Toggle suggestions (#13)

* Enables users to toggle between suggestions

* Disables suggestion toggling when user has typed ahead

* Removes println for incrementing and decrementing

* Fixes formatting

* Makes adjustment for various checkstyle items

plugin/plugin.xml

@@ -97,6 +97,16 @@
             name="Reject Suggestions"
             id="software.aws.toolkits.eclipse.amazonq.commands.rejectSuggestions">
         </command>
+        <command
+              categoryId="software.aws.toolkits.eclipse.amazonq.commands.category"
+              id="software.aws.toolkits.eclipse.amazonq.commands.toggleSuggestionsForward"
+              name="Toggle Suggestions Forward">
+        </command>
+        <command
+              categoryId="software.aws.toolkits.eclipse.amazonq.commands.category"
+              id="software.aws.toolkits.eclipse.amazonq.commands.toggleSuggestionsBackward"
+              name="Toggle Suggestions Backward">
+        </command>
     </extension>
 
     <extension point="org.eclipse.ui.handlers">
@@ -112,6 +122,14 @@
                 class="software.aws.toolkits.eclipse.amazonq.handlers.QRejectSuggestionsHandler"
                 commandId="software.aws.toolkits.eclipse.amazonq.commands.rejectSuggestions">
         </handler>
+        <handler
+              class="software.aws.toolkits.eclipse.amazonq.handlers.QToggleSuggestionsForwardHandler"
+              commandId="software.aws.toolkits.eclipse.amazonq.commands.toggleSuggestionsForward">
+        </handler>
+        <handler
+              class="software.aws.toolkits.eclipse.amazonq.handlers.QToggleSuggestionsBackwardHandler"
+              commandId="software.aws.toolkits.eclipse.amazonq.commands.toggleSuggestionsBackward">
+        </handler>
     </extension>
 
     <extension point="org.eclipse.ui.bindings">
@@ -133,6 +151,18 @@
             schemeId="org.eclipse.ui.defaultAcceleratorConfiguration"
             sequence="ESC">
         </key>
+        <key
+              commandId="software.aws.toolkits.eclipse.amazonq.commands.toggleSuggestionsBackward"
+              contextId="org.eclipse.ui.textEditorScope"
+              schemeId="org.eclipse.ui.defaultAcceleratorConfiguration"
+              sequence="M3+[">
+        </key>
+        <key
+              commandId="software.aws.toolkits.eclipse.amazonq.commands.toggleSuggestionsForward"
+              contextId="org.eclipse.ui.textEditorScope"
+              schemeId="org.eclipse.ui.defaultAcceleratorConfiguration"
+              sequence="M3+]">
+        </key>
     </extension>
 
     <extension point="org.eclipse.ui.startup">

plugin/src/software/aws/toolkits/eclipse/amazonq/handlers/AbstractQToggleSuggestionsHandler.java

@@ -0,0 +1,61 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+package software.aws.toolkits.eclipse.amazonq.handlers;
+
+import org.eclipse.core.commands.AbstractHandler;
+import org.eclipse.core.commands.ExecutionEvent;
+
+import software.aws.toolkits.eclipse.amazonq.util.QInvocationSession;
+
+public abstract class AbstractQToggleSuggestionsHandler extends AbstractHandler {
+    public enum Direction {
+        FORWARD, BACKWARD
+    }
+
+    private Direction direction = Direction.FORWARD;
+
+    @Override
+    public final boolean isEnabled() {
+        QInvocationSession qInvocationSessionInstance = QInvocationSession.getInstance();
+        return qInvocationSessionInstance != null && !qInvocationSessionInstance.hasBeenTypedahead()
+                && qInvocationSessionInstance.isPreviewingSuggestions();
+    }
+
+    /**
+     * Executes the command when the user triggers the handler.
+     * <p>
+     * Subclasses overriding this method should ensure that the following conditions are met:
+     * </p>
+     * <ul>
+     *     <li>The method should make sure to set a direction of toggle</li>
+     *     <li>The method should make sure to call the super's counter part of this method</li>
+     * </ul>
+     *
+     * @param event The execution event that triggered the handler.
+     * @return The result of the execution, or <code>null</code> if there is no result.
+     *
+     * @implSpec
+     * Implementations should call {@code super.execute(event)} at the end to delegate the actual movement.
+     */
+    @Override
+    public Object execute(final ExecutionEvent event) {
+        QInvocationSession qInvocationSessionInstance = QInvocationSession.getInstance();
+
+        switch (direction) {
+        case FORWARD:
+            qInvocationSessionInstance.incrementCurentSuggestionIndex();
+            break;
+        case BACKWARD:
+            qInvocationSessionInstance.decrementCurrentSuggestionIndex();
+            break;
+        default:
+            qInvocationSessionInstance.incrementCurentSuggestionIndex();
+        }
+
+        return null;
+    }
+
+    protected final void setCommandDirection(final Direction direction) {
+        this.direction = direction;
+    }
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/handlers/QToggleSuggestionsBackwardHandler.java

@@ -0,0 +1,15 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+package software.aws.toolkits.eclipse.amazonq.handlers;
+
+import org.eclipse.core.commands.ExecutionEvent;
+
+public class QToggleSuggestionsBackwardHandler extends AbstractQToggleSuggestionsHandler {
+    // Actual command handler logic consolidated in parent class
+    @Override
+    public final Object execute(final ExecutionEvent event) {
+        super.setCommandDirection(Direction.BACKWARD);
+
+        return super.execute(event);
+    }
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/handlers/QToggleSuggestionsForwardHandler.java

@@ -0,0 +1,15 @@
+// Copyright 2024 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+package software.aws.toolkits.eclipse.amazonq.handlers;
+
+import org.eclipse.core.commands.ExecutionEvent;
+
+public class QToggleSuggestionsForwardHandler extends AbstractQToggleSuggestionsHandler {
+    // Actual command handler logic consolidated in parent class
+    @Override
+    public final Object execute(final ExecutionEvent event) {
+        super.setCommandDirection(Direction.FORWARD);
+
+        return super.execute(event);
+    }
+}

plugin/src/software/aws/toolkits/eclipse/amazonq/util/QInlineVerifyKeyListener.java

@@ -46,6 +46,8 @@ public void verifyKey(final VerifyEvent event) {
             // Here we conduct typeahead logic
             String currentSuggestion = qInvocationSessionInstance.getCurrentSuggestion().trim();
             int currentOffset = widget.getCaretOffset();
+            qInvocationSessionInstance
+                    .setHasBeenTypedahead(currentOffset - qInvocationSessionInstance.getInvocationOffset() > 0);
             IEclipsePreferences preferences = InstanceScope.INSTANCE.getNode("org.eclipse.jdt.ui");
             // This needs to be defaulted to true. This key is only present in the
             // preference store if it is set to false.
@@ -162,7 +164,6 @@ public void verifyKey(final VerifyEvent event) {
                         break;
                     }
                 }
-
                 leadingWhitespaceSkipped += newWs;
                 qInvocationSessionInstance.setLeadingWhitespaceSkipped(leadingWhitespaceSkipped);
             }

plugin/src/software/aws/toolkits/eclipse/amazonq/util/QInvocationSession.java

@@ -46,6 +46,7 @@ public final class QInvocationSession extends QResource {
     private Stack<Character> closingBrackets = new Stack<>();
     private boolean isLastKeyNewLine = false;
     private int[] headOffsetAtLine = new int[500];
+    private boolean hasBeenTypedahead = false;
 
     // Private constructor to prevent instantiation
     private QInvocationSession() {
@@ -307,6 +308,28 @@ public String getCurrentSuggestion() {
         return details.get(index).getSuggestion();
     }
 
+    public void decrementCurrentSuggestionIndex() {
+        if (suggestionsContext != null) {
+            suggestionsContext.decrementIndex();
+            getViewer().getTextWidget().redraw();
+        }
+    }
+
+    public void incrementCurentSuggestionIndex() {
+        if (suggestionsContext != null) {
+            suggestionsContext.incrementIndex();
+            getViewer().getTextWidget().redraw();
+        }
+    }
+
+    public void setHasBeenTypedahead(final boolean hasBeenTypedahead) {
+        this.hasBeenTypedahead = hasBeenTypedahead;
+    }
+
+    public boolean hasBeenTypedahead() {
+        return hasBeenTypedahead;
+    }
+
     // Additional methods for the session can be added here
     @Override
     public void dispose() {
@@ -319,6 +342,7 @@ public void dispose() {
         leadingWhitespaceSkipped = 0;
         isLastKeyNewLine = false;
         caretMovementReason = CaretMovementReason.UNEXAMINED;
+        hasBeenTypedahead = false;
         QInvocationSession.getInstance().getViewer().getTextWidget().redraw();
         widget.removePaintListener(paintListener);
         widget.removeCaretListener(caretListener);

plugin/src/software/aws/toolkits/eclipse/amazonq/util/QSuggestionsContext.java

@@ -25,5 +25,16 @@ public final void setCurrentIndex(final int index) {
         this.currentIndex = index;
     }
 
+    public final void incrementIndex() {
+        currentIndex = (currentIndex + 1) % details.size();
+    }
+
+    public final void decrementIndex() {
+        if (currentIndex - 1 < 0) {
+            currentIndex = details.size() - 1;
+        } else {
+            currentIndex--;
+        }
+    }
 }