// 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 @openzeppelin/contracts/access/Ownable.sol@v4.8.1

// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

/**
 * @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/IERC20.sol@v4.8.1

// 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/math/SafeMath.sol@v4.8.1

// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // 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 (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @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) {
        return a + b;
    }

    /**
     * @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 a - b;
    }

    /**
     * @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) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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 a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File contracts/OEBSubscription.sol

pragma solidity 0.8.19;

contract OEBSubscription is Ownable {
    using SafeMath for uint256;

    mapping(address => uint256) public userAmount;
    mapping(address => uint256) public claimTimes;

    uint256 public constant MAX_AMOUNT = 2500 * 10 ** 6;
    uint256 public constant HARD_CAP = 330000 * 10 ** 6;
    uint256 public constant TOTAL_OEB_FOR_SALE = 3150000 * 1e18;
    uint256 public RATE = TOTAL_OEB_FOR_SALE.div(330000); // 1 USDC = 9.545... OEB
    uint256 public constant TGE_PERCENT = 500; // 50%
    uint256 public constant CYCLE_PERCENT = 100; // 10%
    uint256 public constant DIV_PERCENT = 1000;
    uint256 public constant VESTING_CYCLE = 30 days;

    uint256 public raised;
    uint256 public startTime;
    uint256 public duration;
    uint256 public releasedTime;
    uint256 public emergencyDuration;

    IERC20 public oeb;
    IERC20 public usdc;

    event Claim(address indexed user, uint256 amount);
    event EmergencyWithdraw(address indexed user, uint256 amount);
    event Buy(address indexed user, uint256 amount);
    event OpenClaim();

    constructor(address _oeb, address _usdc) {
        oeb = IERC20(_oeb);
        usdc = IERC20(_usdc);
    }

    function getAmountUSDCCanBuy(address _user) public view returns (uint256) {
        uint256 amount = userAmount[_user];
        if (amount == 0) {
            return 0;
        }
        uint256 rateSubUSDC = amount.mul(DIV_PERCENT).div(raised);
        uint256 amountUSDC = rateSubUSDC.mul(HARD_CAP).div(DIV_PERCENT);
        if (amountUSDC > MAX_AMOUNT) {
            return MAX_AMOUNT;
        }
        return amountUSDC;
    }

    function deposit(uint256 _amount) external {
        require(block.timestamp >= startTime, 'Not start');
        require(block.timestamp <= startTime.add(duration), 'Ended');
        require(_amount > 0, 'Amount must be greater than 0');

        usdc.transferFrom(_msgSender(), address(this), _amount);
        raised = raised.add(_amount);
        userAmount[_msgSender()] = userAmount[_msgSender()].add(_amount);

        emit Buy(_msgSender(), _amount);
    }

    function emergencyWhithdraw() external {
        require(block.timestamp < startTime.add(emergencyDuration), "Can't withdraw");
        require(block.timestamp <= startTime.add(duration), 'Ended');
        require(userAmount[_msgSender()] > 0, 'Invalid amount');

        raised = raised.sub(userAmount[_msgSender()]);

        usdc.transfer(_msgSender(), userAmount[_msgSender()]);
        userAmount[_msgSender()] = 0;

        emit EmergencyWithdraw(_msgSender(), userAmount[_msgSender()]);
    }

    function claim() external {
        require(block.timestamp >= startTime.add(duration), 'Not ended');
        require(userAmount[_msgSender()] > 0, 'Invalid amount');
        require(claimTimes[_msgSender()] < 6, 'Claimed 6 times');

        uint256 amountUSDC = getAmountUSDCCanBuy(_msgSender());
        uint256 amountOEB = amountUSDC.mul(RATE).div(1e6);

        uint256 time = userClaimTime(_msgSender());

        require(time > 0 && time < block.timestamp, 'Not released cycle');

        if (claimTimes[_msgSender()] == 0) {
            amountOEB = amountOEB.mul(TGE_PERCENT).div(DIV_PERCENT);
            uint256 usdcRefund = userAmount[_msgSender()].sub(amountUSDC);
            if (usdcRefund > 0) {
                usdc.transfer(_msgSender(), usdcRefund);
            }
        } else {
            amountOEB = amountOEB.mul(CYCLE_PERCENT).div(DIV_PERCENT);
        }

        oeb.transfer(_msgSender(), amountOEB);

        claimTimes[_msgSender()] = claimTimes[_msgSender()].add(1);

        emit Claim(_msgSender(), amountOEB);
    }

    function userClaimTime(address _user) public view returns (uint256) {
        if (releasedTime == 0 || claimTimes[_user] > 5) return 0;
        return releasedTime + claimTimes[_user] * VESTING_CYCLE;
    }

    function openClaim(uint256 _time) external onlyOwner {
        releasedTime = _time;
        emit OpenClaim();
    }

    function settings(uint256 _startTime, uint256 _duration, uint256 _emergencyDuration) external onlyOwner {
        startTime = _startTime;
        duration = _duration;
        emergencyDuration = _emergencyDuration;
    }

    function safuToken() external onlyOwner {
        oeb.transfer(_msgSender(), oeb.balanceOf(address(this)));
    }

    function safuUSDC(uint256 _amount) external onlyOwner {
        usdc.transfer(_msgSender(), _amount);
    }
}