# Blind Box Purchase Contract

Blind Boxes will contain cards with levels vary from 1 to 5. You will get 1 S-NFT card for every blind box purchased. The level of the card will be determined by a ramdon function. 

```
function buyBoxes(uint256 boxesLength, uint256 tokenId)
        external
        payable
        nonReentrant
    {
        require(boxesLength > 0, "Boxes length must > 0");
        require(boxesLength <= 100, "Boxes length must <= 100");
        require(getBoxesLeftSupply() >= boxesLength, "Not enough boxes supply");
    
    uint256 price = boxesLength * boxTokenPrices[tokenId];
    if (tokenId == 0) {
        require(msg.value == price, "Price mismatch");
        payable(receivingAddress).transfer(price);
    } else {
        IERC20 token = IERC20(tokenAddrs[tokenId]);
        token.transferFrom(msg.sender, receivingAddress, price);
    }

    spawnHns(msg.sender, boxesLength);

    userBoxesLength[msg.sender] += boxesLength;
    userTokenBuyAmount[msg.sender][tokenId] += price;
    totalBoxesLength += boxesLength;
    totalTokenBuyAmount[tokenId] += price;
    users.add(msg.sender);
}
```

View full code at: <https://github.com/HashlandGamefi/hashland-core/blob/main/contracts/pool/HNBox.sol>


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