White-Box SSD for View Pollutant Map UC

@startuml
title ViewPollutantMap
actor Traveler

box Front-End
  participant "System\n Android Cell Phone" as Android
end box

box Database Hook
  participant Webhook
end box

box Back-End
  participant SensorController
  participant SensorService
  participant CapturedPollutantProvider
  participant SensorProvider
  participant WaypointValidator
end box

box Database
  participant Sensor as Sensors
  participant CapturedPollutant as CapturedPollutants
end box

Traveler -> Android: selectMapView
Android ->> Webhook : set up listener
Android ->> Android : set up locationListener
note right: the location listener triggers anytime\nthe traveler's geolocation updates
Android -->> Traveler : map view

opt if location disabled
  Android -> Traveler: promptForLocation()
  alt if user allows
    Traveler -> Android: selectAllow()
    Android -> Android : locationTrackingEnabled = true
    Android -->> Traveler
  else if user refuses
    Traveler --> Android: selectDecline()
    Android -> Android : locationTrackingEnabled = false
    Android -->> Traveler
  end
end

loop while frontend is running
  opt when database hook updates with info
    Webhook ->> Android : trigger listener
    Android -> Android : needsSensorsUpdated = true
  end

  opt if user wants to drag map
    Traveler -> Android : dragMap()
    Android -> Android : needsSensorsUpdated = true
    Android -->> Traveler : updated map
  end

  opt needsSensorsUpdated is true
    Android -> SensorController : getSensorsWithData(boundingBox, preferences)
    note right: boundingBox = the view range\nof what can be seen on the map

    SensorController -> SensorService : getSensorsWithData(boundingBox, preferences)

    SensorService -> SensorProvider : findRelevantSensors(boundingBox, preferences)
    SensorProvider -> Sensors : findIntersectingSensors(boundingBox)
    Sensors -->> SensorProvider : sensors
    SensorProvider -->> SensorService : sensors

    SensorService -> CapturedPollutantProvider : findLatestDataFor(sensors)
    loop sensor ∈ sensors
      CapturedPollutantProvider -> CapturedPollutants : findLatestDataFor(sensor)
      CapturedPollutants -->> CapturedPollutantProvider : sensorData
    end
    CapturedPollutantProvider -->> SensorService : sensorsData

    SensorService -->> SensorController : sensors, sensorsData
    SensorController -->> Android : sensors, sensorsData
  end

  opt when location of user updates
    Android -> SensorController : isUserNearHazardousArea(latitude, longitude)
    SensorController -> SensorService : isUserNearHazardousArea(geoLocation)
    SensorService -> WaypointValidator : isValidWaypoint(geoLocation)

    alt if user location <500m of red zone
      WaypointValidator -->> SensorService : false
      SensorService -->> SensorController : true
      SensorController -->> Android : true

      Android ->> Traveler: alertRedZoneApproach
    else if user is safe
      WaypointValidator -->> SensorService : true
      SensorService -->> SensorController : false
      SensorController -->> Android : false
    end
end

@enduml