added in payment requirement

contracts/SkinZNFT.sol

@@ -152,8 +152,14 @@ contract SkinZNFT is ERC721Enumerable, ReentrancyGuard, Ownable {
 
  uint256 internal max_token_id;
 
+ uint256 internal nft_cost;
+
+ bool internal allow_claims;
+
  constructor() ERC721("Skin-Z", "SKZ") Ownable() {
  max_token_id = 0;
+ nft_cost = 10000000000000000; // 0.01 ETH
+ allow_claims = false;
 
  //NOTE: if we move away from arbitrum, this needs removed!
  /*address arbsys_addr = address(0x64);
@@ -177,7 +183,18 @@ contract SkinZNFT is ERC721Enumerable, ReentrancyGuard, Ownable {
  max_token_id += data[i].count;
  }
  }
-
+ function transferFunds(address payable reciever, uint256 amount) public onlyOwner nonReentrant {
+ require(address(this).balance >= amount, "invalid transfer amount");
+ require(reciever != address(0x0), "cannot burn payments");
+ 
+ reciever.transfer(amount);
+ }
+ function enableClaims() public onlyOwner {
+ allow_claims = true;
+ }
+ function disableClaims() public onlyOwner {
+ allow_claims = false;
+ }
  // NOTE: if moving from arbitrum to another blockchain, this source of randomness would need uodated!
  // generate a random number (changes between arbitrum and ethereum mainnet!)
  function random(uint256 seed) internal view returns(uint256)
@@ -222,18 +239,33 @@ contract SkinZNFT is ERC721Enumerable, ReentrancyGuard, Ownable {
  string memory output = string(abi.encodePacked('data:application/json;base64,', json));
  return output;
  }
- function claim(uint256 tokenId) public nonReentrant {
+ function claim(uint256 tokenId) public payable nonReentrant {
+ require(allow_claims, "claims are disabled");
+ require(!_msgSender().isContract(),"smart contracts cannot mint");
  require(_unmintedSkins.length > 0, "no more skins to claim");
  require(tokenId <= max_token_id && tokenId > 0, "Invalid Token ID"); //tokenIds start from 1!
  require(!_exists(tokenId), "token already claimed");
+ require(msg.value >= nft_cost,"deposit too small");
 
- 
  _nftData[tokenId] = randomSkin(tokenId);
 
  assert(bytes(_nftData[tokenId].image).length > 0);
  assert(bytes(_nftData[tokenId].name).length > 0); 
 
-
+ 
  _safeMint(_msgSender(), tokenId);
+ if(msg.value > nft_cost)
+ {
+ payable(_msgSender()).transfer(msg.value - nft_cost);
+ }
  }
+
+ // ETH can only be sent to this wallet during claims (otherwise we revert)
+ receive() external payable {
+ revert();
+ }
+ fallback() external payable {
+ revert(); 
+ } 
+ 
 }
\ No newline at end of file

notes/Skin-Z/1. projects/SkinZNFT.sol.md

@@ -90,3 +90,12 @@ For example, say we had `SkinData[]` which contained all the NFTs to mint. If we
 
 We'll likely mint all of the "rare" NFTs early, leaving only common ones to be minted by the end. 
 
+## TODO
+
+1. Deploy to arbitrum testnet w/ testing artwork
+2. ~~Require 0.01 deposit to run claim method~~
+3. ~~Refund any excess funds deposited above 0.01 cost~~
+4. ~~allow owner to transfer ETH out of contract to target wallet~~
+5. ~~Block claims until owner flips a bool ~~
+6. ~~refund any deposits not made during a claim~~
+7. Depoy to arbitrum mainnet w/ real artwork

notes/Skin-Z/3. resources/EVM/Solidity.md

 # Solidity smart contract notes
 Solidity is the prefered language to write smart contracts in. See [[Hardhat]] for a development environment.
 
+Here is an awesome learning site: https://solidity-by-example.org/
+
 ## View vs Pure
 the `VIEW` keyword is for functions that read, but do not modify the state of the blockchian.
 the `PURE` keybword is for functions that neither read nor modify the blockchain. 
 
+## Depositing ETH to functions
+
+to allow a function to accept ETH, it needs the `payable` keyword. 
+
+ETH value transfered can be found in the `msg.value` field.
+
+## Payable addresses
+
+there is the `address` type and the `address payable` type.
+To convert an address to payable do `payable(ADDRESS_HERE)`
+
+Transfer funds with `payableaddr.transfer(amount)`; (2300 gas fee)