using AspShogiSockets.Extensions;
using AspShogiSockets.Managers.Utility;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Net.WebSockets;
using System.Threading.Tasks;
using Websockets.Managers.ClientActionHandlers;
using Websockets.ServiceModels.Types;

namespace Websockets.Managers
{
  public interface ISocketCommunicationManager
  {
    Task CommunicateWith(WebSocket w, string s);
    Task BroadcastToAll(string msg);
    Task BroadcastToGame(string gameName, Func<string, WebSocket, string> msgBuilder);
    Task BroadcastToGame(string gameName, string msg);
    void SubscribeToGame(WebSocket socket, string gameName, string playerName);
    void SubscribeToBroadcast(WebSocket socket, string playerName);
    void UnsubscribeFromBroadcastAndGames(string playerName);
    void UnsubscribeFromGame(string gameName, string playerName);
  }

  public class SocketCommunicationManager : ISocketCommunicationManager
  {
    private readonly ConcurrentDictionary<string, WebSocket> connections;
    private readonly ConcurrentDictionary<string, List<string>> gameSeats;
    private readonly ILogger<SocketCommunicationManager> logger;
    private readonly ActionHandlerResolver handlerResolver;

    public SocketCommunicationManager(
      ILogger<SocketCommunicationManager> logger,
      ActionHandlerResolver handlerResolver)
    {
      this.logger = logger;
      this.handlerResolver = handlerResolver;
      connections = new ConcurrentDictionary<string, WebSocket>();
      gameSeats = new ConcurrentDictionary<string, List<string>>();
    }

    public async Task CommunicateWith(WebSocket socket, string userName)
    {
      SubscribeToBroadcast(socket, userName);

      while (!socket.CloseStatus.HasValue)
      {
        try
        {
          var message = await socket.ReceiveTextAsync();
          if (string.IsNullOrWhiteSpace(message)) continue;

          var request = JsonConvert.DeserializeObject<Request>(message);
          if (!Enum.IsDefined(typeof(ClientAction), request.Action))
          {
            await socket.SendTextAsync("Error: Action not recognized.");
          }
          else
          {
            var handler = handlerResolver(request.Action);
            await handler.Handle(socket, message, userName);
          }
        }
        catch (OperationCanceledException ex)
        {
          logger.LogError(ex.Message);
        }
      }
      UnsubscribeFromBroadcastAndGames(userName);
    }

    public void SubscribeToBroadcast(WebSocket socket, string playerName)
    {
      logger.LogInformation("Subscribing [{0}] to broadcast", playerName);
      connections.TryAdd(playerName, socket);
    }

    public void UnsubscribeFromBroadcastAndGames(string playerName)
    {
      logger.LogInformation("Unsubscribing [{0}] from broadcast", playerName);
      connections.TryRemove(playerName, out _);
      foreach (var game in gameSeats)
      {
        game.Value.Remove(playerName);
      }
    }

    /// <summary>
    /// Unsubscribes the player from their current game, then subscribes to the new game.
    /// </summary>
    public void SubscribeToGame(WebSocket socket, string gameName, string playerName)
    {
      // Unsubscribe from any other games
      foreach (var kvp in gameSeats)
      {
        var gameNameKey = kvp.Key;
        UnsubscribeFromGame(gameNameKey, playerName);
      }

      // Subscribe
      logger.LogInformation("Subscribing player [{0}] to game [{1}]", playerName, gameName);
      var addSuccess = gameSeats.TryAdd(gameName, new List<string> { playerName });
      if (!addSuccess && !gameSeats[gameName].Contains(playerName))
      {
        gameSeats[gameName].Add(playerName);
      }
    }

    public void UnsubscribeFromGame(string gameName, string playerName)
    {
      if (gameSeats.ContainsKey(gameName))
      {
        logger.LogInformation("Unsubscribing player [{0}] from game [{1}]", playerName, gameName);
        gameSeats[gameName].Remove(playerName);
        if (gameSeats[gameName].Count == 0) gameSeats.TryRemove(gameName, out _);
      }
    }

    public async Task BroadcastToAll(string msg)
    {
      var tasks = connections.Select(kvp =>
      {
        var player = kvp.Key;
        var socket = kvp.Value;
        logger.LogInformation("Broadcasting to player [{0}] \n{1}\n", new[] { player, msg });
        return socket.SendTextAsync(msg);
      });
      await Task.WhenAll(tasks);
    }

    public async Task BroadcastToGame(string gameName, string msg)
    {
      if (gameSeats.ContainsKey(gameName))
      {
        var tasks = gameSeats[gameName]
            .Select(playerName =>
            {
              logger.LogInformation("Broadcasting to game [{0}], player [{0}] \n{1}\n", gameName, playerName, msg);
              return connections[playerName];
            })
            .Where(stream => stream != null)
            .Select(socket => socket.SendTextAsync(msg));
        await Task.WhenAll(tasks);
      }
    }

    public async Task BroadcastToGame(string gameName, Func<string, WebSocket, string> msgBuilder)
    {
      if (gameSeats.ContainsKey(gameName))
      {
        var tasks = gameSeats[gameName]
            .Select(playerName =>
            {
              var socket = connections[playerName];
              var msg = msgBuilder(playerName, socket);
              logger.LogInformation("Broadcasting to game [{0}], player [{0}] \n{1}\n", gameName, playerName, msg);
              return socket.SendTextAsync(msg);
            });
        await Task.WhenAll(tasks);
      }
    }
  }
}