setup leaderboard

src/Main.sol

@@ -58,6 +58,12 @@ import {Mailbomb} from "./Mailbomb.sol";
 
 contract Main is Owned {
 
+    /// Track the number of kills for each address
+    mapping(address => uint256) public killCount;
+    /// Index the number of kills to form a basic leaderboard
+    mapping(uint256 => address) public leaderboard;
+    /// Point to the latest leaderboard update
+    uint256 public leaderboardPointer;
     /// Price of the Unaboomer ERC-721 token
     uint256 public unaboomerPrice = 0.01 ether;
     /// Price of the Mailbomb ERC-1155 token
@@ -67,7 +73,7 @@ contract Main is Owned {
     /// Mailbomb contract
     Mailbomb public mailbomb;
 
-    /// SendBomb event is for recording the results of sendBombs
+    /// SentBomb event is for recording the results of sendBombs
     /// @param from Sender of the bombs
     /// @param tokenId Unaboomer token which was targeted
     /// @param hit Whether or not the bomb killed the token or not (was a dud / already killed)
@@ -118,7 +124,7 @@ contract Main is Owned {
     /// The game stops.
     modifier missionNotCompleted {
         require(
-            unaboomer.killCount() <= (unaboomer.MAX_SUPPLY() - unaboomer.SURVIVOR_COUNT()), 
+            unaboomer.totalKillCount() <= (unaboomer.MAX_SUPPLY() - unaboomer.SURVIVOR_COUNT()), 
             "mission already completed"
         );
         _;
@@ -141,7 +147,7 @@ contract Main is Owned {
 
     /// Get BOOMR kill count (unaboomers killed)
     function unaboomersKilled() public view returns (uint256) {
-        return unaboomer.killCount();
+        return unaboomer.totalKillCount();
     }
 
     /// Get BOOMR token max supply
@@ -191,6 +197,7 @@ contract Main is Owned {
 
     /// Send N bombs to pseudo-random Unaboomer tokenIds to kill them.
     /// If the Unaboomer is already dead, the bomb is considered a dud.
+    /// Update a leaderboard with updated kill counts.
     /// @dev Pick a pseudo-random tokenID from Unaboomer contract and toggle a mapping value  
     /// @dev The likelihood of killing a boomer decreases as time goes on - i.e. more duds
     /// @param _amount Amount of bombs to send to kill Unaboomers
@@ -204,6 +211,17 @@ contract Main is Owned {
             unaboomer.die(randomBoomer);
             bool senderOwned = msg.sender == unaboomer.ownerOf(randomBoomer);
             emit SentBomb(msg.sender, randomBoomer, !dud, senderOwned);
+            if(!dud && !senderOwned) {
+                killCount[msg.sender]++;
+            }
+        }
+        uint256 kills = killCount[msg.sender];
+        address leader = leaderboard[leaderboardPointer];
+        if (kills > killCount[leader]) {
+            if (leader != msg.sender) {
+                leaderboardPointer++;
+                leaderboard[leaderboardPointer] = msg.sender;
+            }
         }
         mailbomb.explode(msg.sender, _amount);
     }

src/Unaboomer.sol

@@ -13,7 +13,7 @@ contract Unaboomer is ERC721A, Owned {
 
     uint256 public constant MAX_SUPPLY = 10000;
     uint256 public constant SURVIVOR_COUNT = 1000;
-    uint256 public killCount;
+    uint256 public totalKillCount;
     uint256 public minted;
     string public aliveURI;
     string public deadURI;
@@ -70,7 +70,7 @@ contract Unaboomer is ERC721A, Owned {
     function die(uint256 tokenId) external onlyMain {
         require(tokenId < totalSupply(), "invalid token id");
         if (tokenDead[tokenId] == false) {
-            killCount++;
+            totalKillCount++;
             tokenDead[tokenId] = true;
         }
     }

test/Unaboomer.t.sol

@@ -47,8 +47,8 @@ contract UnaboomerTest is Test {
         hoax(t1);
         main.sendBombs(40);
         assertEq(bomb.balanceOf(t1, 1), 20);
-        assertEq(boomr.killCount() > 0, true);
-        console.log(boomr.killCount());
+        assertEq(boomr.totalKillCount() > 0, true);
+        console.log(boomr.totalKillCount());
     }
 
     function testKilling() public {