-- Tareas recurrentes: recordatorios periodicos (ej. renovacion de licencias) con recordatorio
-- por correo N dias antes, a una hora configurable. Menu propio, independiente de Proyectos, pero
-- puede originarse promoviendo una tarea existente de un proyecto (project_id queda como
-- referencia/contexto, nunca obligatorio).
CREATE TABLE IF NOT EXISTS recurring_tasks (
  id INT AUTO_INCREMENT PRIMARY KEY,
  name VARCHAR(160) NOT NULL,
  description TEXT NULL,
  project_id INT NULL,
  responsible_user_id INT NULL,
  interval_unit ENUM('days','months','years') NOT NULL DEFAULT 'months',
  interval_value INT NOT NULL DEFAULT 1,
  next_due_date DATE NOT NULL,
  reminder_days_before INT NOT NULL DEFAULT 7,
  reminder_hour TINYINT NOT NULL DEFAULT 9,
  is_active TINYINT(1) NOT NULL DEFAULT 1,
  last_reminder_sent_at DATETIME NULL,
  created_by INT NOT NULL,
  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  CONSTRAINT fk_recurring_tasks_project FOREIGN KEY (project_id) REFERENCES projects(id) ON DELETE SET NULL,
  CONSTRAINT fk_recurring_tasks_responsible FOREIGN KEY (responsible_user_id) REFERENCES users(id) ON DELETE SET NULL,
  CONSTRAINT fk_recurring_tasks_created_by FOREIGN KEY (created_by) REFERENCES users(id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;