✨ chat history

src/renderer/components/AIChat/Chat.css

@@ -63,11 +63,6 @@
   line-height: 1.4;
 }
 
-/* Push Clear button to the far right inside the tab bar */
-.chat-tabs .chat-clear-btn {
-  margin-left: auto;
-}
-
 .chat-header {
   display: flex;
   align-items: center;
@@ -82,22 +77,111 @@
   flex-shrink: 0;
 }
 
-.chat-clear-btn {
+/* ── Chat sub-header (History link + New Chat button) ────────────── */
+.chat-subheader {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 5px 10px;
+  border-bottom: 1px solid var(--border);
+  flex-shrink: 0;
+}
+
+.chat-history-link {
+  background: none;
+  border: none;
+  color: var(--text-muted);
+  font-size: 10px;
+  font-weight: 700;
+  letter-spacing: 0.06em;
+  padding: 3px 0;
+  cursor: pointer;
+  transition: color 0.15s;
+  text-decoration: underline;
+  text-underline-offset: 2px;
+  text-decoration-color: transparent;
+}
+
+.chat-history-link:hover,
+.chat-history-link-active {
+  color: var(--text-primary);
+  text-decoration-color: currentColor;
+}
+
+.chat-new-btn {
   background: none;
   border: 1px solid var(--border);
   border-radius: 4px;
   color: var(--text-muted);
   font-size: 10px;
-  padding: 2px 7px;
+  font-weight: 700;
+  letter-spacing: 0.06em;
+  padding: 3px 8px;
   cursor: pointer;
   transition: color 0.15s, border-color 0.15s;
 }
 
-.chat-clear-btn:hover {
+.chat-new-btn:hover {
   color: var(--text-primary);
   border-color: var(--text-muted);
 }
 
+/* ── History list ────────────────────────────────────────────────── */
+.chat-history-list {
+  flex: 1;
+  overflow-y: auto;
+  padding: 8px;
+  display: flex;
+  flex-direction: column;
+  gap: 2px;
+}
+
+.chat-history-item {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 3px;
+  padding: 9px 11px;
+  border-radius: 6px;
+  background: none;
+  border: 1px solid transparent;
+  cursor: pointer;
+  text-align: left;
+  width: 100%;
+  transition: background 0.12s, border-color 0.12s;
+}
+
+.chat-history-item:hover {
+  background: var(--message-bg);
+}
+
+.chat-history-item-active {
+  border-color: var(--border);
+  background: var(--message-bg);
+}
+
+.chat-history-time {
+  font-size: 10px;
+  font-weight: 700;
+  letter-spacing: 0.08em;
+  text-transform: uppercase;
+  color: var(--accent);
+}
+
+.chat-history-summary {
+  font-size: 12px;
+  color: var(--text-muted);
+  line-height: 1.45;
+  overflow: hidden;
+  display: -webkit-box;
+  -webkit-line-clamp: 2;
+  -webkit-box-orient: vertical;
+}
+
+.chat-history-item-active .chat-history-summary {
+  color: var(--text-secondary);
+}
+
 /* ── Pending attachment indicator (between tab bar and messages) ─── */
 .chat-attachment-indicator {
   display: flex;

src/renderer/components/AIChat/ChatPanel.tsx

@@ -9,9 +9,23 @@ import './Chat.css'
 
 type TabId = 'chat' | 'feedback'
 
+function formatSessionTime(createdAt: number): string {
+  const date = new Date(createdAt)
+  const now = new Date()
+  const isToday = date.toDateString() === now.toDateString()
+  const yesterday = new Date(now)
+  yesterday.setDate(yesterday.getDate() - 1)
+  const isYesterday = date.toDateString() === yesterday.toDateString()
+  if (isToday) return date.toLocaleTimeString([], { hour: 'numeric', minute: '2-digit' })
+  if (isYesterday) return 'Yesterday'
+  return date.toLocaleDateString([], { month: 'short', day: 'numeric' })
+}
+
 export function ChatPanel(): JSX.Element {
   const {
     chatHistory,
+    chatSessionsByFile,
+    activeSessionIdByFile,
     isAILoading,
     aiError,
     activeFileContent,
@@ -26,14 +40,19 @@ export function ChatPanel(): JSX.Element {
     setAIError,
     setAnnotations,
     linkAnnotationsToMessage,
-    clearChat
+    newChat,
+    setActiveSession
   } = useEditorStore()
 
   const [tab, setTab] = useState<TabId>('chat')
+  const [showHistory, setShowHistory] = useState(false)
   const [pendingAttachmentCount, setPendingAttachmentCount] = useState(0)
   const scrollRef = useRef<HTMLDivElement>(null)
   const prevAnnotationCountRef = useRef(annotations.length)
 
+  // Collapse history when switching files
+  useEffect(() => { setShowHistory(false) }, [activeFilePath])
+
   // Auto-switch to Feedback tab the first time annotations appear (0 → >0)
   useEffect(() => {
     const prev = prevAnnotationCountRef.current
@@ -103,6 +122,12 @@ export function ChatPanel(): JSX.Element {
   const allAnnotationsForFile: TextAnnotation[] =
     (activeFilePath ? annotationsByFile[activeFilePath]?.annotations : undefined) ?? []
 
+  const sessions = (activeFilePath ? chatSessionsByFile[activeFilePath] : undefined) ?? []
+  const activeSessionId = activeFilePath ? activeSessionIdByFile[activeFilePath] : undefined
+
+  // Subheader is shown in the chat tab once there is at least one session
+  const showSubheader = tab === 'chat' && sessions.length > 0
+
   return (
     <div className="chat-panel">
       {/* ── Tab bar ── */}
@@ -122,15 +147,25 @@ export function ChatPanel(): JSX.Element {
             <span className="chat-tab-badge">{annotations.length}</span>
           )}
         </button>
-
-        {/* Clear button floated right, only visible in Chat tab */}
-        {tab === 'chat' && chatHistory.length > 0 && (
-          <button className="chat-clear-btn" onClick={clearChat} title="Clear conversation">
-            Clear
-          </button>
-        )}
       </div>
 
+      {/* ── Chat sub-header: History link + New Chat button ── */}
+      {showSubheader && (
+        <div className="chat-subheader">
+          <button
+            className={`chat-history-link${showHistory ? ' chat-history-link-active' : ''}`}
+            onClick={() => setShowHistory(v => !v)}
+          >
+            {showHistory ? 'Back to chat' : `History${sessions.length > 1 ? ` (${sessions.length})` : ''}`}
+          </button>
+          {!showHistory && chatHistory.length > 0 && (
+            <button className="chat-new-btn" onClick={newChat} title="Start a new conversation">
+              + New Chat
+            </button>
+          )}
+        </div>
+      )}
+
       {/* ── Pending-attachment indicator ── */}
       {pendingAttachmentCount > 0 && (
         <div className="chat-attachment-indicator">
@@ -142,6 +177,29 @@ export function ChatPanel(): JSX.Element {
       {/* ── Panel content ── */}
       {tab === 'feedback' ? (
         <FeedbackPanel />
+      ) : showHistory ? (
+        <div className="chat-history-list">
+          {[...sessions].reverse().map((session) => {
+            const isActive = session.id === activeSessionId
+            const firstUserMsg = session.messages.find(m => m.role === 'user')
+            const summary = firstUserMsg
+              ? firstUserMsg.content.slice(0, 80) + (firstUserMsg.content.length > 80 ? '…' : '')
+              : 'Empty conversation'
+            return (
+              <button
+                key={session.id}
+                className={`chat-history-item${isActive ? ' chat-history-item-active' : ''}`}
+                onClick={() => {
+                  setActiveSession(session.id)
+                  setShowHistory(false)
+                }}
+              >
+                <span className="chat-history-time">{formatSessionTime(session.createdAt)}</span>
+                <span className="chat-history-summary">{summary}</span>
+              </button>
+            )
+          })}
+        </div>
       ) : (
         <>
           <div className="chat-messages" ref={scrollRef}>

src/renderer/store/editorStore.ts

@@ -1,5 +1,5 @@
 import { create } from 'zustand'
-import type { FileNode, ChatMessage, TextAnnotation, AnalysisMode, RevisionMeta, AttachmentMeta } from '../types/editor'
+import type { FileNode, ChatMessage, ChatSession, TextAnnotation, AnalysisMode, RevisionMeta, AttachmentMeta } from '../types/editor'
 
 interface AnnotationFileState {
   mode: AnalysisMode
@@ -19,8 +19,9 @@ interface EditorState {
   setContent: (content: string) => void
   markSaved: () => void
 
-  // Chat - persisted per file path
+  // Chat - persisted per file path, multiple sessions per file
-  chatHistoryByFile: Record<string, ChatMessage[]>
+  chatSessionsByFile: Record<string, ChatSession[]>
+  activeSessionIdByFile: Record<string, string>
   chatHistory: ChatMessage[]
   isAILoading: boolean
   aiError: string | null
@@ -29,7 +30,8 @@ interface EditorState {
   appendToLastAssistantMessage: (chunk: string) => void
   setAILoading: (loading: boolean) => void
   setAIError: (error: string | null) => void
-  clearChat: () => void
+  newChat: () => void
+  setActiveSession: (sessionId: string) => void
 
   // Annotations (highlights in editor) — also persisted per file
   annotations: TextAnnotation[]
@@ -128,7 +130,10 @@ export const useEditorStore = create<EditorState>((set, get) => ({
   isDirty: false,
   setActiveFile: (path, content) => {
     const s = get()
-    const existing = s.chatHistoryByFile[path] ?? []
+    const sessions = s.chatSessionsByFile[path] ?? []
+    const activeId = s.activeSessionIdByFile[path]
+    const activeSession = sessions.find(sess => sess.id === activeId) ?? sessions[sessions.length - 1]
+    const existing = activeSession?.messages ?? []
     const savedAnnotationState = s.annotationsByFile[path]
     set({
       activeFilePath: path,
@@ -143,7 +148,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -151,7 +157,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
   setContent: (content) => set({ activeFileContent: content, isDirty: true }),
   markSaved: () => set({ isDirty: false }),
 
-  chatHistoryByFile: {},
+  chatSessionsByFile: {},
+  activeSessionIdByFile: {},
   chatHistory: [],
   isAILoading: false,
   aiError: null,
@@ -160,17 +167,30 @@ export const useEditorStore = create<EditorState>((set, get) => ({
     const msg: ChatMessage = { id: `user-${Date.now()}`, role: 'user', content: text, attachments }
     set((s) => {
       const history = [...s.chatHistory, msg]
-      const byFile = s.activeFilePath
+      if (!s.activeFilePath) return { chatHistory: history }
-        ? { ...s.chatHistoryByFile, [s.activeFilePath]: history }
+      let sessions = s.chatSessionsByFile[s.activeFilePath] ?? []
-        : s.chatHistoryByFile
+      let activeId = s.activeSessionIdByFile[s.activeFilePath]
-      return { chatHistory: history, chatHistoryByFile: byFile }
+      // If no session exists yet, create the first one
+      if (sessions.length === 0 || !activeId) {
+        const newSession: ChatSession = { id: `session-${Date.now()}`, createdAt: Date.now(), messages: history }
+        return {
+          chatHistory: history,
+          chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: [newSession] },
+          activeSessionIdByFile: { ...s.activeSessionIdByFile, [s.activeFilePath]: newSession.id }
+        }
+      }
+      const updatedSessions = sessions.map(sess =>
+        sess.id === activeId ? { ...sess, messages: history } : sess
+      )
+      return { chatHistory: history, chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: updatedSessions } }
     })
     scheduleSave(() => {
       const st = get()
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -180,10 +200,12 @@ export const useEditorStore = create<EditorState>((set, get) => ({
     const msg: ChatMessage = { id: `asst-${Date.now()}`, role: 'assistant', content: '' }
     set((s) => {
       const history = [...s.chatHistory, msg]
-      const byFile = s.activeFilePath
+      if (!s.activeFilePath) return { chatHistory: history }
-        ? { ...s.chatHistoryByFile, [s.activeFilePath]: history }
+      const activeId = s.activeSessionIdByFile[s.activeFilePath]
-        : s.chatHistoryByFile
+      const sessions = (s.chatSessionsByFile[s.activeFilePath] ?? []).map(sess =>
-      return { chatHistory: history, chatHistoryByFile: byFile }
+        sess.id === activeId ? { ...sess, messages: history } : sess
+      )
+      return { chatHistory: history, chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: sessions } }
     })
   },
 
@@ -194,10 +216,12 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       if (last?.role === 'assistant') {
         history[history.length - 1] = { ...last, content: last.content + chunk }
       }
-      const byFile = s.activeFilePath
+      if (!s.activeFilePath) return { chatHistory: history }
-        ? { ...s.chatHistoryByFile, [s.activeFilePath]: history }
+      const activeId = s.activeSessionIdByFile[s.activeFilePath]
-        : s.chatHistoryByFile
+      const sessions = (s.chatSessionsByFile[s.activeFilePath] ?? []).map(sess =>
-      return { chatHistory: history, chatHistoryByFile: byFile }
+        sess.id === activeId ? { ...sess, messages: history } : sess
+      )
+      return { chatHistory: history, chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: sessions } }
     })
   },
 
@@ -210,7 +234,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
         return {
           activeFilePath: st.activeFilePath,
           scrollPositions: st.scrollPositions,
-          chatHistoryByFile: st.chatHistoryByFile,
+          chatSessionsByFile: st.chatSessionsByFile,
+          activeSessionIdByFile: st.activeSessionIdByFile,
           annotationsByFile: st.annotationsByFile
         }
       })
@@ -218,24 +243,41 @@ export const useEditorStore = create<EditorState>((set, get) => ({
   },
   setAIError: (aiError) => set({ aiError }),
 
-  clearChat: () => {
+  newChat: () => {
     set((s) => {
-      const byFile = s.activeFilePath
+      if (!s.activeFilePath) return {}
-        ? { ...s.chatHistoryByFile, [s.activeFilePath]: [] }
+      const newSession: ChatSession = { id: `session-${Date.now()}`, createdAt: Date.now(), messages: [] }
-        : s.chatHistoryByFile
+      const existingSessions = s.chatSessionsByFile[s.activeFilePath] ?? []
-      return { chatHistory: [], chatHistoryByFile: byFile }
+      return {
+        chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: [...existingSessions, newSession] },
+        activeSessionIdByFile: { ...s.activeSessionIdByFile, [s.activeFilePath]: newSession.id },
+        chatHistory: []
+      }
     })
     scheduleSave(() => {
       const st = get()
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
   },
 
+  setActiveSession: (sessionId: string) => {
+    set((s) => {
+      if (!s.activeFilePath) return {}
+      const session = (s.chatSessionsByFile[s.activeFilePath] ?? []).find(sess => sess.id === sessionId)
+      if (!session) return {}
+      return {
+        activeSessionIdByFile: { ...s.activeSessionIdByFile, [s.activeFilePath]: sessionId },
+        chatHistory: session.messages
+      }
+    })
+  },
+
   annotations: [],
   annotationsByFile: {},
   setAnnotations: (annotations) => {
@@ -255,7 +297,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -273,7 +316,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -290,7 +334,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -316,7 +361,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -327,17 +373,20 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       const history = s.chatHistory.map(m =>
         m.id === messageId ? { ...m, annotationIds } : m
       )
-      const byFile = s.activeFilePath
+      if (!s.activeFilePath) return { chatHistory: history }
-        ? { ...s.chatHistoryByFile, [s.activeFilePath]: history }
+      const activeId = s.activeSessionIdByFile[s.activeFilePath]
-        : s.chatHistoryByFile
+      const sessions = (s.chatSessionsByFile[s.activeFilePath] ?? []).map(sess =>
-      return { chatHistory: history, chatHistoryByFile: byFile }
+        sess.id === activeId ? { ...sess, messages: history } : sess
+      )
+      return { chatHistory: history, chatSessionsByFile: { ...s.chatSessionsByFile, [s.activeFilePath]: sessions } }
     })
     scheduleSave(() => {
       const st = get()
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -361,7 +410,8 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       return {
         activeFilePath: st.activeFilePath,
         scrollPositions: st.scrollPositions,
-        chatHistoryByFile: st.chatHistoryByFile,
+        chatSessionsByFile: st.chatSessionsByFile,
+        activeSessionIdByFile: st.activeSessionIdByFile,
         annotationsByFile: st.annotationsByFile
       }
     })
@@ -402,8 +452,23 @@ export const useEditorStore = create<EditorState>((set, get) => ({
       if (data.scrollPositions && typeof data.scrollPositions === 'object') {
         patch.scrollPositions = data.scrollPositions as Record<string, number>
       }
-      if (data.chatHistoryByFile && typeof data.chatHistoryByFile === 'object') {
+      if (data.chatSessionsByFile && typeof data.chatSessionsByFile === 'object') {
-        patch.chatHistoryByFile = data.chatHistoryByFile as Record<string, ChatMessage[]>
+        patch.chatSessionsByFile = data.chatSessionsByFile as Record<string, ChatSession[]>
+        patch.activeSessionIdByFile = (data.activeSessionIdByFile as Record<string, string>) ?? {}
+      } else if (data.chatHistoryByFile && typeof data.chatHistoryByFile === 'object') {
+        // Migrate from old flat format — wrap each file's history in a single session
+        const legacy = data.chatHistoryByFile as Record<string, ChatMessage[]>
+        const sessions: Record<string, ChatSession[]> = {}
+        const activeIds: Record<string, string> = {}
+        for (const [path, messages] of Object.entries(legacy)) {
+          if (Array.isArray(messages) && messages.length > 0) {
+            const id = `session-migrated-${Date.now()}`
+            sessions[path] = [{ id, createdAt: Date.now(), messages }]
+            activeIds[path] = id
+          }
+        }
+        patch.chatSessionsByFile = sessions
+        patch.activeSessionIdByFile = activeIds
       }
       if (data.annotationsByFile && typeof data.annotationsByFile === 'object') {
         patch.annotationsByFile = data.annotationsByFile as Record<string, AnnotationFileState>

src/renderer/types/editor.ts

@@ -22,6 +22,12 @@ export interface ChatMessage {
   annotationIds?: string[] // IDs of suggestions this message produced
 }
 
+export interface ChatSession {
+  id: string
+  createdAt: number
+  messages: ChatMessage[]
+}
+
 export type AnnotationType = 'passive_voice' | 'consistency' | 'style' | 'critique' | 'custom'
 
 export interface TextAnnotation {