Add privileged alert policy endpoint

app/src/main/AndroidManifest.xml

@@ -37,6 +37,10 @@
                 <action android:name="android.service.notification.NotificationListenerService" />
             </intent-filter>
         </service>
+
+        <service
+            android:name=".module.AlertPolicyService"
+            android:exported="true" />
     </application>
 
 </manifest>

app/src/main/java/se/ajpanton/notificationsmaster/alerts/AlertNotificationDispatcher.kt

@@ -11,21 +11,7 @@ object AlertNotificationDispatcher {
         event: AlertEvent,
         isRoutineUpdate: Boolean,
     ): List<QueuedAlert> {
-        if (!configuration.enabled ||
-            event.source == AlertSource.NOTIFICATION_UPDATE &&
-            isRoutineUpdate &&
-            configuration.ignoreRoutineUpdates
-        ) {
-            return emptyList()
-        }
-        val app = configuration.appSettings.firstOrNull { it.packageName == event.packageName }
-            ?: AlertAppSettings(event.packageName)
-        return AlertRuleEvaluator.evaluate(
-            app,
-            configuration.rules,
-            configuration.profiles.associateBy { it.id },
-            event,
-        ).decisions.mapNotNull { decision ->
+        return AlertPolicyEvaluator.evaluate(configuration, event, isRoutineUpdate).decisions.mapNotNull { decision ->
             decision.snapshot()?.let { QueuedAlert(decision.ruleId, it) }
         }
     }

app/src/main/java/se/ajpanton/notificationsmaster/alerts/AlertPolicyEvaluator.kt

@@ -0,0 +1,21 @@
+package se.ajpanton.notificationsmaster.alerts
+
+/** Evaluates saved alert policy without deciding how a caller will play it. */
+object AlertPolicyEvaluator {
+    fun evaluate(
+        configuration: AlertConfiguration,
+        event: AlertEvent,
+        isRoutineUpdate: Boolean,
+    ): AlertEvaluation {
+        if (!configuration.enabled ||
+            event.source == AlertSource.NOTIFICATION_UPDATE &&
+            isRoutineUpdate &&
+            configuration.ignoreRoutineUpdates
+        ) {
+            return AlertEvaluation(emptyList(), false)
+        }
+        val app = configuration.appSettings.firstOrNull { it.packageName == event.packageName }
+            ?: AlertAppSettings(event.packageName)
+        return AlertRuleEvaluator.evaluate(app, configuration.rules, configuration.profiles.associateBy { it.id }, event)
+    }
+}

app/src/main/java/se/ajpanton/notificationsmaster/module/AlertPolicyService.kt

@@ -0,0 +1,64 @@
+package se.ajpanton.notificationsmaster.module
+
+import android.app.Service
+import android.content.Intent
+import android.os.Binder
+import android.os.IBinder
+import android.os.Parcel
+import se.ajpanton.notificationsmaster.alerts.AlertConfigurationStore
+import se.ajpanton.notificationsmaster.alerts.AlertEvent
+import se.ajpanton.notificationsmaster.alerts.AlertPolicyEvaluator
+import se.ajpanton.notificationsmaster.alerts.AlertSource
+import se.ajpanton.notificationsmaster.alerts.snapshot
+
+/**
+ * A deliberately narrow endpoint for the optional system-server module.
+ * It is exported only so system_server can bind. A bind itself is not a
+ * sensitive operation; every transaction is authenticated before encrypted
+ * app data is read.
+ */
+class AlertPolicyService : Service() {
+    override fun onBind(intent: Intent): IBinder = PolicyBinder(applicationContext)
+
+    private class PolicyBinder(context: android.content.Context) : Binder() {
+        private val configurationStore = AlertConfigurationStore(context)
+
+        init { attachInterface(null, DESCRIPTOR) }
+
+        override fun onTransact(code: Int, data: Parcel, reply: Parcel?, flags: Int): Boolean {
+            if (Binder.getCallingUid() != android.os.Process.SYSTEM_UID) return false
+            if (code == INTERFACE_TRANSACTION) {
+                reply?.writeString(DESCRIPTOR)
+                return true
+            }
+            if (code != TRANSACTION_EVALUATE || reply == null) return false
+            data.enforceInterface(DESCRIPTOR)
+            val packageName = data.readString() ?: return false
+            val source = runCatching { AlertSource.valueOf(data.readString() ?: return false) }.getOrNull() ?: return false
+            val event = AlertEvent(packageName, source, data.readString(), data.readString(), data.readString())
+            val routineUpdate = data.readBoolean()
+            val result = AlertPolicyEvaluator.evaluate(configurationStore.load(), event, routineUpdate)
+            reply.writeNoException()
+            reply.writeBoolean(result.silenceUnmatchedDirectAlert)
+            reply.writeInt(result.decisions.size)
+            result.decisions.forEach { decision ->
+                reply.writeString(decision.ruleId)
+                reply.writeString(decision.outcome.name)
+                val snapshot = decision.snapshot()
+                reply.writeBoolean(snapshot != null)
+                snapshot?.let {
+                    reply.writeString(it.soundUri)
+                    reply.writeLongArray(it.vibrationPattern.toLongArray())
+                    reply.writeBoolean(it.playToCompletion)
+                    reply.writeBoolean(it.allowDuringDnd)
+                }
+            }
+            return true
+        }
+    }
+
+    companion object {
+        const val DESCRIPTOR = "se.ajpanton.notificationsmaster.AlertPolicy"
+        const val TRANSACTION_EVALUATE = IBinder.FIRST_CALL_TRANSACTION
+    }
+}

app/src/test/java/se/ajpanton/notificationsmaster/alerts/AlertPolicyEvaluatorTest.kt

@@ -0,0 +1,20 @@
+package se.ajpanton.notificationsmaster.alerts
+
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+
+class AlertPolicyEvaluatorTest {
+    private val profile = AlertProfile("profile", "Profile", vibrationPattern = listOf(0, 10))
+    private val rule = AlertRule("rule", "chat.app", 0, setOf(AlertSource.NOTIFICATION_POST), outcome = AlertOutcome.PLAY_PROFILE, profileId = profile.id)
+
+    @Test fun `returns no decision when alerting is disabled`() {
+        assertTrue(AlertPolicyEvaluator.evaluate(AlertConfiguration(enabled = false, profiles = listOf(profile), rules = listOf(rule)), event(), false).decisions.isEmpty())
+    }
+
+    @Test fun `returns the evaluated decision for a post`() {
+        assertEquals(listOf("rule"), AlertPolicyEvaluator.evaluate(AlertConfiguration(profiles = listOf(profile), rules = listOf(rule)), event(), false).decisions.map { it.ruleId })
+    }
+
+    private fun event() = AlertEvent("chat.app", AlertSource.NOTIFICATION_POST)
+}