using SignalRClient.Contracts;

using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;

using Microsoft.AspNet.SignalR.Client;

namespace SignalRClient
{
    [ClassInterface(ClassInterfaceType.None)]
    [ComSourceInterfaces(typeof(IExchangeEvents))]
    [Guid("3FBA514A-326B-4F34-BFF4-425AF4115B43")]
    [ProgId("SignalRClient.ExchangeHub")]
    public class ExchangeHub : IExchangeClient
    {
        public const string HUB_DIR = ".\\SignalRClient";
        public const string HUB_NAME = nameof(IExchangeHub);

        public event DoubleEventHandler ExchangeQ;
        public event DoubleEventHandler ExchangeV;

        private readonly ICollection<IDisposable> disposables;

        private HubConnection connection;
        private IHubProxy proxy;

        public ExchangeHub()
        {
            Directory.CreateDirectory(HUB_DIR);

            this.disposables = new List<IDisposable>();
        }

        public bool Connected { get; private set; }

        public bool Connect(string url)
        {
            this.connection = new HubConnection(url);
            this.connection.Closed += this.Connection_Closed;
            this.connection.ConnectionSlow += Connection_ConnectionSlow;
            this.connection.Error += this.Connection_Error;
            this.connection.Received += this.Connection_Received;
            this.connection.Reconnected += this.Connection_Reconnected;
            this.connection.Reconnecting += this.Connection_Reconnecting;
            this.connection.StateChanged += this.Connection_StateChanged;

            this.proxy = this.connection.CreateHubProxy(HUB_NAME);
            var disposableQ = this.proxy.On<double>(nameof(this.SendExchangeQ), x => this.ExchangeQ?.Invoke(x));
            var disposableV = this.proxy.On<double>(nameof(this.SendExchangeV), x => this.ExchangeV?.Invoke(x));

            this.disposables.Add(disposableQ);
            this.disposables.Add(disposableV);

            try
            {
                this.connection
                    .Start()
                    .Wait();
            }
            catch (Exception e)
            {
                this.FileAppendLine(e.ToString());
            }

            return this.connection.State == ConnectionState.Connected;
        }

        public void Dispose()
        {
            foreach (var disposable in this.disposables)
            {
                disposable?.Dispose();
            }

            this.connection.Stop();
        }

        public void SendExchangeQ(double value)
            => this.proxy.Invoke(nameof(this.SendExchangeQ), new object[] { value });

        public void SendExchangeV(Double value)
            => this.proxy.Invoke(nameof(this.SendExchangeV), new object[] { value });

        private void Connection_Closed()
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine("HubConnection closed!");
        }

        private void Connection_ConnectionSlow()
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine("HubConnection is about to timeout!");
        }

        private void Connection_Error(Exception e)
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine(e.ToString());
        }

        private void Connection_Received(string data)
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine(data);
        }

        private void Connection_Reconnected()
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine("HubConnection reconnected!");
        }

        private void Connection_Reconnecting()
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine("HubConnection reconnecting!");
        }

        private void Connection_StateChanged(StateChange state)
        {
            this.Connected = this.connection.State == ConnectionState.Connected;

            this.FileAppendLine($"{state.OldState} -> {state.NewState}");
        }

        private void FileAppendLine(string text)
            => File.AppendAllText($"{HUB_DIR}\\{DateTime.Now:yyyy_MM_dd}.txt", $"[{DateTime.Now:HH:mm:ss}] {text}{Environment.NewLine}");
    }
}