{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "https://nightscout.github.io/schemas/capability-snapshot.schema.json",
  "title": "CapabilitySnapshot",
  "description": "Point-in-time snapshot of what the controller can actually do right now",
  "type": "object",
  "required": ["snapshotId", "controllerInstanceId", "snapshotAt"],
  "properties": {
    "snapshotId": {
      "type": "string",
      "format": "uuid",
      "description": "Unique identifier for this snapshot"
    },
    "controllerInstanceId": {
      "type": "string",
      "description": "Reference to ControllerInstanceRegistration"
    },
    "connectivity": {
      "type": "object",
      "description": "Current connectivity status",
      "properties": {
        "pumpConnected": {
          "type": "boolean",
          "description": "Is pump currently connected"
        },
        "pumpLastContact": {
          "type": "string",
          "format": "date-time",
          "description": "Last successful communication with pump"
        },
        "pumpRSSI": {
          "type": "integer",
          "description": "Pump radio signal strength"
        },
        "cgmConnected": {
          "type": "boolean",
          "description": "Is CGM currently connected"
        },
        "cgmLastReading": {
          "type": "string",
          "format": "date-time",
          "description": "Timestamp of last CGM reading"
        },
        "internetConnected": {
          "type": "boolean",
          "description": "Is device online"
        }
      }
    },
    "automationState": {
      "type": "object",
      "description": "Current automation status",
      "properties": {
        "closedLoopEnabled": {
          "type": "boolean",
          "description": "Is closed-loop automation active"
        },
        "suspended": {
          "type": "boolean",
          "description": "Is insulin delivery suspended"
        },
        "suspendReason": {
          "type": "string",
          "description": "Why suspended (if applicable)"
        },
        "lastLoopTime": {
          "type": "string",
          "format": "date-time",
          "description": "When loop algorithm last ran"
        },
        "lastEnactTime": {
          "type": "string",
          "format": "date-time",
          "description": "When last delivery was enacted"
        }
      }
    },
    "effectiveLimits": {
      "type": "object",
      "description": "Current safety limits in effect",
      "properties": {
        "maxBasal": {
          "type": "number",
          "description": "Maximum basal rate allowed (U/hr)"
        },
        "maxBolus": {
          "type": "number",
          "description": "Maximum bolus allowed (U)"
        },
        "maxIOB": {
          "type": "number",
          "description": "Maximum IOB allowed (U)"
        },
        "minBG": {
          "type": "number",
          "description": "Minimum target BG"
        }
      }
    },
    "health": {
      "type": "object",
      "description": "Device health indicators",
      "properties": {
        "reservoirUnits": {
          "type": "number",
          "description": "Remaining insulin units in reservoir"
        },
        "reservoirLevel": {
          "type": "string",
          "enum": ["full", "adequate", "low", "critical"],
          "description": "Reservoir level category"
        },
        "batteryPercent": {
          "type": "integer",
          "minimum": 0,
          "maximum": 100,
          "description": "Pump battery percentage"
        },
        "phoneBatteryPercent": {
          "type": "integer",
          "minimum": 0,
          "maximum": 100,
          "description": "Controller device battery"
        },
        "podAge": {
          "type": "integer",
          "description": "Hours since pod was activated (for pod pumps)"
        },
        "podExpires": {
          "type": "string",
          "format": "date-time",
          "description": "When pod expires"
        },
        "cgmCalibrationStatus": {
          "type": "string",
          "enum": ["ok", "needed", "overdue", "na"],
          "description": "CGM calibration status"
        },
        "sensorAge": {
          "type": "integer",
          "description": "Hours since sensor was started"
        },
        "timeSyncHealth": {
          "type": "string",
          "enum": ["good", "drift", "unknown"],
          "description": "Clock synchronization status"
        }
      }
    },
    "degradedCapabilities": {
      "type": "array",
      "description": "Capabilities that are currently degraded or unavailable",
      "items": {
        "type": "object",
        "properties": {
          "capability": {
            "type": "string",
            "description": "Which capability is affected"
          },
          "reason": {
            "type": "string",
            "description": "Why it's degraded"
          },
          "since": {
            "type": "string",
            "format": "date-time"
          }
        }
      }
    },
    "snapshotAt": {
      "type": "string",
      "format": "date-time",
      "description": "When this snapshot was taken"
    },
    "validFor": {
      "type": "integer",
      "description": "How long this snapshot is valid (seconds)"
    }
  }
}