Check if referenced message contains an emote when fetching images for image effect commands

Author: selfdocumentingcode

src/Kattbot.Common/Models/Emotes/TempEmote.cs

@@ -7,4 +7,6 @@ public class TempEmote
     public string Name { get; set; } = null!;
 
     public bool Animated { get; set; }
+
+    public string ImageUrl { get; set; } = null!;
 }

src/Kattbot/Helpers/DiscordExtensions.cs

@@ -1,9 +1,9 @@
 using System;
-using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using DSharpPlus.Entities;
+using Kattbot.Common.Models.Emotes;
 using Microsoft.Extensions.Logging;
 
 namespace Kattbot.Helpers;
@@ -109,6 +109,17 @@ public static string SubstituteMentions(this DiscordMessage message)
                     referencedMessage.Id);
                 return imageUrl;
             }
+
+            TempEmote? singleEmojiParsedFromMessage = EmoteHelper.Parse(referencedMessage.Content.Trim());
+
+            if (singleEmojiParsedFromMessage != null)
+            {
+                logger?.LogDebug(
+                    "Found single emoji image url {ImageUrl} in referenced message {ReferencedMessageId}",
+                    singleEmojiParsedFromMessage.ImageUrl,
+                    referencedMessage.Id);
+                return singleEmojiParsedFromMessage.ImageUrl;
+            }
         }
 
         logger?.LogDebug("Waiting for embed image in message {MessageId}", message.Id);

src/Kattbot/Helpers/EmoteHelper.cs

@@ -1,4 +1,8 @@
-using System.Text;
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
 using System.Text.RegularExpressions;
 using DSharpPlus.Entities;
 using Kattbot.Common.Models.Emotes;
@@ -7,11 +11,12 @@ namespace Kattbot.Helpers;
 
 public static class EmoteHelper
 {
-    public static readonly Regex EmoteRegex = new(@"<a{0,1}:\w+:\d+>");
-    public static readonly Regex EmoteRegexGrouped = new(@"<(a{0,1}):(\w+):(\d+)>");
-    public static readonly string EmoteCodeFormat = "<:{0}:{1}>";
-    public static readonly string EmoteAnimatedCodeFormat = "<a:{0}:{1}>";
-    public static readonly string EmoteNamePlaceholder = "x";
+    private const string EmoteCodeFormat = "<:{0}:{1}>";
+    private const string EmoteAnimatedCodeFormat = "<a:{0}:{1}>";
+    private const string EmoteNamePlaceholder = "x";
+
+    private static readonly Regex EmoteRegex = new(@"<a{0,1}:\w+:\d+>");
+    private static readonly Regex EmoteRegexGrouped = new(@"<(a{0,1}):(\w+):(\d+)>");
 
     public static TempEmote? Parse(string emoteString)
     {
@@ -32,6 +37,7 @@ public static class EmoteHelper
             Id = id,
             Name = name,
             Animated = isAnimated,
+            ImageUrl = BuildDiscordEmojiUrl(id, isAnimated),
         };
 
         return parsed;
@@ -74,7 +80,7 @@ public static string GetExternalEmojiImageUrl(string code)
 
         // flag =  0001F1E6 0001F1E9
         // https://emoji.aranja.com/static/emoji-data/img-twitter-72/1f1e6-1f1e9.png
-        var utf32Encoding = new UTF32Encoding(true, false);
+        var utf32Encoding = new UTF32Encoding(bigEndian: true, byteOrderMark: false);
 
         byte[] bytes = utf32Encoding.GetBytes(code);
 
@@ -90,7 +96,7 @@ public static string GetExternalEmojiImageUrl(string code)
 
         for (var i = 0; i < bytesAsString.Length; i += 8)
         {
-            string unicodePart = bytesAsString.Substring(i, 8)
+            string unicodePart = bytesAsString.Substring(i, length: 8)
                 .TrimStart('0')
                 .ToLower();
 
@@ -101,4 +107,22 @@ public static string GetExternalEmojiImageUrl(string code)
 
         return $"https://emoji.aranja.com/static/emoji-data/img-twitter-72/{fileName}.png";
     }
+
+    public static List<string> ExtractEmotesFromMessage(string messageText)
+    {
+        MatchCollection result = EmoteRegex.Matches(messageText);
+
+        List<string> emojiStrings = result.Select(m => m.Value).ToList();
+
+        return emojiStrings;
+    }
+
+    private static string BuildDiscordEmojiUrl(ulong id, bool isAnimated)
+    {
+        return id == 0
+            ? throw new InvalidOperationException("Cannot get URL of unicode emojis.")
+            : isAnimated
+                ? $"https://cdn.discordapp.com/emojis/{id.ToString(CultureInfo.InvariantCulture)}.gif"
+                : $"https://cdn.discordapp.com/emojis/{id.ToString(CultureInfo.InvariantCulture)}.png";
+    }
 }

src/Kattbot/Program.cs

@@ -68,7 +68,6 @@ private static void AddInternalServices(IServiceCollection services)
     {
         services.AddTransient<EmoteEntityBuilder>();
         services.AddTransient<DateTimeProvider>();
-        services.AddTransient<EmoteParser>();
         services.AddTransient<GuildSettingsService>();
         services.AddTransient<ImageService>();
         services.AddTransient<DiscordErrorLogger>();

src/Kattbot/Services/EmoteEntityBuilder.cs

@@ -9,41 +9,33 @@ namespace Kattbot.Services;
 
 public class EmoteEntityBuilder
 {
-    private readonly EmoteParser _emoteParser;
-
-    public EmoteEntityBuilder(EmoteParser emoteParser)
-    {
-        _emoteParser = emoteParser;
-    }
-
     public List<EmoteEntity> BuildFromSocketUserMessage(DiscordMessage message, ulong guildId)
     {
-        List<string> emojiStrings = _emoteParser.ExtractEmotesFromMessage(message.Content);
+        List<string> emojiStrings = EmoteHelper.ExtractEmotesFromMessage(message.Content);
 
-        List<EmoteEntity> emotes = emojiStrings.Select(
-                s =>
-                {
-                    TempEmote? parsedEmote = EmoteHelper.Parse(s);
-
-                    if (parsedEmote == null)
-                    {
-                        throw new Exception($"{s} is not a valid emote string");
-                    }
+        List<EmoteEntity> emotes = emojiStrings.Select(s =>
+            {
+                TempEmote? parsedEmote = EmoteHelper.Parse(s);
 
-                    var emoteEntitiy = new EmoteEntity
-                    {
-                        EmoteId = parsedEmote.Id,
-                        EmoteName = parsedEmote.Name,
-                        EmoteAnimated = parsedEmote.Animated,
-                        DateTime = DateTimeOffset.UtcNow,
-                        UserId = message.Author.Id,
-                        MessageId = message.Id,
-                        GuildId = guildId,
-                        Source = EmoteSource.Message,
-                    };
+                if (parsedEmote == null)
+                {
+                    throw new Exception($"{s} is not a valid emote string");
+                }
 
-                    return emoteEntitiy;
-                })
+                var emoteEntity = new EmoteEntity
+                {
+                    EmoteId = parsedEmote.Id,
+                    EmoteName = parsedEmote.Name,
+                    EmoteAnimated = parsedEmote.Animated,
+                    DateTime = DateTimeOffset.UtcNow,
+                    UserId = message.Author.Id,
+                    MessageId = message.Id,
+                    GuildId = guildId,
+                    Source = EmoteSource.Message,
+                };
+
+                return emoteEntity;
+            })
             .ToList();
 
         return emotes;

src/Kattbot/Services/EmoteParser.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Kattbot.Helpers;
 using Kattbot.Services;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -7,32 +8,24 @@ namespace Kattbot.Tests;
 [TestClass]
 public class EmoteParserTests
 {
-    private EmoteParser _sut = null!;
-
-    [TestInitialize]
-    public void Initialize()
-    {
-        _sut = new EmoteParser();
-    }
-
     [TestMethod]
     public void ParseEmotes_WithMessageContaingEmotes_ReturnEmote()
     {
         const string testMessage = "Some text <:emoji_1:123123123>";
 
-        List<string> emotes = _sut.ExtractEmotesFromMessage(testMessage);
+        List<string> emotes = EmoteHelper.ExtractEmotesFromMessage(testMessage);
 
-        Assert.AreEqual(emotes.Count, actual: 1);
-        Assert.AreEqual(emotes[0], "<:emoji_1:123123123>");
+        Assert.HasCount(expected: 1, emotes);
+        Assert.AreEqual("<:emoji_1:123123123>", emotes[0]);
     }
 
     [TestMethod]
     public void ParseEmotes_WithMessageContaingThreeEmotes_ReturnThreeEmotes()
     {
         const string testMessage = "Some text <:emoji_1:123123123> other <:emoji_2:123123123><:emoji_3:123123123>";
 
-        List<string> emotes = _sut.ExtractEmotesFromMessage(testMessage);
+        List<string> emotes = EmoteHelper.ExtractEmotesFromMessage(testMessage);
 
-        Assert.AreEqual(emotes.Count, actual: 3);
+        Assert.HasCount(expected: 3, emotes);
     }
 }