Improve performance (#162)

DiscordChatExporter.Core.Models/User.cs

@@ -0,0 +1,58 @@
+using System;
+
+namespace DiscordChatExporter.Core.Models
+{
+    // https://discordapp.com/developers/docs/topics/permissions#role-object
+
+    public partial class User
+    {
+        public string Id { get; }
+
+        public int Discriminator { get; }
+
+        public string Name { get; }
+
+        public string FullName { get; }
+
+        public string AvatarHash { get; }
+
+        public string AvatarUrl { get; }
+
+        public User(string id, int discriminator, string name, string avatarHash)
+        {
+            Id = id;
+            Discriminator = discriminator;
+            Name = name;
+            AvatarHash = avatarHash;
+
+            FullName = GetFullName(name, discriminator);
+            AvatarUrl = GetAvatarUrl(id, discriminator, avatarHash);
+        }
+
+        public override string ToString() => FullName;
+    }
+
+    public partial class User
+    {
+        public static string GetFullName(string name, int discriminator) => $"{name}#{discriminator:0000}";
+
+        public static string GetAvatarUrl(string id, int discriminator, string avatarHash)
+        {
+            // Custom avatar
+            if (avatarHash != null)
+            {
+                // Animated
+                if (avatarHash.StartsWith("a_", StringComparison.Ordinal))
+                    return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.gif";
+
+                // Non-animated
+                return $"https://cdn.discordapp.com/avatars/{id}/{avatarHash}.png";
+            }
+
+            // Default avatar
+            return $"https://cdn.discordapp.com/embed/avatars/{discriminator % 5}.png";
+        }
+
+        public static User CreateUnknownUser(string id) => new User(id, 0, "Unknown", null);
+    }
+}