/*
 * 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.glanceableHubAllowKeyguardWhenDreaming
import com.android.systemui.Flags.restartDreamOnUnocclude
import com.android.systemui.communal.domain.interactor.CommunalSceneInteractor
import com.android.systemui.communal.domain.interactor.CommunalSettingsInteractor
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.flag.SceneContainerFlag
import com.android.systemui.scene.shared.model.Scenes
import com.android.systemui.util.kotlin.BooleanFlowOperators.allOf
import com.android.systemui.util.kotlin.BooleanFlowOperators.not
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.map
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 communalSettingsInteractor: CommunalSettingsInteractor,
    private val keyguardInteractor: KeyguardInteractor,
    private val keyguardTransitionInteractor: KeyguardTransitionInteractor,
    private val dreamManager: DreamManager,
    private val communalSceneInteractor: CommunalSceneInteractor,
    @Background private val bgScope: CoroutineScope,
) : CoreStartable {
    /** Flow that emits when the dream should be started underneath the glanceable hub. */
    val startDream =
        allOf(
                keyguardTransitionInteractor
                    .transitionValue(Scenes.Communal, KeyguardState.GLANCEABLE_HUB)
                    .map { it == 1f },
                // Use isDreamingAny because isDreaming is false in doze and doesn't change again
                // when the screen turns on, which causes the dream to not start underneath the hub.
                not(keyguardInteractor.isDreamingAny),
                // TODO(b/362830856): Remove this workaround.
                keyguardInteractor.isKeyguardShowing,
                not(communalSceneInteractor.isLaunchingWidget),
                not(keyguardInteractor.isKeyguardOccluded),
            )
            .filter { it }

    @SuppressLint("MissingPermission")
    override fun start() {
        if (!communalSettingsInteractor.isCommunalFlagEnabled() || SceneContainerFlag.isEnabled) {
            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)
        }

        // With hub v2, we no longer need to keep the dream running underneath the hub as there is
        // no more swipe between the hub and dream. We can just start the dream on-demand when the
        // user presses the dream coin.
        if (!communalSettingsInteractor.isV2FlagEnabled()) {
            // Restart the dream underneath the hub in order to support the ability to swipe away
            // the hub to enter the dream.
            startDream
                .sampleFilter(powerInteractor.isAwake) { isAwake ->
                    !glanceableHubAllowKeyguardWhenDreaming() &&
                        dreamManager.canStartDreaming(isAwake)
                }
                .onEach { dreamManager.startDream() }
                .launchIn(bgScope)
        }
    }
}