php 積分抽獎活動（大轉盤）

以下是項目代碼(公眾號，使用積分進行抽獎活動)，只可做參考：

public function Sncode()
{
    $tid = I('request.tid', 0, 'intval');  // 大轉盤id,
    $wid = I('request.wid', 0, 'intval');  // 應用id,可去掉
    $token = $this->getOpenId();　　　　　　 // 獲取微信用戶的token

    // 定義數據庫
    $big_wheel = D('Big_wheel');   // 大轉盤設置表
    $big_wheel_log = M('big_wheel_log');  // 抽獎記錄表
    $big_code = M('big_wheel_code');    // 已抽中獎品記錄表

    // 查詢抽獎活動數據
    $where = " `id` = " . $tid;
    $list = $big_wheel->relation(true)->where($where)->find();

    // 查詢積分，若積分不足則無法參與抽獎
    $score = $this->duser['score'];
    if ($score < $list['score_num']) {
        echo json_encode(array('error' => 'score'));
        exit;
    }

    //已抽獎總次數
    $where_log = "`big_wheel_id`=" . $tid . " and `w_id`=" . $list['w_id'] . "  and `code`='" . $token . "'";
    $count = $big_wheel_log->where($where_log)->count();

    //減去額外獲得的抽獎機會 - 分享（此操作暫時隱藏）
    $map_share['wid'] = array('eq', $wid);
    $map_share['token'] = array('eq', $token);
    $map_share['big_wheel_id'] = array('eq', $tid);
    $count_share = M('big_wheel_share')->where($map_share)->count();
    $count = $count - $count_share;


    //當日限制次數
    if ($list['most_num_times'] > 0) {
        $where_log .= " and (addtime BETWEEN " . strtotime(date('Y-m-d 00:00:00')) . " and " . strtotime(date('Y-m-d 23:59:59')) . ")";
        $count_today = $big_wheel_log->where($where_log)->count();
        $count_today = $count_today - $count_share;//  當日抽獎次數減去額外獲得的抽獎次數

    }

    //判斷抽獎次數
    if ($count_today >= $list['most_num_times'] && $list['most_num_times'] > 0) {
        echo json_encode(array('error' => 'invalid_today', 'nums' => $list['most_num_times']));
        exit;
    }

    // 扣除積分
    M('app_dishop_duser')->where(array('id' => $this->duser['id']))->setDec('score', $list['score_num']);

    //插入抽獎記錄表
    $data['big_wheel_id'] = $tid;
    $data['w_id'] = $list['w_id'];
    $data['code'] = $token;
    $data['date'] = date('Y-m-d', time());
    $data['addtime'] = time();
    $big_wheel_log->add($data);

    /*
     * 獎項數組
     * 是一個二維數組，記錄了所有本次抽獎的獎項信息，
     * 其中id表示中獎等級，prize表示獎品，v表示中獎概率。
     * 注意其中的v必須為整數，你可以將對應的 獎項的v設置成0，即意味着該獎項抽中的幾率是0，
     * 數組中v的總和（基數），基數越大越能體現概率的准確性。
     * 本例中v的總和為100，那么中獎概率就是1%，
     * 如果v的總和是10000，那中獎概率就是萬分之一了。
     *
     */
    $prize_arr = array(
        '0' => array('id' => 1, 'prize' => '1', 'v' => $list['c_probability_one']),
        '1' => array('id' => 2, 'prize' => '謝謝參與', 'v' => $list['no_probability']),
        '2' => array('id' => 3, 'prize' => '2', 'v' => $list['c_probability_two']),
        '3' => array('id' => 4, 'prize' => '3', 'v' => $list['c_probability_three']),
    );

    foreach ($prize_arr as $key => $val) {
        $arr[$val['id']] = $val['v'];
    }

    $rid = $this->get_rand($arr); //根據概率獲取獎項id

    $res['yes'] = $prize_arr[$rid - 1]['prize']; //中獎項
    unset($prize_arr[$rid - 1]); //將中獎項從數組中剔除，剩下未中獎項
    shuffle($prize_arr); //打亂數組順序
    for ($i = 0; $i < count($prize_arr); $i++) {
        $pr[] = $prize_arr[$i]['prize'];
    }

    // 若抽中獎品，則存入庫中，並返回提示
    if ($res['yes'] == '1' || $res['yes'] == '2' || $res['yes'] == '3') {
        //這個是保存到數據庫表示你這個人抽中獎品
        if ($res['yes'] == '1') {
            // 查詢這是第幾次抽中此獎品，若抽中次數大於獎品數，則此次抽中的獎品作廢
            $code_count = $big_code->where(array('prizetype' => 1, 'big_wheel_id' => $tid))->count();
            if ($code_count >= $list['c_num_one']) {
                $data = array('prizetype' => null, 'success' => true);
                echo json_encode($data);
                exit;
            }
            $code['category'] = $list['c_name_one'];
        } elseif ($res['yes'] == '2') {
            // 查詢這是第幾次抽中此獎品，若抽中次數大於獎品數，則此次抽中的獎品作廢
            $code_count = $big_code->where(array('prizetype' => 2, 'big_wheel_id' => $tid))->count();
            if ($code_count >= $list['c_num_two']) {
                $data = array('prizetype' => null, 'success' => true);
                echo json_encode($data);
                exit;
            }
            $code['category'] = $list['c_name_two'];
        } elseif ($res['yes'] == '3') {
            // 查詢這是第幾次抽中此獎品，若抽中次數大於獎品數，則此次抽中的獎品作廢
            $code_count = $big_code->where(array('prizetype' => 3, 'big_wheel_id' => $tid))->count();
            if ($code_count >= $list['c_num_three']) {
                $data = array('prizetype' => null, 'success' => true);
                echo json_encode($data);
                exit;
            }
            $code['category'] = $list['c_name_three'];
        }
        $code['sn_id'] = 'sn' . time() . mt_rand(10000, 99999);
        $code['w_id'] = $list['w_id'];
        $code['big_wheel_id'] = $tid;
        $code['prizetype'] = $res['yes'];
        $code['code'] = $token;
        $code['winners_time'] = time();
        $code['state'] = 1;
        $big_code->add($code);
        $data = array('sn' => $code['sn_id'], 'prizetype' => $res['yes'], 'success' => true);
        echo json_encode($data);
        exit;
    } else {
        $data = array('prizetype' => null, 'success' => true);
        echo json_encode($data);
        exit;
    }
}

// 抽獎概率計算
public function get_rand($proArr)
{
    $result = '';

    //概率數組的總概率精度
    $proSum = array_sum($proArr);

    //概率數組循環
    foreach ($proArr as $key => $proCur) {
        $randNum = mt_rand(1, $proSum);
        if ($randNum <= $proCur) {
            $result = $key;
            break;
        } else {
            $proSum -= $proCur;
        }
    }
    unset ($proArr);
    return $result;
}