https://github.com/gamedaoio/contract/blob/master/Package.sol

pragma solidity ^0.7.0;
pragma experimental ABIEncoderV2;

// SPDX-License-Identifier: SimPL-2.0

import "./interface/IBlockhashMgr.sol";

import "./lib/String.sol";
import "./lib/Util.sol";
import "./lib/UInteger.sol";
import "./shop/Shop.sol";
import "./Card.sol";
import "./ERC721Ex.sol";

// nftSign  packageType tokenAmount quantity    padding mintTime    index
// 1        31          64          16          40      40          64
// 255      224         160         144         104     64          0

contract Package is ERC721Ex {
using String for string;
using UInteger for uint256;

struct ShopInfo {
uint256 id;
bool enabled;
}

struct PackageInfo {
uint256 blockNumber;
Shop shop;
}

//packageInfos映射
mapping(uint256 => PackageInfo) public packageInfos;

uint256 public quantityMin = 1;
uint256 public quantityMax = 50;

//shopInfos映射
mapping(address => ShopInfo) public shopInfos;
uint256 public shopCount;

constructor(string memory _name, string memory _symbol)
ERC721(_name, _symbol)
{}

function setShop(address addr, bool enable) external CheckPermit("Config") {
ShopInfo storage si = shopInfos[addr];

if (si.id == 0) {
si.id = ++shopCount;
}
si.enabled = enable;

}

function setQuantityMin(uint256 min) external CheckPermit("Config") {
quantityMin = min;
}

function setQuantityMax(uint256 max) external CheckPermit("Config") {
quantityMax = max;
}

function mint(
address to,
uint256 tokenAmount,
uint256 quantity,
uint256 padding
) external {
require(shopInfos[msg.sender].enabled, "shop not enabled");

require(
quantity >= quantityMin && quantity <= quantityMax,
"invalid quantity"
);

uint256 shopId = shopInfos[msg.sender].id;
uint256 initialAmount = tokenAmount.div(1e10);
uint256 packageId =
NFT_SIGN_BIT |
(uint256(uint32(shopId)) << 224) |
(uint256(uint64(initialAmount)) << 160) |
(uint256(uint16(quantity)) << 144) |
(uint256(uint40(padding)) << 104) |
(block.timestamp << 64) |
(uint64(totalSupply + 1));

PackageInfo storage pi = packageInfos[packageId];

pi.blockNumber = block.number + 1;
// IBlockhashMgr(manager.members("blockhashMgr"))
//     .request(pi.blockNumber);

pi.shop = Shop(msg.sender);

_mint(to, packageId);

}

function open(uint256 packageId) external {
require(
msg.sender == tokenOwners[packageId],
"you not own this package"
);

_burn(packageId);

PackageInfo storage pi = packageInfos[packageId];

// bytes32 bh = IBlockhashMgr(manager.members("blockhashMgr"))
//     .getBlockhash(pi.blockNumber);
bytes32 bh = bytes32(blockhash(pi.blockNumber));

uint256[] memory cardIdPres =
pi.shop.onOpenPackage(msg.sender, packageId, bh);

Card card = Card(manager.members("card"));
uint256 length = cardIdPres.length;

for (uint256 i = 0; i != length; ++i) {
card.mint(msg.sender, cardIdPres[i]);
}

delete packageInfos[packageId];

}

function batchOpen(uint256 packageId) external {
require(
msg.sender == tokenOwners[packageId],
"you not own this package"
);

_burn(packageId);

PackageInfo storage pi = packageInfos[packageId];

// bytes32 bh = IBlockhashMgr(manager.members("blockhashMgr"))
//     .getBlockhash(pi.blockNumber);
bytes32 bh = bytes32(blockhash(pi.blockNumber + 1));

uint256[] memory cardIdPres =
pi.shop.onOpenPackage(msg.sender, packageId, bh);

Card(manager.members("card")).batchMint(msg.sender, cardIdPres);

delete packageInfos[packageId];

}

function batchOpens(uint256[] memory packageIds) external {
uint256 length = packageIds.length;

for (uint256 i = 0; i != length; ++i) {
uint256 packageId = packageIds[i];
require(
msg.sender == tokenOwners[packageId],
"you not own this package"
);

_burn(packageId);

PackageInfo storage pi = packageInfos[packageId];

// bytes32 bh = IBlockhashMgr(manager.members("blockhashMgr"))
//     .getBlockhash(pi.blockNumber);
bytes32 bh = bytes32(blockhash(pi.blockNumber + 1));

uint256[] memory cardIdPres =
pi.shop.onOpenPackage(msg.sender, packageId, bh);

Card(manager.members("card")).batchMint(msg.sender, cardIdPres);

delete packageInfos[packageId];

}
}

function tokenURI(uint256 packageId)
external
view
override
returns (string memory)
{
PackageInfo storage pi = packageInfos[packageId];

bytes memory bs = abi.encodePacked(packageId);

uint256[] memory rarityWeights = pi.shop.getRarityWeights(packageId);

uint256 length = rarityWeights.length;
uint256 rarityWeightTotal = 0;
for (uint256 i = 0; i != length; ++i) {
rarityWeightTotal += rarityWeights[i];
}

uint256 weightMax = ~uint16(0);

for (uint256 i = 0; i != length; ++i) {
bs = abi.encodePacked(
bs,
uint16((rarityWeights[i] * weightMax) / rarityWeightTotal)
);
}

return uriPrefix.concat("package/").concat(Util.base64Encode(bs));}
}