-- 文件存储分层改造：yz_system_files 新增归属与存储字段
-- 对应计划文档：go/docs/文件存储分层改造计划.md  S1
--
-- 幂等脚本：用存储过程逐项判断，已存在的列/索引自动跳过，可反复执行，不会报
--           1060 Duplicate column / 1061 Duplicate key。
--
-- 背景：md5 在部分历史库中是 TEXT 类型，MySQL 不允许对 TEXT/BLOB 建整列索引，
--       因此 idx_file_dedup 使用前缀长度 md5(32)（MD5 十六进制串固定 32 字符，等价全值）。

DROP PROCEDURE IF EXISTS `yz_alter_system_files_storage`;

DELIMITER $$

CREATE PROCEDURE `yz_alter_system_files_storage`()
BEGIN
  DECLARE v_db VARCHAR(64);
  SET v_db = DATABASE();

  -- 1. 字段：source
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.COLUMNS
    WHERE TABLE_SCHEMA = v_db AND TABLE_NAME = 'yz_system_files' AND COLUMN_NAME = 'source'
  ) THEN
    ALTER TABLE `yz_system_files`
      ADD COLUMN `source` varchar(16) NOT NULL DEFAULT 'backend'
      COMMENT '来源端: backend-租户后台 platform-平台端';
  END IF;

  -- 2. 字段：scope
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.COLUMNS
    WHERE TABLE_SCHEMA = v_db AND TABLE_NAME = 'yz_system_files' AND COLUMN_NAME = 'scope'
  ) THEN
    ALTER TABLE `yz_system_files`
      ADD COLUMN `scope` varchar(16) NOT NULL DEFAULT 'tenant'
      COMMENT '归属: tenant-租户共享 user-用户个人';
  END IF;

  -- 3. 字段：storage
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.COLUMNS
    WHERE TABLE_SCHEMA = v_db AND TABLE_NAME = 'yz_system_files' AND COLUMN_NAME = 'storage'
  ) THEN
    ALTER TABLE `yz_system_files`
      ADD COLUMN `storage` varchar(16) NOT NULL DEFAULT ''
      COMMENT '存储类型: local/qiniu（冗余，便于迁移与排查）';
  END IF;

  -- 4. 字段：object_key
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.COLUMNS
    WHERE TABLE_SCHEMA = v_db AND TABLE_NAME = 'yz_system_files' AND COLUMN_NAME = 'object_key'
  ) THEN
    ALTER TABLE `yz_system_files`
      ADD COLUMN `object_key` varchar(512) NOT NULL DEFAULT ''
      COMMENT '存储相对路径(不含域名)，用于迁移与精确删除';
  END IF;

  -- 5. 索引：查重（source + scope + tid + tuid + md5 前缀）
  --    不加 UNIQUE：软删(delete_time)与并发上传下唯一索引会直接报错，去重在代码层完成
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.STATISTICS
    WHERE TABLE_SCHEMA = v_db AND TABLE_NAME = 'yz_system_files' AND INDEX_NAME = 'idx_file_dedup'
  ) THEN
    ALTER TABLE `yz_system_files`
      ADD KEY `idx_file_dedup` (`source`, `scope`, `tid`, `tuid`, `md5`(32));
  END IF;

  -- 6. 索引：归属列表过滤
  IF NOT EXISTS (
    SELECT 1 FROM information_schema.STATISTICS
    WHERE TABLE_SCHEMA = v_db AND TABLE_NAME = 'yz_system_files' AND INDEX_NAME = 'idx_file_owner'
  ) THEN
    ALTER TABLE `yz_system_files`
      ADD KEY `idx_file_owner` (`source`, `tid`, `scope`, `tuid`, `delete_time`);
  END IF;
END$$

DELIMITER ;

CALL `yz_alter_system_files_storage`();
DROP PROCEDURE IF EXISTS `yz_alter_system_files_storage`;

-- 7. 老数据初始化：迁移脚本执行前先打底，避免 source/scope 为空导致查询遗漏
UPDATE `yz_system_files` SET `source` = 'backend' WHERE `source` = '' OR `source` IS NULL;
UPDATE `yz_system_files` SET `scope`  = 'tenant'  WHERE `scope`  = '' OR `scope`  IS NULL;

-- 8. 校验（应看到 4 个字段 + 2 个索引）
-- SHOW COLUMNS FROM yz_system_files LIKE 'source';
-- SHOW COLUMNS FROM yz_system_files LIKE 'scope';
-- SHOW COLUMNS FROM yz_system_files LIKE 'storage';
-- SHOW COLUMNS FROM yz_system_files LIKE 'object_key';
-- SHOW INDEX FROM yz_system_files WHERE Key_name IN ('idx_file_dedup','idx_file_owner');