Fix crash when parsing position on DM channels (#496)

DiscordChatExporter.Cli/Commands/GetDirectMessageChannelsCommand.cs

@@ -16,7 +16,7 @@ namespace DiscordChatExporter.Cli.Commands
         {
             var channels = await GetDiscordClient().GetGuildChannelsAsync(Guild.DirectMessages.Id);
 
-            foreach (var channel in channels.OrderBy(c => c.Category, PositionBasedComparer.Instance).ThenBy(c => c.Name))
+            foreach (var channel in channels.OrderBy(c => c.Name))
                 console.Output.WriteLine($"{channel.Id} | {channel.Category} / {channel.Name}");
         }
     }

DiscordChatExporter.Domain/Discord/Models/Channel.cs

@@ -41,11 +41,11 @@ namespace DiscordChatExporter.Domain.Discord.Models
 
         public string Name { get; }
 
-        public int Position { get; }
+        public int? Position { get; }
 
         public string? Topic { get; }
 
-        public Channel(Snowflake id, ChannelType type, Snowflake guildId, ChannelCategory? category, string name, int position, string? topic)
+        public Channel(Snowflake id, ChannelType type, Snowflake guildId, ChannelCategory? category, string name, int? position, string? topic)
         {
             Id = id;
             Type = type;
@@ -89,15 +89,15 @@ namespace DiscordChatExporter.Domain.Discord.Models
                 json.GetPropertyOrNull("recipients")?.EnumerateArray().Select(User.Parse).Select(u => u.Name).JoinToString(", ") ??
                 id.ToString();
 
-            position ??= json.GetProperty("position").GetInt32();
-            
+            position ??= json.GetPropertyOrNull("position")?.GetInt32();
+
             return new Channel(
                 id,
                 type,
                 guildId ?? Guild.DirectMessages.Id,
                 category ?? GetDefaultCategory(type),
                 name,
-                position.Value,
+                position,
                 topic
             );
         }

DiscordChatExporter.Domain/Discord/Models/ChannelCategory.cs

@@ -14,9 +14,9 @@ namespace DiscordChatExporter.Domain.Discord.Models
 
         public string Name { get; }
 
-        public int Position { get; }
+        public int? Position { get; }
 
-        public ChannelCategory(Snowflake id, string name, int position)
+        public ChannelCategory(Snowflake id, string name, int? position)
         {
             Id = id;
             Name = name;
@@ -32,7 +32,7 @@ namespace DiscordChatExporter.Domain.Discord.Models
         public static ChannelCategory Parse(JsonElement json, int? position = null)
         {
             var id = json.GetProperty("id").GetString().Pipe(Snowflake.Parse);
-            position ??= json.GetProperty("position").GetInt32();
+            position ??= json.GetPropertyOrNull("position")?.GetInt32();
 
             var name = json.GetPropertyOrNull("name")?.GetString() ??
                 json.GetPropertyOrNull("recipients")?.EnumerateArray().Select(User.Parse).Select(u => u.Name).JoinToString(", ") ??
@@ -41,7 +41,7 @@ namespace DiscordChatExporter.Domain.Discord.Models
             return new ChannelCategory(
                 id,
                 name,
-                position.Value
+                position
             );
         }
 

DiscordChatExporter.Domain/Discord/Models/Common/IHasIdAndPosition.cs

@@ -2,6 +2,6 @@
 {
     public interface IHasIdAndPosition : IHasId
     {
-        int Position { get; }
+        int? Position { get; }
     }
 }

DiscordChatExporter.Domain/Discord/Models/Common/PositionBasedComparer.cs

@@ -6,18 +6,10 @@ namespace DiscordChatExporter.Domain.Discord.Models.Common
     {
         public int Compare(IHasIdAndPosition? x, IHasIdAndPosition? y)
         {
-            int result;
-            if (x != null)
+            int result = Comparer<int?>.Default.Compare(x?.Position, y?.Position);
+            if (result == 0)
             {
-                result = x.Position.CompareTo(y?.Position);
-                if(result == 0)
-                {
-                    result = x.Id.Value.CompareTo(y?.Id.Value);
-                }
-            }
-            else
-            {
-                result = y == null ? 0 : -1;
+                result = Comparer<ulong?>.Default.Compare(x?.Id.Value, y?.Id.Value);
             }
             return result;
         }

DiscordChatExporter.Domain/Exporting/ExportRequest.cs

@@ -94,8 +94,8 @@ namespace DiscordChatExporter.Domain.Exporting
                     "%T" => channel.Category.Name,
                     "%c" => channel.Id.ToString(),
                     "%C" => channel.Name,
-                    "%p" => channel.Position.ToString(),
-                    "%P" => channel.Category.Position.ToString(),
+                    "%p" => channel.Position?.ToString() ?? "0",
+                    "%P" => channel.Category.Position?.ToString() ?? "0",
                     "%a" => (after ?? Snowflake.Zero).ToDate().ToString("yyyy-MM-dd"),
                     "%b" => (before?.ToDate() ?? DateTime.Now).ToString("yyyy-MM-dd"),
                     "%%" => "%",

DiscordChatExporter.Gui/Views/RootView.xaml

@@ -27,7 +27,7 @@
     <Window.Resources>
         <CollectionViewSource x:Key="AvailableChannelsViewSource" Source="{Binding AvailableChannels, Mode=OneWay}">
             <CollectionViewSource.GroupDescriptions>
-                <PropertyGroupDescription PropertyName="Category" />
+                <PropertyGroupDescription PropertyName="Category.Name" />
             </CollectionViewSource.GroupDescriptions>
             <CollectionViewSource.SortDescriptions>
                 <componentModel:SortDescription Direction="Ascending" PropertyName="Position" />