// SPDX-License-Identifier: MIT
// File: Kamada.sol


pragma solidity 0.8.17;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        _setOwner(_msgSender());
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public virtual onlyOwner {
        _setOwner(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address recipient, uint256 amount)
        external
        returns (bool);

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

interface IERC20Metadata is IERC20 {
    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);
}

contract Kamada is Context, IERC20, IERC20Metadata, Ownable {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) private _isBlacklisted;

    uint256 private _totalSupply = 0;
    uint256 private _initialSupply = 1_000_000_000;

    string private constant _name = "DAICHI KAMADA";
    string private constant _symbol = "KAMADA";
    uint8 private constant _decimals = 18;

    uint256 public _transactionFee = 4;
    address public constant _feeWallet =
        0x420948DCfb545C05B56A9ca8133C3A034E115A21;

    constructor() {
        _mint(_msgSender(), _initialSupply * 10**uint256(_decimals));
        emit Transfer(address(0), msg.sender, _initialSupply);
    }

    function name() public view virtual override returns (string memory) {
        return _name;
    }

    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual override returns (uint8) {
        return _decimals;
    }

    function totalSupply() public view virtual 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(_msgSender(), 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(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(
            currentAllowance >= amount,
            "ERC20: transfer amount exceeds allowance"
        );
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }

        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender] + addedValue
        );
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue)
        public
        virtual
        returns (bool)
    {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }

        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);

        uint256 senderBalance = _balances[sender];
        require(
            senderBalance >= amount,
            "ERC20: transfer amount exceeds balance"
        );

        uint256 transactionFee = calculateFee(amount);
        uint256 transferAmount = amount;
        if (sender != owner() && recipient != owner()) {
            transferAmount = transferAmount - transactionFee;
            _balances[_feeWallet] = _balances[_feeWallet] + transactionFee;
        }
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += transferAmount;

        emit Transfer(sender, recipient, amount);

        _afterTokenTransfer(sender, recipient, amount);
    }

    function calculateFee(uint256 _amount) private view returns (uint256) {
        return (_amount * _transactionFee) / 100;
    }

    function setFeePercentage(uint256 transactionFee) external onlyOwner {
        require(transactionFee <= 100);
        _transactionFee = transactionFee;
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0));

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(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) internal virtual {
        require(
            !isBlacklisted(from) && !isBlacklisted(to),
            "Transfer from or to blacklisted address"
        );
    }

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function excludeFromBlacklist(address account) public onlyOwner {
        _isBlacklisted[account] = false;
    }

    function includeInBlacklist(address account) public onlyOwner {
        _isBlacklisted[account] = true;
    }

    function isBlacklisted(address account) public view returns (bool) {
        return _isBlacklisted[account];
    }

    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }
}