pragma solidity ^0.5.17;

import "./Escrow.sol";
import "../locked/ILockedSOV.sol";

/**
 *  @title A reward distribution contract for Sovryn Ethereum Pool Escrow Contract.
 *  @author Franklin Richards - powerhousefrank@protonmail.com
 *  @notice Multisig can use this contract for depositing of Reward tokens based on the total token deposit.
 */
contract EscrowReward is Escrow {
	using SafeMath for uint256;

	/* Storage */

	/// @notice The total reward tokens deposited.
	/// @dev Used for calculating the reward % share of users related to total deposit.
	uint256 public totalRewardDeposit;

	/// @notice The Locked SOV contract.
	ILockedSOV public lockedSOV;

	/* Events */

	/// @notice Emitted when the Locked SOV Contract address is updated.
	/// @param _initiator The address which initiated this event to be emitted.
	/// @param _lockedSOV The address of the Locked SOV Contract.
	event LockedSOVUpdated(address indexed _initiator, address indexed _lockedSOV);

	/// @notice Emitted when a new reward token deposit is done by Multisig.
	/// @param _initiator The address which initiated this event to be emitted.
	/// @param _amount The amount of token deposited.
	event RewardDepositByMultisig(address indexed _initiator, uint256 _amount);

	/// @notice Emitted when a Reward token withdraw is done by User.
	/// @param _initiator The address which initiated this event to be emitted.
	/// @param _amount The amount of token withdrawed.
	event RewardTokenWithdraw(address indexed _initiator, uint256 _amount);

	/* Functions */

	/**
	 * @notice Setup the required parameters.
	 * @param _lockedSOV The Locked SOV Contract address.
	 * @param _SOV The SOV token address.
	 * @param _multisig The owner of the tokens & contract.
	 * @param _releaseTime The token release time, zero if undecided.
	 * @param _depositLimit The amount of tokens we will be accepting.
	 */
	constructor(
		address _lockedSOV,
		address _SOV,
		address _multisig,
		uint256 _releaseTime,
		uint256 _depositLimit
	) public Escrow(_SOV, _multisig, _releaseTime, _depositLimit) {
		if (_lockedSOV != address(0)) {
			lockedSOV = ILockedSOV(_lockedSOV);
		}
	}

	/**
	 * @notice Set the Locked SOV Contract Address if not already done.
	 * @param _lockedSOV The Locked SOV Contract address.
	 */
	function updateLockedSOV(address _lockedSOV) external onlyMultisig {
		require(_lockedSOV != address(0), "Invalid Reward Token Address.");

		lockedSOV = ILockedSOV(_lockedSOV);

		emit LockedSOVUpdated(msg.sender, _lockedSOV);
	}

	/**
	 * @notice Deposit tokens to this contract by the Multisig.
	 * @param _amount the amount of tokens deposited.
	 * @dev The contract has to be approved by the multisig inorder for this function to work.
	 */
	function depositRewardByMultisig(uint256 _amount) external onlyMultisig {
		require(status != Status.Withdraw, "Reward Token deposit is only allowed before User Withdraw starts.");
		require(_amount > 0, "Amount needs to be bigger than zero.");

		bool txStatus = SOV.transferFrom(msg.sender, address(this), _amount);
		require(txStatus, "Token transfer was not successful.");

		totalRewardDeposit = totalRewardDeposit.add(_amount);
		txStatus = SOV.approve(address(lockedSOV), totalRewardDeposit);
		require(txStatus, "Token Approval was not successful.");

		emit RewardDepositByMultisig(msg.sender, _amount);
	}

	/**
	 * @notice Withdraws token and reward from the contract by User. Reward is gone to lockedSOV contract for future vesting.
	 * @dev Only works after the contract state is in Withdraw.
	 */
	function withdrawTokensAndReward() external checkRelease checkStatus(Status.Withdraw) {
		// Reward calculation have to be done initially as the User Balance is zeroed out .
		uint256 reward = userBalances[msg.sender].mul(totalRewardDeposit).div(totalDeposit);
		withdrawTokens();

		lockedSOV.depositSOV(msg.sender, reward);

		emit RewardTokenWithdraw(msg.sender, reward);
	}

	/* Getter Functions */

	/**
	 * @notice Function to read the reward a particular user can get.
	 * @param _addr The address of the user whose reward is to be read.
	 * @return reward The reward received by the user.
	 */
	function getReward(address _addr) external view returns (uint256 reward) {
		if (userBalances[_addr].mul(totalRewardDeposit) == 0) {
			return 0;
		}
		return userBalances[_addr].mul(totalRewardDeposit).div(totalDeposit);
	}
}