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



// 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);
    }
}

// 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 v4.9.0) (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);
}

// 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/ERC20Reflections.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.18;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "@openzeppelin/contracts/utils/Context.sol";

/**
 * @dev This contract is derived from the ERC20.sol by openzeppelin and the
 reflection token contract by CoinTools. The contract removes liquidity and
 burn fee and only redistributes tokens to holders. This contract has improvements
 in terms of gas efficiency, security, and readibility.
 */
contract ERC20Reflections is Context, IERC20, IERC20Metadata, Ownable {
    uint256 private constant MAX = ~uint256(0);
    uint256 private _rTotalSupply; // total supply in r-space
    uint256 private _rLastTxFee;
    uint256 private immutable _tTotalSupply; // total supply in t-space
    string private _name;
    string private _symbol;
    address[] private _excludedFromReward;

    uint256 public txFee = 200; // 200 => 2%
    uint256 public accumulatedFees;

    mapping(address => uint256) private _rBalances; // balances in r-space
    mapping(address => uint256) private _tBalances; // balances in t-space
    mapping(address => mapping(address => uint256)) private _allowances;

    mapping(address => bool) public isExcludedFromFee;
    mapping(address => bool) public isExcludedFromReward;

    event SetFee(uint256 value);

    constructor(string memory name_, string memory symbol_, address owner_) {
        _name = name_;
        _symbol = symbol_;
        _tTotalSupply = 1_000_000_000 * 10 ** decimals();
        excludeFromFee(owner_);
        excludeFromFee(address(this));
        _mint(owner_, _tTotalSupply); // for deployer use msg.sender
        _transferOwnership(owner_);
    }

    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 18;
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _tTotalSupply;
    }

    function balanceOf(
        address account
    ) public view virtual override returns (uint256) {
        uint256 rate = _conversionRate();
        return _rBalances[account] / rate;
    }

    function transfer(
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(msg.sender, to, amount);
        return true;
    }

    function allowance(
        address account,
        address spender
    ) public view virtual override returns (uint256) {
        return _allowances[account][spender];
    }

    function approve(
        address spender,
        uint256 amount
    ) public virtual override returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    function increaseAllowance(
        address spender,
        uint256 addedValue
    ) public virtual returns (bool) {
        _approve(
            msg.sender,
            spender,
            allowance(msg.sender, spender) + addedValue
        );
        return true;
    }

    function decreaseAllowance(
        address spender,
        uint256 subtractedValue
    ) public virtual returns (bool) {
        uint256 currentAllowance = allowance(msg.sender, spender);
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(msg.sender, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    function setTransactionFee(uint256 newTxFee) public onlyOwner {
        txFee = newTxFee;
        emit SetFee(txFee);
    }

    function excludeFromReward(address account) public onlyOwner {
        require(!isExcludedFromReward[account], "Address already excluded");
        require(_excludedFromReward.length < 100, "Excluded list is too long");

        if (_rBalances[account] > 0) {
            uint256 rate = _conversionRate();
            _tBalances[account] = _rBalances[account] / rate;
        }
        isExcludedFromReward[account] = true;
        _excludedFromReward.push(account);
    }

    function includeInReward(address account) public onlyOwner {
        require(isExcludedFromReward[account], "Account is already included");
        uint256 nExcluded = _excludedFromReward.length;
        for (uint256 i = 0; i < nExcluded; i++) {
            if (_excludedFromReward[i] == account) {
                _excludedFromReward[i] = _excludedFromReward[
                    _excludedFromReward.length - 1
                ];
                _tBalances[account] = 0;
                isExcludedFromReward[account] = false;
                _excludedFromReward.pop();
                break;
            }
        }
    }

    function excludeFromFee(address account) public onlyOwner {
        isExcludedFromFee[account] = true;
    }

    function includeInFee(address account) public onlyOwner {
        isExcludedFromFee[account] = false;
    }

    // withdraw tokens from contract (only owner)
    function withdrawTokens(
        address tokenAddress,
        address receiverAddress
    ) external onlyOwner returns (bool success) {
        IERC20 tokenContract = IERC20(tokenAddress);
        uint256 amount = tokenContract.balanceOf(address(this));
        return tokenContract.transfer(receiverAddress, amount);
    }

    function _conversionRate() private view returns (uint256) {
        uint256 rSupply = _rTotalSupply;
        uint256 tSupply = _tTotalSupply;

        uint256 nExcluded = _excludedFromReward.length;
        for (uint256 i = 0; i < nExcluded; i++) {
            rSupply = rSupply - _rBalances[_excludedFromReward[i]];
            tSupply = tSupply - _tBalances[_excludedFromReward[i]];
        }
        if (rSupply < _rTotalSupply / _tTotalSupply) {
            rSupply = _rTotalSupply;
            tSupply = _tTotalSupply;
        }
        // rSupply always > tSupply (no precision loss)
        uint256 rate = rSupply / tSupply;
        return rate;
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");

        _beforeTokenTransfer(from, to, amount);

        uint256 _txFee;
        if (isExcludedFromFee[from] || isExcludedFromFee[to]) {
            _txFee = 0;
        } else {
            _txFee = txFee;
        }

        // reflect fee
        unchecked {
            // can never go below zero because rTxFee percentage of
            // _rTotalSupply
            _rTotalSupply = _rTotalSupply - _rLastTxFee;
        }
        
        // calc t-values
        uint256 tAmount = amount;
        uint256 tTxFee = (tAmount * _txFee) / 10000; // fee = 200 / 10000 = 2
        uint256 tTransferAmount = tAmount - tTxFee;

        // calc r-values
        uint256 rate = _conversionRate();
        uint256 rTxFee = tTxFee * rate;
        uint256 rAmount = tAmount * rate;
        uint256 rTransferAmount = rAmount - rTxFee;

        // check balances
        uint256 rFromBalance = _rBalances[from];
        uint256 tFromBalance = _tBalances[from];

        if (isExcludedFromReward[from]) {
            require(
                tFromBalance >= tAmount,
                "ERC20: transfer amount exceeds balance"
            );
        } else {
            require(
                rFromBalance >= rAmount,
                "ERC20: transfer amount exceeds balance"
            );
        }

        // Overflow not possible: the sum of all balances is capped by
        // rTotalSupply and tTotalSupply, and the sum is preserved by
        // decrementing then incrementing.
        unchecked {
            // udpate balances in r-space
            _rBalances[from] = rFromBalance - rAmount;
            _rBalances[to] += rTransferAmount;

            // update balances in t-space
            if (isExcludedFromReward[from] && isExcludedFromReward[to]) {
                _tBalances[from] = tFromBalance - tAmount;
                _tBalances[to] += tTransferAmount;
            } else if (
                isExcludedFromReward[from] && !isExcludedFromReward[to]
            ) {
                _tBalances[from] = tFromBalance - tAmount;
            } else if (
                !isExcludedFromReward[from] && isExcludedFromReward[to]
            ) {
                _tBalances[to] += tTransferAmount;
            }

            // store collected fees
            _rLastTxFee = rTxFee;
            accumulatedFees += tTxFee;
        }

        emit Transfer(from, to, tTransferAmount);

        _afterTokenTransfer(from, to, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _rTotalSupply += (MAX - (MAX % amount));
        unchecked {
            _rBalances[account] += _rTotalSupply;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _approve(
        address account,
        address spender,
        uint256 amount
    ) internal virtual {
        require(account != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[account][spender] = amount;
        emit Approval(account, spender, amount);
    }

    function _spendAllowance(
        address account,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(account, spender);
        if (currentAllowance != type(uint256).max) {
            require(
                currentAllowance >= amount,
                "ERC20: insufficient allowance"
            );
            unchecked {
                _approve(account, spender, currentAllowance - amount);
            }
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}