-- ============================================================================
-- 真退款链路：退款单状态与金额落库（幂等，可重复执行）
--
-- 本迁移与 internal/logic/migrate.go 的 migrateColumns() 内容一致：
-- 服务端启动时 Migrate() 会自动加列（项目约定：升级只需重启服务）。
-- 本文件供运维在无法重启 / 需要手工核对时使用。
--
-- 新增列：
--   member_orders.refund_no           商户退款单号（唯一；失败重发换新号）
--   member_orders.refund_status       退款状态：0未退款 1退款中 2退款成功 3退款失败
--   member_orders.refund_amount       退款金额（分，全额退款 = paid_price_cents）
--   member_orders.refund_reason       退款原因（后台登记，iOS/手工退款必填）
--   member_orders.refund_finished_at  退款确认完成时间（回调 / 查单轮询 / 手工登记）
-- ============================================================================

SET @db := DATABASE();

SET @sql := (
  SELECT IF(COUNT(*) = 0,
    'ALTER TABLE `member_orders` ADD COLUMN `refund_no` varchar(40) NOT NULL DEFAULT '''' COMMENT ''商户退款单号''',
    'SELECT ''member_orders.refund_no already exists'' AS msg')
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = @db AND TABLE_NAME = 'member_orders' AND COLUMN_NAME = 'refund_no'
);
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

SET @sql := (
  SELECT IF(COUNT(*) = 0,
    'ALTER TABLE `member_orders` ADD COLUMN `refund_status` tinyint NOT NULL DEFAULT 0 COMMENT ''退款状态：0未退款 1退款中 2退款成功 3退款失败''',
    'SELECT ''member_orders.refund_status already exists'' AS msg')
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = @db AND TABLE_NAME = 'member_orders' AND COLUMN_NAME = 'refund_status'
);
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

SET @sql := (
  SELECT IF(COUNT(*) = 0,
    'ALTER TABLE `member_orders` ADD COLUMN `refund_amount` bigint NOT NULL DEFAULT 0 COMMENT ''退款金额（分）''',
    'SELECT ''member_orders.refund_amount already exists'' AS msg')
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = @db AND TABLE_NAME = 'member_orders' AND COLUMN_NAME = 'refund_amount'
);
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

SET @sql := (
  SELECT IF(COUNT(*) = 0,
    'ALTER TABLE `member_orders` ADD COLUMN `refund_reason` varchar(255) NOT NULL DEFAULT '''' COMMENT ''退款原因''',
    'SELECT ''member_orders.refund_reason already exists'' AS msg')
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = @db AND TABLE_NAME = 'member_orders' AND COLUMN_NAME = 'refund_reason'
);
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;

SET @sql := (
  SELECT IF(COUNT(*) = 0,
    'ALTER TABLE `member_orders` ADD COLUMN `refund_finished_at` datetime DEFAULT NULL COMMENT ''退款确认完成时间''',
    'SELECT ''member_orders.refund_finished_at already exists'' AS msg')
  FROM information_schema.COLUMNS
  WHERE TABLE_SCHEMA = @db AND TABLE_NAME = 'member_orders' AND COLUMN_NAME = 'refund_finished_at'
);
PREPARE stmt FROM @sql; EXECUTE stmt; DEALLOCATE PREPARE stmt;