Fix message completion trigger to work anywhere in the message

ElementX/Sources/Screens/MediaUploadPreviewScreen/MediaUploadPreviewScreenModels.swift

@@ -23,6 +23,7 @@ struct MediaUploadPreviewScreenViewState: BindableState {
 struct MediaUploadPreviewScreenBindings: BindableState {
     var caption = NSAttributedString()
     var presendCallback: (() -> Void)?
+    var selectedRange = NSRange(location: 0, length: 0)
 
     var isPresentingMediaCaptionWarning = false
 }

ElementX/Sources/Screens/MediaUploadPreviewScreen/View/MediaUploadPreviewScreen.swift

@@ -60,6 +60,7 @@ struct MediaUploadPreviewScreen: View {
                 MessageComposerTextField(placeholder: L10n.richTextEditorComposerCaptionPlaceholder,
                                          text: $context.caption,
                                          presendCallback: $context.presendCallback,
+                                         selectedRange: $context.selectedRange,
                                          maxHeight: ComposerConstant.maxHeight,
                                          keyHandler: handleKeyPress) { _ in }
                     .focused($isComposerFocussed)

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/CompletionSuggestionService.swift

@@ -73,8 +73,8 @@ final class CompletionSuggestionService: CompletionSuggestionServiceProtocol {
         }
     }
 
-    func processTextMessage(_ textMessage: String?) {
-        setSuggestionTrigger(detectTriggerInText(textMessage))
+    func processTextMessage(_ textMessage: String?, selectedRange: NSRange?) {
+        setSuggestionTrigger(detectTriggerInText(text: textMessage, selectedRange: selectedRange))
     }
 
     func setSuggestionTrigger(_ suggestionTrigger: SuggestionTrigger?) {
@@ -83,23 +83,46 @@ final class CompletionSuggestionService: CompletionSuggestionServiceProtocol {
 
     // MARK: - Private
 
-    private func detectTriggerInText(_ text: String?) -> SuggestionTrigger? {
-        guard let text else {
+    private func detectTriggerInText(text: String?, selectedRange: NSRange?) -> SuggestionTrigger? {
+        guard let text, let selectedRange else {
             return nil
         }
 
-        let components = text.components(separatedBy: .whitespaces)
+        var suggestionText: String?
+        var range: Range<String.Index>?
 
-        guard var lastComponent = components.last,
-              let range = text.range(of: lastComponent, options: .backwards),
-              lastComponent.count > 0,
-              let suggestionKey = SuggestionTriggerPattern(rawValue: lastComponent.removeFirst()),
-              // If a second character exists and is the same as the key it shouldn't trigger.
-              lastComponent.first != suggestionKey.rawValue else {
-            return nil
+        var startIndex: String.Index = text.startIndex
+        let components = text
+            .components(separatedBy: .whitespaces)
+            .filter { $0.first == SuggestionTriggerPattern.at.rawValue }
+
+        for component in components {
+            guard let textRange = text.range(of: component, range: startIndex..<text.endIndex) else {
+                continue
+            }
+            startIndex = textRange.upperBound
+
+            let startIndex = textRange.lowerBound.utf16Offset(in: text)
+            let endIndex = textRange.upperBound.utf16Offset(in: text)
+
+            guard selectedRange.location >= startIndex,
+                  selectedRange.location <= endIndex,
+                  selectedRange.length <= endIndex - startIndex
+            else {
+                continue
+            }
+
+            suggestionText = String(text[textRange.lowerBound..<textRange.upperBound])
+            suggestionText?.removeFirst()
+            range = textRange
         }
 
-        return .init(type: .user, text: lastComponent, range: NSRange(range, in: text))
+        guard let suggestionText,
+              let range else {
+            return nil
+        }
+
+        return .init(type: .user, text: suggestionText, range: NSRange(range, in: text))
     }
 
     private static func shouldIncludeMember(userID: String, displayName: String?, searchText: String) -> Bool {

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/CompletionSuggestionServiceProtocol.swift

@@ -51,7 +51,7 @@ struct MentionSuggestionItem: Identifiable, Equatable {
 protocol CompletionSuggestionServiceProtocol {
     var suggestionsPublisher: AnyPublisher<[SuggestionItem], Never> { get }
 
-    func processTextMessage(_ textMessage: String?)
+    func processTextMessage(_ textMessage: String?, selectedRange: NSRange?)
 
     func setSuggestionTrigger(_ suggestionTrigger: SuggestionTrigger?)
 }

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/ComposerToolbarModels.swift

@@ -53,6 +53,7 @@ enum ComposerToolbarViewAction {
 
     case plainComposerTextChanged
     case didToggleFormattingOptions
+    case selectedTextChanged
 }
 
 enum ComposerAttachmentType {
@@ -131,6 +132,7 @@ struct ComposerToolbarViewStateBindings {
     var composerExpanded = false
     var formatItems: [FormatItem] = .init()
     var alertInfo: AlertInfo<UUID>?
+    var selectedRange = NSRange(location: 0, length: 0)
 
     var presendCallback: (() -> Void)?
 }

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/ComposerToolbarViewModel.swift

@@ -197,7 +197,9 @@ final class ComposerToolbarViewModel: ComposerToolbarViewModelType, ComposerTool
         case .voiceMessage(let voiceMessageAction):
             processVoiceMessageAction(voiceMessageAction)
         case .plainComposerTextChanged:
-            completionSuggestionService.processTextMessage(state.bindings.plainComposerText.string)
+            completionSuggestionService.processTextMessage(state.bindings.plainComposerText.string, selectedRange: context.viewState.bindings.selectedRange)
+        case .selectedTextChanged:
+            completionSuggestionService.processTextMessage(state.bindings.plainComposerText.string, selectedRange: context.viewState.bindings.selectedRange)
         case .didToggleFormattingOptions:
             if context.composerFormattingEnabled {
                 guard !context.plainComposerText.string.isEmpty else {

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/View/ComposerToolbar.swift

@@ -154,6 +154,7 @@ struct ComposerToolbar: View {
     private var messageComposer: some View {
         MessageComposer(plainComposerText: $context.plainComposerText,
                         presendCallback: $context.presendCallback,
+                        selectedRange: $context.selectedRange,
                         composerView: composerView,
                         mode: context.viewState.composerMode,
                         composerFormattingEnabled: context.composerFormattingEnabled,
@@ -199,6 +200,9 @@ struct ComposerToolbar: View {
         .onChange(of: context.composerFormattingEnabled) {
             context.send(viewAction: .didToggleFormattingOptions)
         }
+        .onChange(of: context.selectedRange) {
+            context.send(viewAction: .selectedTextChanged)
+        }
         .onAppear {
             composerFocused = context.composerFocused
         }

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/View/MessageComposer.swift

@@ -15,6 +15,7 @@ typealias PasteHandler = (NSItemProvider) -> Void
 struct MessageComposer: View {
     @Binding var plainComposerText: NSAttributedString
     @Binding var presendCallback: (() -> Void)?
+    @Binding var selectedRange: NSRange
     let composerView: WysiwygComposerView
     let mode: ComposerMode
     let composerFormattingEnabled: Bool
@@ -66,6 +67,7 @@ struct MessageComposer: View {
             MessageComposerTextField(placeholder: L10n.richTextEditorComposerPlaceholder,
                                      text: $plainComposerText,
                                      presendCallback: $presendCallback,
+                                     selectedRange: $selectedRange,
                                      maxHeight: ComposerConstant.maxHeight,
                                      keyHandler: { handleKeyPress($0) },
                                      pasteHandler: pasteAction)
@@ -285,6 +287,7 @@ struct MessageComposer_Previews: PreviewProvider, TestablePreview {
 
         return MessageComposer(plainComposerText: .constant(content),
                                presendCallback: .constant(nil),
+                               selectedRange: .constant(NSRange(location: 0, length: 0)),
                                composerView: composerView,
                                mode: mode,
                                composerFormattingEnabled: false,

ElementX/Sources/Screens/RoomScreen/ComposerToolbar/View/MessageComposerTextField.swift

@@ -12,6 +12,7 @@ struct MessageComposerTextField: View {
     let placeholder: String
     @Binding var text: NSAttributedString
     @Binding var presendCallback: (() -> Void)?
+    @Binding var selectedRange: NSRange
 
     let maxHeight: CGFloat
     let keyHandler: GenericKeyHandler
@@ -20,6 +21,7 @@ struct MessageComposerTextField: View {
     var body: some View {
         UITextViewWrapper(text: $text,
                           presendCallback: $presendCallback,
+                          selectedRange: $selectedRange,
                           maxHeight: maxHeight,
                           keyHandler: keyHandler,
                           pasteHandler: pasteHandler)
@@ -54,6 +56,7 @@ private struct UITextViewWrapper: UIViewRepresentable {
 
     @Binding var text: NSAttributedString
     @Binding var presendCallback: (() -> Void)?
+    @Binding var selectedRange: NSRange
 
     let maxHeight: CGFloat
 
@@ -105,7 +108,9 @@ private struct UITextViewWrapper: UIViewRepresentable {
         // Prevent the textView from inheriting attributes from mention pills
         textView.typingAttributes = [.font: font,
                                      .foregroundColor: UIColor.compound.textPrimary]
-
+        DispatchQueue.main.async {
+            selectedRange = textView.selectedRange
+        }
         if textView.attributedText != text {
             // Remember the selection if only the attributes have changed.
             let selection = textView.attributedText.string == text.string ? textView.selectedTextRange : nil
@@ -331,6 +336,7 @@ struct MessageComposerTextField_Previews: PreviewProvider, TestablePreview {
             MessageComposerTextField(placeholder: "Placeholder",
                                      text: $text,
                                      presendCallback: .constant(nil),
+                                     selectedRange: .constant(NSRange(location: 0, length: 0)),
                                      maxHeight: 300,
                                      keyHandler: { _ in },
                                      pasteHandler: { _ in })

UnitTests/Sources/CompletionSuggestionServiceTests.swift

@@ -101,6 +101,57 @@ final class CompletionSuggestionServiceTests: XCTestCase {
         service.setSuggestionTrigger(.init(type: .user, text: "", range: .init()))
         try await deferred.fulfill()
     }
+
+    func testUserSuggestionInDifferentMessagePositions() async throws {
+        let alice: RoomMemberProxyMock = .mockAlice
+        let members: [RoomMemberProxyMock] = [alice, .mockBob, .mockCharlie, .mockMe]
+        let roomProxyMock = JoinedRoomProxyMock(.init(name: "test", members: members))
+        let service = CompletionSuggestionService(roomProxy: roomProxyMock)
+
+        var deferred = deferFulfillment(service.suggestionsPublisher) { suggestion in
+            suggestion == [.user(item: .init(id: alice.userID, displayName: alice.displayName, avatarURL: alice.avatarURL, range: .init(location: 0, length: 3)))]
+        }
+        service.processTextMessage("@al hello", selectedRange: .init(location: 0, length: 1))
+        try await deferred.fulfill()
+
+        deferred = deferFulfillment(service.suggestionsPublisher) { suggestion in
+            suggestion == [.user(item: .init(id: alice.userID, displayName: alice.displayName, avatarURL: alice.avatarURL, range: .init(location: 5, length: 3)))]
+        }
+        service.processTextMessage("test @al", selectedRange: .init(location: 5, length: 1))
+        try await deferred.fulfill()
+
+        deferred = deferFulfillment(service.suggestionsPublisher) { suggestion in
+            suggestion == [.user(item: .init(id: alice.userID, displayName: alice.displayName, avatarURL: alice.avatarURL, range: .init(location: 5, length: 3)))]
+        }
+        service.processTextMessage("test @al test", selectedRange: .init(location: 5, length: 1))
+        try await deferred.fulfill()
+    }
+
+    func testUserSuggestionWithMultipleMentionSymbol() async throws {
+        let alice: RoomMemberProxyMock = .mockAlice
+        let bob: RoomMemberProxyMock = .mockBob
+        let members: [RoomMemberProxyMock] = [alice, bob, .mockCharlie, .mockMe]
+        let roomProxyMock = JoinedRoomProxyMock(.init(name: "test", members: members))
+        let service = CompletionSuggestionService(roomProxy: roomProxyMock)
+
+        var deffered = deferFulfillment(service.suggestionsPublisher) { suggestion in
+            suggestion == [.user(item: .init(id: alice.userID, displayName: alice.displayName, avatarURL: alice.avatarURL, range: .init(location: 0, length: 3)))]
+        }
+        service.processTextMessage("@al test @bo", selectedRange: .init(location: 0, length: 1))
+        try await deffered.fulfill()
+
+        deffered = deferFulfillment(service.suggestionsPublisher) { suggestion in
+            suggestion == [.user(item: .init(id: bob.userID, displayName: bob.displayName, avatarURL: bob.avatarURL, range: .init(location: 9, length: 3)))]
+        }
+        service.processTextMessage("@al test @bo", selectedRange: .init(location: 9, length: 1))
+        try await deffered.fulfill()
+
+        deffered = deferFulfillment(service.suggestionsPublisher) { suggestion in
+            suggestion == []
+        }
+        service.processTextMessage("@al test @bo", selectedRange: .init(location: 4, length: 1))
+        try await deffered.fulfill()
+    }
 }
 
 private extension MentionSuggestionItem {