// File: contracts/FlyzStakingDistributor.sol



// SPDX-License-Identifier: AGPL-3.0-or-later

pragma solidity 0.7.5;

import './interfaces/IFlyzTreasury.sol';

import './types/ERC20.sol';
import './types/Ownable.sol';

import './libraries/SafeERC20.sol';

contract FlyzStakingDistributor is Ownable {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    /* ====== VARIABLES ====== */

    address public immutable FLYZ;
    address public immutable treasury;

    uint256 public immutable epochLength; // seconds
    uint256 public nextEpochTime; // unix epoch time in seconds

    mapping(uint256 => Adjust) public adjustments;

    /* ====== STRUCTS ====== */

    struct Info {
        uint256 rate; // in ten-thousandths ( 5000 = 0.5% )
        address recipient;
    }
    Info[] public info;

    struct Adjust {
        bool add;
        uint256 rate;
        uint256 target;
    }

    /* ====== CONSTRUCTOR ====== */

    constructor(
        address _treasury,
        address _flyz,
        uint256 _epochLength,
        uint256 _nextEpochTime
    ) {
        require(_treasury != address(0));
        treasury = _treasury;
        require(_flyz != address(0));
        FLYZ = _flyz;
        epochLength = _epochLength;
        nextEpochTime = _nextEpochTime;
    }

    /* ====== PUBLIC FUNCTIONS ====== */

    /**
        @notice send epoch reward to staking contract
     */
    function distribute() external returns (bool) {
        if (nextEpochTime <= block.timestamp) {
            nextEpochTime = nextEpochTime.add(epochLength); // set next epoch time

            // distribute rewards to each recipient
            for (uint256 i = 0; i < info.length; i++) {
                if (info[i].rate > 0) {
                    IFlyzTreasury(treasury).mintRewards( // mint and send from treasury
                        info[i].recipient,
                        nextRewardAt(info[i].rate)
                    );
                    adjust(i); // check for adjustment
                }
            }
            return true;
        } else {
            return false;
        }
    }

    /* ====== INTERNAL FUNCTIONS ====== */

    /**
        @notice increment reward rate for collector
     */
    function adjust(uint256 _index) internal {
        Adjust memory adjustment = adjustments[_index];
        if (adjustment.rate != 0) {
            if (adjustment.add) {
                // if rate should increase
                info[_index].rate = info[_index].rate.add(adjustment.rate); // raise rate
                if (info[_index].rate >= adjustment.target) {
                    // if target met
                    adjustments[_index].rate = 0; // turn off adjustment
                }
            } else {
                // if rate should decrease
                info[_index].rate = info[_index].rate.sub(adjustment.rate); // lower rate
                if (info[_index].rate <= adjustment.target) {
                    // if target met
                    adjustments[_index].rate = 0; // turn off adjustment
                }
            }
        }
    }

    /* ====== VIEW FUNCTIONS ====== */

    /**
        @notice view function for next reward at given rate
        @param _rate uint
        @return uint
     */
    function nextRewardAt(uint256 _rate) public view returns (uint256) {
        return IERC20(FLYZ).totalSupply().mul(_rate).div(1000000);
    }

    /**
        @notice view function for next reward for specified address
        @param _recipient address
        @return uint
     */
    function nextRewardFor(address _recipient) public view returns (uint256) {
        uint256 reward;
        for (uint256 i = 0; i < info.length; i++) {
            if (info[i].recipient == _recipient) {
                reward = nextRewardAt(info[i].rate);
            }
        }
        return reward;
    }

    /* ====== POLICY FUNCTIONS ====== */

    /**
        @notice adds recipient for distributions
        @param _recipient address
        @param _rewardRate uint
     */
    function addRecipient(address _recipient, uint256 _rewardRate)
        external
        onlyOwner
    {
        require(_recipient != address(0));
        info.push(Info({recipient: _recipient, rate: _rewardRate}));
    }

    /**
        @notice removes recipient for distributions
        @param _index uint
        @param _recipient address
     */
    function removeRecipient(uint256 _index, address _recipient)
        external
        onlyOwner
    {
        require(_recipient == info[_index].recipient);
        info[_index].recipient = address(0);
        info[_index].rate = 0;
    }

    /**
        @notice set adjustment info for a collector's reward rate
        @param _index uint
        @param _add bool
        @param _rate uint
        @param _target uint
     */
    function setAdjustment(
        uint256 _index,
        bool _add,
        uint256 _rate,
        uint256 _target
    ) external onlyOwner {
        adjustments[_index] = Adjust({add: _add, rate: _rate, target: _target});
    }
}

// File: contracts/interfaces/IFlyzTreasury.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

interface IFlyzTreasury {
    function excessReserves() external view returns (uint256);

    function deposit(
        uint256 _amount,
        address _token,
        uint256 _profit
    ) external returns (uint256 sent_);

    function valueOfToken(address _token, uint256 _amount)
        external
        view
        returns (uint256 value_);

    function mintRewards(address _recipient, uint256 _amount) external;

    function manage(address _token, uint256 _amount) external;

    function withdraw(uint256 _amount, address _token) external;
}

// File: contracts/types/ERC20.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

import '../interfaces/IERC20.sol';
import '../libraries/SafeMath.sol';
import '../libraries/Counters.sol';
import '../libraries/Address.sol';

abstract contract ERC20 is IERC20 {
    using SafeMath for uint256;

    // TODO comment actual hash value.
    bytes32 private constant ERC20TOKEN_ERC1820_INTERFACE_ID =
        keccak256('ERC20Token');

    mapping(address => uint256) internal _balances;

    mapping(address => mapping(address => uint256)) internal _allowances;

    uint256 internal _totalSupply;

    string internal _name;

    string internal _symbol;

    uint8 internal _decimals;

    constructor(
        string memory name_,
        string memory symbol_,
        uint8 decimals_
    ) {
        _name = name_;
        _symbol = symbol_;
        _decimals = decimals_;
    }

    function name() public view override returns (string memory) {
        return _name;
    }

    function symbol() public view override returns (string memory) {
        return _symbol;
    }

    function decimals() public view override returns (uint8) {
        return _decimals;
    }

    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function allowance(address owner, address spender)
        public
        view
        virtual
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            msg.sender,
            _allowances[sender][msg.sender].sub(
                amount,
                'ERC20: transfer amount exceeds allowance'
            )
        );
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
    {
        _approve(
            msg.sender,
            spender,
            _allowances[msg.sender][spender].add(addedValue)
        );
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        virtual
        returns (bool)
    {
        _approve(
            msg.sender,
            spender,
            _allowances[msg.sender][spender].sub(
                subtractedValue,
                'ERC20: decreased allowance below zero'
            )
        );
        return true;
    }

    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal virtual {
        require(sender != address(0), 'ERC20: transfer from the zero address');
        require(recipient != address(0), 'ERC20: transfer to the zero address');

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(
            amount,
            'ERC20: transfer amount exceeds balance'
        );
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    function _mint(address account_, uint256 ammount_) internal virtual {
        require(account_ != address(0), 'ERC20: mint to the zero address');
        _beforeTokenTransfer(address(this), account_, ammount_);
        _totalSupply = _totalSupply.add(ammount_);
        _balances[account_] = _balances[account_].add(ammount_);
        emit Transfer(address(this), account_, ammount_);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), 'ERC20: burn from the zero address');

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(
            amount,
            'ERC20: burn amount exceeds balance'
        );
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), 'ERC20: approve from the zero address');
        require(spender != address(0), 'ERC20: approve to the zero address');

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function _beforeTokenTransfer(
        address from_,
        address to_,
        uint256 amount_
    ) internal virtual {}
}

interface IERC2612Permit {
    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    function nonces(address owner) external view returns (uint256);
}

abstract contract ERC20Permit is ERC20, IERC2612Permit {
    using Counters for Counters.Counter;

    mapping(address => Counters.Counter) private _nonces;

    // keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant PERMIT_TYPEHASH =
        0x6e71edae12b1b97f4d1f60370fef10105fa2faae0126114a169c64845d6126c9;

    bytes32 public DOMAIN_SEPARATOR;

    constructor() {
        uint256 chainID;
        assembly {
            chainID := chainid()
        }

        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256(
                    'EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)'
                ),
                keccak256(bytes(name())),
                keccak256(bytes('1')), // Version
                chainID,
                address(this)
            )
        );
    }

    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) public virtual override {
        require(block.timestamp <= deadline, 'Permit: expired deadline');

        bytes32 hashStruct = keccak256(
            abi.encode(
                PERMIT_TYPEHASH,
                owner,
                spender,
                amount,
                _nonces[owner].current(),
                deadline
            )
        );

        bytes32 _hash = keccak256(
            abi.encodePacked(uint16(0x1901), DOMAIN_SEPARATOR, hashStruct)
        );

        address signer = ecrecover(_hash, v, r, s);
        require(
            signer != address(0) && signer == owner,
            'ZeroSwapPermit: Invalid signature'
        );

        _nonces[owner].increment();
        _approve(owner, spender, amount);
    }

    function nonces(address owner) public view override returns (uint256) {
        return _nonces[owner].current();
    }
}

// File: contracts/types/Ownable.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

interface IOwnable {
    function owner() external view returns (address);

    function renounceManagement() external;

    function pushManagement(address newOwner_) external;

    function pullManagement() external;
}

contract Ownable is IOwnable {
    address internal _owner;
    address internal _newOwner;

    event OwnershipPushed(
        address indexed previousOwner,
        address indexed newOwner
    );
    event OwnershipPulled(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        _owner = msg.sender;
        emit OwnershipPushed(address(0), _owner);
    }

    function owner() public view override returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == msg.sender, 'Ownable: caller is not the owner');
        _;
    }

    function renounceManagement() public virtual override onlyOwner {
        emit OwnershipPushed(_owner, address(0));
        _owner = address(0);
    }

    function pushManagement(address newOwner_)
        public
        virtual
        override
        onlyOwner
    {
        require(
            newOwner_ != address(0),
            'Ownable: new owner is the zero address'
        );
        emit OwnershipPushed(_owner, newOwner_);
        _newOwner = newOwner_;
    }

    function pullManagement() public virtual override {
        require(msg.sender == _newOwner, 'Ownable: must be new owner to pull');
        emit OwnershipPulled(_owner, _newOwner);
        _owner = _newOwner;
    }
}

// File: contracts/libraries/SafeERC20.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

import '../interfaces/IERC20.sol';

import './SafeMath.sol';
import './Counters.sol';
import './Address.sol';

library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(token.transfer.selector, to, value)
        );
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(token.transferFrom.selector, from, to, value)
        );
    }

    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            'SafeERC20: approve from non-zero to non-zero allowance'
        );
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(token.approve.selector, spender, value)
        );
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(
            value
        );
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(
                token.approve.selector,
                spender,
                newAllowance
            )
        );
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(
            value,
            'SafeERC20: decreased allowance below zero'
        );
        _callOptionalReturn(
            token,
            abi.encodeWithSelector(
                token.approve.selector,
                spender,
                newAllowance
            )
        );
    }

    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        bytes memory returndata = address(token).functionCall(
            data,
            'SafeERC20: low-level call failed'
        );
        if (returndata.length > 0) {
            // Return data is optional
            // solhint-disable-next-line max-line-length
            require(
                abi.decode(returndata, (bool)),
                'SafeERC20: ERC20 operation did not succeed'
            );
        }
    }
}

// File: contracts/interfaces/IERC20.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity >=0.5.0;

interface IERC20 {
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
    event Transfer(address indexed from, address indexed to, uint256 value);

    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);

    function totalSupply() external view returns (uint256);

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

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

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

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

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

interface IERC20Mintable {
    function mint(uint256 amount_) external;

    function mint(address account_, uint256 ammount_) external;
}

// File: contracts/libraries/SafeMath.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, 'SafeMath: addition overflow');

        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, 'SafeMath: subtraction overflow');
    }

    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

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

        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, 'SafeMath: division by 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;
    }

    function sqrrt(uint256 a) internal pure returns (uint256 c) {
        if (a > 3) {
            c = a;
            uint256 b = add(div(a, 2), 1);
            while (b < c) {
                c = b;
                b = div(add(div(a, b), b), 2);
            }
        } else if (a != 0) {
            c = 1;
        }
    }
}

// File: contracts/libraries/Counters.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

import './SafeMath.sol';

library Counters {
    using SafeMath for uint256;

    struct Counter {
        uint256 _value; // default: 0
    }

    function current(Counter storage counter) internal view returns (uint256) {
        return counter._value;
    }

    function increment(Counter storage counter) internal {
        counter._value += 1;
    }

    function decrement(Counter storage counter) internal {
        counter._value = counter._value.sub(1);
    }
}

// File: contracts/libraries/Address.sol



// SPDX-License-Identifier: AGPL-3.0-or-later
pragma solidity 0.7.5;

library Address {
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    function sendValue(address payable recipient, uint256 amount) internal {
        require(
            address(this).balance >= amount,
            'Address: insufficient balance'
        );

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{value: amount}('');
        require(
            success,
            'Address: unable to send value, recipient may have reverted'
        );
    }

    function functionCall(address target, bytes memory data)
        internal
        returns (bytes memory)
    {
        return functionCall(target, data, 'Address: low-level call failed');
    }

    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return
            functionCallWithValue(
                target,
                data,
                value,
                'Address: low-level call with value failed'
            );
    }

    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(
            address(this).balance >= value,
            'Address: insufficient balance for call'
        );
        require(isContract(target), 'Address: call to non-contract');

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{value: value}(
            data
        );
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _functionCallWithValue(
        address target,
        bytes memory data,
        uint256 weiValue,
        string memory errorMessage
    ) private returns (bytes memory) {
        require(isContract(target), 'Address: call to non-contract');

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{value: weiValue}(
            data
        );
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }

    function functionStaticCall(address target, bytes memory data)
        internal
        view
        returns (bytes memory)
    {
        return
            functionStaticCall(
                target,
                data,
                'Address: low-level static call failed'
            );
    }

    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), 'Address: static call to non-contract');

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function functionDelegateCall(address target, bytes memory data)
        internal
        returns (bytes memory)
    {
        return
            functionDelegateCall(
                target,
                data,
                'Address: low-level delegate call failed'
            );
    }

    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), 'Address: delegate call to non-contract');

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) private pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            if (returndata.length > 0) {
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }

    function addressToString(address _address)
        internal
        pure
        returns (string memory)
    {
        bytes32 _bytes = bytes32(uint256(_address));
        bytes memory HEX = '0123456789abcdef';
        bytes memory _addr = new bytes(42);

        _addr[0] = '0';
        _addr[1] = 'x';

        for (uint256 i = 0; i < 20; i++) {
            _addr[2 + i * 2] = HEX[uint8(_bytes[i + 12] >> 4)];
            _addr[3 + i * 2] = HEX[uint8(_bytes[i + 12] & 0x0f)];
        }

        return string(_addr);
    }
}