pragma solidity ^0.5.0;

// NOTE:
// The architecture of all proxies and the ProxyFactory-contract
// has been modelled upon this blogpost by Alan Lu:
// https://blog.gnosis.pm/solidity-delegateproxy-contracts-e09957d0f201

import "./Assessment.sol";
import "./Concept.sol";
import "./AssessmentProxy.sol";
import "./ConceptProxy.sol";


/**
   @dev Factory for assessment- and concept-proxy contracts.
*/
contract ProxyFactory {
    // Proxied address for concepts, used by Proxy.sol-constructor to generate
    // storage layout
    address public masterConceptCopy;

    // Proxied address for assessments
    address public masterAssessmentCopy;

    address public owner;

    // Period of time before which proposed changes take effect, so that
    // disagreeing members to fork the network
    uint public timelimit = 7 days;

    // Proposed changes
    address public proposedMasterAssessment;
    address public proposedOwner;
    uint public proposedTimelimit;

    // Date the proposal has been submitted
    uint public proposalDate;

    event ProposedChange (
        address proposedMasterAssessment,
        address proposedOwner,
        uint proposedTimelimit
    );

    event ChangeImplemented (
        address proposedMasterAssessment,
        address proposedOwner,
        uint proposedTimelimit
    );

    /**
       @dev Save address of masterCopies for concept and assessment proxies
    */
    constructor(address _masterConcept, address _masterAssessment) public {
        owner = msg.sender;
        masterConceptCopy = _masterConcept;
        masterAssessmentCopy = _masterAssessment;
    }

    function proposeChange(
        address _proposedMasterAssessment,
        address _proposedOwner,
        uint _proposedTimelimit
    )
        public
    {
        require(msg.sender == owner, "Owner access only");
        require(isContract(_proposedMasterAssessment), "New assessment-address must be a contract");

        proposedMasterAssessment = _proposedMasterAssessment;
        proposedOwner = _proposedOwner;
        proposedTimelimit = _proposedTimelimit;
        proposalDate = now;

        emit ProposedChange(_proposedMasterAssessment, _proposedOwner, _proposedTimelimit);
    }

    function implementChange() public {
        require(msg.sender == owner, "Owner access only");
        require(now - proposalDate > timelimit, "TimeLimit must pass before change can be implemented");

        masterAssessmentCopy = proposedMasterAssessment;
        owner = proposedOwner;
        timelimit = proposedTimelimit;
        // REFACTOR could cleanup the proposed* storage variables

        emit ChangeImplemented(proposedMasterAssessment, proposedOwner, proposedTimelimit);
    }

    /**
       @notice Called by concept-contracts to create an assessment in them
    */
    function createAssessment(address _assessee, uint _cost, uint _size, uint _waitTime, uint _timeLimit)
        public
        returns (address)
    {
        return address(new AssessmentProxy(
            masterAssessmentCopy,
            msg.sender,
            _assessee,
            _cost,
            _size,
            _waitTime,
            _timeLimit
        ));
    }

    /**
       @notice Called by the conceptRegistry-contract to create new concepts under it
    */
    function createConcept(
        address[] memory _parents,
        uint[] memory _parentFactors,
        uint _lifetime,
        bytes memory _data,
        address _owner,
        address _cloneOf
    )
        public
        returns (address)
    {
        return address(new ConceptProxy(
            masterConceptCopy,
            msg.sender,
            _parents,
            _parentFactors,
            _lifetime,
            _data,
            _owner,
            _cloneOf
        ));
    }

    /**
        @return bool signalling if address is a contract
    */
    /* solhint-disable no-inline-assembly */
    function isContract(address _addr) private view returns (bool) {
        uint32 size;
        assembly {
        size := extcodesize(_addr)
                }
        return (size > 0);
    }
    /* solhint-enable no-inline-assembly */
}