/*
 * Copyright (C) 2021 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.permissioncontroller.hibernation

import android.Manifest
import android.Manifest.permission.UPDATE_PACKAGES_WITHOUT_USER_ACTION
import android.accessibilityservice.AccessibilityService
import android.annotation.SuppressLint
import android.app.ActivityManager
import android.app.ActivityManager.RunningAppProcessInfo.IMPORTANCE_CANT_SAVE_STATE
import android.app.AppOpsManager
import android.app.Notification
import android.app.NotificationChannel
import android.app.NotificationManager
import android.app.PendingIntent
import android.app.admin.DeviceAdminReceiver
import android.app.admin.DevicePolicyManager
import android.app.job.JobInfo
import android.app.job.JobParameters
import android.app.job.JobScheduler
import android.app.job.JobService
import android.app.role.RoleManager
import android.app.usage.UsageStats
import android.app.usage.UsageStatsManager.INTERVAL_DAILY
import android.app.usage.UsageStatsManager.INTERVAL_MONTHLY
import android.content.BroadcastReceiver
import android.content.ComponentName
import android.content.Context
import android.content.Intent
import android.content.SharedPreferences
import android.content.pm.PackageManager
import android.content.pm.PackageManager.PERMISSION_GRANTED
import android.os.Bundle
import android.os.Process
import android.os.UserHandle
import android.os.UserManager
import android.printservice.PrintService
import android.provider.DeviceConfig
import android.provider.DeviceConfig.NAMESPACE_APP_HIBERNATION
import android.provider.Settings
import android.service.autofill.AutofillService
import android.service.dreams.DreamService
import android.service.notification.NotificationListenerService
import android.service.voice.VoiceInteractionService
import android.service.wallpaper.WallpaperService
import android.telephony.TelephonyManager.CARRIER_PRIVILEGE_STATUS_HAS_ACCESS
import android.telephony.TelephonyManager.CARRIER_PRIVILEGE_STATUS_NO_ACCESS
import android.util.Log
import android.view.inputmethod.InputMethod
import androidx.annotation.MainThread
import androidx.lifecycle.MutableLiveData
import androidx.preference.PreferenceManager
import com.android.modules.utils.build.SdkLevel
import com.android.permissioncontroller.Constants
import com.android.permissioncontroller.DumpableLog
import com.android.permissioncontroller.PermissionControllerApplication
import com.android.permissioncontroller.R
import com.android.permissioncontroller.hibernation.v31.HibernationController
import com.android.permissioncontroller.hibernation.v31.InstallerPackagesLiveData
import com.android.permissioncontroller.permission.data.AllPackageInfosLiveData
import com.android.permissioncontroller.permission.data.AppOpLiveData
import com.android.permissioncontroller.permission.data.BroadcastReceiverLiveData
import com.android.permissioncontroller.permission.data.CarrierPrivilegedStatusLiveData
import com.android.permissioncontroller.permission.data.DataRepositoryForPackage
import com.android.permissioncontroller.permission.data.HasIntentAction
import com.android.permissioncontroller.permission.data.LauncherPackagesLiveData
import com.android.permissioncontroller.permission.data.ServiceLiveData
import com.android.permissioncontroller.permission.data.SmartUpdateMediatorLiveData
import com.android.permissioncontroller.permission.data.UsageStatsLiveData
import com.android.permissioncontroller.permission.data.get
import com.android.permissioncontroller.permission.data.getUnusedPackages
import com.android.permissioncontroller.permission.model.livedatatypes.LightPackageInfo
import com.android.permissioncontroller.permission.service.revokeAppPermissions
import com.android.permissioncontroller.permission.utils.StringUtils
import com.android.permissioncontroller.permission.utils.Utils
import com.android.permissioncontroller.permission.utils.forEachInParallel
import kotlinx.coroutines.Dispatchers.Main
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.Job
import kotlinx.coroutines.launch
import java.util.Date
import java.util.Random
import java.util.concurrent.TimeUnit

private const val LOG_TAG = "HibernationPolicy"
const val DEBUG_OVERRIDE_THRESHOLDS = false
// TODO eugenesusla: temporarily enabled for extra logs during dogfooding
const val DEBUG_HIBERNATION_POLICY = true || DEBUG_OVERRIDE_THRESHOLDS

private var SKIP_NEXT_RUN = false

private val DEFAULT_UNUSED_THRESHOLD_MS = TimeUnit.DAYS.toMillis(90)

fun getUnusedThresholdMs() = when {
    DEBUG_OVERRIDE_THRESHOLDS -> TimeUnit.SECONDS.toMillis(1)
    else -> DeviceConfig.getLong(DeviceConfig.NAMESPACE_PERMISSIONS,
            Utils.PROPERTY_HIBERNATION_UNUSED_THRESHOLD_MILLIS,
            DEFAULT_UNUSED_THRESHOLD_MS)
}

private val DEFAULT_CHECK_FREQUENCY_MS = TimeUnit.DAYS.toMillis(15)

private fun getCheckFrequencyMs() = DeviceConfig.getLong(
    DeviceConfig.NAMESPACE_PERMISSIONS,
        Utils.PROPERTY_HIBERNATION_CHECK_FREQUENCY_MILLIS,
        DEFAULT_CHECK_FREQUENCY_MS)

private val PREF_KEY_FIRST_BOOT_TIME = "first_boot_time"

fun isHibernationEnabled(): Boolean {
    return SdkLevel.isAtLeastS() &&
        DeviceConfig.getBoolean(NAMESPACE_APP_HIBERNATION, Utils.PROPERTY_APP_HIBERNATION_ENABLED,
            true /* defaultValue */)
}

/**
 * Whether hibernation defaults on and affects apps that target pre-S. Has no effect if
 * [isHibernationEnabled] is false.
 */
fun hibernationTargetsPreSApps(): Boolean {
    return DeviceConfig.getBoolean(NAMESPACE_APP_HIBERNATION,
        Utils.PROPERTY_HIBERNATION_TARGETS_PRE_S_APPS,
        false /* defaultValue */)
}

/**
 * Receiver of the onBoot event.
 */
class HibernationOnBootReceiver : BroadcastReceiver() {

    override fun onReceive(context: Context, intent: Intent?) {
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "scheduleHibernationJob " +
                    "with frequency ${getCheckFrequencyMs()}ms " +
                    "and threshold ${getUnusedThresholdMs()}ms")
        }

        // Write first boot time if first boot
        context.firstBootTime

        // If this user is a profile, then its hibernation/auto-revoke will be handled by the
        // primary user
        if (isProfile(context)) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "user ${Process.myUserHandle().identifier} is a profile." +
                        " Not running hibernation job.")
            }
            return
        } else if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "user ${Process.myUserHandle().identifier} is a profile" +
                    "owner. Running hibernation job.")
        }

        if (isNewJobScheduleRequired(context)) {
            // periodic jobs normally run immediately, which is unnecessarily premature
            SKIP_NEXT_RUN = true
            val jobInfo = JobInfo.Builder(
                Constants.HIBERNATION_JOB_ID,
                ComponentName(context, HibernationJobService::class.java))
                .setPeriodic(getCheckFrequencyMs())
                // persist this job across boots
                .setPersisted(true)
                .build()
            val status = context.getSystemService(JobScheduler::class.java)!!.schedule(jobInfo)
            if (status != JobScheduler.RESULT_SUCCESS) {
                DumpableLog.e(LOG_TAG,
                    "Could not schedule ${HibernationJobService::class.java.simpleName}: $status")
            }
        }
    }

    // UserManager#isProfile was already a systemAPI, linter started complaining after it
    // was exposed as a public API thinking it was a newly exposed API.
    @SuppressLint("NewApi")
    private fun isProfile(context: Context): Boolean {
        val userManager = context.getSystemService(UserManager::class.java)!!
        return userManager.isProfile
    }

    /**
     * Returns whether a new job needs to be scheduled. A persisted job is used to keep the schedule
     * across boots, but that job needs to be scheduled a first time and whenever the check
     * frequency changes.
     */
    private fun isNewJobScheduleRequired(context: Context): Boolean {
        // check if the job is already scheduled or needs a change
        var scheduleNewJob = false
        val existingJob: JobInfo? = context.getSystemService(JobScheduler::class.java)!!
            .getPendingJob(Constants.HIBERNATION_JOB_ID)
        if (existingJob == null) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "No existing job, scheduling a new one")
            }
            scheduleNewJob = true
        } else if (existingJob.intervalMillis != getCheckFrequencyMs()) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Interval frequency has changed, updating job")
            }
            scheduleNewJob = true
        } else {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Job already scheduled.")
            }
        }
        return scheduleNewJob
    }
}

/**
 * Gets apps that are unused and should hibernate as a map of the user and their hibernateable apps.
 */
@MainThread
private suspend fun getAppsToHibernate(
    context: Context
): Map<UserHandle, List<LightPackageInfo>> {
    val now = System.currentTimeMillis()
    val firstBootTime = context.firstBootTime

    val allPackagesByUser = AllPackageInfosLiveData.getInitializedValue(forceUpdate = true)
    val allPackagesByUserByUid = allPackagesByUser.mapValues { (_, pkgs) ->
        pkgs.groupBy { pkg -> pkg.uid }
    }
    val unusedApps = allPackagesByUser.toMutableMap()

    val userStats = UsageStatsLiveData[getUnusedThresholdMs(),
        if (DEBUG_OVERRIDE_THRESHOLDS) INTERVAL_DAILY else INTERVAL_MONTHLY].getInitializedValue()
    if (DEBUG_HIBERNATION_POLICY) {
        for ((user, stats) in userStats) {
            DumpableLog.i(LOG_TAG, "Usage stats for user ${user.identifier}: " +
                    stats.map { stat ->
                        stat.packageName to Date(stat.lastTimePackageUsed())
                    }.toMap())
        }
    }
    for (user in unusedApps.keys.toList()) {
        if (user !in userStats.keys) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Ignoring user ${user.identifier}")
            }
            unusedApps.remove(user)
        }
    }

    for ((user, stats) in userStats) {
        var unusedUserApps = unusedApps[user] ?: continue

        unusedUserApps = unusedUserApps.filter { packageInfo ->
            val pkgName = packageInfo.packageName

            val uidPackages = allPackagesByUserByUid[user]!![packageInfo.uid]
                    ?.map { info -> info.packageName } ?: emptyList()
            if (pkgName !in uidPackages) {
                Log.wtf(LOG_TAG, "Package $pkgName not among packages for " +
                        "its uid ${packageInfo.uid}: $uidPackages")
            }
            var lastTimePkgUsed: Long = stats.lastTimePackageUsed(uidPackages)

            // Limit by install time
            lastTimePkgUsed = Math.max(lastTimePkgUsed, packageInfo.firstInstallTime)

            // Limit by first boot time
            lastTimePkgUsed = Math.max(lastTimePkgUsed, firstBootTime)

            // Handle cross-profile apps
            if (context.isPackageCrossProfile(pkgName)) {
                for ((otherUser, otherStats) in userStats) {
                    if (otherUser == user) {
                        continue
                    }
                    lastTimePkgUsed =
                        maxOf(lastTimePkgUsed, otherStats.lastTimePackageUsed(pkgName))
                }
            }

            // Threshold check - whether app is unused
            now - lastTimePkgUsed > getUnusedThresholdMs()
        }

        unusedApps[user] = unusedUserApps
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "Unused apps for user ${user.identifier}: " +
                    "${unusedUserApps.map { it.packageName }}")
        }
    }

    val appsToHibernate = mutableMapOf<UserHandle, List<LightPackageInfo>>()
    val userManager = context.getSystemService(UserManager::class.java)
    for ((user, userApps) in unusedApps) {
        if (userManager == null || !userManager.isUserUnlocked(user)) {
            DumpableLog.w(LOG_TAG, "Skipping $user - locked direct boot state")
            continue
        }
        var userAppsToHibernate = mutableListOf<LightPackageInfo>()
        userApps.forEachInParallel(Main) { pkg: LightPackageInfo ->
            if (isPackageHibernationExemptBySystem(pkg, user)) {
                return@forEachInParallel
            }

            if (isPackageHibernationExemptByUser(context, pkg)) {
                return@forEachInParallel
            }

            val packageName = pkg.packageName
            val packageImportance = context
                .getSystemService(ActivityManager::class.java)!!
                .getPackageImportance(packageName)
            if (packageImportance <= IMPORTANCE_CANT_SAVE_STATE) {
                // Process is running in a state where it should not be killed
                DumpableLog.i(LOG_TAG,
                    "Skipping hibernation - $packageName running with importance " +
                        "$packageImportance")
                return@forEachInParallel
            }

            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "unused app $packageName - last used on " +
                    userStats[user]?.lastTimePackageUsed(packageName)?.let(::Date))
            }

            synchronized(userAppsToHibernate) {
                userAppsToHibernate.add(pkg)
            }
        }
        appsToHibernate.put(user, userAppsToHibernate)
    }
    return appsToHibernate
}

/**
 * Gets the last time we consider the package used based off its usage stats. On pre-S devices
 * this looks at last time visible which tracks explicit usage. In S, we add component usage
 * which tracks various forms of implicit usage (e.g. service bindings).
 */
fun UsageStats.lastTimePackageUsed(): Long {
    var lastTimePkgUsed = this.lastTimeVisible
    if (SdkLevel.isAtLeastS()) {
        lastTimePkgUsed = maxOf(lastTimePkgUsed, this.lastTimeAnyComponentUsed)
    }
    return lastTimePkgUsed
}

private fun List<UsageStats>.lastTimePackageUsed(pkgNames: List<String>): Long {
    var result = 0L
    for (stat in this) {
        if (stat.packageName in pkgNames) {
            result = Math.max(result, stat.lastTimePackageUsed())
        }
    }
    return result
}

private fun List<UsageStats>.lastTimePackageUsed(pkgName: String): Long {
    return lastTimePackageUsed(listOf(pkgName))
}

/**
 * Checks if the given package is exempt from hibernation in a way that's not user-overridable
 */
suspend fun isPackageHibernationExemptBySystem(
    pkg: LightPackageInfo,
    user: UserHandle
): Boolean {
    if (!LauncherPackagesLiveData.getInitializedValue().contains(pkg.packageName)) {
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} - Package is not on launcher")
        }
        return true
    }
    if (!ExemptServicesLiveData[user]
            .getInitializedValue()[pkg.packageName]
            .isNullOrEmpty()) {
        return true
    }
    if (Utils.isUserDisabledOrWorkProfile(user)) {
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG,
                    "Exempted ${pkg.packageName} - $user is disabled or a work profile")
        }
        return true
    }

    val context = PermissionControllerApplication.get()
    if (context.getSystemService(DevicePolicyManager::class.java)!!.isDeviceManaged) {
        // TODO(b/237065504): Use proper system API to check if the device is financed in U.
        val isFinancedDevice = Settings.Global.getInt(
                context.contentResolver, "device_owner_type", 0) == 1
        if (!isFinancedDevice) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} - device is managed")
            }
            return true
        }
    }

    val carrierPrivilegedStatus = CarrierPrivilegedStatusLiveData[pkg.packageName]
            .getInitializedValue()
    if (carrierPrivilegedStatus != CARRIER_PRIVILEGE_STATUS_HAS_ACCESS &&
            carrierPrivilegedStatus != CARRIER_PRIVILEGE_STATUS_NO_ACCESS) {
        DumpableLog.w(LOG_TAG, "Error carrier privileged status for ${pkg.packageName}: " +
                carrierPrivilegedStatus)
    }
    if (carrierPrivilegedStatus == CARRIER_PRIVILEGE_STATUS_HAS_ACCESS) {
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} - carrier privileged")
        }
        return true
    }

    if (PermissionControllerApplication.get()
            .packageManager
            .checkPermission(
                    Manifest.permission.READ_PRIVILEGED_PHONE_STATE,
                    pkg.packageName) == PERMISSION_GRANTED) {
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} " +
                    "- holder of READ_PRIVILEGED_PHONE_STATE")
        }
        return true
    }

    if (SdkLevel.isAtLeastS()) {
        val hasInstallOrUpdatePermissions =
                context.checkPermission(
                        Manifest.permission.INSTALL_PACKAGES, -1 /* pid */, pkg.uid) ==
                                PERMISSION_GRANTED ||
                context.checkPermission(
                        Manifest.permission.INSTALL_PACKAGE_UPDATES, -1 /* pid */, pkg.uid) ==
                                PERMISSION_GRANTED
        val hasUpdatePackagesWithoutUserActionPermission =
                context.checkPermission(
                        UPDATE_PACKAGES_WITHOUT_USER_ACTION, -1 /* pid */, pkg.uid) ==
                                PERMISSION_GRANTED
        val isInstallerOfRecord =
                InstallerPackagesLiveData[user].getInitializedValue().contains(pkg.packageName) &&
                        hasUpdatePackagesWithoutUserActionPermission
        // Grant if app w/ privileged install/update permissions or app is an installer app that
        // updates packages without user action.
        if (hasInstallOrUpdatePermissions || isInstallerOfRecord) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} - installer app")
            }
            return true
        }

        val roleHolders = context.getSystemService(android.app.role.RoleManager::class.java)!!
                .getRoleHolders(RoleManager.ROLE_SYSTEM_WELLBEING)
        if (roleHolders.contains(pkg.packageName)) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} - wellbeing app")
            }
            return true
        }
    }

    if (SdkLevel.isAtLeastT()) {
        val roleHolders = context.getSystemService(android.app.role.RoleManager::class.java)!!
            .getRoleHolders(RoleManager.ROLE_DEVICE_POLICY_MANAGEMENT)
        if (roleHolders.contains(pkg.packageName)) {
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Exempted ${pkg.packageName} - device policy manager app")
            }
            return true
        }
    }

    return false
}

/**
 * Checks if the given package is exempt from hibernation/auto revoke in a way that's
 * user-overridable
 */
suspend fun isPackageHibernationExemptByUser(
    context: Context,
    pkg: LightPackageInfo
): Boolean {
    val packageName = pkg.packageName
    val packageUid = pkg.uid

    val allowlistAppOpMode =
        AppOpLiveData[packageName,
            AppOpsManager.OPSTR_AUTO_REVOKE_PERMISSIONS_IF_UNUSED, packageUid]
            .getInitializedValue()
    if (allowlistAppOpMode == AppOpsManager.MODE_DEFAULT) {
        // Initial state - allowlist not explicitly overridden by either user or installer
        if (DEBUG_OVERRIDE_THRESHOLDS) {
            // Suppress exemptions to allow debugging
            return false
        }

        if (hibernationTargetsPreSApps()) {
            // Default on if overridden
            return false
        }

        // Q- packages exempt by default, except R- on Auto since Auto-Revoke was skipped in R
        val maxTargetSdkVersionForExemptApps =
                if (context.packageManager.hasSystemFeature(PackageManager.FEATURE_AUTOMOTIVE)) {
                    android.os.Build.VERSION_CODES.R
                } else {
                    android.os.Build.VERSION_CODES.Q
                }

        return pkg.targetSdkVersion <= maxTargetSdkVersionForExemptApps
    }
    // Check whether user/installer exempt
    return allowlistAppOpMode != AppOpsManager.MODE_ALLOWED
}

private fun Context.isPackageCrossProfile(pkg: String): Boolean {
    return packageManager.checkPermission(
        Manifest.permission.INTERACT_ACROSS_PROFILES, pkg) == PERMISSION_GRANTED ||
        packageManager.checkPermission(
            Manifest.permission.INTERACT_ACROSS_USERS, pkg) == PERMISSION_GRANTED ||
        packageManager.checkPermission(
            Manifest.permission.INTERACT_ACROSS_USERS_FULL, pkg) == PERMISSION_GRANTED
}

val Context.sharedPreferences: SharedPreferences
    get() {
    return PreferenceManager.getDefaultSharedPreferences(this)
}

private val Context.firstBootTime: Long get() {
    var time = sharedPreferences.getLong(PREF_KEY_FIRST_BOOT_TIME, -1L)
    if (time > 0) {
        return time
    }
    // This is the first boot
    time = System.currentTimeMillis()
    sharedPreferences.edit().putLong(PREF_KEY_FIRST_BOOT_TIME, time).apply()
    return time
}

/**
 * A job to check for apps unused in the last [getUnusedThresholdMs]ms every
 * [getCheckFrequencyMs]ms and hibernate the app / revoke their runtime permissions.
 */
class HibernationJobService : JobService() {
    var job: Job? = null
    var jobStartTime: Long = -1L

    override fun onStartJob(params: JobParameters?): Boolean {
        if (DEBUG_HIBERNATION_POLICY) {
            DumpableLog.i(LOG_TAG, "onStartJob")
        }

        if (SKIP_NEXT_RUN) {
            SKIP_NEXT_RUN = false
            if (DEBUG_HIBERNATION_POLICY) {
                DumpableLog.i(LOG_TAG, "Skipping auto revoke first run when scheduled by system")
            }
            jobFinished(params, false)
            return true
        }

        jobStartTime = System.currentTimeMillis()
        job = GlobalScope.launch(Main) {
            try {
                var sessionId = Constants.INVALID_SESSION_ID
                while (sessionId == Constants.INVALID_SESSION_ID) {
                    sessionId = Random().nextLong()
                }

                val appsToHibernate = getAppsToHibernate(this@HibernationJobService)
                var hibernatedApps: Set<Pair<String, UserHandle>> = emptySet()
                if (isHibernationEnabled()) {
                    val hibernationController =
                        HibernationController(this@HibernationJobService, getUnusedThresholdMs(),
                            hibernationTargetsPreSApps())
                    hibernatedApps = hibernationController.hibernateApps(appsToHibernate)
                }
                val revokedApps = revokeAppPermissions(
                        appsToHibernate, this@HibernationJobService, sessionId)
                val unusedApps: Set<Pair<String, UserHandle>> = hibernatedApps + revokedApps
                if (unusedApps.isNotEmpty()) {
                    showUnusedAppsNotification(unusedApps.size, sessionId)
                }
            } catch (e: Exception) {
                DumpableLog.e(LOG_TAG, "Failed to auto-revoke permissions", e)
            }
            jobFinished(params, false)
        }
        return true
    }

    private suspend fun showUnusedAppsNotification(numUnused: Int, sessionId: Long) {
        val notificationManager = getSystemService(NotificationManager::class.java)!!

        val permissionReminderChannel = NotificationChannel(
                Constants.PERMISSION_REMINDER_CHANNEL_ID, getString(R.string.permission_reminders),
                NotificationManager.IMPORTANCE_LOW)
        notificationManager.createNotificationChannel(permissionReminderChannel)

        val clickIntent = Intent(Intent.ACTION_MANAGE_UNUSED_APPS).apply {
            putExtra(Constants.EXTRA_SESSION_ID, sessionId)
            flags = Intent.FLAG_ACTIVITY_NEW_TASK
        }
        val pendingIntent = PendingIntent.getActivity(this, 0, clickIntent,
            PendingIntent.FLAG_ONE_SHOT or PendingIntent.FLAG_UPDATE_CURRENT or
            PendingIntent.FLAG_IMMUTABLE)

        var notifTitle: String
        var notifContent: String
        if (isHibernationEnabled()) {
            notifTitle = StringUtils.getIcuPluralsString(this,
                R.string.unused_apps_notification_title, numUnused)
            notifContent = getString(R.string.unused_apps_notification_content)
        } else {
            notifTitle = getString(R.string.auto_revoke_permission_notification_title)
            notifContent = getString(R.string.auto_revoke_permission_notification_content)
        }

        // Notification won't appear on TV, because notifications are considered distruptive on TV
        val b = Notification.Builder(this, Constants.PERMISSION_REMINDER_CHANNEL_ID)
            .setContentTitle(notifTitle)
            .setContentText(notifContent)
            .setStyle(Notification.BigTextStyle().bigText(notifContent))
            .setSmallIcon(R.drawable.ic_settings_24dp)
            .setColor(getColor(android.R.color.system_notification_accent_color))
            .setAutoCancel(true)
            .setContentIntent(pendingIntent)
        Utils.getSettingsLabelForNotifications(applicationContext.packageManager)?.let {
            settingsLabel ->
            val extras = Bundle()
            extras.putString(Notification.EXTRA_SUBSTITUTE_APP_NAME, settingsLabel.toString())
            b.addExtras(extras)
        }

        notificationManager.notify(HibernationJobService::class.java.simpleName,
                Constants.UNUSED_APPS_NOTIFICATION_ID, b.build())
        // Preload the unused packages
        getUnusedPackages().getInitializedValue()
    }

    override fun onStopJob(params: JobParameters?): Boolean {
        DumpableLog.w(LOG_TAG, "onStopJob after ${System.currentTimeMillis() - jobStartTime}ms")
        job?.cancel()
        return true
    }
}

/**
 * Packages using exempt services for the current user (package-name -> list<service-interfaces>
 * implemented by the package)
 */
class ExemptServicesLiveData(private val user: UserHandle)
    : SmartUpdateMediatorLiveData<Map<String, List<String>>>() {
    private val serviceLiveDatas: List<SmartUpdateMediatorLiveData<Set<String>>> = listOf(
            ServiceLiveData[InputMethod.SERVICE_INTERFACE,
                    Manifest.permission.BIND_INPUT_METHOD,
                    user],
            ServiceLiveData[
                    NotificationListenerService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_NOTIFICATION_LISTENER_SERVICE,
                    user],
            ServiceLiveData[
                    AccessibilityService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_ACCESSIBILITY_SERVICE,
                    user],
            ServiceLiveData[
                    WallpaperService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_WALLPAPER,
                    user],
            ServiceLiveData[
                    VoiceInteractionService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_VOICE_INTERACTION,
                    user],
            ServiceLiveData[
                    PrintService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_PRINT_SERVICE,
                    user],
            ServiceLiveData[
                    DreamService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_DREAM_SERVICE,
                    user],
            ServiceLiveData[
                    AutofillService.SERVICE_INTERFACE,
                    Manifest.permission.BIND_AUTOFILL_SERVICE,
                    user],
            ServiceLiveData[
                    DevicePolicyManager.ACTION_DEVICE_ADMIN_SERVICE,
                    Manifest.permission.BIND_DEVICE_ADMIN,
                    user],
            BroadcastReceiverLiveData[
                    DeviceAdminReceiver.ACTION_DEVICE_ADMIN_ENABLED,
                    Manifest.permission.BIND_DEVICE_ADMIN,
                    user]
    )

    init {
        serviceLiveDatas.forEach { addSource(it) { update() } }
    }

    override fun onUpdate() {
        if (serviceLiveDatas.all { it.isInitialized }) {
            val pksToServices = mutableMapOf<String, MutableList<String>>()

            serviceLiveDatas.forEach { serviceLD ->
                serviceLD.value!!.forEach { packageName ->
                    pksToServices.getOrPut(packageName, { mutableListOf() })
                            .add((serviceLD as? HasIntentAction)?.intentAction ?: "???")
                }
            }

            value = pksToServices
        }
    }

    /**
     * Repository for ExemptServiceLiveData
     *
     * <p> Key value is user
     */
    companion object : DataRepositoryForPackage<UserHandle, ExemptServicesLiveData>() {
        override fun newValue(key: UserHandle): ExemptServicesLiveData {
            return ExemptServicesLiveData(key)
        }
    }
}

/**
 * Live data for whether the hibernation feature is enabled or not.
 */
object HibernationEnabledLiveData
    : MutableLiveData<Boolean>() {
    init {
        postValue(SdkLevel.isAtLeastS() &&
            DeviceConfig.getBoolean(NAMESPACE_APP_HIBERNATION,
            Utils.PROPERTY_APP_HIBERNATION_ENABLED, true /* defaultValue */))
        DeviceConfig.addOnPropertiesChangedListener(
            NAMESPACE_APP_HIBERNATION,
            PermissionControllerApplication.get().mainExecutor,
            { properties ->
                for (key in properties.keyset) {
                    if (key == Utils.PROPERTY_APP_HIBERNATION_ENABLED) {
                        value = SdkLevel.isAtLeastS() &&
                            properties.getBoolean(key, true /* defaultValue */)
                        break
                    }
                }
            }
        )
    }
}