Design an Ad Click Aggregation System

Functional Requirements:

• Ingest ad click events in real-time from users.
• Aggregate click counts for each ad within a configurable time window (e.g., last M minutes).
• Provide an API to return the number of clicks for a specific ad within a given time range.
• Provide an API to return the top N most clicked ads within a specified time window.
• Support filtering of aggregated data by dimensions such as user_id, IP, or country.

Non-Functional Requirements:

• Scalability: System should handle high throughput (e.g., up to 1 billion clicks per day).
• Low Latency: Aggregated results should be available within a few minutes of event arrival.
• Fault Tolerance: System should recover from failures without data loss or duplication.
• Data Deduplication: Ensure duplicate click events are not double-counted.
• Monitoring: Track system health, latency, and throughput for operational visibility.