added UserDefaultAvatar to IUser (#973)

* added UserDefaultAvatar to IUser

* pass ushort as discriminator

* removed unneeded ushort.parse

src/Discord.Net.Core/CDN.cs

@@ -13,6 +13,10 @@ namespace Discord
             string extension = FormatToExtension(format, avatarId);
             return $"{DiscordConfig.CDNUrl}avatars/{userId}/{avatarId}.{extension}?size={size}";
         }
+        public static string GetDefaultUserAvatarUrl(ushort discriminator)
+        {
+            return $"{DiscordConfig.CDNUrl}embed/avatars/{discriminator % 5}.png";
+        }
         public static string GetGuildIconUrl(ulong guildId, string iconId)
             => iconId != null ? $"{DiscordConfig.CDNUrl}icons/{guildId}/{iconId}.jpg" : null;
         public static string GetGuildSplashUrl(ulong guildId, string splashId)
@@ -37,11 +41,16 @@ namespace Discord
                 format = imageId.StartsWith("a_") ? ImageFormat.Gif : ImageFormat.Png;
             switch (format)
             {
-                case ImageFormat.Gif: return "gif";
+                case ImageFormat.Gif:
-                case ImageFormat.Jpeg: return "jpeg";
+                    return "gif";
-                case ImageFormat.Png: return "png";
+                case ImageFormat.Jpeg:
-                case ImageFormat.WebP: return "webp";
+                    return "jpeg";
-                default: throw new ArgumentException(nameof(format));
+                case ImageFormat.Png:
+                    return "png";
+                case ImageFormat.WebP:
+                    return "webp";
+                default:
+                    throw new ArgumentException(nameof(format));
             }
         }
     }

src/Discord.Net.Core/Entities/Users/IUser.cs

@@ -8,6 +8,8 @@ namespace Discord
         string AvatarId { get; }
         /// <summary> Gets the url to this user's avatar. </summary>
         string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128);
+        /// <summary> Gets the url to this user's default avatar. </summary>
+        string GetDefaultAvatarUrl();
         /// <summary> Gets the per-username unique id for this user. </summary>
         string Discriminator { get; }
         /// <summary> Gets the per-username unique id for this user. </summary>

src/Discord.Net.Rest/Entities/Users/RestUser.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Diagnostics;
 using System.Threading.Tasks;
 using Model = Discord.API.User;
@@ -60,6 +60,9 @@ namespace Discord.Rest
         public string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128)
             => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
 
+        public string GetDefaultAvatarUrl()
+            => CDN.GetDefaultUserAvatarUrl(DiscriminatorValue);
+
         public override string ToString() => $"{Username}#{Discriminator}";
         private string DebuggerDisplay => $"{Username}#{Discriminator} ({Id}{(IsBot ? ", Bot" : "")})";
 

src/Discord.Net.WebSocket/Entities/Users/SocketUser.cs

@@ -1,4 +1,4 @@
-using Discord.Rest;
+using Discord.Rest;
 using System;
 using System.Threading.Tasks;
 using Model = Discord.API.User;
@@ -61,6 +61,9 @@ namespace Discord.WebSocket
         public string GetAvatarUrl(ImageFormat format = ImageFormat.Auto, ushort size = 128)
             => CDN.GetUserAvatarUrl(Id, AvatarId, size, format);
 
+        public string GetDefaultAvatarUrl()
+            => CDN.GetDefaultUserAvatarUrl(DiscriminatorValue);
+
         public override string ToString() => $"{Username}#{Discriminator}";
         private string DebuggerDisplay => $"{Username}#{Discriminator} ({Id}{(IsBot ? ", Bot" : "")})";
         internal SocketUser Clone() => MemberwiseClone() as SocketUser;