Add generación y expiración de tokens de sesión

mvp/b2c/src/lib/auth/tokens.ts

@@ -0,0 +1,19 @@
+import { randomBytes, createHash } from 'node:crypto';
+
+export const SESSION_TTL_MS = 30 * 24 * 60 * 60 * 1000; // 30 días
+
+export function generateSessionToken(): string {
+  return randomBytes(32).toString('hex');
+}
+
+export function hashSessionToken(token: string): string {
+  return createHash('sha256').update(token).digest('hex');
+}
+
+export function isSessionExpired(expiresAt: Date, now: Date = new Date()): boolean {
+  return expiresAt.getTime() <= now.getTime();
+}
+
+export function sessionExpiry(now: Date = new Date()): Date {
+  return new Date(now.getTime() + SESSION_TTL_MS);
+}

mvp/b2c/tests/auth/tokens.test.ts

@@ -0,0 +1,34 @@
+import { describe, it, expect } from 'vitest';
+import {
+  generateSessionToken,
+  hashSessionToken,
+  isSessionExpired,
+  sessionExpiry,
+  SESSION_TTL_MS,
+} from '@/lib/auth/tokens';
+
+describe('tokens', () => {
+  it('genera tokens distintos en hex de 64 chars', () => {
+    const a = generateSessionToken();
+    const b = generateSessionToken();
+    expect(a).toMatch(/^[0-9a-f]{64}$/);
+    expect(a).not.toBe(b);
+  });
+
+  it('hashea el token de forma determinista y distinta al token', () => {
+    const t = generateSessionToken();
+    expect(hashSessionToken(t)).toBe(hashSessionToken(t));
+    expect(hashSessionToken(t)).not.toBe(t);
+  });
+
+  it('marca expirada una sesión pasada y válida una futura', () => {
+    const now = new Date('2026-05-30T12:00:00Z');
+    expect(isSessionExpired(new Date('2026-05-29T12:00:00Z'), now)).toBe(true);
+    expect(isSessionExpired(new Date('2026-05-31T12:00:00Z'), now)).toBe(false);
+  });
+
+  it('sessionExpiry suma el TTL al instante dado', () => {
+    const now = new Date('2026-05-30T12:00:00Z');
+    expect(sessionExpiry(now).getTime()).toBe(now.getTime() + SESSION_TTL_MS);
+  });
+});