php 实现红包

PHP 实现红包功能

固定金额红包

固定金额红包是指每个红包的金额相同，适用于需要均分红包的场景。

function fixedAmountRedPacket($totalAmount, $num) {
    if ($num <= 0) {
        return [];
    }
    $eachAmount = $totalAmount / $num;
    return array_fill(0, $num, $eachAmount);
}

随机金额红包

随机金额红包是指每个红包的金额随机生成，但总和等于总金额。

function randomAmountRedPacket($totalAmount, $num) {
    if ($num <= 0) {
        return [];
    }
    $result = [];
    $remainingAmount = $totalAmount;
    $remainingNum = $num;
    for ($i = 1; $i < $num; $i++) {
        $max = $remainingAmount / $remainingNum * 2;
        $amount = mt_rand(1, $max * 100) / 100;
        $result[] = $amount;
        $remainingAmount -= $amount;
        $remainingNum--;
    }
    $result[] = $remainingAmount;
    shuffle($result);
    return $result;
}

带最大最小限制的随机红包

在某些场景下，需要限制每个红包的最小和最大金额。

function limitedRandomRedPacket($totalAmount, $num, $minAmount, $maxAmount) {
    if ($num <= 0 || $minAmount * $num > $totalAmount || $maxAmount * $num < $totalAmount) {
        return [];
    }
    $result = [];
    $remainingAmount = $totalAmount;
    for ($i = 1; $i < $num; $i++) {
        $safeMin = max($minAmount, $remainingAmount - ($num - $i) * $maxAmount);
        $safeMax = min($maxAmount, $remainingAmount - ($num - $i) * $minAmount);
        $amount = mt_rand($safeMin * 100, $safeMax * 100) / 100;
        $result[] = $amount;
        $remainingAmount -= $amount;
    }
    $result[] = $remainingAmount;
    shuffle($result);
    return $result;
}

使用示例

$totalAmount = 100; // 总金额
$num = 10; // 红包数量

// 固定金额红包
$fixedRedPacket = fixedAmountRedPacket($totalAmount, $num);
print_r($fixedRedPacket);

// 随机金额红包
$randomRedPacket = randomAmountRedPacket($totalAmount, $num);
print_r($randomRedPacket);

// 带限制的随机红包
$minAmount = 5;
$maxAmount = 15;
$limitedRedPacket = limitedRandomRedPacket($totalAmount, $num, $minAmount, $maxAmount);
print_r($limitedRedPacket);

注意事项

• 金额计算时建议使用整数运算（如分单位），避免浮点数精度问题。
• 随机红包算法需要确保剩余金额足够分配后续红包。
• 实际应用中可能需要考虑并发抢红包的场景，建议结合数据库事务处理。