Apply official naming guidelines to Octobot (#306)

1. The root namespace was changed from `Octobot` to
`TeamOctolings.Octobot`:
> DO prefix namespace names with a company name to prevent namespaces
from different companies from having the same name.
2. `Octobot.cs` was renamed to `Program.cs`:
> DO NOT use the same name for a namespace and a type in that namespace.
3. `IOption`, `Option` were renamed to `IGuildOption` and `GuildOption`
respectively:
> DO NOT introduce generic type names such as Element, Node, Log, and
Message.
4. `Utility` was moved out of the `Services` namespace. It didn't belong
there anyway
5. `Program` static fields were moved to `Utility`
6. Localisation files were moved back to the project source files. Looks
like this fixed `Message.Designer.cs` code generation

---------

Signed-off-by: Octol1ttle <l1ttleofficial@outlook.com>

TeamOctolings.Octobot/Commands/ClearCommandGroup.cs

@@ -0,0 +1,169 @@
+using System.ComponentModel;
+using System.Text;
+using JetBrains.Annotations;
+using Remora.Commands.Attributes;
+using Remora.Commands.Groups;
+using Remora.Discord.API.Abstractions.Objects;
+using Remora.Discord.API.Abstractions.Rest;
+using Remora.Discord.Commands.Attributes;
+using Remora.Discord.Commands.Conditions;
+using Remora.Discord.Commands.Contexts;
+using Remora.Discord.Commands.Feedback.Services;
+using Remora.Discord.Extensions.Embeds;
+using Remora.Discord.Extensions.Formatting;
+using Remora.Rest.Core;
+using Remora.Results;
+using TeamOctolings.Octobot.Data;
+using TeamOctolings.Octobot.Extensions;
+using TeamOctolings.Octobot.Services;
+
+namespace TeamOctolings.Octobot.Commands;
+
+/// <summary>
+///     Handles the command to clear messages in a channel: /clear.
+/// </summary>
+[UsedImplicitly]
+public class ClearCommandGroup : CommandGroup
+{
+    private readonly IDiscordRestChannelAPI _channelApi;
+    private readonly ICommandContext _context;
+    private readonly IFeedbackService _feedback;
+    private readonly GuildDataService _guildData;
+    private readonly IDiscordRestUserAPI _userApi;
+    private readonly Utility _utility;
+
+    public ClearCommandGroup(
+        IDiscordRestChannelAPI channelApi, ICommandContext context, GuildDataService guildData,
+        IFeedbackService feedback, IDiscordRestUserAPI userApi, Utility utility)
+    {
+        _channelApi = channelApi;
+        _context = context;
+        _guildData = guildData;
+        _feedback = feedback;
+        _userApi = userApi;
+        _utility = utility;
+    }
+
+    /// <summary>
+    ///     A slash command that clears messages in the channel it was executed, optionally filtering by message author.
+    /// </summary>
+    /// <param name="amount">The amount of messages to clear.</param>
+    /// <param name="author">The user whose messages will be cleared.</param>
+    /// <returns>
+    ///     A feedback sending result which may or may not have succeeded. A successful result does not mean that any messages
+    ///     were cleared and vice-versa.
+    /// </returns>
+    [Command("clear", "очистить")]
+    [DiscordDefaultMemberPermissions(DiscordPermission.ManageMessages)]
+    [DiscordDefaultDMPermission(false)]
+    [RequireContext(ChannelContext.Guild)]
+    [RequireDiscordPermission(DiscordPermission.ManageMessages)]
+    [RequireBotDiscordPermissions(DiscordPermission.ManageMessages)]
+    [Description("Remove multiple messages")]
+    [UsedImplicitly]
+    public async Task<Result> ExecuteClear(
+        [Description("Number of messages to remove (2-100)")] [MinValue(2)] [MaxValue(100)]
+        int amount,
+        IUser? author = null)
+    {
+        if (!_context.TryGetContextIDs(out var guildId, out var channelId, out var executorId))
+        {
+            return new ArgumentInvalidError(nameof(_context), "Unable to retrieve necessary IDs from command context");
+        }
+
+        // The bot's avatar is used when sending messages
+        var botResult = await _userApi.GetCurrentUserAsync(CancellationToken);
+        if (!botResult.IsDefined(out var bot))
+        {
+            return ResultExtensions.FromError(botResult);
+        }
+
+        var executorResult = await _userApi.GetUserAsync(executorId, CancellationToken);
+        if (!executorResult.IsDefined(out var executor))
+        {
+            return ResultExtensions.FromError(executorResult);
+        }
+
+        var messagesResult = await _channelApi.GetChannelMessagesAsync(
+            channelId, limit: amount + 1, ct: CancellationToken);
+        if (!messagesResult.IsDefined(out var messages))
+        {
+            return ResultExtensions.FromError(messagesResult);
+        }
+
+        var data = await _guildData.GetData(guildId, CancellationToken);
+        Messages.Culture = GuildSettings.Language.Get(data.Settings);
+
+        return await ClearMessagesAsync(executor, author, data, channelId, messages, bot, CancellationToken);
+    }
+
+    private async Task<Result> ClearMessagesAsync(
+        IUser executor, IUser? author, GuildData data, Snowflake channelId, IReadOnlyList<IMessage> messages, IUser bot,
+        CancellationToken ct = default)
+    {
+        var idList = new List<Snowflake>(messages.Count);
+
+        var logEntries = new List<ClearedMessageEntry> { new() };
+        var currentLogEntry = 0;
+        for (var i = messages.Count - 1; i >= 1; i--) // '>= 1' to skip last message ('Octobot is thinking...')
+        {
+            var message = messages[i];
+            if (author is not null && message.Author.ID != author.ID)
+            {
+                continue;
+            }
+
+            idList.Add(message.ID);
+
+            var entry = logEntries[currentLogEntry];
+            var str = $"{string.Format(Messages.MessageFrom, Mention.User(message.Author))}\n{message.Content.InBlockCode()}";
+            if (entry.Builder.Length + str.Length > EmbedConstants.MaxDescriptionLength)
+            {
+                logEntries.Add(entry = new ClearedMessageEntry());
+                currentLogEntry++;
+            }
+
+            entry.Builder.Append(str);
+            entry.DeletedCount++;
+        }
+
+        if (idList.Count == 0)
+        {
+            var failedEmbed = new EmbedBuilder().WithSmallTitle(Messages.NoMessagesToClear, bot)
+                .WithColour(ColorsList.Red).Build();
+
+            return await _feedback.SendContextualEmbedResultAsync(failedEmbed, ct: ct);
+        }
+
+        var title = author is not null
+            ? string.Format(Messages.MessagesClearedFiltered, idList.Count.ToString(), author.GetTag())
+            : string.Format(Messages.MessagesCleared, idList.Count.ToString());
+
+        var deleteResult = await _channelApi.BulkDeleteMessagesAsync(
+            channelId, idList, executor.GetTag().EncodeHeader(), ct);
+        if (!deleteResult.IsSuccess)
+        {
+            return ResultExtensions.FromError(deleteResult);
+        }
+
+        foreach (var log in logEntries)
+        {
+            _utility.LogAction(
+                data.Settings, channelId, executor, author is not null
+                    ? string.Format(Messages.MessagesClearedFiltered, log.DeletedCount.ToString(), author.GetTag())
+                    : string.Format(Messages.MessagesCleared, log.DeletedCount.ToString()),
+                log.Builder.ToString(), bot, ColorsList.Red, false, ct);
+        }
+
+        var embed = new EmbedBuilder().WithSmallTitle(title, bot)
+            .WithColour(ColorsList.Green).Build();
+
+        return await _feedback.SendContextualEmbedResultAsync(embed, ct: ct);
+    }
+
+    private sealed class ClearedMessageEntry
+    {
+        public StringBuilder Builder { get; } = new();
+        public int DeletedCount { get; set; }
+    }
+}