Redesigned the DiscordBotCore by splitting it into multiple projects. Created a WebUI and preparing to remove the DiscordBot application

DiscordBotCore.PluginManagement.Loading/Loader.cs

@@ -0,0 +1,81 @@
+using System.Reflection;
+using DiscordBotCore.PluginCore;
+using DiscordBotCore.PluginCore.Interfaces;
+using DiscordBotCore.PluginManagement.Loading.Exceptions;
+
+namespace DiscordBotCore.PluginManagement.Loading;
+
+internal class Loader
+{
+    internal delegate void FileLoadedHandler(string fileName, Exception exception);
+    internal delegate void PluginLoadedHandler(PluginLoaderResult result);
+
+    internal event FileLoadedHandler? OnFileLoadedException;
+    internal event PluginLoadedHandler? OnPluginLoaded;
+    
+    private readonly IPluginManager _pluginManager;
+
+    internal Loader(IPluginManager manager)
+    {
+        _pluginManager = manager;
+    }
+
+    internal async Task Load()
+    {
+        var installedPlugins = await _pluginManager.GetInstalledPlugins();
+        var files            = installedPlugins.Where(plugin => plugin.IsEnabled).Select(plugin => plugin.FilePath).ToArray();
+
+        foreach (var file in files)
+        {
+            try
+            {
+                Assembly.LoadFrom(file);
+            }
+            catch
+            {
+                OnFileLoadedException?.Invoke(file, new Exception($"Failed to load plugin from file {file}"));
+            }
+        }
+
+        await LoadEverythingOfType<IDbEvent>();
+        await LoadEverythingOfType<IDbCommand>();
+        await LoadEverythingOfType<IDbSlashCommand>();
+    }
+
+    private Task LoadEverythingOfType<T>()
+    {
+        var types = AppDomain.CurrentDomain.GetAssemblies()
+                             .SelectMany(s => s.GetTypes())
+                             .Where(p => typeof(T).IsAssignableFrom(p) && !p.IsInterface);
+
+        foreach (var type in types)
+        {
+            try
+            {
+                var plugin = (T?)Activator.CreateInstance(type);
+
+                if (plugin is null)
+                {
+                    throw new Exception($"Failed to create instance of plugin with type {type.FullName} [{type.Assembly}]");
+                }
+
+                PluginLoaderResult result = plugin switch
+                {
+                    IDbEvent @event         => PluginLoaderResult.FromIDbEvent(@event),
+                    IDbCommand command      => PluginLoaderResult.FromIDbCommand(command),
+                    IDbSlashCommand command => PluginLoaderResult.FromIDbSlashCommand(command),
+                    _                       => PluginLoaderResult.FromException(new PluginNotFoundException($"Unknown plugin type {plugin.GetType().FullName}"))
+                };
+
+                OnPluginLoaded?.Invoke(result);
+            }
+            catch (Exception ex)
+            {
+                OnPluginLoaded?.Invoke(PluginLoaderResult.FromException(ex));
+            }
+        }
+        
+        return Task.CompletedTask;
+    }
+
+}