Voting contracts

README.md

@@ -8,7 +8,9 @@ Lesson 2. Using git (git.hsbp.org, git command, init, add, commit, pull, push, u
 
 Lesson 3. Second chapter of CryptoZombies (return, mappings, require, inheritance, import, interfaces, multi return, keccak if str
 
-Lesson 4. TBA
+Lesson 4. Voting in solidity
+
+Lesson 5. Code review and due diligence
 
 
 ## Notes

contracts/dummy_voting.sol

@@ -0,0 +1,48 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity ^0.8.13;
+
+contract Voting{
+
+    struct Vote_state {
+        bool voted;
+    }
+    
+    mapping(address => bool) private Voters;
+    uint256 nft = 0;
+    uint256 dao = 0;
+    uint256 token = 0; 
+
+    constructor() {
+      Voters[0x5B38Da6a701c568545dCfcB03FcB875f56beddC4] = false;
+    }
+
+    function vote(uint256 option) external returns (bool) {
+        require(Voters[msg.sender] == false, "Already voted or non-existent.");
+        if (option == 1) {
+            Voters[msg.sender] = true;
+            nft = nft + 1;
+            return true;
+        }
+        if (option == 2) {
+            Voters[msg.sender] = true;
+            dao = dao + 1;
+            return true;
+        }
+        if (option == 3) {
+            Voters[msg.sender] = true;
+            token = token + 1;
+            return true;
+        }
+        return false;
+    }
+
+    function result() external view returns (string memory){
+        if (nft > dao && nft > token) {
+                return "nft";}
+        else if (dao > nft && dao > token){
+                return "dao";}
+        else if (token > nft && token > dao){
+                return "token";}
+        return "couldnt decide";
+    }
+}

contracts/voting_draft.sol

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+pragma solidity ^0.8.13;
+
+contract BallotDraft {
+    struct ballotVoter {
+        uint delegateWeight;
+        bool voteSpent;
+        address delegateTo;
+        uint voteIndex;
+    }
+
+    struct Proposal {
+        bytes32 proposalName;
+        uint voteCount;
+    }
+
+    address public chairman;
+    mapping(address => ballotVoter) public ballotVoters;
+    Proposal[] public proposalsOption;
+
+    function Ballot(bytes32[] proposalNames) external {
+        chairman = msg.sender;
+        ballotVoters[chairman].delegateWeight = 1;
+        for (uint i = 0; i < proposalNames.length; i++) {
+            proposalsOption.push(Proposal({
+                proposalName: proposalNames[i] ,
+                voteCount: 0
+            }));
+        }
+    }
+
+    function giveVotingRights(address ballotVoter) external {
+        require((msg.sender == chairman) && !ballotVoters[ballotvoter].voteSpent && (ballotVoters[ballotvoter].delegateWeight == 0));
+        ballotVoters[ballotvoter].delegateWeight = 1;
+    }
+
+    function delegateTo(address to) external {
+        ballotVoter storage sender = ballotVoters[msg.sender];
+        require(!sender.voteSpent);
+        require(to != msg.sender);
+        while (ballotVoters[to].delegateTo != address(0)) {
+            to = ballotVoters[to].delegateTo;
+            require(to != msg.sender);
+        }
+
+        sender.voteSpent = true;
+        sender.delegateTo = to;
+        ballotVoter storage delegateTo = ballotVoters[to];
+        if (delegateTo.voteSpent) {
+            proposalsOption[delegateTo.voteIndex].voteCount += sender.delegateWeight;
+        } else {
+            delegateTo.delegateWeight += sender.delegateWeight;
+        }
+    }
+
+    function voteIndex(uint proposal) external {
+        ballotVoter storage sender = ballotVoters[msg.sender];
+        require(!sender.voteSpent);
+        sender.voteSpent = true;
+        sender.voteIndex = proposal;
+        proposalsOption[proposal].voteCount += sender.delegateWeight;
+    }
+
+    function winnerProposal() external returns (uint winnerProposal) {
+        uint winnerVoteCount = 0;
+        for (uint p = 0; p < proposalsOption.length; p++) {
+            if (proposalsOption[p].voteCount > winnerVoteCount) {
+                winnerVoteCount = proposalsOption[p].voteCount;
+                winnerProposal = p;
+            }
+        }
+    }
+
+    function winner() external
+            returns (bytes32 winner)
+    {
+        winner = proposalsOption[winnerProposal()].proposalName;
+    }
+}