feat(xero): add xero integration

packages/backend/src/apps/xero/auth/generate-auth-url.ts

@@ -0,0 +1,22 @@
+import { IField, IGlobalVariable } from '@automatisch/types';
+import { URLSearchParams } from 'url';
+import authScope from '../common/auth-scope';
+
+export default async function generateAuthUrl($: IGlobalVariable) {
+  const oauthRedirectUrlField = $.app.auth.fields.find(
+    (field: IField) => field.key == 'oAuthRedirectUrl'
+  );
+  const redirectUri = oauthRedirectUrlField.value as string;
+  const searchParams = new URLSearchParams({
+    response_type: 'code',
+    client_id: $.auth.data.clientId as string,
+    scope: authScope.join(' '),
+    redirect_uri: redirectUri,
+  });
+
+  const url = `https://login.xero.com/identity/connect/authorize?${searchParams.toString()}`;
+
+  await $.auth.set({
+    url,
+  });
+}