sharp-chat/SharpChat/Packet/ContextMessagePacket.cs

using SharpChat.Events;
using System;
using System.Collections.Generic;
using System.Text;

namespace SharpChat.Packet {
    public class ContextMessagePacket : ServerPacket {
        public IChatEvent Event { get; private set; }
        public bool Notify { get; private set; }

        public ContextMessagePacket(IChatEvent evt, bool notify = false) {
            Event = evt ?? throw new ArgumentNullException(nameof(evt));
            Notify = notify;
        }

        private const string V1_CHATBOT = "-1\tChatBot\tinherit\t\t";

        public override IEnumerable<string> Pack() {
            StringBuilder sb = new();

            sb.Append('7');
            sb.Append('\t');
            sb.Append('1');
            sb.Append('\t');
            sb.Append(Event.DateTime.ToUnixTimeSeconds());
            sb.Append('\t');

            switch(Event) {
                case IChatMessage msg:
                    sb.Append(Event.Sender.Pack());
                    sb.Append('\t');
                    sb.Append(
                        msg.Text
                            .Replace("<", "&lt;")
                            .Replace(">", "&gt;")
                            .Replace("\n", " <br/> ")
                            .Replace("\t", "    ")
                    );
                    break;

                case UserConnectEvent _:
                    sb.Append(V1_CHATBOT);
                    sb.Append("0\fjoin\f");
                    sb.Append(Event.Sender.Username);
                    break;

                case UserChannelJoinEvent _:
                    sb.Append(V1_CHATBOT);
                    sb.Append("0\fjchan\f");
                    sb.Append(Event.Sender.Username);
                    break;

                case UserChannelLeaveEvent _:
                    sb.Append(V1_CHATBOT);
                    sb.Append("0\flchan\f");
                    sb.Append(Event.Sender.Username);
                    break;

                case UserDisconnectEvent ude:
                    sb.Append(V1_CHATBOT);
                    sb.Append("0\f");

                    switch(ude.Reason) {
                        case UserDisconnectReason.Flood:
                            sb.Append("flood");
                            break;
                        case UserDisconnectReason.Kicked:
                            sb.Append("kick");
                            break;
                        case UserDisconnectReason.TimeOut:
                            sb.Append("timeout");
                            break;
                        case UserDisconnectReason.Leave:
                        default:
                            sb.Append("leave");
                            break;
                    }

                    sb.Append('\f');
                    sb.Append(Event.Sender.Username);
                    break;
            }


            sb.Append('\t');
            sb.Append(Event.SequenceId < 1 ? SequenceId : Event.SequenceId);
            sb.Append('\t');
            sb.Append(Notify ? '1' : '0');
            sb.AppendFormat(
                "\t1{0}0{1}{2}",
                Event.Flags.HasFlag(ChatMessageFlags.Action) ? '1' : '0',
                Event.Flags.HasFlag(ChatMessageFlags.Action) ? '0' : '1',
                Event.Flags.HasFlag(ChatMessageFlags.Private) ? '1' : '0'
            );

            yield return sb.ToString();
        }
    }
}