package service

import (
	"github.com/mhsanaei/3x-ui/v3/internal/database/model"

	"gorm.io/gorm"
)

// adjustGroupBaselinesForRemovedTraffic shifts group baselines down by the clients'
// current counters so per-group traffic totals survive a traffic reset or client delete (#5675).
// current counters so ListGroups totals survive a traffic reset or client delete (#5675).
func adjustGroupBaselinesForRemovedTraffic(tx *gorm.DB, emails []string) error {
	if len(emails) == 0 {
		return nil
	}
	type groupDelta struct {
		Name string
		Up   int64
		Down int64
	}
	totals := make(map[string]*groupDelta)
	for _, batch := range chunkStrings(emails, sqlInChunk) {
		var part []groupDelta
		if err := tx.Table("clients AS c").
			Select("c.group_name AS name, COALESCE(SUM(ct.up), 0) AS up, COALESCE(SUM(ct.down), 0) AS down").
			Joins("JOIN client_traffics ct ON ct.email = c.email").
			Where("c.group_name <> '' AND c.email IN ?", batch).
			Group("c.group_name").
			Scan(&part).Error; err != nil {
			return err
		}
		for i := range part {
			if agg, ok := totals[part[i].Name]; ok {
				agg.Up += part[i].Up
				agg.Down += part[i].Down
			} else {
				totals[part[i].Name] = &part[i]
			}
		}
	}
	for name, d := range totals {
		if d.Up == 0 && d.Down == 0 {
			continue
		}
		res := tx.Model(&model.ClientGroup{}).Where("name = ?", name).Updates(map[string]any{
			"reset_up":   gorm.Expr("reset_up - ?", d.Up),
			"reset_down": gorm.Expr("reset_down - ?", d.Down),
		})
		if res.Error != nil {
			return res.Error
		}
		if res.RowsAffected == 0 {
			if err := tx.Create(&model.ClientGroup{Name: name, ResetUp: -d.Up, ResetDown: -d.Down}).Error; err != nil {
				return err
			}
		}
	}
	return nil
}