一个简单的抽奖测试原型

<?php
/**
 * 抽奖程序
 *
 * @File: lucky.php
 * @Author: zzxworld
 * @Email: zzxworld@gmail.com
 * @Date: 2012-05-09
 */

$timer = microtime(true);

/** 手动配置的参数 **/
# 奖池大小
$lucky_size = 1000;
# 最高金额用户的中奖机率,不能超过奖池大小
$star_user_rate = 100;
# 一等奖奖金
$lucky_first = 100;
# 二等奖奖金
$lucky_second = 50;
# 三等奖奖金
$lucky_third = 25;
# 普通奖最大金额
$lucky_normal_max = 10;
# 普通奖最小金额
$lucky_normal_min = 1;

/** 自动从系统取值的参数 **/
# 奖金总金额
$lucky_amount = 578;
# 拥有最多资产的用户的账户金额
$star_user_amount = 134;

# 当前用户金额
$user_amount = isset($argv[1]) ? intval($argv[1]) : 0;
if ($user_amount < 1) {
    die('请在命令后面设置一个用户金额.' . chr(10));
}

# 计算当前用户中奖机率
$user_rate = $star_user_rate/$lucky_size/$star_user_amount*$user_amount;

# 根据中奖机率计算奖金个数
$lucky_num = intval($user_rate * $lucky_size);

# 初始化奖池
$lucky_pool = array_fill(0, $lucky_size, 0);

# 中奖机率小于1的调整为1
if ($lucky_num < 1) {
    $lucky_num = 1;
} 

# 安排奖池中的奖项
$lucky_items = array('first', 'second', 'third', 'normal');
$lucky_num += 3;

# 按奖金总额去除一，二，三等奖项
if ($lucky_amount < $lucky_first) {
    $lucky_num -= 1;
    unset($lucky_items['first']);
}

if ($lucky_amount < $lucky_second) {
    $lucky_num -= 1;
    unset($lucky_items['second']);
}

if ($lucky_amount < $lucky_third) {
    $lucky_num -= 1;
    unset($lucky_items['third']);
}

# 在奖池中随机生成奖项
foreach(array_rand($lucky_pool, $lucky_num) as $key) {
    $name = $lucky_items[array_rand($lucky_items)];
    if (!isset($create_lucky_first) && $name == 'first') {
        $lucky_pool[$key] = $lucky_first;
        $create_lucky_first = true;
        continue;
    }

    if (!isset($create_lucky_second) && $name == 'second') {
        $lucky_pool[$key] = $lucky_second;
        $create_lucky_second = true;
        continue;
    }

    if (!isset($create_lucky_third) && $name == 'third') {
        $lucky_pool[$key] = $lucky_third;
        $create_lucky_third = true;
        continue;
    }

    if ($name == 'normal') {
        $lucky_pool[$key] = rand($lucky_normal_min, $lucky_normal_max);
    }

}

# 抽奖
$result = $lucky_pool[rand(0, $lucky_size)];

echo '奖池大小:' . $lucky_size . chr(10);
echo '奖金总金额:' . $lucky_amount . chr(10);
echo '一等奖奖金:' . $lucky_first . chr(10);
echo '二等奖奖金:' . $lucky_second . chr(10);
echo '三等奖奖金:' . $lucky_third . chr(10);
echo '普通奖奖金:' . $lucky_normal_min . ' - ' . $lucky_normal_max . chr(10);
echo '明星用户资金总额:' . $star_user_amount . chr(10);
echo '明星用户中奖机率:' . ($star_user_rate/$lucky_size) . chr(10) . chr(10);

echo '当前用户资金总额:' . $user_amount . chr(10);
echo '当前用户中奖机率:' . $user_rate . chr(10);
echo '当前用户奖池中的奖项:'; 
    foreach($lucky_items as $name) {
        switch($name) {
            case 'first':
                echo '一等奖(1),';
                $lucky_num--;
                break;
            case 'second':
                echo '二等奖(1),';
                $lucky_num--;
                break;
            case 'third':
                echo '三等奖(1),';
                $lucky_num--;
                break;
            case 'normal':
                echo '普通奖(' . $lucky_num . ')';
                break;
        }
    }
    echo chr(10);
echo '当前用户抽奖结果：';
    if ($result == $lucky_first) {
        echo '一等奖 ' . $result . '元';
    } elseif($result == $lucky_second) {
        echo '二等奖 ' . $result . '元';
    } elseif($result == $lucky_third) {
        echo '三等奖 ' . $result . '元';
    } elseif($result >= $lucky_normal_min && $result <= $lucky_normal_max) {
        echo '普通奖 ' . $result . '元';
    } else {
        echo '没有中奖';
    }
    echo chr(10); 
    echo chr(10);

echo '执行耗时:' . (microtime(true) - $timer) . '秒' . chr(10);