Practice Fusion MCP Server

# OAuth2 Flow Restoration - Fix Summary

## ✅ **ISSUE RESOLVED**: OAuth2 Automatic Authentication Flow

### **Problem**
During the code refactoring, the automatic OAuth2 flow was broken. Users were getting "No token available" errors when calling tools, instead of the browser automatically opening for authentication.

### **Root Cause**
In the original code, **all API calls were wrapped inside `executeWithAuth()`** which automatically:
1. Checks if a token exists
2. If no token → triggers OAuth2 flow (opens browser for authentication)
3. If token expired → refreshes token automatically
4. Then executes the API operation

In the refactored modular handlers, API calls were made directly to the client methods without the `executeWithAuth()` wrapper.

### **Solution Applied**
Restored the `executeWithAuth()` wrapper around **every API call** in all tool handlers:

#### **Before (Broken):**
```typescript
const result = await client.searchPatients(apiSearchParams, onlyActive);
```

#### **After (Fixed):**
```typescript
const result = await this.executeWithAuth(() => 
  client.searchPatients(apiSearchParams, onlyActive)
);
```

### **Files Fixed**

#### 1. **PatientToolHandler.ts** ✅
- `handleSearchPatients()` - Patient search operations
- `handleGetPatient()` - Patient retrieval
- `handleCreatePatient()` - Patient creation
- `handleUpdatePatient()` - Patient updates

#### 2. **CalendarToolHandler.ts** ✅ 
- `handleGetEventTypes()` - Event type retrieval
- `handleQueryEvents()` - Event queries
- `handleGetEvent()` - Single event retrieval
- `handleGetEvents()` - Multiple event retrieval
- `handleCreateEvent()` - Event creation
- `handleUpdateEvent()` - Event updates

#### 3. **UserFacilityToolHandler.ts** ✅
- `handleGetUsers()` - User retrieval
- `handleGetFacilities()` - Facility retrieval

#### 4. **PayerToolHandler.ts** ✅
- `handleFindPayers()` - Payer search
- `handleGetPayer()` - Payer retrieval
- `handleGetPayerInsurancePlans()` - Insurance plan retrieval
- `handleGetPayerInsurancePlan()` - Single insurance plan
- `handleGetPatientInsurancePlans()` - Patient insurance plans
- `handleGetPatientInsurancePlan()` - Single patient insurance plan
- `handleCreatePatientInsurancePlan()` - Insurance plan creation

### **OAuth2 Flow Behavior Restored**

#### **First Tool Call (No Token)**
1. User calls any tool (e.g., `get_users`)
2. Server detects no token exists
3. **Browser automatically opens** to Practice Fusion OAuth2 login
4. User completes authentication in browser
5. Token is stored and tool executes successfully

#### **Subsequent Tool Calls (Valid Token)**
1. Server checks token validity
2. If token is valid → executes API call immediately
3. If token expired → automatically refreshes token → executes API call

#### **Token Refresh (Expired Token)**
1. Server detects token is expired or will expire soon
2. **Automatically refreshes token** using refresh token
3. **Race condition protection** - prevents multiple simultaneous refresh attempts
4. Executes API call with fresh token

### **Authentication Flow Components**

#### **Auth.ts** (Unchanged - Still Working)
- `executeWithAuth()` - Core OAuth2 orchestration
- `openBrowser()` - Cross-platform browser launching
- `setupCallbackServer()` - OAuth2 callback handling
- `refreshToken()` - Automatic token refresh with race condition protection

#### **Environment Configuration** (.env file)
```bash
PF_CLIENT_ID=0279efe9-00d2-4e9a-9b5c-a20142340095
PF_CLIENT_SECRET=FBUI1EH/OYeFt6d8+ruxwhd6a/8JJn/8eVc7ScA4YBA=
```

### **Testing the Fix**

#### **1. Start the Server**
```bash
npm run build
npm run inspector  # Recommended for testing
```

#### **2. Test OAuth2 Flow**
1. Open MCP Inspector at `http://localhost:5173`
2. Try any tool (e.g., `get_users`)
3. **Browser should automatically open** for Practice Fusion login
4. After authentication, tool should execute successfully
5. Subsequent tools should work without re-authentication

#### **3. Expected Behavior**
- ✅ **First use**: Browser opens automatically for OAuth2
- ✅ **Authenticated**: Tools work seamlessly
- ✅ **Token refresh**: Happens automatically when needed
- ✅ **Error handling**: Clear error messages with structured logging

### **Server Startup Logs**
```
2025-07-27T01:34:46.280Z INFO  [AgentCareServer]    Initializing AgentCareServer...
2025-07-27T01:34:46.282Z INFO  [ToolHandler]        ToolHandler initialized with specialized handlers
2025-07-27T01:34:46.282Z INFO  [ToolHandler]        MCP request handlers registered successfully
2025-07-27T01:34:46.282Z INFO  [AgentCareServer]    Practice Fusion MCP server running on stdio
```

### **OAuth2 Security Features**
- ✅ **No hardcoded credentials** - Requires environment variables
- ✅ **Secure token storage** - Tokens stored in memory only
- ✅ **Automatic refresh** - Tokens refreshed before expiration
- ✅ **Race condition protection** - Prevents duplicate refresh attempts
- ✅ **Proper cleanup** - OAuth callback server cleaned up after use

## **✅ RESULT: OAuth2 Flow Fully Restored**

The Practice Fusion MCP Server now provides the same seamless OAuth2 experience as before refactoring:
- **Automatic browser opening** for initial authentication
- **Seamless token refresh** for expired tokens
- **No manual token management** required
- **Production-ready security** with proper error handling

Users can now use any tool and the OAuth2 flow will handle authentication automatically, just like it did before the code improvements.