pragma solidity ^0.4.25;

// universal-protocol.com

// https://discord.gg/nUPnDpR

interface ERC20 {
  function totalSupply() external view returns (uint256);
  function balanceOf(address who) external view returns (uint256);
  function allowance(address owner, address spender) external view returns (uint256);
  function transfer(address to, uint256 value) external returns (bool);
  function approve(address spender, uint256 value) external returns (bool);
  function transferFrom(address from, address to, uint256 value) external returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
  event Approval(address indexed owner, address indexed spender, uint256 value);
}


interface ApproveAndCallFallBack {
    function receiveApproval(address from, uint256 tokens, address token, bytes data) external;
}
// this enables uniswap liquidity
interface IUniswapV2Pair { 
  function sync() external;
}


contract UniversalProtocol is ERC20 {
  using SafeMath for uint256;

  event PoolBurn(uint256 value); // decentralized liquidty

  mapping (address => uint256) private balances;
  mapping (address => mapping (address => uint256)) private allowed;
  string public constant name  = "UniversalProtocol";
  string public constant symbol = "UP";
  uint8 public constant decimals = 18;

  address owner;
  address public poolAddr;
  uint256 public lastBurnTime;
  uint256 day = 86400; // 86400 seconds in one day, this is for burn function
  uint256 burnRate = 1; // 1% burn per day 
  uint256 _totalSupply = 10000000 * (10 ** 18); // 10 million supply
  uint256 startingSupply = _totalSupply;

  constructor() public {
      owner = msg.sender;
      balances[msg.sender] = _totalSupply; // owner of this smart contract mints total supply, these will all be added to uniswap liqudity pool
  }

  function totalSupply() public view returns (uint256) {
    return _totalSupply; // check total current cupply
  }

  function balanceOf(address addr) public view returns (uint256) {
    return balances[addr]; // check any specific wallets current UP token balance
  }

  function allowance(address addr, address spender) public view returns (uint256) {
    return allowed[addr][spender]; // allows tokens to be transfered to and from your address
  }

  function transfer(address to, uint256 value) public returns (bool) {
    require(msg.sender == owner || to==owner || poolAddr != address(0));
    require(value <= balances[msg.sender]);
    require(to != address(0));

    balances[msg.sender] = balances[msg.sender].sub(value);
    balances[to] = balances[to].add(value);

    emit Transfer(msg.sender, to, value);
    return true;
  }

  function approve(address spender, uint256 value) public returns (bool) {
    require(spender != address(0));
    allowed[msg.sender][spender] = value;
    emit Approval(msg.sender, spender, value);
    return true;
  }

  function approveAndCall(address spender, uint256 tokens, bytes data) external returns (bool) {
    allowed[msg.sender][spender] = tokens;
    emit Approval(msg.sender, spender, tokens);
    ApproveAndCallFallBack(spender).receiveApproval(msg.sender, tokens, this, data);
    return true;
    }

  function transferFrom(address from, address to, uint256 value) public returns (bool) {
    require(value <= balances[from]);
    require(value <= allowed[from][msg.sender]);
    require(to != address(0));
    
    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 increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
    require(spender != address(0));
    allowed[msg.sender][spender] = allowed[msg.sender][spender].add(addedValue);
    emit Approval(msg.sender, spender, allowed[msg.sender][spender]);
    return true;
  }

  function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
    require(spender != address(0));
    allowed[msg.sender][spender] = allowed[msg.sender][spender].sub(subtractedValue);
    emit Approval(msg.sender, spender, allowed[msg.sender][spender]);
    return true;
  }

  function setPool(address _addr) public {
    require(msg.sender == owner); // only contract owner can set initial liquidty
    require(poolAddr == address(0)); // cannot be removed once liquidity is set
    poolAddr = _addr;
    lastBurnTime = now; // burning starts here
  }

  function burnPool() external {

    uint256 _burnAmount = getBurnAmount();
    require(_burnAmount > 0, "Nothing to burn...");
    
    lastBurnTime = now;

    _totalSupply = _totalSupply.sub(_burnAmount);
    balances[poolAddr] = balances[poolAddr].sub(_burnAmount);
    IUniswapV2Pair(poolAddr).sync();
    emit PoolBurn(_burnAmount);
  }

  function getBurnAmount() public view returns (uint256) {
    uint256 _time = now - lastBurnTime;
    uint256 _poolAmount = balanceOf(poolAddr);
    uint256 _burnAmount = (_poolAmount * burnRate * _time) / (day * 100);
    return _burnAmount;
  } // how much is ready to burn

  function getTotalBurned() public view returns (uint256) {
    uint256 _totalBurned = startingSupply - _totalSupply;
    return _totalBurned;
  }
// how much has been burned so far
}

library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    require(c / a == b, "SafeMath: multiplication overflow");
    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a / b;
    return c;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b <= a, "SafeMath: subtraction overflow");
    return a - b;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a, "SafeMath: addition overflow");
    return c;
  }
}

{
  "compilationTarget": {
    "UniversalProtocol.sol": "UniversalProtocol"
  },
  "evmVersion": "byzantium",
  "libraries": {},
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}