1 files changed, 140 insertions, 0 deletions
diff --git a/packages/core/src/utils/userAccountManager.ts b/packages/core/src/utils/userAccountManager.ts
new file mode 100644
index 00000000..28d3cef9
--- /dev/null
+++ b/packages/core/src/utils/userAccountManager.ts
@@ -0,0 +1,140 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import path from 'node:path';
+import { promises as fsp, readFileSync } from 'node:fs';
+import { Storage } from '../config/storage.js';
+
+interface UserAccounts {
+  active: string | null;
+  old: string[];
+}
+
+export class UserAccountManager {
+  private getGoogleAccountsCachePath(): string {
+    return Storage.getGoogleAccountsPath();
+  }
+
+  /**
+   * Parses and validates the string content of an accounts file.
+   * @param content The raw string content from the file.
+   * @returns A valid UserAccounts object.
+   */
+  private parseAndValidateAccounts(content: string): UserAccounts {
+    const defaultState = { active: null, old: [] };
+    if (!content.trim()) {
+      return defaultState;
+    }
+
+    const parsed = JSON.parse(content);
+
+    // Inlined validation logic
+    if (typeof parsed !== 'object' || parsed === null) {
+      console.log('Invalid accounts file schema, starting fresh.');
+      return defaultState;
+    }
+    const { active, old } = parsed as Partial<UserAccounts>;
+    const isValid =
+      (active === undefined || active === null || typeof active === 'string') &&
+      (old === undefined ||
+        (Array.isArray(old) && old.every((i) => typeof i === 'string')));
+
+    if (!isValid) {
+      console.log('Invalid accounts file schema, starting fresh.');
+      return defaultState;
+    }
+
+    return {
+      active: parsed.active ?? null,
+      old: parsed.old ?? [],
+    };
+  }
+
+  private readAccountsSync(filePath: string): UserAccounts {
+    const defaultState = { active: null, old: [] };
+    try {
+      const content = readFileSync(filePath, 'utf-8');
+      return this.parseAndValidateAccounts(content);
+    } catch (error) {
+      if (
+        error instanceof Error &&
+        'code' in error &&
+        error.code === 'ENOENT'
+      ) {
+        return defaultState;
+      }
+      console.log('Error during sync read of accounts, starting fresh.', error);
+      return defaultState;
+    }
+  }
+
+  private async readAccounts(filePath: string): Promise<UserAccounts> {
+    const defaultState = { active: null, old: [] };
+    try {
+      const content = await fsp.readFile(filePath, 'utf-8');
+      return this.parseAndValidateAccounts(content);
+    } catch (error) {
+      if (
+        error instanceof Error &&
+        'code' in error &&
+        error.code === 'ENOENT'
+      ) {
+        return defaultState;
+      }
+      console.log('Could not parse accounts file, starting fresh.', error);
+      return defaultState;
+    }
+  }
+
+  async cacheGoogleAccount(email: string): Promise<void> {
+    const filePath = this.getGoogleAccountsCachePath();
+    await fsp.mkdir(path.dirname(filePath), { recursive: true });
+
+    const accounts = await this.readAccounts(filePath);
+
+    if (accounts.active && accounts.active !== email) {
+      if (!accounts.old.includes(accounts.active)) {
+        accounts.old.push(accounts.active);
+      }
+    }
+
+    // If the new email was in the old list, remove it
+    accounts.old = accounts.old.filter((oldEmail) => oldEmail !== email);
+
+    accounts.active = email;
+    await fsp.writeFile(filePath, JSON.stringify(accounts, null, 2), 'utf-8');
+  }
+
+  getCachedGoogleAccount(): string | null {
+    const filePath = this.getGoogleAccountsCachePath();
+    const accounts = this.readAccountsSync(filePath);
+    return accounts.active;
+  }
+
+  getLifetimeGoogleAccounts(): number {
+    const filePath = this.getGoogleAccountsCachePath();
+    const accounts = this.readAccountsSync(filePath);
+    const allAccounts = new Set(accounts.old);
+    if (accounts.active) {
+      allAccounts.add(accounts.active);
+    }
+    return allAccounts.size;
+  }
+
+  async clearCachedGoogleAccount(): Promise<void> {
+    const filePath = this.getGoogleAccountsCachePath();
+    const accounts = await this.readAccounts(filePath);
+
+    if (accounts.active) {
+      if (!accounts.old.includes(accounts.active)) {
+        accounts.old.push(accounts.active);
+      }
+      accounts.active = null;
+    }
+
+    await fsp.writeFile(filePath, JSON.stringify(accounts, null, 2), 'utf-8');
+  }
+}