140 lines
4.4 KiB
TypeScript
140 lines
4.4 KiB
TypeScript
"use server"
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import { db } from "@/app/server/db"
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import { redPackets } from "@/app/server/schema/red-packet"
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import { redPacketDraws } from "@/app/server/schema/red-packet-draws"
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import { eq, sql } from "drizzle-orm"
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import { randomUUID } from "crypto"
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import { formatAmount } from "@/lib/format-amount"
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import { formatAmountFromInt, parseAmountToInt, randomBigInt } from "@/lib/utils"
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type DrawResult =
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| { ok: true; amount: string }
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| { ok: false; message: string }
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export async function drawRedPacket(
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redPacketId: string,
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userId: string
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): Promise<DrawResult> {
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return await db.transaction(async (tx) => {
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/* 1️⃣ 锁定红包行 */
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const [packet] = await tx
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.select()
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.from(redPackets)
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.where(eq(redPackets.id, redPacketId))
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.for("update")
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if (!packet) {
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return { ok: false, message: "红包不存在" }
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}
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/* 2 已抽数量 & 剩余数量 */
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const [{ usedCount }] = await tx
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.select({
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usedCount: sql<number>`COUNT(*)::int`,
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})
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.from(redPacketDraws)
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.where(eq(redPacketDraws.redPacketId, redPacketId))
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const remainingCount = packet.count - usedCount
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if (remainingCount <= 0) {
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return { ok: false, message: "红包已被抽完" }
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}
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/* 3 用户抽取次数校验 */
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const [{ count }] = await tx
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.select({
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count: sql<number>`COUNT(*)::int`,
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})
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.from(redPacketDraws)
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.where(
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sql`${redPacketDraws.redPacketId} = ${redPacketId}
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AND ${redPacketDraws.userId} = ${userId}`
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)
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if (count >= (packet.maxDrawTimes ?? 1)) {
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return { ok: false, message: "已达到最大抽取次数" }
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}
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/* 4️⃣ 计算剩余金额 */
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const [{ usedAmount }] = await tx
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.select({
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usedAmount: sql<string>`COALESCE(SUM(amount), 0)`,
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})
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.from(redPacketDraws)
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.where(eq(redPacketDraws.redPacketId, redPacketId))
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const precision = packet.currencyPrecision;
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const rule = packet.rule
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let amount: string
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/* 5️⃣ 金额计算（关键） */
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if (rule.type === "fixed") {
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amount = formatAmount(rule.singleAmount, precision)
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} else if (rule.type === "random") {
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const minInt = parseAmountToInt(rule.min, precision)
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const maxInt = parseAmountToInt(rule.max, precision)
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if (minInt < 0n || maxInt < 0n) {
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throw new Error("Invalid min/max: negative amount")
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}
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if (minInt > maxInt) {
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throw new Error("Invalid min/max: min > max")
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}
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const amountInt = randomBigInt(minInt, maxInt)
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amount = formatAmountFromInt(amountInt, precision)
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} else {
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// 拼手气
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const totalInt = parseAmountToInt(rule.totalAmount, precision)
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const usedInt = parseAmountToInt(usedAmount, precision)
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const remainInt = totalInt - usedInt
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if (remainInt < 0n) {
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throw new Error("Invalid state: remaining amount < 0")
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}
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let amountInt: bigint
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if (remainingCount === 1) {
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amountInt = remainInt
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} else {
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const count = BigInt(remainingCount)
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const MIN_UNIT = 1n // 1 分 / 1 sat / 1 最小单位
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// max = (remain / remainingCount) * 2
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const maxInt = (remainInt / count) * 2n
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if (maxInt < MIN_UNIT) {
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// 剩余过小，防御性兜底
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amountInt = MIN_UNIT
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} else {
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amountInt = randomBigInt(MIN_UNIT, maxInt)
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}
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}
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if (amountInt < 0n) {
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throw new Error("Invalid amount: negative")
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}
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if (amountInt > remainInt) {
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throw new Error("Invalid amount: exceeds remaining")
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}
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amount = formatAmountFromInt(amountInt, precision)
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}
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/* 6️⃣ 写入抽取记录 */
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await tx.insert(redPacketDraws).values({
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id: randomUUID(),
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redPacketId,
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userId,
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amount,
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})
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return { ok: true, amount }
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})
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} |