pragma solidity 0.4.20;

/**
 * The Controller is used to manage whitelisting of contracts and and halt the normal use of Augur’s contracts (e.g., if there is a vulnerability found in Augur).  There is only one instance of the Controller, and it gets uploaded to the blockchain before all of the other contracts.  The `owner` attribute of the Controller is set to the address that called the constructor of the Controller.  The Augur team can then call functions from this address to interact with the Controller.
 *
 * Initially, Augur will have a “dev mode” that that can be enabled to allow Augur’s team to suicide funds, extract Ether or Tokens from a specific contract (in case funds inadvertently get sent somewhere they shouldn’t have), and update the Controller of a target contract to a new Controller.  Eventually, the plan is to remove this mode so that this functionality will no longer be available to anyone, including the Augur team.  At that point, the `owner` address will only be able to the `emergencyStop` and `release` functions.
 */

import 'IAugur.sol';
import 'IController.sol';
import 'IControlled.sol';
import 'libraries/token/ERC20Basic.sol';
import 'ITime.sol';


contract Controller is IController {
    struct ContractDetails {
        bytes32 name;
        address contractAddress;
        bytes20 commitHash;
        bytes32 bytecodeHash;
    }

    address public owner;
    mapping(address => bool) public whitelist;
    mapping(bytes32 => ContractDetails) public registry;
    bool public stopped = false;

    modifier onlyOwnerCaller {
        require(msg.sender == owner);
        _;
    }

    modifier onlyInBadTimes {
        require(stopped);
        _;
    }

    modifier onlyInGoodTimes {
        require(!stopped);
        _;
    }

    function Controller() public {
        owner = msg.sender;
        whitelist[msg.sender] = true;
    }

    /*
     * Contract Administration
     */

    function addToWhitelist(address _target) public onlyOwnerCaller returns (bool) {
        whitelist[_target] = true;
        return true;
    }

    function removeFromWhitelist(address _target) public onlyOwnerCaller returns (bool) {
        whitelist[_target] = false;
        return true;
    }

    function assertIsWhitelisted(address _target) public view returns (bool) {
        require(whitelist[_target]);
        return true;
    }

    function registerContract(bytes32 _key, address _address, bytes20 _commitHash, bytes32 _bytecodeHash) public onlyOwnerCaller returns (bool) {
        require(registry[_key].contractAddress == address(0));
        registry[_key] = ContractDetails(_key, _address, _commitHash, _bytecodeHash);
        return true;
    }

    function getContractDetails(bytes32 _key) public view returns (address, bytes20, bytes32) {
        ContractDetails storage _details = registry[_key];
        return (_details.contractAddress, _details.commitHash, _details.bytecodeHash);
    }

    function lookup(bytes32 _key) public view returns (address) {
        return registry[_key].contractAddress;
    }

    function transferOwnership(address _newOwner) public onlyOwnerCaller returns (bool) {
        owner = _newOwner;
        return true;
    }

    function emergencyStop() public onlyOwnerCaller onlyInGoodTimes returns (bool) {
        getAugur().logEscapeHatchChanged(true);
        stopped = true;
        return true;
    }

    function stopInEmergency() public view onlyInGoodTimes returns (bool) {
        return true;
    }

    function onlyInEmergency() public view onlyInBadTimes returns (bool) {
        return true;
    }

    /*
     * Helper functions
     */

    function getAugur() public view returns (IAugur) {
        return IAugur(lookup("Augur"));
    }

    function getTimestamp() public view returns (uint256) {
        return ITime(lookup("Time")).getTimestamp();
    }
}