocol EditorViewControllerDelegate: AnyObject {
     func editor(_ viewController: EditorViewController, didLogException error: GutenbergJSException)
 
     func editor(_ viewController: EditorViewController, didRequestMediaFromSiteMediaLibrary config: OpenMediaLibraryAction)
+
+    /// Notifies the client that an autocompleter was triggered.
+    ///
+    /// - parameter type: The type of autocompleter that was triggered (e.g., "plus-symbol", "at-mention").
+    func editor(_ viewController: EditorViewController, didTriggerAutocompleter type: String)
 }
 
 public struct EditorState {