pragma solidity ^0.4.18;

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 */
contract Ownable {
  address public owner;


  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() public {
    owner = msg.sender;
  }


  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }


  /**
   * @dev Allows the current owner to transfer control of the contract to a newOwner.
   * @param newOwner The address to transfer ownership to.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
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);
}

/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    assert(c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // assert(b > 0); // Solidity automatically throws when dividing by 0
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    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) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}


/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  /**
  * @dev transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));
    require(_value <= balances[msg.sender]);

    // SafeMath.sub will throw if there is not enough balance.
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256 balance) {
    return balances[_owner];
  }

}



/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) internal allowed;


  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amount of tokens to be transferred
   */
  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    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);
    Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   *
   * Beware that changing an allowance with this method brings the risk that someone may use both the old
   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(address _owner, address _spender) public view returns (uint256) {
    return allowed[_owner][_spender];
  }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   *
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  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);
    }
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

/**
 * @title Mintable token
 * @dev Simple ERC20 Token example, with mintable token creation
 * @dev Issue: * https://github.com/OpenZeppelin/zeppelin-solidity/issues/120
 * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
 */

contract MintableToken is StandardToken, Ownable {
  event Mint(address indexed to, uint256 amount);
  event MintFinished();

  bool public mintingFinished = false;


  modifier canMint() {
    require(!mintingFinished);
    _;
  }

  /**
   * @dev Function to mint tokens
   * @param _to The address that will receive the minted tokens.
   * @param _amount The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(address _to, uint256 _amount) onlyOwner canMint public returns (bool) {
    totalSupply = totalSupply.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    Mint(_to, _amount);
    Transfer(address(0), _to, _amount);
    return true;
  }

  /**
   * @dev Function to stop minting new tokens.
   * @return True if the operation was successful.
   */
  function finishMinting() onlyOwner canMint public returns (bool) {
    mintingFinished = true;
    MintFinished();
    return true;
  }
}

contract REPOExchange is MintableToken {

  uint public deal_cancel_rate = 0;

  struct REPODeal {
    address lender;
    address borrower;

    address collateral;
    address pledge;

    uint collateralAmount;
    uint pledgeAmount;

    uint interest;
    uint lenderFee;
    uint borrowerFee;

    uint pledgeUntil;
    uint collateralUntil;
    uint endsAt;

    int state;

    /* 0 - inited
       1 - pledge payed
       2 - collateral transfered to contract and then to borrower, contract started
       3 - collateral returned to contract in time, pledge and the rest of payment went back, collateral returned, contract successfully closed

       negative codes mean negative result

       0 -> -1 pledge was not success fully payed
       0 -> -10 pledge was not success fully payed, but borrower paid in tokens

       1 -> -2 refused to provide collateral, need to return pledge and payment
       1 -> -20 refused to provide collateral, need to return pledge and payment, collateralter paid in tokens

       2 -> -3 collateral was not returned in time, pledge and payment transfered to collateralter
    */

  }

  event NewDeal(uint dealID, address lender, address borrower, address collateral, address pledge, uint collateralAmount, uint pledgeAmount,
       uint interest, uint lenderFee_, uint borrowerFee_, uint pledgeUntil, uint collateralUntil, uint endsAt);

  event PledgePayed(uint dealID);
  event PledgeNotPayed(uint dealID);
  event PledgePaymentCanceled(uint dealID);

  event CollateralTransfered(uint dealID);
  event CollateralNotTransfered(uint dealID);
  event CollateralTransferCanceled(uint dealID);

  event CollateralReturned(uint dealID);
  event CollateralNotReturned(uint dealID);

  event DealCancelRate(uint dealCancelRate);

  function setDealCancelRate(uint deal_cancel_rate_) public {
    require(msg.sender == owner);
    deal_cancel_rate = deal_cancel_rate_;
    DealCancelRate(deal_cancel_rate);
  }

  function getDealCancelRate() public constant returns (uint _deal_cancel_rate) {
    return deal_cancel_rate;
  }


  uint lastDealID;
  mapping (uint => REPODeal) deals;

  function REPOExchange() public {
  }

  function() public {
    revert();
  }

  function newDeal(address lender_, address borrower_, address collateral_, address pledge_, uint collateralAmount_, uint pledgeAmount_,
    uint interest_, uint lenderFee_, uint borrowerFee_, uint pledgeUntil_, uint collateralUntil_, uint endsAt_) public returns (uint dealID) {
    require(msg.sender == owner);
    dealID = lastDealID++;
    deals[dealID] = REPODeal(lender_, borrower_, collateral_, pledge_, collateralAmount_, pledgeAmount_,
      interest_, lenderFee_, borrowerFee_, pledgeUntil_, collateralUntil_, endsAt_, 0);

    NewDeal(dealID, lender_, borrower_, collateral_, pledge_, collateralAmount_, pledgeAmount_,
      interest_, lenderFee_, borrowerFee_, pledgeUntil_, collateralUntil_, endsAt_);
  }

  function payPledge(uint dealID) public payable {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 0);
    require(block.number < deal.pledgeUntil);
    require(msg.sender == deal.borrower);

    uint payment = deal.pledgeAmount + deal.borrowerFee;
    if (deal.pledge == 0) {
      require(msg.value == payment);
    } else {
      require(ERC20(deal.pledge).transferFrom(msg.sender, this, payment));
    }
    //all is ok, now contract has pledge
    deal.state = 1;
    PledgePayed(dealID);
  }

  function cancelPledgePayment(uint dealID) public {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 0);
    require(msg.sender == deal.borrower);
    require(this.transferFrom(msg.sender, owner, deal_cancel_rate));
    deal.state = -10;
    PledgePaymentCanceled(dealID);
  }

  function notifyPledgeNotPayed(uint dealID) public {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 0);
    require(block.number >= deal.pledgeUntil);
    deal.state = -1;
    PledgeNotPayed(dealID);
  }

  function transferCollateral(uint dealID) public payable {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 1);
    require(block.number < deal.collateralUntil);
    require(msg.sender == deal.lender);

    uint payment = deal.collateralAmount + deal.lenderFee;
    if (deal.collateral == 0) {
      require(msg.value == payment);
      require(deal.borrower.send(deal.collateralAmount));
      require(owner.send(deal.lenderFee));
    } else {
      require(ERC20(deal.collateral).transferFrom(msg.sender, deal.borrower, deal.collateralAmount));
      require(ERC20(deal.collateral).transferFrom(msg.sender, owner, deal.lenderFee));
    }

    sendGoods(deal.pledge, owner, deal.borrowerFee);

    deal.state = 2;
    CollateralTransfered(dealID);
  }

  function cancelCollateralTransfer(uint dealID) public {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 1);
    require(msg.sender == deal.lender);
    require(this.transferFrom(msg.sender, owner, deal_cancel_rate));

    sendGoods(deal.pledge, deal.borrower, deal.pledgeAmount + deal.borrowerFee);

    deal.state = -20;
    CollateralTransferCanceled(dealID);
  }

  function notifyCollateralNotTransfered(uint dealID) public {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 1);
    require(block.number >= deal.collateralUntil);

    sendGoods(deal.pledge, deal.borrower, deal.pledgeAmount + deal.borrowerFee);

    deal.state = -2;
    CollateralNotTransfered(dealID);
  }

  function sendGoods(address goods, address to, uint amount) private {
    if (goods == 0) {
      require(to.send(amount));
    } else {
      require(ERC20(goods).transfer(to, amount));
    }
  }

  function returnCollateral(uint dealID) public payable {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 2);
    require(block.number < deal.endsAt);
    require(msg.sender == deal.borrower);

    uint payment = deal.collateralAmount + deal.interest;
    if (deal.collateral == 0) {
      require(msg.value == payment);
      require(deal.lender.send(msg.value));
    } else {
      require(ERC20(deal.collateral).transferFrom(msg.sender, deal.lender, payment));
    }

    sendGoods(deal.pledge, deal.borrower, deal.pledgeAmount);

    deal.state = 3;
    CollateralReturned(dealID);
  }

  function notifyCollateralNotReturned(uint dealID) public {
    REPODeal storage deal = deals[dealID];
    require(deal.state == 2);
    require(block.number >= deal.endsAt);

    sendGoods(deal.pledge, deal.lender, deal.pledgeAmount);

    deal.state = -3;
    CollateralNotReturned(dealID);
  }
}