Added modular event system

src/HopFrame.Core/Config/DbContextConfig.cs

@@ -1,13 +1,16 @@
-using Microsoft.EntityFrameworkCore;
+using HopFrame.Core.Events;
+using Microsoft.EntityFrameworkCore;
 
 namespace HopFrame.Core.Config;
 
 public class DbContextConfig {
     public Type ContextType { get; }
     public List<TableConfig> Tables { get; } = new();
+    public HopFrameConfig ParentConfig { get; }
 
-    public DbContextConfig(Type context) {
+    public DbContextConfig(Type context, HopFrameConfig parentConfig) {
         ContextType = context;
+        ParentConfig = parentConfig;
 
         foreach (var property in ContextType.GetProperties()) {
             if (!property.PropertyType.IsGenericType) continue;

src/HopFrame.Core/Config/HopFrameConfig.cs

@@ -1,4 +1,5 @@
-using Microsoft.EntityFrameworkCore;
+using HopFrame.Core.Events;
+using Microsoft.EntityFrameworkCore;
 
 namespace HopFrame.Core.Config;
 
@@ -7,6 +8,7 @@ public class HopFrameConfig {
     public bool DisplayUserInfo { get; set; } = true;
     public string? BasePolicy { get; set; }
     public string? LoginPageRewrite { get; set; }
+    public List<HopEventHandler> Handlers { get; } = new();
 }
 
 /// <summary>
@@ -38,7 +40,7 @@ public class HopFrameConfigurator(HopFrameConfig config) {
     /// <returns>The configurator used for the DbContext</returns>
     /// <seealso cref="DbContextConfigurator{TDbContext}"/>
     public DbContextConfigurator<TDbContext> AddDbContext<TDbContext>() where TDbContext : DbContext {
-        var context = new DbContextConfig(typeof(TDbContext));
+        var context = new DbContextConfig(typeof(TDbContext), InnerConfig);
         InnerConfig.Contexts.Add(context);
         return new DbContextConfigurator<TDbContext>(context);
     }

src/HopFrame.Core/Config/TableConfig.cs

@@ -2,6 +2,7 @@
 using System.ComponentModel.DataAnnotations.Schema;
 using System.Linq.Expressions;
 using System.Reflection;
+using HopFrame.Core.Events;
 
 namespace HopFrame.Core.Config;
 
@@ -188,6 +189,36 @@ public class TableConfigurator<TModel>(TableConfig config) {
         InnerConfig.DeletePolicy = policy;
         return this;
     }
+
+    /// <summary>
+    /// Adds an event handler of the provided type
+    /// </summary>
+    /// <param name="type">The type of event that triggers the handler</param>
+    /// <param name="handler">The handler delegate</param>
+    public TableConfigurator<TModel> AddEventHandler(EventType type, Func<TModel, IServiceProvider, Task> handler) {
+        var eventName = EventTypes.ConstructEventName(type, InnerConfig);
+        var handlerStore = new HopEventHandler(eventName, (o, provider) => handler.Invoke((TModel)o, provider));
+        InnerConfig.ContextConfig.ParentConfig.Handlers.Add(handlerStore);
+        
+        return this;
+    }
+    
+    /// <summary>
+    /// Adds an event handler of the provided type
+    /// </summary>
+    /// <param name="type">The type of event that triggers the handler</param>
+    /// <param name="handler">The handler delegate</param>
+    public TableConfigurator<TModel> AddEventHandler(EventType type, Action<TModel, IServiceProvider> handler) {
+        var eventName = EventTypes.ConstructEventName(type, InnerConfig);
+        var handlerStore = new HopEventHandler(eventName, (o, provider) => {
+            handler.Invoke((TModel)o, provider);
+            return Task.CompletedTask;
+        });
+        
+        InnerConfig.ContextConfig.ParentConfig.Handlers.Add(handlerStore);
+        
+        return this;
+    }
     
     internal static PropertyInfo GetPropertyInfo<TSource, TProperty>(Expression<Func<TSource, TProperty>> propertyLambda) {
         if (propertyLambda.Body is not MemberExpression member) {

src/HopFrame.Core/Events/EventTypes.cs

@@ -0,0 +1,31 @@
+using HopFrame.Core.Config;
+
+namespace HopFrame.Core.Events;
+
+public static class EventTypes {
+
+    private const string Prefix = "HopFrame.";
+    private const string CreateEntryPrefix = Prefix + "Entry.Create.";
+    private const string UpdateEntryPrefix = Prefix + "Entry.Update.";
+    private const string DeleteEntryPrefix = Prefix + "Entry.Delete.";
+
+    public static string CreateEntry(TableConfig config) => CreateEntryPrefix + config.PropertyName;
+    public static string UpdateEntry(TableConfig config) => UpdateEntryPrefix + config.PropertyName;
+    public static string DeleteEntry(TableConfig config) => DeleteEntryPrefix + config.PropertyName;
+
+    public static string ConstructEventName(EventType type, TableConfig config) {
+        return type switch {
+            EventType.CreateEntry => CreateEntry(config),
+            EventType.UpdateEntry => UpdateEntry(config),
+            EventType.DeleteEntry => DeleteEntry(config),
+            _ => Prefix
+        };
+    }
+
+}
+
+public enum EventType {
+    CreateEntry = 0,
+    UpdateEntry = 1,
+    DeleteEntry = 2
+}

src/HopFrame.Core/Events/HopEventHandler.cs

@@ -0,0 +1,7 @@
+namespace HopFrame.Core.Events;
+
+public readonly struct HopEventHandler(string eventType, Func<object, IServiceProvider, Task> handler) {
+    public Guid Id { get; } = Guid.CreateVersion7();
+    public Func<object, IServiceProvider, Task> Handler { get; } = handler;
+    public string EventType { get; } = eventType;
+}

src/HopFrame.Core/Events/IEventEmitter.cs

@@ -0,0 +1,14 @@
+namespace HopFrame.Core.Events;
+
+public interface IEventEmitter {
+    
+    Guid RegisterEventHandler(string @event, Func<object, IServiceProvider, Task> handler);
+    
+    bool RemoveEventHandler(Guid id);
+    
+    Task DispatchEvent(string @event, object argument = null!);
+
+    void RemoveAllEventHandlers(string @event);
+    void RemoveAllEventHandlers();
+
+}

src/HopFrame.Core/ServiceCollectionExtensions.cs

@@ -1,4 +1,5 @@
-using HopFrame.Core.Services;
+using HopFrame.Core.Events;
+using HopFrame.Core.Services;
 using HopFrame.Core.Services.Implementations;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
@@ -15,6 +16,7 @@ public static class ServiceCollectionExtensions {
     public static IServiceCollection AddHopFrameServices(this IServiceCollection services) {
         services.AddScoped<IContextExplorer, ContextExplorer>();
         services.TryAddScoped<IHopFrameAuthHandler, DefaultAuthHandler>();
+        services.TryAddSingleton<IEventEmitter, EventEmitter>();
         return services;
     }
     

src/HopFrame.Core/Services/Implementations/EventEmitter.cs

@@ -0,0 +1,39 @@
+using HopFrame.Core.Config;
+using HopFrame.Core.Events;
+
+namespace HopFrame.Core.Services.Implementations;
+
+internal sealed class EventEmitter(IServiceProvider provider, HopFrameConfig config) : IEventEmitter {
+    
+    public Guid RegisterEventHandler(string @event, Func<object, IServiceProvider, Task> handler) {
+        var handlerStore = new HopEventHandler(@event, handler);
+        config.Handlers.Add(handlerStore);
+        return handlerStore.Id;
+    }
+    
+    public bool RemoveEventHandler(Guid id) {
+        var count = config.Handlers.RemoveAll(handler => handler.Id == id);
+        return count > 0;
+    }
+    
+    public async Task DispatchEvent(string @event, object argument = null!) {
+        var handlers = config.Handlers.Where(handler => handler.EventType == @event);
+        var tasks = new List<Task>();
+        
+        foreach (var handler in handlers) {
+            var task = handler.Handler.Invoke(argument, provider);
+            tasks.Add(task);
+        }
+
+        await Task.WhenAll(tasks);
+    }
+    
+    public void RemoveAllEventHandlers(string @event) {
+        config.Handlers.RemoveAll(handler => handler.EventType == @event);
+    }
+    
+    public void RemoveAllEventHandlers() {
+        config.Handlers.Clear();
+    }
+    
+}