// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

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

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

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

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @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.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: contracts/interface/IDistributor.sol



// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.19;

interface IDistributor {
    function distribute() external;

    function nextRewardAt(uint256 _rate) external view returns (uint256);

    function nextRewardFor(address _recipient) external view returns (uint256);

    function addRecipient(address _recipient, uint256 _rewardRate) external;

    function removeRecipient(uint256 _index) external;

    function setAdjustment(
        uint256 _index,
        bool _add,
        uint256 _rate,
        uint256 _target
    ) external;
}

// File: contracts/interface/IHATE.sol



import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";

pragma solidity 0.8.19;

interface IHATE is IERC20Metadata {
    function mint(address to_, uint256 amount_) external;
}
// File: contracts/interface/IHATETreasury.sol



pragma solidity >=0.7.5;

interface IHATETreasury {
    function mintHATE(address to_, uint256 amount_) external;
    function valueOfToken(address _principalToken, uint _amount) external view returns (uint value_);
    function HATE() external view returns (address);
}
// File: contracts/StakingDistributor.sol



// SPDX-License-Identifier: AGPL-3.0
pragma solidity 0.8.19;

import "@openzeppelin/contracts/access/Ownable.sol";
import "./interface/IHATE.sol";
import "./interface/IHATETreasury.sol";
import "./interface/IDistributor.sol";

contract Distributor is IDistributor, Ownable {
    /* ====== VARIABLES ====== */

    IERC20 private immutable HATE;
    IHATETreasury private immutable treasury;
    address private immutable staking;

    mapping(uint256 => Adjust) public adjustments;

    uint256 private immutable rateDenominator = 1_000_000;

    /* ====== 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 _HATE, address _staking) {
        require(_treasury != address(0), "Zero address: Treasury");
        treasury = IHATETreasury(_treasury);
        require(_HATE != address(0), "Zero address: HATE");
        HATE = IHATE(_HATE);
        require(_staking != address(0), "Zero address: Staking");
        staking = _staking;
    }

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

    /**
        @notice send epoch reward to staking contract
     */
    function distribute() external override {
        require(msg.sender == staking, "Only staking");
        // distribute rewards to each recipient
        for (uint256 i = 0; i < info.length; i++) {
            if (info[i].rate > 0) {
                treasury.mintHATE(info[i].recipient, nextRewardAt(info[i].rate)); // mint and send tokens
                adjust(i); // check for adjustment
            }
        }
    }

    /* ====== 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 + adjustment.rate; // raise rate
                if (info[_index].rate >= adjustment.target) {
                    // if target met
                    adjustments[_index].rate = 0; // turn off adjustment
                    info[_index].rate = adjustment.target; // set to target
                }
            } else {
                // if rate should decrease
                if (info[_index].rate > adjustment.rate) {
                    // protect from underflow
                    info[_index].rate = info[_index].rate - adjustment.rate; // lower rate
                } else {
                    info[_index].rate = 0;
                }

                if (info[_index].rate <= adjustment.target) {
                    // if target met
                    adjustments[_index].rate = 0; // turn off adjustment
                    info[_index].rate = adjustment.target; // set to target
                }
            }
        }
    }

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

    /**
        @notice view function for next reward at given rate
        @param _rate uint
        @return uint
     */
    function nextRewardAt(uint256 _rate) public view override returns (uint256) {
        return (HATE.totalSupply() * _rate) / rateDenominator;
    }

    /**
        @notice view function for next reward for specified address
        @param _recipient address
        @return uint
     */
    function nextRewardFor(address _recipient) public view override returns (uint256) {
        uint256 reward;
        for (uint256 i = 0; i < info.length; i++) {
            if (info[i].recipient == _recipient) {
                reward = 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 override onlyOwner {
        require(_recipient != address(0), "Zero address: Recipient");
        require(_rewardRate <= rateDenominator, "Rate cannot exceed denominator");
        info.push(Info({recipient: _recipient, rate: _rewardRate}));
    }

    /**
        @notice removes recipient for distributions
        @param _index uint
     */
    function removeRecipient(uint256 _index) external override onlyOwner {
        require(info[_index].recipient != address(0), "Recipient does not exist");
        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 override onlyOwner {
        require(info[_index].recipient != address(0), "Recipient does not exist");

        if (!_add) {
            require(_rate <= info[_index].rate, "Cannot decrease rate by more than it already is");
        }

        adjustments[_index] = Adjust({add: _add, rate: _rate, target: _target});
    }
}