package mysql

import (
	"database/sql"
	"main/models"
	"main/utils"
)

func GetAllStudentInfo() (back *[]models.User, err error) {
	sqlStr := `select
		user_id, user_name, user_gender, user_score
		from user 
		ORDER BY user_score ASC`
	back = new([]models.User)
	if err = db.Select(back, sqlStr); err != nil {
		if err == sql.ErrNoRows {
			err = utils.ErrorStuInfoEmpty
			return
		}
		return
	}
	return
}

func GetOneRandomStudentInfo() (back *models.User, err error) {
	sqlStr := `select
		user_id, user_name, user_gender, user_score
		from user 
		ORDER BY RAND() LIMIT 1`
	back = new(models.User)
	if err = db.Get(back, sqlStr); err != nil {
		if err == sql.ErrNoRows {
			err = utils.ErrorStuInfoEmpty
			return
		}
		return
	}
	return
}

func GetTargetStudentInfo(user_id int64) (back *models.User, err error) {
	sqlStr := `select
		user_id, user_name, user_gender, user_score
		from user 
		where user_id = ?`
	back = new(models.User)
	if err = db.Get(back, sqlStr, user_id); err != nil {
		if err == sql.ErrNoRows {
			err = utils.ErrorStuInfoEmpty
			return
		}
		return
	}
	return
}

func ChangeStuScore(user *models.UserScore) (err error) {
	sqlStr := `update user set
	user_score = ?
	where user_id=?`
	r, err := db.Exec(sqlStr, user.User_score, user.User_id)
	if n, err := r.RowsAffected(); err != nil || n == 0 {
		return utils.ErrorInvalidStuId
	}
	return
}