Begin implementing slash commands

Set up a structure not unlike what exists for text commands in order to neatly separate subsets of commands/features into their own files.

Changed references for existing commands to "text commands" where it made sense to do so.

ApplicationCommands/BotApplicationCommand.cs

@@ -0,0 +1,66 @@
+using BirthdayBot.Data;
+using NodaTime;
+using System.Collections.ObjectModel;
+
+namespace BirthdayBot.ApplicationCommands;
+
+/// <summary>
+/// Base class for classes handling slash command execution.
+/// </summary>
+internal abstract class BotApplicationCommand {
+    public delegate Task CommandResponder(ShardInstance instance, GuildConfiguration gconf, SocketSlashCommand arg);
+
+    protected const string ErrGuildOnly = ":x: This command can only be run within a server.";
+    protected string ErrNotAllowed = ":x: Only server moderators may use this command.";
+    protected const string MemberCacheEmptyError = ":warning: Please try the command again.";
+    public const string AccessDeniedError = ":warning: You are not allowed to run this command.";
+
+    protected static ReadOnlyDictionary<string, string> TzNameMap { get; }
+
+    /// <summary>
+    /// Returns a list of application command definitions handled by the implementing class,
+    /// for use when registering/updating this bot's available slash commands.
+    /// </summary>
+    public abstract IEnumerable<ApplicationCommandProperties> GetCommands();
+
+    /// <summary>
+    /// Given the command name, returns the designated handler to execute to fulfill the command.
+    /// Returns null if this class does not contain a handler for the given command.
+    /// </summary>
+    public abstract CommandResponder? GetHandlerFor(string commandName);
+
+    static BotApplicationCommand() {
+        var dict = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        foreach (var name in DateTimeZoneProviders.Tzdb.Ids) dict.Add(name, name);
+        TzNameMap = new(dict);
+    }
+
+    /// <summary>
+    /// Checks given time zone input. Returns a valid string for use with NodaTime,
+    /// throwing a FormatException if the input is not recognized.
+    /// </summary>
+    protected static string ParseTimeZone(string tzinput) {
+        if (!TzNameMap.TryGetValue(tzinput, out string? tz)) throw new FormatException(":x: Unexpected time zone name."
+                     + $" Refer to `INSERT COMMAND NAME HERE` to help determine the correct value."); // TODO fix!!!!!!!!!!!!!!!!!!!
+        return tz!;
+    }
+
+    /// <summary>
+    /// An alternative to <see cref="SocketGuild.HasAllMembers"/> to be called by command handlers needing a full member cache.
+    /// Creates a download request if necessary.
+    /// </summary>
+    /// <returns>
+    /// True if the member cache is already filled, false otherwise.
+    /// </returns>
+    /// <remarks>
+    /// Any updates to the member cache aren't accessible until the event handler finishes execution, meaning proactive downloading
+    /// is necessary, and is handled by <seealso cref="BackgroundServices.AutoUserDownload"/>. In situations where
+    /// this approach fails, this is to be called, and the user must be asked to attempt the command again if this returns false.
+    /// </remarks>
+    protected static async Task<bool> HasMemberCacheAsync(SocketGuild guild) {
+        if (Common.HasMostMembersDownloaded(guild)) return true;
+        // Event handling thread hangs if awaited normally or used with Task.Run
+        await Task.Factory.StartNew(guild.DownloadUsersAsync).ConfigureAwait(false);
+        return false;
+    }
+}

ApplicationCommands/HelpInfoCommands.cs

@@ -0,0 +1,32 @@
+using BirthdayBot.Data;
+
+namespace BirthdayBot.ApplicationCommands;
+
+internal class HelpInfoCommands : BotApplicationCommand {
+    private static readonly ApplicationCommandProperties[] _commands;
+
+    static HelpInfoCommands() {
+        _commands = new ApplicationCommandProperties[] {
+            new SlashCommandBuilder()
+                .WithName("help").WithDescription("attempts to get help").Build(),
+            new SlashCommandBuilder()
+                .WithName("not-help").WithDescription("you're not getting help here").Build()
+        };
+    }
+
+    public override IEnumerable<ApplicationCommandProperties> GetCommands() {
+        return _commands;
+    }
+    public override CommandResponder? GetHandlerFor(string commandName) {
+        switch (commandName) {
+            case "help":
+                return CmdHelp;
+            default:
+                return null;
+        }
+    }
+
+    private async Task CmdHelp(ShardInstance instance, GuildConfiguration gconf, SocketSlashCommand arg) {
+        await arg.RespondAsync("i am help. is this help?");
+    }
+}

ShardInstance.cs

@@ -1,6 +1,8 @@
-using BirthdayBot.BackgroundServices;
+using BirthdayBot.ApplicationCommands;
+using BirthdayBot.BackgroundServices;
 using BirthdayBot.Data;
 using Discord.Net;
+using static BirthdayBot.ApplicationCommands.BotApplicationCommand;
 using static BirthdayBot.TextCommands.CommandsCommon;
 
 namespace BirthdayBot;
@@ -11,7 +13,8 @@ namespace BirthdayBot;
 class ShardInstance : IDisposable {
     private readonly ShardManager _manager;
     private readonly ShardBackgroundWorker _background;
-    private readonly Dictionary<string, CommandHandler> _dispatchCommands;
+    private readonly Dictionary<string, CommandHandler> _textDispatch;
+    private readonly IEnumerable<BotApplicationCommand> _slashCmdHandlers;
 
     public DiscordSocketClient DiscordClient { get; }
     public int ShardId => DiscordClient.ShardId;
@@ -25,17 +28,22 @@ class ShardInstance : IDisposable {
     public string? CurrentExecutingService => _background.CurrentExecutingService;
     public Configuration Config => _manager.Config;
 
+    public const string InternalError = ":x: An unknown error occurred. If it persists, please notify the bot owner.";
+
     /// <summary>
     /// Prepares and configures the shard instances, but does not yet start its connection.
     /// </summary>
-    public ShardInstance(ShardManager manager, DiscordSocketClient client, Dictionary<string, CommandHandler> commands) {
+    public ShardInstance(ShardManager manager, DiscordSocketClient client,
+                         Dictionary<string, CommandHandler> textCmds, IEnumerable<BotApplicationCommand> appCmdHandlers) {
         _manager = manager;
-        _dispatchCommands = commands;
+        _textDispatch = textCmds;
+        _slashCmdHandlers = appCmdHandlers;
 
         DiscordClient = client;
         DiscordClient.Log += Client_Log;
         DiscordClient.Ready += Client_Ready;
         DiscordClient.MessageReceived += Client_MessageReceived;
+        DiscordClient.SlashCommandExecuted += DiscordClient_SlashCommandExecuted;
 
         // Background task constructor begins background processing immediately.
         _background = new ShardBackgroundWorker(this);
@@ -66,7 +74,6 @@ class ShardInstance : IDisposable {
 
     public void Log(string source, string message) => Program.Log($"Shard {ShardId:00}] [{source}", message);
 
-    #region Event handling
     private Task Client_Log(LogMessage arg) {
         // Suppress certain messages
         if (arg.Message != null) {
@@ -94,9 +101,45 @@ class ShardInstance : IDisposable {
     }
 
     /// <summary>
-    /// Sets the shard's status to display the help command.
+    /// Registers all available slash commands.
+    /// Additionally, sets the shard's status to display the help command.
     /// </summary>
-    private async Task Client_Ready() => await DiscordClient.SetGameAsync(CommandPrefix + "help");
+    private async Task Client_Ready() {
+        await DiscordClient.SetGameAsync(CommandPrefix + "help");
+
+#if !DEBUG
+        // Update our commands here, only when the first shard connects
+        if (ShardId != 0) return;
+#endif
+        var commands = new List<ApplicationCommandProperties>();
+        foreach (var source in _slashCmdHandlers) {
+            commands.AddRange(source.GetCommands());
+        }
+#if !DEBUG
+        // Remove any unneeded/unused commands
+        var existingcmdnames = cmds.Select(c => c.Name.Value).ToHashSet();
+        foreach (var gcmd in await DiscordClient.GetGlobalApplicationCommandsAsync()) {
+            if (!existingcmdnames.Contains(gcmd.Name)) {
+                Log("Command registration", $"Found registered unused command /{gcmd.Name} - sending removal request");
+                await gcmd.DeleteAsync();
+            }
+        }
+        // And update what we have
+        Log("Command registration", $"Bulk updating {cmds.Length} global command(s)");
+        await DiscordClient.BulkOverwriteGlobalApplicationCommandsAsync(cmds).ConfigureAwait(false);
+#else
+        // Debug: Register our commands locally instead, in each guild we're in
+        foreach (var g in DiscordClient.Guilds) {
+            await g.DeleteApplicationCommandsAsync().ConfigureAwait(false);
+            await g.BulkOverwriteApplicationCommandAsync(commands.ToArray()).ConfigureAwait(false);
+        }
+
+        foreach (var gcmd in await DiscordClient.GetGlobalApplicationCommandsAsync()) {
+            Program.Log("Command registration", $"Found global command /{gcmd.Name} and we're DEBUG - sending removal request");
+            await gcmd.DeleteAsync();
+        }
+#endif
+    }
 
     /// <summary>
     /// Determines if the incoming message is an incoming command, and dispatches to the appropriate handler if necessary.
@@ -113,7 +156,7 @@ class ShardInstance : IDisposable {
         var csplit = msg.Content.Split(" ", 3, StringSplitOptions.RemoveEmptyEntries);
         if (csplit.Length > 0 && csplit[0].StartsWith(CommandPrefix, StringComparison.OrdinalIgnoreCase)) {
             // Determine if it's something we're listening for.
-            if (!_dispatchCommands.TryGetValue(csplit[0][CommandPrefix.Length..], out CommandHandler? command)) return;
+            if (!_textDispatch.TryGetValue(csplit[0][CommandPrefix.Length..], out CommandHandler? command)) return;
 
             // Load guild information here
             var gconf = await GuildConfiguration.LoadAsync(channel.Guild.Id, false);
@@ -132,10 +175,60 @@ class ShardInstance : IDisposable {
                 if (ex is HttpException) return;
                 Log("Command", ex.ToString());
                 try {
-                    channel.SendMessageAsync(TextCommands.CommandsCommon.InternalError).Wait();
+                    channel.SendMessageAsync(InternalError).Wait();
                 } catch (HttpException) { } // Fail silently
             }
         }
     }
-    #endregion
+
+    /// <summary>
+    /// Dispatches to the appropriate slash command handler while catching any exceptions that may occur.
+    /// </summary>
+    private async Task DiscordClient_SlashCommandExecuted(SocketSlashCommand arg) {
+        SocketGuildChannel? rptChannel = arg.Channel as SocketGuildChannel;
+        var rptId = rptChannel?.Guild.Id ?? arg.User.Id;
+        var logLine = $"/{arg.CommandName} by {arg.User} in { (rptChannel != null ? "guild" : "DM. User") } ID {rptId}. Result: ";
+
+        // Specific reply for DM messages
+        if (rptChannel == null) {
+            // TODO do not hardcode message
+            // TODO figure out appropriate message
+            Log("Command", logLine + "Sending message.");
+            await arg.RespondAsync("don't dm me").ConfigureAwait(false);
+            return;
+        }
+
+        // Determine handler to use
+        CommandResponder? handler = null;
+        foreach (var source in _slashCmdHandlers) {
+            handler = source.GetHandlerFor(arg.CommandName);
+            if (handler != null) break;
+        }
+        
+        if (handler == null) { // Handler not found
+            Log("Command", logLine + "Unknown command.");
+            await arg.RespondAsync("Oops, that command isn't supposed to be there... Please try something else.",
+                ephemeral: true).ConfigureAwait(false);
+            return;
+        }
+
+        var gconf = await GuildConfiguration.LoadAsync(rptChannel.Guild.Id, false);
+        // Block check here
+        if (!gconf!.IsBotModerator((SocketGuildUser)arg.User)) // Except if moderator
+        {
+            if (await gconf.IsUserBlockedAsync(arg.User.Id)) {
+                Log("Command", logLine + "Blocked per guild policy.");
+                await arg.RespondAsync(AccessDeniedError, ephemeral: true).ConfigureAwait(false);
+                return;
+            }
+        }
+
+        // Execute the handler
+        try {
+            await handler(this, gconf, arg).ConfigureAwait(false);
+            Log("Command", logLine + "Executed normally.");
+        } catch (Exception ex) when (ex is not HttpException) {
+            Log("Command", logLine + ex.ToString());
+        }
+    }
 }

ShardManager.cs

@@ -1,5 +1,6 @@
 global using Discord;
 global using Discord.WebSocket;
+using BirthdayBot.ApplicationCommands;
 using BirthdayBot.BackgroundServices;
 using BirthdayBot.TextCommands;
 using System.Text;
@@ -43,11 +44,8 @@ class ShardManager : IDisposable {
     /// </summary>
     private readonly Dictionary<int, ShardInstance?> _shards;
 
-    private readonly Dictionary<string, CommandHandler> _dispatchCommands;
-    private readonly UserCommands _cmdsUser;
-    private readonly ListingCommands _cmdsListing;
-    private readonly HelpInfoCommands _cmdsHelp;
-    private readonly ManagerCommands _cmdsMods;
+    private readonly Dictionary<string, CommandHandler> _textCommands;
+    private readonly List<BotApplicationCommand> _appCommands;
 
     private readonly Task _statusTask;
     private readonly CancellationTokenSource _mainCancel;
@@ -62,15 +60,20 @@ class ShardManager : IDisposable {
         Config = cfg;
 
         // Command handler setup
-        _dispatchCommands = new Dictionary<string, CommandHandler>(StringComparer.OrdinalIgnoreCase);
-        _cmdsUser = new UserCommands(cfg);
-        foreach (var item in _cmdsUser.Commands) _dispatchCommands.Add(item.Item1, item.Item2);
-        _cmdsListing = new ListingCommands(cfg);
-        foreach (var item in _cmdsListing.Commands) _dispatchCommands.Add(item.Item1, item.Item2);
-        _cmdsHelp = new HelpInfoCommands(cfg);
-        foreach (var item in _cmdsHelp.Commands) _dispatchCommands.Add(item.Item1, item.Item2);
-        _cmdsMods = new ManagerCommands(cfg, _cmdsUser.Commands);
-        foreach (var item in _cmdsMods.Commands) _dispatchCommands.Add(item.Item1, item.Item2);
+        _textCommands = new Dictionary<string, CommandHandler>(StringComparer.OrdinalIgnoreCase);
+        var cmdsUser = new UserCommands(cfg);
+        foreach (var item in cmdsUser.Commands) _textCommands.Add(item.Item1, item.Item2);
+        var cmdsListing = new ListingCommands(cfg);
+        foreach (var item in cmdsListing.Commands) _textCommands.Add(item.Item1, item.Item2);
+        var cmdsHelp = new TextCommands.HelpInfoCommands(cfg);
+        foreach (var item in cmdsHelp.Commands) _textCommands.Add(item.Item1, item.Item2);
+        var cmdsMods = new ManagerCommands(cfg, cmdsUser.Commands);
+        foreach (var item in cmdsMods.Commands) _textCommands.Add(item.Item1, item.Item2);
+
+        _appCommands = new List<BotApplicationCommand>() {
+            // TODO fill this out
+            new ApplicationCommands.HelpInfoCommands()
+        };
 
         // Allocate shards based on configuration
         _shards = new Dictionary<int, ShardInstance?>();
@@ -119,7 +122,7 @@ class ShardManager : IDisposable {
             GatewayIntents = GatewayIntents.Guilds | GatewayIntents.GuildMembers | GatewayIntents.GuildMessages
         };
         var newClient = new DiscordSocketClient(clientConf);
-        newInstance = new ShardInstance(this, newClient, _dispatchCommands);
+        newInstance = new ShardInstance(this, newClient, _textCommands, _appCommands);
         await newInstance.StartAsync().ConfigureAwait(false);
 
         return newInstance;

TextCommands/CommandsCommon.cs

@@ -17,7 +17,6 @@ internal abstract class CommandsCommon {
     public const string BadUserError = ":x: Unable to find user. Specify their `@` mention or their ID.";
     public const string ParameterError = ":x: Invalid usage. Refer to how to use the command and try again.";
     public const string NoParameterError = ":x: This command does not accept any parameters.";
-    public const string InternalError = ":x: An unknown error occurred. If it persists, please notify the bot owner.";
     public const string MemberCacheEmptyError = ":warning: Please try the command again.";
 
     public delegate Task CommandHandler(ShardInstance instance, GuildConfiguration gconf,
@@ -48,7 +47,6 @@ internal abstract class CommandsCommon {
     /// Checks given time zone input. Returns a valid string for use with NodaTime.
     /// </summary>
     protected static string ParseTimeZone(string tzinput) {
-        if (tzinput.Equals("Asia/Calcutta", StringComparison.OrdinalIgnoreCase)) tzinput = "Asia/Kolkata";
         if (!TzNameMap.TryGetValue(tzinput, out string? tz)) throw new FormatException(":x: Unexpected time zone name."
                      + $" Refer to `{CommandPrefix}help-tzdata` to help determine the correct value.");
         return tz;

TextCommands/ListingCommands.cs

@@ -128,7 +128,7 @@ internal class ListingCommands : CommandsCommon {
             reqChannel.SendMessageAsync(":x: Unable to send list due to a permissions issue. Check the 'Attach Files' permission.").Wait();
         } catch (Exception ex) {
             Program.Log("Listing", ex.ToString());
-            reqChannel.SendMessageAsync(InternalError).Wait();
+            reqChannel.SendMessageAsync(ShardInstance.InternalError).Wait();
         } finally {
             File.Delete(filepath);
         }

TextCommands/UserCommands.cs

@@ -120,7 +120,7 @@ internal class UserCommands : CommandsCommon {
             await user.UpdateAsync(bmonth, bday, user.TimeZone).ConfigureAwait(false);
         } catch (Exception ex) {
             Program.Log("Error", ex.ToString());
-            reqChannel.SendMessageAsync(InternalError).Wait();
+            reqChannel.SendMessageAsync(ShardInstance.InternalError).Wait();
             return;
         }
         await reqChannel.SendMessageAsync($":white_check_mark: Your birthday has been { (known ? "updated" : "recorded") }.")