feat: Phase 5 - citations, source highlighting, and UI polish

ui/src/App.tsx

@@ -2,7 +2,8 @@ import { useState, useRef, useEffect } from 'react'
 import './App.css'
 import MessageList from './components/MessageList'
 import ChatInput from './components/ChatInput'
-import { useChatStream } from './hooks/useChatStream'
+import CitationsPanel from './components/CitationsPanel'
+import { useChatStream, Citation } from './hooks/useChatStream'
 
 export interface Message {
   role: 'user' | 'assistant'
@@ -13,15 +14,13 @@ function App() {
   const [messages, setMessages] = useState<Message[]>([])
   const [input, setInput] = useState('')
   const [isLoading, setIsLoading] = useState(false)
+  const [citations, setCitations] = useState<Citation[]>([])
+  const [showCitations, setShowCitations] = useState(false)
   const messagesEndRef = useRef<HTMLDivElement>(null)
   const { sendMessage } = useChatStream()
 
-  const scrollToBottom = () => {
-    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' })
-  }
-
   useEffect(() => {
-    scrollToBottom()
+    messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' })
   }, [messages])
 
   const handleSend = async () => {
@@ -31,24 +30,37 @@ function App() {
     setInput('')
     setMessages(prev => [...prev, { role: 'user', content: userMessage }])
     setIsLoading(true)
+    setCitations([])
+    setShowCitations(false)
 
     let assistantContent = ''
     
-    await sendMessage(userMessage, (chunk) => {
-      assistantContent += chunk
-      setMessages(prev => {
-        const newMessages = [...prev]
-        const lastMsg = newMessages[newMessages.length - 1]
-        if (lastMsg?.role === 'assistant') {
-          lastMsg.content = assistantContent
-        } else {
-          newMessages.push({ role: 'assistant', content: assistantContent })
-        }
-        return newMessages
-      })
+    await sendMessage(userMessage, {
+      onChunk: (chunk) => {
+        assistantContent += chunk
+        setMessages(prev => {
+          const newMessages = [...prev]
+          const lastMsg = newMessages[newMessages.length - 1]
+          if (lastMsg?.role === 'assistant') {
+            lastMsg.content = assistantContent
+          } else {
+            newMessages.push({ role: 'assistant', content: assistantContent })
+          }
+          return newMessages
+        })
+      },
+      onCitations: (newCitations) => {
+        setCitations(newCitations)
+        setShowCitations(newCitations.length > 0)
+      },
+      onDone: () => {
+        setIsLoading(false)
+      },
+      onError: (error) => {
+        console.error('Stream error:', error)
+        setIsLoading(false)
+      }
     })
-
-    setIsLoading(false)
   }
 
   const handleKeyDown = (e: React.KeyboardEvent) => {
@@ -76,6 +88,11 @@ function App() {
           disabled={isLoading}
         />
       </footer>
+      <CitationsPanel
+        citations={citations}
+        isOpen={showCitations}
+        onClose={() => setShowCitations(false)}
+      />
     </div>
   )
 }

ui/src/components/CitationsPanel.css

@@ -0,0 +1,124 @@
+/* CitationsPanel.css */
+.citations-overlay {
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  background: rgba(0, 0, 0, 0.5);
+  z-index: 100;
+  border: none;
+  width: 100%;
+  cursor: pointer;
+}
+
+.citations-panel {
+  position: fixed;
+  top: 0;
+  right: 0;
+  width: 400px;
+  height: 100vh;
+  background: var(--bg-secondary);
+  border-left: 1px solid var(--border);
+  z-index: 101;
+  display: flex;
+  flex-direction: column;
+  animation: slideIn 0.2s ease-out;
+}
+
+@keyframes slideIn {
+  from {
+    transform: translateX(100%);
+  }
+  to {
+    transform: translateX(0);
+  }
+}
+
+.citations-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 16px 20px;
+  border-bottom: 1px solid var(--border);
+}
+
+.citations-header h3 {
+  margin: 0;
+  font-size: 16px;
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.close-button {
+  background: none;
+  border: none;
+  color: var(--text-secondary);
+  font-size: 24px;
+  cursor: pointer;
+  padding: 0 4px;
+  line-height: 1;
+}
+
+.close-button:hover {
+  color: var(--text-primary);
+}
+
+.citations-list {
+  flex: 1;
+  overflow-y: auto;
+  padding: 16px 20px;
+}
+
+.citation-item {
+  display: flex;
+  gap: 12px;
+  padding: 16px;
+  margin-bottom: 12px;
+  background: var(--bg-tertiary);
+  border-radius: 8px;
+  border: 1px solid var(--border);
+}
+
+.citation-number {
+  flex-shrink: 0;
+  font-weight: 600;
+  color: var(--accent-primary);
+  font-size: 14px;
+}
+
+.citation-content {
+  flex: 1;
+  min-width: 0;
+}
+
+.citation-source {
+  font-size: 12px;
+  color: var(--text-secondary);
+  margin-bottom: 8px;
+  word-break: break-all;
+}
+
+.citation-text {
+  font-size: 14px;
+  color: var(--text-primary);
+  line-height: 1.5;
+  white-space: pre-wrap;
+  word-wrap: break-word;
+}
+
+.citation-tags {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 6px;
+  margin-top: 12px;
+}
+
+.citation-tag {
+  font-size: 11px;
+  padding: 2px 8px;
+  background: var(--bg-secondary);
+  color: var(--text-secondary);
+  border-radius: 4px;
+  border: 1px solid var(--border);
+}

ui/src/components/CitationsPanel.tsx

@@ -0,0 +1,47 @@
+import { Citation } from '../hooks/useChatStream'
+import './CitationsPanel.css'
+
+interface CitationsPanelProps {
+  citations: Citation[]
+  isOpen: boolean
+  onClose: () => void
+}
+
+export default function CitationsPanel({ citations, isOpen, onClose }: CitationsPanelProps) {
+  if (!isOpen || citations.length === 0) return null
+
+  return (
+    <>
+      <button
+        type="button"
+        className="citations-overlay"
+        onClick={onClose}
+        aria-label="Close citations panel"
+      />
+      <aside className="citations-panel">
+        <div className="citations-header">
+          <h3>Sources</h3>
+          <button type="button" className="close-button" onClick={onClose}>×</button>
+        </div>
+        <div className="citations-list">
+          {citations.map((citation, index) => (
+            <div key={citation.id} className="citation-item">
+              <div className="citation-number">[{index + 1}]</div>
+              <div className="citation-content">
+                <div className="citation-source">{citation.citation}</div>
+                <div className="citation-text">{citation.text}</div>
+                {citation.tags && citation.tags.length > 0 && (
+                  <div className="citation-tags">
+                    {citation.tags.map(tag => (
+                      <span key={tag} className="citation-tag">{tag}</span>
+                    ))}
+                  </div>
+                )}
+              </div>
+            </div>
+          ))}
+        </div>
+      </aside>
+    </>
+  )
+}

ui/src/hooks/useChatStream.ts

@@ -2,13 +2,33 @@ import { useState } from 'react'
 
 const API_BASE = '/api'
 
+export interface Citation {
+  id: string
+  text: string
+  source_file: string
+  source_directory: string
+  section: string | null
+  date: string | null
+  tags: string[]
+  citation: string
+}
+
+export interface StreamCallbacks {
+  onChunk: (chunk: string) => void
+  onCitations?: (citations: Citation[]) => void
+  onError?: (error: string) => void
+  onDone?: () => void
+}
+
 export function useChatStream() {
   const [sessionId, setSessionId] = useState<string | null>(null)
 
   const sendMessage = async (
     message: string,
-    onChunk: (chunk: string) => void
+    callbacks: StreamCallbacks
   ): Promise<void> => {
+    const { onChunk, onCitations, onError, onDone } = callbacks
+
     const response = await fetch(`${API_BASE}/chat`, {
       method: 'POST',
       headers: {
@@ -18,6 +38,7 @@ export function useChatStream() {
         message,
         session_id: sessionId,
         stream: true,
+        use_rag: true,
       }),
     })
 
@@ -50,15 +71,33 @@ export function useChatStream() {
           if (line.startsWith('data: ')) {
             const data = line.slice(6)
             if (data === '[DONE]') {
+              onDone?.()
               return
             }
             try {
               const parsed = JSON.parse(data)
-              if (parsed.content) {
-                onChunk(parsed.content)
+              switch (parsed.type) {
+                case 'chunk':
+                  if (parsed.content) {
+                    onChunk(parsed.content)
+                  }
+                  break
+                case 'citations':
+                  if (parsed.citations && onCitations) {
+                    onCitations(parsed.citations as Citation[])
+                  }
+                  break
+                case 'error':
+                  if (parsed.message && onError) {
+                    onError(parsed.message)
+                  }
+                  break
+                case 'done':
+                  onDone?.()
+                  return
               }
             } catch {
-              // Ignore parse errors
+              // Ignore parse errors for non-JSON data
             }
           }
         }