contract bgVault  {
  using SafeERC20 for IERC20;
  using Address for address;
  using SafeMath for uint256;

  IERC20 public token;
  IERC20 public YFToken; // YF合约地址
  
  uint public min = 9500;
  uint public constant max = 10000;

  uint public earnLowerlimit; //池内空余资金到这个值就自动earn
  
  address public governance;
  address public controller;

  struct Player {
        uint256 stake;     // 质押总数
        uint256 payout;    // 支出
        uint256 total_out; // 已经领取的分红
  }
  mapping(address => Player) public player_; // (player => data) player data

  struct Global {
        uint256 total_stake;        // 总质押总数
        uint256 total_out;          // 总分红金额
        uint256 earnings_per_share; // 每股分红
  }
  mapping(uint256 => Global) public global_; // (global => data) global data
  mapping (address => uint256) public deposittime;
  uint256 constant internal magnitude = 10**40; // 10的40次方

  address constant public yf = address(0x96F9632b25f874769969ff91219fCCb6ceDf26D2);

  string public getName;

  constructor (address _token, uint256 _earnLowerlimit) public {
      token = IERC20(_token);
      getName = string(abi.encodePacked("yf:Vault:", ERC20Detailed(_token).name()));

      earnLowerlimit = _earnLowerlimit*1e18;
      YFToken = IERC20(yf);
      governance = tx.origin;
      controller = 0xcC8d36211374a08fC61d74ed2E48e22b922C9D7C;
  }
  
  function balance() public view returns (uint) {
      return token.balanceOf(address(this))
             .add(Controller(controller).balanceOf(address(token)));
  }
  
  function setMin(uint _min) external {
      require(msg.sender == governance, "!governance");
      min = _min;
  }

  // 设置治理地址，必须验证原来治理地址的签名
  function setGovernance(address _governance) public {
      require(msg.sender == governance, "!governance");
      governance = _governance;
  }

  // 设置控制器地址，必须验证治理地址的签名
  function setController(address _controller) public {
      require(msg.sender == governance, "!governance");
      controller = _controller;
  }

  function setEarnLowerlimit(uint256 _earnLowerlimit) public{
      require(msg.sender == governance, "!governance");
      earnLowerlimit = _earnLowerlimit;
  }

  // Custom logic in here for how much the vault allows to be borrowed
  // Sets minimum required on-hand to keep small withdrawals cheap
  // 设置多少保险库允许被借
  // 设置所需的最低限度，以保持低成本的小额取款
  function available() public view returns (uint) {
      return token.balanceOf(address(this)).mul(min).div(max); // balance*min/max 保证在合约中一直有离散的代币供用户使用
  }

  // 抵押代币给Strategy合约进行理财，代币路径如下 vault->controller->strategy
  function earn() public {
      uint _bal = available(); // 获取最小需要转给机枪池进行获取收益的代币个数
      token.safeTransfer(controller, _bal); // 转账给控制合约
      Controller(controller).earn(address(token), _bal); // 抵押代币给Strategy合约进行理财
  }

  // 存款 可以追加存款
  function deposit(uint amount) external {
      // 从用户地址中进行扣款，所以需要先进行appove对用户账户中的资金进行授权
      token.safeTransferFrom(msg.sender, address(this), amount);
      // 增加该用户的存款总数
      player_[msg.sender].stake = player_[msg.sender].stake.add(amount);
      // 如果每股分红为0
      if (global_[0].earnings_per_share != 0) {
          player_[msg.sender].payout = player_[msg.sender].payout.add(
              global_[0].earnings_per_share.mul(amount).sub(1).div(magnitude).add(1) // (((earnings_per_share*amount)-1)/magnitude)+1
          );
      }
      // 增加全局已抵押的总量
      global_[0].total_stake = global_[0].total_stake.add(amount);
      // 如果当前池子合约中已经抵押的数量大于自动赚取收益的值时，自动将合约中的代币去第三方平台抵押
      if (token.balanceOf(address(this)) > earnLowerlimit){
          earn();
      }
      // 更新用户抵押时间
      deposittime[msg.sender] = now;
  }

  // No rebalance implementation for lower fees and faster swaps
  // 取款
  function withdraw(uint amount) external {
      claim(); // 首先获取当前未领取的收益
      require(amount <= player_[msg.sender].stake, "!balance");
      uint r = amount;

      // Check balance
      uint b = token.balanceOf(address(this));
      if (b < r) { // 如果vault合约中代币余额小于用户取款的余额，则需要去Strategy合约取款获得对应的代币
          uint _withdraw = r.sub(b);
          Controller(controller).withdraw(address(token), _withdraw); // 取款
          uint _after = token.balanceOf(address(this));
          uint _diff = _after.sub(b);
          if (_diff < _withdraw) { // 策略器有可能会返回的代币变多，所以需要更新vault合约中的余额
              r = b.add(_diff);
          }
      }
      // 更新用户的已提取余额并且更新全局的每股收益
      player_[msg.sender].payout = player_[msg.sender].payout.sub(
            global_[0].earnings_per_share.mul(amount).div(magnitude)
      );
      // 更新全局存款量和用户存款量
      player_[msg.sender].stake = player_[msg.sender].stake.sub(amount);
      global_[0].total_stake = global_[0].total_stake.sub(amount);
      // 转账给用户取款的代币
      token.safeTransfer(msg.sender, r);
  }

  // Strategy.harvest 触发分红（）
  function make_profit(uint256 amount) public {
      require(amount > 0, "not 0");
      YFToken.safeTransferFrom(msg.sender, address(this), amount); // 挖矿收益存入当前合约（已扣除10%的手续费，90%的利润存进来）
      global_[0].earnings_per_share = global_[0].earnings_per_share.add(
          amount.mul(magnitude).div(global_[0].total_stake)
      );
      global_[0].total_out = global_[0].total_out.add(amount);
  }

  // 用户可领取的分红
  function cal_out(address user) public view returns (uint256) {
      uint256 _cal = global_[0].earnings_per_share.mul(player_[user].stake).div(magnitude);
      if (_cal < player_[user].payout) {
          return 0;
      } else {
          return _cal.sub(player_[user].payout);
      }
  }

  // 某个用户在路上的分红（也就是分红还没有从挖矿合约领取.只能看到，无法领取，等harvest触发后就可以领取了）
  function cal_out_pending(uint256 _pendingBalance,address user) public view returns (uint256) {
      uint256 _earnings_per_share = global_[0].earnings_per_share.add(
          _pendingBalance.mul(magnitude).div(global_[0].total_stake)
      );
      uint256 _cal = _earnings_per_share.mul(player_[user].stake).div(magnitude);
      _cal = _cal.sub(cal_out(user));
      if (_cal < player_[user].payout) {
          return 0;
      } else {
          return _cal.sub(player_[user].payout);
      }
  }

  // 用户领取分红
  function claim() public {
      uint256 out = cal_out(msg.sender);
      player_[msg.sender].payout = global_[0].earnings_per_share.mul(player_[msg.sender].stake).div(magnitude);
      player_[msg.sender].total_out = player_[msg.sender].total_out.add(out);

      if (out > 0) {
          uint256 _depositTime = now - deposittime[msg.sender];
          if (_depositTime < 1 days){ // deposit in 24h
              uint256 actually_out = _depositTime.mul(out).mul(1e18).div(1 days).div(1e18);
              uint256 to_team = out.sub(actually_out);
              YFToken.safeTransfer(Controller(controller).rewards(), to_team);
              out = actually_out;
          }
          YFToken.safeTransfer(msg.sender, out);
      }
  }
}
// vault的作用是 用户充值、提现、领取奖励
// abi文件参考: https://github.com/ystar-foundation/YstarFarming/blob/master/bgVault/abi/vault.json
function cal_out_pending(uint256 _pendingBalance,address user) public view returns (uint256) {
    uint256 _earnings_per_share = global_[0].earnings_per_share.add(
        _pendingBalance.mul(magnitude).div(global_[0].total_stake)
    );
    uint256 _cal = _earnings_per_share.mul(player_[user].stake).div(magnitude);
    _cal = _cal.sub(cal_out(user));
    if (_cal < player_[user].payout) {
        return 0;
    } else {
        return _cal.sub(player_[user].payout);
    }
}

// 某个用户在路上的分红（也就是分红还没有从挖矿合约领取.只能看到，无法领取，等harvest触发后就可以领取了）