//
//  NotificationService.swift
//  SimpleX NSE
//
//  Created by Evgeny on 26/04/2022.
//  Copyright © 2022 SimpleX Chat. All rights reserved.
//

import UserNotifications
import OSLog
import SimpleXChat

let logger = Logger()

let suspendingDelay: UInt64 = 2_000_000_000

class NotificationService: UNNotificationServiceExtension {
    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        logger.debug("NotificationService.didReceive")
        bestAttemptContent = request.content
        self.contentHandler = contentHandler
        let appState = appStateGroupDefault.get()
        switch appState {
        case .suspended:
            logger.debug("NotificationService: app is suspended")
            receiveNtfMessages(request, contentHandler)
        case .suspending:
            logger.debug("NotificationService: app is suspending")
            Task {
                var state = appState
                for _ in 1...5 {
                    _ = try await Task.sleep(nanoseconds: suspendingDelay)
                    state = appStateGroupDefault.get()
                    if state == .suspended || state != .suspending { break }
                }
                logger.debug("NotificationService: app state is \(state.rawValue, privacy: .public)")
                if state.inactive {
                    receiveNtfMessages(request, contentHandler)
                } else {
                    contentHandler(request.content)
                }
            }
        default:
            logger.debug("NotificationService: app state is \(appState.rawValue, privacy: .public)")
            contentHandler(request.content)
        }
    }

    func receiveNtfMessages(_ request: UNNotificationRequest, _ contentHandler: @escaping (UNNotificationContent) -> Void) {
        logger.debug("NotificationService: receiveNtfMessages")
        if case .documents = dbContainerGroupDefault.get() {
            contentHandler(request.content)
            return
        }
        let userInfo = request.content.userInfo
        if let ntfData = userInfo["notificationData"] as? [AnyHashable : Any],
           let nonce = ntfData["nonce"] as? String,
           let encNtfInfo = ntfData["message"] as? String,
           let _ = startChat() {
            logger.debug("NotificationService: receiveNtfMessages: chat is started")
            if let ntfMsgInfo = apiGetNtfMessage(nonce: nonce, encNtfInfo: encNtfInfo) {
                logger.debug("NotificationService: receiveNtfMessages: apiGetNtfMessage \(String(describing: ntfMsgInfo), privacy: .public)")
                if let connEntity = ntfMsgInfo.connEntity {
                    bestAttemptContent = createConnectionEventNtf(connEntity)
                }
                if let content = receiveMessageForNotification() {
                    logger.debug("NotificationService: receiveMessageForNotification: has message")
                    contentHandler(content)
                } else if let content = bestAttemptContent {
                    logger.debug("NotificationService: receiveMessageForNotification: no message")
                    contentHandler(content)
                }
            }
        }
    }

    override func serviceExtensionTimeWillExpire() {
        logger.debug("NotificationService.serviceExtensionTimeWillExpire")
        // Called just before the extension will be terminated by the system.
        // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
        if let contentHandler = self.contentHandler, let content = bestAttemptContent {
            contentHandler(content)
        }
    }
}

func startChat() -> User? {
    hs_init(0, nil)
    if let user = apiGetActiveUser() {
        logger.debug("active user \(String(describing: user))")
        do {
            try apiStartChat()
            try apiSetFilesFolder(filesFolder: getAppFilesDirectory().path)
            chatLastStartGroupDefault.set(Date.now)
            return user
        } catch {
            logger.error("NotificationService startChat error: \(responseError(error), privacy: .public)")
        }
    } else {
        logger.debug("no active user")
    }
    return nil
}

func receiveMessageForNotification() -> UNNotificationContent? {
    logger.debug("NotificationService receiveMessages started")
    while true {
        if let res = recvSimpleXMsg() {
            logger.debug("NotificationService receiveMessages: \(res.responseType)")
            switch res {
            case let .contactConnected(contact):
                return createContactConnectedNtf(contact)
    //        case let .contactConnecting(contact):
    //            TODO profile update
            case let .receivedContactRequest(contactRequest):
                return createContactRequestNtf(contactRequest)
            case let .newChatItem(aChatItem):
                let cInfo = aChatItem.chatInfo
                var cItem = aChatItem.chatItem
                if case .image = cItem.content.msgContent {
                   if let file = cItem.file,
                      file.fileSize <= maxImageSize,
                      privacyAcceptImagesGroupDefault.get() {
                       cItem = apiReceiveFile(fileId: file.fileId)?.chatItem ?? cItem
                   }
                }
                return createMessageReceivedNtf(cInfo, cItem)
    //        case let .rcvFileComplete(aChatItem):
    //            TODO file received?
    //            let cInfo = aChatItem.chatInfo
    //            let cItem = aChatItem.chatItem
    //            NtfManager.shared.notifyMessageReceived(cInfo, cItem)
            default:
                logger.debug("NotificationService ignored event: \(res.responseType)")
            }
        } else {
            return nil
        }
    }
}

func apiGetActiveUser() -> User? {
    let _ = getChatCtrl()
    let r = sendSimpleXCmd(.showActiveUser)
    logger.debug("apiGetActiveUser sendSimpleXCmd responce: \(String(describing: r))")
    switch r {
    case let .activeUser(user): return user
    case .chatCmdError(.error(.noActiveUser)): return nil
    default:
        logger.error("NotificationService apiGetActiveUser unexpected response: \(String(describing: r))")
        return nil
    }
}

func apiStartChat() throws {
    let r = sendSimpleXCmd(.startChat(subscribe: false))
    switch r {
    case .chatStarted: return
    case .chatRunning: return
    default: throw r
    }
}

func apiSetFilesFolder(filesFolder: String) throws {
    let r = sendSimpleXCmd(.setFilesFolder(filesFolder: filesFolder))
    if case .cmdOk = r { return }
    throw r
}

func apiGetNtfMessage(nonce: String, encNtfInfo: String) -> NtfMessages? {
    let r = sendSimpleXCmd(.apiGetNtfMessage(nonce: nonce, encNtfInfo: encNtfInfo))
    if case let .ntfMessages(connEntity, msgTs, ntfMessages) = r {
        return NtfMessages(connEntity: connEntity, msgTs: msgTs, ntfMessages: ntfMessages)
    }
    logger.debug("apiGetNtfMessage ignored response: \(String.init(describing: r), privacy: .public)")
    return nil
}

func apiReceiveFile(fileId: Int64) -> AChatItem? {
    let r = sendSimpleXCmd(.receiveFile(fileId: fileId))
    if case let .rcvFileAccepted(chatItem) = r { return chatItem }
    logger.error("receiveFile error: \(responseError(r))")
    return nil
}

struct NtfMessages {
    var connEntity: ConnectionEntity?
    var msgTs: Date?
    var ntfMessages: [NtfMsgInfo]
}