import Foundation
import monalxmpp

final class MonalXmppWrapper: ObservableObject {
    @Published private(set) var accountsAvailability: AccountsAvailability = .noAccounts
    @Published private(set) var accounts: [Account] = []
    @Published private(set) var contacts: [Contact] = []

    private let xmpp: MLXMPPManager
    private let db: DataLayer

    private var notificationObservers: [AnyObject] = []

    init() {
        // here is some inits (just for now)
        MLProcessLock.initialize(forProcess: "MainApp")

        // init monalxmpp components
        xmpp = MLXMPPManager.sharedInstance()
        db = DataLayer.sharedInstance()

        // subscribe to monalxmpp notifications and fire notification for update
        subscribeToUpdates()
        NotificationCenter.default.post(name: Notification.Name(kMonalRefresh), object: nil)
    }

    deinit {
        notificationObservers.forEach { NotificationCenter.default.removeObserver($0) }
    }
}

// MARK: - Public
extension MonalXmppWrapper {
    func tryLogin(_ login: String, _ password: String) async throws {
        let loginObject = LoginTry(xmpp: xmpp)
        let result = await loginObject.tryLogin(login, password)
        if !result {
            throw AimErrors.loginError
        } else {
            NotificationCenter.default.post(name: Notification.Name(kMonalRefresh), object: nil)
        }
    }

    func addContact(contactJid: String, forAccountID: Int) async {
        let contact = MLContact.createContact(fromJid: contactJid, andAccountID: NSNumber(value: forAccountID))
        xmpp.add(contact)
    }

    func deleteContact(_ contact: Contact) async throws {
        if let mlContact = db.contactList().first(where: { $0.contactJid == contact.contactJid }) {
            xmpp.remove(mlContact)
        } else {
            throw AimErrors.contactRemoveError
        }
    }
}

// MARK: - Try login from Login screen
private final class LoginTry {
    weak var xmpp: MLXMPPManager?

    var successObserver: AnyObject?
    var failureObserver: AnyObject?

    init(xmpp: MLXMPPManager) {
        self.xmpp = xmpp
    }

    // TODO: Добавить автовключение отключенных аккаунтов при попытке ввести тот же JID
    // Обработать кейс когда бесячий monalxmpp возвращает nil при попытке добавить тот же JID
    func tryLogin(_ login: String, _ password: String) async -> Bool {
        async let notify = await withCheckedContinuation { [weak self] continuation in
            self?.successObserver = NotificationCenter.default.addObserver(forName: Notification.Name("kMLResourceBoundNotice"), object: nil, queue: .main) { notification in
                print(notification.debugDescription)
                continuation.resume(returning: true)
            }
            self?.failureObserver = NotificationCenter.default.addObserver(forName: Notification.Name("kXMPPError"), object: nil, queue: .main) { notification in
                print(notification.debugDescription)
                continuation.resume(returning: false)
            }
        }

        defer {
            if let successObserver {
                NotificationCenter.default.removeObserver(successObserver)
            }
            if let failureObserver {
                NotificationCenter.default.removeObserver(failureObserver)
            }
        }

        let accountNumber = xmpp?.login(login, password: password)
        let result = await notify
        if let accountNumber, !result {
            xmpp?.removeAccount(forAccountID: accountNumber)
        }

        return result
    }
}

// MARK: - Handle notifications
private extension MonalXmppWrapper {
    func subscribeToUpdates() {
        // General
        let generalRefresh = NotificationCenter.default.addObserver(forName: Notification.Name(kMonalRefresh), object: nil, queue: .main) { [weak self] _ in
            self?.refreshAccounts()
            self?.refreshContacts()
        }
        notificationObservers.append(generalRefresh)

        // For contacts
        let contactRefresh = NotificationCenter.default.addObserver(forName: Notification.Name(kMonalContactRefresh), object: nil, queue: .main) { [weak self] _ in
            self?.refreshContacts()
        }
        let contactRemove = NotificationCenter.default.addObserver(forName: Notification.Name(kMonalContactRemoved), object: nil, queue: .main) { [weak self] _ in
            self?.refreshContacts()
        }
        notificationObservers.append(contentsOf: [contactRefresh, contactRemove])
    }

    func refreshAccounts() {
        let accounts = db.accountList()
            .compactMap { dict -> Account? in
                guard let dict = dict as? NSDictionary else { return nil }
                return Account(dict)
            }
        self.accounts = accounts
        xmpp.connectIfNecessary()

        // mark accounts availability
        if accounts.isEmpty {
            accountsAvailability = .noAccounts
        } else if accounts.filter({ $0.isEnabled }).isEmpty {
            accountsAvailability = .allDisabled
        } else {
            accountsAvailability = .someEnabled
        }
    }

    func refreshContacts() {
        contacts = db.contactList()
            .filter { $0.isSubscribedTo || $0.hasOutgoingContactRequest || $0.isSubscribedFrom }
            .filter { !$0.isSelfChat } // removed for now
            .compactMap { Contact($0) }
    }
}