Merge pull request #367 from harmony-one/deposit-contract

Deposit Contract

contracts/DepositContract.sol

@@ -0,0 +1,62 @@
+pragma solidity >=0.4.22;
+
+contract DepositContract {
+    mapping(address => uint) private Stakes;
+    mapping(address => uint) private Indices;
+    address[] private accountList;
+
+    event LogNewAccount(address indexed account, uint index, uint stake);
+    event LogUpdateStake(address indexed account, uint index,  uint stake);
+    event LogDeleteAccount(address indexed account, uint index);
+  
+    function isAccount(address account) public view returns(bool isIndeed) {
+        if(accountList.length == 0) return false;
+        return (accountList[Indices[account]] == account);
+    }
+
+    function deposit() public payable returns(uint index) {
+        if(isAccount(msg.sender)) {
+            Stakes[msg.sender] += msg.value;
+            emit LogUpdateStake(msg.sender, Indices[msg.sender], Stakes[msg.sender]);
+            return Indices[msg.sender];
+        } else {
+            Stakes[msg.sender] = msg.value;
+            Indices[msg.sender] = accountList.push(msg.sender) - 1;
+            emit LogNewAccount(msg.sender, Indices[msg.sender], Stakes[msg.sender]);
+            return accountList.length-1;
+        }
+    }
+
+    function withdraw(uint withdrawAmount) public returns (uint remainingStake) {
+        if (withdrawAmount <= Stakes[msg.sender]){
+            Stakes[msg.sender] -= withdrawAmount;
+            msg.sender.transfer(withdrawAmount);
+            if (Stakes[msg.sender] == 0) { //If all stake has been withdrawn, remove the Account.
+                deleteAccount(msg.sender);
+            }
+            return Stakes[msg.sender];
+        } else {
+            return Stakes[msg.sender];  //Overdraft protection, no money is withdrawn!
+        }        
+    }
+  
+    function deleteAccount(address account) public returns(uint index) {
+      	//Move the last index to deleted index.
+        uint indexToDelete = Indices[account];
+        address lastIndexAddress = accountList[accountList.length-1];
+        accountList[indexToDelete] = lastIndexAddress;
+        Indices[lastIndexAddress] = indexToDelete; 
+        accountList.length--;
+        emit LogDeleteAccount(account,indexToDelete);
+        emit LogUpdateStake(lastIndexAddress, indexToDelete, Stakes[lastIndexAddress]);
+        return indexToDelete;
+    }
+
+    function getAccountCount() public view returns(uint count) {
+        return accountList.length;
+    }
+
+    function getStakedAccountList() public view returns(address[] memory stakedAccountList) {
+        return accountList;
+    }
+}