Notification Minimalism Prototype

When the flag is enabled:
* Cap notifications on lock screen at 1, excluding the UMO
* Act as if LOCK_SCREEN_SHOW_ONLY_UNSEEN_NOTIFICATIONS is Enabled

Bug: 330387368
Test: atest SystemUITests
Flag: ACONFIG com.android.systemui.notification_minimalism_prototype DEVELOPMENT
Change-Id: Ibc47fd1858b62abcab557198ebaf5f2f4587bf11
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 8da5021..21af1a2 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -25,6 +25,16 @@
 }
 
 flag {
+   name: "notification_minimalism_prototype"
+   namespace: "systemui"
+   description: "Prototype of notification minimalism; the new 'Intermediate' lockscreen customization proposal."
+   bug: "330387368"
+   metadata {
+        purpose: PURPOSE_BUGFIX
+   }
+}
+
+flag {
    name: "notification_view_flipper_pausing"
    namespace: "systemui"
    description: "Pause ViewFlippers inside Notification custom layouts when the shade is closed."
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/collection/coordinator/KeyguardCoordinator.kt b/packages/SystemUI/src/com/android/systemui/statusbar/notification/collection/coordinator/KeyguardCoordinator.kt
index 0c69a65..8531eaa 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/collection/coordinator/KeyguardCoordinator.kt
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/collection/coordinator/KeyguardCoordinator.kt
@@ -22,6 +22,7 @@
 import android.provider.Settings
 import androidx.annotation.VisibleForTesting
 import com.android.systemui.Dumpable
+import com.android.systemui.Flags.notificationMinimalismPrototype
 import com.android.systemui.dagger.qualifiers.Application
 import com.android.systemui.dagger.qualifiers.Background
 import com.android.systemui.dump.DumpManager
@@ -59,6 +60,7 @@
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.conflate
 import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
@@ -260,8 +262,11 @@
         }
     }
 
-    private suspend fun trackUnseenFilterSettingChanges() {
-        secureSettings
+    private fun unseenFeatureEnabled(): Flow<Boolean> {
+        if (notificationMinimalismPrototype()) {
+            return flowOf(true)
+        }
+        return secureSettings
             // emit whenever the setting has changed
             .observerFlow(
                 UserHandle.USER_ALL,
@@ -283,17 +288,20 @@
             // only track the most recent emission, if events are happening faster than they can be
             // consumed
             .conflate()
-            .collectLatest { setting ->
-                // update local field and invalidate if necessary
-                if (setting != unseenFilterEnabled) {
-                    unseenFilterEnabled = setting
-                    unseenNotifFilter.invalidateList("unseen setting changed")
-                }
-                // if the setting is enabled, then start tracking and filtering unseen notifications
-                if (setting) {
-                    trackSeenNotifications()
-                }
+    }
+
+    private suspend fun trackUnseenFilterSettingChanges() {
+        unseenFeatureEnabled().collectLatest { setting ->
+            // update local field and invalidate if necessary
+            if (setting != unseenFilterEnabled) {
+                unseenFilterEnabled = setting
+                unseenNotifFilter.invalidateList("unseen setting changed")
             }
+            // if the setting is enabled, then start tracking and filtering unseen notifications
+            if (setting) {
+                trackSeenNotifications()
+            }
+        }
     }
 
     private val collectionListener =
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackSizeCalculator.kt b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackSizeCalculator.kt
index 2d9c63e..1b53cbe 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackSizeCalculator.kt
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackSizeCalculator.kt
@@ -20,6 +20,7 @@
 import android.util.Log
 import android.view.View.GONE
 import androidx.annotation.VisibleForTesting
+import com.android.systemui.Flags.notificationMinimalismPrototype
 import com.android.systemui.res.R
 import com.android.systemui.dagger.SysUISingleton
 import com.android.systemui.dagger.qualifiers.Main
@@ -66,6 +67,11 @@
      */
     private var maxKeyguardNotifications by notNull<Int>()
 
+    /**
+     * Whether [maxKeyguardNotifications] will have 1 added to it when media is shown in the stack.
+     */
+    private var maxNotificationsExcludesMedia = false
+
     /** Minimum space between two notifications, see [calculateGapAndDividerHeight]. */
     private var dividerHeight by notNull<Float>()
 
@@ -168,7 +174,11 @@
         log { "\n" }
 
         val stackHeightSequence = computeHeightPerNotificationLimit(stack, shelfHeight)
+
+        // TODO: Avoid making this split shade assumption by simply checking the stack for media
         val isMediaShowing = mediaDataManager.hasActiveMediaOrRecommendation()
+        val isMediaShowingInStack = isMediaShowing && !splitShadeStateController
+                .shouldUseSplitNotificationShade(resources)
 
         log { "\tGet maxNotifWithoutSavingSpace ---" }
         val maxNotifWithoutSavingSpace =
@@ -181,12 +191,11 @@
             }
 
         // How many notifications we can show at heightWithoutLockscreenConstraints
-        var minCountAtHeightWithoutConstraints =
-            if (isMediaShowing && !splitShadeStateController
-                    .shouldUseSplitNotificationShade(resources)) 2 else 1
+        val minCountAtHeightWithoutConstraints = if (isMediaShowingInStack) 2 else 1
         log {
             "\t---maxNotifWithoutSavingSpace=$maxNotifWithoutSavingSpace " +
                 "isMediaShowing=$isMediaShowing" +
+                "isMediaShowingInStack=$isMediaShowingInStack" +
                 "minCountAtHeightWithoutConstraints=$minCountAtHeightWithoutConstraints"
         }
         log { "\n" }
@@ -223,7 +232,9 @@
         }
 
         if (onLockscreen()) {
-            maxNotifications = min(maxKeyguardNotifications, maxNotifications)
+            val increaseMaxForMedia = maxNotificationsExcludesMedia && isMediaShowingInStack
+            val lockscreenMax = maxKeyguardNotifications.safeIncrementIf(increaseMaxForMedia)
+            maxNotifications = min(lockscreenMax, maxNotifications)
         }
 
         // Could be < 0 if the space available is less than the shelf size. Returns 0 in this case.
@@ -276,7 +287,7 @@
             height = notifsHeight + shelfHeightWithSpaceBefore
             log {
                 "--- computeHeight(maxNotifs=$maxNotifs, shelfHeight=$shelfHeight)" +
-                    " -> ${height}=($notifsHeight+$shelfHeightWithSpaceBefore)" +
+                    " -> $height=($notifsHeight+$shelfHeightWithSpaceBefore)" +
                     " | saveSpaceOnLockscreen=$saveSpaceOnLockscreen"
             }
         }
@@ -367,8 +378,9 @@
     }
 
     fun updateResources() {
-        maxKeyguardNotifications =
-            infiniteIfNegative(resources.getInteger(R.integer.keyguard_max_notification_count))
+        maxKeyguardNotifications = if (notificationMinimalismPrototype()) 1
+            else infiniteIfNegative(resources.getInteger(R.integer.keyguard_max_notification_count))
+        maxNotificationsExcludesMedia = notificationMinimalismPrototype()
 
         dividerHeight =
             max(1f, resources.getDimensionPixelSize(R.dimen.notification_divider_height).toFloat())
@@ -486,6 +498,13 @@
             v
         }
 
+    private fun Int.safeIncrementIf(condition: Boolean): Int =
+        if (condition && this != Int.MAX_VALUE) {
+            this + 1
+        } else {
+            this
+        }
+
     /** Returns the last index where [predicate] returns true, or -1 if it was always false. */
     private fun <T> Sequence<T>.lastIndexWhile(predicate: (T) -> Boolean): Int =
         takeWhile(predicate).count() - 1