{
  "context": "A chat application needs a robust presence tracking system that maintains an accurate list of online users, handles initial state loading, processes all types of presence events including high-occupancy scenarios, and exposes hooks for UI integration.",
  "type": "weighted_checklist",
  "checklist": [
    {
      "name": "Map-based user tracking",
      "description": "Uses a Map (or equivalent dictionary) to store online users keyed by UUID, supporting add, remove, and lookup operations",
      "max_score": 10
    },
    {
      "name": "hereNow initialization",
      "description": "Has an initialize method that calls pubnub.hereNow() with includeUUIDs: true and includeState: true to populate the initial user list before relying on events",
      "max_score": 15
    },
    {
      "name": "Join handling",
      "description": "Handles 'join' events by adding the user to the map with their UUID and optional state",
      "max_score": 10
    },
    {
      "name": "Leave and timeout handling",
      "description": "Handles both 'leave' and 'timeout' events by removing the user from the map",
      "max_score": 10
    },
    {
      "name": "State-change handling",
      "description": "Handles 'state-change' events by updating the existing user's state in the map without removing them",
      "max_score": 10
    },
    {
      "name": "Interval event handling",
      "description": "Handles 'interval' events by processing batch arrays of join, leave, and timeout UUIDs from the event object",
      "max_score": 15
    },
    {
      "name": "Occupancy tracking",
      "description": "Tracks the occupancy count from each presence event's occupancy field and exposes it via a getter method",
      "max_score": 10
    },
    {
      "name": "Callback hooks exposed",
      "description": "Exposes overridable callback methods (e.g., onUserJoined, onUserLeft, onOccupancyChanged) that external code can set to react to presence changes",
      "max_score": 10
    },
    {
      "name": "withPresence subscription",
      "description": "Subscribes to the channel with withPresence: true (or receivePresenceEvents: true) to receive presence events",
      "max_score": 10
    }
  ]
}