Merge pull request #49 from OpenSTFoundation/airdrop

Airdrop Contract

contracts/Airdrop.sol

@@ -0,0 +1,168 @@
+/* solhint-disable-next-line compiler-fixed */
+pragma solidity ^0.4.17;
+
+// Copyright 2018 OpenST Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// ----------------------------------------------------------------------------
+// Utility chain: Airdrop
+//
+// http://www.simpletoken.org/
+//
+// ----------------------------------------------------------------------------
+
+import "./Workers.sol";
+import "./Pricer.sol";
+
+
+contract Airdrop is Pricer {
+
+    /*
+     *  Events
+    */
+    /// Emit AirdropPayment Event
+    event AirdropPayment(
+        address indexed _beneficiary,
+        uint256 _tokenAmount,
+        address indexed _commissionBeneficiary,
+        uint256 _commissionTokenAmount,
+        bytes3 _currency,
+        uint256 _actualPricePoint,
+        address indexed _spender,
+        uint256 _airdropAmount
+        );
+
+    /*
+     *  Storage
+     */
+    Workers public workers;
+    address public airdropBudgetHolder;
+
+    /*
+      *  Constructor
+     */
+    /// @dev    Takes _brandedToken, _baseCurrency, _workers, _airdropBudgetHolder;
+    ///         constructor;
+    ///         public method;
+    /// @param _brandedToken Branded Token
+    /// @param _baseCurrency Base Currency
+    /// @param _workers  Workers contract address
+    /// @param _airdropBudgetHolder Airdrop Budget Holder Address
+    function Airdrop(
+        address _brandedToken,
+        bytes3 _baseCurrency,
+        Workers _workers,
+        address _airdropBudgetHolder)
+        public
+        Pricer(_brandedToken, _baseCurrency)
+        OpsManaged()
+    {
+        require(_workers != address(0));
+        require(airdropBudgetHolder != address(0));
+
+        workers = _workers;
+        airdropBudgetHolder = _airdropBudgetHolder;
+    }
+
+    /*
+     *  External functions
+     */
+    /// payAirdrop matches the behaviour of Pricer:pay with extra functionality of airdrop evaluation
+    /// @param _beneficiary beneficiary
+    /// @param _transferAmount transferAmount
+    /// @param _commissionBeneficiary commissionBeneficiary
+    /// @param _commissionAmount commissionAmount
+    /// @param _currency currency
+    /// @param _intendedPricePoint intendedPricePoint
+    /// @param _spender spender
+    /// @param _airdropAmount airdropAmount
+    /// @return uint256 totalPaid
+    function payAirdrop(
+        address _beneficiary,
+        uint256 _transferAmount,
+        address _commissionBeneficiary,
+        uint256 _commissionAmount,
+        bytes3 _currency,
+        uint256 _intendedPricePoint,
+        address _spender,
+        uint256 _airdropAmount)
+        public
+        returns (
+            uint256 /* totalPaid */)
+    {
+        require(workers.isWorker(msg.sender));
+        require(_spender != address(0));
+
+        require(isValidBeneficiaryData(_beneficiary, _transferAmount,
+            _commissionBeneficiary, _commissionAmount));
+
+        uint256 tokenAmount = _transferAmount;
+        uint256 commissionTokenAmount = _commissionAmount;
+        uint256 pricePoint = _intendedPricePoint;
+
+        // check Margin And Calculate BTAmount
+        if (_currency != "") {
+            (pricePoint, tokenAmount, commissionTokenAmount) = validateMarginAndCalculateBTAmount(_currency,
+                _intendedPricePoint, _transferAmount, _commissionAmount);
+        }
+
+        require(performAirdropTransferToSpender(_spender, _airdropAmount,
+            tokenAmount, commissionTokenAmount));
+        require(performTransfers(_spender, _beneficiary, tokenAmount,
+            _commissionBeneficiary, commissionTokenAmount));
+
+        /// Emit AirdropPayment Event
+        AirdropPayment(_beneficiary, tokenAmount, _commissionBeneficiary,
+            commissionTokenAmount, _currency, pricePoint, _spender, _airdropAmount);
+
+        return ((tokenAmount + commissionTokenAmount));
+    }
+
+    /*
+     *  Private functions
+     */
+    /// @dev    Takes _spender, _airdropAmount, _tokenAmount, _commissionTokenAmount;
+    ///         Calculate airdropUsed to transfer
+    ///         Perform perform Airdrop Transfer To Spender
+    ///         internal method;
+    /// @param _spender spenderUser
+    /// @param _airdropAmount airdropAmount
+    /// @param _tokenAmount tokenAmount
+    /// @param _commissionTokenAmount commissionTokenAmount
+    /// @return uint256 airdropUsed
+    function performAirdropTransferToSpender(
+        address _spender,
+        uint256 _airdropAmount,
+        uint256 _tokenAmount,
+        uint256 _commissionTokenAmount)
+        private
+        returns (
+            bool /* boolean value */)
+    {
+        uint256 totalPaid = (_tokenAmount + _commissionTokenAmount);
+        // Find out minimum of totalPaid and _airdropAmount
+        uint256 airdropUsed = _airdropAmount;
+        if (totalPaid < airdropUsed) {
+            airdropUsed = totalPaid;
+        }
+
+        // Prefund the user from the airdrop budget holder
+        if (airdropUsed > 0) {
+            require(EIP20Interface(brandedToken()).transferFrom(airdropBudgetHolder, _spender, airdropUsed));
+        }
+
+        return true;
+    }
+
+}