123 lines
3.4 KiB
PHP
123 lines
3.4 KiB
PHP
<?php
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namespace app\common\library;
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class RedpacketLua
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{
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/**
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* 抢红包Lua脚本
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* 保证原子性操作，防止超抢
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*/
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public static function grabRedpacketScript()
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{
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return <<<LUA
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-- KEYS[1]: 红包key, KEYS[2]: 用户集合key, KEYS[3]: 用户ID
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-- ARGV[1]: 当前时间
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local redpacketKey = KEYS[1]
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local userSetKey = KEYS[2]
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local userId = KEYS[3]
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local currentTime = tonumber(ARGV[1])
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-- 检查红包是否存在
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local redpacketData = redis.call('HGETALL', redpacketKey)
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if not redpacketData or #redpacketData == 0 then
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return {0, "红包不存在", 0}
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end
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-- 将哈希数据转为table
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local redpacket = {}
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for i = 1, #redpacketData, 2 do
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redpacket[redpacketData[i]] = redpacketData[i + 1]
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end
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-- 检查红包状态
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local status = tonumber(redpacket['status'])
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local startTime = tonumber(redpacket['start_time'])
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local endTime = tonumber(redpacket['end_time'])
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if status == 0 then
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if currentTime < startTime then
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return {0, "红包还未开始", 0}
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else
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-- 更新状态为进行中(1)
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redis.call('HSET', redpacketKey, 'status', 1)
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status = 1
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end
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end
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if status ~= 1 then
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return {0, "红包已结束", 0}
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end
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if currentTime > endTime then
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redis.call('HSET', redpacketKey, 'status', 2)
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return {0, "红包已结束", 0}
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end
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-- 检查是否已经抢过
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local hasGrabbed = redis.call('SISMEMBER', userSetKey, userId)
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if hasGrabbed == 1 then
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return {0, "已经抢过该红包", 0}
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end
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-- 检查是否还有剩余
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local leftAmount = tonumber(redpacket['left_amount'])
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local leftCount = tonumber(redpacket['left_count'])
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if leftCount <= 0 or leftAmount <= 0 then
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return {0, "红包已抢完", 0}
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end
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-- 计算红包金额（核心修复：解决3金币2红包场景第二个红包为0的问题）
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local amount = 0
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local isFinished = 0
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if leftCount == 1 then
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-- 最后一个红包，获得剩余所有金额（确保至少1）
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amount = leftAmount
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isFinished = 1
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else
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-- 随机算法：二倍均值法（适配整数+保底逻辑，彻底避免0）
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-- 1. 基础二倍均值（整数处理）
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local avg = leftAmount / leftCount
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local maxAmount = math.floor(avg * 2)
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-- 2. 核心修复：保底限制 - 最大金额不能超过「剩余金额 - (剩余个数 - 1)」
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-- 确保剩下的每个红包至少能分到1个金币（比如3金币2红包：3 - (2-1) = 2，第一个红包最多抢2）
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local safeMax = leftAmount - (leftCount - 1)
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maxAmount = math.min(maxAmount, safeMax)
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-- 3. 强制保证最小金额为1，最大金额不小于1
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maxAmount = math.max(maxAmount, 1)
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-- 4. 随机生成1到maxAmount之间的整数（绝对不会出现0）
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amount = math.random(1, maxAmount)
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-- 5. 整数场景下的抢完判断（无需浮点数误差处理）
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if (leftCount - 1) == 1 and (leftAmount - amount) == 0 then
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isFinished = 1
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end
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end
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-- 更新红包数据（整数处理，无小数）
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local newLeftAmount = leftAmount - amount
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local newLeftCount = leftCount - 1
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redis.call('HSET', redpacketKey, 'left_amount', newLeftAmount)
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redis.call('HSET', redpacketKey, 'left_count', newLeftCount)
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-- 标记用户已抢
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redis.call('SADD', userSetKey, userId)
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-- 如果抢完了，更新状态为已结束(2)
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if isFinished == 1 then
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redis.call('HSET', redpacketKey, 'status', 2)
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end
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return {1, tostring(amount), isFinished}
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LUA;
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}
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} |