在php中计算每月包（产品）价格

Question

我已经创建了电子商务网站，它即将提供午餐和晚餐服务。我在这里提出问题/问题是因为我知道这里有很多可以帮助我的传说。我已经在网站上添加了包/计划部分。

 1. Weekly
 2. Monthly

这是订购产品的页面问题形式的截图：
我可以轻松计算每周价格，例如，如果产品价格 100 并且用户选择了每周计划，并且他选择了从周一到周六的天数（仅限一周中的 6 天），那么我们可以使用 6*100 = 600 轻松计算价格。
但是如何计算每月价格呢？
例如：如果用户选择了每月计划并选择每周 6 天，从周一到周六，或者任何他想选择的日子名称。然后他下订单。现在，

6 * 4 = 24 (6 days * 4 weeks)
24 * 100 = 2400 (days * product price)

但它只计算 4 周，而不是整月。我想计算整月。如果我检查当前月份是 30 天，那么 4 (weeks) + 2 days，如果当前月份是 31 天，那么 4 (weeks) + 3 days。看起来很简单，但它也很危险，因为如果 + 2 或 +3 天是用户在订购月包期间未选中的那些日子怎么办。
这是我的代码：

<?php
    $pCartProducts = $pcart->getPlanCartProducts($userid);
?>

<tbody>
    <?php
        if($pCartProducts){
            $finalPrice = 0;
            while($pcPro = $pCartProducts->fetch_assoc()){
                $planName = $pcPro['plan_name'];
    ?>

    <tr>
        <td data-title="Plan">
            <?php echo $planName; ?>
        </td>
        <?php 

            $pro_price = $pcPro['pro_price'];
            $plan_days = $pcPro['plan_days']; // if user selected 6 days in a week
            $totaldays = $plan_days * 4; // 6 * 4 weeks = 24

            // Calculating current month days
            $month = date('m');
            $year = date('Y');
            $cal_days = cal_days_in_month(CAL_GREGORIAN, $month, $year);

            if($planName == 'Weekly'){

                $total_price = $pro_price * $plan_days;

            } elseif($planName == 'Monthly'){

                if($cal_days == '30'){
                     $final_tdays = $totaldays + 2; // + 2 days
                } elseif($cal_days == '31'){
                    $final_tdays = $totaldays + 3;  // + 3 days
                } elseif($cal_days == '29'){
                    $final_tdays = $totaldays + 1;  // + 1 day
                } elseif($cal_days == '28'){
                    $final_tdays = $totaldays;      // normal
                }

                $total_price = $final_tdays * $pro_price; // final days * product price

            }

        ?>
        <td data-title="Price">
            <span>Rs./<?php echo $total_price; ?></span>
        </td>
    </tr>
    <?php } } ?>
</tbody>

其他截图：

有人可以帮我计算一周中选定日期的每月价格吗？ 请帮帮我

Answer 1

你有两个选择

选项 1

考虑到月份是固定的天数，比如 30 或 28 天，然后继续你的工作，就这么简单。

选项 2

一个月就是一个月，可以是28天、29、30或31。

好的，在这种方法中，我将计算客户使用您的服务的天数，然后乘以价格。我利用内置的DateTime 类和它的朋友DateInterval 和strtotime 的强大功能，根据他将使用该服务的星期几使这种方法适用于每周选项和每月选项。它将循环抛出从开始日期开始的天数，如果在计划中选择了这一天，例如（星期日），它将计算它。

检查一下，并根据需要进行更改，我尝试对其发表评论，但如果有不明显的地方，请发表评论。

<?php
$tz = new DateTimeZone("UTC");
//lets say he chosed the service on Monday and Tuesday and Wednesday
$days = "Monday ,Tuesday, Wednesday";// <-- change to user input
$planDays = translateWeekDaysToNumbers($days);
$planName = "Weekly";// <- change as user input

if($planName == 'Weekly'){
    $weekOrMonth = "week";
} else if ($planName == 'Monthly'){
    $weekOrMonth = "month";
} else {
    //TODO: throw error
}

$startString = "2019-02-01 00:00:00"; // <- change later to "now"
$startDate = new DateTime($startString, $tz);
$afterMonth = new DateTime("@" . strtotime("+1 $weekOrMonth", $startDate->format("U")));

$numberOfDays = $afterMonth->diff($startDate)->days;


$daysOfService = 0; // what we need to calculate

for($i = 0; $i<$numberOfDays + 1; $i++){
    $dateInterval = new DateInterval("P{$i}D");
    $startDate->add($dateInterval);
    if (in_array($startDate->format("w"), $planDays)) $daysOfService ++;
    $startDate->sub($dateInterval);//reset to first day
}

$pro_price = 100;// <--- change to your price from the DB
$totalPrice = $daysOfService * $pro_price;
echo $daysOfService . "\n";
echo $totalPrice . "\n";
exit;

/**
 * expects string like "Monday ,Tuesday, Wednesday"
   separated by comma. case is insensitive
 */
function translateWeekDaysToNumbers(string $days)
{
    
    //dont change the numbers as they are the given by ->format("w")
    $daysNumbers = [
        "sunday" => 0,
        "monday" => 1,
        "tuesday" => 2,
        "wednesday" => 3,
        "thursday" => 4,
        "friday" => 5,
        "saturday" => 6
    ];

    $days = explode(",", $days);
    $planDays = [];
    foreach($days as $day){
        $day = strtolower(trim($day));
        // if unexpected day name is provided
        // an undefined index warning will be shown
        // better than continue silently 
        $planDays[] = $daysNumbers[$day];
    }
    return $planDays;
}

现场演示https://3v4l.org/IVFF7

Answer 2

您可以通过此代码更新您的每月状况

         elseif($planName == 'Monthly'){
        // suppose data are saved for on day(means client want order on these day) like Monday, Tuesday, Wednesday, Thursday 
        // it means 'Friday','Saturday','Sunday' is offday for him

        $weekDay = ['Monday', 'Tuesday', 'Wednesday', 'Thursday','Friday','Saturday','Sunday'];

        $onDay = 'Monday,Tuesday,Wednesday,Thursday';

        $onDayArr = explode(',', $onDay);
        $OffDayArr = [];
        foreach ($weekDay as $value) {
            if(!in_array($value, $onDayArr)) {
                $OffDayArr[] = $value;
            }
        }
        $count = 0;
        foreach ($OffDayArr as $$clientOffDay) {
            $str = 'first '.$clientOffDay.' '.$year.'-'.$month.'';
            $monthFisrtOffDay = date("j", strtotime($str));

            while($cal_days >= $monthFisrtOffDay) {
                $monthFisrtOffDay +=7;
                $count++;
            }
        }

        $total_price = $pro_price * ($cal_days-$count);
    }