# Phase 3: Enhanced Error Handling - COMPLETE

**Status**: ✅ Fully Implemented
**Date**: 2025-01-07

## Overview

Phase 3 adds comprehensive error handling improvements to the Sacred Pipeline, including transaction status polling, enhanced error sanitization, and client-side rate limiting for submission creation.

## Components Implemented

### 1. Transaction Status Polling Endpoint

**Edge Function**: `check-transaction-status`
**Purpose**: Allows clients to poll the status of moderation transactions using idempotency keys

**Features**:
- Query transaction status by idempotency key
- Returns detailed status information (pending, processing, completed, failed, expired)
- User authentication and authorization (users can only check their own transactions)
- Structured error responses
- Comprehensive logging

**Usage**:
```typescript
const { data, error } = await supabase.functions.invoke('check-transaction-status', {
  body: { idempotencyKey: 'approval_submission123_...' }
});

// Response includes:
// - status: 'pending' | 'processing' | 'completed' | 'failed' | 'expired' | 'not_found'
// - createdAt, updatedAt, expiresAt
// - attempts, lastError (if failed)
// - action, submissionId
```

**API Endpoints**:
- `POST /check-transaction-status` - Check status by idempotency key
- Requires: Authentication header
- Returns: StatusResponse with transaction details

### 2. Error Sanitizer

**File**: `src/lib/errorSanitizer.ts`
**Purpose**: Removes sensitive information from error messages before display or logging

**Sensitive Patterns Detected**:
- Authentication tokens (Bearer, JWT, API keys)
- Database connection strings (PostgreSQL, MySQL)
- Internal IP addresses
- Email addresses in error messages
- UUIDs (internal IDs)
- File paths (Unix & Windows)
- Stack traces with file paths
- SQL queries revealing schema

**User-Friendly Replacements**:
- Database constraint errors → "This item already exists", "Required field missing"
- Auth errors → "Session expired. Please log in again"
- Network errors → "Service temporarily unavailable"
- Rate limiting → "Rate limit exceeded. Please wait before trying again"
- Permission errors → "Access denied"

**Functions**:
- `sanitizeErrorMessage(error, context?)` - Main sanitization function
- `containsSensitiveData(message)` - Check if message has sensitive data
- `sanitizeErrorForLogging(error)` - Sanitize for external logging
- `createSafeErrorResponse(error, fallbackMessage?)` - Create user-safe error response

**Examples**:
```typescript
import { sanitizeErrorMessage } from '@/lib/errorSanitizer';

try {
  // ... operation
} catch (error) {
  const safeMessage = sanitizeErrorMessage(error, {
    action: 'park_creation',
    userId: user.id
  });
  
  toast({
    title: 'Error',
    description: safeMessage,
    variant: 'destructive'
  });
}
```

### 3. Submission Rate Limiting

**File**: `src/lib/submissionRateLimiter.ts`
**Purpose**: Client-side rate limiting to prevent submission abuse and accidental duplicates

**Rate Limits**:
- **Per Minute**: 5 submissions maximum
- **Per Hour**: 20 submissions maximum
- **Cooldown**: 60 seconds after exceeding limits

**Features**:
- In-memory rate limit tracking (per session)
- Automatic timestamp cleanup
- User-specific limits
- Cooldown period after limit exceeded
- Detailed logging

**Integration**: Applied to all submission functions in `entitySubmissionHelpers.ts`:
- `submitParkCreation`
- `submitParkUpdate`
- `submitRideCreation`
- `submitRideUpdate`
- Composite submissions

**Functions**:
- `checkSubmissionRateLimit(userId, config?)` - Check if user can submit
- `recordSubmissionAttempt(userId)` - Record a submission (called after success)
- `getRateLimitStatus(userId)` - Get current rate limit status
- `clearUserRateLimit(userId)` - Clear limits (admin/testing)

**Usage**:
```typescript
// In entitySubmissionHelpers.ts
function checkRateLimitOrThrow(userId: string, action: string): void {
  const rateLimit = checkSubmissionRateLimit(userId);
  
  if (!rateLimit.allowed) {
    throw new Error(sanitizeErrorMessage(rateLimit.reason));
  }
}

// Called at the start of every submission function
export async function submitParkCreation(data, userId) {
  checkRateLimitOrThrow(userId, 'park_creation');
  // ... rest of submission logic
}
```

**Response Example**:
```typescript
{
  allowed: false,
  reason: 'Too many submissions in a short time. Please wait 60 seconds',
  retryAfter: 60
}
```

## Architecture Adherence

✅ **No JSON/JSONB**: Error sanitizer operates on strings, rate limiter uses in-memory storage
✅ **Relational**: Transaction status queries the `idempotency_keys` table
✅ **Type Safety**: Full TypeScript types for all interfaces
✅ **Logging**: Comprehensive structured logging for debugging

## Security Benefits

1. **Sensitive Data Protection**: Error messages no longer expose internal details
2. **Rate Limit Protection**: Prevents submission flooding and abuse
3. **Transaction Visibility**: Users can check their own transaction status safely
4. **Audit Trail**: All rate limit events logged for security monitoring

## Error Flow Integration

```
User Action
    ↓
Rate Limit Check ────→ Block if exceeded
    ↓
Submission Creation
    ↓
Error Occurs ────→ Sanitize Error Message
    ↓
Display to User (Safe Message)
    ↓
Log to System (Detailed, Sanitized)
```

## Testing Checklist

- [x] Edge function deploys successfully
- [x] Transaction status polling works with valid keys
- [x] Transaction status returns 404 for invalid keys
- [x] Users cannot access other users' transaction status
- [x] Error sanitizer removes sensitive patterns
- [x] Error sanitizer provides user-friendly messages
- [x] Rate limiter blocks after per-minute limit
- [x] Rate limiter blocks after per-hour limit
- [x] Rate limiter cooldown period works
- [x] Rate limiting applied to all submission functions
- [x] Sanitized errors logged correctly

## Related Files

### Core Implementation
- `supabase/functions/check-transaction-status/index.ts` - Transaction polling endpoint
- `src/lib/errorSanitizer.ts` - Error message sanitization
- `src/lib/submissionRateLimiter.ts` - Client-side rate limiting
- `src/lib/entitySubmissionHelpers.ts` - Integrated rate limiting

### Dependencies
- `src/lib/idempotencyLifecycle.ts` - Idempotency key lifecycle management
- `src/lib/logger.ts` - Structured logging
- `supabase/functions/_shared/logger.ts` - Edge function logging

## Performance Considerations

1. **In-Memory Storage**: Rate limiter uses Map for O(1) lookups
2. **Automatic Cleanup**: Old timestamps removed on each check
3. **Minimal Overhead**: Pattern matching optimized with pre-compiled regexes
4. **Database Queries**: Transaction status uses indexed lookup on idempotency_keys.key

## Future Enhancements

Potential improvements for future phases:

1. **Persistent Rate Limiting**: Store rate limits in database for cross-session tracking
2. **Dynamic Rate Limits**: Adjust limits based on user reputation/role
3. **Advanced Sanitization**: Context-aware sanitization based on error types
4. **Error Pattern Learning**: ML-based detection of new sensitive patterns
5. **Transaction Webhooks**: Real-time notifications when transactions complete
6. **Rate Limit Dashboard**: Admin UI to view and manage rate limits

## API Reference

### Check Transaction Status

**Endpoint**: `POST /functions/v1/check-transaction-status`

**Request**:
```json
{
  "idempotencyKey": "approval_submission_abc123_..."
}
```

**Response** (200 OK):
```json
{
  "status": "completed",
  "createdAt": "2025-01-07T10:30:00Z",
  "updatedAt": "2025-01-07T10:30:05Z",
  "expiresAt": "2025-01-08T10:30:00Z",
  "attempts": 1,
  "action": "approval",
  "submissionId": "abc123",
  "completedAt": "2025-01-07T10:30:05Z"
}
```

**Response** (404 Not Found):
```json
{
  "status": "not_found",
  "error": "Transaction not found. It may have expired or never existed."
}
```

**Response** (401/403):
```json
{
  "error": "Unauthorized",
  "status": "not_found"
}
```

## Migration Notes

No database migrations required for this phase. All functionality is:
- Edge function (auto-deployed)
- Client-side utilities (imported as needed)
- Integration into existing submission functions

## Monitoring

Key metrics to monitor:

1. **Rate Limit Events**: Track users hitting limits
2. **Sanitization Events**: Count messages requiring sanitization
3. **Transaction Status Queries**: Monitor polling frequency
4. **Error Patterns**: Identify common sanitized error types

Query examples in admin dashboard:
```sql
-- Rate limit violations (from logs)
SELECT COUNT(*) FROM request_metadata
WHERE error_message LIKE '%Rate limit exceeded%'
GROUP BY DATE(created_at);

-- Transaction status queries
-- (Check edge function logs for check-transaction-status)
```

---

**Phase 3 Status**: ✅ Complete
**Next Phase**: Phase 4 or additional enhancements as needed