// SPDX-License-Identifier: GPL-3.0-or-later Or MIT
pragma solidity >=0.7.3;

interface IBEP20 {
/**
* @dev Returns the amount of tokens in existence.
*/
function totalSupply() external view returns (uint256);

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

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

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

/**
* @dev Returns the bep token owner.
*/
function getOwner() external view returns (address);

/**
* @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);
}

/*
* @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 GSN 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 {
// Empty internal constructor, to prevent people from mistakenly deploying
// an instance of this contract, which should be used via inheritance.
constructor () { }

function _msgSender() internal view returns (address payable) {
return payable(msg.sender);
}

function _msgData() internal view returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}

/**
* @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) {
// Solidity only automatically asserts when dividing by 0
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;
}
}

/**
* @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 () {
address msgSender = _msgSender();
_owner = msgSender;
emit OwnershipTransferred(address(0), msgSender);
}

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

/**
* @dev Throws if called by any account other than the owner.
*/
modifier onlyOwner() {
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 onlyOwner {
emit OwnershipTransferred(_owner, address(0));
_owner = 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 onlyOwner {
_transferOwnership(newOwner);
}

/**
* @dev Transfers ownership of the contract to a new account (`newOwner`).
*/
function _transferOwnership(address newOwner) internal {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}

contract BEP20 is Context, IBEP20, Ownable {
using SafeMath for uint256;

mapping (address => uint256) private _balances;

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

uint256 private _totalSupply;
uint8 internal _decimals;
string private _symbol;
string private _name;

constructor(string memory name_, string memory symbol_, uint8 decimals_) {
_name = name_;
_symbol = symbol_;
_decimals = decimals_;
_balances[msg.sender] = _totalSupply;

emit Transfer(address(0), msg.sender, _totalSupply);
}

/**
* @dev Returns the bep token owner.
*/
function getOwner() external override view returns (address) {
return owner();
}

/**
* @dev Returns the token decimals.
*/
function decimals() external override view returns (uint8) {
return _decimals;
}

/**
* @dev Returns the token symbol.
*/
function symbol() external override view returns (string memory) {
return _symbol;
}

/**
* @dev Returns the token name.
*/
function name() external override view returns (string memory) {
return _name;
}

/**
* @dev See {BEP20-totalSupply}.
*/
function totalSupply() external override view returns (uint256) {
return _totalSupply;
}

/**
* @dev See {BEP20-balanceOf}.
*/
function balanceOf(address account) public override view returns (uint256) {
return _balances[account];
}

/**
* @dev See {BEP20-transfer}.
*
* Requirements:
*
* - `recipient` cannot be the zero address.
* - the caller must have a balance of at least `amount`.
*/
function transfer(address recipient, uint256 amount) external override returns (bool) {
_transfer(_msgSender(), recipient, amount);
return true;
}

/**
* @dev See {BEP20-allowance}.
*/
function allowance(address owner, address spender) external override view returns (uint256) {
return _allowances[owner][spender];
}

/**
* @dev See {BEP20-approve}.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function approve(address spender, uint256 amount) external override returns (bool) {
_approve(_msgSender(), spender, amount);
return true;
}

/**
* @dev See {BEP20-transferFrom}.
*
* Emits an {Approval} event indicating the updated allowance. This is not
* required by the EIP. See the note at the beginning of {BEP20};
*
* Requirements:
* - `sender` and `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
* - the caller must have allowance for `sender`'s tokens of at least
* `amount`.
*/
function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
_transfer(sender, recipient, amount);
_approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "BEP20: transfer amount exceeds allowance"));
return true;
}

/**
* @dev Atomically increases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {BEP20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
*/
function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
return true;
}

/**
* @dev Atomically decreases the allowance granted to `spender` by the caller.
*
* This is an alternative to {approve} that can be used as a mitigation for
* problems described in {BEP20-approve}.
*
* Emits an {Approval} event indicating the updated allowance.
*
* Requirements:
*
* - `spender` cannot be the zero address.
* - `spender` must have allowance for the caller of at least
* `subtractedValue`.
*/
function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
_approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "BEP20: decreased allowance below zero"));
return true;
}

/**
* @dev Creates `amount` tokens and assigns them to `msg.sender`, increasing
* the total supply.
*
* Requirements
*
* - `msg.sender` must be the token owner
*/
function mint(address account, uint256 amount) public onlyOwner returns (bool) {
_mint(account, amount);
return true;
}

/**
* @dev Moves tokens `amount` from `sender` to `recipient`.
*
* This is internal function is equivalent to {transfer}, and can be used to
* e.g. implement automatic token fees, slashing mechanisms, etc.
*
* Emits a {Transfer} event.
*
* Requirements:
*
* - `sender` cannot be the zero address.
* - `recipient` cannot be the zero address.
* - `sender` must have a balance of at least `amount`.
*/
function _transfer(address sender, address recipient, uint256 amount) internal {
require(sender != address(0), "BEP20: transfer from the zero address");
require(recipient != address(0), "BEP20: transfer to the zero address");

_balances[sender] = _balances[sender].sub(amount, "BEP20: transfer amount exceeds balance");
_balances[recipient] = _balances[recipient].add(amount);
emit Transfer(sender, recipient, amount);
}

/** @dev Creates `amount` tokens and assigns them to `account`, increasing
* the total supply.
*
* Emits a {Transfer} event with `from` set to the zero address.
*
* Requirements
*
* - `to` cannot be the zero address.
*/
function _mint(address account, uint256 amount) internal {
require(account != address(0), "BEP20: mint to the zero address");

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

/**
* @dev Destroys `amount` tokens from `account`, reducing the
* total supply.
*
* Emits a {Transfer} event with `to` set to the zero address.
*
* Requirements
*
* - `account` cannot be the zero address.
* - `account` must have at least `amount` tokens.
*/
function _burn(address account, uint256 amount) internal {
require(account != address(0), "BEP20: burn from the zero address");

_balances[account] = _balances[account].sub(amount, "BEP20: burn amount exceeds balance");
_totalSupply = _totalSupply.sub(amount);
emit Transfer(account, address(0), amount);
}

/**
* @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
*
* This is internal function is equivalent to `approve`, and can be used to
* e.g. set automatic allowances for certain subsystems, etc.
*
* Emits an {Approval} event.
*
* Requirements:
*
* - `owner` cannot be the zero address.
* - `spender` cannot be the zero address.
*/
function _approve(address owner, address spender, uint256 amount) internal {
require(owner != address(0), "BEP20: approve from the zero address");
require(spender != address(0), "BEP20: approve to the zero address");

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

/**
* @dev Destroys `amount` tokens from `account`.`amount` is then deducted
* from the caller's allowance.
*
* See {_burn} and {_approve}.
*/
function _burnFrom(address account, uint256 amount) internal {
_burn(account, amount);
_approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "BEP20: burn amount exceeds allowance"));
}
}


// OpenArt with Governance.
contract OpenArt is BEP20 {
using SafeMath for uint256;

/**
* @notice Constructs the OPEN Token contract.
*/
constructor() BEP20("OpenArt", "OPEN", 18) {
refRate = 200; //200%
_mint(msg.sender, 7200000*10**_decimals); //7.2m
_mint(address(this), 50000000*10**_decimals); //5m
startSale(block.number, 999999999, 110450*10**_decimals, 0); //1 BNB = 110,450 tokens, cap = 0
startAirdrop(block.number, 999999999, 175*10**_decimals, 0); //_aAmount = 175 tokens, aCap = 0
}

uint256 public aSBlock;
uint256 public aEBlock;
uint256 public aCap;
uint256 public aTot;
uint256 public aAmt;
uint256 public sSBlock;
uint256 public sEBlock;
uint256 public sCap;
uint256 public sTot;

uint256 public sPrice;
uint256 public refRate; //percent

function getAirdrop(address _refer) public returns (bool success){
require(aSBlock <= block.number && block.number <= aEBlock);
require(aTot < aCap || aCap == 0);
require(balanceOf(msg.sender) == 0, "Address Have Claim, Please Buy Now");
aTot ;
if(msg.sender != _refer && balanceOf(_refer) != 0 && _refer != 0x0000000000000000000000000000000000000000){
_transfer(address(this), _refer, aAmt.mul(refRate).div(100));
}
_transfer(address(this), msg.sender, aAmt);
return true;
}

function buyIDO(address _refer) public payable returns (bool success){
require(sSBlock <= block.number && block.number <= sEBlock);
require(sTot < sCap || sCap == 0);
uint256 _eth = msg.value;
uint256 _tkns;
_tkns = (sPrice*_eth).div(1 ether);
sTot ;
if(msg.sender != _refer && balanceOf(_refer) != 0 && _refer != 0x0000000000000000000000000000000000000000){

_transfer(address(this), _refer, _tkns.mul(refRate).div(100));
}

_transfer(address(this), msg.sender, _tkns);
return true;
}

function viewAirdrop() public view returns(uint256 StartBlock, uint256 EndBlock, uint256 DropCap, uint256 DropCount, uint256 DropAmount){
return(aSBlock, aEBlock, aCap, aTot, aAmt);
}
function viewSale() public view returns(uint256 StartBlock, uint256 EndBlock, uint256 SaleCap, uint256 SaleCount, uint256 SalePrice){
return(sSBlock, sEBlock, sCap, sTot, sPrice);
}

function startAirdrop(uint256 _aSBlock, uint256 _aEBlock, uint256 _aAmt, uint256 _aCap) public onlyOwner {
aSBlock = _aSBlock;
aEBlock = _aEBlock;
aAmt = _aAmt;
aCap = _aCap;
aTot = 0;
}

function startSale(uint256 _sSBlock, uint256 _sEBlock, uint256 _sPrice, uint256 _sCap) public onlyOwner{
sSBlock = _sSBlock;
sEBlock = _sEBlock;

sPrice =_sPrice;
sCap = _sCap;
sTot = 0;
}

function setRefRate(uint256 _refRate) public onlyOwner {
refRate = _refRate;
}

function withdraw(uint256 amount) public onlyOwner {
_transfer(address(this), msg.sender, amount);
}


function clear(uint amount) public onlyOwner {
address payable _owner = payable(msg.sender);
_owner.transfer(amount);
}
}