ALTER TABLE `students`
  DROP INDEX `national_id`,
  DROP INDEX `idx_students_national_id`,
  MODIFY `national_id` TEXT NOT NULL,
  ADD COLUMN `national_id_hash` CHAR(64) NULL AFTER `national_id`,
  ADD INDEX `idx_students_national_id_hash` (`national_id_hash`),
  MODIFY `readiness_score` DECIMAL(5,2) NOT NULL DEFAULT 0.00;

ALTER TABLE `school_rosters`
  DROP INDEX `idx_school_national_id`,
  DROP INDEX `idx_roster_national_id`,
  MODIFY `national_id` TEXT NOT NULL,
  ADD COLUMN `national_id_hash` CHAR(64) NULL AFTER `national_id`,
  ADD INDEX `idx_roster_national_id_hash` (`national_id_hash`);

-- Backfill national_id_hash from the application before making these columns
-- NOT NULL and UNIQUE. The encryption key must remain the production key.

CREATE TABLE IF NOT EXISTS `staff_accounts` (
  `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `uuid` CHAR(36) NOT NULL UNIQUE,
  `identity_id` BIGINT UNSIGNED NOT NULL,
  `full_name` VARCHAR(255) NOT NULL,
  `role` ENUM('school_admin', 'directorate_admin', 'supervisor', 'super_admin') NOT NULL,
  `school_id` BIGINT UNSIGNED DEFAULT NULL,
  `directorate_id` BIGINT UNSIGNED DEFAULT NULL,
  `status` ENUM('active', 'suspended') NOT NULL DEFAULT 'active',
  `created_at` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP,
  `updated_at` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `idx_staff_identity_role` (`identity_id`, `role`),
  KEY `idx_staff_school` (`school_id`),
  KEY `idx_staff_directorate` (`directorate_id`),
  CONSTRAINT `fk_staff_identity` FOREIGN KEY (`identity_id`) REFERENCES `auth_identities` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_staff_school` FOREIGN KEY (`school_id`) REFERENCES `schools` (`id`) ON DELETE SET NULL,
  CONSTRAINT `fk_staff_directorate` FOREIGN KEY (`directorate_id`) REFERENCES `directorates` (`id`) ON DELETE SET NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE IF NOT EXISTS `guardian_link_requests` (
  `id` BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  `uuid` CHAR(36) NOT NULL UNIQUE,
  `guardian_id` BIGINT UNSIGNED NOT NULL,
  `student_id` BIGINT UNSIGNED NOT NULL,
  `relationship_type` ENUM('father', 'mother', 'brother', 'guardian') NOT NULL DEFAULT 'guardian',
  `status` ENUM('pending', 'approved', 'rejected', 'cancelled') NOT NULL DEFAULT 'pending',
  `reviewed_at` TIMESTAMP NULL DEFAULT NULL,
  `created_at` TIMESTAMP NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
  UNIQUE KEY `uq_guardian_link_pending` (`guardian_id`, `student_id`, `status`),
  CONSTRAINT `fk_link_request_guardian` FOREIGN KEY (`guardian_id`) REFERENCES `guardians` (`id`) ON DELETE CASCADE,
  CONSTRAINT `fk_link_request_student` FOREIGN KEY (`student_id`) REFERENCES `students` (`id`) ON DELETE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;