Adds Event system and automatic messages

source/Events/EventHandler.ts

@@ -0,0 +1,48 @@
+import cron from "node-cron";
+import {Nullable} from "../types/Nullable";
+import {Class, ClassNamed} from "../types/Class";  
+
+export type EventConfiguration = {
+  name: string, 
+  maxExecutions?: number,
+}
+
+export interface TimedEvent {
+  configuration: EventConfiguration,
+  cronExpression: string,
+  execute: () => void
+}
+
+export class EventHandler {
+  private eventHandlers: Map<string, CallableFunction[]> = new Map();
+  
+  constructor() {
+  }
+  
+  public addHandler<T extends Class>(eventName: string, handler: (event: T) => void) {
+    if (!this.eventHandlers.has(eventName)) {
+      this.eventHandlers.set(eventName, []);
+    }
+    
+    this.eventHandlers.get(eventName)?.push(handler);
+  }
+  
+  public dispatch<T extends Class>(event: T) {
+    const eventName = event.constructor.name;
+    if (!this.eventHandlers.has(eventName)) {
+      return;
+    }
+    
+    this.eventHandlers.get(eventName)?.forEach((handler) => {
+      handler(event);
+    })
+  }
+  
+  public addTimed(event: TimedEvent) {
+    if (!cron.validate(event.cronExpression)) {
+      throw new Error(`Can't create event with name '${event.configuration.name}': Invalid cron expression.`)
+    }
+    
+    cron.schedule(event.cronExpression, event.execute.bind(event), event.configuration);
+  }
+}