Fix PKCE flow and clean up other flows

plugins/auth-oauth2/src/getAccessTokenIfNotExpired.ts

@@ -0,0 +1,19 @@
+import type { Context } from '@yaakapp/api';
+import type { AccessToken } from './store';
+import { getToken } from './store';
+
+export async function getAccessTokenIfNotExpired(
+  ctx: Context,
+  contextId: string,
+): Promise<AccessToken | null> {
+  const token = await getToken(ctx, contextId);
+  if (token == null || isTokenExpired(token)) {
+    return null;
+  }
+
+  return token;
+}
+
+export function isTokenExpired(token: AccessToken) {
+  return token.expiresAt && Date.now() > token.expiresAt;
+}