START TRANSACTION;

-- 1) Roles: parent -> student
ALTER TABLE users MODIFY role ENUM('admin','driver','student') NOT NULL;
UPDATE users SET role = 'student' WHERE role = 'parent';

-- 2) Student profile table (1:1 with users)
CREATE TABLE IF NOT EXISTS students (
  id INT AUTO_INCREMENT PRIMARY KEY,
  user_id INT NOT NULL UNIQUE,
  national_id VARCHAR(30) DEFAULT NULL,
  career VARCHAR(150) DEFAULT NULL,
  semester VARCHAR(50) DEFAULT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
  updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  CONSTRAINT fk_students_user FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
  INDEX idx_students_user_id (user_id),
  INDEX idx_students_national_id (national_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

COMMIT;