feat(codewhisperer): auto trigger improvements (#3093)

## Problem
Current auto-trigger heuristics is not very responsive

## Solution
Replacing the character number based triggering rule with an idle time based triggering rule to make the triggering more aggressive

Author: zixlin7

.changes/next-release/Feature-778c35c9-3c44-40e0-a6b1-4e656c74eadf.json

@@ -0,0 +1,4 @@
+{
+	"type": "Feature",
+	"description": "CodeWhisperer: more responsive Auto-Suggestions"
+}

src/codewhisperer/commands/invokeRecommendation.ts

@@ -10,7 +10,6 @@ import { DefaultCodeWhispererClient } from '../client/codewhisperer'
 import { InlineCompletion } from '../service/inlineCompletion'
 import { isCloud9 } from '../../shared/extensionUtilities'
 import { RecommendationHandler } from '../service/recommendationHandler'
-import { KeyStrokeHandler } from '../service/keyStrokeHandler'
 import { isInlineCompletionEnabled } from '../util/commonUtil'
 import { InlineCompletionService } from '../service/inlineCompletionService'
 import { AuthUtil } from '../util/authUtil'
@@ -52,7 +51,6 @@ export async function invokeRecommendation(
                 RecommendationHandler.instance.isValidResponse()
             )
         }
-        KeyStrokeHandler.instance.keyStrokeCount = 0
         if (isCloud9()) {
             if (RecommendationHandler.instance.isGenerateRecommendationInProgress) {
                 return

src/codewhisperer/models/constants.ts

@@ -20,6 +20,8 @@ export const promiseTimeoutLimit = 15 // seconds
 
 export const invocationKeyThreshold = 15
 
+export const idleTimerPollPeriod = 25 // milliseconds
+
 export const specialCharactersList = ['{', '[', '(', ':', '\t', '\n']
 
 export const normalTextChangeRegex = /[A-Za-z0-9]/g

src/codewhisperer/service/inlineCompletionService.ts

@@ -419,6 +419,10 @@ export class InlineCompletionService {
         this.statusBar.show()
     }
 
+    isPaginationRunning(): boolean {
+        return this._isPaginationRunning
+    }
+
     hideCodeWhispererStatusBar() {
         this.statusBar.hide()
     }

src/codewhisperer/service/keyStrokeHandler.ts

@@ -30,11 +30,11 @@ export class KeyStrokeHandler {
     /**
      * Key stroke count for automated trigger
      */
-    public keyStrokeCount: number
+
+    private idleTriggerTimer?: NodeJS.Timer
 
     constructor() {
         this.specialChar = ''
-        this.keyStrokeCount = 0
     }
 
     static #instance: KeyStrokeHandler
@@ -43,6 +43,49 @@ export class KeyStrokeHandler {
         return (this.#instance ??= new this())
     }
 
+    public startIdleTimeTriggerTimer(
+        event: vscode.TextDocumentChangeEvent,
+        editor: vscode.TextEditor,
+        client: DefaultCodeWhispererClient,
+        config: ConfigurationEntry
+    ) {
+        if (this.idleTriggerTimer) {
+            clearInterval(this.idleTriggerTimer)
+            this.idleTriggerTimer = undefined
+        }
+        if (!this.shouldTriggerIdleTime()) {
+            return
+        }
+        this.idleTriggerTimer = setInterval(() => {
+            const duration = (performance.now() - RecommendationHandler.instance.lastInvocationTime) / 1000
+            if (duration < CodeWhispererConstants.invocationTimeIntervalThreshold) {
+                return
+            }
+
+            try {
+                this.invokeAutomatedTrigger('IdleTime', editor, client, config)
+            } finally {
+                if (this.idleTriggerTimer) {
+                    clearInterval(this.idleTriggerTimer)
+                    this.idleTriggerTimer = undefined
+                }
+            }
+        }, CodeWhispererConstants.idleTimerPollPeriod)
+    }
+
+    public shouldTriggerIdleTime(): boolean {
+        if (isCloud9() && RecommendationHandler.instance.isGenerateRecommendationInProgress) {
+            return false
+        }
+        if (isInlineCompletionEnabled() && InlineCompletionService.instance.isPaginationRunning()) {
+            return false
+        }
+        if (InlineCompletion.instance.getIsActive || InlineCompletion.instance.isPaginationRunning()) {
+            return false
+        }
+        return true
+    }
+
     async processKeyStroke(
         event: vscode.TextDocumentChangeEvent,
         editor: vscode.TextEditor,
@@ -77,35 +120,23 @@ export class KeyStrokeHandler {
 
             let triggerType: CodewhispererAutomatedTriggerType | undefined
             const changedSource = new DefaultDocumentChangedType(event.contentChanges).checkChangeSource()
-            // Time duration between 2 invocations should be greater than the threshold
-            // This threshold does not applies to Enter | SpecialCharacters | IntelliSenseAcceptance type auto trigger.
-            const duration = Math.floor((performance.now() - RecommendationHandler.instance.lastInvocationTime) / 1000)
+            if ([DocumentChangedSource.RegularKey].includes(changedSource)) {
+                this.startIdleTimeTriggerTimer(event, editor, client, config)
+            }
             switch (changedSource) {
                 case DocumentChangedSource.EnterKey: {
-                    this.keyStrokeCount += 1
                     triggerType = 'Enter'
                     break
                 }
                 case DocumentChangedSource.SpecialCharsKey: {
-                    this.keyStrokeCount += 1
                     triggerType = 'SpecialCharacters'
                     break
                 }
                 case DocumentChangedSource.IntelliSense: {
-                    this.keyStrokeCount += 1
                     triggerType = 'IntelliSenseAcceptance'
                     break
                 }
                 case DocumentChangedSource.RegularKey: {
-                    // text length can be greater than 1 in Cloud9
-                    this.keyStrokeCount += event.contentChanges[0].text.length
-                    if (
-                        this.keyStrokeCount >= 15 &&
-                        duration >= CodeWhispererConstants.invocationTimeIntervalThreshold
-                    ) {
-                        triggerType = 'KeyStrokeCount'
-                        this.keyStrokeCount = 0
-                    }
                     break
                 }
                 default: {
@@ -129,7 +160,6 @@ export class KeyStrokeHandler {
         config: ConfigurationEntry
     ): Promise<void> {
         if (editor) {
-            this.keyStrokeCount = 0
             if (isCloud9()) {
                 if (RecommendationHandler.instance.isGenerateRecommendationInProgress) {
                     return

src/test/codewhisperer/commands/invokeRecommendation.test.ts

@@ -11,7 +11,6 @@ import { ConfigurationEntry } from '../../../codewhisperer/models/model'
 import { invokeRecommendation } from '../../../codewhisperer/commands/invokeRecommendation'
 import { InlineCompletion } from '../../../codewhisperer/service/inlineCompletion'
 import { InlineCompletionService } from '../../../codewhisperer/service/inlineCompletionService'
-import { KeyStrokeHandler } from '../../../codewhisperer/service/keyStrokeHandler'
 
 describe('invokeRecommendation', function () {
     describe('invokeRecommendation', function () {
@@ -40,18 +39,5 @@ describe('invokeRecommendation', function () {
             await invokeRecommendation(mockEditor, mockClient, config)
             assert.ok(getRecommendationStub.called || oldGetRecommendationStub.called)
         })
-
-        it('When called, keyStrokeCount should be set to 0', async function () {
-            const mockEditor = createMockTextEditor()
-            KeyStrokeHandler.instance.keyStrokeCount = 10
-            const config: ConfigurationEntry = {
-                isShowMethodsEnabled: true,
-                isManualTriggerEnabled: true,
-                isAutomatedTriggerEnabled: true,
-                isIncludeSuggestionsWithCodeReferencesEnabled: true,
-            }
-            await invokeRecommendation(mockEditor, mockClient, config)
-            assert.strictEqual(KeyStrokeHandler.instance.keyStrokeCount, 0)
-        })
     })
 })

src/test/codewhisperer/service/keyStrokeHandler.test.ts

@@ -33,9 +33,11 @@ describe('keyStrokeHandler', function () {
     })
     describe('processKeyStroke', async function () {
         let invokeSpy: sinon.SinonStub
+        let startTimerSpy: sinon.SinonStub
         let mockClient: codewhispererSdkClient.DefaultCodeWhispererClient
         beforeEach(function () {
             invokeSpy = sinon.stub(KeyStrokeHandler.instance, 'invokeAutomatedTrigger')
+            startTimerSpy = sinon.stub(KeyStrokeHandler.instance, 'startIdleTimeTriggerTimer')
             sinon.spy(RecommendationHandler.instance, 'getRecommendations')
             mockClient = new codewhispererSdkClient.DefaultCodeWhispererClient()
             resetCodeWhispererGlobalVariables()
@@ -62,6 +64,7 @@ describe('keyStrokeHandler', function () {
             const keyStrokeHandler = new KeyStrokeHandler()
             await keyStrokeHandler.processKeyStroke(mockEvent, mockEditor, mockClient, cfg)
             assert.ok(!invokeSpy.called)
+            assert.ok(!startTimerSpy.called)
         })
 
         it('Should not call invokeAutomatedTrigger when changed text matches active recommendation prefix', async function () {
@@ -87,6 +90,7 @@ describe('keyStrokeHandler', function () {
             )
             await KeyStrokeHandler.instance.processKeyStroke(mockEvent, mockEditor, mockClient, config)
             assert.ok(!invokeSpy.called)
+            assert.ok(!startTimerSpy.called)
         })
 
         it('Should not call invokeAutomatedTrigger when doing delete or undo (empty changed text)', async function () {
@@ -98,23 +102,10 @@ describe('keyStrokeHandler', function () {
             )
             await KeyStrokeHandler.instance.processKeyStroke(mockEvent, mockEditor, mockClient, config)
             assert.ok(!invokeSpy.called)
-        })
-
-        it('Should not call invokeAutomatedTrigger if previous text input is within 2 seconds and it is not a specialcharacter trigger \n', async function () {
-            KeyStrokeHandler.instance.keyStrokeCount = 14
-            const mockEditor = createMockTextEditor()
-            const mockEvent: vscode.TextDocumentChangeEvent = createTextDocumentChangeEvent(
-                mockEditor.document,
-                new vscode.Range(new vscode.Position(0, 0), new vscode.Position(0, 1)),
-                'a'
-            )
-            RecommendationHandler.instance.lastInvocationTime = performance.now() - 1500
-            await KeyStrokeHandler.instance.processKeyStroke(mockEvent, mockEditor, mockClient, config)
-            assert.ok(!invokeSpy.called)
+            assert.ok(!startTimerSpy.called)
         })
 
         it('Should call invokeAutomatedTrigger if previous text input is within 2 seconds but the new input is new line', async function () {
-            KeyStrokeHandler.instance.keyStrokeCount = 14
             const mockEditor = createMockTextEditor()
             const mockEvent: vscode.TextDocumentChangeEvent = createTextDocumentChangeEvent(
                 mockEditor.document,
@@ -127,7 +118,6 @@ describe('keyStrokeHandler', function () {
         })
 
         it('Should call invokeAutomatedTrigger if previous text input is within 2 seconds but the new input is a specialcharacter', async function () {
-            KeyStrokeHandler.instance.keyStrokeCount = 14
             const mockEditor = createMockTextEditor()
             const mockEvent: vscode.TextDocumentChangeEvent = createTextDocumentChangeEvent(
                 mockEditor.document,
@@ -200,31 +190,26 @@ describe('keyStrokeHandler', function () {
             assert.ok(!invokeSpy.called)
         })
 
-        it('Should call invokeAutomatedTrigger with arg KeyStrokeCount when invocationContext.keyStrokeCount reaches threshold', async function () {
+        it('Should not start idle trigger timer when inputing special characters', async function () {
             const mockEditor = createMockTextEditor()
             const mockEvent: vscode.TextDocumentChangeEvent = createTextDocumentChangeEvent(
                 mockEditor.document,
                 new vscode.Range(new vscode.Position(0, 0), new vscode.Position(0, 1)),
-                'a'
+                '('
             )
-            KeyStrokeHandler.instance.keyStrokeCount = 15
             await KeyStrokeHandler.instance.processKeyStroke(mockEvent, mockEditor, mockClient, config)
-            invokeSpy('KeyStrokeCount', mockEditor, mockClient)
-            assert.ok(invokeSpy.called)
+            assert.ok(!startTimerSpy.called)
         })
 
-        it('Should not call invokeAutomatedTrigger when user input is not special character and keyStrokeCount does not reach threshold, should increase invocationContext.keyStrokeCount by 1', async function () {
+        it('Should start idle trigger timer when inputing non-special characters', async function () {
             const mockEditor = createMockTextEditor()
             const mockEvent: vscode.TextDocumentChangeEvent = createTextDocumentChangeEvent(
                 mockEditor.document,
                 new vscode.Range(new vscode.Position(0, 0), new vscode.Position(0, 1)),
                 'a'
             )
-            RecommendationHandler.instance.lastInvocationTime = 0
-            KeyStrokeHandler.instance.keyStrokeCount = 8
             await KeyStrokeHandler.instance.processKeyStroke(mockEvent, mockEditor, mockClient, config)
-            assert.ok(!invokeSpy.called)
-            assert.strictEqual(KeyStrokeHandler.instance.keyStrokeCount, 9)
+            assert.ok(startTimerSpy.called)
         })
     })
 
@@ -250,15 +235,15 @@ describe('keyStrokeHandler', function () {
             await keyStrokeHandler.invokeAutomatedTrigger('Enter', mockEditor, mockClient, config)
             assert.ok(getRecommendationsStub.calledOnce || oldGetRecommendationsStub.calledOnce)
         })
+    })
 
-        it('should reset invocationContext.keyStrokeCount to 0', async function () {
-            const mockEditor = createMockTextEditor()
-            KeyStrokeHandler.instance.keyStrokeCount = 10
-            sinon
-                .stub(RecommendationHandler.instance, 'getServerResponse')
-                .resolves([{ content: 'import math' }, { content: 'def two_sum(nums, target):' }])
-            await KeyStrokeHandler.instance.invokeAutomatedTrigger('Enter', mockEditor, mockClient, config)
-            assert.strictEqual(KeyStrokeHandler.instance.keyStrokeCount, 0)
+    describe('shouldTriggerIdleTime', function () {
+        it('should return false when inline is enabled and inline completion is in progress ', function () {
+            const keyStrokeHandler = new KeyStrokeHandler()
+            sinon.stub(InlineCompletionService.instance, 'isPaginationRunning').returns(true)
+            sinon.stub(InlineCompletion.instance, 'isPaginationRunning').returns(true)
+            const result = keyStrokeHandler.shouldTriggerIdleTime()
+            assert.strictEqual(result, false)
         })
     })