// Leer datos de la base de datos
let db = Firestore.firestore()
db.collection("users").document(userId).getDocument { (document, error) in
if let document = document, document.exists {
let data = document.data()
let name = data?["name"] as? String ?? ""
let email = data?["email"] as? String ?? ""
print("Nombre: (name), Email: (email)")
} else {
print("El documento no existe")
}
}

// Consultar datos de la base de datos
let db = Firestore.firestore()
db.collection("users").whereField("name", isEqualTo: "Juan Pérez").getDocuments { (querySnapshot, error) in
  if let error = error {
         print("Error al consultar los datos: (error.localizedDescription)")
      return
}
guard let documents = querySnapshot?.documents else {
      print("No se encontraron documentos")
      return
}
for document in documents {
let data = document.data()
let name = data["name"] as? String ?? ""
let email = data["email"] as? String ?? ""
     print("Nombre: (name), Email: (email)")
  }
}

// Escuchar cambios en la base de datos
let db = Firestore.firestore()
db.collection("users").document(userId).addSnapshotListener { (document, error) in
  if let document = document, document.exists {
let data = document.data()
let name = data?["name"] as? String ?? ""
let email = data?["email"] as? String ?? ""
      print("Nombre: (name), Email: (email)")
} else {
     print("El documento no existe")
}
}