sharp-chat/SharpChat.Protocol.SockChat/Commands/WhoCommand.cs

using SharpChat.Channels;
using SharpChat.Protocol.SockChat.Packets;
using SharpChat.Users;
using System;
using System.Collections.Generic;
using System.Linq;

namespace SharpChat.Protocol.SockChat.Commands {
    public class WhoCommand : ICommand {
        private UserManager Users { get; }
        private ChannelManager Channels { get; }
        private ChannelUserRelations ChannelUsers { get; }
        private IUser Sender { get; }

        public WhoCommand(UserManager users, ChannelManager channels, ChannelUserRelations channelUsers, IUser sender) {
            Users = users ?? throw new ArgumentNullException(nameof(users));
            Channels = channels ?? throw new ArgumentNullException(nameof(channels));
            ChannelUsers = channelUsers ?? throw new ArgumentNullException(nameof(channelUsers));
            Sender = sender ?? throw new ArgumentNullException(nameof(sender));
        }

        public bool IsCommandMatch(string name, IEnumerable<string> args)
            => name == @"who";

        private void WhoServer(CommandContext ctx) {
            Users.GetUsers(u => {
                ctx.Connection.SendPacket(new UserListResponsePacket(Sender, ctx.User, u));
            });
        }

        private void WhoChannel(CommandContext ctx, string channelName) {
            Channels.GetChannelByName(channelName, channel => {
                if(channel == null) {
                    ctx.Connection.SendPacket(new ChannelNotFoundErrorPacket(Sender, channelName));
                    return;
                }

                if(channel.MinimumRank > ctx.User.Rank || (channel.HasPassword && !ctx.User.Can(UserPermissions.JoinAnyChannel))) {
                    ctx.Connection.SendPacket(new UserListChannelNotFoundPacket(Sender, channelName));
                    return;
                }

                ChannelUsers.GetUsers(
                    channel,
                    users => ctx.Connection.SendPacket(new UserListResponsePacket(
                        Sender,
                        channel,
                        ctx.User,
                        users.OrderByDescending(u => u.Rank)
                    ))
                );
            });
        }

        public bool DispatchCommand(CommandContext ctx) {
            string channelName = ctx.Args.ElementAtOrDefault(1) ?? string.Empty;

            if(string.IsNullOrEmpty(channelName))
                WhoServer(ctx);
            else
                WhoChannel(ctx, channelName);

            return true;
        }
    }
}