一、初始化奖品
id 奖品的id
pid 奖品的自定义id
type 奖品类型，1、虚拟奖品 2、实物奖品 3、礼包码 待扩充
name 奖品名称
total 奖品总数
chance 获奖概率/抽奖基数10000
daynum 每日数量限制
pay 充值限制
$prize = [
['id' => 1, 'pid' => 11, 'type' => 1, 'name' => '典藏英雄', 'total' => 20, 'chance' => 1000, 'daynum' => 10, 'pay' => 2000 ],
['id' => 2, 'pid' => 12, 'type' => 1, 'name' => '史诗皮肤', 'total' => 40, 'chance' => 1000, 'daynum' => 10, 'pay' => 4000 ],
['id' => 3, 'pid' => 13, 'type' => 1, 'name' => '钻石奖励', 'total' => 80, 'chance' => 1000, 'daynum' => 10, 'pay' => 4000 ],
['id' => 4, 'pid' => 14, 'type' => 1, 'name' => '荣耀水晶', 'total' => 20, 'chance' => 1000, 'daynum' => 10, 'pay' => 8000 ]
];
二、谢谢参与
$thanks_prize = [
'id' => 0,
'pid' => 0,
'type' => 1,
'name' => '谢谢参与'
];
三、过滤抽奖、如充值条件
$pay_total = 7000;
foreach ($prize as $key => $value) {
if($value['pay'] > $pay_total) unset($prize[$key]);
}
四、重组概率
$now_chance = array_sum(array_column($prize, 'chance'));
$remain_chance = 10000 - $now_chance;
$prize[] = ['id' => 0, 'pid' => 0, 'type' => 1, 'name' => '谢谢参与', 'total' => 0, 'chance' => $remain_chance, 'daynum' => 0, 'pay' => 0];
$award = [];
$num = 0;
foreach ($prize as $_v) {
$num += $_v['chance'];
$award[] = ['id' => $_v['id'], 'pid' => $_v['pid'], 'type' => $_v['type'], 'name' => $_v['name'], 'total' => $_v['total'], 'chance' => $num, 'daynum' => $_v['daynum'], 'pay' => $_v['pay']];
}
初步过滤后，重构新的抽奖信息，加入谢谢参与
第二步重组概率
五、进行抽奖
$rand = mt_rand(1, 10000);
$result = [];
foreach ($award as $_k => $_v) {
if ($_k == 0) {
if ($rand > 0 && $rand <= $_v['chance']) {
$result = $_v;
break;
}
} else {
if ($rand > $award[$_k - 1]['chance'] && $rand <= $_v['chance']) {
$result = $_v;
break;
}
}
}
开始抽奖，并返回抽中的结果
六、过滤回调
//此处应该查询数据库，查看该奖品已经抽中的数量
$yet_num = 50;
if($result['pid'] != 0 && $yet_num > $result['total']) {
$result = $thanks_prize;
}
//此处应该查询数据库，查看该奖品今日已经抽中的数量
$yet_today_num = 50;
if($result['pid'] != 0 && $yet_today_num > $result['daynum']) {
$result = $thanks_prize;
}
二次过滤，奖品总数的限制以及奖品的每日限制等
七、最终抽奖结果
//删除敏感字段
unset($result['total'],$result['chance'],$result['daynum'],$result['pay']);
//返回最终抽奖结果
echo json_encode([
'prize' => $award,
'rand' => $rand,
'result' => $result
]);
八、抽奖封装成类
<?php
/**
* Created by PhpStorm.
* User: autofelix
* Date: 2020/10/30
* Time: 13:14
* Desc: 抽奖算法
*/
class Lottery
{
/**
* 概率基数
* @var int
*/
private $total_chance = 10000;
/**
* 谢谢参与奖励
* @var array
*/
private $thanks_prize = [
'id' => 0,
'pid' => 0,
'type' => 1,
'name' => '谢谢参与'
];
/**
* 奖池
* @var array
*/
private $prize = [
['id' => 1, 'pid' => 11, 'type' => 1, 'name' => '典藏英雄', 'total' => 20, 'chance' => 1000, 'daynum' => 10, 'pay' => 2000 ],
['id' => 2, 'pid' => 12, 'type' => 1, 'name' => '史诗皮肤', 'total' => 40, 'chance' => 1000, 'daynum' => 10, 'pay' => 4000 ],
['id' => 3, 'pid' => 13, 'type' => 1, 'name' => '钻石奖励', 'total' => 80, 'chance' => 1000, 'daynum' => 10, 'pay' => 4000 ],
['id' => 4, 'pid' => 14, 'type' => 1, 'name' => '荣耀水晶', 'total' => 20, 'chance' => 1000, 'daynum' => 10, 'pay' => 8000 ]
];
/**
* Lottery constructor.
*/
public function __construct()
{
}
/**
* @return int
*/
private function get_user_pay()
{
//这里应该调用接口，返回用户正确的充值信息
return 3000;
}
/**
* 重构奖池、重组概率
* @return array
*/
private function init_lottery_pond()
{
$award = [];
//充值限制
$user_pay = $this->get_user_pay();
foreach ($this->prize as $key => $value) {
if($value['pay'] <= $user_pay) unset($this->prize[$key]);
}
//加入谢谢惠顾
$now_chance = array_sum(array_column($this->prize, 'chance'));
$remain_chance = $this->total_chance - $now_chance;
$this->prize[] = ['id' => 0, 'pid' => 0, 'type' => 1, 'name' => '谢谢参与', 'total' => 0, 'chance' => $remain_chance, 'daynum' => 0, 'pay' => 0];
//重组概率
$num = 0;
foreach ($this->prize as $_v) {
$num += $_v['chance'];
$award[] = ['id' => $_v['id'], 'pid' => $_v['pid'], 'type' => $_v['type'], 'name' => $_v['name'], 'total' => $_v['total'], 'chance' => $num, 'daynum' => $_v['daynum'], 'pay' => $_v['pay']];
}
return $award;
}
/**
* 获取抽奖结果
* @return array
*/
public function get_prize()
{
$award = $this->init_lottery_pond();
$rand = mt_rand(1, $this->total_chance);
$result = [];
foreach ($award as $_k => $_v) {
if ($_k == 0) {
if ($rand > 0 && $rand <= $_v['chance']) {
$result = $_v;
break;
}
} else {
if ($rand > $award[$_k - 1]['chance'] && $rand <= $_v['chance']) {
$result = $_v;
break;
}
}
}
$result = $this->filter($result);
return $result;
}
/**
* 抽奖过滤回调函数
* @param $result
* @return array
*/
public function filter($result)
{
//奖品总数限制，此处应该查数据库
$yet_num = 50;
if($result['pid'] != 0 && $yet_num > $result['total']) {
$result = $this->thanks_prize;
}
//奖品每日数量限制，此处应该查数据库
$yet_today_num = 50;
if($result['pid'] != 0 && $yet_today_num > $result['daynum']) {
$result = $this->thanks_prize;
}
//不暴露敏感信息
unset($result['total'], $result['chance'], $result['daynum'], $result['pay'] );
return $result;
}
private function __clone()
{
}
}
echo json_encode((new Lottery())->get_prize());
