/**
Support UBI! https://github.com/GoodDollar/GoodContracts
*/

pragma solidity >0.5.4;


/**
 * @title SafeMath
 * @dev Unsigned math operations with safety checks that revert on error
 */
library SafeMath {
    /**
    * @dev Multiplies two unsigned integers, reverts on overflow.
    */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b);

        return c;
    }

    /**
    * @dev Integer division of two unsigned integers truncating the quotient, reverts on division by zero.
    */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
    * @dev Subtracts two unsigned integers, reverts on overflow (i.e. if subtrahend is greater than minuend).
    */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a);
        uint256 c = a - b;

        return c;
    }

    /**
    * @dev Adds two unsigned integers, reverts on overflow.
    */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a);

        return c;
    }

    /**
    * @dev Divides two unsigned integers and returns the remainder (unsigned integer modulo),
    * reverts when dividing by zero.
    */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0);
        return a % b;
    }
}

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev give an account access to this role
     */
    function add(Role storage role, address account) internal {
        require(account != address(0));
        require(!has(role, account));

        role.bearer[account] = true;
    }

    /**
     * @dev remove an account's access to this role
     */
    function remove(Role storage role, address account) internal {
        require(account != address(0));
        require(has(role, account));

        role.bearer[account] = false;
    }

    /**
     * @dev check if an account has this role
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0));
        return role.bearer[account];
    }
}

contract PauserRole {
    using Roles for Roles.Role;

    event PauserAdded(address indexed account);
    event PauserRemoved(address indexed account);

    Roles.Role private _pausers;

    constructor () internal {
        _addPauser(msg.sender);
    }

    modifier onlyPauser() {
        require(isPauser(msg.sender));
        _;
    }

    function isPauser(address account) public view returns (bool) {
        return _pausers.has(account);
    }

    function addPauser(address account) public onlyPauser {
        _addPauser(account);
    }

    function renouncePauser() public {
        _removePauser(msg.sender);
    }

    function _addPauser(address account) internal {
        _pausers.add(account);
        emit PauserAdded(account);
    }

    function _removePauser(address account) internal {
        _pausers.remove(account);
        emit PauserRemoved(account);
    }
}

/**
 * @title Pausable
 * @dev Base contract which allows children to implement an emergency stop mechanism.
 */
contract Pausable is PauserRole {
    event Paused(address account);
    event Unpaused(address account);

    bool private _paused;

    constructor () internal {
        _paused = false;
    }

    /**
     * @return true if the contract is paused, false otherwise.
     */
    function paused() public view returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     */
    modifier whenNotPaused() {
        require(!_paused);
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     */
    modifier whenPaused() {
        require(_paused);
        _;
    }

    /**
     * @dev called by the owner to pause, triggers stopped state
     */
    function pause() public onlyPauser whenNotPaused {
        _paused = true;
        emit Paused(msg.sender);
    }

    /**
     * @dev called by the owner to unpause, returns to normal state
     */
    function unpause() public onlyPauser whenPaused {
        _paused = false;
        emit Unpaused(msg.sender);
    }
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(address from, address to, uint256 value) external returns (bool);

    function totalSupply() external view returns (uint256);

    function balanceOf(address who) external view returns (uint256);

    function allowance(address owner, address spender) external view returns (uint256);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
 * Originally based on code by FirstBlood:
 * https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 *
 * This implementation emits additional Approval events, allowing applications to reconstruct the allowance status for
 * all accounts just by listening to said events. Note that this isn't required by the specification, and other
 * compliant implementations may not do it.
 */
contract ERC20 is IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowed;

    uint256 private _totalSupply;

    /**
    * @dev Total number of tokens in existence
    */
    function totalSupply() public view returns (uint256) {
        return _totalSupply;
    }

    /**
    * @dev Gets the balance of the specified address.
    * @param owner The address to query the balance of.
    * @return An uint256 representing the amount owned by the passed address.
    */
    function balanceOf(address owner) public view returns (uint256) {
        return _balances[owner];
    }

    /**
     * @dev Function to check the amount of tokens that an owner allowed to a spender.
     * @param owner address The address which owns the funds.
     * @param spender address The address which will spend the funds.
     * @return A uint256 specifying the amount of tokens still available for the spender.
     */
    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowed[owner][spender];
    }

    /**
    * @dev Transfer token for a specified address
    * @param to The address to transfer to.
    * @param value The amount to be transferred.
    */
    function transfer(address to, uint256 value) public returns (bool) {
        _transfer(msg.sender, to, value);
        return true;
    }

    /**
     * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
     * Beware that changing an allowance with this method brings the risk that someone may use both the old
     * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
     * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     */
    function approve(address spender, uint256 value) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = value;
        emit Approval(msg.sender, spender, value);
        return true;
    }

    /**
     * @dev Transfer tokens from one address to another.
     * Note that while this function emits an Approval event, this is not required as per the specification,
     * and other compliant implementations may not emit the event.
     * @param from address The address which you want to send tokens from
     * @param to address The address which you want to transfer to
     * @param value uint256 the amount of tokens to be transferred
     */
    function transferFrom(address from, address to, uint256 value) public returns (bool) {
        _allowed[from][msg.sender] = _allowed[from][msg.sender].sub(value);
        _transfer(from, to, value);
        emit Approval(from, msg.sender, _allowed[from][msg.sender]);
        return true;
    }

    /**
     * @dev Increase the amount of tokens that an owner allowed to a spender.
     * approve should be called when allowed_[_spender] == 0. To increment
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param addedValue The amount of tokens to increase the allowance by.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = _allowed[msg.sender][spender].add(addedValue);
        emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
        return true;
    }

    /**
     * @dev Decrease the amount of tokens that an owner allowed to a spender.
     * approve should be called when allowed_[_spender] == 0. To decrement
     * allowed value is better to use this function to avoid 2 calls (and wait until
     * the first transaction is mined)
     * From MonolithDAO Token.sol
     * Emits an Approval event.
     * @param spender The address which will spend the funds.
     * @param subtractedValue The amount of tokens to decrease the allowance by.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
        require(spender != address(0));

        _allowed[msg.sender][spender] = _allowed[msg.sender][spender].sub(subtractedValue);
        emit Approval(msg.sender, spender, _allowed[msg.sender][spender]);
        return true;
    }

    /**
    * @dev Transfer token for a specified addresses
    * @param from The address to transfer from.
    * @param to The address to transfer to.
    * @param value The amount to be transferred.
    */
    function _transfer(address from, address to, uint256 value) internal {
        require(to != address(0));

        _balances[from] = _balances[from].sub(value);
        _balances[to] = _balances[to].add(value);
        emit Transfer(from, to, value);
    }

    /**
     * @dev Internal function that mints an amount of the token and assigns it to
     * an account. This encapsulates the modification of balances such that the
     * proper events are emitted.
     * @param account The account that will receive the created tokens.
     * @param value The amount that will be created.
     */
    function _mint(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.add(value);
        _balances[account] = _balances[account].add(value);
        emit Transfer(address(0), account, value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account.
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burn(address account, uint256 value) internal {
        require(account != address(0));

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    /**
     * @dev Internal function that burns an amount of the token of a given
     * account, deducting from the sender's allowance for said account. Uses the
     * internal burn function.
     * Emits an Approval event (reflecting the reduced allowance).
     * @param account The account whose tokens will be burnt.
     * @param value The amount that will be burnt.
     */
    function _burnFrom(address account, uint256 value) internal {
        _allowed[account][msg.sender] = _allowed[account][msg.sender].sub(value);
        _burn(account, value);
        emit Approval(account, msg.sender, _allowed[account][msg.sender]);
    }
}

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @return the address of the owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * @notice Renouncing to ownership will leave the contract without an owner.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

/**
 * @title Reputation system
 * @dev A DAO has Reputation System which allows peers to rate other peers in order to build trust .
 * A reputation is use to assign influence measure to a DAO'S peers.
 * Reputation is similar to regular tokens but with one crucial difference: It is non-transferable.
 * The Reputation contract maintain a map of address to reputation value.
 * It provides an onlyOwner functions to mint and burn reputation _to (or _from) a specific address.
 */
contract Reputation is Ownable {

    uint8 public decimals = 18;             //Number of decimals of the smallest unit
    // Event indicating minting of reputation to an address.
    event Mint(address indexed _to, uint256 _amount);
    // Event indicating burning of reputation for an address.
    event Burn(address indexed _from, uint256 _amount);

      /// @dev `Checkpoint` is the structure that attaches a block number to a
      ///  given value, the block number attached is the one that last changed the
      ///  value
    struct Checkpoint {

    // `fromBlock` is the block number that the value was generated from
        uint128 fromBlock;

          // `value` is the amount of reputation at a specific block number
        uint128 value;
    }

      // `balances` is the map that tracks the balance of each address, in this
      //  contract when the balance changes the block number that the change
      //  occurred is also included in the map
    mapping (address => Checkpoint[]) balances;

      // Tracks the history of the `totalSupply` of the reputation
    Checkpoint[] totalSupplyHistory;

    /// @notice Constructor to create a Reputation
    constructor(
    ) public
    {
    }

    /// @dev This function makes it easy to get the total number of reputation
    /// @return The total number of reputation
    function totalSupply() public view returns (uint256) {
        return totalSupplyAt(block.number);
    }

  ////////////////
  // Query balance and totalSupply in History
  ////////////////
    /**
    * @dev return the reputation amount of a given owner
    * @param _owner an address of the owner which we want to get his reputation
    */
    function balanceOf(address _owner) public view returns (uint256 balance) {
        return balanceOfAt(_owner, block.number);
    }

      /// @dev Queries the balance of `_owner` at a specific `_blockNumber`
      /// @param _owner The address from which the balance will be retrieved
      /// @param _blockNumber The block number when the balance is queried
      /// @return The balance at `_blockNumber`
    function balanceOfAt(address _owner, uint256 _blockNumber)
    public view returns (uint256)
    {
        if ((balances[_owner].length == 0) || (balances[_owner][0].fromBlock > _blockNumber)) {
            return 0;
          // This will return the expected balance during normal situations
        } else {
            return getValueAt(balances[_owner], _blockNumber);
        }
    }

      /// @notice Total amount of reputation at a specific `_blockNumber`.
      /// @param _blockNumber The block number when the totalSupply is queried
      /// @return The total amount of reputation at `_blockNumber`
    function totalSupplyAt(uint256 _blockNumber) public view returns(uint256) {
        if ((totalSupplyHistory.length == 0) || (totalSupplyHistory[0].fromBlock > _blockNumber)) {
            return 0;
          // This will return the expected totalSupply during normal situations
        } else {
            return getValueAt(totalSupplyHistory, _blockNumber);
        }
    }

      /// @notice Generates `_amount` reputation that are assigned to `_owner`
      /// @param _user The address that will be assigned the new reputation
      /// @param _amount The quantity of reputation generated
      /// @return True if the reputation are generated correctly
    function mint(address _user, uint256 _amount) public onlyOwner returns (bool) {
        uint256 curTotalSupply = totalSupply();
        require(curTotalSupply + _amount >= curTotalSupply); // Check for overflow
        uint256 previousBalanceTo = balanceOf(_user);
        require(previousBalanceTo + _amount >= previousBalanceTo); // Check for overflow
        updateValueAtNow(totalSupplyHistory, curTotalSupply + _amount);
        updateValueAtNow(balances[_user], previousBalanceTo + _amount);
        emit Mint(_user, _amount);
        return true;
    }

      /// @notice Burns `_amount` reputation from `_owner`
      /// @param _user The address that will lose the reputation
      /// @param _amount The quantity of reputation to burn
      /// @return True if the reputation are burned correctly
    function burn(address _user, uint256 _amount) public onlyOwner returns (bool) {
        uint256 curTotalSupply = totalSupply();
        uint256 amountBurned = _amount;
        uint256 previousBalanceFrom = balanceOf(_user);
        if (previousBalanceFrom < amountBurned) {
            amountBurned = previousBalanceFrom;
        }
        updateValueAtNow(totalSupplyHistory, curTotalSupply - amountBurned);
        updateValueAtNow(balances[_user], previousBalanceFrom - amountBurned);
        emit Burn(_user, amountBurned);
        return true;
    }

  ////////////////
  // Internal helper functions to query and set a value in a snapshot array
  ////////////////

      /// @dev `getValueAt` retrieves the number of reputation at a given block number
      /// @param checkpoints The history of values being queried
      /// @param _block The block number to retrieve the value at
      /// @return The number of reputation being queried
    function getValueAt(Checkpoint[] storage checkpoints, uint256 _block) internal view returns (uint256) {
        if (checkpoints.length == 0) {
            return 0;
        }

          // Shortcut for the actual value
        if (_block >= checkpoints[checkpoints.length-1].fromBlock) {
            return checkpoints[checkpoints.length-1].value;
        }
        if (_block < checkpoints[0].fromBlock) {
            return 0;
        }

          // Binary search of the value in the array
        uint256 min = 0;
        uint256 max = checkpoints.length-1;
        while (max > min) {
            uint256 mid = (max + min + 1) / 2;
            if (checkpoints[mid].fromBlock<=_block) {
                min = mid;
            } else {
                max = mid-1;
            }
        }
        return checkpoints[min].value;
    }

      /// @dev `updateValueAtNow` used to update the `balances` map and the
      ///  `totalSupplyHistory`
      /// @param checkpoints The history of data being updated
      /// @param _value The new number of reputation
    function updateValueAtNow(Checkpoint[] storage checkpoints, uint256 _value) internal {
        require(uint128(_value) == _value); //check value is in the 128 bits bounderies
        if ((checkpoints.length == 0) || (checkpoints[checkpoints.length - 1].fromBlock < block.number)) {
            Checkpoint storage newCheckPoint = checkpoints[checkpoints.length++];
            newCheckPoint.fromBlock = uint128(block.number);
            newCheckPoint.value = uint128(_value);
        } else {
            Checkpoint storage oldCheckPoint = checkpoints[checkpoints.length-1];
            oldCheckPoint.value = uint128(_value);
        }
    }
}

/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
contract ERC20Burnable is ERC20 {
    /**
     * @dev Burns a specific amount of tokens.
     * @param value The amount of token to be burned.
     */
    function burn(uint256 value) public {
        _burn(msg.sender, value);
    }

    /**
     * @dev Burns a specific amount of tokens from the target address and decrements allowance
     * @param from address The address which you want to send tokens from
     * @param value uint256 The amount of token to be burned
     */
    function burnFrom(address from, uint256 value) public {
        _burnFrom(from, value);
    }
}

/**
 * @title DAOToken, base on zeppelin contract.
 * @dev ERC20 compatible token. It is a mintable, burnable token.
 */
contract DAOToken is ERC20, ERC20Burnable, Ownable {

    string public name;
    string public symbol;
    // solhint-disable-next-line const-name-snakecase
    uint8 public constant decimals = 18;
    uint256 public cap;

    /**
    * @dev Constructor
    * @param _name - token name
    * @param _symbol - token symbol
    * @param _cap - token cap - 0 value means no cap
    */
    constructor(string memory _name, string memory _symbol, uint256 _cap)
    public {
        name = _name;
        symbol = _symbol;
        cap = _cap;
    }

    /**
     * @dev Function to mint tokens
     * @param _to The address that will receive the minted tokens.
     * @param _amount The amount of tokens to mint.
     */
    function mint(address _to, uint256 _amount) public onlyOwner returns (bool) {
        if (cap > 0)
            require(totalSupply().add(_amount) <= cap);
        _mint(_to, _amount);
        return true;
    }
}

/**
 * Utility library of inline functions on addresses
 */
library Address {
    /**
     * Returns whether the target address is a contract
     * @dev This function will return false if invoked during the constructor of a contract,
     * as the code is not actually created until after the constructor finishes.
     * @param account address of the account to check
     * @return whether the target address is a contract
     */
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}

/*

SafeERC20 by daostack.
The code is based on a fix by SECBIT Team.

USE WITH CAUTION & NO WARRANTY

REFERENCE & RELATED READING
- https://github.com/ethereum/solidity/issues/4116
- https://medium.com/@chris_77367/explaining-unexpected-reverts-starting-with-solidity-0-4-22-3ada6e82308c
- https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca
- https://gist.github.com/BrendanChou/88a2eeb80947ff00bcf58ffdafeaeb61

*/
library SafeERC20 {
    using Address for address;

    bytes4 constant private TRANSFER_SELECTOR = bytes4(keccak256(bytes("transfer(address,uint256)")));
    bytes4 constant private TRANSFERFROM_SELECTOR = bytes4(keccak256(bytes("transferFrom(address,address,uint256)")));
    bytes4 constant private APPROVE_SELECTOR = bytes4(keccak256(bytes("approve(address,uint256)")));

    function safeTransfer(address _erc20Addr, address _to, uint256 _value) internal {

        // Must be a contract addr first!
        require(_erc20Addr.isContract());

        (bool success, bytes memory returnValue) =
        // solhint-disable-next-line avoid-low-level-calls
        _erc20Addr.call(abi.encodeWithSelector(TRANSFER_SELECTOR, _to, _value));
        // call return false when something wrong
        require(success);
        //check return value
        require(returnValue.length == 0 || (returnValue.length == 32 && (returnValue[31] != 0)));
    }

    function safeTransferFrom(address _erc20Addr, address _from, address _to, uint256 _value) internal {

        // Must be a contract addr first!
        require(_erc20Addr.isContract());

        (bool success, bytes memory returnValue) =
        // solhint-disable-next-line avoid-low-level-calls
        _erc20Addr.call(abi.encodeWithSelector(TRANSFERFROM_SELECTOR, _from, _to, _value));
        // call return false when something wrong
        require(success);
        //check return value
        require(returnValue.length == 0 || (returnValue.length == 32 && (returnValue[31] != 0)));
    }

    function safeApprove(address _erc20Addr, address _spender, uint256 _value) internal {

        // Must be a contract addr first!
        require(_erc20Addr.isContract());

        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero.
        require((_value == 0) || (IERC20(_erc20Addr).allowance(address(this), _spender) == 0));

        (bool success, bytes memory returnValue) =
        // solhint-disable-next-line avoid-low-level-calls
        _erc20Addr.call(abi.encodeWithSelector(APPROVE_SELECTOR, _spender, _value));
        // call return false when something wrong
        require(success);
        //check return value
        require(returnValue.length == 0 || (returnValue.length == 32 && (returnValue[31] != 0)));
    }
}

/**
 * @title An Avatar holds tokens, reputation and ether for a controller
 */
contract Avatar is Ownable {
    using SafeERC20 for address;

    string public orgName;
    DAOToken public nativeToken;
    Reputation public nativeReputation;

    event GenericCall(address indexed _contract, bytes _data, uint _value, bool _success);
    event SendEther(uint256 _amountInWei, address indexed _to);
    event ExternalTokenTransfer(address indexed _externalToken, address indexed _to, uint256 _value);
    event ExternalTokenTransferFrom(address indexed _externalToken, address _from, address _to, uint256 _value);
    event ExternalTokenApproval(address indexed _externalToken, address _spender, uint256 _value);
    event ReceiveEther(address indexed _sender, uint256 _value);
    event MetaData(string _metaData);

    /**
    * @dev the constructor takes organization name, native token and reputation system
    and creates an avatar for a controller
    */
    constructor(string memory _orgName, DAOToken _nativeToken, Reputation _nativeReputation) public {
        orgName = _orgName;
        nativeToken = _nativeToken;
        nativeReputation = _nativeReputation;
    }

    /**
    * @dev enables an avatar to receive ethers
    */
    function() external payable {
        emit ReceiveEther(msg.sender, msg.value);
    }

    /**
    * @dev perform a generic call to an arbitrary contract
    * @param _contract  the contract's address to call
    * @param _data ABI-encoded contract call to call `_contract` address.
    * @param _value value (ETH) to transfer with the transaction
    * @return bool    success or fail
    *         bytes - the return bytes of the called contract's function.
    */
    function genericCall(address _contract, bytes memory _data, uint256 _value)
    public
    onlyOwner
    returns(bool success, bytes memory returnValue) {
      // solhint-disable-next-line avoid-call-value
        (success, returnValue) = _contract.call.value(_value)(_data);
        emit GenericCall(_contract, _data, _value, success);
    }

    /**
    * @dev send ethers from the avatar's wallet
    * @param _amountInWei amount to send in Wei units
    * @param _to send the ethers to this address
    * @return bool which represents success
    */
    function sendEther(uint256 _amountInWei, address payable _to) public onlyOwner returns(bool) {
        _to.transfer(_amountInWei);
        emit SendEther(_amountInWei, _to);
        return true;
    }

    /**
    * @dev external token transfer
    * @param _externalToken the token contract
    * @param _to the destination address
    * @param _value the amount of tokens to transfer
    * @return bool which represents success
    */
    function externalTokenTransfer(IERC20 _externalToken, address _to, uint256 _value)
    public onlyOwner returns(bool)
    {
        address(_externalToken).safeTransfer(_to, _value);
        emit ExternalTokenTransfer(address(_externalToken), _to, _value);
        return true;
    }

    /**
    * @dev external token transfer from a specific account
    * @param _externalToken the token contract
    * @param _from the account to spend token from
    * @param _to the destination address
    * @param _value the amount of tokens to transfer
    * @return bool which represents success
    */
    function externalTokenTransferFrom(
        IERC20 _externalToken,
        address _from,
        address _to,
        uint256 _value
    )
    public onlyOwner returns(bool)
    {
        address(_externalToken).safeTransferFrom(_from, _to, _value);
        emit ExternalTokenTransferFrom(address(_externalToken), _from, _to, _value);
        return true;
    }

    /**
    * @dev externalTokenApproval approve the spender address to spend a specified amount of tokens
    *      on behalf of msg.sender.
    * @param _externalToken the address of the Token Contract
    * @param _spender address
    * @param _value the amount of ether (in Wei) which the approval is referring to.
    * @return bool which represents a success
    */
    function externalTokenApproval(IERC20 _externalToken, address _spender, uint256 _value)
    public onlyOwner returns(bool)
    {
        address(_externalToken).safeApprove(_spender, _value);
        emit ExternalTokenApproval(address(_externalToken), _spender, _value);
        return true;
    }

    /**
    * @dev metaData emits an event with a string, should contain the hash of some meta data.
    * @param _metaData a string representing a hash of the meta data
    * @return bool which represents a success
    */
    function metaData(string memory _metaData) public onlyOwner returns(bool) {
        emit MetaData(_metaData);
        return true;
    }


}

contract GlobalConstraintInterface {

    enum CallPhase { Pre, Post, PreAndPost }

    function pre( address _scheme, bytes32 _params, bytes32 _method ) public returns(bool);
    function post( address _scheme, bytes32 _params, bytes32 _method ) public returns(bool);
    /**
     * @dev when return if this globalConstraints is pre, post or both.
     * @return CallPhase enum indication  Pre, Post or PreAndPost.
     */
    function when() public returns(CallPhase);
}

/**
 * @title Controller contract
 * @dev A controller controls the organizations tokens ,reputation and avatar.
 * It is subject to a set of schemes and constraints that determine its behavior.
 * Each scheme has it own parameters and operation permissions.
 */
interface ControllerInterface {

    /**
     * @dev Mint `_amount` of reputation that are assigned to `_to` .
     * @param  _amount amount of reputation to mint
     * @param _to beneficiary address
     * @return bool which represents a success
    */
    function mintReputation(uint256 _amount, address _to, address _avatar)
    external
    returns(bool);

    /**
     * @dev Burns `_amount` of reputation from `_from`
     * @param _amount amount of reputation to burn
     * @param _from The address that will lose the reputation
     * @return bool which represents a success
     */
    function burnReputation(uint256 _amount, address _from, address _avatar)
    external
    returns(bool);

    /**
     * @dev mint tokens .
     * @param  _amount amount of token to mint
     * @param _beneficiary beneficiary address
     * @param _avatar address
     * @return bool which represents a success
     */
    function mintTokens(uint256 _amount, address _beneficiary, address _avatar)
    external
    returns(bool);

  /**
   * @dev register or update a scheme
   * @param _scheme the address of the scheme
   * @param _paramsHash a hashed configuration of the usage of the scheme
   * @param _permissions the permissions the new scheme will have
   * @param _avatar address
   * @return bool which represents a success
   */
    function registerScheme(address _scheme, bytes32 _paramsHash, bytes4 _permissions, address _avatar)
    external
    returns(bool);

    /**
     * @dev unregister a scheme
     * @param _avatar address
     * @param _scheme the address of the scheme
     * @return bool which represents a success
     */
    function unregisterScheme(address _scheme, address _avatar)
    external
    returns(bool);

    /**
     * @dev unregister the caller's scheme
     * @param _avatar address
     * @return bool which represents a success
     */
    function unregisterSelf(address _avatar) external returns(bool);

    /**
     * @dev add or update Global Constraint
     * @param _globalConstraint the address of the global constraint to be added.
     * @param _params the constraint parameters hash.
     * @param _avatar the avatar of the organization
     * @return bool which represents a success
     */
    function addGlobalConstraint(address _globalConstraint, bytes32 _params, address _avatar)
    external returns(bool);

    /**
     * @dev remove Global Constraint
     * @param _globalConstraint the address of the global constraint to be remove.
     * @param _avatar the organization avatar.
     * @return bool which represents a success
     */
    function removeGlobalConstraint (address _globalConstraint, address _avatar)
    external  returns(bool);

  /**
    * @dev upgrade the Controller
    *      The function will trigger an event 'UpgradeController'.
    * @param  _newController the address of the new controller.
    * @param _avatar address
    * @return bool which represents a success
    */
    function upgradeController(address _newController, Avatar _avatar)
    external returns(bool);

    /**
    * @dev perform a generic call to an arbitrary contract
    * @param _contract  the contract's address to call
    * @param _data ABI-encoded contract call to call `_contract` address.
    * @param _avatar the controller's avatar address
    * @param _value value (ETH) to transfer with the transaction
    * @return bool -success
    *         bytes  - the return value of the called _contract's function.
    */
    function genericCall(address _contract, bytes calldata _data, Avatar _avatar, uint256 _value)
    external
    returns(bool, bytes memory);

  /**
   * @dev send some ether
   * @param _amountInWei the amount of ether (in Wei) to send
   * @param _to address of the beneficiary
   * @param _avatar address
   * @return bool which represents a success
   */
    function sendEther(uint256 _amountInWei, address payable _to, Avatar _avatar)
    external returns(bool);

    /**
    * @dev send some amount of arbitrary ERC20 Tokens
    * @param _externalToken the address of the Token Contract
    * @param _to address of the beneficiary
    * @param _value the amount of ether (in Wei) to send
    * @param _avatar address
    * @return bool which represents a success
    */
    function externalTokenTransfer(IERC20 _externalToken, address _to, uint256 _value, Avatar _avatar)
    external
    returns(bool);

    /**
    * @dev transfer token "from" address "to" address
    *      One must to approve the amount of tokens which can be spend from the
    *      "from" account.This can be done using externalTokenApprove.
    * @param _externalToken the address of the Token Contract
    * @param _from address of the account to send from
    * @param _to address of the beneficiary
    * @param _value the amount of ether (in Wei) to send
    * @param _avatar address
    * @return bool which represents a success
    */
    function externalTokenTransferFrom(
    IERC20 _externalToken,
    address _from,
    address _to,
    uint256 _value,
    Avatar _avatar)
    external
    returns(bool);

    /**
    * @dev externalTokenApproval approve the spender address to spend a specified amount of tokens
    *      on behalf of msg.sender.
    * @param _externalToken the address of the Token Contract
    * @param _spender address
    * @param _value the amount of ether (in Wei) which the approval is referring to.
    * @return bool which represents a success
    */
    function externalTokenApproval(IERC20 _externalToken, address _spender, uint256 _value, Avatar _avatar)
    external
    returns(bool);

    /**
    * @dev metaData emits an event with a string, should contain the hash of some meta data.
    * @param _metaData a string representing a hash of the meta data
    * @param _avatar Avatar
    * @return bool which represents a success
    */
    function metaData(string calldata _metaData, Avatar _avatar) external returns(bool);

    /**
     * @dev getNativeReputation
     * @param _avatar the organization avatar.
     * @return organization native reputation
     */
    function getNativeReputation(address _avatar)
    external
    view
    returns(address);

    function isSchemeRegistered( address _scheme, address _avatar) external view returns(bool);

    function getSchemeParameters(address _scheme, address _avatar) external view returns(bytes32);

    function getGlobalConstraintParameters(address _globalConstraint, address _avatar) external view returns(bytes32);

    function getSchemePermissions(address _scheme, address _avatar) external view returns(bytes4);

    /**
     * @dev globalConstraintsCount return the global constraint pre and post count
     * @return uint256 globalConstraintsPre count.
     * @return uint256 globalConstraintsPost count.
     */
    function globalConstraintsCount(address _avatar) external view returns(uint, uint);

    function isGlobalConstraintRegistered(address _globalConstraint, address _avatar) external view returns(bool);
}

/* @dev abstract contract for ensuring that schemes have been registered properly
 * Allows setting zero Avatar in situations where the Avatar hasn't been created yet
 */
contract SchemeGuard is Ownable {
    Avatar avatar;
    ControllerInterface internal controller = ControllerInterface(0);

    /** @dev Constructor. only sets controller if given avatar is not null.
     * @param _avatar The avatar of the DAO.
     */
    constructor(Avatar _avatar) public {
        avatar = _avatar;

        if (avatar != Avatar(0)) {
            controller = ControllerInterface(avatar.owner());
        }
    }

    /** @dev modifier to check if caller is avatar
     */
    modifier onlyAvatar() {
        require(address(avatar) == msg.sender, "only Avatar can call this method");
        _;
    }

    /** @dev modifier to check if scheme is registered
     */
    modifier onlyRegistered() {
        require(isRegistered(), "Scheme is not registered");
        _;
    }

    /** @dev modifier to check if scheme is not registered
     */
    modifier onlyNotRegistered() {
        require(!isRegistered(), "Scheme is registered");
        _;
    }

    /** @dev modifier to check if call is a scheme that is registered
     */
    modifier onlyRegisteredCaller() {
        require(isRegistered(msg.sender), "Calling scheme is not registered");
        _;
    }

    /** @dev Function to set a new avatar and controller for scheme
     * can only be done by owner of scheme
     */
    function setAvatar(Avatar _avatar) public onlyOwner {
        avatar = _avatar;
        controller = ControllerInterface(avatar.owner());
    }

    /** @dev function to see if an avatar has been set and if this scheme is registered
     * @return true if scheme is registered
     */
    function isRegistered() public view returns (bool) {
        return isRegistered(address(this));
    }

    /** @dev function to see if an avatar has been set and if this scheme is registered
     * @return true if scheme is registered
     */
    function isRegistered(address scheme) public view returns (bool) {
        require(avatar != Avatar(0), "Avatar is not set");

        if (!(controller.isSchemeRegistered(scheme, address(avatar)))) {
            return false;
        }
        return true;
    }
}

/**
 * @title Contract managing the identity admin role
 */
contract IdentityAdminRole is Ownable {
    using Roles for Roles.Role;

    event IdentityAdminAdded(address indexed account);
    event IdentityAdminRemoved(address indexed account);

    Roles.Role private IdentityAdmins;

    /* @dev constructor. Adds caller as an admin
     */
    constructor() internal {
        _addIdentityAdmin(msg.sender);
    }

    /* @dev Modifier to check if caller is an admin
     */
    modifier onlyIdentityAdmin() {
        require(isIdentityAdmin(msg.sender), "not IdentityAdmin");
        _;
    }

    /**
     * @dev Checks if account is identity admin
     * @param account Account to check
     * @return Boolean indicating if account is identity admin
     */
    function isIdentityAdmin(address account) public view returns (bool) {
        return IdentityAdmins.has(account);
    }

    /**
     * @dev Adds a identity admin account. Is only callable by owner.
     * @param account Address to be added
     * @return true if successful
     */
    function addIdentityAdmin(address account) public onlyOwner returns (bool) {
        _addIdentityAdmin(account);
        return true;
    }

    /**
     * @dev Removes a identity admin account. Is only callable by owner.
     * @param account Address to be removed
     * @return true if successful
     */
    function removeIdentityAdmin(address account) public onlyOwner returns (bool) {
        _removeIdentityAdmin(account);
        return true;
    }

    /**
     * @dev Allows an admin to renounce their role
     */
    function renounceIdentityAdmin() public {
        _removeIdentityAdmin(msg.sender);
    }

    /**
     * @dev Internal implementation of addIdentityAdmin
     */
    function _addIdentityAdmin(address account) internal {
        IdentityAdmins.add(account);
        emit IdentityAdminAdded(account);
    }

    /**
     * @dev Internal implementation of removeIdentityAdmin
     */
    function _removeIdentityAdmin(address account) internal {
        IdentityAdmins.remove(account);
        emit IdentityAdminRemoved(account);
    }
}

/* @title Identity contract responsible for whitelisting
 * and keeping track of amount of whitelisted users
 */
contract Identity is IdentityAdminRole, SchemeGuard, Pausable {
    using Roles for Roles.Role;
    using SafeMath for uint256;

    Roles.Role private blacklist;
    Roles.Role private whitelist;
    Roles.Role private contracts;

    uint256 public whitelistedCount = 0;
    uint256 public whitelistedContracts = 0;
    uint256 public authenticationPeriod = 14;

    mapping(address => uint256) public dateAuthenticated;
    mapping(address => uint256) public dateAdded;

    mapping(address => string) public addrToDID;
    mapping(bytes32 => address) public didHashToAddress;

    event BlacklistAdded(address indexed account);
    event BlacklistRemoved(address indexed account);

    event WhitelistedAdded(address indexed account);
    event WhitelistedRemoved(address indexed account);

    event ContractAdded(address indexed account);
    event ContractRemoved(address indexed account);

    constructor() public SchemeGuard(Avatar(0)) {}

    /* @dev Sets a new value for authenticationPeriod.
     * Can only be called by Identity Administrators.
     * @param period new value for authenticationPeriod
     */
    function setAuthenticationPeriod(uint256 period) public onlyOwner whenNotPaused {
        authenticationPeriod = period;
    }

    /* @dev Sets the authentication date of `account`
     * to the current time.
     * Can only be called by Identity Administrators.
     * @param account address to change its auth date
     */
    function authenticate(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        dateAuthenticated[account] = now;
    }

    /* @dev Adds an address as whitelisted.
     * Can only be called by Identity Administrators.
     * @param account address to add as whitelisted
     */
    function addWhitelisted(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        _addWhitelisted(account);
    }

    /* @dev Adds an address as whitelisted under a specific ID
     * @param account The address to add
     * @param did the ID to add account under
     */
    function addWhitelistedWithDID(address account, string memory did)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        _addWhitelistedWithDID(account, did);
    }

    /* @dev Removes an address as whitelisted.
     * Can only be called by Identity Administrators.
     * @param account address to remove as whitelisted
     */
    function removeWhitelisted(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        _removeWhitelisted(account);
    }

    /* @dev Renounces message sender from whitelisted
     */
    function renounceWhitelisted() public whenNotPaused {
        _removeWhitelisted(msg.sender);
    }

    /* @dev Returns true if given address has been added to whitelist
     * @param account the address to check
     * @return a bool indicating weather the address is present in whitelist
     */
    function isWhitelisted(address account) public view returns (bool) {
        uint256 daysSinceAuthentication = (now.sub(dateAuthenticated[account])) / 1 days;
        return
            (daysSinceAuthentication <= authenticationPeriod) && whitelist.has(account);
    }

    /* @dev Function that gives the date the given user was added
     * @param account The address to check
     * @return The date the address was added
     */
    function lastAuthenticated(address account) public view returns (uint256) {
        return dateAuthenticated[account];
    }

    // /**
    //  *
    //  * @dev Function to transfer whitelisted privilege to another address
    //  * relocates did of sender to give address
    //  * @param account The address to transfer to
    //  */
    // function transferAccount(address account) public whenNotPaused {
    //     ERC20 token = avatar.nativeToken();
    //     require(!isBlacklisted(account), "Cannot transfer to blacklisted");
    //     require(token.balanceOf(account) == 0, "Account is already in use");
    //     require(isWhitelisted(msg.sender), "Requester need to be whitelisted");

    //     require(
    //         keccak256(bytes(addrToDID[account])) == keccak256(bytes("")),
    //         "address already has DID"
    //     );

    //     string memory did = addrToDID[msg.sender];
    //     bytes32 pHash = keccak256(bytes(did));

    //     uint256 balance = token.balanceOf(msg.sender);
    //     token.transferFrom(msg.sender, account, balance);
    //     _removeWhitelisted(msg.sender);
    //     _addWhitelisted(account);
    //     addrToDID[account] = did;
    //     didHashToAddress[pHash] = account;
    // }

    /* @dev Adds an address to blacklist.
     * Can only be called by Identity Administrators.
     * @param account address to add as blacklisted
     */
    function addBlacklisted(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        blacklist.add(account);
        emit BlacklistAdded(account);
    }

    /* @dev Removes an address from blacklist
     * Can only be called by Identity Administrators.
     * @param account address to remove as blacklisted
     */
    function removeBlacklisted(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        blacklist.remove(account);
        emit BlacklistRemoved(account);
    }

    /* @dev Function to add a Contract to list of contracts
     * @param account The address to add
     */
    function addContract(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        require(isContract(account), "Given address is not a contract");
        contracts.add(account);
        _addWhitelisted(account);

        emit ContractAdded(account);
    }

    /* @dev Function to remove a Contract from list of contracts
     * @param account The address to add
     */
    function removeContract(address account)
        public
        onlyRegistered
        onlyIdentityAdmin
        whenNotPaused
    {
        contracts.remove(account);
        _removeWhitelisted(account);

        emit ContractRemoved(account);
    }

    /* @dev Function to check if given contract is on list of contracts.
     * @param address to check
     * @return a bool indicating if address is on list of contracts
     */
    function isDAOContract(address account) public view returns (bool) {
        return contracts.has(account);
    }

    /* @dev Internal function to add to whitelisted
     * @param account the address to add
     */
    function _addWhitelisted(address account) internal {
        whitelist.add(account);

        whitelistedCount += 1;
        dateAdded[account] = now;
        dateAuthenticated[account] = now;

        if (isContract(account)) {
            whitelistedContracts += 1;
        }

        emit WhitelistedAdded(account);
    }

    /* @dev Internal whitelisting with did function.
     * @param account the address to add
     * @param did the id to register account under
     */
    function _addWhitelistedWithDID(address account, string memory did) internal {
        bytes32 pHash = keccak256(bytes(did));
        require(didHashToAddress[pHash] == address(0), "DID already registered");

        addrToDID[account] = did;
        didHashToAddress[pHash] = account;

        _addWhitelisted(account);
    }

    /* @dev Internal function to remove from whitelisted
     * @param account the address to add
     */
    function _removeWhitelisted(address account) internal {
        whitelist.remove(account);

        whitelistedCount -= 1;
        delete dateAuthenticated[account];

        if (isContract(account)) {
            whitelistedContracts -= 1;
        }

        string memory did = addrToDID[account];
        bytes32 pHash = keccak256(bytes(did));

        delete dateAuthenticated[account];
        delete addrToDID[account];
        delete didHashToAddress[pHash];

        emit WhitelistedRemoved(account);
    }

    /* @dev Returns true if given address has been added to the blacklist
     * @param account the address to check
     * @return a bool indicating weather the address is present in the blacklist
     */
    function isBlacklisted(address account) public view returns (bool) {
        return blacklist.has(account);
    }

    /* @dev Function to see if given address is a contract
     * @return true if address is a contract
     */
    function isContract(address _addr) internal view returns (bool) {
        uint256 length;
        assembly {
            length := extcodesize(_addr)
        }
        return length > 0;
    }
}

/* @title The IdentityGuard contract
 * @dev Contract containing an identity and
 * modifiers to ensure proper access
 */
contract IdentityGuard is Ownable {
    Identity public identity;

    /* @dev Constructor. Checks if identity is a zero address
     * @param _identity The identity contract.
     */
    constructor(Identity _identity) public {
        require(_identity != Identity(0), "Supplied identity is null");
        identity = _identity;
    }

    /* @dev Modifier that requires the sender to be not blacklisted
     */
    modifier onlyNotBlacklisted() {
        require(!identity.isBlacklisted(msg.sender), "Caller is blacklisted");
        _;
    }

    /* @dev Modifier that requires the given address to be not blacklisted
     * @param _account The address to be checked
     */
    modifier requireNotBlacklisted(address _account) {
        require(!identity.isBlacklisted(_account), "Receiver is blacklisted");
        _;
    }

    /* @dev Modifier that requires the sender to be whitelisted
     */
    modifier onlyWhitelisted() {
        require(identity.isWhitelisted(msg.sender), "is not whitelisted");
        _;
    }

    /* @dev Modifier that requires the given address to be whitelisted
     * @param _account the given address
     */
    modifier requireWhitelisted(address _account) {
        require(identity.isWhitelisted(_account), "is not whitelisted");
        _;
    }

    /* @dev Modifier that requires the sender to be an approved DAO contract
     */
    modifier onlyDAOContract() {
        require(identity.isDAOContract(msg.sender), "is not whitelisted contract");
        _;
    }

    /* @dev Modifier that requires the given address to be whitelisted
     * @param _account the given address
     */
    modifier requireDAOContract(address _contract) {
        require(identity.isDAOContract(_contract), "is not whitelisted contract");
        _;
    }

    /* @dev Modifier that requires the sender to have been whitelisted
     * before or on the given date
     * @param date The time sender must have been added before
     */
    modifier onlyAddedBefore(uint256 date) {
        require(
            identity.lastAuthenticated(msg.sender) <= date,
            "Was not added within period"
        );
        _;
    }

    /* @dev Modifier that requires sender to be an identity admin
     */
    modifier onlyIdentityAdmin() {
        require(identity.isIdentityAdmin(msg.sender), "not IdentityAdmin");
        _;
    }

    /* @dev Allows owner to set a new identity contract if
     * the given identity contract has been registered as a scheme
     */
    function setIdentity(Identity _identity) public onlyOwner {
        require(_identity.isRegistered(), "Identity is not registered");
        identity = _identity;
    }
}

/**
 * @dev Contract for letting scheme add itself to identity
 * to allow transferring GoodDollar without paying fees
 * and transfer ownership to Avatar
 */
contract FeelessScheme is SchemeGuard, IdentityGuard {
    /* @dev Constructor
     * @param _identity The identity contract
     * @param _avatar The avatar of the DAO
     */
    constructor(Identity _identity, Avatar _avatar)
        public
        SchemeGuard(_avatar)
        IdentityGuard(_identity)
    {}

    /* @dev Internal function to add contract to identity.
     * Can only be called if scheme is registered.
     */
    function addRights() internal onlyRegistered {
        controller.genericCall(
            address(identity),
            abi.encodeWithSignature("addContract(address)", address(this)),
            avatar,
            0
        );
        transferOwnership(address(avatar));
    }

    /* @dev Internal function to remove contract from identity.
     * Can only be called if scheme is registered.
     */
    function removeRights() internal onlyRegistered {
        controller.genericCall(
            address(identity),
            abi.encodeWithSignature("removeContract(address)", address(this)),
            avatar,
            0
        );
    }
}

/// math.sol -- mixin for inline numerical wizardry
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.
contract DSMath {
    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x + y) >= x, "ds-math-add-overflow");
    }
    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x - y) <= x, "ds-math-sub-underflow");
    }
    function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require(y == 0 || (z = x * y) / y == x, "ds-math-mul-overflow");
    }

    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
        return x <= y ? x : y;
    }
    function max(uint256 x, uint256 y) internal pure returns (uint256 z) {
        return x >= y ? x : y;
    }
    function imin(int256 x, int256 y) internal pure returns (int256 z) {
        return x <= y ? x : y;
    }
    function imax(int256 x, int256 y) internal pure returns (int256 z) {
        return x >= y ? x : y;
    }

    uint256 constant WAD = 10**18;
    uint256 constant RAY = 10**27;

    function wmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, y), WAD / 2) / WAD;
    }
    function rmul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, y), RAY / 2) / RAY;
    }
    function wdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, WAD), y / 2) / y;
    }
    function rdiv(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = add(mul(x, RAY), y / 2) / y;
    }

    // This famous algorithm is called "exponentiation by squaring"
    // and calculates x^n with x as fixed-point and n as regular unsigned.
    //
    // It's O(log n), instead of O(n) for naive repeated multiplication.
    //
    // These facts are why it works:
    //
    //  If n is even, then x^n = (x^2)^(n/2).
    //  If n is odd,  then x^n = x * x^(n-1),
    //   and applying the equation for even x gives
    //    x^n = x * (x^2)^((n-1) / 2).
    //
    //  Also, EVM division is flooring and
    //    floor[(n-1) / 2] = floor[n / 2].
    //
    function rpow(uint256 x, uint256 n) internal pure returns (uint256 z) {
        z = n % 2 != 0 ? x : RAY;

        for (n /= 2; n != 0; n /= 2) {
            x = rmul(x, x);

            if (n % 2 != 0) {
                z = rmul(z, x);
            }
        }
    }
}

interface cERC20 {
    function mint(uint256 mintAmount) external returns (uint256);

    function redeemUnderlying(uint256 mintAmount) external returns (uint256);

    function exchangeRateCurrent() external returns (uint256);

    function exchangeRateStored() external view returns (uint256);

    function balanceOf(address addr) external view returns (uint256);

    function transfer(address to, uint256 amount) external returns (bool);
}

/**
 * @title Staking contract that donates earned interest to the DAO
 * allowing stakers to deposit DAI or withdraw their stake in DAI.
 * The contract buys cDAI and can transfer the daily interest to the DAO
 */
contract SimpleDAIStaking is DSMath, Pausable, FeelessScheme {
    using SafeMath for uint256;

    // Entity that holds a staker info
    struct Staker {
        // The staked DAI amount
        uint256 stakedDAI;
        // The latest block number which the
        // staker has staked tokens
        uint256 lastStake;
    }

    // The map which holds the stakers entities
    mapping(address => Staker) public stakers;

    // Emits when new DAI tokens have been staked
    event DAIStaked(
        // The staker address
        address indexed staker,
        // How many tokens have been staked
        uint256 daiValue
    );

    // Emits when DAI tokens are being withdrawn
    event DAIStakeWithdraw(
        // The staker that initiate the action
        address indexed staker,
        // The initial DAI value that was staked
        uint256 daiValue,
        // The current DAI value that was staked
        uint256 daiActual
    );

    // Emits when the interest is collected
    event InterestCollected(
        // Who is receives the interest
        address recipient,
        // How many cDAI tokens have been transferred
        uint256 cdaiValue,
        // The worth of the transferred tokens in DAI
        uint256 daiValue,
        // Lost amount. A result of different precisions
        uint256 daiPrecisionLoss
    );

    // DAI token address
    ERC20 public dai;

    // cDAI token address
    cERC20 public cDai;

    // The block interval defines the number of
    // blocks that shall be passed before the
    // next execution of `collectUBIInterest`
    uint256 public blockInterval;

    // The last block number which
    // `collectUBIInterest` has been executed in
    uint256 public lastUBICollection;

    // The total staked DAI amount in the contract
    uint256 public totalStaked = 0;

    // How much of the generated interest is donated,
    // meaning no GD is expected in compensation, 1 in mil precision.
    // 100% for phase0 POC
    uint32 public avgInterestDonatedRatio = 1e6;

    // The address of the fund manager contract
    address public fundManager;

    modifier onlyFundManager {
        require(msg.sender == fundManager, "Only FundManager can call this method");
        _;
    }

    /**
     * @dev Constructor
     * @param _dai The address of DAI
     * @param _cDai The address of cDAI
     * @param _fundManager The address of the fund manager contract
     * @param _blockInterval How many blocks should be passed before the next execution of `collectUBIInterest`
     * @param _avatar The avatar of the DAO
     * @param _identity The identity contract
     */
    constructor(
        address _dai,
        address _cDai,
        address _fundManager,
        uint256 _blockInterval,
        Avatar _avatar,
        Identity _identity
    ) public FeelessScheme(_identity, _avatar) {
        dai = ERC20(_dai);
        cDai = cERC20(_cDai);
        blockInterval = _blockInterval;
        lastUBICollection = block.number.div(blockInterval);
        fundManager = _fundManager;

        // Adds the avatar as a pauser of this contract
        addPauser(address(avatar));
    }

    /**
     * @dev Allows the DAO to change the fund manager contract address
     * @param _fundManager Address of the new contract
     */
    function setFundManager(address _fundManager) public onlyAvatar {
        fundManager = _fundManager;
    }

    /**
     * @dev Allows a staker to deposit DAI tokens. Notice that `approve` is
     * needed to be executed before the execution of this method.
     * Can be executed only when the contract is not paused.
     * @param _amount The amount of DAI to stake
     */
    function stakeDAI(uint256 _amount) public whenNotPaused {
        require(_amount > 0, "You need to stake a positive token amount");
        require(
            dai.transferFrom(msg.sender, address(this), _amount) == true,
            "transferFrom failed, make sure you approved DAI transfer"
        );

        // approve the transfer to cDAI
        dai.approve(address(cDai), _amount);

        // mint ctokens
        uint256 res = cDai.mint(_amount);

        // cDAI returns >0 if error happened while minting.
        // Makes sure that there are no errors. If an error
        // has occurred, DAI funds shall be returned.
        if (res > 0) {
            require(res == 0, "Minting cDai failed, funds returned");
        }

        // updated the staker entity
        Staker storage staker = stakers[msg.sender];
        staker.stakedDAI = staker.stakedDAI.add(_amount);
        staker.lastStake = block.number;

        // adds the staked amount to the total staked
        totalStaked = totalStaked.add(_amount);

        emit DAIStaked(msg.sender, _amount);
    }

    /**
     * @dev Withdraws the sender staked DAI.
     */
    function withdrawStake() public {
        Staker storage staker = stakers[msg.sender];
        require(staker.stakedDAI > 0, "No DAI staked");
        require(cDai.redeemUnderlying(staker.stakedDAI) == 0, "Failed to redeem cDai");
        uint256 daiWithdraw = staker.stakedDAI;

        // updates balance before transfer to prevent re-entry
        staker.stakedDAI = 0;

        totalStaked = totalStaked.sub(daiWithdraw);

        //redeeming in compound may result in a tiny fraction of precission error
        //so if we redeem 100 DAI we might get something like 99.9999999999
        uint256 daiActual = dai.balanceOf(address(this));
        if (daiActual < daiWithdraw) {
            daiWithdraw = daiActual;
        }
        require(dai.transfer(msg.sender, daiWithdraw), "withdraw transfer failed");
        emit DAIStakeWithdraw(msg.sender, daiWithdraw, daiActual);
    }

    /**
     * @dev Calculates the worth of the staked cDAI tokens in DAI.
     * @return (uint256) The worth in DAI
     */
    function currentDAIWorth() public view returns (uint256) {
        uint256 er = cDai.exchangeRateStored();

        //TODO: why 1e10? cDai is e8 so we should convert it to e28 like exchange rate
        uint256 daiBalance = rmul(cDai.balanceOf(address(this)).mul(1e10), er).div(10);
        return daiBalance;
    }

    /**
     * @dev Calculates the current interest that was gained.
     * @return (uint256, uint256, uint256) The interest in cDAI, the interest in DAI,
     * the amount which is not covered by precision of DAI
     */
    function currentUBIInterest()
        public
        view
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 er = cDai.exchangeRateStored();
        uint256 daiWorth = currentDAIWorth();
        if (daiWorth <= totalStaked) {
            return (0, 0, 0);
        }
        uint256 daiGains = daiWorth.sub(totalStaked);
        // mul by 1e10 to equalize precision otherwise since exchangerate
        // is very big, dividing by it would result in 0.
        uint256 cdaiGains = rdiv(daiGains.mul(1e10), er);
        // gets right most bits not covered by precision of cdai which is
        // only 8 decimals while RAY is 27
        uint256 precisionLossCDaiRay = cdaiGains.mod(1e19);
        // lower back to 8 decimals
        cdaiGains = cdaiGains.div(1e19);
        //div by 1e10 to get results in dai precision 1e18
        uint256 precisionLossDai = rmul(precisionLossCDaiRay, er).div(1e10);
        return (cdaiGains, daiGains, precisionLossDai);
    }

    /**
     * @dev Collects gained interest by fundmanager. Can be collected only once
     * in an interval which is defined above.
     * @param _recipient The recipient of cDAI gains
     * @return (uint256, uint256, uint256, uint32) The interest in cDAI, the interest in DAI,
     * the amount which is not covered by precision of DAI, how much of the generated interest is donated
     */
    function collectUBIInterest(address _recipient)
        public
        onlyFundManager
        returns (
            uint256,
            uint256,
            uint256,
            uint32
        )
    {
        // otherwise fund manager has to wait for the next interval
        require(_recipient != address(this), "Recipient cannot be the staking contract");

        require(canCollect(), "Need to wait for the next interval");

        (
            uint256 cdaiGains,
            uint256 daiGains,
            uint256 precisionLossDai
        ) = currentUBIInterest();
        lastUBICollection = block.number.div(blockInterval);
        if (cdaiGains > 0)
            require(cDai.transfer(_recipient, cdaiGains), "collect transfer failed");
        emit InterestCollected(_recipient, cdaiGains, daiGains, precisionLossDai);
        return (cdaiGains, daiGains, precisionLossDai, avgInterestDonatedRatio);
    }

    /**
     * @dev Checks if enough blocks have passed so it would be possible to
     * execute `collectUBIInterest` according to the length of `blockInterval`
     * @return (bool) True if enough blocks have passed
     */
    function canCollect() public view returns (bool) {
        return block.number.div(blockInterval) > lastUBICollection;
    }

    /**
     * @dev Start function. Adds this contract to identity as a feeless scheme.
     * Can only be called if scheme is registered
     */
    function start() public onlyRegistered {
        addRights();
    }

    /**
     * @dev making the contract inactive
     * NOTICE: this could theoretically result in future interest earned in cdai to remain locked
     * but we dont expect any other stakers but us in SimpleDAIStaking
     */
    function end() public onlyAvatar {
        pause();
        removeRights();
    }

    /**
     * @dev method to recover any stuck erc20 tokens (ie  compound COMP)
     * @param _token the ERC20 token to recover
     */
    function recover(ERC20 _token) public onlyAvatar {
        uint256 toWithdraw = _token.balanceOf(address(this));

        // recover left cDai(stakers token) only when all stakes have been withdrawn
        if (address(_token) == address(cDai)) {
            require(
                totalStaked == 0 && paused(),
                "can recover cDai only when stakes have been withdrawn"
            );
        }
        require(_token.transfer(address(avatar), toWithdraw), "recover transfer failed");
    }
}