Added support for animated emoji (#913)

* Added support for animated emoji

This was such a useful feature Discord, I'm glad you added this instead
of fixing bugs.

* Fix bugs in emote parser

* Added unit tests for emotes

src/Discord.Net.Core/CDN.cs

@@ -19,8 +19,8 @@ namespace Discord
             => splashId != null ? $"{DiscordConfig.CDNUrl}splashes/{guildId}/{splashId}.jpg" : null;
         public static string GetChannelIconUrl(ulong channelId, string iconId)
             => iconId != null ? $"{DiscordConfig.CDNUrl}channel-icons/{channelId}/{iconId}.jpg" : null;
-        public static string GetEmojiUrl(ulong emojiId)
-            => $"{DiscordConfig.CDNUrl}emojis/{emojiId}.png";
+        public static string GetEmojiUrl(ulong emojiId, bool animated)
+            => $"{DiscordConfig.CDNUrl}emojis/{emojiId}.{(animated ? "gif" : "png")}";
 
         public static string GetRichAssetUrl(ulong appId, string assetId, ushort size, ImageFormat format)
         {

src/Discord.Net.Core/Entities/Emotes/Emote.cs

@@ -16,13 +16,18 @@ namespace Discord
         /// The ID of this emote
         /// </summary>
         public ulong Id { get; }
+        /// <summary>
+        /// Is this emote animated?
+        /// </summary>
+        public bool Animated { get; }
         public DateTimeOffset CreatedAt => SnowflakeUtils.FromSnowflake(Id);
-        public string Url => CDN.GetEmojiUrl(Id);
+        public string Url => CDN.GetEmojiUrl(Id, Animated);
 
-        internal Emote(ulong id, string name)
+        internal Emote(ulong id, string name, bool animated)
         {
             Id = id;
             Name = name;
+            Animated = animated;
         }
 
         public override bool Equals(object other)
@@ -59,17 +64,20 @@ namespace Discord
         public static bool TryParse(string text, out Emote result)
         {
             result = null;
-            if (text.Length >= 4 && text[0] == '<' && text[1] == ':' && text[text.Length - 1] == '>')
+            if (text.Length >= 4 && text[0] == '<' && (text[1] == ':' || (text[1] == 'a' && text[2] == ':')) && text[text.Length - 1] == '>')
             {
-                int splitIndex = text.IndexOf(':', 2);
+                bool animated = text[1] == 'a';
+                int startIndex = animated ? 3 : 2;
+
+                int splitIndex = text.IndexOf(':', startIndex);
                 if (splitIndex == -1)
                     return false;
 
                 if (!ulong.TryParse(text.Substring(splitIndex + 1, text.Length - splitIndex - 2), NumberStyles.None, CultureInfo.InvariantCulture, out ulong id))
                     return false;
 
-                string name = text.Substring(2, splitIndex - 2);
-                result = new Emote(id, name);
+                string name = text.Substring(startIndex, splitIndex - startIndex);
+                result = new Emote(id, name, animated);
                 return true;
             }
             return false;
@@ -77,6 +85,6 @@ namespace Discord
         }
 
         private string DebuggerDisplay => $"{Name} ({Id})";
-        public override string ToString() => $"<:{Name}:{Id}>";
+        public override string ToString() => $"<{(Animated ? "a" : "")}:{Name}:{Id}>";
     }
 }

src/Discord.Net.Core/Entities/Emotes/GuildEmote.cs

@@ -13,7 +13,7 @@ namespace Discord
         public bool RequireColons { get; }
         public IReadOnlyList<ulong> RoleIds { get; }
 
-        internal GuildEmote(ulong id, string name, bool isManaged, bool requireColons, IReadOnlyList<ulong> roleIds) : base(id, name)
+        internal GuildEmote(ulong id, string name, bool animated, bool isManaged, bool requireColons, IReadOnlyList<ulong> roleIds) : base(id, name, animated)
         {
             IsManaged = isManaged;
             RequireColons = requireColons;
@@ -21,6 +21,6 @@ namespace Discord
         }
 
         private string DebuggerDisplay => $"{Name} ({Id})";
-        public override string ToString() => $"<:{Name}:{Id}>";
+        public override string ToString() => $"<{(Animated ? "a" : "")}:{Name}:{Id}>";
     }
 }