feat(oauth): add OAuth session caching to prevent multiple authentication attempts

ts/bunq.classes.account.ts

@@ -2,6 +2,7 @@ import * as plugins from './bunq.plugins.js';
 import { BunqApiContext } from './bunq.classes.apicontext.js';
 import { BunqMonetaryAccount } from './bunq.classes.monetaryaccount.js';
 import { BunqUser } from './bunq.classes.user.js';
+import { BunqApiError } from './bunq.classes.httpclient.js';
 import type { IBunqSessionServerResponse } from './bunq.interfaces.js';
 
 export interface IBunqConstructorOptions {
@@ -16,6 +17,9 @@ export interface IBunqConstructorOptions {
  * the main bunq account
  */
 export class BunqAccount {
+  // Static cache for OAuth token sessions to prevent multiple authentication attempts
+  private static oauthSessionCache = new Map<string, BunqApiContext>();
+  
   public options: IBunqConstructorOptions;
   public apiContext: BunqApiContext;
   public userId: number;
@@ -31,17 +35,60 @@ export class BunqAccount {
    * Initialize the bunq account
    */
   public async init() {
-    // Create API context
-    this.apiContext = new BunqApiContext({
-      apiKey: this.options.apiKey,
-      environment: this.options.environment,
-      deviceDescription: this.options.deviceName,
-      permittedIps: this.options.permittedIps,
-      isOAuthToken: this.options.isOAuthToken
-    });
+    // For OAuth tokens, check if we already have a cached session
+    if (this.options.isOAuthToken) {
+      const cacheKey = `${this.options.apiKey}_${this.options.environment}`;
+      const cachedContext = BunqAccount.oauthSessionCache.get(cacheKey);
+      
+      if (cachedContext && cachedContext.hasValidSession()) {
+        // Reuse existing session
+        this.apiContext = cachedContext;
+        console.log('Reusing existing OAuth session from cache');
+      } else {
+        // Create new context and cache it
+        this.apiContext = new BunqApiContext({
+          apiKey: this.options.apiKey,
+          environment: this.options.environment,
+          deviceDescription: this.options.deviceName,
+          permittedIps: this.options.permittedIps,
+          isOAuthToken: this.options.isOAuthToken
+        });
+        
+        try {
+          await this.apiContext.init();
+          // Cache the successfully initialized context
+          BunqAccount.oauthSessionCache.set(cacheKey, this.apiContext);
+        } catch (error) {
+          // Handle "Superfluous authentication" or "Authentication token already has a user session" errors
+          if (error instanceof BunqApiError) {
+            const errorMessages = error.errors.map(e => e.error_description).join(' ');
+            if (errorMessages.includes('Superfluous authentication') ||
+                errorMessages.includes('Authentication token already has a user session')) {
+              console.log('OAuth token already has an active session, attempting to reuse...');
+              // Try to use the token directly without creating new session
+              await this.apiContext.initWithExistingSession();
+              // Cache the context with existing session
+              BunqAccount.oauthSessionCache.set(cacheKey, this.apiContext);
+            } else {
+              throw error;
+            }
+          } else {
+            throw error;
+          }
+        }
+      }
+    } else {
+      // Regular API key flow
+      this.apiContext = new BunqApiContext({
+        apiKey: this.options.apiKey,
+        environment: this.options.environment,
+        deviceDescription: this.options.deviceName,
+        permittedIps: this.options.permittedIps,
+        isOAuthToken: this.options.isOAuthToken
+      });
 
-    // Initialize API context (handles installation, device registration, session)
-    await this.apiContext.init();
+      await this.apiContext.init();
+    }
 
     // Create user instance
     this.bunqUser = new BunqUser(this.apiContext);
@@ -160,4 +207,28 @@ export class BunqAccount {
       this.apiContext = null;
     }
   }
+
+  /**
+   * Clear the OAuth session cache
+   */
+  public static clearOAuthCache(): void {
+    BunqAccount.oauthSessionCache.clear();
+    console.log('OAuth session cache cleared');
+  }
+
+  /**
+   * Clear a specific OAuth token from the cache
+   */
+  public static clearOAuthCacheForToken(apiKey: string, environment: 'SANDBOX' | 'PRODUCTION'): void {
+    const cacheKey = `${apiKey}_${environment}`;
+    BunqAccount.oauthSessionCache.delete(cacheKey);
+    console.log(`OAuth session cache cleared for token in ${environment} environment`);
+  }
+
+  /**
+   * Get the current size of the OAuth cache
+   */
+  public static getOAuthCacheSize(): number {
+    return BunqAccount.oauthSessionCache.size;
+  }
 }

ts/bunq.classes.apicontext.ts

@@ -162,4 +162,40 @@ export class BunqApiContext {
   public getBaseUrl(): string {
     return this.context.baseUrl;
   }
+
+  /**
+   * Check if the context has a valid session
+   */
+  public hasValidSession(): boolean {
+    return this.session && this.session.isSessionValid();
+  }
+
+  /**
+   * Initialize with existing OAuth session (skip installation/device/session creation)
+   */
+  public async initWithExistingSession(): Promise<void> {
+    // For OAuth tokens that already have a session, we just need to:
+    // 1. Use the OAuth token as the session token
+    // 2. Set OAuth mode for proper expiry handling
+    
+    this.context.sessionToken = this.options.apiKey;
+    
+    // Create session instance with existing token
+    this.session = new BunqSession(this.crypto, this.context);
+    this.session.setOAuthMode(true);
+    
+    // Try to get user info to validate the session
+    try {
+      // This will test if the session is valid
+      const testClient = this.session.getHttpClient();
+      const response = await testClient.get('/v1/user');
+      
+      if (response && response.Response) {
+        console.log('Successfully reused existing OAuth session');
+        await this.saveContext();
+      }
+    } catch (error) {
+      throw new Error(`Failed to reuse OAuth session: ${error.message}`);
+    }
+  }
 }