Signal-iOS/SignalMessaging/Notifications/AppNotifications.swift

//
//  Copyright (c) 2020 Open Whisper Systems. All rights reserved.
//

import Foundation
import PromiseKit

/// There are two primary components in our system notification integration:
///
///     1. The `NotificationPresenter` shows system notifications to the user.
///     2. The `NotificationActionHandler` handles the users interactions with these
///        notifications.
///
/// The NotificationPresenter is driven by the adapter pattern to provide a unified interface to
/// presenting notifications on iOS9, which uses UINotifications vs iOS10+ which supports
/// UNUserNotifications.
///
/// The `NotificationActionHandler`s also need slightly different integrations for UINotifications
/// vs. UNUserNotifications, but because they are integrated at separate system defined callbacks,
/// there is no need for an Adapter, and instead the appropriate NotificationActionHandler is
/// wired directly into the appropriate callback point.

public enum AppNotificationCategory: CaseIterable {
    case incomingMessageWithActions
    case incomingMessageWithoutActions
    case incomingMessageFromNoLongerVerifiedIdentity
    case infoOrErrorMessage
    case threadlessErrorMessage
    case incomingCall
    case missedCallWithActions
    case missedCallWithoutActions
    case missedCallFromNoLongerVerifiedIdentity
    case grdbMigration
}

public enum AppNotificationAction: CaseIterable {
    case answerCall
    case callBack
    case declineCall
    case markAsRead
    case reply
    case showThread
}

public struct AppNotificationUserInfoKey {
    public static let threadId = "Signal.AppNotificationsUserInfoKey.threadId"
    public static let callBackUuid = "Signal.AppNotificationsUserInfoKey.callBackUuid"
    public static let callBackPhoneNumber = "Signal.AppNotificationsUserInfoKey.callBackPhoneNumber"
    public static let localCallId = "Signal.AppNotificationsUserInfoKey.localCallId"
}

extension AppNotificationCategory {
    var identifier: String {
        switch self {
        case .incomingMessageWithActions:
            return "Signal.AppNotificationCategory.incomingMessageWithActions"
        case .incomingMessageWithoutActions:
            return "Signal.AppNotificationCategory.incomingMessage"
        case .incomingMessageFromNoLongerVerifiedIdentity:
            return "Signal.AppNotificationCategory.incomingMessageFromNoLongerVerifiedIdentity"
        case .infoOrErrorMessage:
            return "Signal.AppNotificationCategory.infoOrErrorMessage"
        case .threadlessErrorMessage:
            return "Signal.AppNotificationCategory.threadlessErrorMessage"
        case .incomingCall:
            return "Signal.AppNotificationCategory.incomingCall"
        case .missedCallWithActions:
            return "Signal.AppNotificationCategory.missedCallWithActions"
        case .missedCallWithoutActions:
            return "Signal.AppNotificationCategory.missedCall"
        case .missedCallFromNoLongerVerifiedIdentity:
            return "Signal.AppNotificationCategory.missedCallFromNoLongerVerifiedIdentity"
        case .grdbMigration:
            return "Signal.AppNotificationCategory.grdbMigration"
        }
    }

    var actions: [AppNotificationAction] {
        switch self {
        case .incomingMessageWithActions:
            return [.markAsRead, .reply]
        case .incomingMessageWithoutActions:
            return []
        case .incomingMessageFromNoLongerVerifiedIdentity:
            return []
        case .infoOrErrorMessage:
            return []
        case .threadlessErrorMessage:
            return []
        case .incomingCall:
            return [.answerCall, .declineCall]
        case .missedCallWithActions:
            return [.callBack, .showThread]
        case .missedCallWithoutActions:
            return []
        case .missedCallFromNoLongerVerifiedIdentity:
            return []
        case .grdbMigration:
            return []
        }
    }
}

extension AppNotificationAction {
    var identifier: String {
        switch self {
        case .answerCall:
            return "Signal.AppNotifications.Action.answerCall"
        case .callBack:
            return "Signal.AppNotifications.Action.callBack"
        case .declineCall:
            return "Signal.AppNotifications.Action.declineCall"
        case .markAsRead:
            return "Signal.AppNotifications.Action.markAsRead"
        case .reply:
            return "Signal.AppNotifications.Action.reply"
        case .showThread:
            return "Signal.AppNotifications.Action.showThread"
        }
    }
}

// Delay notification of incoming messages when it's likely to be read by a linked device to
// avoid notifying a user on their phone while a conversation is actively happening on desktop.
let kNotificationDelayForRemoteRead: TimeInterval = 5

let kAudioNotificationsThrottleCount = 2
let kAudioNotificationsThrottleInterval: TimeInterval = 5

protocol NotificationPresenterAdaptee: class {

    func registerNotificationSettings() -> Promise<Void>

    func notify(category: AppNotificationCategory, title: String?, body: String, threadIdentifier: String?, userInfo: [AnyHashable: Any], sound: OWSSound?)

    func notify(category: AppNotificationCategory, title: String?, body: String, threadIdentifier: String?, userInfo: [AnyHashable: Any], sound: OWSSound?, replacingIdentifier: String?)

    func cancelNotifications(threadId: String)
    func clearAllNotifications()

    func notifyUserForGRDBMigration()

    var hasReceivedSyncMessageRecently: Bool { get }
}

extension NotificationPresenterAdaptee {
    var hasReceivedSyncMessageRecently: Bool {
        return OWSDeviceManager.shared().hasReceivedSyncMessage(inLastSeconds: 60)
    }
}

@objc(OWSNotificationPresenter)
public class NotificationPresenter: NSObject, NotificationsProtocol {
    private let adaptee: NotificationPresenterAdaptee

    @objc
    public override init() {
        self.adaptee = UserNotificationPresenterAdaptee()

        super.init()

        AppReadiness.runNowOrWhenAppDidBecomeReady {
            NotificationCenter.default.addObserver(self, selector: #selector(self.handleMessageRead), name: .incomingMessageMarkedAsRead, object: nil)
        }
        SwiftSingletons.register(self)
    }

    // MARK: - Dependencies

    var contactsManager: OWSContactsManager {
        return Environment.shared.contactsManager
    }

    var identityManager: OWSIdentityManager {
        return OWSIdentityManager.shared()
    }

    var preferences: OWSPreferences {
        return Environment.shared.preferences
    }

    var previewType: NotificationType {
        return preferences.notificationPreviewType()
    }

    var shouldShowActions: Bool {
        return previewType == .namePreview
    }

    // MARK: -

    @objc
    public func handleMessageRead(notification: Notification) {
        AssertIsOnMainThread()

        switch notification.object {
        case let incomingMessage as TSIncomingMessage:
            Logger.debug("canceled notification for message: \(incomingMessage)")
            cancelNotifications(threadId: incomingMessage.uniqueThreadId)
        default:
            break
        }
    }

    // MARK: - Presenting Notifications

    public func registerNotificationSettings() -> Promise<Void> {
        return adaptee.registerNotificationSettings()
    }

    public func presentIncomingCall(_ call: SignalCall, callerName: String) {

        let remoteAddress = call.remoteAddress
        let thread = TSContactThread.getOrCreateThread(contactAddress: remoteAddress)

        let notificationTitle: String?
        let threadIdentifier: String?
        switch previewType {
        case .noNameNoPreview:
            notificationTitle = nil
            threadIdentifier = nil
        case .nameNoPreview, .namePreview:
            notificationTitle = callerName
            threadIdentifier = thread.uniqueId
        }
        let notificationBody = NotificationStrings.incomingCallBody
        let userInfo = [
            AppNotificationUserInfoKey.threadId: thread.uniqueId,
            AppNotificationUserInfoKey.localCallId: call.localId.uuidString
        ]

        DispatchQueue.main.async {
            self.adaptee.notify(category: .incomingCall,
                                title: notificationTitle,
                                body: notificationBody,
                                threadIdentifier: threadIdentifier,
                                userInfo: userInfo,
                                sound: .defaultiOSIncomingRingtone,
                                replacingIdentifier: call.localId.uuidString)
        }
    }

    public func presentMissedCall(_ call: SignalCall, callerName: String) {

        let remoteAddress = call.remoteAddress
        let thread = TSContactThread.getOrCreateThread(contactAddress: remoteAddress)

        let notificationTitle: String?
        let threadIdentifier: String?
        switch previewType {
        case .noNameNoPreview:
            notificationTitle = nil
            threadIdentifier = nil
        case .nameNoPreview, .namePreview:
            notificationTitle = callerName
            threadIdentifier = thread.uniqueId
        }
        let notificationBody = NotificationStrings.missedCallBody
        let userInfo = userInfoForMissedCall(thread: thread, remoteAddress: remoteAddress)

        let category: AppNotificationCategory = (shouldShowActions
            ? .missedCallWithActions
            : .missedCallWithoutActions)
        DispatchQueue.main.async {
            let sound = self.requestSound(thread: thread)
            self.adaptee.notify(category: category,
                                title: notificationTitle,
                                body: notificationBody,
                                threadIdentifier: threadIdentifier,
                                userInfo: userInfo,
                                sound: sound,
                                replacingIdentifier: call.localId.uuidString)
        }
    }

    public func presentMissedCallBecauseOfNoLongerVerifiedIdentity(call: SignalCall, callerName: String) {

        let remoteAddress = call.remoteAddress
        let thread = TSContactThread.getOrCreateThread(contactAddress: remoteAddress)

        let notificationTitle: String?
        let threadIdentifier: String?
        switch previewType {
        case .noNameNoPreview:
            notificationTitle = nil
            threadIdentifier = nil
        case .nameNoPreview, .namePreview:
            notificationTitle = callerName
            threadIdentifier = thread.uniqueId
        }
        let notificationBody = NotificationStrings.missedCallBecauseOfIdentityChangeBody
        let userInfo = [
            AppNotificationUserInfoKey.threadId: thread.uniqueId
        ]

        DispatchQueue.main.async {
            let sound = self.requestSound(thread: thread)
            self.adaptee.notify(category: .missedCallFromNoLongerVerifiedIdentity,
                                title: notificationTitle,
                                body: notificationBody,
                                threadIdentifier: threadIdentifier,
                                userInfo: userInfo,
                                sound: sound,
                                replacingIdentifier: call.localId.uuidString)
        }
    }

    public func presentMissedCallBecauseOfNewIdentity(call: SignalCall, callerName: String) {

        let remoteAddress = call.remoteAddress
        let thread = TSContactThread.getOrCreateThread(contactAddress: remoteAddress)

        let notificationTitle: String?
        let threadIdentifier: String?
        switch previewType {
        case .noNameNoPreview:
            notificationTitle = nil
            threadIdentifier = nil
        case .nameNoPreview, .namePreview:
            notificationTitle = callerName
            threadIdentifier = thread.uniqueId
        }
        let notificationBody = NotificationStrings.missedCallBecauseOfIdentityChangeBody
        let userInfo = userInfoForMissedCall(thread: thread, remoteAddress: remoteAddress)

        let category: AppNotificationCategory = (shouldShowActions
            ? .missedCallWithActions
            : .missedCallWithoutActions)
        DispatchQueue.main.async {
            let sound = self.requestSound(thread: thread)
            self.adaptee.notify(category: category,
                                title: notificationTitle,
                                body: notificationBody,
                                threadIdentifier: threadIdentifier,
                                userInfo: userInfo,
                                sound: sound,
                                replacingIdentifier: call.localId.uuidString)
        }
    }

    private func userInfoForMissedCall(thread: TSThread, remoteAddress: SignalServiceAddress) -> [String: Any] {
        var userInfo: [String: Any] = [
            AppNotificationUserInfoKey.threadId: thread.uniqueId
        ]
        if let uuid = remoteAddress.uuid {
            userInfo[AppNotificationUserInfoKey.callBackUuid] = uuid.uuidString
        }
        if let phoneNumber = remoteAddress.phoneNumber {
            userInfo[AppNotificationUserInfoKey.callBackPhoneNumber] = phoneNumber
        }
        return userInfo
    }

    public func notifyUser(for incomingMessage: TSIncomingMessage, in thread: TSThread, transaction: SDSAnyReadTransaction) {

        guard !thread.isMuted else {
            return
        }

        // While batch processing, some of the necessary changes have not been commited.
        let rawMessageText = incomingMessage.previewText(with: transaction)

        let messageText = rawMessageText.filterStringForDisplay()

        let senderName = contactsManager.displayName(for: incomingMessage.authorAddress, transaction: transaction)

        let notificationTitle: String?
        let threadIdentifier: String?
        switch previewType {
        case .noNameNoPreview:
            notificationTitle = nil
            threadIdentifier = nil
        case .nameNoPreview, .namePreview:
            switch thread {
            case is TSContactThread:
                notificationTitle = senderName
            case let groupThread as TSGroupThread:
                notificationTitle = String(format: NotificationStrings.incomingGroupMessageTitleFormat,
                                           senderName,
                                           groupThread.groupNameOrDefault)
            default:
                owsFailDebug("unexpected thread: \(thread)")
                return
            }

            threadIdentifier = thread.uniqueId
        }

        let notificationBody: String?
        switch previewType {
        case .noNameNoPreview, .nameNoPreview:
            notificationBody = NotificationStrings.incomingMessageBody
        case .namePreview:
            notificationBody = messageText
        }
        assert((notificationBody ?? notificationTitle) != nil)

        // Don't reply from lockscreen if anyone in this conversation is
        // "no longer verified".
        var didIdentityChange = false
        for address in thread.recipientAddresses {
            if self.identityManager.verificationState(for: address) == .noLongerVerified {
                didIdentityChange = true
                break
            }
        }

        let category: AppNotificationCategory
        if didIdentityChange {
            category = .incomingMessageFromNoLongerVerifiedIdentity
        } else if !shouldShowActions {
            category = .incomingMessageWithoutActions
        } else {
            category = .incomingMessageWithActions
        }
        let userInfo = [
            AppNotificationUserInfoKey.threadId: thread.uniqueId
        ]

        DispatchQueue.main.async {
            let sound = self.requestSound(thread: thread)
            self.adaptee.notify(category: category,
                                title: notificationTitle,
                                body: notificationBody ?? "",
                                threadIdentifier: threadIdentifier,
                                userInfo: userInfo,
                                sound: sound)
        }
    }

    public func notifyUser(for reaction: OWSReaction, on message: TSOutgoingMessage, in thread: TSThread, transaction: SDSAnyReadTransaction) {

        guard !thread.isMuted else { return }

        // Reaction notifications only get displayed if we can
        // include the reaction details, otherwise we don't
        // disturb the user for a non-message
        guard previewType == .namePreview else { return }

        let senderName = contactsManager.displayName(for: reaction.reactor, transaction: transaction)

        let notificationTitle: String

        switch thread {
        case is TSContactThread:
            notificationTitle = senderName
        case let groupThread as TSGroupThread:
            notificationTitle = String(
                format: NotificationStrings.incomingGroupMessageTitleFormat,
                senderName,
                groupThread.groupNameOrDefault
            )
        default:
            owsFailDebug("unexpected thread: \(thread)")
            return
        }

        let notificationBody: String
        if let bodyDescription: String = {
            if let messageBody = message.body, !messageBody.isEmpty {
                return messageBody.filterStringForDisplay()
            } else if let oversizeText = message.oversizeText(with: transaction), !oversizeText.isEmpty {
                return oversizeText.filterStringForDisplay()
            } else {
                return nil
            }
        }() {
            notificationBody = String(format: NotificationStrings.incomingReactionTextMessageFormat, reaction.emoji, bodyDescription)
        } else if message.isViewOnceMessage {
            notificationBody = String(format: NotificationStrings.incomingReactionViewOnceMessageFormat, reaction.emoji)
        } else if message.messageSticker != nil {
            notificationBody = String(format: NotificationStrings.incomingReactionStickerMessageFormat, reaction.emoji)
        } else if message.contactShare != nil {
            notificationBody = String(format: NotificationStrings.incomingReactionContactShareMessageFormat, reaction.emoji)
        } else if message.hasAttachments() {
            let mediaAttachments = message.mediaAttachments(with: transaction)
            let firstAttachment = mediaAttachments.first

            if mediaAttachments.count > 1 {
                notificationBody = String(format: NotificationStrings.incomingReactionAlbumMessageFormat, reaction.emoji)
            } else if firstAttachment?.isImage == true {
                notificationBody = String(format: NotificationStrings.incomingReactionPhotoMessageFormat, reaction.emoji)
            } else if firstAttachment?.isVideo == true {
                notificationBody = String(format: NotificationStrings.incomingReactionVideoMessageFormat, reaction.emoji)
            } else if firstAttachment?.isVoiceMessage == true {
                notificationBody = String(format: NotificationStrings.incomingReactionVoiceMessageFormat, reaction.emoji)
            } else if firstAttachment?.isAudio == true {
                notificationBody = String(format: NotificationStrings.incomingReactionAudioMessageFormat, reaction.emoji)
            } else if firstAttachment?.isAnimated == true {
                notificationBody = String(format: NotificationStrings.incomingReactionGifMessageFormat, reaction.emoji)
            } else {
                notificationBody = String(format: NotificationStrings.incomingReactionFileMessageFormat, reaction.emoji)
            }
        } else {
            notificationBody = String(format: NotificationStrings.incomingReactionFormat, reaction.emoji)
        }

        // Don't reply from lockscreen if anyone in this conversation is
        // "no longer verified".
        var didIdentityChange = false
        for address in thread.recipientAddresses {
            if self.identityManager.verificationState(for: address) == .noLongerVerified {
                didIdentityChange = true
                break
            }
        }

        let category: AppNotificationCategory
        if didIdentityChange {
            category = .incomingMessageFromNoLongerVerifiedIdentity
        } else if !shouldShowActions {
            category = .incomingMessageWithoutActions
        } else {
            category = .incomingMessageWithActions
        }
        let userInfo = [
            AppNotificationUserInfoKey.threadId: thread.uniqueId
        ]

        DispatchQueue.main.async {
            let sound = self.requestSound(thread: thread)
            self.adaptee.notify(
                category: category,
                title: notificationTitle,
                body: notificationBody,
                threadIdentifier: thread.uniqueId,
                userInfo: userInfo,
                sound: sound
            )
        }
    }

    public func notifyForFailedSend(inThread thread: TSThread) {
        let notificationTitle: String?
        switch previewType {
        case .noNameNoPreview:
            notificationTitle = nil
        case .nameNoPreview, .namePreview:
            notificationTitle = contactsManager.displayNameWithSneakyTransaction(thread: thread)
        }

        let notificationBody = NotificationStrings.failedToSendBody
        let threadId = thread.uniqueId
        let userInfo = [
            AppNotificationUserInfoKey.threadId: threadId
        ]

        DispatchQueue.main.async {
            let sound = self.requestSound(thread: thread)
            self.adaptee.notify(category: .infoOrErrorMessage,
                                title: notificationTitle,
                                body: notificationBody,
                                threadIdentifier: nil, // show ungrouped
                                userInfo: userInfo,
                                sound: sound)
        }
    }

    public func notifyUser(for errorMessage: TSErrorMessage, thread: TSThread, transaction: SDSAnyWriteTransaction) {
        notifyUser(for: errorMessage as TSMessage, thread: thread, wantsSound: true, transaction: transaction)
    }

    public func notifyUser(for infoMessage: TSInfoMessage, thread: TSThread, wantsSound: Bool, transaction: SDSAnyWriteTransaction) {
        notifyUser(for: infoMessage as TSMessage, thread: thread, wantsSound: wantsSound, transaction: transaction)
    }

    private func notifyUser(for infoOrErrorMessage: TSMessage, thread: TSThread, wantsSound: Bool, transaction: SDSAnyWriteTransaction) {

        let notificationTitle: String?
        let threadIdentifier: String?
        switch self.previewType {
        case .noNameNoPreview:
            notificationTitle = nil
            threadIdentifier = nil
        case .namePreview, .nameNoPreview:
            notificationTitle = contactsManager.displayName(for: thread, transaction: transaction)
            threadIdentifier = thread.uniqueId
        }

        let notificationBody: String
        switch previewType {
        case .noNameNoPreview, .nameNoPreview:
            notificationBody = NotificationStrings.incomingMessageBody
        case .namePreview:
            notificationBody = infoOrErrorMessage.previewText(with: transaction)
        }

        let threadId = thread.uniqueId
        let userInfo = [
            AppNotificationUserInfoKey.threadId: threadId
        ]

        transaction.addAsyncCompletion {
            let sound = wantsSound ? self.requestSound(thread: thread) : nil
            self.adaptee.notify(category: .infoOrErrorMessage,
                                title: notificationTitle,
                                body: notificationBody,
                                threadIdentifier: threadIdentifier,
                                userInfo: userInfo,
                                sound: sound)
        }
    }

    public func notifyUser(for errorMessage: ThreadlessErrorMessage, transaction: SDSAnyWriteTransaction) {
        let notificationBody = errorMessage.previewText(with: transaction)

        transaction.addAsyncCompletion {
            let sound = self.checkIfShouldPlaySound() ? OWSSounds.globalNotificationSound() : nil
            self.adaptee.notify(category: .threadlessErrorMessage,
                                title: nil,
                                body: notificationBody,
                                threadIdentifier: nil,
                                userInfo: [:],
                                sound: sound)
        }
    }

    @objc
    public func cancelNotifications(threadId: String) {
        adaptee.cancelNotifications(threadId: threadId)
    }

    @objc
    public func clearAllNotifications() {
        adaptee.clearAllNotifications()
    }

    @objc
    public func notifyUserForGRDBMigration() {
        adaptee.notifyUserForGRDBMigration()
    }

    // MARK: -

    var mostRecentNotifications = TruncatedList<UInt64>(maxLength: kAudioNotificationsThrottleCount)

    private func requestSound(thread: TSThread) -> OWSSound? {
        guard checkIfShouldPlaySound() else {
            return nil
        }

        return OWSSounds.notificationSound(for: thread)
    }

    private func checkIfShouldPlaySound() -> Bool {
        AssertIsOnMainThread()

        guard CurrentAppContext().isMainAppAndActive else {
            return true
        }

        guard preferences.soundInForeground() else {
            return false
        }

        let now = NSDate.ows_millisecondTimeStamp()
        let recentThreshold = now - UInt64(kAudioNotificationsThrottleInterval * Double(kSecondInMs))

        let recentNotifications = mostRecentNotifications.filter { $0 > recentThreshold }

        guard recentNotifications.count < kAudioNotificationsThrottleCount else {
            return false
        }

        mostRecentNotifications.append(now)
        return true
    }
}

struct TruncatedList<Element> {
    let maxLength: Int
    private var contents: [Element] = []

    init(maxLength: Int) {
        self.maxLength = maxLength
    }

    mutating func append(_ newElement: Element) {
        var newElements = self.contents
        newElements.append(newElement)
        self.contents = Array(newElements.suffix(maxLength))
    }
}

extension TruncatedList: Collection {
    typealias Index = Int

    var startIndex: Index {
        return contents.startIndex
    }

    var endIndex: Index {
        return contents.endIndex
    }

    subscript (position: Index) -> Element {
        return contents[position]
    }

    func index(after i: Index) -> Index {
        return contents.index(after: i)
    }
}