After Class Assignment

Auction.sol

@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-3.0
+
+pragma solidity >=0.8.2 <0.9.0;
+
+contract Auction {
+
+    address public owner;
+    uint public start;
+    uint public end;
+    uint public highestBid = 0;
+    address public highestBidder;
+    uint public previousHighestBid = 0;
+    bool public cancel = false;
+
+    //constructor(uint days) {
+    constructor(uint mins) {
+        owner = msg.sender;
+        //start = toTimestamp(14, 12, 2023, 0, 0) + 5 hours;
+        //end = toTimestamp(14, 12, 2023, 13, 0) + 5 hours;
+        start = block.timestamp;
+        end = block.timestamp + mins * 1 minutes;
+        //end = block.timestamp + days * 1 days;
+    }
+
+    modifier onlyOwner() {
+        require(msg.sender == owner, "You do not have permission to call this function");
+        _;
+    }
+
+    modifier validTime() {
+        //require(block.timestamp >= start && block.timestamp <= end, "Auction is not active");
+        require(block.timestamp >= start, "Auction has not started");
+        require(block.timestamp <= end, "Auction has ended");
+        _;
+    }
+
+    function getCurrentTime() public view returns (uint) {
+        return block.timestamp;
+    }
+
+    // Function to convert human-readable date to Unix timestamp
+    function toTimestamp(uint day, uint month, uint year, uint hour, uint minute) public pure returns (uint) {
+        return
+            (year - 1970) * 365 days +
+            (year - 1969) / 4 days -
+            (year - 1901) / 100 days +
+            (year - 1601) / 400 days +
+            (month * 306001) / 10000 +
+            day * 86400 +
+            hour * 3600 +
+            minute * 60;
+    }
+
+    //Cancel auction, only owner has the right. 
+    function cancelAuction() public onlyOwner validTime{
+        cancel = true;
+        end = block.timestamp;
+        highestBindingBid = 0;
+        highestBidder = address(0);
+    }
+
+    mapping(address => uint) public bids;
+    uint public numberOfBids;
+    address[] public highestBidders;
+    uint public l = highestBidders.length;
+
+    /*function placeBid() payable public validTime{
+        require(msg.sender != owner, "Owner can not bid in their own auction");
+        require(msg.value > 0, "Invalid value for bidding");
+        require(msg.value >= highestBid, "Invalid bid, a higher bid exists");
+        previousHighestBid = highestBid;
+        highestBid = msg.value;
+        highestBidder = msg.sender;
+        if(bids[msg.sender] > 0){
+            payable(msg.sender).transfer(bids[msg.sender]);
+        }
+        bids[msg.sender] = msg.value;
+        numberOfBids++;
+    }*/
+
+    function placeBid() payable public validTime {
+        require(msg.sender != owner, "Owner can not bid in their own auction");
+        require(msg.value > 0, "Invalid value for bidding");
+        require(msg.value >= highestBid, "Invalid bid, a higher bid exists");
+
+        if (msg.value > highestBid) {
+            highestBidders = new address[](0);
+            highestBidders.push(msg.sender);
+            highestBid = msg.value;
+        } 
+        else if (msg.value == highestBid) {
+            highestBidders.push(msg.sender);
+        }
+
+        if (bids[msg.sender] > 0) {
+            payable(msg.sender).transfer(bids[msg.sender]);
+        }
+
+        bids[msg.sender] = msg.value;
+        numberOfBids++;
+    }
+
+
+    uint public highestBindingBid;
+
+    uint public increment; 
+
+    /*function finalizeAuction() public onlyOwner{
+        require(cancel == false, "Auction has been cancelled");
+        require(block.timestamp >= end, "Auction is still in progress");
+        require(numberOfBids > 0, "No bids available");
+        increment = (highestBid-previousHighestBid)/2;
+        highestBindingBid = previousHighestBid + increment;
+        payable(owner).transfer(highestBindingBid);
+    }*/
+
+    function finalizeAuction() public onlyOwner {
+        require(cancel == false, "Auction has been cancelled");
+        require(block.timestamp >= end, "Auction is still in progress");
+        require(numberOfBids > 0, "No bids available");
+
+        //uint pseudoRandom = uint(keccak256(abi.encodePacked(block.difficulty, block.timestamp, highestBidders)));
+        uint pseudoRandom = uint(keccak256(abi.encodePacked(block.timestamp, highestBidders.length)));
+        uint selectedBidderIndex = pseudoRandom % highestBidders.length-1;
+        address selectedBidder = highestBidders[selectedBidderIndex];
+
+        payable(owner).transfer(bids[selectedBidder]);
+
+        highestBidder = selectedBidder;
+    }
+
+
+    function withdrawAmount() public {
+        require(block.timestamp >= end, "Auction is still in progress");
+        require(bids[msg.sender] > 0, "No bid to withdraw");
+        require(msg.sender != highestBidder, "You are the winner");
+        //if(msg.sender == highestBidder) {
+            //payable(msg.sender).transfer(bids[msg.sender]-highestBindingBid);
+            //bids[msg.sender] = 0;
+        //}
+        //else {
+            payable(msg.sender).transfer(bids[msg.sender]);
+            bids[msg.sender] = 0;
+        //}
+    }
+
+}