feat: Implement slack authentication

packages/backend/src/apps/slack/authentication.ts

@@ -0,0 +1,39 @@
+import type { IAuthentication, IApp, IJSONObject } from '@automatisch/types';
+import { WebClient } from '@slack/web-api';
+
+export default class Authentication implements IAuthentication {
+  appData: IApp;
+  connectionData: IJSONObject;
+  client: WebClient;
+
+  constructor(appData: IApp, connectionData: IJSONObject) {
+    this.client = new WebClient();
+
+    this.connectionData = connectionData;
+    this.appData = appData;
+  }
+
+  async verifyCredentials() {
+    const { bot_id: botId, user: screenName } = await this.client.auth.test({
+      token: this.connectionData.accessToken as string,
+    });
+
+    return {
+      botId,
+      screenName,
+      token: this.connectionData.accessToken,
+    };
+  }
+
+  async isStillVerified() {
+    try {
+      await this.client.auth.test({
+        token: this.connectionData.accessToken as string,
+      });
+
+      return true;
+    } catch (error) {
+      return false;
+    }
+  }
+}