using LobbyServerDto;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Security.Cryptography;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Lobbies
{
    public class LobbyClient : IDisposable
    {
        TcpLobbbyClient tcpClient = new TcpLobbbyClient();
        private readonly ConcurrentQueue<LobbyClientEvent> events = new ConcurrentQueue<LobbyClientEvent>();
        BufferRental bufferRental = new BufferRental(4096);
        public void Connect(string host, int port, CancellationToken cancellationToken)
        {
            try
            {
                cancellationToken.ThrowIfCancellationRequested();
                using var cts = cancellationToken.Register(() =>
                {
                    tcpClient.Stop();                    
                });

                tcpClient.DataReceived -= TcpClient_DataReceived;
                tcpClient.DataReceived += TcpClient_DataReceived;

                tcpClient.Disconnected -= TcpClient_Disconnected;
                tcpClient.Disconnected += TcpClient_Disconnected;

                tcpClient.Connected -= TcpClient_Connected;
                tcpClient.Connected += TcpClient_Connected;

                _ = Task.Run(() => tcpClient.Connect(host, port));
            }
            catch
            {

            }            
        }

        public IEnumerable<LobbyClientEvent> ReadEvents(int maxEvents)
        {
            if (events.Count > 0)
            {
                maxEvents = Math.Min(maxEvents, events.Count);

                while (maxEvents > 0) 
                {
                    if(events.TryDequeue(out var _event))
                    {
                        yield return _event;
                    } 
                    else
                    {
                        break;
                    }
                }
            }
        }

        public void HostLobby(Guid gameId, string name, int gameMode, int maxPlayerCount,string? password, string? ip, int port)
        {
            var lobbyCreate = new LobbyCreate() 
            { 
                GameId = gameId,
                Name = name,
                GameMode = gameMode,
                MaxPlayerCount = maxPlayerCount,
                PlayerCount = 0,
                PasswordHash = string.IsNullOrEmpty(password) ? null : SHA256.HashData(Encoding.UTF8.GetBytes(password)),
                HostIp = ip,
                HostPort = port
            };

            byte[] messageData = bufferRental.Rent();
            var len = lobbyCreate.Serialize(messageData);            
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void RequestLobbyHostInfo(Guid lobbyId, string? password)
        {
            var lobbyCreate = new LobbyRequestHostInfo()
            {
                LobbyId = lobbyId,
                PasswordHash = string.IsNullOrEmpty(password) ? null : SHA256.HashData(Encoding.UTF8.GetBytes(password)),
            };

            byte[] messageData = bufferRental.Rent();
            var len = lobbyCreate.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void RequestLobbyNatPunch(Guid lobbyId, string? password, string? clientIp, int clientPort)
        {
            var lobbyRequestNatPunch = new LobbyRequestNatPunch()
            {
                LobbyId = lobbyId,
                PasswordHash = string.IsNullOrEmpty(password) ? null : SHA256.HashData(Encoding.UTF8.GetBytes(password)),
                ClientIp = clientIp,
                ClientPort = clientPort
            };

            byte[] messageData = bufferRental.Rent();
            var len = lobbyRequestNatPunch.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void UpdateLobby(string name, int gameMode, int maxPlayerCount, int playerCount, string? password, string? ip, int port)
        {
            var lobbyUpdate = new LobbyUpdate()
            {
                Name = name,
                GameMode = gameMode,
                MaxPlayerCount = maxPlayerCount,
                PlayerCount = playerCount,
                PasswordHash = string.IsNullOrEmpty(password) ? null : SHA256.HashData(Encoding.UTF8.GetBytes(password)),
                HostIp = ip,
                HostPort = port
            };

            byte[] messageData = bufferRental.Rent();
            var len = lobbyUpdate.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void CloseLobby()
        {
            var lobbyDelete = new LobbyDelete()
            {

            };

            byte[] messageData = bufferRental.Rent();
            var len = lobbyDelete.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void ObserveLobbies(Guid gameId)
        {
            var lobbiesObserve = new LobbiesObserve() { GameId = gameId };

            byte[] messageData = bufferRental.Rent();
            var len = lobbiesObserve.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void StopObservingLobbies()
        {
            var lobbiesStopObserve = new LobbiesStopObserve() { };

            byte[] messageData = bufferRental.Rent();
            var len = lobbiesStopObserve.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void NotifyLobbyNatPunchDone(int natPunchId)
        {
            var lobbyNatPunchDone = new LobbyNatPunchDone() { NatPunchId = natPunchId };

            byte[] messageData = bufferRental.Rent();
            var len = lobbyNatPunchDone.Serialize(messageData);
            _ = Task.Run(async () => { await tcpClient.Send(messageData, 0, len); bufferRental.Return(messageData); });
        }

        public void Stop()
        {
            tcpClient.Stop();
        }

        private void TcpClient_Connected()
        {
            events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.Connected, EventData = null });
        }

        private void TcpClient_Disconnected(bool clean, string error)
        {
            if(!clean)
                events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.Failed, EventData = new LobbyClientDisconnectReason { WasError = true, ErrorMessage = error } });
            else
                events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.Disconnected, EventData = new LobbyClientDisconnectReason { WasError = false, ErrorMessage = string.Empty } });
        }

        private int PeekTypeId(ReadOnlySpan<byte> buffer)
        {
            int typeId = 0;
            int shift = 0;
            int offset = 0;
            byte b;
            do
            {
                {
                    // Check for a corrupted stream.  Read a max of 5 bytes.
                    // In a future version, add a DataFormatException.
                    if (shift == 5 * 7)  // 5 bytes max per Int32, shift += 7
                        throw new FormatException("Format_Bad7BitInt32");

                    // ReadByte handles end of stream cases for us.
                    b = buffer[offset++];
                    typeId |= (b & 0x7F) << shift;
                    shift += 7;
                }
            } while ((b & 0x80) != 0);

            return typeId;
        }

        private void TcpClient_DataReceived(int dataLength, Memory<byte> data)
        {
            try
            {
                if (dataLength > 0)
                {
                    switch (PeekTypeId(data.Span))
                    {
                        case LobbyInfo.TypeId:
                            {
                                var lobbyInfo = LobbyInfo.Deserialize(data.Span);
                                if (lobbyInfo != null)
                                {
                                    events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.LobbyUpdate, EventData = lobbyInfo });
                                }
                            }
                            break;
                        case LobbyDelete.TypeId:
                            {
                                var lobbyDelete = LobbyDelete.Deserialize(data.Span);
                                if (lobbyDelete != null)
                                {
                                    events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.LobbyDelete, EventData = lobbyDelete });
                                }
                            }
                            break;
                        case LobbyHostInfo.TypeId:
                            {
                                var lobbyHostInfo = LobbyHostInfo.Deserialize(data.Span);
                                if (lobbyHostInfo != null)
                                {
                                    events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.LobbyHostInfo, EventData = lobbyHostInfo });
                                }
                            }
                            break;
                        case LobbyRequestNatPunch.TypeId:
                            {
                                var lobbyRequestNatPunch = LobbyRequestNatPunch.Deserialize(data.Span);
                                if (lobbyRequestNatPunch != null)
                                {
                                    events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.LobbyRequestNatPunch, EventData = lobbyRequestNatPunch });
                                }
                            }
                            break;
                        case LobbyNatPunchDone.TypeId:
                            {
                                var lobbyNatPunchDone = LobbyNatPunchDone.Deserialize(data.Span);
                                if (lobbyNatPunchDone != null)
                                {
                                    events.Enqueue(new LobbyClientEvent { EventType = LobbyClientEventTypes.LobbyNatPunchDone, EventData = lobbyNatPunchDone });
                                }
                            }
                            break;
                    }
                }
            }
            catch { }
        }

        public void Dispose()
        {
           tcpClient.Dispose();
        }

    }
}