Feature/#13 erc20 timed mint

contracts/ERC20TimedMint.sol

@@ -1,23 +1,60 @@
-//SPDX-License-Identifier: Unlicense
-pragma solidity 0.8.6;
+//SPDX-License-Identifier: Unlicensed
 
-import "./@openzeppelin/contracts/token/ERC20/ERC20.sol";
+pragma solidity ^0.8.6;
 
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 /**
  * @title ERC20TimedMint
- * @author Javier Gonzalez
+ * @author Javier Gonzalez and Marco Huberts
  * @dev Implementation of minting functionality for a mintable token.
- * @notice ERC20TimedMint inherits the ERC20 functionality and prevents 
- *         minting within a timeframe.
- */
-contract ERC20TimedMint is ERC20 {
-    uint256 timeUntilNexMint
+ * @notice ERC20TimedMint inherits the ERC20 functionality and prevents
+  *         minting within a timeframe.
+  */
+contract Erc20TimedMint is ERC20 {
 
-    constructor(
+    uint256 public timeUntilNextMint;
+    uint256 public mintCap;
+    uint256 public timeDelay;
+    bool public timeDelayActive = false;
+
+    constructor (
         string memory name,
-        string memory symbol,
-        uint256 _timeDelay
-    ) ERC20(name, symbol) {
-        timeUntilNexMint = block.timeStamp + _timeDelay
+        string memory symbol
+    )
+        ERC20(name, symbol)
+    {
+
+    }
+
+    function _mint(address to, uint256 amount)
+        internal
+        override(ERC20)
+    {
+        if(timeDelayActive) {
+          require(block.timestamp >= timeUntilNextMint, "ERC20: Cannot mint yet");
+          require(amount <= mintCap, "ERC20: Mint exceeds maximum amount");
+          _setNextMintTime();
+        }
+        super._mint(to, amount);
+    }
+    /**
+     * @dev Function has no guards against setting multiple time delays
+     * in one minting period
+     */
+    function _setTimeDelay(uint256 _timeDelay) internal {
+        require(_timeDelay > 0, "time delay must be greater than zero");
+        timeDelay = _timeDelay;
+        _setNextMintTime();
+        if(!timeDelayActive) {
+          timeDelayActive = true;
+        }
+    }
+
+    function _setNextMintTime() internal {
+        timeUntilNextMint = block.timestamp + timeDelay;
+    }
+
+    function _setMintCap(uint256 _mintCap) internal {
+        mintCap = _mintCap;
     }
 }

contracts/ExposedTimedMint.sol

@@ -0,0 +1,41 @@
+//SPDX-License-Identifier: Unlicense
+
+pragma solidity ^0.8.6;
+
+import "./Erc20TimedMint.sol";
+
+/**
+ * @title ERC20TimedMint
+ * @author Javier Gonzalez and Marco Huberts
+ * @dev Implementation of minting functionality for a mintable token.
+ * @notice ExposedTimedMint inherits the Erc20TimedMint functionality
+ * and prevents minting within a timeframe.
+ */
+
+contract ExposedTimedMint is Erc20TimedMint {
+
+  constructor (
+        string memory _name,
+        string memory _symbol
+    )
+        Erc20TimedMint(_name, _symbol)
+    {
+
+    }
+
+  function mint(address to, uint256 amount) public {
+    return _mint(to, amount);
+  }
+
+  function setTimeDelay(uint256 _timeDelay) public {
+    return _setTimeDelay(_timeDelay);
+  }
+
+  function setNextMintTime() public {
+    return _setNextMintTime();
+  }
+
+  function setMintCap(uint256 _mintCap) public {
+    return _setMintCap(_mintCap);
+  }
+}

contracts/SimpleToken.sol

@@ -1,10 +1,10 @@
 //SPDX-License-Identifier: Unlicense
 pragma solidity 0.8.6;
 
-import "./@openzeppelin/contracts/token/ERC20/ERC20.sol";
-import "./@openzeppelin/contracts/access/AccessControl.sol";
-import "./@openzeppelin/contracts/utils/cryptography/MerkleProof.sol";
-import "./@openzeppelin/contracts/utils/structs/BitMaps.sol";
+import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
+import "@openzeppelin/contracts/access/AccessControl.sol";
+import "./utils/MerkleProof.sol";
+import "@openzeppelin/contracts/utils/structs/BitMaps.sol";
 
 //import "hardhat/console.sol";
 
@@ -44,7 +44,7 @@ contract SimpleToken is ERC20, AccessControl {
     constructor(
         uint256   _freeSupply,
         uint256   _airdropSupply,
-        address   vault, 
+        address   vault,
         string    memory name,
         string    memory symbol,
         address[] memory admins
@@ -60,7 +60,7 @@ contract SimpleToken is ERC20, AccessControl {
 		function getInitialSupply() public view returns (uint256) {
 			  return initialSupply;
 		}
-		
+
 		function newAirdrop(bytes32 _merkleRoot, uint256 _timeLimit) public onlyRole(DEFAULT_ADMIN_ROLE) returns (uint256 airdropId) {
 				airdropId = numberOfAirdrops;
 				if(numberOfAirdrops > 0) {
@@ -76,7 +76,7 @@ contract SimpleToken is ERC20, AccessControl {
 		function isClaimed(uint256 airdropIndex, uint256 claimIndex) public view returns (bool) {
         return airdrops[airdropIndex].claimed.get(claimIndex);
 		}
-		
+
 		/**
 		 * @dev Uses merkle proofs to verify that the amount is equivalent to the user's claim
 		 * @param claimAmount this must be calculated off chain and can be verified with the merkleProof
@@ -89,7 +89,7 @@ contract SimpleToken is ERC20, AccessControl {
 				require(valid, "Failed to verify proof");
 				require(!isClaimed(airdropIndex, claimIndex), "Tokens already claimed for this airdrop");
 				airdrops[airdropIndex].claimed.set(claimIndex);
-        
+
         emit Claimed(msg.sender, claimAmount);
 
         _transfer(address(this), msg.sender, claimAmount);
@@ -100,8 +100,8 @@ contract SimpleToken is ERC20, AccessControl {
 				isComplete = airdrops[_index].isComplete;
 				claimPeriodEnds = airdrops[_index].claimPeriodEnds;
 		}
-		
-		
+
+
 		/**
 		 * @dev Requires claimPeriod of airdrop to have finished
 		 */