摘要：實現功能抽獎需求后臺控制每種中獎的概率控制獎品數量備注獎品是以優惠券的形式發放給用戶進行兌換，需要考慮到優惠券數量問題以此為例九宮格一個開始，一個謝謝參與，后臺設置七個獎品獲取每個獎品中獎概率，及該獎品的我是以的總數概率來計算的獲取獎品及該

實現功能：抽獎

需求：后臺控制每種中獎的概率、控制獎品數量

備注：獎品是以優惠券的形式發放給用戶進行兌換，需要考慮到優惠券數量問題

以此為例：
九宮格一個開始btn，一個謝謝參與，后臺設置七個獎品

1.獲取每個獎品中獎概率，及該獎品的id,我是以1000的總數概率來計算的

/**獲取獎品及該獎品的中獎概率
 * Created by PhpStorm.
 * User: Alisa
 * Date: 2018/12/6
 * Time: 18:02
 * @param $extract_prize_id
 * @return mixed
 */
public function user_prize ($extract_prize_id)
{
    $prize = (new Query())
        ->from(["p"=>Prize::tableName()])
        ->leftJoin(["c"=>Coupon::tableName()],"c.id = p.coupon_id")
        ->select("p.prize_pro,p.id")
        ->where(["p.extract_prize_id"=>$extract_prize_id])
        ->andWhere([">","c.surplus_num",0])
        ->all();
    $sum = (new Query())
        ->from(["p"=>Prize::tableName()])
        ->leftJoin(["c"=>Coupon::tableName()],"c.id = p.coupon_id")
        ->where(["p.extract_prize_id"=>$extract_prize_id])
        ->andWhere([">","c.surplus_num",0])
        ->sum("p.prize_pro");

    $count = count($prize);
    foreach ($prize as $k=>$v){
        $list[$k] = $v;
    }
    $list[$count] = [
        "prize_pro"=>Math::sub(1000,$sum,0),
        "id"=>0
    ];
    $res = $this->get_rand($list);
    return $list[$res]["id"];
}

2.進行抽獎計算，返回中獎的獎品id，id是0的話，表示謝謝參與

/**抽獎計算
 * Created by PhpStorm.
 * User: Alisa
 * Date: 2018/12/6
 * Time: 18:10
 * @param $proArr
 * @return int|string
 */
public function get_rand($proArr){
    $result = "";
    foreach ($proArr as $key => $val) {
        $arr[$key] = $val["prize_pro"];
    }
    // 概率數組的總概率
    $proSum = 1000;
    // 概率數組循環
    foreach ($arr as $k => $v) {
        $randNum = mt_rand(1, $proSum);
        if ($randNum <= $v) {
            $result = $k;
            break;
        } else {
            $proSum -= $v;
        }
    }
    return $result;
}

3.進行后續邏輯處理，判斷優惠券剩余數量并減去、減去用戶抽獎冊數、增加用戶抽獎記錄、中獎的話優惠券到賬

/**用戶抽獎
 * @param $userId
 * @param $extract_prize_id
 * @return array|bool
 * @throws yiidbException
 */
 public function extractPrize($userId,$extract_prize_id)
{
    $prize_id = $this->user_prize($extract_prize_id);
    $coupon_id = 0;
    $prize_name = "謝謝參與";
    $prize_url = "";
    if($prize_id){
        $coupon = (new Query())
            ->select("c.id,c.name,c.rule,c.validity,c.surplus_num")
            ->from(["pr"=>Prize::tableName()])
            ->leftJoin(["c"=>Coupon::tableName()],"c.id = pr.coupon_id")
            ->where(["pr.id"=>$prize_id])
            ->one();
        if($coupon["surplus_num"] > 0){
            $coupon_id = $coupon["id"];
            $prize_name = $coupon["name"];
            $url = (new Query())
                ->select("pi.url")
                ->from(["pr"=>Prize::tableName()])
                ->leftJoin(["pi"=>Picture::tableName()],"pi.id = pr.img_id")
                ->where(["pr.id"=>$prize_id])
                ->one();
            $prize_url = $url["url"];
        }
    }
    $trans = Yii::$app->db->beginTransaction();
    try{
        $model = new ExtractPrizeRecord();
        $model->prize_id = $prize_id;
        $model->coupon_id = $coupon_id;
        $model->prize_name = $prize_name;
        $model->user_id = $userId;
        $model->type = $extract_prize_id;
        $model->create_at = time();
        $res_ex = $model->save();
        if ( $res_ex ) {
            //減去用戶抽獎次數
            Yii::$app->db->createCommand("update users set $str = $str - 1 where $str > 0 and user_id = :user_id",
                [
                    ":user_id" => $userId,
                ]
            )->execute();
            if(($coupon_id > 0) && ($coupon["surplus_num"] > 0)){
                //減去優惠券剩余數量
                Yii::$app->db->createCommand("update coupon set surplus_num = surplus_num -1 where id = :coupon_id and surplus_num > 0",
                    [
                        ":coupon_id" => $coupon_id,
                    ]
                )->execute();
                $myModel = new MyCoupon();
                $myModel->user_id = $userId;
                $myModel->name = $coupon["name"];
                $myModel->rule = $coupon["rule"];
                $myModel->coupon_id = $coupon_id;
                $myModel->create_at = time();
                $myModel->update_at = time();
                $myModel->start_at = time();
                $myModel->end_at = time() + $coupon["validity"]* 86400;
                $myModel->re_code = StringTools::randString(10);
                $myModel->coupon_number = date("YmdHis") . rand(10000000,99999999);
                $myModel->save();
            }
        } else {
            return false;
        }
        $trans ->commit();
        return ["prize_name"=>$prize_name,"prize_url"=>$prize_url];
    }catch (Throwable $t) {
        $trans->rollBack();
        return false;
    }
}

如果你覺得這篇文章還不錯，下角點個贊，是對我開源最大的鼓勵O(∩_∩)O