//
//  NetworkServiceApiWebSockets.swift
//  Wallet
//
//  Created by Saveliy Stavitsky on 1/15/21.
//  Copyright © 2021 AM. All rights reserved.
//

import Foundation
import Starscream

extension Notification.Name {
    static let socketDidConnect = Self("Network.Service.WebSockets.socketDidConnect")
    static let socketDidUpdateValue = Self("Network.Service.WebSockets.socketDidUpdateValue")
    static let socketDidDisconnect = Self("Network.Service.WebSockets.socketDidDisconnect")
}

extension Network.Service {
    
    final class WebSockets: Common.Service.Provider {
        
        private var timer: Timer?
        private var reconectTimer: Timer?
        private var collection = [String: Subscription]()
        
        init() {
            self.timer = delayed(45, repeats: true) { self.update() }
            self.reconectTimer = delayed(1, repeats: true) { self.reconect() }
        }
    }
}

extension Network.Service.WebSockets {
    
    func open(subscription: String, id: String) {
        self.collection[id] = Subscription(id: id, subscription: subscription)
    }
    
    func contains(id: String) -> Bool {
        self.collection[id].isExist
    }
    
    func remove(id: String) {
        self.collection[id] = nil
    }
    
    func remove(idPrefix prefix: String) {
        self.collection
            .filter { $0.key.hasPrefix(prefix) }
            .map { $0.key }
            .forEach { self.collection[$0] = nil }
    }
    
    func remove(idSuffix suffix: String) {
        self.collection
            .filter { $0.key.hasSuffix(suffix) }
            .map { $0.key }
            .forEach { self.collection[$0] = nil }
    }
    
    func removeAll() {
        self.collection = [:]
    }
}

extension Network.Service.WebSockets {
    
    private func update() {
        
        self.collection.forEach { subscription in
            if !subscription.value.socket.isConnected {
                subscription.value.socket.connect()
            } else {
                subscription.value.socket.write(ping: Data())
            }
        }
    }
    private func reconect() {
        
        self.collection
            .filter { !$0.value.socket.isConnected }
            .forEach { $0.value.socket.connect() }
    }
}

extension Network.Service.WebSockets {
    
    fileprivate final class Subscription {
        
        let socket: WebSocket
        let id: String
        let subscription: String?
        
        init(id: String, subscription: String?) {
            self.id = id
            self.subscription = subscription
            
            let environment = ApplicationEnvironment.shared().current
            var request = URLRequest(url: URL(string: environment.backend.webSocket)!)
            request.timeoutInterval = 5
            environment.headers.forEach { (key, value) in
                request.addValue(value, forHTTPHeaderField: key)
            }
            
            self.socket = WebSocket(request: request)
            self.socket.advancedDelegate = self
            self.socket.connect()
        }
        
        deinit { self.socket.disconnect() }
        
    }
}

extension Network.Service.WebSockets.Subscription: WebSocketAdvancedDelegate {
    
    func websocketDidConnect(socket: WebSocket) {
        // print("websocketDidConnect")
        if let subscription = self.subscription {
            socket.write(string: subscription)
        }
        Notification.post(name: .socketDidConnect, userInfo: ["id": self.id])
    }
    
    func websocketDidDisconnect(socket: WebSocket, error: Error?) {
        // print("websocketDidDisconnect: \(error)")
        // socket.connect() // do not reconnect continuously
        Notification.post(name: .socketDidDisconnect, userInfo: ["id": self.id])
    }
    
    func websocketDidReceiveMessage(socket: WebSocket, text: String, response: WebSocket.WSResponse) {
        Notification.post(name: .socketDidUpdateValue, userInfo: ["id": self.id, "data": text])
    }
    
    func websocketDidReceiveData(socket: WebSocket, data: Data, response: WebSocket.WSResponse) {
        // print("websocketDidReceiveData: \(response.code)")
        Notification.post(name: .socketDidUpdateValue, userInfo: ["id": self.id,
                                                                  "data": String(data: data, encoding: .utf8) ?? ""])
    }
    
    func websocketHttpUpgrade(socket: WebSocket, request: String) {
        // print("websocketHttpUpgrade: \(request)")
    }
    
    func websocketHttpUpgrade(socket: WebSocket, response: String) {
        // print("websocketHttpUpgrade: \(response)")
    }
}