-- AIHR 案例原始音频字段迁移（MySQL 8.x）
-- 仅补齐旧库缺失的媒体留痕字段，不写入业务数据；可重复执行。

SET @aihr_case_table_exists := (
  SELECT COUNT(*)
  FROM information_schema.TABLES
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'aihr_case_record'
);

SET @aihr_case_media_oss_exists := (
  SELECT COUNT(*)
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'aihr_case_record'
    AND COLUMN_NAME = 'media_oss_id'
);
SET @aihr_case_media_oss_ddl := IF(
  @aihr_case_table_exists = 1 AND @aihr_case_media_oss_exists = 0,
  'ALTER TABLE aihr_case_record ADD COLUMN `media_oss_id` bigint DEFAULT NULL COMMENT ''原始音频OSS文件ID'' AFTER `summary`',
  'SELECT 1'
);
PREPARE aihr_case_media_oss_stmt FROM @aihr_case_media_oss_ddl;
EXECUTE aihr_case_media_oss_stmt;
DEALLOCATE PREPARE aihr_case_media_oss_stmt;

SET @aihr_case_media_url_exists := (
  SELECT COUNT(*)
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = DATABASE()
    AND TABLE_NAME = 'aihr_case_record'
    AND COLUMN_NAME = 'media_url'
);
SET @aihr_case_media_url_ddl := IF(
  @aihr_case_table_exists = 1 AND @aihr_case_media_url_exists = 0,
  'ALTER TABLE aihr_case_record ADD COLUMN `media_url` varchar(500) DEFAULT NULL COMMENT ''原始音频访问地址'' AFTER `media_oss_id`',
  'SELECT 1'
);
PREPARE aihr_case_media_url_stmt FROM @aihr_case_media_url_ddl;
EXECUTE aihr_case_media_url_stmt;
DEALLOCATE PREPARE aihr_case_media_url_stmt;