1 /*
2  * Copyright (C) 2023 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.systemui.keyguard.ui.viewmodel
18 
19 import android.util.MathUtils
20 import com.android.systemui.dagger.SysUISingleton
21 import com.android.systemui.keyguard.domain.interactor.FromAodTransitionInteractor
22 import com.android.systemui.keyguard.shared.model.Edge
23 import com.android.systemui.keyguard.shared.model.KeyguardState.AOD
24 import com.android.systemui.keyguard.shared.model.KeyguardState.OCCLUDED
25 import com.android.systemui.keyguard.ui.KeyguardTransitionAnimationFlow
26 import com.android.systemui.keyguard.ui.transitions.DeviceEntryIconTransition
27 import javax.inject.Inject
28 import kotlin.time.Duration.Companion.milliseconds
29 import kotlinx.coroutines.flow.Flow
30 
31 /** Breaks down AOD->OCCLUDED transition into discrete steps for corresponding views to consume. */
32 @SysUISingleton
33 class AodToOccludedTransitionViewModel
34 @Inject
35 constructor(
36     animationFlow: KeyguardTransitionAnimationFlow,
37 ) : DeviceEntryIconTransition {
38     private val transitionAnimation =
39         animationFlow.setup(
40             duration = FromAodTransitionInteractor.TO_OCCLUDED_DURATION,
41             edge = Edge.create(from = AOD, to = OCCLUDED),
42         )
43 
44     /**
45      * Fade out the lockscreen during a transition to OCCLUDED.
46      *
47      * This happens when pressing the power button while a SHOW_WHEN_LOCKED activity is on the top
48      * of the task stack, as well as when the power button is double tapped on the LOCKSCREEN (the
49      * first tap transitions to AOD, the second cancels that transition and starts AOD -> OCCLUDED.
50      */
lockscreenAlphanull51     fun lockscreenAlpha(viewState: ViewStateAccessor): Flow<Float> {
52         var currentAlpha = 0f
53         return transitionAnimation.sharedFlow(
54             duration = 250.milliseconds,
55             startTime = 100.milliseconds, // Wait for the light reveal to "hit" the LS elements.
56             onStart = { currentAlpha = viewState.alpha() },
57             onStep = { MathUtils.lerp(currentAlpha, 0f, it) },
58             onCancel = { 0f },
59         )
60     }
61 
62     override val deviceEntryParentViewAlpha = transitionAnimation.immediatelyTransitionTo(0f)
63 }
64