Add season2 contracts and challenge pages

packages/hardhat/contracts/INFTFlags.sol

@@ -3,4 +3,8 @@ pragma solidity >=0.8.0 <0.9.0;
 
 interface INFTFlags {
     function mint(address _recipient, uint256 _challengeId) external;
+
+    function hasMinted(address _recipient, uint256 _challengeId) external view returns (bool);
+
+    function tokenIdCounter() external view returns (uint256);
 }

packages/hardhat/contracts/Challenge1.sol → packages/hardhat/contracts/S1/Season1Challenge1.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge1 {
+contract Season1Challenge1 {
     address public nftContract;
     mapping(address => string) public builderNames;
 

packages/hardhat/contracts/Challenge11.sol → packages/hardhat/contracts/S1/Season1Challenge11.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge11 {
+contract Season1Challenge11 {
     address public nftContract;
 
     constructor(address _nftContract) {

packages/hardhat/contracts/Challenge12.sol → packages/hardhat/contracts/S1/Season1Challenge12.sol

@@ -1,10 +1,10 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./RLPReader.sol";
-import "./INFTFlags.sol";
+import "../RLPReader.sol";
+import "../INFTFlags.sol";
 
-contract Challenge12 {
+contract Season1Challenge12 {
     using RLPReader for RLPReader.RLPItem;
     using RLPReader for bytes;
 

packages/hardhat/contracts/Challenge2.sol → packages/hardhat/contracts/S1/Season1Challenge2.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge2 {
+contract Season1Challenge2 {
     address public nftContract;
 
     constructor(address _nftContract) {

packages/hardhat/contracts/Challenge3.sol → packages/hardhat/contracts/S1/Season1Challenge3.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge3 {
+contract Season1Challenge3 {
     address public nftContract;
 
     constructor(address _nftContract) {

packages/hardhat/contracts/Challenge4.sol → packages/hardhat/contracts/S1/Season1Challenge4.sol

@@ -4,9 +4,9 @@ pragma solidity >=0.8.0 <0.9.0;
 import "@openzeppelin/contracts/access/Ownable.sol";
 import "@openzeppelin/contracts/utils/cryptography/MessageHashUtils.sol";
 import "@openzeppelin/contracts/utils/cryptography/ECDSA.sol";
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge4 is Ownable {
+contract Season1Challenge4 is Ownable {
     using ECDSA for bytes32;
     using MessageHashUtils for bytes32;
 

packages/hardhat/contracts/Challenge5.sol → packages/hardhat/contracts/S1/Season1Challenge5.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge5 {
+contract Season1Challenge5 {
     address public nftContract;
     mapping(address => uint256) public points;
     uint256 public constant POINTS_TO_MINT = 10;

packages/hardhat/contracts/Challenge6.sol → packages/hardhat/contracts/S1/Season1Challenge6.sol

@@ -3,13 +3,13 @@ pragma solidity >=0.8.0 <0.9.0;
 
 import "@openzeppelin/contracts/utils/Strings.sol";
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
 interface IContract6Solution {
     function name() external view returns (string memory);
 }
 
-contract Challenge6 {
+contract Season1Challenge6 {
     using Strings for uint256;
 
     address public nftContract;

packages/hardhat/contracts/Challenge7.sol → packages/hardhat/contracts/S1/Season1Challenge7.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge7Delegate {
+contract Season1Challenge7Delegate {
     address public owner;
     event OwnerChange(address indexed owner);
 
@@ -18,14 +18,14 @@ contract Challenge7Delegate {
     }
 }
 
-contract Challenge7 {
+contract Season1Challenge7 {
     address public owner;
-    Challenge7Delegate delegate;
+    Season1Challenge7Delegate delegate;
     address public nftContract;
 
     constructor(address _nftContract, address _delegateAddress, address _owner) {
         nftContract = _nftContract;
-        delegate = Challenge7Delegate(_delegateAddress);
+        delegate = Season1Challenge7Delegate(_delegateAddress);
         owner = _owner;
     }
 

packages/hardhat/contracts/Challenge9.sol → packages/hardhat/contracts/S1/Season1Challenge9.sol

@@ -1,9 +1,9 @@
 //SPDX-License-Identifier: MIT
 pragma solidity >=0.8.0 <0.9.0;
 
-import "./INFTFlags.sol";
+import "../INFTFlags.sol";
 
-contract Challenge9 {
+contract Season1Challenge9 {
     address public nftContract;
     bytes32 private password;
     uint256 private count;

packages/hardhat/contracts/NFTFlags.sol → packages/hardhat/contracts/S1/Season1NFTFlags.sol

@@ -7,7 +7,7 @@ import "@openzeppelin/contracts/utils/Strings.sol";
 import "@openzeppelin/contracts/access/Ownable.sol";
 import "@openzeppelin/contracts/utils/Base64.sol";
 
-contract NFTFlags is ERC721, IERC721Receiver, Ownable {
+contract Season1NFTFlags is ERC721, IERC721Receiver, Ownable {
     using Strings for uint256;
 
     event Enabled(address indexed caller);

packages/hardhat/contracts/S2/Season2Challenge10.sol

@@ -0,0 +1,23 @@
+//SPDX-License-Identifier: MIT
+pragma solidity >=0.8.0 <0.9.0;
+
+import "../INFTFlags.sol";
+
+contract Season2Challenge10 {
+    address public nftContract;
+
+    constructor(address _nftContract) {
+        nftContract = _nftContract;
+    }
+
+    function mintFlag() public {
+        require(msg.sender != tx.origin, "Same address");
+        uint8 senderLast = uint8(abi.encodePacked(msg.sender)[19]);
+        uint8 originLast = uint8(abi.encodePacked(tx.origin)[19]);
+        uint8 contractFirst = uint8(abi.encodePacked(address(this))[0]);
+        uint8 senderFirst = uint8(abi.encodePacked(msg.sender)[0]);
+        require((senderLast & 0xF) == (originLast & 0xF), "Wrong sender/origin address");
+        require((senderFirst & 0xF0) == (contractFirst & 0xF0), "Wrong sender/contract address");
+        INFTFlags(nftContract).mint(tx.origin, 10);
+    }
+}

packages/hardhat/contracts/S2/Season2Challenge11.sol

@@ -0,0 +1,50 @@
+//SPDX-License-Identifier: MIT
+pragma solidity >=0.8.0 <0.9.0;
+
+import "../RLPReader.sol";
+import "../INFTFlags.sol";
+
+contract Season2Challenge11 {
+    using RLPReader for RLPReader.RLPItem;
+    using RLPReader for bytes;
+
+    address public nftContract;
+    mapping(address => uint256) public blockNumber;
+    mapping(address => uint256) public counts;
+    mapping(uint256 => bool) public blocks;
+
+    uint256 public constant futureBlocks = 2;
+
+    constructor(address _nftContract) {
+        nftContract = _nftContract;
+    }
+
+    function preMintFlag() public {
+        require(blocks[block.number] == false, "Block already used");
+        blocks[block.number] = true;
+        blockNumber[msg.sender] = block.number;
+        counts[msg.sender] += 1;
+    }
+
+    function mintFlag(bytes memory rlpBytes) public {
+        require(blockNumber[msg.sender] != 0, "PreMintFlag first");
+        require(block.number >= blockNumber[msg.sender] + futureBlocks, "Future block not reached.");
+        require(block.number < blockNumber[msg.sender] + futureBlocks + 256, "You miss the window. PreMintFlag again.");
+
+        RLPReader.RLPItem[] memory ls = rlpBytes.toRlpItem().toList();
+
+        uint256 blockNumberFromHeader = ls[8].toUint();
+
+        require(blockNumberFromHeader == blockNumber[msg.sender] + futureBlocks, "Wrong block");
+
+        require(blockhash(blockNumberFromHeader) == keccak256(rlpBytes), "Wrong block header");
+
+        bytes memory mixHash = ls[13].toBytes();
+
+        uint256 random = uint256(keccak256(abi.encodePacked(mixHash, address(this), msg.sender))) % 10;
+
+        require(random < counts[msg.sender], "Not enough pre-mints");
+
+        INFTFlags(nftContract).mint(msg.sender, 11);
+    }
+}