Enhancement: AI chat UX tweaks (#14415)

src-ui/src/app/components/chat/chat/chat.component.html

@@ -1,51 +1,85 @@
 
-<li ngbDropdown class="nav-item" (openChange)="onOpenChange($event)">
+<li ngbDropdown class="nav-item" display="dynamic" placement="bottom-end" [popperOptions]="popperOptions" (openChange)="onOpenChange($event)">
   <button class="btn navbar-action border-0" id="chatDropdown" ngbDropdownToggle aria-label="Chat" i18n-aria-label>
     <i-bs width="1.3em" height="1.3em" name="chatSquareDots"></i-bs>
   </button>
-  <div ngbDropdownMenu class="dropdown-menu-end shadow p-3" aria-labelledby="chatDropdown">
-    <div class="chat-container bg-light p-2">
-      <div class="chat-messages small">
-        @for (message of messages(); track message) {
-          <div class="message d-flex flex-row small" [class.justify-content-end]="message.role === 'user'">
-            <div class="p-2 m-2" [class.bg-body]="message.role === 'user'">
-              @if (message.role === 'assistant') {
-                <div class="chat-markdown text-break text-wrap" [innerHTML]="message.content | markdown"></div>
-                @if (message.isStreaming) { <span class="blinking-cursor">|</span> }
-              } @else {
-                <span class="text-break">{{ message.content }}</span>
-              }
-              @if (message.role === 'assistant' && message.references?.length) {
-                <div class="chat-references list-group mt-3">
-                  @for (reference of message.references; track reference.id) {
-                    <a class="list-group-item list-group-item-action d-flex text-primary text-break" [routerLink]="['/documents', reference.id]">
-                      <i-bs width="0.9em" height="0.9em" name="file-text" class="me-1"></i-bs><span>{{ reference.title }}</span>
-                    </a>
-                  }
-                </div>
-              }
-            </div>
-          </div>
+  <div ngbDropdownMenu class="dropdown-menu-end shadow p-0 overflow-hidden" aria-labelledby="chatDropdown">
+    <div class="d-flex align-items-center border-bottom px-3 py-2">
+      <i-bs width="1em" height="1em" name="stars" class="text-primary me-2"></i-bs>
+      <span class="fw-semibold small">
+        @if (documentId()) {
+          <ng-container i18n>Ask about this document</ng-container>
+        } @else {
+          <ng-container i18n>Ask about your documents</ng-container>
         }
-        <div #scrollAnchor></div>
-      </div>
+      </span>
+      @if (messages().length) {
+        <button class="btn btn-sm btn-link text-muted ms-auto p-0" type="button" (click)="clearChat()" title="Clear chat" i18n-title>
+          <i-bs width="1em" height="1em" name="arrow-counterclockwise"></i-bs>
+        </button>
+      }
+    </div>
 
-      <form class="chat-input">
-        <label class="visually-hidden" for="chatInput" i18n>Message</label>
-        <div class="input-group">
-          <input
-            #chatInput
-            id="chatInput"
-            class="form-control form-control-sm" name="chatInput" type="text"
+    <div class="chat-messages small px-2">
+      @if (!messages().length) {
+        <p class="text-muted text-center py-4 px-3 mb-0" i18n>Answers come from your documents, with links to their sources.</p>
+      }
+      @for (message of messages(); track message) {
+        <div class="message d-flex flex-row" [class.justify-content-end]="message.role === 'user'" [class.mt-3]="message.role === 'user' && !$first">
+          <div class="p-2 m-2" [class.bg-body-secondary]="message.role === 'user'" [class.rounded-3]="message.role === 'user'" [class.flex-grow-1]="message.role === 'assistant'">
+            @if (message.isStreaming && !message.content) {
+              <div class="d-flex align-items-center text-muted">
+                <div class="spinner-border spinner-border-sm me-2" role="status"></div>
+                @if (slowResponse()) {
+                  <ng-container i18n>Still thinking...</ng-container>
+                } @else {
+                  <ng-container i18n>Thinking...</ng-container>
+                }
+              </div>
+            } @else if (message.role === 'assistant') {
+              <div class="chat-markdown text-break text-wrap" [class.streaming]="message.isStreaming" [innerHTML]="message.content | markdown"></div>
+            } @else {
+              <span class="text-break">{{ message.content }}</span>
+            }
+            @if (message.role === 'assistant' && !message.isStreaming && message.references?.length) {
+              <div class="chat-references list-group mt-3">
+                <div class="list-group-item text-muted small py-1" i18n>Sources</div>
+                @for (reference of message.references; track reference.id) {
+                  <a class="list-group-item list-group-item-action d-flex align-items-center text-primary" [routerLink]="['/documents', reference.id]" [title]="reference.title">
+                    <i-bs width="0.9em" height="0.9em" name="file-text" class="me-2 flex-shrink-0"></i-bs><span class="text-truncate">{{ reference.title }}</span>
+                  </a>
+                }
+              </div>
+            }
+          </div>
+        </div>
+      }
+      <div #scrollAnchor></div>
+    </div>
+
+    <form class="chat-input border-top p-2">
+      <label class="visually-hidden" for="chatInput" i18n>Message</label>
+      <div class="input-group">
+        <input
+          #chatInput
+          id="chatInput"
+          class="form-control" name="chatInput" type="text"
             [placeholder]="placeholder"
             [disabled]="loading()"
             [ngModel]="input()"
             (ngModelChange)="input.set($event)"
             (keydown)="searchInputKeyDown($event)"
-            />
-          <button class="btn btn-sm btn-secondary" type="button" (click)="sendMessage()" [disabled]="loading()">Send</button>
-        </div>
-      </form>
-    </div>
+          />
+        @if (loading()) {
+          <button class="btn btn-outline-secondary" type="button" (click)="stopStreaming()" title="Stop" i18n-title aria-label="Stop" i18n-aria-label>
+            <i-bs width="1em" height="1em" name="x-lg"></i-bs>
+          </button>
+        } @else {
+          <button class="btn btn-primary" type="button" (click)="sendMessage()" title="Send" i18n-title aria-label="Send" i18n-aria-label>
+            <i-bs width="1em" height="1em" name="arrow-return-left"></i-bs>
+          </button>
+        }
+      </div>
+    </form>
   </div>
 </li>

src-ui/src/app/components/chat/chat/chat.component.scss

@@ -1,9 +1,9 @@
 .dropdown-menu {
-  width: var(--pngx-toast-max-width);
+  width: min(36rem, calc(100vw - 20px));
 }
 
 .chat-messages {
-  max-height: 350px;
+  max-height: min(60dvh, 36rem);
   overflow-y: auto;
   white-space: pre-wrap;
 }
@@ -16,24 +16,29 @@
   white-space: initial;
 }
 
-@media screen and (max-width: 400px) {
-  :host ::ng-deep .dropdown-menu-end {
-    right: -3rem;
+@media screen and (max-width: 575.98px) {
+  .chat-messages {
+    max-height: calc(100dvh - 12rem);
   }
 }
 
-.blinking-cursor {
-  font-weight: bold;
-  font-size: 1.2em;
-  animation: blink 1s step-end infinite;
+.chat-markdown.streaming ::ng-deep {
+  > :last-child:not(ul, ol, table)::after,
+  > :is(ul, ol):last-child > li:last-child::after {
+    content: '';
+    display: inline-block;
+    width: 2px;
+    height: 1.05em;
+    margin-left: 2px;
+    background-color: currentColor;
+    vertical-align: -0.15em;
+    animation: blink 1s step-end infinite;
+  }
 }
 
 @keyframes blink {
-  from, to {
-    opacity: 0;
-  }
   50% {
-    opacity: 1;
+    opacity: 0;
   }
 }
 

src-ui/src/app/components/chat/chat/chat.component.spec.ts

@@ -80,8 +80,16 @@ describe('ChatComponent', () => {
     expect(component.messages()[0].content).toBe('Hello')
     expect(component.loading()).toBe(true)
 
+    fixture.detectChanges()
+    const messagesEl = fixture.nativeElement.querySelector('.chat-messages')
+    expect(messagesEl.querySelector('.spinner-border')).not.toBeNull()
+    expect(messagesEl.textContent).toContain('Thinking...')
+
     mockStream$.next('Hi')
     expect(component.messages()[1].content).toBe('H')
+    fixture.detectChanges()
+    expect(messagesEl.querySelector('.spinner-border')).toBeNull()
+    expect(messagesEl.querySelector('.chat-markdown.streaming')).not.toBeNull()
     mockStream$.next('Hi there')
     // advance time to process the typewriter effect
     await jest.runAllTimersAsync()
@@ -96,6 +104,8 @@ describe('ChatComponent', () => {
     await fixture.whenStable()
     expect(component.loading()).toBe(false)
     expect(component.messages()[1].isStreaming).toBe(false)
+    fixture.detectChanges()
+    expect(messagesEl.querySelector('.chat-markdown.streaming')).toBeNull()
     expect(fixture.nativeElement.querySelector('#chatInput').disabled).toBe(
       false
     )
@@ -123,6 +133,10 @@ describe('ChatComponent', () => {
     mockStream$.next(
       `Hi there${CHAT_METADATA_DELIMITER}{"references":[{"id":42,"title":"Bread Recipe"}]}`
     )
+    fixture.detectChanges()
+    expect(fixture.nativeElement.querySelector('.chat-references')).toBeNull()
+
+    mockStream$.complete()
     jest.advanceTimersByTime(1000)
     fixture.detectChanges()
 
@@ -156,13 +170,96 @@ describe('ChatComponent', () => {
     component.input.set('Hello')
     component.sendMessage()
 
+    mockStream$.next('Partial')
     mockStream$.error('Error')
-    expect(component.messages()[1].content).toContain(
-      '⚠️ Error receiving response.'
+    expect(component.messages()[1].content).toBe(
+      'Partial\n\n⚠️ Error receiving response.'
     )
     expect(component.loading()).toBe(false)
   })
 
+  it('should keep streaming until the typewriter catches up', () => {
+    component.input.set('Hello')
+    component.sendMessage()
+
+    mockStream$.next('Hi there')
+    mockStream$.complete()
+    expect(component.messages()[1].isStreaming).toBe(true)
+    expect(component.loading()).toBe(true)
+
+    jest.advanceTimersByTime(1000)
+    expect(component.messages()[1].content).toBe('Hi there')
+    expect(component.messages()[1].isStreaming).toBe(false)
+    expect(component.loading()).toBe(false)
+  })
+
+  it('should show a slow response message while waiting', () => {
+    component.input.set('Hello')
+    component.sendMessage()
+    fixture.detectChanges()
+    const messagesEl = fixture.nativeElement.querySelector('.chat-messages')
+    expect(messagesEl.textContent).not.toContain('Still thinking...')
+
+    jest.advanceTimersByTime(8000)
+    fixture.detectChanges()
+    expect(messagesEl.textContent).toContain('Still thinking...')
+
+    mockStream$.next('Hi')
+    expect(component.slowResponse()).toBe(false)
+  })
+
+  it('should stop streaming and keep the partial response', () => {
+    component.input.set('Hello')
+    component.sendMessage()
+    fixture.detectChanges()
+    const stopButton = fixture.nativeElement.querySelector('.chat-input button')
+    expect(stopButton.getAttribute('aria-label')).toBe('Stop')
+
+    mockStream$.next('Hi there')
+    jest.advanceTimersByTime(20)
+    stopButton.click()
+
+    expect(mockStream$.observed).toBe(false)
+    expect(component.messages()[1].content).toBe('Hi there')
+    expect(component.messages()[1].isStreaming).toBe(false)
+    expect(component.loading()).toBe(false)
+
+    jest.advanceTimersByTime(1000)
+    expect(component.messages()[1].content).toBe('Hi there')
+  })
+
+  it('should drop the empty response when stopped before any content', () => {
+    component.input.set('Hello')
+    component.sendMessage()
+    component.stopStreaming()
+
+    expect(component.messages()).toHaveLength(1)
+    expect(component.loading()).toBe(false)
+    component.stopStreaming() // no-op once stopped
+    expect(component.messages()).toHaveLength(1)
+  })
+
+  it('should clear the conversation', () => {
+    component.input.set('Hello')
+    component.sendMessage()
+    mockStream$.next('Hi there')
+    fixture.detectChanges()
+
+    fixture.nativeElement.querySelector('button[title="Clear chat"]').click()
+    expect(component.messages()).toHaveLength(0)
+    expect(component.loading()).toBe(false)
+    expect(mockStream$.observed).toBe(false)
+
+    fixture.detectChanges()
+    jest.advanceTimersByTime(10)
+    expect(document.activeElement).toBe(
+      fixture.nativeElement.querySelector('#chatInput')
+    )
+    expect(fixture.nativeElement.textContent).toContain(
+      'Answers come from your documents'
+    )
+  })
+
   it('should enqueue typewriter chunks correctly', () => {
     const message = { content: '', role: 'assistant', isStreaming: true }
     component.enqueueTypewriter(null, message as any) // coverage for null

src-ui/src/app/components/chat/chat/chat.component.ts

@@ -10,13 +10,16 @@ import { FormsModule, ReactiveFormsModule } from '@angular/forms'
 import { NavigationEnd, Router, RouterModule } from '@angular/router'
 import { NgbDropdownModule } from '@ng-bootstrap/ng-bootstrap'
 import { NgxBootstrapIconsModule } from 'ngx-bootstrap-icons'
+import { filter, map, Subscription } from 'rxjs'
 import { MarkdownPipe } from 'src/app/pipes/markdown.pipe'
-import { filter, map } from 'rxjs'
 import {
   ChatMessage,
   ChatService,
   parseChatResponse,
 } from 'src/app/services/chat.service'
+import { pngxPopperOptions } from 'src/app/utils/popper-options'
+
+const SLOW_RESPONSE_DELAY_MS = 8000
 
 @Component({
   selector: 'pngx-chat',
@@ -36,6 +39,8 @@ export class ChatComponent implements OnInit {
   readonly loading = signal(false)
   readonly input = signal('')
   readonly documentId = signal<number>(undefined)
+  readonly slowResponse = signal(false)
+  public popperOptions = pngxPopperOptions
 
   private chatService: ChatService = inject(ChatService)
   private router: Router = inject(Router)
@@ -45,6 +50,11 @@ export class ChatComponent implements OnInit {
 
   private typewriterBuffer: string[] = []
   private typewriterActive = false
+  private typewriterTimeout: ReturnType<typeof setTimeout>
+  private streamSubscription: Subscription
+  private streamingMessage: ChatMessage
+  private streamFinished = false
+  private slowResponseTimeout: ReturnType<typeof setTimeout>
 
   public get placeholder(): string {
     return this.documentId()
@@ -83,47 +93,96 @@ export class ChatComponent implements OnInit {
     }
     this.messages.update((messages) => [...messages, assistantMessage])
     this.loading.set(true)
+    this.streamingMessage = assistantMessage
+    this.streamFinished = false
+    this.slowResponseTimeout = setTimeout(
+      () => this.slowResponse.set(true),
+      SLOW_RESPONSE_DELAY_MS
+    )
 
     let lastVisibleContent = ''
 
-    this.chatService.streamChat(this.documentId(), this.input()).subscribe({
-      next: (chunk) => {
-        const nextResponse = parseChatResponse(chunk)
+    this.streamSubscription = this.chatService
+      .streamChat(this.documentId(), this.input())
+      .subscribe({
+        next: (chunk) => {
+          this.clearSlowResponse()
+          const nextResponse = parseChatResponse(chunk)
 
-        if (nextResponse.content.length < lastVisibleContent.length) {
-          this.resetTypewriter(assistantMessage, nextResponse.content)
-          lastVisibleContent = nextResponse.content
-        } else {
-          const visibleDelta = nextResponse.content.substring(
-            lastVisibleContent.length
-          )
-          lastVisibleContent = nextResponse.content
-          this.enqueueTypewriter(visibleDelta, assistantMessage)
-        }
+          if (nextResponse.content.length < lastVisibleContent.length) {
+            this.resetTypewriter(assistantMessage, nextResponse.content)
+            lastVisibleContent = nextResponse.content
+          } else {
+            const visibleDelta = nextResponse.content.substring(
+              lastVisibleContent.length
+            )
+            lastVisibleContent = nextResponse.content
+            this.enqueueTypewriter(visibleDelta, assistantMessage)
+          }
 
-        assistantMessage.references = nextResponse.references
-        this.notifyMessagesChanged()
-      },
-      error: () => {
-        assistantMessage.content += '\n\n⚠️ Error receiving response.'
-        assistantMessage.isStreaming = false
-        this.notifyMessagesChanged()
-        this.loading.set(false)
-      },
-      complete: () => {
-        assistantMessage.isStreaming = false
-        this.notifyMessagesChanged()
-        this.loading.set(false)
-        this.scrollToBottom()
-      },
-    })
+          assistantMessage.references = nextResponse.references
+          this.notifyMessagesChanged()
+        },
+        error: () => {
+          this.flushTypewriter(assistantMessage)
+          assistantMessage.content += '\n\n⚠️ Error receiving response.'
+          this.finishStreaming(assistantMessage)
+        },
+        complete: () => {
+          // let the typewriter catch up before hiding the cursor
+          this.streamFinished = true
+          if (!this.typewriterActive) this.finishStreaming(assistantMessage)
+        },
+      })
 
     this.input.set('')
   }
 
-  private resetTypewriter(message: ChatMessage, content: string): void {
+  stopStreaming(): void {
+    const message = this.streamingMessage
+    if (!message?.isStreaming) return
+
+    this.streamSubscription?.unsubscribe()
+    this.flushTypewriter(message)
+    if (!message.content) {
+      this.messages.update((messages) => messages.filter((m) => m !== message))
+    }
+    this.finishStreaming(message)
+  }
+
+  clearChat(): void {
+    this.stopStreaming()
+    this.messages.set([])
+    setTimeout(() => this.chatInput?.nativeElement.focus())
+  }
+
+  private finishStreaming(message: ChatMessage): void {
+    this.clearSlowResponse()
+    this.streamFinished = false
+    message.isStreaming = false
+    this.notifyMessagesChanged()
+    this.loading.set(false)
+    this.scrollToBottom()
+  }
+
+  private clearSlowResponse(): void {
+    clearTimeout(this.slowResponseTimeout)
+    this.slowResponse.set(false)
+  }
+
+  private flushTypewriter(message: ChatMessage): void {
+    message.content += this.typewriterBuffer.join('')
+    this.cancelTypewriter()
+  }
+
+  private cancelTypewriter(): void {
+    clearTimeout(this.typewriterTimeout)
     this.typewriterBuffer = []
     this.typewriterActive = false
+  }
+
+  private resetTypewriter(message: ChatMessage, content: string): void {
+    this.cancelTypewriter()
     message.content = content
     this.notifyMessagesChanged()
     this.scrollToBottom()
@@ -143,6 +202,7 @@ export class ChatComponent implements OnInit {
   playTypewriter(message: ChatMessage): void {
     if (this.typewriterBuffer.length === 0) {
       this.typewriterActive = false
+      if (this.streamFinished) this.finishStreaming(message)
       return
     }
 
@@ -151,7 +211,8 @@ export class ChatComponent implements OnInit {
     this.notifyMessagesChanged()
     this.scrollToBottom()
 
-    setTimeout(() => this.playTypewriter(message), 10) // 10ms per character
+    // 10ms per character
+    this.typewriterTimeout = setTimeout(() => this.playTypewriter(message), 10)
   }
 
   private notifyMessagesChanged(): void {

src-ui/src/main.ts

@@ -32,6 +32,7 @@ import {
   arrowDownUp,
   arrowLeft,
   arrowRepeat,
+  arrowReturnLeft,
   arrowRight,
   arrowRightShort,
   arrowUpRight,
@@ -284,6 +285,7 @@ const icons = {
   arrowDownUp,
   arrowLeft,
   arrowRepeat,
+  arrowReturnLeft,
   arrowRight,
   arrowRightShort,
   arrowUpRight,