// File: @openzeppelin/contracts/GSN/Context.sol

pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol

pragma solidity ^0.6.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: contracts/Migrations.sol

pragma solidity ^0.6.0;


/**
 * @dev The Migrations contract is a standard truffle contract that keeps track of which migrations were done on the current network.
 * For fyDai, we have updated it and added functionality that enables it as well to work as a deployed contract registry.
 */
contract Migrations is Ownable() {
    event Registered(bytes32 name, address addr);
    uint public lastCompletedMigration;
    string public version;

    /// @dev Deployed contract to deployment address
    mapping(bytes32 => address) public contracts;

    /// @dev Contract name iterator
    bytes32[] public names;

    constructor (string memory version_) public {
        version = version_;
    }

    /// @dev Amount of registered contracts
    function length() external view returns (uint) {
        return names.length;
    }

    /// @dev Register a contract name and address
    function register(bytes32 name, address addr ) external onlyOwner {
        contracts[name] = addr;
        names.push(name);
        emit Registered(name, addr);
    }

    /// @dev Register the index of the last completed migration
    function setCompleted(uint completed) public onlyOwner {
        lastCompletedMigration = completed;
    }

    /// @dev Copy the index of the last completed migration to a new version of the Migrations contract
    function upgrade(address newAddress) public onlyOwner {
        Migrations upgraded = Migrations(newAddress);
        upgraded.setCompleted(lastCompletedMigration);
    }
}