Add basic structure for keyboard backlight indicator functionality

- KeyboardBacklightInteractor produces events whenever keyboard backlight changes
- That is consumed by BacklightDialogViewModel which based on that decides when dialog should be shown or hidden
- That dialog state is consumed by KeyboardBacklightDialogCoordinator which creates and shows dialog or hides it
- BacklightDialogContentViewModel is viewModel for dialog itself

Flag: KEYBOARD_BACKLIGHT_INDICATOR
Fixes: 268645018
Fixes: 268645743
Test: KeyboardBacklightChangeInteractorTest
Test: BacklightDialogViewModelTest
Change-Id: If2029ad8107e018e822237b576578444c34b9212

packages/SystemUI/src/com/android/systemui/keyboard/PhysicalKeyboardCoreStartable.kt

@@ -21,6 +21,7 @@ import com.android.systemui.CoreStartable
 import com.android.systemui.dagger.SysUISingleton
 import com.android.systemui.flags.FeatureFlags
 import com.android.systemui.flags.Flags
+import com.android.systemui.keyboard.backlight.ui.KeyboardBacklightDialogCoordinator
 import javax.inject.Inject
 
 /** A [CoreStartable] that launches components interested in physical keyboard interaction. */
@@ -28,11 +29,12 @@ import javax.inject.Inject
 class PhysicalKeyboardCoreStartable
 @Inject
 constructor(
+    private val keyboardBacklightDialogCoordinator: KeyboardBacklightDialogCoordinator,
     private val featureFlags: FeatureFlags,
 ) : CoreStartable {
     override fun start() {
         if (featureFlags.isEnabled(Flags.KEYBOARD_BACKLIGHT_INDICATOR)) {
-            // TODO(b/268645743) start listening for keyboard backlight brightness
+            keyboardBacklightDialogCoordinator.startListening()
         }
     }
 }

packages/SystemUI/src/com/android/systemui/keyboard/backlight/domain/interactor/KeyboardBacklightInteractor.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.domain.interactor
+
+import com.android.systemui.dagger.SysUISingleton
+import com.android.systemui.keyboard.data.repository.KeyboardRepository
+import com.android.systemui.keyboard.shared.model.BacklightModel
+import javax.inject.Inject
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flowOf
+
+/** Allows listening to changes to keyboard backlight level */
+@SysUISingleton
+class KeyboardBacklightInteractor
+@Inject
+constructor(
+    private val keyboardRepository: KeyboardRepository,
+) {
+
+    /** Emits current backlight level as [BacklightModel] or null if keyboard is not connected */
+    val backlight: Flow<BacklightModel?> =
+        keyboardRepository.keyboardConnected.flatMapLatest { connected ->
+            if (connected) keyboardRepository.backlight else flowOf(null)
+        }
+}

packages/SystemUI/src/com/android/systemui/keyboard/backlight/ui/KeyboardBacklightDialogCoordinator.kt

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.ui
+
+import android.content.Context
+import com.android.systemui.dagger.SysUISingleton
+import com.android.systemui.dagger.qualifiers.Application
+import com.android.systemui.keyboard.backlight.ui.view.KeyboardBacklightDialog
+import com.android.systemui.keyboard.backlight.ui.viewmodel.BacklightDialogViewModel
+import javax.inject.Inject
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.launch
+
+/**
+ * Based on the state produced from [BacklightDialogViewModel] shows or hides keyboard backlight
+ * indicator
+ */
+@SysUISingleton
+class KeyboardBacklightDialogCoordinator
+@Inject
+constructor(
+    @Application private val applicationScope: CoroutineScope,
+    private val context: Context,
+    private val viewModel: BacklightDialogViewModel,
+) {
+
+    var dialog: KeyboardBacklightDialog? = null
+
+    fun startListening() {
+        applicationScope.launch {
+            viewModel.dialogContent.collect { dialogViewModel ->
+                if (dialogViewModel != null) {
+                    if (dialog == null) {
+                        dialog = KeyboardBacklightDialog(context, dialogViewModel)
+                        // pass viewModel and show
+                    }
+                } else {
+                    dialog?.dismiss()
+                    dialog = null
+                }
+            }
+        }
+    }
+}

packages/SystemUI/src/com/android/systemui/keyboard/backlight/ui/view/KeyboardBacklightDialog.kt

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.ui.view
+
+import android.app.Dialog
+import android.content.Context
+import android.os.Bundle
+import com.android.systemui.keyboard.backlight.ui.viewmodel.BacklightDialogContentViewModel
+
+class KeyboardBacklightDialog(context: Context, val viewModel: BacklightDialogContentViewModel) :
+    Dialog(context) {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        // TODO(b/268650355) Implement the dialog
+    }
+}

packages/SystemUI/src/com/android/systemui/keyboard/backlight/ui/viewmodel/BacklightDialogContentViewModel.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.ui.viewmodel
+
+data class BacklightDialogContentViewModel(val currentValue: Int, val maxValue: Int)

packages/SystemUI/src/com/android/systemui/keyboard/backlight/ui/viewmodel/BacklightDialogViewModel.kt

@@ -0,0 +1,72 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.ui.viewmodel
+
+import android.view.accessibility.AccessibilityManager
+import com.android.systemui.dagger.SysUISingleton
+import com.android.systemui.keyboard.backlight.domain.interactor.KeyboardBacklightInteractor
+import com.android.systemui.statusbar.policy.AccessibilityManagerWrapper
+import javax.inject.Inject
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.filterNotNull
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.map
+
+/**
+ * Responsible for dialog visibility and content - emits [BacklightDialogContentViewModel] if dialog
+ * should be shown and hidden otherwise
+ */
+@SysUISingleton
+class BacklightDialogViewModel
+@Inject
+constructor(
+    interactor: KeyboardBacklightInteractor,
+    private val accessibilityManagerWrapper: AccessibilityManagerWrapper,
+) {
+
+    private val timeoutMillis: Long
+        get() =
+            accessibilityManagerWrapper
+                .getRecommendedTimeoutMillis(
+                    DEFAULT_DIALOG_TIMEOUT_MILLIS,
+                    AccessibilityManager.FLAG_CONTENT_ICONS
+                )
+                .toLong()
+
+    val dialogContent: Flow<BacklightDialogContentViewModel?> =
+        interactor.backlight
+            .filterNotNull()
+            .map { BacklightDialogContentViewModel(it.level, it.maxLevel) }
+            .timeout(timeoutMillis, emitAfterTimeout = null)
+
+    private fun <T> Flow<T>.timeout(timeoutMillis: Long, emitAfterTimeout: T): Flow<T> {
+        return flatMapLatest {
+            flow {
+                emit(it)
+                delay(timeoutMillis)
+                emit(emitAfterTimeout)
+            }
+        }
+    }
+
+    private companion object {
+        const val DEFAULT_DIALOG_TIMEOUT_MILLIS = 3000
+    }
+}

packages/SystemUI/src/com/android/systemui/keyboard/data/repository/KeyboardRepository.kt

@@ -23,7 +23,7 @@ import com.android.systemui.common.coroutine.ConflatedCallbackFlow.conflatedCall
 import com.android.systemui.dagger.SysUISingleton
 import com.android.systemui.dagger.qualifiers.Application
 import com.android.systemui.dagger.qualifiers.Background
-import com.android.systemui.keyboard.data.model.BacklightModel
+import com.android.systemui.keyboard.shared.model.BacklightModel
 import javax.inject.Inject
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.CoroutineScope

packages/SystemUI/src/com/android/systemui/keyboard/shared/model/BacklightModel.kt

@@ -15,7 +15,7 @@
  *
  */
 
-package com.android.systemui.keyboard.data.model
+package com.android.systemui.keyboard.shared.model
 
 /**
  * Model for current state of keyboard backlight brightness. [level] indicates current level of

packages/SystemUI/tests/src/com/android/systemui/keyboard/backlight/domain/interactor/KeyboardBacklightInteractorTest.kt

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.domain.interactor
+
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.coroutines.collectLastValue
+import com.android.systemui.keyboard.data.repository.FakeKeyboardRepository
+import com.android.systemui.keyboard.shared.model.BacklightModel
+import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.runTest
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@SmallTest
+@RunWith(JUnit4::class)
+class KeyboardBacklightInteractorTest : SysuiTestCase() {
+
+    private val keyboardRepository = FakeKeyboardRepository()
+    private lateinit var underTest: KeyboardBacklightInteractor
+
+    @Before
+    fun setUp() {
+        underTest = KeyboardBacklightInteractor(keyboardRepository)
+    }
+
+    @Test
+    fun emitsNull_whenKeyboardJustConnected() = runTest {
+        val latest by collectLastValue(underTest.backlight)
+        keyboardRepository.setKeyboardConnected(true)
+
+        assertThat(latest).isNull()
+    }
+
+    @Test
+    fun emitsBacklight_whenKeyboardConnectedAndBacklightChanged() = runTest {
+        keyboardRepository.setKeyboardConnected(true)
+        keyboardRepository.setBacklight(BacklightModel(1, 5))
+
+        assertThat(underTest.backlight.first()).isEqualTo(BacklightModel(1, 5))
+    }
+
+    @Test
+    fun emitsNull_afterKeyboardDisconnecting() = runTest {
+        val latest by collectLastValue(underTest.backlight)
+        keyboardRepository.setKeyboardConnected(true)
+        keyboardRepository.setBacklight(BacklightModel(1, 5))
+
+        keyboardRepository.setKeyboardConnected(false)
+
+        assertThat(latest).isNull()
+    }
+}

packages/SystemUI/tests/src/com/android/systemui/keyboard/backlight/ui/viewmodel/BacklightDialogViewModelTest.kt

@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.backlight.ui.viewmodel
+
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.coroutines.collectLastValue
+import com.android.systemui.keyboard.backlight.domain.interactor.KeyboardBacklightInteractor
+import com.android.systemui.keyboard.data.repository.FakeKeyboardRepository
+import com.android.systemui.keyboard.shared.model.BacklightModel
+import com.android.systemui.statusbar.policy.AccessibilityManagerWrapper
+import com.android.systemui.util.mockito.any
+import com.android.systemui.util.mockito.whenever
+import com.google.common.truth.Truth.assertThat
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.test.advanceTimeBy
+import kotlinx.coroutines.test.runTest
+import org.junit.Before
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+import org.mockito.Mock
+import org.mockito.MockitoAnnotations
+
+@OptIn(ExperimentalCoroutinesApi::class)
+@SmallTest
+@RunWith(JUnit4::class)
+class BacklightDialogViewModelTest : SysuiTestCase() {
+
+    private val keyboardRepository = FakeKeyboardRepository()
+    private lateinit var underTest: BacklightDialogViewModel
+    @Mock private lateinit var accessibilityManagerWrapper: AccessibilityManagerWrapper
+    private val timeoutMillis = 3000L
+
+    @Before
+    fun setUp() {
+        MockitoAnnotations.initMocks(this)
+        whenever(accessibilityManagerWrapper.getRecommendedTimeoutMillis(any(), any()))
+            .thenReturn(timeoutMillis.toInt())
+        underTest =
+            BacklightDialogViewModel(
+                KeyboardBacklightInteractor(keyboardRepository),
+                accessibilityManagerWrapper
+            )
+        keyboardRepository.setKeyboardConnected(true)
+    }
+
+    @Test
+    fun emitsViewModel_whenBacklightChanged() = runTest {
+        keyboardRepository.setBacklight(BacklightModel(1, 5))
+
+        assertThat(underTest.dialogContent.first()).isEqualTo(BacklightDialogContentViewModel(1, 5))
+    }
+
+    @Test
+    fun emitsNull_afterTimeout() = runTest {
+        val latest by collectLastValue(underTest.dialogContent)
+        keyboardRepository.setBacklight(BacklightModel(1, 5))
+
+        assertThat(latest).isEqualTo(BacklightDialogContentViewModel(1, 5))
+        advanceTimeBy(timeoutMillis + 1)
+        assertThat(latest).isNull()
+    }
+
+    @Test
+    fun emitsNull_after5secDelay_fromLastBacklightChange() = runTest {
+        val latest by collectLastValue(underTest.dialogContent)
+        keyboardRepository.setKeyboardConnected(true)
+
+        keyboardRepository.setBacklight(BacklightModel(1, 5))
+        assertThat(latest).isEqualTo(BacklightDialogContentViewModel(1, 5))
+
+        advanceTimeBy(timeoutMillis * 2 / 3)
+        // timeout yet to pass, no new emission
+        keyboardRepository.setBacklight(BacklightModel(2, 5))
+        assertThat(latest).isEqualTo(BacklightDialogContentViewModel(2, 5))
+
+        advanceTimeBy(timeoutMillis * 2 / 3)
+        // timeout refreshed because of last `setBacklight`, still content present
+        assertThat(latest).isEqualTo(BacklightDialogContentViewModel(2, 5))
+
+        advanceTimeBy(timeoutMillis * 2 / 3)
+        // finally timeout reached and null emitted
+        assertThat(latest).isNull()
+    }
+}

packages/SystemUI/tests/utils/src/com/android/systemui/keyboard/data/repository/FakeKeyboardRepository.kt

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package com.android.systemui.keyboard.data.repository
+
+import com.android.systemui.keyboard.shared.model.BacklightModel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.filterNotNull
+
+class FakeKeyboardRepository : KeyboardRepository {
+
+    private val _keyboardConnected = MutableStateFlow(false)
+    override val keyboardConnected: Flow<Boolean> = _keyboardConnected
+
+    private val _backlightState: MutableStateFlow<BacklightModel?> = MutableStateFlow(null)
+    // filtering to make sure backlight doesn't have default initial value
+    override val backlight: Flow<BacklightModel> = _backlightState.filterNotNull()
+
+    fun setBacklight(state: BacklightModel) {
+        _backlightState.value = state
+    }
+
+    fun setKeyboardConnected(connected: Boolean) {
+        _keyboardConnected.value = connected
+    }
+}