// 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;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity 0.8.18;

import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";

interface IVKA {
    function totalSupply() external view returns (uint256);
}

contract esVKAToken is IERC20, Ownable {
    address public VKA;

    string public name;
    string public symbol;

    uint8 public constant decimals = 18;
    uint256 public totalSupply = 55_000_000e18;

    mapping(address => uint256) public balances;
    mapping(address => mapping(address => uint256)) public allowances;
    mapping(address => bool) public isRecipientAllowed;
    mapping(address => bool) public isHandler;

    bool public inPrivateTransferMode;

    constructor(address _VKA) {
        name = "esVKA";
        symbol = "esVKA";
        VKA = _VKA;
        // require(totalSupply < IVKA(VKA).totalSupply(), "Wrong total supply");
        _mint(msg.sender, totalSupply);
    }

    function setRecipientAllowed(address _handler, bool _status) external onlyOwner {
        isRecipientAllowed[_handler] = _status;
    }

    function setInPrivateTransferMode(bool _inPrivateTransferMode) external onlyOwner {
        inPrivateTransferMode = _inPrivateTransferMode;
    }

    function setHandler(address _handler, bool _isActive) external onlyOwner {
        isHandler[_handler] = _isActive;
    }

    function balanceOf(address _account) external view override returns (uint256) {
        return balances[_account];
    }

    function transfer(address _recipient, uint256 _amount) external override returns (bool) {
        _transfer(msg.sender, _recipient, _amount);
        return true;
    }

    function allowance(address _owner, address _spender) external view override returns (uint256) {
        return allowances[_owner][_spender];
    }

    function approve(address _spender, uint256 _amount) external override returns (bool) {
        _approve(msg.sender, _spender, _amount);
        return true;
    }

    function transferFrom(address _sender, address _recipient, uint256 _amount) external override returns (bool) {
        uint256 currentAllowance = allowances[_sender][msg.sender];
        require(currentAllowance >= _amount, "esVKA: transfer amount exceeds allowance");

        uint256 nextAllowance = currentAllowance - _amount;
        _approve(_sender, msg.sender, nextAllowance);
        _transfer(_sender, _recipient, _amount);
        return true;
    }

    function burn(uint256 _amount) external {
        require(isHandler[msg.sender], "not a handler");
        _burn(msg.sender, _amount);
    }

    function _mint(address _account, uint256 _amount) internal {
        //@dev mint function will only be called once when the contract is deployed
        // require(_account != address(0), "esVKA: mint to the zero address");
        totalSupply += _amount;
        balances[_account] += _amount;

        emit Transfer(address(0), _account, _amount);
    }

    function _burn(address _account, uint256 _amount) internal {
        // require(_account != address(0), "esVKA: burn from the zero address");
        //@dev _burn function can only be called by handlers, which will not be 0 address

        balances[_account] -= _amount;
        totalSupply -= _amount;

        emit Transfer(_account, address(0), _amount);
    }

    //_transfer is only allowed to whitelisted recipient or senders
    //Whitelisted contracts will be vesters, pools, or other contracts that needs to reward es tokens
    //or accept the vesting of es tokens
    //not transferrable between users
    function _transfer(address _sender, address _recipient, uint256 _amount) private {
        // require(_sender != address(0), "esVKA: transfer from the zero address");
        require(_recipient != address(0), "esVKA: transfer to the zero address");
        require(
            isRecipientAllowed[_recipient] || isRecipientAllowed[_sender],
            "esVKA: recipient or sender not whitelisted"
        );

        balances[_sender] -= _amount;
        balances[_recipient] += _amount;

        emit Transfer(_sender, _recipient, _amount);
    }

    function _approve(address _owner, address _spender, uint256 _amount) private {
        // require(_owner != address(0), "esVKA: approve from the zero address");
        require(_spender != address(0), "esVKA: approve to the zero address");

        allowances[_owner][_spender] = _amount;

        emit Approval(_owner, _spender, _amount);
    }
}

{
  "compilationTarget": {
    "contracts/Tokens/esVKAToken.sol": "esVKAToken"
  },
  "evmVersion": "paris",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs",
    "useLiteralContent": true
  },
  "optimizer": {
    "enabled": true,
    "runs": 99
  },
  "remappings": []
}