Analytics Events & Funnels

Copy codearticle_view
article_read_complete
search_query_submitted
cart_item_added
checkout_started
checkout_completed
payment_failed

Copy codesealed class AnalyticsEvent {
    abstract val name: String
    abstract val params: Map<String, Any>

    data class ArticleViewed(
        val articleId: String,
        val title: String,
        val source: String,      // "feed", "search", "deeplink"
        val readingTime: Int     // estimated reading time in seconds
    ) : AnalyticsEvent() {
        override val name = "article_view"
        override val params = mapOf(
            "article_id" to articleId,
            "article_title" to title,
            "source" to source,
            "estimated_reading_time" to readingTime
        )
    }

    data class SearchPerformed(
        val query: String,
        val resultCount: Int,
        val hasFilters: Boolean
    ) : AnalyticsEvent() {
        override val name = "search_query_submitted"
        override val params = mapOf(
            "query_length" to query.length,
            "result_count" to resultCount,
            "has_filters" to hasFilters
        )
    }
}

Copy codeinterface AnalyticsTracker {
    fun track(event: AnalyticsEvent)
    fun setUserProperty(name: String, value: String)
    fun setUserId(id: String)
}

class FirebaseAnalyticsTracker(
    private val analytics: FirebaseAnalytics
) : AnalyticsTracker {

    override fun track(event: AnalyticsEvent) {
        analytics.logEvent(event.name) {
            event.params.forEach { (key, value) ->
                when (value) {
                    is String -> param(key, value)
                    is Long -> param(key, value)
                    is Double -> param(key, value)
                    is Int -> param(key, value.toLong())
                    is Boolean -> param(key, if (value) 1L else 0L)
                }
            }
        }
    }

    override fun setUserProperty(name: String, value: String) {
        analytics.setUserProperty(name, value)
    }

    override fun setUserId(id: String) {
        analytics.setUserId(id)
    }
}

// Debug/test implementation
class LoggingAnalyticsTracker : AnalyticsTracker {
    override fun track(event: AnalyticsEvent) {
        Log.d("Analytics", "[${event.name}] ${event.params}")
    }
    override fun setUserProperty(name: String, value: String) {}
    override fun setUserId(id: String) {}
}

Copy code@HiltViewModel
class ArticleViewModel @Inject constructor(
    private val repository: ArticleRepository,
    private val analytics: AnalyticsTracker
) : ViewModel() {

    fun onArticleOpened(articleId: String) = viewModelScope.launch {
        val article = repository.getArticle(articleId)
        analytics.track(AnalyticsEvent.ArticleViewed(
            articleId = article.id,
            title = article.title,
            source = "feed",
            readingTime = article.estimatedReadingTime
        ))
    }
}

Copy codeCheckout Funnel:
1. cart_view              (users who saw the cart)
2. checkout_started       (tapped "Checkout")
3. payment_info_entered   (filled payment form)
4. checkout_completed     (order placed)

Drop-off rate:
cart_view → checkout_started: 40% conversion (60% abandon)
checkout_started → payment_entered: 80%
payment_entered → completed: 85%

Product decision: fix the 60% cart-to-checkout drop-off

Copy code// Instrument each funnel step
fun onCartViewed() = analytics.track(AnalyticsEvent.CartViewed(itemCount = items.size))
fun onCheckoutTapped() = analytics.track(AnalyticsEvent.CheckoutStarted(cartValue = cart.total))
fun onPaymentEntered() = analytics.track(AnalyticsEvent.PaymentInfoEntered)
fun onOrderPlaced(orderId: String) = analytics.track(AnalyticsEvent.CheckoutCompleted(orderId))

Copy code// Set once at login; used to segment all events
analytics.setUserId(user.id)
analytics.setUserProperty("subscription_tier", user.tier.name)  // FREE, PRO, ENTERPRISE
analytics.setUserProperty("days_since_signup", user.daysSinceSignup.toString())
analytics.setUserProperty("content_language", user.preferredLanguage)