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// JACKZ.AI Fair Verify v1：Node.js 18 以上，只用內建模組
import { createHash, createHmac } from "node:crypto";

const SPACE = 2n ** 32n;

// 抽之前公開：SHA-256(Server Seed)，十六進制小寫
export function seedHash(serverSeed) {
  return createHash("sha256").update(serverSeed, "utf8").digest("hex");
}

// 第 draw 抽的 Roll：0 至 4,294,967,295
export function roll(serverSeed, clientSeed, nonce, draw = 0) {
  const block = createHmac("sha256", serverSeed)
    .update(`${clientSeed}:${nonce}:${Math.floor(draw / 8)}`)
    .digest();
  return BigInt(block.readUInt32BE((draw % 8) * 4));
}

// Threshold：Roll 小於 threshold 就成功
export function isSuccess(r, threshold) {
  return r < BigInt(threshold);
}

// 卡牌合成的 threshold；金額用十進制字串，避免浮點誤差
export function upgradeThreshold(inputValue, targetPrice, edgeRate) {
  if (!/^0(\.\d+)?$/.test(edgeRate ?? "")) throw new Error("edge_rate 必填，要是 0 至小於 1 的小數；沒有抽成填 0");
  if (![inputValue, targetPrice].every((s) => /^\d+(\.\d+)?$/.test(s ?? ""))) throw new Error("市價要用十進制數字");
  const frac = (s) => {
    const [i, f = ""] = String(s).split(".");
    return [BigInt(i + f), 10n ** BigInt(f.length)];
  };
  const [a, ad] = frac(inputValue), [t, td] = frac(targetPrice), [e, ed] = frac(edgeRate);
  return (a * (ed - e) * SPACE * td) / (ad * ed * t);
}

// Pick：weights 是各獎項的整數權重（一番賞填各賞剩餘張數），回傳獎項編號
export function pick(r, weights) {
  const w = weights.map(BigInt);
  const ticket = (r * w.reduce((x, y) => x + y, 0n)) / SPACE;
  let cum = 0n;
  for (let i = 0; i < w.length; i++) {
    cum += w[i];
    if (ticket < cum) return i;
  }
  throw new Error("weights 的總和必須大於 0");
}

// 一鍵驗證連結（Link Format v1）
export function verifyLink(base, params) {
  return `${base}#${new URLSearchParams({ v: "1", ...params })}`;
}

# JACKZ.AI Fair Verify v1：Python 3.8 以上，只用標準庫
import hashlib
import hmac
import re
from fractions import Fraction
from math import floor
from urllib.parse import urlencode

SPACE = 2 ** 32


def seed_hash(server_seed: str) -> str:
    """抽之前公開：SHA-256(Server Seed)，十六進制小寫"""
    return hashlib.sha256(server_seed.encode()).hexdigest()


def roll(server_seed: str, client_seed: str, nonce: int, draw: int = 0) -> int:
    """第 draw 抽的 Roll：0 至 4,294,967,295"""
    message = f"{client_seed}:{nonce}:{draw // 8}".encode()
    block = hmac.new(server_seed.encode(), message, hashlib.sha256).digest()
    offset = (draw % 8) * 4
    return int.from_bytes(block[offset:offset + 4], "big")


def is_success(r: int, threshold: int) -> bool:
    """Threshold：Roll 小於 threshold 就成功"""
    return r < threshold


def upgrade_threshold(input_value: str, target_price: str, edge_rate: str) -> int:
    """卡牌合成的 threshold；金額用十進制字串，避免浮點誤差"""
    if not re.fullmatch(r"0(\.\d+)?", edge_rate or ""):
        raise ValueError("edge_rate 必填，要是 0 至小於 1 的小數；沒有抽成填 0")
    if not all(re.fullmatch(r"\d+(\.\d+)?", s or "") for s in (input_value, target_price)):
        raise ValueError("市價要用十進制數字")
    return floor(Fraction(input_value) * (1 - Fraction(edge_rate)) * SPACE / Fraction(target_price))


def pick(r: int, weights: list) -> int:
    """Pick：weights 是各獎項的整數權重（一番賞填各賞剩餘張數），回傳獎項編號"""
    ticket = r * sum(weights) // SPACE
    cum = 0
    for i, w in enumerate(weights):
        cum += w
        if ticket < cum:
            return i
    raise ValueError("weights 的總和必須大於 0")


def verify_link(base: str, **params) -> str:
    """一鍵驗證連結（Link Format v1）"""
    return base + "#" + urlencode({"v": 1, **params})

<?php
// JACKZ.AI Fair Verify v1：PHP 8.5.12 或以上（64 位元），卡牌合成需要 bcmath 擴展

const FV_SPACE = 4294967296; // 2^32

// 抽之前公開：SHA-256(Server Seed)，十六進制小寫
function fv_seed_hash(string $serverSeed): string
{
    return hash('sha256', $serverSeed);
}

// 第 $draw 抽的 Roll：0 至 4,294,967,295
function fv_roll(string $serverSeed, string $clientSeed, int $nonce, int $draw = 0): int
{
    $block = hash_hmac('sha256', $clientSeed . ':' . $nonce . ':' . intdiv($draw, 8), $serverSeed, true);
    return unpack('N', substr($block, ($draw % 8) * 4, 4))[1];
}

// Threshold：Roll 小於 threshold 就成功
function fv_is_success(int $roll, int $threshold): bool
{
    return $roll < $threshold;
}

// 卡牌合成的 threshold；金額用十進制字串，需要 bcmath。edge_rate 必填，0 至小於 1，沒有抽成填 '0'
// 三個金額的小數位合共不要超過 18 位，乘積才會是準確值
function fv_upgrade_threshold(string $inputValue, string $targetPrice, string $edgeRate): string
{
    if (!preg_match('/^0(\.\d+)?$/', $edgeRate)) throw new InvalidArgumentException('edge_rate 必填，要是 0 至小於 1 的小數；沒有抽成填 0');
    foreach ([$inputValue, $targetPrice] as $s) if (!preg_match('/^\d+(\.\d+)?$/', $s)) throw new InvalidArgumentException('市價要用十進制數字');
    $n = bcmul(bcmul($inputValue, bcsub('1', $edgeRate, 18), 18), '4294967296', 18);
    return bcdiv($n, $targetPrice, 0); // scale 0 即向下取整（金額都是正數）
}

// Pick：$weights 是各獎項的整數權重（一番賞填各賞剩餘張數），回傳獎項編號
// 權重總和要小於 2^31，否則 $roll * 總和 會超出 64 位元整數，請改用 GMP 或 bcmath
function fv_pick(int $roll, array $weights): int
{
    $ticket = intdiv($roll * array_sum($weights), FV_SPACE);
    $cum = 0;
    foreach (array_values($weights) as $i => $w) {
        $cum += $w;
        if ($ticket < $cum) {
            return $i;
        }
    }
    throw new InvalidArgumentException('weights 的總和必須大於 0');
}

// 一鍵驗證連結（Link Format v1）
function fv_verify_link(string $base, array $params): string
{
    return $base . '#' . http_build_query(['v' => 1] + $params);
}