packages/SystemUI/src/com/android/systemui/statusbar/notification/people/PeopleHubViewController.kt

/*
 * Copyright (C) 2019 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.statusbar.notification.people

import android.view.View
import com.android.systemui.plugins.ActivityStarter
import com.android.systemui.statusbar.notification.stack.NotificationSectionsManager
import javax.inject.Inject
import javax.inject.Singleton

/** Boundary between the View and PeopleHub, as seen by the View. */
interface PeopleHubSectionFooterViewAdapter {
    fun bindView(viewBoundary: PeopleHubSectionFooterViewBoundary)
}

/** Abstract `View` representation of PeopleHub footer in [NotificationSectionsManager]. */
interface PeopleHubSectionFooterViewBoundary {
    /** View used for animating the activity launch caused by clicking a person in the hub. */
    val associatedViewForClickAnimation: View

    /** [DataListener]s for individual people in the hub. */
    val personViewAdapters: Sequence<DataListener<PersonViewModel?>>

    /** Sets the visibility of the Hub in the notification shade. */
    fun setVisible(isVisible: Boolean)
}

/** Creates a [PeopleHubViewModel] given some additional information required from the `View`. */
interface PeopleHubViewModelFactory {

    /**
     * Creates a [PeopleHubViewModel] that, when clicked, starts an activity using an animation
     * involving the given [view].
     */
    fun createWithAssociatedClickView(view: View): PeopleHubViewModel
}

/**
 * Wraps a [PeopleHubSectionFooterViewBoundary] in a [DataListener], and connects it to the data
 * pipeline.
 *
 * @param dataSource PeopleHub data pipeline.
 */
@Singleton
class PeopleHubSectionFooterViewAdapterImpl @Inject constructor(
    private val dataSource: DataSource<@JvmSuppressWildcards PeopleHubViewModelFactory>
) : PeopleHubSectionFooterViewAdapter {

    override fun bindView(viewBoundary: PeopleHubSectionFooterViewBoundary) =
            dataSource.setListener(PeopleHubDataListenerImpl(viewBoundary))
}

private class PeopleHubDataListenerImpl(
    private val viewBoundary: PeopleHubSectionFooterViewBoundary
) : DataListener<PeopleHubViewModelFactory> {

    override fun onDataChanged(data: PeopleHubViewModelFactory) {
        val viewModel = data.createWithAssociatedClickView(
                viewBoundary.associatedViewForClickAnimation
        )
        viewBoundary.setVisible(viewModel.isVisible)
        val padded = viewModel.people + repeated(null)
        for ((personAdapter, personModel) in viewBoundary.personViewAdapters.zip(padded)) {
            personAdapter.onDataChanged(personModel)
        }
    }
}

/**
 * Converts [PeopleHubModel]s into [PeopleHubViewModelFactory]s.
 *
 * This class serves as the glue between the View layer (which depends on
 * [PeopleHubSectionFooterViewBoundary]) and the Data layer (which produces [PeopleHubModel]s).
 */
@Singleton
class PeopleHubViewModelFactoryDataSourceImpl @Inject constructor(
    private val activityStarter: ActivityStarter,
    private val dataSource: DataSource<@JvmSuppressWildcards PeopleHubModel>
) : DataSource<PeopleHubViewModelFactory> {

    override fun setListener(listener: DataListener<PeopleHubViewModelFactory>) =
            dataSource.setListener(PeopleHubModelListenerImpl(activityStarter, listener))
}

private class PeopleHubModelListenerImpl(
    private val activityStarter: ActivityStarter,
    private val dataListener: DataListener<PeopleHubViewModelFactory>
) : DataListener<PeopleHubModel> {

    override fun onDataChanged(data: PeopleHubModel) =
            dataListener.onDataChanged(PeopleHubViewModelFactoryImpl(data, activityStarter))
}

private class PeopleHubViewModelFactoryImpl(
    private val data: PeopleHubModel,
    private val activityStarter: ActivityStarter
) : PeopleHubViewModelFactory {

    override fun createWithAssociatedClickView(view: View): PeopleHubViewModel {
        val personViewModels = data.people.asSequence().map { personModel ->
            val onClick = {
                activityStarter.startPendingIntentDismissingKeyguard(
                        personModel.clickIntent,
                        null,
                        view
                )
            }
            PersonViewModel(personModel.name, personModel.avatar, onClick)
        }
        return PeopleHubViewModel(personViewModels, data.people.isNotEmpty())
    }
}

private fun <T> repeated(value: T): Sequence<T> = sequence {
    while (true) {
        yield(value)
    }
}