Build Adaptive Rate Limiting Middleware for Flask API

Design a dynamic rate limiting middleware for a Flask API that automatically adjusts request thresholds based on server load and client behavior. Implement a sliding window algorithm that can track requests per IP, detect potential abuse patterns, and gracefully degrade service under high traffic. Include machine learning-based anomaly detection to distinguish between legitimate traffic spikes and potential DDoS attempts. Provide configuration options for custom rate limit rules and integrate comprehensive logging for security monitoring.