Feature: Paperless AI (#10319)

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

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+
+<li ngbDropdown class="nav-item me-n2" (openChange)="onOpenChange($event)">
+  <button class="btn border-0" id="chatDropdown" ngbDropdownToggle>
+    <i-bs width="1.3em" height="1.3em" name="chatSquareDots"></i-bs>
+  </button>
+  <div ngbDropdownMenu class="dropdown-menu-end shadow p-3" aria-labelledby="chatDropdown">
+    <div class="chat-container bg-light p-2">
+      <div class="chat-messages font-monospace small">
+        @for (message of messages; track message) {
+          <div class="message d-flex flex-row small" [class.justify-content-end]="message.role === 'user'">
+            <span class="p-2 m-2" [class.bg-dark]="message.role === 'user'">
+              {{ message.content }}
+              @if (message.isStreaming) { <span class="blinking-cursor">|</span> }
+            </span>
+          </div>
+        }
+        <div #scrollAnchor></div>
+      </div>
+
+      <form class="chat-input">
+        <div class="input-group">
+          <input
+            #chatInput
+            class="form-control form-control-sm" name="chatInput" type="text"
+            [placeholder]="placeholder"
+            [disabled]="loading"
+            [(ngModel)]="input"
+            (keydown)="searchInputKeyDown($event)"
+            />
+          <button class="btn btn-sm btn-secondary" type="button" (click)="sendMessage()" [disabled]="loading">Send</button>
+        </div>
+      </form>
+    </div>
+  </div>
+</li>

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

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+.dropdown-menu {
+  width: var(--pngx-toast-max-width);
+}
+
+.chat-messages {
+  max-height: 350px;
+  overflow-y: auto;
+}
+
+.dropdown-toggle::after {
+  display: none;
+}
+
+.dropdown-item {
+  white-space: initial;
+}
+
+@media screen and (max-width: 400px) {
+  :host ::ng-deep .dropdown-menu-end {
+    right: -3rem;
+  }
+}
+
+.blinking-cursor {
+  font-weight: bold;
+  font-size: 1.2em;
+  animation: blink 1s step-end infinite;
+}
+
+@keyframes blink {
+  from, to {
+    opacity: 0;
+  }
+  50% {
+    opacity: 1;
+  }
+}

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

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+import { provideHttpClient, withInterceptorsFromDi } from '@angular/common/http'
+import { provideHttpClientTesting } from '@angular/common/http/testing'
+import { ElementRef } from '@angular/core'
+import { ComponentFixture, TestBed } from '@angular/core/testing'
+import { NavigationEnd, Router } from '@angular/router'
+import { allIcons, NgxBootstrapIconsModule } from 'ngx-bootstrap-icons'
+import { Subject } from 'rxjs'
+import { ChatService } from 'src/app/services/chat.service'
+import { ChatComponent } from './chat.component'
+
+describe('ChatComponent', () => {
+  let component: ChatComponent
+  let fixture: ComponentFixture<ChatComponent>
+  let chatService: ChatService
+  let router: Router
+  let routerEvents$: Subject<NavigationEnd>
+  let mockStream$: Subject<string>
+
+  beforeEach(async () => {
+    TestBed.configureTestingModule({
+      imports: [NgxBootstrapIconsModule.pick(allIcons), ChatComponent],
+      providers: [
+        provideHttpClient(withInterceptorsFromDi()),
+        provideHttpClientTesting(),
+      ],
+    }).compileComponents()
+
+    fixture = TestBed.createComponent(ChatComponent)
+    router = TestBed.inject(Router)
+    routerEvents$ = new Subject<any>()
+    jest
+      .spyOn(router, 'events', 'get')
+      .mockReturnValue(routerEvents$.asObservable())
+    chatService = TestBed.inject(ChatService)
+    mockStream$ = new Subject<string>()
+    jest
+      .spyOn(chatService, 'streamChat')
+      .mockReturnValue(mockStream$.asObservable())
+    component = fixture.componentInstance
+
+    jest.useFakeTimers()
+
+    fixture.detectChanges()
+
+    component.scrollAnchor.nativeElement.scrollIntoView = jest.fn()
+  })
+
+  it('should update documentId on initialization', () => {
+    jest.spyOn(router, 'url', 'get').mockReturnValue('/documents/123')
+    component.ngOnInit()
+    expect(component.documentId).toBe(123)
+  })
+
+  it('should update documentId on navigation', () => {
+    component.ngOnInit()
+    routerEvents$.next(new NavigationEnd(1, '/documents/456', '/documents/456'))
+    expect(component.documentId).toBe(456)
+  })
+
+  it('should return correct placeholder based on documentId', () => {
+    component.documentId = 123
+    expect(component.placeholder).toBe('Ask a question about this document...')
+    component.documentId = undefined
+    expect(component.placeholder).toBe('Ask a question about a document...')
+  })
+
+  it('should send a message and handle streaming response', () => {
+    component.input = 'Hello'
+    component.sendMessage()
+
+    expect(component.messages.length).toBe(2)
+    expect(component.messages[0].content).toBe('Hello')
+    expect(component.loading).toBe(true)
+
+    mockStream$.next('Hi')
+    expect(component.messages[1].content).toBe('H')
+    mockStream$.next('Hi there')
+    // advance time to process the typewriter effect
+    jest.advanceTimersByTime(1000)
+    expect(component.messages[1].content).toBe('Hi there')
+
+    mockStream$.complete()
+    expect(component.loading).toBe(false)
+    expect(component.messages[1].isStreaming).toBe(false)
+  })
+
+  it('should handle errors during streaming', () => {
+    component.input = 'Hello'
+    component.sendMessage()
+
+    mockStream$.error('Error')
+    expect(component.messages[1].content).toContain(
+      '⚠️ Error receiving response.'
+    )
+    expect(component.loading).toBe(false)
+  })
+
+  it('should enqueue typewriter chunks correctly', () => {
+    const message = { content: '', role: 'assistant', isStreaming: true }
+    component.enqueueTypewriter(null, message as any) // coverage for null
+    component.enqueueTypewriter('Hello', message as any)
+    expect(component['typewriterBuffer'].length).toBe(4)
+  })
+
+  it('should scroll to bottom after sending a message', () => {
+    const scrollSpy = jest.spyOn(
+      ChatComponent.prototype as any,
+      'scrollToBottom'
+    )
+    component.input = 'Test'
+    component.sendMessage()
+    expect(scrollSpy).toHaveBeenCalled()
+  })
+
+  it('should focus chat input when dropdown is opened', () => {
+    const focus = jest.fn()
+    component.chatInput = {
+      nativeElement: { focus: focus },
+    } as unknown as ElementRef<HTMLInputElement>
+
+    component.onOpenChange(true)
+    jest.advanceTimersByTime(15)
+    expect(focus).toHaveBeenCalled()
+  })
+
+  it('should send message on Enter key press', () => {
+    jest.spyOn(component, 'sendMessage')
+    const event = new KeyboardEvent('keydown', { key: 'Enter' })
+    component.searchInputKeyDown(event)
+    expect(component.sendMessage).toHaveBeenCalled()
+  })
+})

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

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+import { Component, ElementRef, inject, OnInit, ViewChild } from '@angular/core'
+import { FormsModule, ReactiveFormsModule } from '@angular/forms'
+import { NavigationEnd, Router } from '@angular/router'
+import { NgbDropdownModule } from '@ng-bootstrap/ng-bootstrap'
+import { NgxBootstrapIconsModule } from 'ngx-bootstrap-icons'
+import { filter, map } from 'rxjs'
+import { ChatMessage, ChatService } from 'src/app/services/chat.service'
+
+@Component({
+  selector: 'pngx-chat',
+  imports: [
+    FormsModule,
+    ReactiveFormsModule,
+    NgxBootstrapIconsModule,
+    NgbDropdownModule,
+  ],
+  templateUrl: './chat.component.html',
+  styleUrl: './chat.component.scss',
+})
+export class ChatComponent implements OnInit {
+  public messages: ChatMessage[] = []
+  public loading = false
+  public input: string = ''
+  public documentId!: number
+
+  private chatService: ChatService = inject(ChatService)
+  private router: Router = inject(Router)
+
+  @ViewChild('scrollAnchor') scrollAnchor!: ElementRef<HTMLDivElement>
+  @ViewChild('chatInput') chatInput!: ElementRef<HTMLInputElement>
+
+  private typewriterBuffer: string[] = []
+  private typewriterActive = false
+
+  public get placeholder(): string {
+    return this.documentId
+      ? $localize`Ask a question about this document...`
+      : $localize`Ask a question about a document...`
+  }
+
+  ngOnInit(): void {
+    this.updateDocumentId(this.router.url)
+    this.router.events
+      .pipe(
+        filter((event) => event instanceof NavigationEnd),
+        map((event) => (event as NavigationEnd).url)
+      )
+      .subscribe((url) => {
+        this.updateDocumentId(url)
+      })
+  }
+
+  private updateDocumentId(url: string): void {
+    const docIdRe = url.match(/^\/documents\/(\d+)/)
+    this.documentId = docIdRe ? +docIdRe[1] : undefined
+  }
+
+  sendMessage(): void {
+    if (!this.input.trim()) return
+
+    const userMessage: ChatMessage = { role: 'user', content: this.input }
+    this.messages.push(userMessage)
+    this.scrollToBottom()
+
+    const assistantMessage: ChatMessage = {
+      role: 'assistant',
+      content: '',
+      isStreaming: true,
+    }
+    this.messages.push(assistantMessage)
+    this.loading = true
+
+    let lastPartialLength = 0
+
+    this.chatService.streamChat(this.documentId, this.input).subscribe({
+      next: (chunk) => {
+        const delta = chunk.substring(lastPartialLength)
+        lastPartialLength = chunk.length
+        this.enqueueTypewriter(delta, assistantMessage)
+      },
+      error: () => {
+        assistantMessage.content += '\n\n⚠️ Error receiving response.'
+        assistantMessage.isStreaming = false
+        this.loading = false
+      },
+      complete: () => {
+        assistantMessage.isStreaming = false
+        this.loading = false
+        this.scrollToBottom()
+      },
+    })
+
+    this.input = ''
+  }
+
+  enqueueTypewriter(chunk: string, message: ChatMessage): void {
+    if (!chunk) return
+
+    this.typewriterBuffer.push(...chunk.split(''))
+
+    if (!this.typewriterActive) {
+      this.typewriterActive = true
+      this.playTypewriter(message)
+    }
+  }
+
+  playTypewriter(message: ChatMessage): void {
+    if (this.typewriterBuffer.length === 0) {
+      this.typewriterActive = false
+      return
+    }
+
+    const nextChar = this.typewriterBuffer.shift()
+    message.content += nextChar
+    this.scrollToBottom()
+
+    setTimeout(() => this.playTypewriter(message), 10) // 10ms per character
+  }
+
+  private scrollToBottom(): void {
+    setTimeout(() => {
+      this.scrollAnchor?.nativeElement?.scrollIntoView({ behavior: 'smooth' })
+    }, 50)
+  }
+
+  public onOpenChange(open: boolean): void {
+    if (open) {
+      setTimeout(() => {
+        this.chatInput.nativeElement.focus()
+      }, 10)
+    }
+  }
+
+  public searchInputKeyDown(event: KeyboardEvent) {
+    if (event.key === 'Enter') {
+      event.preventDefault()
+      this.sendMessage()
+    }
+  }
+}