implement extensions framework

src/app.ts

@@ -1,6 +1,7 @@
 import bolt from '@slack/bolt'; 
 import { PrismaClient } from '@prisma/client';
 import { IntervalManager } from './utils/intervalManager.js';
+import { ExtensionsManager } from './utils/extensions.js';
 import { Environment, Constants } from './constants.js';
 
 export const app = new bolt.App({
@@ -23,4 +24,6 @@ export const prisma = new PrismaClient();
 export const minuteInterval = new IntervalManager(Constants.MIN_MS);
 export const hourInterval = new IntervalManager(Constants.HOUR_MS);
 
-hourInterval.setDelay(Constants.HOUR_MS - Date.now() % Constants.HOUR_MS);
+hourInterval.setDelay(Constants.HOUR_MS - Date.now() % Constants.HOUR_MS);
+
+export const extensions = new ExtensionsManager();

src/subroutines/hackhour.ts

@@ -1,4 +1,4 @@
-import { app, prisma, minuteInterval, hourInterval } from '../app.js';
+import { app, prisma, minuteInterval, extensions } from '../app.js';
 import { Commands, Environment } from '../constants.js';
 
 import { Callbacks, Views, Actions } from '../views/hackhour.js';

src/utils/extensions.ts

@@ -0,0 +1,34 @@
+export type ExtensionArgs = {
+    slackId?: string,
+    sessionTs?: string,
+}
+
+export type Extension = {
+    onStart: ((args: ExtensionArgs) => void) | null,
+    onError: ((args: ExtensionArgs) => void) | null,    
+    userCreated: ((args: ExtensionArgs) => void) | null,
+    sessionStarted: ((args: ExtensionArgs) => void) | null,
+    sessionCancelled: ((args: ExtensionArgs) => void) | null,
+    sessionCompleted: ((args: ExtensionArgs) => void) | null,
+}
+
+export type ExtensionFunc = keyof Extension;
+
+class ExtensionsManagerInner {
+    private extensions: Extension[] = [];
+
+    public attach(extension: Extension): void {
+        this.extensions.push(extension);
+    }
+
+    public getExtensions(): Extension[] {
+        return this.extensions;
+    }
+}
+
+export const ExtensionsManager = new Proxy(new ExtensionsManagerInner(), 
+{
+    get: function(target, prop, receiver) {
+        return target.getExtensions();
+    }
+});