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Cover image for GameManager SmartContract deployed on XinFin XDC Network.

GameManager SmartContract deployed on XinFin XDC Network.

mahalakshmiper7 profile image MahaLakshmi Perumal ・3 min read

Deployed #solidity #smartcontract for gamemanager on the energy saving and cost efficient XinFin XDC Hybrid Blockchain Network.

Use the code:
pragma solidity ^0.4.18;
contract GameManager {
modifier onlyOwner {
require(msg.sender == owner);
_;
}
modifier onlyServer {
require(msg.sender == server);
_;
}
event GameJoined(uint indexed rounds, address indexed user, uint playerPos);
event GameStarted(uint indexed rounds, address byWhom, uint numPlayers, uint timestamp);
event GameFinalized(uint indexed rounds, address user, uint numPlayers);
event Voted(uint indexed rounds, address user, bytes32 currStateHash, bytes32 newStateHash, uint currPlayer, uint numVoted);
event ServerNeeded();
uint public currPlayerIndex;
mapping (uint => address) public userPosition;
mapping (address => bool) public usersInGame;
mapping (address => uint) public balances;
mapping (address => bool) public hasVoted;
address public owner;
bytes32 public currStateHash;
uint public numStateVerified;
bool public gameInProgress;
bool public callTheServer;
bool public playersVoted;
uint public creationTime;
address public server;
uint public submitStateStartTime;
uint public numGamesPlayed;
uint public rounds;
uint VOTE_PERIOD = 5 minutes;
uint32 ONE_PLAY = 1000;
uint FEE = 200;
uint MIN_PLAYERS = 5;
uint MAX_PLAYERS = 25;
uint PRICE_TO_ENTER = 10 ** 15;
function GameManager() public {
owner = msg.sender;
gameInProgress = false;
playersVoted = false;
callTheServer = false;
numStateVerified = 0;
creationTime = now;
currPlayerIndex = 0;
rounds = 0;
}
function joinGame() public payable {
require(msg.value >= PRICE_TO_ENTER);
// A user can't enter a game while the game is ongoing
require(gameInProgress == false);
// A user can't enter a game twice with the same address
require(usersInGame[msg.sender] == false);
// We can't have more than 25 players?
require(currPlayerIndex <= 25);
// remember which position in the array did the player get
userPosition[currPlayerIndex] = msg.sender;
usersInGame[msg.sender] = true;
// Update the current position in the array
currPlayerIndex++;
// trigger game start if we reached the required num. of players
if (currPlayerIndex >= MIN_PLAYERS) {
gameInProgress = true;
GameStarted(rounds, msg.sender, currPlayerIndex, now);
}
GameJoined(rounds, msg.sender, currPlayerIndex);
}
// What happens if some of the players don't vote??
function gameEnds(uint32[] state, uint position) public {
// The msg.sender is sending us the position where he is
require(userPosition[position] == msg.sender);
// The person who votes, must be one of the players
require(usersInGame[msg.sender] == true);
// TODO: figure out how to reset this check on game end
// A player can vote only once
//require(hasVoted[msg.sender] == false);
bytes32 stateHash = keccak256(state);
Voted(rounds, msg.sender, currStateHash, stateHash, currPlayerIndex, numStateVerified);
// we remove the user from game, so he can join in the next one
usersInGame[msg.sender] = false;
if (currStateHash == 0x0) {
currStateHash = stateHash;
submitStateStartTime = now;
numStateVerified++;
return;
}
if (currStateHash == stateHash) {
numStateVerified++;
hasVoted[msg.sender] = true;
// The last one
if (numStateVerified >= currPlayerIndex) {
playersVoted = true;
submitState(state);
}
} else {
// Bad stuff somone is cheating, server will punish the cheater and give the money to the poor
callTheServer = true;
ServerNeeded();
}
}
// Call this if after n blocks not all players have voted
// This will be callabale by anyone and we'll reward the player for the call
function finalizeGame(uint32[] state) public {
require(now >= (submitStateStartTime + VOTE_PERIOD));
// TODO: check for rounding error && possible attacks
// If majority of the verified has votes take that as true
if (numStateVerified > (currPlayerIndex / 2)) {
bytes32 stateHash = keccak256(state);
// A user gave a wrong score
if(stateHash != currStateHash) {
return;
}
submitState(state);
// reward the player for calling this function
// gameToken.transfer(msg.sender, REWARD_FOR_FINALIZE);
} else {
// who you gonna call when a cheater appears?
callTheServer = true;
ServerNeeded();
}
}
// Somebody tried the cheat the server will punish the bad
// and reward the good
function judgment(uint32[] state) public onlyServer {
require(callTheServer == true);
submitState(state);
}
function submitState(uint32[] state) internal {
require(playersVoted == true);
for(uint i = 0; i < currPlayerIndex; ++i) {
balances[userPosition[i]] += state[i];
usersInGame[userPosition[i]] = false;
}
numGamesPlayed++;
GameFinalized(rounds, msg.sender, currPlayerIndex);
newGameSession();
}
function withdrawWins() public {
require(balances[msg.sender] > 0);
msg.sender.transfer(balances[msg.sender]);
}
function newGameSession() internal {
gameInProgress = false;
playersVoted = false;
callTheServer = false;
numStateVerified = 0;
currPlayerIndex = 0;
currStateHash = 0x0;
rounds++;
}
function setServer(address _server) public onlyOwner {
server = _server;
}

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