sharp-chat/SharpChat/ChatContext.cs

using SharpChat.Events;
using SharpChat.Flashii;
using SharpChat.Packet;
using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Http;
using System.Threading;

namespace SharpChat {
    public class ChatContext : IDisposable, IPacketTarget {
        public bool IsDisposed { get; private set; }

        private readonly HttpClient HttpClient;

        public SockChatServer Server { get; }
        public Timer BumpTimer { get; }

        public BanManager Bans { get; }
        public readonly object BansAccess = new();

        public ChannelManager Channels { get; }
        public UserManager Users { get; }
        public ChatEventManager Events { get; }

        public string TargetName => @"@broadcast";

        public ChatContext(HttpClient httpClient, SockChatServer server) {
            HttpClient = httpClient;
            Server = server;
            Bans = new(httpClient, this);
            Users = new(this);
            Channels = new(this);
            Events = new(this);

            BumpTimer = new Timer(e => FlashiiBump.SubmitAsync(HttpClient, Users.WithActiveConnections()).Wait(), null, TimeSpan.Zero, TimeSpan.FromMinutes(1));
        }

        public void Update() {
            lock(BansAccess)
                Bans.RemoveExpired();
            CheckPings();
        }

        public void BanUser(ChatUser user, DateTimeOffset? until = null, bool banIPs = false, UserDisconnectReason reason = UserDisconnectReason.Kicked) {
            if(until.HasValue && until.Value <= DateTimeOffset.UtcNow)
                until = null;

            if(until.HasValue) {
                user.Send(new ForceDisconnectPacket(ForceDisconnectReason.Banned, until.Value));

                lock(BansAccess) {
                    Bans.Add(user, until.Value);

                    if(banIPs)
                        foreach(IPAddress ip in user.RemoteAddresses)
                            Bans.Add(ip, until.Value);
                }
            } else
                user.Send(new ForceDisconnectPacket(ForceDisconnectReason.Kicked));

            user.Close();
            UserLeave(user.Channel, user, reason);
        }

        public void HandleJoin(ChatUser user, ChatChannel chan, ChatUserSession sess) {
            if(!chan.HasUser(user)) {
                chan.Send(new UserConnectPacket(DateTimeOffset.Now, user));
                Events.Add(new UserConnectEvent(DateTimeOffset.Now, user, chan));
            }

            sess.Send(new AuthSuccessPacket(user, chan, sess));
            sess.Send(new ContextUsersPacket(chan.GetUsers(new[] { user })));

            IEnumerable<IChatEvent> msgs = Events.GetTargetLog(chan);

            foreach(IChatEvent msg in msgs)
                sess.Send(new ContextMessagePacket(msg));

            sess.Send(new ContextChannelsPacket(Channels.OfHierarchy(user.Rank)));

            if(!chan.HasUser(user))
                chan.UserJoin(user);

            if(!Users.Contains(user))
                Users.Add(user);
        }

        public void UserLeave(ChatChannel chan, ChatUser user, UserDisconnectReason reason = UserDisconnectReason.Leave) {
            user.Status = ChatUserStatus.Offline;

            if(chan == null) {
                foreach(ChatChannel channel in user.GetChannels()) {
                    UserLeave(channel, user, reason);
                }
                return;
            }

            if(chan.IsTemporary && chan.Owner == user)
                Channels.Remove(chan);

            chan.UserLeave(user);
            chan.Send(new UserDisconnectPacket(DateTimeOffset.Now, user, reason));
            Events.Add(new UserDisconnectEvent(DateTimeOffset.Now, user, chan, reason));
        }

        public void SwitchChannel(ChatUser user, ChatChannel chan, string password) {
            if(user.CurrentChannel == chan) {
                //user.Send(true, @"samechan", chan.Name);
                user.ForceChannel();
                return;
            }

            if(!user.Can(ChatUserPermissions.JoinAnyChannel) && chan.Owner != user) {
                if(chan.Rank > user.Rank) {
                    user.Send(new LegacyCommandResponse(LCR.CHANNEL_INSUFFICIENT_HIERARCHY, true, chan.Name));
                    user.ForceChannel();
                    return;
                }

                if(chan.Password != password) {
                    user.Send(new LegacyCommandResponse(LCR.CHANNEL_INVALID_PASSWORD, true, chan.Name));
                    user.ForceChannel();
                    return;
                }
            }

            ForceChannelSwitch(user, chan);
        }

        public void ForceChannelSwitch(ChatUser user, ChatChannel chan) {
            if(!Channels.Contains(chan))
                return;

            ChatChannel oldChan = user.CurrentChannel;

            oldChan.Send(new UserChannelLeavePacket(user));
            Events.Add(new UserChannelLeaveEvent(DateTimeOffset.Now, user, oldChan));
            chan.Send(new UserChannelJoinPacket(user));
            Events.Add(new UserChannelJoinEvent(DateTimeOffset.Now, user, chan));

            user.Send(new ContextClearPacket(chan, ContextClearMode.MessagesUsers));
            user.Send(new ContextUsersPacket(chan.GetUsers(new[] { user })));

            IEnumerable<IChatEvent> msgs = Events.GetTargetLog(chan);

            foreach(IChatEvent msg in msgs)
                user.Send(new ContextMessagePacket(msg));

            user.ForceChannel(chan);
            oldChan.UserLeave(user);
            chan.UserJoin(user);

            if(oldChan.IsTemporary && oldChan.Owner == user)
                Channels.Remove(oldChan);
        }

        public void CheckPings() {
            lock(Users)
                foreach(ChatUser user in Users.All()) {
                    IEnumerable<ChatUserSession> timedOut = user.GetDeadSessions();

                    foreach(ChatUserSession sess in timedOut) {
                        user.RemoveSession(sess);
                        sess.Dispose();
                        Logger.Write($@"Nuked session {sess.Id} from {user.Username} (timeout)");
                    }

                    if(!user.HasSessions)
                        UserLeave(null, user, UserDisconnectReason.TimeOut);
                }
        }

        public void Send(IServerPacket packet) {
            foreach(ChatUser user in Users.All())
                user.Send(packet);
        }

        ~ChatContext() {
            DoDispose();
        }

        public void Dispose() {
            DoDispose();
            GC.SuppressFinalize(this);
        }

        private void DoDispose() {
            if(IsDisposed)
                return;
            IsDisposed = true;

            BumpTimer?.Dispose();
            Events?.Dispose();
            Channels?.Dispose();
            Users?.Dispose();
            Bans?.Dispose();
        }
    }
}