import Foundation
#if canImport(SocketIO)
import SocketIO
#endif

final class SocketService {
    static let shared = SocketService()

    private let syncQueue = DispatchQueue(label: "org.yobble.socket.service")
    private var currentToken: String?
    private var currentAuthPayload: [String: Any] = [:]

    #if canImport(SocketIO)
    private var manager: SocketManager?
    private var socket: SocketIOClient?
    #endif

    private init() {}

    func connectForCurrentUser() {
        syncQueue.async { [weak self] in
            guard let self else { return }
            guard let token = self.resolveCurrentAccessToken() else {
                if AppConfig.DEBUG { print("[SocketService] No access token available, disconnecting") }
                self.currentToken = nil
                self.disconnectInternal()
                return
            }

            self.connectInternal(with: token)
        }
    }

    func connect(withToken token: String) {
        syncQueue.async { [weak self] in
            self?.connectInternal(with: token)
        }
    }

    func disconnect() {
        syncQueue.async { [weak self] in
            guard let self else { return }
            self.currentToken = nil
            self.disconnectInternal()
        }
    }

    private func resolveCurrentAccessToken() -> String? {
        guard
            let login = UserDefaults.standard.string(forKey: "currentUser"),
            !login.isEmpty
        else {
            return nil
        }

        return KeychainService.shared.get(forKey: "access_token", service: login)
    }

    private func connectInternal(with token: String) {
        #if canImport(SocketIO)
        if token == currentToken,
           let socket,
           socket.status == .connected || socket.status == .connecting {
            if AppConfig.DEBUG { print("[SocketService] Already connected with current token") }
            return
        }

        currentToken = token
        currentAuthPayload = ["token": token]
        setupSocket(with: token)
        socket?.connect(withPayload: currentAuthPayload)
        #else
        if AppConfig.DEBUG {
            print("[SocketService] SocketIO framework not available; skipping connection")
        }
        #endif
    }

    #if canImport(SocketIO)
    private func setupSocket(with token: String) {
        guard let baseURL = URL(string: AppConfig.API_SERVER) else {
            if AppConfig.DEBUG { print("[SocketService] Invalid socket URL: \(AppConfig.API_SERVER)") }
            return
        }

        disconnectInternal()

        let configuration: SocketIOClientConfiguration = [
            .log(AppConfig.DEBUG),
            .compress,
            .secure(AppConfig.PROTOCOL.lowercased() == "https"),
            .path(AppConfig.SOCKET_PATH),
            .reconnects(true),
            .reconnectWait(2),
            .forceWebsockets(true),
            .extraHeaders([
                "Authorization": "Bearer \(token)",
                "User-Agent": AppConfig.USER_AGENT
            ]),
            .connectParams(["token": token])
        ]

        let manager = SocketManager(socketURL: baseURL, config: configuration)
        manager.handleQueue = syncQueue
        let socket = manager.defaultSocket

        if AppConfig.DEBUG {
            socket.onAny { event in
                print("[SocketService] onAny event=\(event.event) data=\(event.items ?? [])")
            }
        }

        socket.on(clientEvent: .connect) { _, _ in
            if AppConfig.DEBUG { print("[SocketService] Connected") }
        }

        socket.on(clientEvent: .disconnect) { data, _ in
            if AppConfig.DEBUG { print("[SocketService] Disconnected: \(data)") }
        }

        socket.on(clientEvent: .error) { data, _ in
            if AppConfig.DEBUG { print("[SocketService] Error: \(data)") }
        }

        self.manager = manager
        self.socket = socket
    }

    private func disconnectInternal() {
        socket?.disconnect()
        manager?.disconnect()
        socket = nil
        manager = nil
    }
    #else
    private func disconnectInternal() { }
    #endif
}