From 4901e9d3efad113056f6b16a71b537a64125bf99 Mon Sep 17 00:00:00 2001
From: Pierre HUBERT <pierre.git@communiquons.org>
Date: Mon, 30 Mar 2020 14:20:33 +0200
Subject: [PATCH] Create internal custom event manager

---
 src/helpers/AccountHelper.ts |  8 +++++
 src/helpers/EventsHelper.ts  | 69 ++++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 src/helpers/EventsHelper.ts

diff --git a/src/helpers/AccountHelper.ts b/src/helpers/AccountHelper.ts
index 3c07ce0..06cd159 100644
--- a/src/helpers/AccountHelper.ts
+++ b/src/helpers/AccountHelper.ts
@@ -18,6 +18,7 @@ import { GroupsHelper } from "./GroupsHelper";
 import { NotificationsHelper } from "./NotificationsHelper";
 import { AccountImageHelper } from "./AccountImageHelper";
 import { BackgroundImageHelper } from "./BackgroundImageHelper";
+import { EventsHelper } from "./EventsHelper";
 
 /**
  * Account helper
@@ -147,6 +148,13 @@ export class AccountHelper {
 	 * @param userID Target user ID
 	 */
 	public static async DestroyUserTokens(client: APIClient, userID: number) {
+
+		// Push the event
+		EventsHelper.Emit("destroyed_login_tokens", {
+			client: client,
+			userID: userID
+		});
+
 		return DatabaseHelper.DeleteRows(USERS_TOKENS_TABLE, {
 			service_id: client.id,
 			user_id: userID
diff --git a/src/helpers/EventsHelper.ts b/src/helpers/EventsHelper.ts
new file mode 100644
index 0000000..528ceb0
--- /dev/null
+++ b/src/helpers/EventsHelper.ts
@@ -0,0 +1,69 @@
+import { EventEmitter } from "events";
+import { APIClient } from "../entities/APIClient";
+
+/**
+ * Events manager
+ * 
+ * @author Pierre Hubert
+ */
+
+// When a user sign out
+export interface DestroyedLoginTokensEvent {
+	userID: number,
+	client: APIClient
+}
+
+/**
+ * Global map of all possible events
+ */
+export interface EventsMap {
+	"destroyed_login_tokens": DestroyedLoginTokensEvent
+}
+
+export class EventsHelper {
+
+	/**
+	 * The list of events
+	 */
+	private static EventsList: Map<keyof EventsMap, Array<(ev: any) => void | Promise<void>>> = new Map()
+
+	/**
+	 * Listen to a new event
+	 * 
+	 * @param name The name of the event to listen to
+	 * @param listener Target listener
+	 */
+	public static Listen<K extends keyof EventsMap>(name: K, listener: (ev: EventsMap[K]) => void | Promise<void>) {
+		if(!this.EventsList[<any>name])
+			this.EventsList[<any>(name)] = [];
+
+		this.EventsList[<any>(name)].push(listener);
+		
+	}
+
+	/**
+	 * Push a new event
+	 * 
+	 * Note : It is not mandatory to listen to this method, as
+	 * we will try / catch all the events
+	 * 
+	 * @param name The name of the event
+	 * @param args Argumens to pass to the event
+	 */
+	public static async Emit<K extends keyof EventsMap>(name: K, args: EventsMap[K]) {
+		
+		if(!this.EventsList[<any>name])
+			return;
+
+		for(const entry of this.EventsList[<any>name]) {
+			try {
+				await entry(args);
+			}
+			catch(e) {
+				console.error("An error occured while propagating an event ("+name+")!", e, args);
+			}
+		}
+	}
+
+	
+}
\ No newline at end of file