Demonstrating my approach to analytics tracking.

AnalyticsEvent.kt

/**
 * Interface defining the contract of any event that can be tracked in the app. It includes a unique key identifying the event,
 * and ability to record properties.
 */
interface AnalyticsEvent {
  val eventName: String
  val properties: Map<String, Any>
}

AnalyticsTracker.kt

/**
 * Defines the contract of the behavior of any system that tracks events within our application. 
 */
interface AnalyticsTracker {
  fun trackEvent(event: AnalyticsEvent)
}

Events.kt

/**
 * Some events can be expressed as Kotlin objects, because there's nothing dynamic about them. This is usually used for
 * page views.
 */
object ViewedProfileScreenEvent : AnalyticsEvent {
  override val eventName: String = "viewed_profile"
  
  override val properties: Map<String, Any> = emptyMap()
}

/**
 * Some events can be expressed as data classes, because they can have dynamic properties like the source of the page 
 * the user clicked on a button.
 */
data class ClickedAccountButtonEvent(
  private val source: String,
) : AnalyticsEvent {
  override val eventName: String = "clicked_account_button"
  
  override val properties: Map<String, Any> = mapOf(
        "source" to source,
  )

SegmentAnalyticsTracker.kt

/**
 * The concrete implementation takes the other details & maps them to the relevant setup for whatever analytics tool
 * our app uses. 
 */
class SegmentAnalyticsTracker(
    private val segmentInstance: Analytics,
) : AnalyticsTracker {

    override fun trackEvent(analyticsEvent: AnalyticsEvent) {
        val segmentProperties = Properties()
        
        analyticsEvent.properties.forEach { (key, property) ->
            segmentProperties[key] = property
        }

        segmentInstance.track(analyticsEvent.eventName, segmentProperties)
    }
}