Auxio/app/src/main/java/org/oxycblt/auxio/AuxioService.kt

/*
 * Copyright (c) 2024 Auxio Project
 * AuxioService.kt is part of Auxio.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
package org.oxycblt.auxio

import android.annotation.SuppressLint
import android.content.Context
import android.content.Intent
import android.os.Bundle
import android.os.IBinder
import android.support.v4.media.MediaBrowserCompat.MediaItem
import androidx.annotation.StringRes
import androidx.core.app.NotificationChannelCompat
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import androidx.core.app.ServiceCompat
import androidx.media.MediaBrowserServiceCompat
import androidx.media.utils.MediaConstants
import dagger.hilt.android.AndroidEntryPoint
import javax.inject.Inject
import org.oxycblt.auxio.music.service.MusicServiceFragment
import org.oxycblt.auxio.playback.service.PlaybackServiceFragment

@AndroidEntryPoint
class AuxioService :
    MediaBrowserServiceCompat(), ForegroundListener, MusicServiceFragment.Invalidator {
    @Inject lateinit var playbackFragmentFactory: PlaybackServiceFragment.Factory
    private lateinit var playbackFragment: PlaybackServiceFragment

    @Inject lateinit var musicFragmentFactory: MusicServiceFragment.Factory
    private lateinit var musicFragment: MusicServiceFragment

    @SuppressLint("WrongConstant")
    override fun onCreate() {
        super.onCreate()
        playbackFragment = playbackFragmentFactory.create(this, this)
        sessionToken = playbackFragment.attach()
        musicFragment = musicFragmentFactory.create(this, this, this)
        musicFragment.attach()
    }

    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
        // TODO: Start command occurring from a foreign service basically implies a detached
        //  service, we might need more handling here.
        onHandleForeground(intent)
        return super.onStartCommand(intent, flags, startId)
    }

    override fun onBind(intent: Intent): IBinder? {
        onHandleForeground(intent)
        return super.onBind(intent)
    }

    private fun onHandleForeground(intent: Intent?) {
        val startId = intent?.getIntExtra(INTENT_KEY_START_ID, -1) ?: -1
        musicFragment.start()
        playbackFragment.start(startId)
    }

    override fun onTaskRemoved(rootIntent: Intent?) {
        super.onTaskRemoved(rootIntent)
        playbackFragment.handleTaskRemoved()
    }

    override fun onDestroy() {
        super.onDestroy()
        musicFragment.release()
        playbackFragment.release()
        sessionToken = null
    }

    override fun onGetRoot(
        clientPackageName: String,
        clientUid: Int,
        rootHints: Bundle?
    ): BrowserRoot {
        val maximumRootChildLimit =
            rootHints?.getInt(MediaConstants.BROWSER_ROOT_HINTS_KEY_ROOT_CHILDREN_LIMIT, 4) ?: 4
        return musicFragment.getRoot(maximumRootChildLimit)
    }

    override fun onLoadItem(itemId: String, result: Result<MediaItem>) {
        musicFragment.getItem(itemId, result)
    }

    override fun onLoadChildren(parentId: String, result: Result<MutableList<MediaItem>>) {
        musicFragment.getChildren(parentId, result)
    }

    override fun onSearch(query: String, extras: Bundle?, result: Result<MutableList<MediaItem>>) {
        musicFragment.search(query, result)
    }

    override fun updateForeground(change: ForegroundListener.Change) {
        val mediaNotification = playbackFragment.notification
        if (mediaNotification != null) {
            if (change == ForegroundListener.Change.MEDIA_SESSION) {
                startForeground(mediaNotification.code, mediaNotification.build())
            }
            // Nothing changed, but don't show anything music related since we can always
            // index during playback.
        } else {
            musicFragment.createNotification {
                if (it != null) {
                    startForeground(it.code, it.build())
                    isForeground = true
                } else {
                    ServiceCompat.stopForeground(this, ServiceCompat.STOP_FOREGROUND_REMOVE)
                    isForeground = false
                }
            }
        }
    }

    override fun invalidateMusic(mediaId: String) {
        notifyChildrenChanged(mediaId)
    }

    companion object {
        var isForeground = false
            private set

        // This is only meant for Auxio to internally ensure that it's state management will work.
        const val INTENT_KEY_START_ID = BuildConfig.APPLICATION_ID + ".service.START_ID"
    }
}

interface ForegroundListener {
    fun updateForeground(change: Change)

    enum class Change {
        MEDIA_SESSION,
        INDEXER
    }
}

/**
 * Wrapper around [NotificationCompat.Builder] intended for use for [NotificationCompat]s that
 * signal a Service's ongoing foreground state.
 *
 * @author Alexander Capehart (OxygenCobalt)
 */
abstract class ForegroundServiceNotification(context: Context, info: ChannelInfo) :
    NotificationCompat.Builder(context, info.id) {
    private val notificationManager = NotificationManagerCompat.from(context)

    init {
        // Set up the notification channel. Foreground notifications are non-substantial, and
        // thus make no sense to have lights, vibration, or lead to a notification badge.
        val channel =
            NotificationChannelCompat.Builder(info.id, NotificationManagerCompat.IMPORTANCE_LOW)
                .setName(context.getString(info.nameRes))
                .setLightsEnabled(false)
                .setVibrationEnabled(false)
                .setShowBadge(false)
                .build()
        notificationManager.createNotificationChannel(channel)
    }

    /**
     * The code used to identify this notification.
     *
     * @see NotificationManagerCompat.notify
     */
    abstract val code: Int

    /**
     * Reduced representation of a [NotificationChannelCompat].
     *
     * @param id The ID of the channel.
     * @param nameRes A string resource ID corresponding to the human-readable name of this channel.
     */
    data class ChannelInfo(val id: String, @StringRes val nameRes: Int)
}