Design a Ride-Hailing Backend System

Design a **ride-hailing platform** backend.

Include:
1. Real-time location tracking service
2. Dispatching algorithm (matching riders/drivers)
3. Geospatial indexing (QuadTrees/Geohash)
4. Surge pricing engine
5. Trip lifecycle workflow
6. Payment & receipts
7. Driver/rider rating system
8. Fraud detection logic
9. High-availability + replication
10. Analytics pipeline for supply/demand