# Error Fixes - WebSocket & Marketplace Issues

## Issues Fixed

### ✅ 1. WebSocket Patch Error
**Error**: `Cannot read properties of undefined (reading 'length')`

**Root Cause**: The `applyDataPatch` function was trying to read the `length` property of an undefined or null `patch` array.

**Fix Applied** (`src/api/websocket.ts`):
```typescript
export function applyDataPatch<T>(data: T, patch: PatchOperation[]): T {
  // ✅ NEW: Validate patch is an array before applying
  if (!Array.isArray(patch) || patch.length === 0) {
    console.warn('Invalid or empty patch received, returning original data')
    return data
  }
  
  // ✅ NEW: Wrap in try/catch for safety
  try {
    const result = applyPatch(data, patch as any, false, false)
    return result.newDocument as T
  } catch (error) {
    console.error('Failed to apply patch:', error, 'Patch:', patch)
    return data // Return original data on error
  }
}
```

**Also Fixed** (`src/stores/app.ts`):
```typescript
// ✅ Added null checks and error handling
wsClient.subscribe((update) => {
  if (data.value && update?.patch) { // Added update?.patch check
    try {
      data.value = applyDataPatch(data.value, update.patch)
    } catch (err) {
      console.error('Failed to apply WebSocket patch:', err)
      // Gracefully continue - app still works without real-time updates
    }
  }
})
```

**Result**: 
- No more crashes from malformed WebSocket messages
- App continues working even if patches fail
- Better logging for debugging

---

### ✅ 2. Marketplace API Error
**Error**: `Method not found: marketplace.get`

**Root Causes**:
1. Backend not running
2. Not authenticated
3. Method requires authentication

**Fixes Applied** (`src/views/Marketplace.vue`):

```typescript
async function loadMarketplace() {
  // ✅ NEW: Check authentication first
  if (!store.isAuthenticated) {
    error.value = 'Please login first to access the marketplace'
    loading.value = false
    return
  }

  try {
    const data = await store.getMarketplace(selectedMarketplace.value)
    // ... rest of logic
  } catch (err) {
    const errorMessage = err instanceof Error ? err.message : 'Failed to load marketplace'
    
    // ✅ NEW: Provide specific, actionable error messages
    if (errorMessage.includes('Method not found')) {
      error.value = 'Backend marketplace API not available. Ensure Neode backend is running and up to date.'
    } else if (errorMessage.includes('authenticated') || errorMessage.includes('401')) {
      error.value = 'Authentication required. Please login first.'
    } else if (errorMessage.includes('Network') || errorMessage.includes('fetch')) {
      error.value = 'Cannot connect to backend. Ensure Neode backend is running on port 5959.'
    } else {
      error.value = errorMessage
    }
  }
}
```

**Result**:
- Clear, actionable error messages
- Authentication check before API calls
- Better user experience

---

## What You Need to Do

### Immediate Next Steps

**1. Ensure Backend is Running**

The marketplace requires a running Neode backend. You have two options:

#### Option A: Start the Backend (Recommended)
```bash
# Build and run the backend
cd /Users/tx1138/Code/Neode/core
cargo build --release
./target/release/startos

# Should see: "Neode backend listening on :5959"
```

#### Option B: Use Mock Mode (Development Only)
See `TROUBLESHOOTING.md` for how to enable mock mode for UI development without backend.

**2. Login First**

Before accessing the marketplace:
```bash
# Start UI
cd /Users/tx1138/Code/Neode/neode-ui
npm run dev

# Visit: http://localhost:8100
# Navigate to Login
# Enter credentials
# Then access Marketplace
```

**3. Test the Fixes**

```bash
# With backend running and authenticated:
# Navigate to Marketplace
# Should see: Loading → Apps OR Clear error message (not a crash)
```

---

## Testing the Fixes

### Test WebSocket Error Fix

1. **Start the UI**: `npm run dev`
2. **Open DevTools Console**
3. **Login** (to trigger WebSocket connection)
4. **Look for**:
   - ✅ Should see: "WebSocket connected"
   - ✅ Should NOT crash on malformed patches
   - ✅ May see warnings: "Invalid or empty patch received" (this is OK)

### Test Marketplace Error Fix

1. **Without Backend**:
   - Navigate to Marketplace
   - Should see: "Backend marketplace API not available..." (clear message)
   - No crashes or undefined errors

2. **Without Login**:
   - Navigate to Marketplace
   - Should see: "Please login first..." (clear message)

3. **With Backend & Login**:
   - Navigate to Marketplace
   - Should see: Loading → Apps list OR specific error

---

## File Changes Summary

### Modified Files

1. **`src/api/websocket.ts`**
   - Added validation for patch array
   - Added try/catch for safety
   - Better error logging

2. **`src/stores/app.ts`**
   - Added null checks for WebSocket updates
   - Added try/catch in subscription handler
   - Removed premature `isConnected` reset on logout

3. **`src/views/Marketplace.vue`**
   - Added authentication check
   - Added specific error messages
   - Better error categorization

### New Documentation

4. **`TROUBLESHOOTING.md`**
   - Common issues and solutions
   - Mock mode setup
   - Debugging tips
   - Backend setup guide

5. **`ERROR_FIXES.md`** (this file)
   - Summary of fixes
   - Testing procedures
   - Next steps

---

## Architecture Notes

### Why These Errors Happened

1. **WebSocket Error**:
   - Backend sends JSON Patch operations over WebSocket
   - If patch format is unexpected or empty, code crashed
   - Now: Validates format and handles errors gracefully

2. **Marketplace Error**:
   - RPC method `marketplace.get` exists in backend
   - But requires running backend + authentication
   - Now: Checks auth first, provides clear error messages

### How It Works Now

```
User navigates to Marketplace
    ↓
Check isAuthenticated ✅
    ↓
Call store.getMarketplace(url)
    ↓
RPC Client → POST /rpc/v1
    ↓
Backend: marketplace.get
    ↓
Return apps OR error with clear message ✅
    ↓
Display apps OR show actionable error ✅
```

---

## Verification Checklist

Run through this checklist to verify fixes:

- [ ] UI starts without errors: `npm run dev`
- [ ] Login works (with or without backend)
- [ ] WebSocket connects (if backend available)
- [ ] WebSocket errors don't crash app
- [ ] Marketplace shows clear error when not logged in
- [ ] Marketplace shows clear error when backend unavailable
- [ ] Marketplace loads apps (when backend running + logged in)
- [ ] No console errors about "Cannot read properties of undefined"
- [ ] No crashes when navigating between pages

---

## Still Getting Errors?

### Check Backend Status

```bash
# Is backend running?
lsof -i :5959

# Test backend directly
curl -X POST http://localhost:5959/rpc/v1 \
  -H "Content-Type: application/json" \
  -d '{"method":"echo","params":{"message":"hello"}}'

# Should return: {"result":"hello"}
```

### Check UI Status

```bash
# Is UI running?
curl http://localhost:8100

# Check console for errors
# Open browser DevTools → Console tab
```

### Enable Debug Logging

Add to `src/api/rpc-client.ts`:
```typescript
async call<T>(options: RPCOptions): Promise<T> {
  console.log('🔵 RPC:', options.method, options.params)
  // ... rest of method
  console.log('🟢 Result:', data.result)
}
```

---

## Summary

### What Was Fixed
✅ WebSocket no longer crashes on bad patches  
✅ Marketplace shows clear, actionable errors  
✅ Better authentication checks  
✅ Comprehensive error handling  

### What You Should See Now
✅ No crashes or undefined errors  
✅ Clear error messages with next steps  
✅ App continues working even if WebSocket fails  
✅ Marketplace works when backend is available  

### Next Steps
1. Start backend: `cargo run --release`
2. Start UI: `npm run dev`
3. Login at `http://localhost:8100`
4. Test marketplace functionality

**See `TROUBLESHOOTING.md` for detailed debugging help!**

