Add component to map activity lifecycle events to trace creation events

embrace-android-features/src/main/kotlin/io/embrace/android/embracesdk/internal/capture/activity/OpenEventEmitter.kt

@@ -0,0 +1,151 @@
+package io.embrace.android.embracesdk.internal.capture.activity
+
+import android.app.Activity
+import android.app.Application.ActivityLifecycleCallbacks
+import android.os.Build
+import android.os.Bundle
+import io.embrace.android.embracesdk.internal.clock.nanosToMillis
+import io.embrace.android.embracesdk.internal.session.lifecycle.ActivityLifecycleListener
+import io.embrace.android.embracesdk.internal.utils.VersionChecker
+import io.opentelemetry.sdk.common.Clock
+
+/**
+ * Maps [ActivityLifecycleCallbacks] events to [OpenEvents] depending on the current state of the app and capabilities of the OS.
+ *
+ * The purpose of this is to leverage Activity lifecycle events to provide data for the underlying workflow to bring a new Activity on
+ * screen. Due to the varying capabilities of the APIs available on the different versions of Android, the precise triggering events for
+ * the start and intermediate steps may differ.
+ *
+ * See [OpenTraceEmitter] for details.
+ */
+class OpenEventEmitter(
+    private val openEvents: OpenEvents,
+    private val clock: Clock,
+    private val versionChecker: VersionChecker,
+) : ActivityLifecycleListener {
+
+    override fun onActivityPreCreated(activity: Activity, savedInstanceState: Bundle?) {
+        create(activity)
+    }
+
+    override fun onActivityCreated(activity: Activity, bundle: Bundle?) {
+        if (!versionChecker.firePrePostEvents()) {
+            create(activity)
+        }
+    }
+
+    override fun onActivityPostCreated(activity: Activity, savedInstanceState: Bundle?) {
+        createEnd(activity)
+    }
+
+    override fun onActivityPreStarted(activity: Activity) {
+        start(activity)
+    }
+
+    override fun onActivityStarted(activity: Activity) {
+        if (!versionChecker.firePrePostEvents()) {
+            createEnd(activity)
+            start(activity)
+        }
+    }
+
+    override fun onActivityPostStarted(activity: Activity) {
+        startEnd(activity)
+    }
+
+    override fun onActivityPreResumed(activity: Activity) {
+        resume(activity)
+    }
+
+    override fun onActivityResumed(activity: Activity) {
+        if (!versionChecker.firePrePostEvents()) {
+            startEnd(activity)
+            resume(activity)
+        }
+    }
+
+    override fun onActivityPostResumed(activity: Activity) {
+        resumeEnd(activity)
+    }
+
+    override fun onActivityPrePaused(activity: Activity) {
+        resetTrace(activity)
+    }
+
+    override fun onActivityPaused(activity: Activity) {
+        if (!versionChecker.firePrePostEvents()) {
+            resetTrace(activity)
+        }
+    }
+
+    override fun onActivityStopped(activity: Activity) {
+        hibernate(activity)
+    }
+
+    private fun resetTrace(activity: Activity) {
+        openEvents.resetTrace(
+            instanceId = traceInstanceId(activity),
+            activityName = activity.localClassName,
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun hibernate(activity: Activity) {
+        openEvents.hibernate(
+            instanceId = traceInstanceId(activity),
+            activityName = activity.localClassName,
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun create(activity: Activity) {
+        openEvents.create(
+            instanceId = traceInstanceId(activity),
+            activityName = activity.localClassName,
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun createEnd(activity: Activity) {
+        openEvents.createEnd(
+            instanceId = traceInstanceId(activity),
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun start(activity: Activity) {
+        openEvents.start(
+            instanceId = traceInstanceId(activity),
+            activityName = activity.localClassName,
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun startEnd(activity: Activity) {
+        openEvents.startEnd(
+            instanceId = traceInstanceId(activity),
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun resume(activity: Activity) {
+        openEvents.resume(
+            instanceId = traceInstanceId(activity),
+            activityName = activity.localClassName,
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun resumeEnd(activity: Activity) {
+        openEvents.resumeEnd(
+            instanceId = traceInstanceId(activity),
+            timestampMs = nowMs()
+        )
+    }
+
+    private fun VersionChecker.firePrePostEvents(): Boolean = isAtLeast(Build.VERSION_CODES.Q)
+
+    private fun traceInstanceId(activity: Activity): Int = activity.hashCode()
+
+    private fun nowMs(): Long = clock.now().nanosToMillis()
+}