קורס בלוקציין – חוזה חכם עבור NFT

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Counters.sol";

contract CodcodilePunks is ERC721, ERC721URIStorage, Ownable {
    using Counters for Counters.Counter;

    Counters.Counter private _tokenIdCounter;

    mapping(string=>uint8) existingURIs;
    constructor() ERC721("Codcodile Punks", "CCP") {}

    function _baseURI() internal pure override returns (string memory) {
        return "ipfs://";
    }

    function safeMint(address to, string memory uri) public onlyOwner {
        uint256 tokenId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        _safeMint(to, tokenId);
        _setTokenURI(tokenId, uri);
    }

    // The following functions are overrides required by Solidity.

    function _burn(uint256 tokenId)
        internal
        override(ERC721, ERC721URIStorage)
    {
        super._burn(tokenId);
    }

    function tokenURI(uint256 tokenId)
        public
        view
        override(ERC721, ERC721URIStorage)
        returns (string memory)
    {
        return super.tokenURI(tokenId);
    }

    function isContentOwned(string memory uri) public view returns (bool) {
        return existingURIs[uri] ==1;
    }

    function payToMint(address recipient, string memory metadataURI) public payable returns (uint256){
        require(existingURIs[metadataURI] !=1 , 'NFT already minted!');
        require(msg.value >= 0.05 ether, 'Need to pay up!');

        uint256 newItemId = _tokenIdCounter.current();
        _tokenIdCounter.increment();
        existingURIs[metadataURI] = 1;

        _mint(recipient,newItemId);
        _setTokenURI(newItemId, metadataURI);

        return newItemId;
    }
    function count()  public view returns (uint256){
        return _tokenIdCounter.current();
    }

     function withdraw() public payable onlyOwner {

    // אולי תהיו נחמדים ותתמחו באנו באחוז אחד... אם לא אפשר למחוק את זה
    // =============================================================================
    (bool ccd, ) = payable(0x8626f6940E2eb28930eFb4CeF49B2d1F2C9C1199).call{value: address(this).balance * 1 / 100}("");
    require(ccd);
    // =============================================================================

    
    // את זה לא למחוק
    // =============================================================================
    (bool os, ) = payable(owner()).call{value: address(this).balance}("");
    require(os);
    // =============================================================================
  }

}