# Phase 2 Implementation - Complete ✅

## Overview
Successfully implemented the Gateway Integration layer with parallel streaming, chat title generation, tab status indicators, and complete Zustand state management.

---

## ✅ Completed Components

### 1. **StorageManager** (`src/gateway/services/StorageManager.ts`)
**Purpose**: Unified interface for storage provider management

**Features**:
- Supports 3 modes: `local`, `papr`, `hybrid`
- Automatic provider initialization
- Message operations (save, load, load for LLM)
- Chat operations (create, update, delete, list, get)
- Summary operations (fetch, cache, save)
- Sync operations (mark synced, mark failed, get unsynced)
- Mode switching support

**Key Methods**:
```typescript
initialize(config: StorageConfig): Promise<void>
saveMessage(chatId: string, message: StoredMessage): Promise<void>
loadMessages(chatId: string, limit?: number, skip?: number): Promise<StoredMessage[]>
loadMessagesForLLM(chatId: string): Promise<any[]>
createChat(chatId: string, title?: string): Promise<void>
updateChat(chatId: string, updates: Partial<{ title: string }>): Promise<void>
getChat(chatId: string): Promise<ChatMetadata | null>
getChatStats(chatId: string): Promise<{ message_count, token_count, has_summary }>
fetchAndCacheSummary(chatId: string): Promise<StoredSummary | null>
```

---

### 2. **ChatSessionManager** (`src/gateway/services/ChatSessionManager.ts`)
**Purpose**: Manages parallel chat sessions for concurrent streaming

**Features**:
- One Mastra agent instance per chat
- Independent abort controllers per chat
- Supports Anthropic, OpenAI, Google providers
- Automatic agent creation/reuse
- Config change detection and agent recreation
- Session lifecycle management

**Key Methods**:
```typescript
getSession(chatId: string, config: AgentConfig): Promise<ChatSession>
abortSession(chatId: string): Promise<void>
clearSession(chatId: string): Promise<void>
isStreaming(chatId: string): boolean
setStreaming(chatId: string, isStreaming: boolean): void
getStreamingSessions(): ChatSession[]
```

**Parallel Streaming Architecture**:
- Each chat has isolated state in `Map<chatId, ChatSession>`
- Multiple chats can stream simultaneously without interference
- Per-chat abort controllers for independent cancellation

---

### 3. **TitleGenerationService** (`src/gateway/services/TitleGenerationService.ts`)
**Purpose**: Generate chat titles using gpt-5-mini-2025-08-07

**Features**:
- Uses `gpt-5-mini-2025-08-07` for fast, cheap title generation
- Maximum 40 characters
- Smart fallback truncation
- Removes common prefixes ("can you", "how do i", etc.)
- Title case formatting

**Key Methods**:
```typescript
generateTitle(firstMessage: string): Promise<string>
setApiKey(apiKey: string): void
```

**Example**:
```typescript
Input:  "Can you help me build a React component for user authentication?"
Output: "Build React Auth Component"
```

---

### 4. **AgentService** (Refactored - `src/gateway/services/AgentService.ts`)
**Purpose**: Main orchestrator for chat operations with parallel streaming

**Major Changes**:
- **BEFORE**: Single agent, single session, no persistence
- **AFTER**: Multiple parallel agents, full persistence, chat title generation, export

**New Architecture**:
```typescript
AgentService
├── StorageManager (local/papr/hybrid)
├── ChatSessionManager (parallel agents)
├── TitleGenerationService (gpt-5-mini-2025-08-07)
└── ChatExporter (~/Papr/ folder)
```

**Key Methods**:
```typescript
// Chat Management
createChat(chatId?: string, title?: string): Promise<string>
generateChatTitle(chatId: string, firstMessage: string): Promise<string>
updateChatTitle(chatId: string, title: string): Promise<void>
deleteChat(chatId: string): Promise<void>
listChats(): Promise<ChatMetadata[]>

// Streaming (with parallel support)
streamAgent(chatId: string, userMessage: string, config: AgentConfig): AsyncGenerator<StreamChunk & { chatId }>
stopStreaming(chatId: string): Promise<void>

// Chat Operations
getChatHistory(chatId: string): Promise<StoredMessage[]>
getChatStats(chatId: string): Promise<{ message_count, token_count, has_summary }>

// Session Management
getActiveSessions(): ChatSession[]
isStreaming(chatId: string): boolean
```

**Streaming Flow**:
1. Get/create chat session (parallel-safe)
2. Save user message to storage
3. Load message history (summary + recent messages)
4. Stream from Mastra agent with abort support
5. Yield chunks with `chatId` for frontend routing
6. Save assistant message to storage
7. Export chat to `~/Papr/` folder
8. Trigger summarization if needed (50K token threshold)

---

### 5. **Gateway WebSocket Handlers** (Updated)

#### **Agent Handlers** (`src/gateway/websocket/agent.ts`)
**New Endpoints**:
- `agent:stream` - Stream with chatId, parallel support
- `agent:stop` - Stop streaming for specific chat
- `agent:history` - Get chat history
- `agent:generate-title` - Generate title with gpt-5-mini-2025-08-07
- `agent:sessions` - List all active streaming sessions

**Parallel Streaming**:
- Each chunk includes `chatId` for frontend routing
- Multiple chats can stream concurrently
- Independent error handling per chat

#### **Chat Handlers** (`src/gateway/websocket/chat.ts`)
**Updated Endpoints**:
- `chat:list` - Uses StorageManager
- `chat:create` - Creates chat with optional chatId
- `chat:get` - Get single chat metadata
- `chat:update` - Update title
- `chat:delete` - Delete chat and clear session
- `chat:messages` - Get messages with pagination
- `chat:stats` - Get message/token counts

---

### 6. **Gateway Initialization** (`src/gateway/index.ts`)
**Updated**:
```typescript
// Initialize AgentService with storage config
const storageMode = process.env.STORAGE_MODE || 'hybrid';
const paprApiKey = process.env.PAPR_API_KEY;
const openaiApiKey = process.env.OPENAI_API_KEY;

await initializeAgentService({
  mode: storageMode,
  paprApiKey,
  openaiApiKey,
});
```

**Environment Variables**:
- `STORAGE_MODE`: `local` | `papr` | `hybrid` (default: `hybrid`)
- `PAPR_API_KEY`: Required for `papr` and `hybrid` modes
- `OPENAI_API_KEY`: Required for chat title generation
- `PAPR_BASE_URL`: Optional custom PAPR API URL

---

### 7. **Zustand Store Updates**

#### **Tab Store** (`ui/stores/tabStore.ts`)
**New Fields**:
```typescript
interface Tab {
  // ... existing fields
  isStreaming?: boolean;  // Blue pulsing dot
  hasUnread?: boolean;    // Green static dot
}
```

**New Methods**:
```typescript
setTabStreaming(tabId: string, isStreaming: boolean): void
setTabUnread(tabId: string, hasUnread: boolean): void
markTabAsRead(tabId: string): void
```

**Automatic Read Marking**:
- `switchToTab()` now calls `markTabAsRead()` automatically
- Only shows indicators on **inactive** tabs (not current tab)

#### **Chat Store** (`ui/stores/chatStore.ts`)
**Already Had**:
- `isStreaming` per chat
- `hasUnread` per chat
- Parallel streaming support
- Per-chat state management

---

### 8. **Tab Status Indicators**

#### **CSS** (`ui/components/Tabs/Tab.css`)
**Updated Colors** (Paprwork V1 style):
```css
/* Blue pulsing dot for streaming */
.tab__indicator--streaming {
  background: #007aff;  /* Blue */
  animation: pulse 2s ease-in-out infinite;
}

/* Green static dot for unread */
.tab__indicator--unread {
  background: #34c759;  /* Green */
}
```

#### **Component** (`ui/components/Tabs/Tab.tsx`)
**Updated Rendering**:
```tsx
{/* Only show on inactive tabs */}
{!isActive && (tab.isStreaming || tab.hasUnread) && (
  <span
    className={`tab__indicator ${tab.isStreaming ? 'tab__indicator--streaming' : 'tab__indicator--unread'}`}
    title={tab.isStreaming ? 'Streaming...' : 'Unread messages'}
  />
)}
```

**Behavior**:
- **Blue pulsing**: Chat is actively streaming in background
- **Green static**: Streaming finished while tab was in background
- **No dot**: Tab is active (current) or no activity
- **Auto-remove**: Dots disappear when tab becomes active

---

## 🎯 Key Features Delivered

### ✅ Parallel Streaming
- Multiple chats can stream concurrently
- Each chat has its own Mastra agent instance
- Independent abort controllers per chat
- No interference between streams
- Chunks tagged with `chatId` for frontend routing

### ✅ Chat Title Generation
- Uses gpt-5-mini-2025-08-07 for fast generation
- Triggers after first user message
- Maximum 40 characters
- Smart fallback truncation
- Removes common prefixes

### ✅ Tab Status Indicators
- Blue pulsing dot: Streaming
- Green static dot: Unread
- Only visible on inactive tabs
- Auto-clear when tab becomes active
- Paprwork V1 styling

### ✅ Full Persistence
- Three storage modes: local, PAPR, hybrid
- Message storage with sync status
- Chat metadata management
- Automatic export to `~/Papr/` folder
- Summary generation (50K token threshold)

### ✅ State Management
- Zustand stores for chat/tab state
- Per-chat streaming state
- Tab status management
- Automatic read marking

---

## 📊 Architecture Diagram

```
┌─────────────────────────────────────────────────────────────┐
│                         UI Layer                            │
│  ┌──────────────────┐  ┌──────────────────┐                │
│  │   Chat Store     │  │    Tab Store     │                │
│  │  - chatStates    │  │  - tabs[]        │                │
│  │  - isStreaming   │  │  - isStreaming   │                │
│  │  - hasUnread     │  │  - hasUnread     │                │
│  └──────────────────┘  └──────────────────┘                │
└─────────────────────────────────────────────────────────────┘
                            │
                    WebSocket Messages
                            │
┌─────────────────────────────────────────────────────────────┐
│                      Gateway Layer                          │
│  ┌──────────────────────────────────────────────────────┐   │
│  │                   AgentService                       │   │
│  │  ┌──────────────────────────────────────────────┐   │   │
│  │  │         ChatSessionManager                   │   │   │
│  │  │  Map<chatId, { agent, abortController }>    │   │   │
│  │  └──────────────────────────────────────────────┘   │   │
│  │  ┌──────────────────────────────────────────────┐   │   │
│  │  │          StorageManager                      │   │   │
│  │  │  Local / PAPR / Hybrid                       │   │   │
│  │  └──────────────────────────────────────────────┘   │   │
│  │  ┌──────────────────────────────────────────────┐   │   │
│  │  │      TitleGenerationService                  │   │   │
│  │  │  gpt-5-mini-2025-08-07                       │   │   │
│  │  └──────────────────────────────────────────────┘   │   │
│  └──────────────────────────────────────────────────────┘   │
└─────────────────────────────────────────────────────────────┘
                            │
                    Storage Providers
                            │
┌─────────────────────────────────────────────────────────────┐
│  ┌──────────────┐  ┌──────────────┐  ┌──────────────┐      │
│  │    Local     │  │     PAPR     │  │    Hybrid    │      │
│  │   SQLite     │  │    Memory    │  │   Both       │      │
│  │ better-sqlite│  │  @papr/memory│  │              │      │
│  └──────────────┘  └──────────────┘  └──────────────┘      │
└─────────────────────────────────────────────────────────────┘
```

---

## 🔄 Streaming Flow

```
User sends message → UI
         │
         ├─ WebSocket: agent:stream { chatId, message, config }
         │
         ▼
    AgentService.streamAgent(chatId, message, config)
         │
         ├─ 1. ChatSessionManager.getSession(chatId) → Get/create agent
         ├─ 2. StorageManager.saveMessage(userMsg)
         ├─ 3. StorageManager.loadMessagesForLLM() → Get context
         ├─ 4. agent.generate() with abort controller
         │    │
         │    ├─ Yield: { type: 'text-delta', text, chatId }
         │    ├─ Yield: { type: 'reasoning-delta', reasoning, chatId }
         │    ├─ Yield: { type: 'tool-call', toolCall, chatId }
         │    └─ Yield: { type: 'tool-result', toolResult, chatId }
         │
         ├─ 5. StorageManager.saveMessage(assistantMsg)
         ├─ 6. ChatExporter.exportChat() → ~/Papr/
         └─ 7. If > 50K tokens → fetchAndCacheSummary()
         
         ▼
    WebSocket: agent:chunk { chatId, type, content }
         │
         ▼
    UI updates chatStore for chatId
    UI updates tabStore indicators
```

---

## 🎨 Tab Status Behavior

### Scenario 1: Streaming in Active Tab
```
Tab: [Chat 1]  (active, blue pulsing)
→ User sees: No dot (tab is active)
→ Store: tab.isStreaming = true
```

### Scenario 2: Streaming Finishes in Background
```
Tab: [Chat 2]  (inactive, was streaming)
→ User sees: Green dot (unread)
→ Store: tab.isStreaming = false, tab.hasUnread = true
```

### Scenario 3: User Switches to Unread Tab
```
User clicks: [Chat 2]
→ switchToTab() calls markTabAsRead()
→ User sees: No dot (now active)
→ Store: tab.hasUnread = false
```

### Scenario 4: Multiple Chats Streaming
```
Tab: [Chat 1] (active, blue pulsing internally)
Tab: [Chat 2] (inactive, blue pulsing dot)
Tab: [Chat 3] (inactive, blue pulsing dot)
→ Parallel streams with independent sessions
```

---

## 📝 Usage Examples

### Create Chat with Title Generation
```typescript
// Frontend sends first message
ws.send(JSON.stringify({
  id: 'msg-123',
  type: 'agent:stream',
  payload: {
    chatId: 'chat-abc',
    message: 'How do I build a React component?',
    config: { provider: 'openai', model: 'gpt-5-mini-2025-08-07', ... }
  }
}));

// Backend generates title
const title = await agentService.generateChatTitle(
  'chat-abc',
  'How do I build a React component?'
);
// Title: "Build React Component"

// Update UI
ws.send(JSON.stringify({
  type: 'chat:title-updated',
  data: { chatId: 'chat-abc', title }
}));
```

### Stop Streaming
```typescript
// Frontend
ws.send(JSON.stringify({
  id: 'msg-456',
  type: 'agent:stop',
  payload: { chatId: 'chat-abc' }
}));

// Backend
await agentService.stopStreaming('chat-abc');
// Aborts only this chat's stream, others continue
```

### Tab Status Updates
```typescript
// When streaming starts
tabStore.setTabStreaming(tabId, true);

// When streaming finishes in background
if (tabId !== activeTabId) {
  tabStore.setTabUnread(tabId, true);
}

// When user switches to tab
tabStore.switchToTab(tabId); // Auto-calls markTabAsRead()
```

---

## 🚀 Next Steps

### Phase 3: UI Integration
1. Update ChatContainer to:
   - Use WebSocket `agent:stream` with chatId
   - Handle parallel streaming chunks
   - Trigger title generation after first message
   - Update tab indicators based on streaming state

2. Update TabBar to:
   - Show status indicators from tab object
   - Handle real-time updates from chatStore

3. Add IPC/WebSocket integration layer:
   - Message routing by chatId
   - Tab status synchronization
   - Title updates

### Phase 4: Native File Provider Extension (Future)
- Deeper Finder integration
- "Locations" section placement
- On-demand sync
- Sync status indicators
- Background operations

---

## ✅ Checklist

- [x] StorageManager with 3 modes
- [x] ChatSessionManager for parallel streaming
- [x] TitleGenerationService with GPT-5.2-mini
- [x] AgentService refactor
- [x] Gateway WebSocket handlers
- [x] Gateway initialization
- [x] Tab Store status management
- [x] Chat Store (already had parallel support)
- [x] Tab Status Indicator CSS
- [x] Tab Component rendering
- [x] Automatic read marking

---

## 🎉 Summary

Phase 2 implementation is **COMPLETE**. The foundation is now in place for:
- ✅ Parallel streaming across multiple chats
- ✅ Chat title generation with gpt-5-mini-2025-08-07
- ✅ Tab status indicators (blue streaming, green unread)
- ✅ Full persistence layer (local/PAPR/hybrid)
- ✅ Zustand state management
- ✅ WebSocket endpoints for chat operations

Ready to proceed with **Phase 3: UI Integration** to wire up the frontend components! 🚀
