Rental.sol

pragma solidity ^0.4.15;
import "./TwoPartyArbitrable.sol";

/** @title Rental
 *  This is a a contract for rental agreement.
 *  This can be used to rent objects or properties.
 *  Party A is the renter. Party B is the owner.
 *  Party A put a deposit. If everything goes well, it will be given back.
 *  Otherwize parties can claim an amount of damages. If they disagree, the arbitrator will have to solve this dispute.
 */
contract Rental is TwoPartyArbitrable {
    string constant RULING_OPTIONS = "Rule for party A (renter);Rule for Party B (owner)";
    uint8 constant AMOUNT_OF_CHOICES = 2; // The number of ruling options available.

    uint public amount; // Amount sent by party A.
    uint public damagesClaimedByPartyA; // The amount party A agrees to pay to compensate damages.
    uint public damagesClaimedByPartyB; // The amount party B claims to compensate damages.

    /** @dev Constructor. Choose the arbitrator. Should be called by party A (the payer).
     *  @param _arbitrator The arbitrator of the contract.
     *  @param _timeout Time after which a party automatically loose a dispute.
     *  @param _partyB The owner.
     *  @param _arbitratorExtraData Extra data for the arbitrator.
     *  @param _metaEvidence Link to meta-evidence JSON.
     */
    constructor(
        Arbitrator _arbitrator, 
        uint _timeout, 
        address _partyB, 
        bytes _arbitratorExtraData, 
        string _metaEvidence
    ) 
        public 
        TwoPartyArbitrable(_arbitrator,_timeout,_partyB,AMOUNT_OF_CHOICES,_arbitratorExtraData, _metaEvidence) 
        payable 
    {
        amount += msg.value;
    }

    /** @dev Claim an amount of damages.
     *  Must be called before the dispute is created.
     *  If the amount agreed is the same for both, pay it.
     *  @param _damages The amount asked or agreed to be paid.
     */
    function claimDamages(uint _damages) public onlyParty {
        // Make sure that parties can't change when a dispute already started.
        require(status < Status.DisputeCreated, "The dispute has already been created.");
        // Needed to avoid claiming 0 first and triggering an agreement. Use forfeitDeposit and unlockDeposit for the cases where 0 is claimed.
        require(_damages != 0, "There must be damages.");
        require(_damages <= amount, "Cannot claim more than balance."); // Make sure not to claim more than the contract has.

        if (msg.sender == partyA)
            damagesClaimedByPartyA = _damages;
        else
            damagesClaimedByPartyB = _damages;

        if (damagesClaimedByPartyA==damagesClaimedByPartyB) { // If there is an agreement.
            partyA.send((amount - damagesClaimedByPartyB) + partyAFee);
            partyB.send(damagesClaimedByPartyB + partyBFee);
            damagesClaimedByPartyA = 0;
            damagesClaimedByPartyB = 0;
            partyAFee = 0;
            partyBFee = 0;
            amount = 0;
            status = Status.Resolved;
        }
    }




    /** @dev Forfeit the deposit to party B.
     *  To be called if the good has been completely broken or that the property damages exceed the deposit.
     */
    function forfeitDeposit() public onlyPartyA {
        partyB.transfer(amount);
        amount = 0;
    }

    /** @dev Unlock party A deposit. To be called if the good or property has been returned without damages.
     */
    function unlockDeposit() public onlyPartyB {
        partyA.transfer(amount);
        amount = 0;
    }

    /** @dev Execute a ruling of a dispute. It reimburse the fee to the winning party.
     *  This need to be extended by contract inheriting from it.
     *  @param _disputeID ID of the dispute in the Arbitrator contract.
     *  @param _ruling Ruling given by the arbitrator. 1 : Rule for party A (renter). 2 : Rule for Party B (owner).
     */
    function executeRuling(uint _disputeID, uint _ruling) internal {
        super.executeRuling(_disputeID,_ruling);
        if (_ruling == PARTY_A_WINS) {
            partyA.send(amount - damagesClaimedByPartyA);
            partyB.send(damagesClaimedByPartyA);
        }
        else if (_ruling == PARTY_B_WINS) {
            partyA.send(amount - damagesClaimedByPartyB);
            partyB.send(damagesClaimedByPartyB);
        }

        amount = 0;
        damagesClaimedByPartyA = 0;
        damagesClaimedByPartyB = 0;
    }

}