/*
 * Copyright (C) 2024 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.communal

import android.annotation.SuppressLint
import android.app.DreamManager
import com.android.systemui.CoreStartable
import com.android.systemui.Flags.communalHub
import com.android.systemui.Flags.glanceableHubAllowKeyguardWhenDreaming
import com.android.systemui.Flags.restartDreamOnUnocclude
import com.android.systemui.dagger.SysUISingleton
import com.android.systemui.dagger.qualifiers.Background
import com.android.systemui.keyguard.domain.interactor.KeyguardInteractor
import com.android.systemui.keyguard.domain.interactor.KeyguardTransitionInteractor
import com.android.systemui.keyguard.shared.model.Edge
import com.android.systemui.keyguard.shared.model.KeyguardState
import com.android.systemui.keyguard.shared.model.TransitionState
import com.android.systemui.keyguard.shared.model.filterState
import com.android.systemui.power.domain.interactor.PowerInteractor
import com.android.systemui.scene.shared.model.Scenes
import com.android.systemui.util.kotlin.Utils.Companion.sampleFilter
import javax.inject.Inject
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.flow.filter
import kotlinx.coroutines.flow.launchIn
import kotlinx.coroutines.flow.onEach

/**
 * A [CoreStartable] responsible for automatically starting the dream when the communal hub is
 * shown, to support the user swiping away the hub to enter the dream.
 */
@SysUISingleton
class CommunalDreamStartable
@Inject
constructor(
    private val powerInteractor: PowerInteractor,
    private val keyguardInteractor: KeyguardInteractor,
    private val keyguardTransitionInteractor: KeyguardTransitionInteractor,
    private val dreamManager: DreamManager,
    @Background private val bgScope: CoroutineScope,
) : CoreStartable {
    @SuppressLint("MissingPermission")
    override fun start() {
        if (!communalHub()) {
            return
        }

        // Return to dream from occluded when not already dreaming.
        if (restartDreamOnUnocclude()) {
            keyguardTransitionInteractor
                .transition(Edge.create(from = KeyguardState.OCCLUDED, to = KeyguardState.DREAMING))
                .filterState(TransitionState.STARTED)
                .sampleFilter(keyguardInteractor.isDreaming) { isDreaming -> !isDreaming }
                .onEach { dreamManager.startDream() }
                .launchIn(bgScope)
        }

        // Restart the dream underneath the hub in order to support the ability to swipe
        // away the hub to enter the dream.
        keyguardTransitionInteractor
            .transition(
                edge = Edge.create(to = Scenes.Communal),
                edgeWithoutSceneContainer = Edge.create(to = KeyguardState.GLANCEABLE_HUB)
            )
            .filterState(TransitionState.FINISHED)
            .sampleFilter(powerInteractor.isAwake) { isAwake ->
                dreamManager.canStartDreaming(isAwake)
            }
            .sampleFilter(keyguardInteractor.isDreaming) { isDreaming -> !isDreaming }
            .filter { !glanceableHubAllowKeyguardWhenDreaming() }
            .onEach { dreamManager.startDream() }
            .launchIn(bgScope)
    }
}