Cryo Explorer Ethereum Mainnet

// File: @openzeppelin/contracts/math/SafeMath.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot 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-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: contracts/SafeMath96.sol

pragma solidity 0.6.12;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath96 {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint96 a, uint256 b) internal pure returns (uint96) {
        require(uint256(uint96(b)) == b, "SafeMath: addition overflow");
        uint96 c = a + uint96(b);
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint96 a, uint256 b) internal pure returns (uint96) {
        require(uint256(uint96(b)) == b, "SafeMath: subtraction overflow");
        return sub(a, uint96(b), "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
        require(b <= a, errorMessage);
        uint96 c = a - b;

        return c;
    }

}

// File: @openzeppelin/contracts/math/Math.sol

pragma solidity ^0.6.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: 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
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts/spec_interfaces/ICommittee.sol

pragma solidity 0.6.12;

/// @title Committee contract interface
interface ICommittee {
	event CommitteeChange(address indexed addr, uint256 weight, bool certification, bool inCommittee);
	event CommitteeSnapshot(address[] addrs, uint256[] weights, bool[] certification);

	// No external functions

	/*
     * External functions
     */

    /// Notifies a weight change of a member
    /// @dev Called only by: Elections contract
    /// @param addr is the committee member address
    /// @param weight is the updated weight of the committee member
	function memberWeightChange(address addr, uint256 weight) external /* onlyElectionsContract onlyWhenActive */;

    /// Notifies a change in the certification of a member
    /// @dev Called only by: Elections contract
    /// @param addr is the committee member address
    /// @param isCertified is the updated certification state of the member
	function memberCertificationChange(address addr, bool isCertified) external /* onlyElectionsContract onlyWhenActive */;

    /// Notifies a member removal for example due to voteOut or voteUnready
    /// @dev Called only by: Elections contract
    /// @param memberRemoved is the removed committee member address
    /// @return memberRemoved indicates whether the member was removed from the committee
    /// @return removedMemberWeight indicates the removed member weight
    /// @return removedMemberCertified indicates whether the member was in the certified committee
	function removeMember(address addr) external returns (bool memberRemoved, uint removedMemberWeight, bool removedMemberCertified)/* onlyElectionContract */;

    /// Notifies a new member applicable for committee (due to registration, unbanning, certification change)
    /// The new member will be added only if it is qualified to join the committee 
    /// @dev Called only by: Elections contract
    /// @param addr is the added committee member address
    /// @param weight is the added member weight
    /// @param isCertified is the added member certification state
    /// @return memberAdded bool indicates whether the member was added
	function addMember(address addr, uint256 weight, bool isCertified) external returns (bool memberAdded)  /* onlyElectionsContract */;

    /// Checks if addMember() would add a the member to the committee (qualified to join)
    /// @param addr is the candidate committee member address
    /// @param weight is the candidate committee member weight
    /// @return wouldAddMember bool indicates whether the member will be added
	function checkAddMember(address addr, uint256 weight) external view returns (bool wouldAddMember);

    /// Returns the committee members and their weights
    /// @return addrs is the committee members list
    /// @return weights is an array of uint, indicating committee members list weight
    /// @return certification is an array of bool, indicating the committee members certification status
	function getCommittee() external view returns (address[] memory addrs, uint256[] memory weights, bool[] memory certification);

    /// Returns the currently appointed committee data
    /// @return generalCommitteeSize is the number of members in the committee
    /// @return certifiedCommitteeSize is the number of certified members in the committee
    /// @return totalWeight is the total effective stake (weight) of the committee
	function getCommitteeStats() external view returns (uint generalCommitteeSize, uint certifiedCommitteeSize, uint totalWeight);

    /// Returns a committee member data
    /// @param addr is the committee member address
    /// @return inCommittee indicates whether the queried address is a member in the committee
    /// @return weight is the committee member weight
    /// @return isCertified indicates whether the committee member is certified
    /// @return totalCommitteeWeight is the total weight of the committee.
	function getMemberInfo(address addr) external view returns (bool inCommittee, uint weight, bool isCertified, uint totalCommitteeWeight);

    /// Emits a CommitteeSnapshot events with current committee info
    /// @dev a CommitteeSnapshot is useful on contract migration or to remove the need to track past events.
	function emitCommitteeSnapshot() external;

	/*
	 * Governance functions
	 */

	event MaxCommitteeSizeChanged(uint8 newValue, uint8 oldValue);

    /// Sets the maximum number of committee members
    /// @dev governance function called only by the functional manager
    /// @dev when reducing the number of members, the bottom ones are removed from the committee
    /// @param _maxCommitteeSize is the maximum number of committee members 
	function setMaxCommitteeSize(uint8 _maxCommitteeSize) external /* onlyFunctionalManager */;

    /// Returns the maximum number of committee members
    /// @return maxCommitteeSize is the maximum number of committee members 
	function getMaxCommitteeSize() external view returns (uint8);
	
    /// Imports the committee members from a previous committee contract during migration
    /// @dev initialization function called only by the initializationManager
    /// @dev does not update the reward contract to avoid incorrect notifications 
    /// @param previousCommitteeContract is the address of the previous committee contract
	function importMembers(ICommittee previousCommitteeContract) external /* onlyInitializationAdmin */;
}

// File: contracts/spec_interfaces/IProtocolWallet.sol

pragma solidity 0.6.12;


/// @title Protocol Wallet interface
interface IProtocolWallet {
    event FundsAddedToPool(uint256 added, uint256 total);

    /*
    * External functions
    */

    /// Returns the address of the underlying staked token
    /// @return balance is the wallet balance
    function getBalance() external view returns (uint256 balance);

    /// Transfers the given amount of orbs tokens form the sender to this contract and updates the pool
    /// @dev assumes the caller approved the amount prior to calling
    /// @param amount is the amount to add to the wallet
    function topUp(uint256 amount) external;

    /// Withdraws from pool to the client address, limited by the pool's MaxRate.
    /// @dev may only be called by the wallet client
    /// @dev no more than MaxRate x time period since the last withdraw may be withdrawn
    /// @dev allocation that wasn't withdrawn can not be withdrawn in the next call
    /// @param amount is the amount to withdraw
    function withdraw(uint256 amount) external; /* onlyClient */


    /*
    * Governance functions
    */

    event ClientSet(address client);
    event MaxAnnualRateSet(uint256 maxAnnualRate);
    event EmergencyWithdrawal(address addr, address token);
    event OutstandingTokensReset(uint256 startTime);

    /// Sets a new annual withdraw rate for the pool
    /// @dev governance function called only by the migration owner
    /// @dev the rate for a duration is duration x annualRate / 1 year 
    /// @param _annualRate is the maximum annual rate that can be withdrawn
    function setMaxAnnualRate(uint256 _annualRate) external; /* onlyMigrationOwner */

    /// Returns the annual withdraw rate of the pool
    /// @return annualRate is the maximum annual rate that can be withdrawn
    function getMaxAnnualRate() external view returns (uint256);

    /// Resets the outstanding tokens to new start time
    /// @dev governance function called only by the migration owner
    /// @dev the next duration will be calculated starting from the given time
    /// @param startTime is the time to set as the last withdrawal time
    function resetOutstandingTokens(uint256 startTime) external; /* onlyMigrationOwner */

    /// Emergency withdraw the wallet funds
    /// @dev governance function called only by the migration owner
    /// @dev used in emergencies, when a migration to a new wallet is needed
    /// @param erc20 is the erc20 address of the token to withdraw
    function emergencyWithdraw(address erc20) external; /* onlyMigrationOwner */

    /// Sets the address of the client that can withdraw funds
    /// @dev governance function called only by the functional owner
    /// @param _client is the address of the new client
    function setClient(address _client) external; /* onlyFunctionalOwner */

}

// File: contracts/spec_interfaces/IStakingRewards.sol

pragma solidity 0.6.12;

/// @title Staking rewards contract interface
interface IStakingRewards {

    event DelegatorStakingRewardsAssigned(address indexed delegator, uint256 amount, uint256 totalAwarded, address guardian, uint256 delegatorRewardsPerToken, uint256 delegatorRewardsPerTokenDelta);
    event GuardianStakingRewardsAssigned(address indexed guardian, uint256 amount, uint256 totalAwarded, uint256 delegatorRewardsPerToken, uint256 delegatorRewardsPerTokenDelta, uint256 stakingRewardsPerWeight, uint256 stakingRewardsPerWeightDelta);
    event StakingRewardsClaimed(address indexed addr, uint256 claimedDelegatorRewards, uint256 claimedGuardianRewards, uint256 totalClaimedDelegatorRewards, uint256 totalClaimedGuardianRewards);
    event StakingRewardsAllocated(uint256 allocatedRewards, uint256 stakingRewardsPerWeight);
    event GuardianDelegatorsStakingRewardsPercentMilleUpdated(address indexed guardian, uint256 delegatorsStakingRewardsPercentMille);

    /*
     * External functions
     */

    /// Returns the current reward balance of the given address.
    /// @dev calculates the up to date balances (differ from the state)
    /// @param addr is the address to query
    /// @return delegatorStakingRewardsBalance the rewards awarded to the guardian role
    /// @return guardianStakingRewardsBalance the rewards awarded to the guardian role
    function getStakingRewardsBalance(address addr) external view returns (uint256 delegatorStakingRewardsBalance, uint256 guardianStakingRewardsBalance);

    /// Claims the staking rewards balance of an addr, staking the rewards
    /// @dev Claimed rewards are staked in the staking contract using the distributeRewards interface
    /// @dev includes the rewards for both the delegator and guardian roles
    /// @dev calculates the up to date rewards prior to distribute them to the staking contract
    /// @param addr is the address to claim rewards for
    function claimStakingRewards(address addr) external;

    /// Returns the current global staking rewards state
    /// @dev calculated to the latest block, may differ from the state read
    /// @return stakingRewardsPerWeight is the potential reward per 1E18 (TOKEN_BASE) committee weight assigned to a guardian was in the committee from day zero
    /// @return unclaimedStakingRewards is the of tokens that were assigned to participants and not claimed yet
    function getStakingRewardsState() external view returns (
        uint96 stakingRewardsPerWeight,
        uint96 unclaimedStakingRewards
    );

    /// Returns the current guardian staking rewards state
    /// @dev calculated to the latest block, may differ from the state read
    /// @dev notice that the guardian rewards are the rewards for the guardian role as guardian and do not include delegation rewards
    /// @dev use getDelegatorStakingRewardsData to get the guardian's rewards as delegator
    /// @param guardian is the guardian to query
    /// @return balance is the staking rewards balance for the guardian role
    /// @return claimed is the staking rewards for the guardian role that were claimed
    /// @return delegatorRewardsPerToken is the potential reward per token (1E18 units) assigned to a guardian's delegator that delegated from day zero
    /// @return delegatorRewardsPerTokenDelta is the increment in delegatorRewardsPerToken since the last guardian update
    /// @return lastStakingRewardsPerWeight is the up to date stakingRewardsPerWeight used for the guardian state calculation
    /// @return stakingRewardsPerWeightDelta is the increment in stakingRewardsPerWeight since the last guardian update
    function getGuardianStakingRewardsData(address guardian) external view returns (
        uint256 balance,
        uint256 claimed,
        uint256 delegatorRewardsPerToken,
        uint256 delegatorRewardsPerTokenDelta,
        uint256 lastStakingRewardsPerWeight,
        uint256 stakingRewardsPerWeightDelta
    );

    /// Returns the current delegator staking rewards state
    /// @dev calculated to the latest block, may differ from the state read
    /// @param delegator is the delegator to query
    /// @return balance is the staking rewards balance for the delegator role
    /// @return claimed is the staking rewards for the delegator role that were claimed
    /// @return guardian is the guardian the delegator delegated to receiving a portion of the guardian staking rewards
    /// @return lastDelegatorRewardsPerToken is the up to date delegatorRewardsPerToken used for the delegator state calculation
    /// @return delegatorRewardsPerTokenDelta is the increment in delegatorRewardsPerToken since the last delegator update
    function getDelegatorStakingRewardsData(address delegator) external view returns (
        uint256 balance,
        uint256 claimed,
        address guardian,
        uint256 lastDelegatorRewardsPerToken,
        uint256 delegatorRewardsPerTokenDelta
    );

    /// Returns an estimation for the delegator and guardian staking rewards for a given duration
    /// @dev the returned value is an estimation, assuming no change in the PoS state
    /// @dev the period calculated for start from the current block time until the current time + duration.
    /// @param addr is the address to estimate rewards for
    /// @param duration is the duration to calculate for in seconds
    /// @return estimatedDelegatorStakingRewards is the estimated reward for the delegator role
    /// @return estimatedGuardianStakingRewards is the estimated reward for the guardian role
    function estimateFutureRewards(address addr, uint256 duration) external view returns (
        uint256 estimatedDelegatorStakingRewards,
        uint256 estimatedGuardianStakingRewards
    );

    /// Sets the guardian's delegators staking reward portion
    /// @dev by default uses the defaultDelegatorsStakingRewardsPercentMille
    /// @param delegatorRewardsPercentMille is the delegators portion in percent-mille (0 - maxDelegatorsStakingRewardsPercentMille)
    function setGuardianDelegatorsStakingRewardsPercentMille(uint32 delegatorRewardsPercentMille) external;

    /// Returns a guardian's delegators staking reward portion
    /// @dev If not explicitly set, returns the defaultDelegatorsStakingRewardsPercentMille
    /// @return delegatorRewardsRatioPercentMille is the delegators portion in percent-mille
    function getGuardianDelegatorsStakingRewardsPercentMille(address guardian) external view returns (uint256 delegatorRewardsRatioPercentMille);

    /// Returns the amount of ORBS tokens in the staking rewards wallet allocated to staking rewards
    /// @dev The staking wallet balance must always larger than the allocated value
    /// @return allocated is the amount of tokens allocated in the staking rewards wallet
    function getStakingRewardsWalletAllocatedTokens() external view returns (uint256 allocated);

    /// Returns the current annual staking reward rate
    /// @dev calculated based on the current total committee weight
    /// @return annualRate is the current staking reward rate in percent-mille
    function getCurrentStakingRewardsRatePercentMille() external view returns (uint256 annualRate);

    /// Notifies an expected change in the committee membership of the guardian
    /// @dev Called only by: the Committee contract
    /// @dev called upon expected change in the committee membership of the guardian
    /// @dev triggers update of the global rewards state and the guardian rewards state
    /// @dev updates the rewards state based on the committee state prior to the change
    /// @param guardian is the guardian who's committee membership is updated
    /// @param weight is the weight of the guardian prior to the change
    /// @param totalCommitteeWeight is the total committee weight prior to the change
    /// @param inCommittee indicates whether the guardian was in the committee prior to the change
    /// @param inCommitteeAfter indicates whether the guardian is in the committee after the change
    function committeeMembershipWillChange(address guardian, uint256 weight, uint256 totalCommitteeWeight, bool inCommittee, bool inCommitteeAfter) external /* onlyCommitteeContract */;

    /// Notifies an expected change in a delegator and his guardian delegation state
    /// @dev Called only by: the Delegation contract
    /// @dev called upon expected change in a delegator's delegation state
    /// @dev triggers update of the global rewards state, the guardian rewards state and the delegator rewards state
    /// @dev on delegation change, updates also the new guardian and the delegator's lastDelegatorRewardsPerToken accordingly
    /// @param guardian is the delegator's guardian prior to the change
    /// @param guardianDelegatedStake is the delegated stake of the delegator's guardian prior to the change
    /// @param delegator is the delegator about to change delegation state
    /// @param delegatorStake is the stake of the delegator
    /// @param nextGuardian is the delegator's guardian after to the change
    /// @param nextGuardianDelegatedStake is the delegated stake of the delegator's guardian after to the change
    function delegationWillChange(address guardian, uint256 guardianDelegatedStake, address delegator, uint256 delegatorStake, address nextGuardian, uint256 nextGuardianDelegatedStake) external /* onlyDelegationsContract */;

    /*
     * Governance functions
     */

    event AnnualStakingRewardsRateChanged(uint256 annualRateInPercentMille, uint256 annualCap);
    event DefaultDelegatorsStakingRewardsChanged(uint32 defaultDelegatorsStakingRewardsPercentMille);
    event MaxDelegatorsStakingRewardsChanged(uint32 maxDelegatorsStakingRewardsPercentMille);
    event RewardDistributionActivated(uint256 startTime);
    event RewardDistributionDeactivated();
    event StakingRewardsBalanceMigrated(address indexed addr, uint256 guardianStakingRewards, uint256 delegatorStakingRewards, address toRewardsContract);
    event StakingRewardsBalanceMigrationAccepted(address from, address indexed addr, uint256 guardianStakingRewards, uint256 delegatorStakingRewards);
    event EmergencyWithdrawal(address addr, address token);

    /// Activates staking rewards allocation
    /// @dev governance function called only by the initialization admin
    /// @dev On migrations, startTime should be set to the previous contract deactivation time
    /// @param startTime sets the last assignment time
    function activateRewardDistribution(uint startTime) external /* onlyInitializationAdmin */;

    /// Deactivates fees and bootstrap allocation
    /// @dev governance function called only by the migration manager
    /// @dev guardians updates remain active based on the current perMember value
    function deactivateRewardDistribution() external /* onlyMigrationManager */;
    
    /// Sets the default delegators staking reward portion
    /// @dev governance function called only by the functional manager
    /// @param defaultDelegatorsStakingRewardsPercentMille is the default delegators portion in percent-mille(0 - maxDelegatorsStakingRewardsPercentMille)
    function setDefaultDelegatorsStakingRewardsPercentMille(uint32 defaultDelegatorsStakingRewardsPercentMille) external /* onlyFunctionalManager */;

    /// Returns the default delegators staking reward portion
    /// @return defaultDelegatorsStakingRewardsPercentMille is the default delegators portion in percent-mille
    function getDefaultDelegatorsStakingRewardsPercentMille() external view returns (uint32);

    /// Sets the maximum delegators staking reward portion
    /// @dev governance function called only by the functional manager
    /// @param maxDelegatorsStakingRewardsPercentMille is the maximum delegators portion in percent-mille(0 - 100,000)
    function setMaxDelegatorsStakingRewardsPercentMille(uint32 maxDelegatorsStakingRewardsPercentMille) external /* onlyFunctionalManager */;

    /// Returns the default delegators staking reward portion
    /// @return maxDelegatorsStakingRewardsPercentMille is the maximum delegators portion in percent-mille
    function getMaxDelegatorsStakingRewardsPercentMille() external view returns (uint32);

    /// Sets the annual rate and cap for the staking reward
    /// @dev governance function called only by the functional manager
    /// @param annualRateInPercentMille is the annual rate in percent-mille
    /// @param annualCap is the annual staking rewards cap
    function setAnnualStakingRewardsRate(uint32 annualRateInPercentMille, uint96 annualCap) external /* onlyFunctionalManager */;

    /// Returns the annual staking reward rate
    /// @return annualStakingRewardsRatePercentMille is the annual rate in percent-mille
    function getAnnualStakingRewardsRatePercentMille() external view returns (uint32);

    /// Returns the annual staking rewards cap
    /// @return annualStakingRewardsCap is the annual rate in percent-mille
    function getAnnualStakingRewardsCap() external view returns (uint256);

    /// Checks if rewards allocation is active
    /// @return rewardAllocationActive is a bool that indicates that rewards allocation is active
    function isRewardAllocationActive() external view returns (bool);

    /// Returns the contract's settings
    /// @return annualStakingRewardsCap is the annual rate in percent-mille
    /// @return annualStakingRewardsRatePercentMille is the annual rate in percent-mille
    /// @return defaultDelegatorsStakingRewardsPercentMille is the default delegators portion in percent-mille
    /// @return maxDelegatorsStakingRewardsPercentMille is the maximum delegators portion in percent-mille
    /// @return rewardAllocationActive is a bool that indicates that rewards allocation is active
    function getSettings() external view returns (
        uint annualStakingRewardsCap,
        uint32 annualStakingRewardsRatePercentMille,
        uint32 defaultDelegatorsStakingRewardsPercentMille,
        uint32 maxDelegatorsStakingRewardsPercentMille,
        bool rewardAllocationActive
    );

    /// Migrates the staking rewards balance of the given addresses to a new staking rewards contract
    /// @dev The new rewards contract is determined according to the contracts registry
    /// @dev No impact of the calling contract if the currently configured contract in the registry
    /// @dev may be called also while the contract is locked
    /// @param addrs is the list of addresses to migrate
    function migrateRewardsBalance(address[] calldata addrs) external;

    /// Accepts addresses balance migration from a previous rewards contract
    /// @dev the function may be called by any caller that approves the amounts provided for transfer
    /// @param addrs is the list migrated addresses
    /// @param migratedGuardianStakingRewards is the list of received guardian rewards balance for each address
    /// @param migratedDelegatorStakingRewards is the list of received delegator rewards balance for each address
    /// @param totalAmount is the total amount of staking rewards migrated for all addresses in the list. Must match the sum of migratedGuardianStakingRewards and migratedDelegatorStakingRewards lists.
    function acceptRewardsBalanceMigration(address[] calldata addrs, uint256[] calldata migratedGuardianStakingRewards, uint256[] calldata migratedDelegatorStakingRewards, uint256 totalAmount) external;

    /// Performs emergency withdrawal of the contract balance
    /// @dev called with a token to withdraw, should be called twice with the fees and bootstrap tokens
    /// @dev governance function called only by the migration manager
    /// @param erc20 is the ERC20 token to withdraw
    function emergencyWithdraw(address erc20) external /* onlyMigrationManager */;
}

// File: contracts/spec_interfaces/IDelegations.sol

pragma solidity 0.6.12;

/// @title Delegations contract interface
interface IDelegations /* is IStakeChangeNotifier */ {

    // Delegation state change events
	event DelegatedStakeChanged(address indexed addr, uint256 selfDelegatedStake, uint256 delegatedStake, address indexed delegator, uint256 delegatorContributedStake);

    // Function calls
	event Delegated(address indexed from, address indexed to);

	/*
     * External functions
     */

    /// Delegate your stake
    /// @dev updates the election contract on the changes in the delegated stake
    /// @dev updates the rewards contract on the upcoming change in the delegator's delegation state
    /// @param to is the address to delegate to
	function delegate(address to) external /* onlyWhenActive */;

    /// Refresh the address stake for delegation power based on the staking contract
    /// @dev Disabled stake change update notifications from the staking contract may create mismatches
    /// @dev refreshStake re-syncs the stake data with the staking contract
    /// @param addr is the address to refresh its stake
	function refreshStake(address addr) external /* onlyWhenActive */;

    /// Refresh the addresses stake for delegation power based on the staking contract
    /// @dev Batched version of refreshStake
    /// @dev Disabled stake change update notifications from the staking contract may create mismatches
    /// @dev refreshStakeBatch re-syncs the stake data with the staking contract
    /// @param addrs is the list of addresses to refresh their stake
	function refreshStakeBatch(address[] calldata addrs) external /* onlyWhenActive */;

    /// Returns the delegate address of the given address
    /// @param addr is the address to query
    /// @return delegation is the address the addr delegated to
	function getDelegation(address addr) external view returns (address);

    /// Returns a delegator info
    /// @param addr is the address to query
    /// @return delegation is the address the addr delegated to
    /// @return delegatorStake is the stake of the delegator as reflected in the delegation contract
	function getDelegationInfo(address addr) external view returns (address delegation, uint256 delegatorStake);
	
    /// Returns the delegated stake of an addr 
    /// @dev an address that is not self delegating has a 0 delegated stake
    /// @param addr is the address to query
    /// @return delegatedStake is the address delegated stake
	function getDelegatedStake(address addr) external view returns (uint256);

    /// Returns the total delegated stake
    /// @dev delegatedStake - the total stake delegated to an address that is self delegating
    /// @dev the delegated stake of a non self-delegated address is 0
    /// @return totalDelegatedStake is the total delegatedStake of all the addresses
	function getTotalDelegatedStake() external view returns (uint256) ;

	/*
	 * Governance functions
	 */

	event DelegationsImported(address[] from, address indexed to);

	event DelegationInitialized(address indexed from, address indexed to);

    /// Imports delegations during initial migration
    /// @dev initialization function called only by the initializationManager
    /// @dev Does not update the Rewards or Election contracts
    /// @dev assumes deactivated Rewards
    /// @param from is a list of delegator addresses
    /// @param to is the address the delegators delegate to
	function importDelegations(address[] calldata from, address to) external /* onlyMigrationManager onlyDuringDelegationImport */;

    /// Initializes the delegation of an address during initial migration 
    /// @dev initialization function called only by the initializationManager
    /// @dev behaves identically to a delegate transaction sent by the delegator
    /// @param from is the delegator addresses
    /// @param to is the delegator delegates to
	function initDelegation(address from, address to) external /* onlyInitializationAdmin */;
}

// File: contracts/IMigratableStakingContract.sol

pragma solidity 0.6.12;


/// @title An interface for staking contracts which support stake migration.
interface IMigratableStakingContract {
    /// @dev Returns the address of the underlying staked token.
    /// @return IERC20 The address of the token.
    function getToken() external view returns (IERC20);

    /// @dev Stakes ORBS tokens on behalf of msg.sender. This method assumes that the user has already approved at least
    /// the required amount using ERC20 approve.
    /// @param _stakeOwner address The specified stake owner.
    /// @param _amount uint256 The number of tokens to stake.
    function acceptMigration(address _stakeOwner, uint256 _amount) external;

    event AcceptedMigration(address indexed stakeOwner, uint256 amount, uint256 totalStakedAmount);
}

// File: contracts/IStakingContract.sol

pragma solidity 0.6.12;


/// @title An interface for staking contracts.
interface IStakingContract {
    /// @dev Stakes ORBS tokens on behalf of msg.sender. This method assumes that the user has already approved at least
    /// the required amount using ERC20 approve.
    /// @param _amount uint256 The amount of tokens to stake.
    function stake(uint256 _amount) external;

    /// @dev Unstakes ORBS tokens from msg.sender. If successful, this will start the cooldown period, after which
    /// msg.sender would be able to withdraw all of his tokens.
    /// @param _amount uint256 The amount of tokens to unstake.
    function unstake(uint256 _amount) external;

    /// @dev Requests to withdraw all of staked ORBS tokens back to msg.sender. Stake owners can withdraw their ORBS
    /// tokens only after previously unstaking them and after the cooldown period has passed (unless the contract was
    /// requested to release all stakes).
    function withdraw() external;

    /// @dev Restakes unstaked ORBS tokens (in or after cooldown) for msg.sender.
    function restake() external;

    /// @dev Distributes staking rewards to a list of addresses by directly adding rewards to their stakes. This method
    /// assumes that the user has already approved at least the required amount using ERC20 approve. Since this is a
    /// convenience method, we aren't concerned about reaching block gas limit by using large lists. We assume that
    /// callers will be able to properly batch/paginate their requests.
    /// @param _totalAmount uint256 The total amount of rewards to distribute.
    /// @param _stakeOwners address[] The addresses of the stake owners.
    /// @param _amounts uint256[] The amounts of the rewards.
    function distributeRewards(uint256 _totalAmount, address[] calldata _stakeOwners, uint256[] calldata _amounts) external;

    /// @dev Returns the stake of the specified stake owner (excluding unstaked tokens).
    /// @param _stakeOwner address The address to check.
    /// @return uint256 The total stake.
    function getStakeBalanceOf(address _stakeOwner) external view returns (uint256);

    /// @dev Returns the total amount staked tokens (excluding unstaked tokens).
    /// @return uint256 The total staked tokens of all stake owners.
    function getTotalStakedTokens() external view returns (uint256);

    /// @dev Returns the time that the cooldown period ends (or ended) and the amount of tokens to be released.
    /// @param _stakeOwner address The address to check.
    /// @return cooldownAmount uint256 The total tokens in cooldown.
    /// @return cooldownEndTime uint256 The time when the cooldown period ends (in seconds).
    function getUnstakeStatus(address _stakeOwner) external view returns (uint256 cooldownAmount,
        uint256 cooldownEndTime);

    /// @dev Migrates the stake of msg.sender from this staking contract to a new approved staking contract.
    /// @param _newStakingContract IMigratableStakingContract The new staking contract which supports stake migration.
    /// @param _amount uint256 The amount of tokens to migrate.
    function migrateStakedTokens(IMigratableStakingContract _newStakingContract, uint256 _amount) external;

    event Staked(address indexed stakeOwner, uint256 amount, uint256 totalStakedAmount);
    event Unstaked(address indexed stakeOwner, uint256 amount, uint256 totalStakedAmount);
    event Withdrew(address indexed stakeOwner, uint256 amount, uint256 totalStakedAmount);
    event Restaked(address indexed stakeOwner, uint256 amount, uint256 totalStakedAmount);
    event MigratedStake(address indexed stakeOwner, uint256 amount, uint256 totalStakedAmount);
}

// File: contracts/spec_interfaces/IManagedContract.sol

pragma solidity 0.6.12;

/// @title managed contract interface, used by the contracts registry to notify the contract on updates
interface IManagedContract /* is ILockable, IContractRegistryAccessor, Initializable */ {

    /// Refreshes the address of the other contracts the contract interacts with
    /// @dev called by the registry contract upon an update of a contract in the registry
    function refreshContracts() external;

}

// File: contracts/spec_interfaces/IContractRegistry.sol

pragma solidity 0.6.12;

/// @title Contract registry contract interface
/// @dev The contract registry holds Orbs PoS contracts and managers lists
/// @dev The contract registry updates the managed contracts on changes in the contract list
/// @dev Governance functions restricted to managers access the registry to retrieve the manager address 
/// @dev The contract registry represents the source of truth for Orbs Ethereum contracts 
/// @dev By tracking the registry events or query before interaction, one can access the up to date contracts 
interface IContractRegistry {

	event ContractAddressUpdated(string contractName, address addr, bool managedContract);
	event ManagerChanged(string role, address newManager);
	event ContractRegistryUpdated(address newContractRegistry);

	/*
	* External functions
	*/

    /// Updates the contracts address and emits a corresponding event
    /// @dev governance function called only by the migrationManager or registryAdmin
    /// @param contractName is the contract name, used to identify it
    /// @param addr is the contract updated address
    /// @param managedContract indicates whether the contract is managed by the registry and notified on changes
	function setContract(string calldata contractName, address addr, bool managedContract) external /* onlyAdminOrMigrationManager */;

    /// Returns the current address of the given contracts
    /// @param contractName is the contract name, used to identify it
    /// @return addr is the contract updated address
	function getContract(string calldata contractName) external view returns (address);

    /// Returns the list of contract addresses managed by the registry
    /// @dev Managed contracts are updated on changes in the registry contracts addresses 
    /// @return addrs is the list of managed contracts
	function getManagedContracts() external view returns (address[] memory);

    /// Locks all the managed contracts 
    /// @dev governance function called only by the migrationManager or registryAdmin
    /// @dev When set all onlyWhenActive functions will revert
	function lockContracts() external /* onlyAdminOrMigrationManager */;

    /// Unlocks all the managed contracts 
    /// @dev governance function called only by the migrationManager or registryAdmin
	function unlockContracts() external /* onlyAdminOrMigrationManager */;
	
    /// Updates a manager address and emits a corresponding event
    /// @dev governance function called only by the registryAdmin
    /// @dev the managers list is a flexible list of role to the manager's address
    /// @param role is the managers' role name, for example "functionalManager"
    /// @param manager is the manager updated address
	function setManager(string calldata role, address manager) external /* onlyAdmin */;

    /// Returns the current address of the given manager
    /// @param role is the manager name, used to identify it
    /// @return addr is the manager updated address
	function getManager(string calldata role) external view returns (address);

    /// Sets a new contract registry to migrate to
    /// @dev governance function called only by the registryAdmin
    /// @dev updates the registry address record in all the managed contracts
    /// @dev by tracking the emitted ContractRegistryUpdated, tools can track the up to date contracts
    /// @param newRegistry is the new registry contract 
	function setNewContractRegistry(IContractRegistry newRegistry) external /* onlyAdmin */;

    /// Returns the previous contract registry address 
    /// @dev used when the setting the contract as a new registry to assure a valid registry
    /// @return previousContractRegistry is the previous contract registry
	function getPreviousContractRegistry() external view returns (address);
}

// File: contracts/spec_interfaces/IContractRegistryAccessor.sol

pragma solidity 0.6.12;


interface IContractRegistryAccessor {

    /// Sets the contract registry address
    /// @dev governance function called only by an admin
    /// @param newRegistry is the new registry contract 
    function setContractRegistry(IContractRegistry newRegistry) external /* onlyAdmin */;

    /// Returns the contract registry address
    /// @return contractRegistry is the contract registry address
    function getContractRegistry() external view returns (IContractRegistry contractRegistry);

    function setRegistryAdmin(address _registryAdmin) external /* onlyInitializationAdmin */;

}

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg....

// [truncated — 116611 bytes total]