php 固定红包 + 随机红包算法

<?php
/**
 * 随机红包+固定红包算法[策略模式]
 * copyright (c) 2016 http://blog.csdn.net/CleverCode
 */

//配置传输数据DTO
class RangeDto
{

    //红包总金额
    public $totalMoney;

    //红包数量
    public $num;

    //范围开始
    public $rangeStart;

    //范围结算
    public $rangeEnd;

    //生成红包策略
    public $builderStrategy;

    //随机红包剩余规则
    public $randFormatType; //Can_Left：不修数据,可以有剩余；No_Left：不能有剩余

    public static function create($totalMoney, $num, $rangeStart, $rangEnd,$builderStrategy, $randFormatType = 'No_Left')
    {
        $self = new self();
        $self->num = $num;
        $self->rangeStart = $rangeStart;
        $self->rangeEnd = $rangEnd;
        $self->totalMoney = $totalMoney;
        $self->builderStrategy = $builderStrategy;
        $self->randFormatType = $randFormatType;
        return $self;
    }

}

//红包生成器接口
interface IBuilderStrategy
{
    //创建红包
    public function create();

    //设置配置
    public function setOption(RangeDto $option);

    //是否可以生成红包
    public function isCanBuilder();

    //生成红包函数
    public function fx($x);
}

//固定等额红包策略
class EqualPackageStrategy implements IBuilderStrategy
{
    //单个红包金额
    public $oneMoney;

    //数量
    public $num;

    public function __construct($option = null)
    {
        if ($option instanceof RangeDto) {
            $this->setOption($option);
        }
    }

    public function setOption(RangeDto $option)
    {
        $this->oneMoney = $option->rangeStart;
        $this->num = $option->num;
    }

    public function create()
    {

        $data = array();
        if (false == $this->isCanBuilder()) {
            return $data;
        }

        $data = array();
        if (false == is_int($this->num) || $this->num <= 0) {
            return $data;
        }
        for ($i = 1; $i <= $this->num; $i++) {
            $data[$i] = $this->fx($i);
        }
        return $data;
    }

    /**
     * 等额红包的方程是一条直线
     *
     * @param mixed $x
     * @access public
     * @return void
     */
    public function fx($x)
    {
        return $this->oneMoney;
    }

    /**
     * 是否能固定红包
     *
     * @access public
     * @return void
     */
    public function isCanBuilder()
    {
        if (false == is_int($this->num) || $this->num <= 0) {
            return false;
        }

        if (false == is_numeric($this->oneMoney) || $this->oneMoney <= 0) {
            return false;
        }

        //单个红包小于1分
        if ($this->oneMoney < 0.01) {
            return false;
        }

        return true;

    }

}

//随机红包策略(三角形)
class RandTrianglePackageStrategy implements IBuilderStrategy
{
    //总额
    public $totalMoney;

    //红包数量
    public $num;

    //随机红包最小值
    public $minMoney;

    //随机红包最大值
    public $maxMoney;

    //修数据方式：NO_LEFT: 红包总额 = 预算总额；CAN_LEFT: 红包总额 <= 预算总额
    public $formatType;

    //预算剩余金额
    public $leftMoney;

    public function __construct($option = null)
    {
        if ($option instanceof RangeDto) {
            $this->setOption($option);
        }
    }

    public function setOption(RangeDto $option)
    {
        $this->totalMoney = $option->totalMoney;
        $this->num = $option->num;
        $this->formatType = $option->randFormatType;
        $this->minMoney = $option->rangeStart;
        $this->maxMoney = $option->rangeEnd;
        $this->leftMoney = $this->totalMoney;
    }

    /**
     * 创建随机红包
     *
     * @access public
     * @return void
     */
    public function create()
    {

        $data = array();
        if (false == $this->isCanBuilder()) {
            return $data;
        }

        $leftMoney = $this->leftMoney;
        for ($i = 1; $i <= $this->num; $i++) {
            $data[$i] = $this->fx($i);
            $leftMoney = $leftMoney - $data[$i];
        }

        //修数据
        list($okLeftMoney, $okData) = $this->format($leftMoney, $data);

        //随机排序
        shuffle($okData);
        $this->leftMoney = $okLeftMoney;

        return $okData;
    }

    /**
     * 是否能够发随机红包
     *
     * @access public
     * @return void
     */
    public function isCanBuilder()
    {
        if (false == is_int($this->num) || $this->num <= 0) {
            return false;
        }

        if (false == is_numeric($this->totalMoney) || $this->totalMoney <= 0) {
            return false;
        }

        //均值
        $avgMoney = $this->totalMoney / 1.0 / $this->num;

        //均值小于最小值
        if ($avgMoney < $this->minMoney) {
            return false;
        }

        return true;

    }

    /**
     * 获取剩余金额
     *
     * @access public
     * @return void
     */
    public function getLeftMoney()
    {
        return $this->leftMoney;
    }

    /**
     * 随机红包生成函数。三角函数。[(1,0.01),($num/2,$avgMoney),($num,0.01)]
     *
     * @param mixed $x ,1 <= $x <= $this->num;
     * @access public
     * @return void
     */
    public function fx($x)
    {

        if (false == $this->isCanBuilder()) {
            return 0;
        }

        if ($x < 1 || $x > $this->num) {
            return 0;
        }

        $x1 = 1;
        $y1 = $this->minMoney;

        //我的峰值
        $y2 = $this->maxMoney;

        //中间点
        $x2 = ceil($this->num / 1.0 / 2);

        //最后点
        $x3 = $this->num;
        $y3 = $this->minMoney;

        //当x1,x2,x3都是1的时候(竖线)
        if ($x1 == $x2 && $x2 == $x3) {
            return $y2;
        }

        // '/_\'三角形状的线性方程
        //'/'部分
        if ($x1 != $x2 && $x >= $x1 && $x <= $x2) {

            $y = 1.0 * ($x - $x1) / ($x2 - $x1) * ($y2 - $y1) + $y1;
            return number_format($y, 2, '.', '');
        }

        //'\'形状
        if ($x2 != $x3 && $x >= $x2 && $x <= $x3) {

            $y = 1.0 * ($x - $x2) / ($x3 - $x2) * ($y3 - $y2) + $y2;
            return number_format($y, 2, '.', '');
        }

        return 0;

    }

    /**
     * 格式化修红包数据
     *
     * @param mixed $leftMoney
     * @param array $data
     * @access public
     * @return void
     */
    private function format($leftMoney, array $data)
    {

        //不能发随机红包
        if (false == $this->isCanBuilder()) {
            return array($leftMoney, $data);
        }

        //红包剩余是0
        if (0 == $leftMoney) {
            return array($leftMoney, $data);
        }

        //数组为空
        if (count($data) < 1) {
            return array($leftMoney, $data);
        }

        //如果是可以有剩余，并且$leftMoney > 0
        if ('Can_Left' == $this->formatType
            && $leftMoney > 0) {
            return array($leftMoney, $data);
        }

        //我的峰值
        $myMax = $this->maxMoney;

        // 如果还有余钱，则尝试加到小红包里，如果加不进去，则尝试下一个。
        while ($leftMoney > 0) {
            $found = 0;
            foreach ($data as $key => $val) {
                //减少循环优化
                if ($leftMoney <= 0) {
                    break;
                }

                //预判
                $afterLeftMoney = (double)$leftMoney - 0.01;
                $afterVal = (double)$val + 0.01;
                if ($afterLeftMoney >= 0 && $afterVal <= $myMax) {
                    $found = 1;
                    $data[$key] = number_format($afterVal, 2, '.', '');
                    $leftMoney = $afterLeftMoney;
                    //精度
                    $leftMoney = number_format($leftMoney, 2, '.', '');
                }
            }

            //如果没有可以加的红包，需要结束,否则死循环
            if ($found == 0) {
                break;
            }
        }
        //如果$leftMoney < 0 ,说明生成的红包超过预算了，需要减少部分红包金额
        while ($leftMoney < 0) {
            $found = 0;
            foreach ($data as $key => $val) {
                if ($leftMoney >= 0) {
                    break;
                }
                //预判

                $afterLeftMoney = (double)$leftMoney + 0.01;
                $afterVal = (double)$val - 0.01;
                if ($afterLeftMoney <= 0 && $afterVal >= $this->minMoney) {
                    $found = 1;
                    $data[$key] = number_format($afterVal, 2, '.', '');
                    $leftMoney = $afterLeftMoney;
                    $leftMoney = number_format($leftMoney, 2, '.', '');
                }
            }

            //如果一个减少的红包都没有的话，需要结束，否则死循环
            if ($found == 0) {
                break;
            }
        }
        return array($leftMoney, $data);
    }

}

//维护策略的环境类
class RedPackageBuilder
{

    // 实例
    protected static $_instance = null;

    /**
     * Singleton instance（获取自己的实例）
     *
     * @return MemcacheOperate
     */
    public static function getInstance()
    {
        if (null === self::$_instance) {
            self::$_instance = new self();
        }
        return self::$_instance;
    }

    /**
     * 获取策略【使用反射】
     *
     * @param string $type 类型
     * @return void
     */
    public function getBuilderStrategy($type)
    {
        $class = $type . 'PackageStrategy';

        if (class_exists($class)) {
            return new $class();
        } else {
            throw new Exception("{$class} 类不存在！");
        }
    }

    public function getRedPackageByDTO(RangeDto $optionDTO)
    {
        //获取策略
        $builderStrategy = $this->getBuilderStrategy($optionDTO->builderStrategy);

        //设置参数
        $builderStrategy->setOption($optionDTO);

        return $builderStrategy->create();
    }

}

class Client
{
    public static function main()
    {
        //固定红包
        $dto = RangeDto::create(1000, 10, 100, 100, 'Equal');
        $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto);
        echo '<pre>';
        print_r($data);

        //随机红包[修数据]
        $dto = RangeDto::create(5, 10, 0.01, 0.99, 'RandTriangle');
        $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto);
        echo '<pre>';
        print_r($data);

        //随机红包[不修数据]
        $dto = RangeDto::create(5, 10, 0.01, 0.99, 'RandTriangle', 'Can_Left');
        $data = RedPackageBuilder::getInstance()->getRedPackageByDTO($dto);
        echo '<pre>';
        print_r($data);

    }
}

Client::main();