From 4f4e16d674daabee148f599f5f78a8975dec0c6a Mon Sep 17 00:00:00 2001
From: Daan Boerlage <d@boerlage.me>
Date: Tue, 9 Nov 2021 00:51:37 +0100
Subject: [PATCH] Add a way to lookup all bot commands in the bot assembly
 without using the commandService provided by discord.net

---
 src/Core/BotCommandLookup/CommandInfo.cs   | 11 +++
 src/Core/BotCommandLookup/CommandLookup.cs | 87 ++++++++++++++++++++++
 src/Core/BotCommandLookup/ParameterInfo.cs |  8 ++
 3 files changed, 106 insertions(+)
 create mode 100644 src/Core/BotCommandLookup/CommandInfo.cs
 create mode 100644 src/Core/BotCommandLookup/CommandLookup.cs
 create mode 100644 src/Core/BotCommandLookup/ParameterInfo.cs

diff --git a/src/Core/BotCommandLookup/CommandInfo.cs b/src/Core/BotCommandLookup/CommandInfo.cs
new file mode 100644
index 0000000..c5793ac
--- /dev/null
+++ b/src/Core/BotCommandLookup/CommandInfo.cs
@@ -0,0 +1,11 @@
+using System.Collections.Generic;
+
+namespace Geekbot.Core.BotCommandLookup;
+
+public struct CommandInfo
+{
+    public string Name { get; set; }
+    public Dictionary<string, ParameterInfo> Parameters { get; set; }
+    public List<string> Aliases { get; set; }
+    public string Summary { get; set; }
+}
\ No newline at end of file
diff --git a/src/Core/BotCommandLookup/CommandLookup.cs b/src/Core/BotCommandLookup/CommandLookup.cs
new file mode 100644
index 0000000..09fadf2
--- /dev/null
+++ b/src/Core/BotCommandLookup/CommandLookup.cs
@@ -0,0 +1,87 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Discord.Commands;
+
+namespace Geekbot.Core.BotCommandLookup;
+
+public class CommandLookup
+{
+    private readonly Assembly _assembly;
+
+    public CommandLookup(Assembly assembly)
+    {
+        _assembly = assembly;
+    }
+    
+    public List<CommandInfo> GetCommands()
+    {
+        var commands = SearchCommands(_assembly);
+        var result = new List<CommandInfo>();
+        commands.ForEach(x => GetCommandDefinition(ref result, x));
+
+        return result;
+    }
+
+    private List<TypeInfo> SearchCommands(Assembly assembly)
+    {
+        bool IsLoadableModule(TypeInfo info) => info.DeclaredMethods.Any(x => x.GetCustomAttribute<CommandAttribute>() != null || x.GetCustomAttribute<GroupAttribute>() != null);
+        return assembly
+            .DefinedTypes
+            .Where(typeInfo => typeInfo.IsPublic || typeInfo.IsNestedPublic)
+            .Where(IsLoadableModule)
+            .ToList();
+    }
+
+    private void GetCommandDefinition(ref List<CommandInfo> commandInfos, TypeInfo commandType)
+    {
+        var methods = commandType
+            .GetMethods()
+            .Where(x => x.GetCustomAttribute<CommandAttribute>() != null)
+            .ToList();
+
+        var commandGroup = (commandType.GetCustomAttributes().FirstOrDefault(attr => attr is GroupAttribute) as GroupAttribute)?.Prefix;
+
+        foreach (var command in methods)
+        {
+            var commandInfo = new CommandInfo()
+            {
+                Parameters = new Dictionary<string, ParameterInfo>(),
+            };
+            
+            foreach (var attr in command.GetCustomAttributes())
+            {
+                
+                switch (attr)
+                {
+                    case SummaryAttribute name:
+                        commandInfo.Summary = name.Text;
+                        break;
+                    case CommandAttribute name:
+                        commandInfo.Name = string.IsNullOrEmpty(commandGroup) ? name.Text : $"{commandGroup} {name.Text}";
+                        break;
+                    case AliasAttribute name:
+                        commandInfo.Aliases = name.Aliases.ToList() ?? new List<string>();
+                        break;
+                }
+            }
+
+            foreach (var param in command.GetParameters())
+            {
+                var paramName = param.Name ?? string.Empty;
+                var paramInfo = new ParameterInfo()
+                {
+                    Summary = param.GetCustomAttribute<SummaryAttribute>()?.Text ?? string.Empty,
+                    Type = param.ParameterType.Name,
+                    DefaultValue = param.DefaultValue?.ToString() ?? string.Empty
+                };
+                commandInfo.Parameters.Add(paramName, paramInfo);
+            }
+            
+            if (!string.IsNullOrEmpty(commandInfo.Name))
+            {
+                commandInfos.Add(commandInfo);                    
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Core/BotCommandLookup/ParameterInfo.cs b/src/Core/BotCommandLookup/ParameterInfo.cs
new file mode 100644
index 0000000..afdfd50
--- /dev/null
+++ b/src/Core/BotCommandLookup/ParameterInfo.cs
@@ -0,0 +1,8 @@
+namespace Geekbot.Core.BotCommandLookup;
+
+public struct ParameterInfo
+{
+    public string Summary { get; set; }
+    public string Type { get; set; }
+    public string DefaultValue { get; set; }
+}
\ No newline at end of file