Code Review & Refactor: fix SRP violations, remove global state, and make it concurrency-safe

Coding: Code review & refactor (SRP / concurrency / global variables) You are given a Python snippet that processes orders. The code has issues such as: SRP violation: one function does validation, pricing, persistence, and notifications. Global mutable state for counters/logging. Race conditions under concurrency (multiple threads processing orders), causing duplicated IDs, incorrect counters, and corrupted logs. Tasks: Identify at least 4 major issues and explain the risks. Refactor without changing external behavior: Remove global mutable state. Split responsibilities (validation, pricing, persistence, notification). Make it correct under multi-threaded concurrent processing (unique order IDs, accurate counts). I/O Input: first line integer n; next n lines are orders userId,amount. Output: count=<n> n lines of orderId=<id> (sorted ascending is fine) IDs must be globally unique. Constraints 1 <= n <= 20000 1 <= amount <= 1e9 Example Input: 3 u1,10 u2,20 u3,30 Output: count=3 orderId=100000 orderId=100001 orderId=100002 Example Input 1 u1,10 Output count=1 orderId=100000