package business

import "gorm.io/gorm"

// 区服汇总按创角时间读取原始记录；旧表只有 play_time 索引，导致每日创角扫描全表。
func migrateServerReportIndex(db *gorm.DB) error {
	if db.Dialector.Name() != "mysql" || !db.Migrator().HasTable("tab_user_play_info") {
		return nil
	}
	var existing int64
	if err := db.Raw("SELECT COUNT(*) FROM information_schema.statistics WHERE table_schema=DATABASE() AND table_name='tab_user_play_info' AND column_name='create_time' AND seq_in_index=1").Scan(&existing).Error; err != nil {
		return err
	}
	if existing > 0 {
		return nil
	}
	return db.Exec("ALTER TABLE tab_user_play_info ADD INDEX idx_sw_play_create_time(create_time), ALGORITHM=INPLACE, LOCK=NONE").Error
}