Userdeposit.sol

pragma solidity 0.5.16;

interface Token {

    /// @return total amount of tokens
    function totalSupply() external view returns (uint256 supply);

    /// @param _owner The address from which the balance will be retrieved
    /// @return The balance
    function balanceOf(address _owner) external view returns (uint256 balance);

    /// @notice send `_value` token to `_to` from `msg.sender`
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return Whether the transfer was successful or not
    function transfer(address _to, uint256 _value) external returns (bool success);

    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
    /// @param _from The address of the sender
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return Whether the transfer was successful or not
    function transferFrom(address _from, address _to, uint256 _value) external returns (bool success);

    /// @notice `msg.sender` approves `_spender` to spend `_value` tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @param _value The amount of wei to be approved for transfer
    /// @return Whether the approval was successful or not
    function approve(address _spender, uint256 _value) external returns (bool success);

    /// @param _owner The address of the account owning tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @return Amount of remaining tokens allowed to spent
    function allowance(address _owner, address _spender) external view returns (uint256 remaining);

    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

    // Optionally implemented function to show the number of decimals for the token
    function decimals() external view returns (uint8 decimals);
}


contract Utils {
    enum MessageTypeId {
        None,
        BalanceProof,
        BalanceProofUpdate,
        Withdraw,
        CooperativeSettle,
        IOU,
        MSReward
    }

    /// @notice Check if a contract exists
    /// @param contract_address The address to check whether a contract is
    /// deployed or not
    /// @return True if a contract exists, false otherwise
    function contractExists(address contract_address) public view returns (bool) {
        uint size;

        assembly {
            size := extcodesize(contract_address)
        }

        return size > 0;
    }
}

contract UserDeposit is Utils {
    uint constant public withdraw_delay = 100;  // time before withdraw is allowed in blocks

    // Token to be used for the deposit
    Token public token;

    // Trusted contracts (can execute `transfer`)
    address public msc_address;
    address public one_to_n_address;

    // Total amount of tokens that have been deposited. This is monotonous and
    // doing a transfer or withdrawing tokens will not decrease total_deposit!
    mapping(address => uint256) public total_deposit;
    // Current user's balance, ignoring planned withdraws
    mapping(address => uint256) public balances;
    mapping(address => WithdrawPlan) public withdraw_plans;

    // The sum of all balances
    uint256 public whole_balance = 0;
    // Deposit limit for this whole contract
    uint256 public whole_balance_limit;

    /*
     *  Structs
     */
    struct WithdrawPlan {
        uint256 amount;
        uint256 withdraw_block;  // earliest block at which withdraw is allowed
    }

    /*
     *  Events
     */

    event BalanceReduced(address indexed owner, uint newBalance);
    event WithdrawPlanned(address indexed withdrawer, uint plannedBalance);

    /*
     *  Modifiers
     */

    modifier canTransfer() {
        require(msg.sender == msc_address || msg.sender == one_to_n_address, "unknown caller");
        _;
    }

    /*
     *  Constructor
     */

    /// @notice Set the default values for the smart contract
    /// @param _token_address The address of the token to use for rewards
    constructor(address _token_address, uint256 _whole_balance_limit)
        public
    {
        // check token contract
        require(_token_address != address(0x0), "token at address zero");
        require(contractExists(_token_address), "token has no code");
        token = Token(_token_address);
        require(token.totalSupply() > 0, "token has no total supply"); // Check if the contract is indeed a token contract
        // check and set the whole balance limit
        require(_whole_balance_limit > 0, "whole balance limit is zero");
        whole_balance_limit = _whole_balance_limit;
    }

    /// @notice Specify trusted contracts. This has to be done outside of the
    /// constructor to avoid cyclic dependencies.
    /// @param _msc_address Address of the MonitoringService contract
    /// @param _one_to_n_address Address of the OneToN contract
    function init(address _msc_address, address _one_to_n_address)
        external
    {
        // prevent changes of trusted contracts after initialization
        require(msc_address == address(0x0) && one_to_n_address == address(0x0), "already initialized");

        // check monitoring service contract
        require(_msc_address != address(0x0), "MS contract at address zero");
        require(contractExists(_msc_address), "MS contract has no code");
        msc_address = _msc_address;

        // check one to n contract
        require(_one_to_n_address != address(0x0), "OneToN at address zero");
        require(contractExists(_one_to_n_address), "OneToN has no code");
        one_to_n_address = _one_to_n_address;
    }

    /// @notice Deposit tokens. The amount of transferred tokens will be
    /// `new_total_deposit - total_deposit[beneficiary]`. This makes the
    /// function behavior predictable and idempotent. Can be called several
    /// times and on behalf of other accounts.
    /// @param beneficiary The account benefiting from the deposit
    /// @param new_total_deposit The total sum of tokens that have been
    /// deposited by the user by calling this function.
    function deposit(address beneficiary, uint256 new_total_deposit)
        external
    {
        require(new_total_deposit > total_deposit[beneficiary], "deposit not increasing");

        // Calculate the actual amount of tokens that will be transferred
        uint256 added_deposit = new_total_deposit - total_deposit[beneficiary];

        balances[beneficiary] += added_deposit;
        total_deposit[beneficiary] += added_deposit;

        // Update whole_balance, but take care against overflows.
        require(whole_balance + added_deposit >= whole_balance, "overflowing deposit");
        whole_balance += added_deposit;

        // Decline deposit if the whole balance is bigger than the limit.
        require(whole_balance <= whole_balance_limit, "too much deposit");

        // Actual transfer.
        require(token.transferFrom(msg.sender, address(this), added_deposit), "tokens didn't transfer");
    }

    /// @notice Internally transfer deposits between two addresses.
    /// Sender and receiver must be different or the transaction will fail.
    /// @param sender Account from which the amount will be deducted
    /// @param receiver Account to which the amount will be credited
    /// @param amount Amount of tokens to be transferred
    /// @return true if transfer has been done successfully, otherwise false
    function transfer(
        address sender,
        address receiver,
        uint256 amount
    )
        canTransfer()
        external
        returns (bool success)
    {
        require(sender != receiver, "sender == receiver");
        if (balances[sender] >= amount && amount > 0) {
            balances[sender] -= amount;
            balances[receiver] += amount;
            emit BalanceReduced(sender, balances[sender]);
            return true;
        } else {
            return false;
        }
    }

    /// @notice Announce intention to withdraw tokens.
    /// Sets the planned withdraw amount and resets the withdraw_block.
    /// There is only one planned withdrawal at a time, the old one gets overwritten.
    /// @param amount Maximum amount of tokens to be withdrawn
    function planWithdraw(uint256 amount)
        external
    {
        require(amount > 0, "withdrawing zero");
        require(balances[msg.sender] >= amount, "withdrawing too much");

        withdraw_plans[msg.sender] = WithdrawPlan({
            amount: amount,
            withdraw_block: block.number + withdraw_delay
        });
        emit WithdrawPlanned(msg.sender, balances[msg.sender] - amount);
    }

    /// @notice Execute a planned withdrawal
    /// Will only work after the withdraw_delay has expired.
    /// An amount lower or equal to the planned amount may be withdrawn.
    /// Removes the withdraw plan even if not the full amount has been
    /// withdrawn.
    /// @param amount Amount of tokens to be withdrawn
    function withdraw(uint256 amount)
        external
    {
        WithdrawPlan storage withdraw_plan = withdraw_plans[msg.sender];
        require(amount <= withdraw_plan.amount, "withdrawing more than planned");
        require(withdraw_plan.withdraw_block <= block.number, "withdrawing too early");
        uint256 withdrawable = min(amount, balances[msg.sender]);
        balances[msg.sender] -= withdrawable;

        // Update whole_balance, but take care against underflows.
        require(whole_balance - withdrawable <= whole_balance, "underflow in whole_balance");
        whole_balance -= withdrawable;

        emit BalanceReduced(msg.sender, balances[msg.sender]);
        delete withdraw_plans[msg.sender];

        require(token.transfer(msg.sender, withdrawable), "tokens didn't transfer");
    }

    /// @notice The owner's balance with planned withdrawals deducted
    /// @param owner Address for which the balance should be returned
    /// @return The remaining balance after planned withdrawals
    function effectiveBalance(address owner)
        external
        view
        returns (uint256 remaining_balance)
    {
        WithdrawPlan storage withdraw_plan = withdraw_plans[owner];
        if (withdraw_plan.amount > balances[owner]) {
            return 0;
        }
        return balances[owner] - withdraw_plan.amount;
    }

    function min(uint256 a, uint256 b) pure internal returns (uint256)
    {
        return a > b ? b : a;
    }
}