pragma solidity ^0.4.24;

// File: node_modules/zos-lib/contracts/upgradeability/Proxy.sol

/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
  function () payable external {
    _fallback();
  }

  /**
   * @return The Address of the implementation.
   */
  function _implementation() internal view returns (address);

  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    assembly {
      // Copy msg.data. We take full control of memory in this inline assembly
      // block because it will not return to Solidity code. We overwrite the
      // Solidity scratch pad at memory position 0.
      calldatacopy(0, 0, calldatasize)

      // Call the implementation.
      // out and outsize are 0 because we don't know the size yet.
      let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)

      // Copy the returned data.
      returndatacopy(0, 0, returndatasize)

      switch result
      // delegatecall returns 0 on error.
      case 0 { revert(0, returndatasize) }
      default { return(0, returndatasize) }
    }
  }

  /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
  function _willFallback() internal {
  }

  /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
  function _fallback() internal {
    _willFallback();
    _delegate(_implementation());
  }
}

// File: openzeppelin-solidity/contracts/AddressUtils.sol

/**
 * Utility library of inline functions on addresses
 */
library AddressUtils {

  /**
   * Returns whether the target address is a contract
   * @dev This function will return false if invoked during the constructor of a contract,
   * as the code is not actually created until after the constructor finishes.
   * @param _addr address to check
   * @return whether the target address is a contract
   */
  function isContract(address _addr) internal view returns (bool) {
    uint256 size;
    // XXX Currently there is no better way to check if there is a contract in an address
    // than to check the size of the code at that address.
    // See https://ethereum.stackexchange.com/a/14016/36603
    // for more details about how this works.
    // TODO Check this again before the Serenity release, because all addresses will be
    // contracts then.
    // solium-disable-next-line security/no-inline-assembly
    assembly { size := extcodesize(_addr) }
    return size > 0;
  }

}

// File: node_modules/zos-lib/contracts/upgradeability/UpgradeabilityProxy.sol

/**
 * @title UpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract UpgradeabilityProxy is Proxy {
  /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
  event Upgraded(address implementation);

  /**
   * @dev Storage slot with the address of the current implementation.
   * This is the keccak-256 hash of "org.zeppelinos.proxy.implementation", and is
   * validated in the constructor.
   */
  bytes32 private constant IMPLEMENTATION_SLOT = 0x7050c9e0f4ca769c69bd3a8ef740bc37934f8e2c036e5a723fd8ee048ed3f8c3;

  /**
   * @dev Contract constructor.
   * @param _implementation Address of the initial implementation.
   */
  constructor(address _implementation) public {
    assert(IMPLEMENTATION_SLOT == keccak256("org.zeppelinos.proxy.implementation"));

    _setImplementation(_implementation);
  }

  /**
   * @dev Returns the current implementation.
   * @return Address of the current implementation
   */
  function _implementation() internal view returns (address impl) {
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      impl := sload(slot)
    }
  }

  /**
   * @dev Upgrades the proxy to a new implementation.
   * @param newImplementation Address of the new implementation.
   */
  function _upgradeTo(address newImplementation) internal {
    _setImplementation(newImplementation);
    emit Upgraded(newImplementation);
  }

  /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
  function _setImplementation(address newImplementation) private {
    require(AddressUtils.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");

    bytes32 slot = IMPLEMENTATION_SLOT;

    assembly {
      sstore(slot, newImplementation)
    }
  }
}

// File: node_modules/zos-lib/contracts/upgradeability/AdminUpgradeabilityProxy.sol

/**
 * @title AdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract AdminUpgradeabilityProxy is UpgradeabilityProxy {
  /**
   * @dev Emitted when the administration has been transferred.
   * @param previousAdmin Address of the previous admin.
   * @param newAdmin Address of the new admin.
   */
  event AdminChanged(address previousAdmin, address newAdmin);

  /**
   * @dev Storage slot with the admin of the contract.
   * This is the keccak-256 hash of "org.zeppelinos.proxy.admin", and is
   * validated in the constructor.
   */
  bytes32 private constant ADMIN_SLOT = 0x10d6a54a4754c8869d6886b5f5d7fbfa5b4522237ea5c60d11bc4e7a1ff9390b;

  /**
   * @dev Modifier to check whether the `msg.sender` is the admin.
   * If it is, it will run the function. Otherwise, it will delegate the call
   * to the implementation.
   */
  modifier ifAdmin() {
    if (msg.sender == _admin()) {
      _;
    } else {
      _fallback();
    }
  }

  /**
   * Contract constructor.
   * It sets the `msg.sender` as the proxy administrator.
   * @param _implementation address of the initial implementation.
   */
  constructor(address _implementation) UpgradeabilityProxy(_implementation) public {
    assert(ADMIN_SLOT == keccak256("org.zeppelinos.proxy.admin"));

    _setAdmin(msg.sender);
  }

  /**
   * @return The address of the proxy admin.
   */
  function admin() external view ifAdmin returns (address) {
    return _admin();
  }

  /**
   * @return The address of the implementation.
   */
  function implementation() external view ifAdmin returns (address) {
    return _implementation();
  }

  /**
   * @dev Changes the admin of the proxy.
   * Only the current admin can call this function.
   * @param newAdmin Address to transfer proxy administration to.
   */
  function changeAdmin(address newAdmin) external ifAdmin {
    require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
    emit AdminChanged(_admin(), newAdmin);
    _setAdmin(newAdmin);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy.
   * Only the admin can call this function.
   * @param newImplementation Address of the new implementation.
   */
  function upgradeTo(address newImplementation) external ifAdmin {
    _upgradeTo(newImplementation);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy and call a function
   * on the new implementation.
   * This is useful to initialize the proxied contract.
   * @param newImplementation Address of the new implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be
   * called, as described in
   * https://solidity.readthedocs.io/en/develop/abi-spec.html#function-selector-and-argument-encoding.
   */
  function upgradeToAndCall(address newImplementation, bytes data) payable external ifAdmin {
    _upgradeTo(newImplementation);
    require(address(this).call.value(msg.value)(data));
  }

  /**
   * @return The admin slot.
   */
  function _admin() internal view returns (address adm) {
    bytes32 slot = ADMIN_SLOT;
    assembly {
      adm := sload(slot)
    }
  }

  /**
   * @dev Sets the address of the proxy admin.
   * @param newAdmin Address of the new proxy admin.
   */
  function _setAdmin(address newAdmin) internal {
    bytes32 slot = ADMIN_SLOT;

    assembly {
      sstore(slot, newAdmin)
    }
  }

  /**
   * @dev Only fall back when the sender is not the admin.
   */
  function _willFallback() internal {
    require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
    super._willFallback();
  }
}

pragma solidity ^0.4.24;
// File: openzeppelin-zos/contracts/introspection/ERC165.sol
/**
 * @title ERC165
 * @dev https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md
 */
interface ERC165 {
  /**
   * @notice Query if a contract implements an interface
   * @param _interfaceId The interface identifier, as specified in ERC-165
   * @dev Interface identification is specified in ERC-165. This function
   * uses less than 30,000 gas.
   */
  function supportsInterface(bytes4 _interfaceId)
    external
    view
    returns (bool);
}
// File: openzeppelin-zos/contracts/token/ERC721/ERC721Basic.sol
/**
 * @title ERC721 Non-Fungible Token Standard basic interface
 * @dev see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
 */
contract ERC721Basic is ERC165 {
  event Transfer(
    address indexed _from,
    address indexed _to,
    uint256 indexed _tokenId
  );
  event Approval(
    address indexed _owner,
    address indexed _approved,
    uint256 indexed _tokenId
  );
  event ApprovalForAll(
    address indexed _owner,
    address indexed _operator,
    bool _approved
  );
  function balanceOf(address _owner) public view returns (uint256 _balance);
  function ownerOf(uint256 _tokenId) public view returns (address _owner);
  function exists(uint256 _tokenId) public view returns (bool _exists);
  function approve(address _to, uint256 _tokenId) public;
  function getApproved(uint256 _tokenId)
    public view returns (address _operator);
  function setApprovalForAll(address _operator, bool _approved) public;
  function isApprovedForAll(address _owner, address _operator)
    public view returns (bool);
  function transferFrom(address _from, address _to, uint256 _tokenId) public;
  function safeTransferFrom(address _from, address _to, uint256 _tokenId)
    public;
  function safeTransferFrom(
    address _from,
    address _to,
    uint256 _tokenId,
    bytes _data
  )
    public;
}
// File: openzeppelin-zos/contracts/token/ERC721/ERC721.sol
/**
 * @title ERC-721 Non-Fungible Token Standard, optional enumeration extension
 * @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
 */
contract ERC721Enumerable is ERC721Basic {
  function totalSupply() public view returns (uint256);
  function tokenOfOwnerByIndex(
    address _owner,
    uint256 _index
  )
    public
    view
    returns (uint256 _tokenId);
  function tokenByIndex(uint256 _index) public view returns (uint256);
}
/**
 * @title ERC-721 Non-Fungible Token Standard, optional metadata extension
 * @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
 */
contract ERC721Metadata is ERC721Basic {
  function name() external view returns (string _name);
  function symbol() external view returns (string _symbol);
  function tokenURI(uint256 _tokenId) public view returns (string);
}
/**
 * @title ERC-721 Non-Fungible Token Standard, full implementation interface
 * @dev See https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
 */
contract ERC721 is ERC721Basic, ERC721Enumerable, ERC721Metadata {
}
// File: openzeppelin-zos/contracts/token/ERC721/ERC721Receiver.sol
/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
contract ERC721Receiver {
  /**
   * @dev Magic value to be returned upon successful reception of an NFT
   *  Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`,
   *  which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
   */
  bytes4 internal constant ERC721_RECEIVED = 0x150b7a02;
  /**
   * @notice Handle the receipt of an NFT
   * @dev The ERC721 smart contract calls this function on the recipient
   * after a `safetransfer`. This function MAY throw to revert and reject the
   * transfer. Return of other than the magic value MUST result in the 
   * transaction being reverted.
   * Note: the contract address is always the message sender.
   * @param _operator The address which called `safeTransferFrom` function
   * @param _from The address which previously owned the token
   * @param _tokenId The NFT identifier which is being transfered
   * @param _data Additional data with no specified format
   * @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
   */
  function onERC721Received(
    address _operator,
    address _from,
    uint256 _tokenId,
    bytes _data
  )
    public
    returns(bytes4);
}
// File: openzeppelin-zos/contracts/math/SafeMath.sol
/**
 * @title SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  /**
  * @dev Multiplies two numbers, throws on overflow.
  */
  function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
    if (a == 0) {
      return 0;
    }
    c = a * b;
    assert(c / a == b);
    return c;
  }
  /**
  * @dev Integer division of two numbers, truncating the quotient.
  */
  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 a / b;
  }
  /**
  * @dev Subtracts two numbers, throws on overflow (i.e. if subtrahend is greater than minuend).
  */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }
  /**
  * @dev Adds two numbers, throws on overflow.
  */
  function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
    c = a + b;
    assert(c >= a);
    return c;
  }
}
// File: openzeppelin-zos/contracts/AddressUtils.sol
/**
 * Utility library of inline functions on addresses
 */
library AddressUtils {
  /**
   * Returns whether the target address is a contract
   * @dev This function will return false if invoked during the constructor of a contract,
   *  as the code is not actually created until after the constructor finishes.
   * @param addr address to check
   * @return whether the target address is a contract
   */
  function isContract(address addr) internal view returns (bool) {
    uint256 size;
    // XXX Currently there is no better way to check if there is a contract in an address
    // than to check the size of the code at that address.
    // See https://ethereum.stackexchange.com/a/14016/36603
    // for more details about how this works.
    // TODO Check this again before the Serenity release, because all addresses will be
    // contracts then.
    assembly { size := extcodesize(addr) }  // solium-disable-line security/no-inline-assembly
    return size > 0;
  }
}
// File: openzeppelin-zos/contracts/introspection/ERC165Support.sol
/**
 * @title ERC165Support
 * @dev Implements ERC165 returning true for ERC165 interface identifier
 */
contract ERC165Support is ERC165 {
  bytes4 internal constant InterfaceId_ERC165 = 0x01ffc9a7;
  /**
   * 0x01ffc9a7 ===
   *   bytes4(keccak256('supportsInterface(bytes4)'))
   */
  function supportsInterface(bytes4 _interfaceId)
    external
    view
    returns (bool) 
  {
    return _supportsInterface(_interfaceId);
  }
  function _supportsInterface(bytes4 _interfaceId)
    internal
    view
    returns (bool) 
  {
    return _interfaceId == InterfaceId_ERC165;
  }
}
// File: openzeppelin-zos/contracts/token/ERC721/ERC721BasicToken.sol
/**
 * @title ERC721 Non-Fungible Token Standard basic implementation
 * @dev see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
 */
contract ERC721BasicToken is ERC165Support, ERC721Basic {
  bytes4 private constant InterfaceId_ERC721 = 0x80ac58cd;
  /*
   * 0x80ac58cd ===
   *   bytes4(keccak256('balanceOf(address)')) ^
   *   bytes4(keccak256('ownerOf(uint256)')) ^
   *   bytes4(keccak256('approve(address,uint256)')) ^
   *   bytes4(keccak256('getApproved(uint256)')) ^
   *   bytes4(keccak256('setApprovalForAll(address,bool)')) ^
   *   bytes4(keccak256('isApprovedForAll(address,address)')) ^
   *   bytes4(keccak256('transferFrom(address,address,uint256)')) ^
   *   bytes4(keccak256('safeTransferFrom(address,address,uint256)')) ^
   *   bytes4(keccak256('safeTransferFrom(address,address,uint256,bytes)'))
   */
  bytes4 private constant InterfaceId_ERC721Exists = 0x4f558e79;
  /*
   * 0x4f558e79 ===
   *   bytes4(keccak256('exists(uint256)'))
   */
  using SafeMath for uint256;
  using AddressUtils for address;
  // Equals to `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
  // which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
  bytes4 private constant ERC721_RECEIVED = 0x150b7a02;
  // Mapping from token ID to owner
  mapping (uint256 => address) internal tokenOwner;
  // Mapping from token ID to approved address
  mapping (uint256 => address) internal tokenApprovals;
  // Mapping from owner to number of owned token
  mapping (address => uint256) internal ownedTokensCount;
  // Mapping from owner to operator approvals
  mapping (address => mapping (address => bool)) internal operatorApprovals;
  /**
   * @dev Guarantees msg.sender is owner of the given token
   * @param _tokenId uint256 ID of the token to validate its ownership belongs to msg.sender
   */
  modifier onlyOwnerOf(uint256 _tokenId) {
    require(ownerOf(_tokenId) == msg.sender);
    _;
  }
  /**
   * @dev Checks msg.sender can transfer a token, by being owner, approved, or operator
   * @param _tokenId uint256 ID of the token to validate
   */
  modifier canTransfer(uint256 _tokenId) {
    require(isApprovedOrOwner(msg.sender, _tokenId));
    _;
  }
  function _supportsInterface(bytes4 _interfaceId)
    internal
    view
    returns (bool)
  {
    return super._supportsInterface(_interfaceId) || 
      _interfaceId == InterfaceId_ERC721 || _interfaceId == InterfaceId_ERC721Exists;
  }
  /**
   * @dev Gets the balance of the specified address
   * @param _owner address to query the balance of
   * @return uint256 representing the amount owned by the passed address
   */
  function balanceOf(address _owner) public view returns (uint256) {
    require(_owner != address(0));
    return ownedTokensCount[_owner];
  }
  /**
   * @dev Gets the owner of the specified token ID
   * @param _tokenId uint256 ID of the token to query the owner of
   * @return owner address currently marked as the owner of the given token ID
   */
  function ownerOf(uint256 _tokenId) public view returns (address) {
    address owner = tokenOwner[_tokenId];
    require(owner != address(0));
    return owner;
  }
  /**
   * @dev Returns whether the specified token exists
   * @param _tokenId uint256 ID of the token to query the existence of
   * @return whether the token exists
   */
  function exists(uint256 _tokenId) public view returns (bool) {
    address owner = tokenOwner[_tokenId];
    return owner != address(0);
  }
  /**
   * @dev Approves another address to transfer the given token ID
   * The zero address indicates there is no approved address.
   * There can only be one approved address per token at a given time.
   * Can only be called by the token owner or an approved operator.
   * @param _to address to be approved for the given token ID
   * @param _tokenId uint256 ID of the token to be approved
   */
  function approve(address _to, uint256 _tokenId) public {
    address owner = ownerOf(_tokenId);
    require(_to != owner);
    require(msg.sender == owner || isApprovedForAll(owner, msg.sender));
    tokenApprovals[_tokenId] = _to;
    emit Approval(owner, _to, _tokenId);
  }
  /**
   * @dev Gets the approved address for a token ID, or zero if no address set
   * @param _tokenId uint256 ID of the token to query the approval of
   * @return address currently approved for the given token ID
   */
  function getApproved(uint256 _tokenId) public view returns (address) {
    return tokenApprovals[_tokenId];
  }
  /**
   * @dev Sets or unsets the approval of a given operator
   * An operator is allowed to transfer all tokens of the sender on their behalf
   * @param _to operator address to set the approval
   * @param _approved representing the status of the approval to be set
   */
  function setApprovalForAll(address _to, bool _approved) public {
    require(_to != msg.sender);
    operatorApprovals[msg.sender][_to] = _approved;
    emit ApprovalForAll(msg.sender, _to, _approved);
  }
  /**
   * @dev Tells whether an operator is approved by a given owner
   * @param _owner owner address which you want to query the approval of
   * @param _operator operator address which you want to query the approval of
   * @return bool whether the given operator is approved by the given owner
   */
  function isApprovedForAll(
    address _owner,
    address _operator
  )
    public
    view
    returns (bool)
  {
    return operatorApprovals[_owner][_operator];
  }
  /**
   * @dev Transfers the ownership of a given token ID to another address
   * Usage of this method is discouraged, use `safeTransferFrom` whenever possible
   * Requires the msg sender to be the owner, approved, or operator
   * @param _from current owner of the token
   * @param _to address to receive the ownership of the given token ID
   * @param _tokenId uint256 ID of the token to be transferred
  */
  function transferFrom(
    address _from,
    address _to,
    uint256 _tokenId
  )
    public
    canTransfer(_tokenId)
  {
    require(_from != address(0));
    require(_to != address(0));
    clearApproval(_from, _tokenId);
    removeTokenFrom(_from, _tokenId);
    addTokenTo(_to, _tokenId);
    emit Transfer(_from, _to, _tokenId);
  }
  /**
   * @dev Safely transfers the ownership of a given token ID to another address
   * If the target address is a contract, it must implement `onERC721Received`,
   * which is called upon a safe transfer, and return the magic value
   * `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`; otherwise,
   * the transfer is reverted.
   *
   * Requires the msg sender to be the owner, approved, or operator
   * @param _from current owner of the token
   * @param _to address to receive the ownership of the given token ID
   * @param _tokenId uint256 ID of the token to be transferred
  */
  function safeTransferFrom(
    address _from,
    address _to,
    uint256 _tokenId
  )
    public
    canTransfer(_tokenId)
  {
    // solium-disable-next-line arg-overflow
    safeTransferFrom(_from, _to, _tokenId, "");
  }
  /**
   * @dev Safely transfers the ownership of a given token ID to another address
   * If the target address is a contract, it must implement `onERC721Received`,
   * which is called upon a safe transfer, and return the magic value
   * `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`; otherwise,
   * the transfer is reverted.
   * Requires the msg sender to be the owner, approved, or operator
   * @param _from current owner of the token
   * @param _to address to receive the ownership of the given token ID
   * @param _tokenId uint256 ID of the token to be transferred
   * @param _data bytes data to send along with a safe transfer check
   */
  function safeTransferFrom(
    address _from,
    address _to,
    uint256 _tokenId,
    bytes _data
  )
    public
    canTransfer(_tokenId)
  {
    transferFrom(_from, _to, _tokenId);
    // solium-disable-next-line arg-overflow
    require(checkAndCallSafeTransfer(_from, _to, _tokenId, _data));
  }
  /**
   * @dev Returns whether the given spender can transfer a given token ID
   * @param _spender address of the spender to query
   * @param _tokenId uint256 ID of the token to be transferred
   * @return bool whether the msg.sender is approved for the given token ID,
   *  is an operator of the owner, or is the owner of the token
   */
  function isApprovedOrOwner(
    address _spender,
    uint256 _tokenId
  )
    internal
    view
    returns (bool)
  {
    address owner = ownerOf(_tokenId);
    // Disable solium check because of
    // https://github.com/duaraghav8/Solium/issues/175
    // solium-disable-next-line operator-whitespace
    return (
      _spender == owner ||
      getApproved(_tokenId) == _spender ||
      isApprovedForAll(owner, _spender)
    );
  }
  /**
   * @dev Internal function to mint a new token
   * Reverts if the given token ID already exists
   * @param _to The address that will own the minted token
   * @param _tokenId uint256 ID of the token to be minted by the msg.sender
   */
  function _mint(address _to, uint256 _tokenId) internal {
    require(_to != address(0));
    addTokenTo(_to, _tokenId);
    emit Transfer(address(0), _to, _tokenId);
  }
  /**
   * @dev Internal function to burn a specific token
   * Reverts if the token does not exist
   * @param _tokenId uint256 ID of the token being burned by the msg.sender
   */
  function _burn(address _owner, uint256 _tokenId) internal {
    clearApproval(_owner, _tokenId);
    removeTokenFrom(_owner, _tokenId);
    emit Transfer(_owner, address(0), _tokenId);
  }
  /**
   * @dev Internal function to clear current approval of a given token ID
   * Reverts if the given address is not indeed the owner of the token
   * @param _owner owner of the token
   * @param _tokenId uint256 ID of the token to be transferred
   */
  function clearApproval(address _owner, uint256 _tokenId) internal {
    require(ownerOf(_tokenId) == _owner);
    if (tokenApprovals[_tokenId] != address(0)) {
      tokenApprovals[_tokenId] = address(0);
    }
  }
  /**
   * @dev Internal function to add a token ID to the list of a given address
   * @param _to address representing the new owner of the given token ID
   * @param _tokenId uint256 ID of the token to be added to the tokens list of the given address
   */
  function addTokenTo(address _to, uint256 _tokenId) internal {
    require(tokenOwner[_tokenId] == address(0));
    tokenOwner[_tokenId] = _to;
    ownedTokensCount[_to] = ownedTokensCount[_to].add(1);
  }
  /**
   * @dev Internal function to remove a token ID from the list of a given address
   * @param _from address representing the previous owner of the given token ID
   * @param _tokenId uint256 ID of the token to be removed from the tokens list of the given address
   */
  function removeTokenFrom(address _from, uint256 _tokenId) internal {
    require(ownerOf(_tokenId) == _from);
    ownedTokensCount[_from] = ownedTokensCount[_from].sub(1);
    tokenOwner[_tokenId] = address(0);
  }
  /**
   * @dev Internal function to invoke `onERC721Received` on a target address
   * The call is not executed if the target address is not a contract
   * @param _from address representing the previous owner of the given token ID
   * @param _to target address that will receive the tokens
   * @param _tokenId uint256 ID of the token to be transferred
   * @param _data bytes optional data to send along with the call
   * @return whether the call correctly returned the expected magic value
   */
  function checkAndCallSafeTransfer(
    address _from,
    address _to,
    uint256 _tokenId,
    bytes _data
  )
    internal
    returns (bool)
  {
    if (!_to.isContract()) {
      return true;
    }
    bytes4 retval = ERC721Receiver(_to).onERC721Received(
      msg.sender, _from, _tokenId, _data);
    return (retval == ERC721_RECEIVED);
  }
}
// File: zos-lib/contracts/migrations/Migratable.sol
/**
 * @title Migratable
 * Helper contract to support intialization and migration schemes between
 * different implementations of a contract in the context of upgradeability.
 * To use it, replace the constructor with a function that has the
 * `isInitializer` modifier starting with `"0"` as `migrationId`.
 * When you want to apply some migration code during an upgrade, increase
 * the `migrationId`. Or, if the migration code must be applied only after
 * another migration has been already applied, use the `isMigration` modifier.
 * This helper supports multiple inheritance.
 * WARNING: It is the developer's responsibility to ensure that migrations are
 * applied in a correct order, or that they are run at all.
 * See `Initializable` for a simpler version.
 */
contract Migratable {
  /**
   * @dev Emitted when the contract applies a migration.
   * @param contractName Name of the Contract.
   * @param migrationId Identifier of the migration applied.
   */
  event Migrated(string contractName, string migrationId);
  /**
   * @dev Mapping of the already applied migrations.
   * (contractName => (migrationId => bool))
   */
  mapping (string => mapping (string => bool)) internal migrated;
  /**
   * @dev Internal migration id used to specify that a contract has already been initialized.
   */
  string constant private INITIALIZED_ID = "initialized";
  /**
   * @dev Modifier to use in the initialization function of a contract.
   * @param contractName Name of the contract.
   * @param migrationId Identifier of the migration.
   */
  modifier isInitializer(string contractName, string migrationId) {
    validateMigrationIsPending(contractName, INITIALIZED_ID);
    validateMigrationIsPending(contractName, migrationId);
    _;
    emit Migrated(contractName, migrationId);
    migrated[contractName][migrationId] = true;
    migrated[contractName][INITIALIZED_ID] = true;
  }
  /**
   * @dev Modifier to use in the migration of a contract.
   * @param contractName Name of the contract.
   * @param requiredMigrationId Identifier of the previous migration, required
   * to apply new one.
   * @param newMigrationId Identifier of the new migration to be applied.
   */
  modifier isMigration(string contractName, string requiredMigrationId, string newMigrationId) {
    require(isMigrated(contractName, requiredMigrationId), "Prerequisite migration ID has not been run yet");
    validateMigrationIsPending(contractName, newMigrationId);
    _;
    emit Migrated(contractName, newMigrationId);
    migrated[contractName][newMigrationId] = true;
  }
  /**
   * @dev Returns true if the contract migration was applied.
   * @param contractName Name of the contract.
   * @param migrationId Identifier of the migration.
   * @return true if the contract migration was applied, false otherwise.
   */
  function isMigrated(string contractName, string migrationId) public view returns(bool) {
    return migrated[contractName][migrationId];
  }
  /**
   * @dev Initializer that marks the contract as initialized.
   * It is important to run this if you had deployed a previous version of a Migratable contract.
   * For more information see https://github.com/zeppelinos/zos-lib/issues/158.
   */
  function initialize() isInitializer("Migratable", "1.2.1") public {
  }
  /**
   * @dev Reverts if the requested migration was already executed.
   * @param contractName Name of the contract.
   * @param migrationId Identifier of the migration.
   */
  function validateMigrationIsPending(string contractName, string migrationId) private view {
    require(!isMigrated(contractName, migrationId), "Requested target migration ID has already been run");
  }
}
// File: openzeppelin-zos/contracts/token/ERC721/ERC721Token.sol
/**
 * @title Full ERC721 Token
 * This implementation includes all the required and some optional functionality of the ERC721 standard
 * Moreover, it includes approve all functionality using operator terminology
 * @dev see https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
 */
contract ERC721Token is Migratable, ERC165Support, ERC721BasicToken, ERC721 {
  bytes4 private constant InterfaceId_ERC721Enumerable = 0x780e9d63;
  /**
   * 0x780e9d63 ===
   *   bytes4(keccak256('totalSupply()')) ^
   *   bytes4(keccak256('tokenOfOwnerByIndex(address,uint256)')) ^
   *   bytes4(keccak256('tokenByIndex(uint256)'))
   */
  bytes4 private constant InterfaceId_ERC721Metadata = 0x5b5e139f;
  /**
   * 0x5b5e139f ===
   *   bytes4(keccak256('name()')) ^
   *   bytes4(keccak256('symbol()')) ^
   *   bytes4(keccak256('tokenURI(uint256)'))
   */
  // Token name
  string internal name_;
  // Token symbol
  string internal symbol_;
  // Mapping from owner to list of owned token IDs
  mapping(address => uint256[]) internal ownedTokens;
  // Mapping from token ID to index of the owner tokens list
  mapping(uint256 => uint256) internal ownedTokensIndex;
  // Array with all token ids, used for enumeration
  uint256[] internal allTokens;
  // Mapping from token id to position in the allTokens array
  mapping(uint256 => uint256) internal allTokensIndex;
  // Optional mapping for token URIs
  mapping(uint256 => string) internal tokenURIs;
  /**
   * @dev Constructor function
   */
  function initialize(string _name, string _symbol) public isInitializer("ERC721Token", "1.9.0") {
    name_ = _name;
    symbol_ = _symbol;
  }
  function _supportsInterface(bytes4 _interfaceId)
    internal
    view
    returns (bool)
  {
    return super._supportsInterface(_interfaceId) || 
      _interfaceId == InterfaceId_ERC721Enumerable || _interfaceId == InterfaceId_ERC721Metadata;
  }
  /**
   * @dev Gets the token name
   * @return string representing the token name
   */
  function name() external view returns (string) {
    return name_;
  }
  /**
   * @dev Gets the token symbol
   * @return string representing the token symbol
   */
  function symbol() external view returns (string) {
    return symbol_;
  }
  /**
   * @dev Returns an URI for a given token ID
   * Throws if the token ID does not exist. May return an empty string.
   * @param _tokenId uint256 ID of the token to query
   */
  function tokenURI(uint256 _tokenId) public view returns (string) {
    require(exists(_tokenId));
    return tokenURIs[_tokenId];
  }
  /**
   * @dev Gets the token ID at a given index of the tokens list of the requested owner
   * @param _owner address owning the tokens list to be accessed
   * @param _index uint256 representing the index to be accessed of the requested tokens list
   * @return uint256 token ID at the given index of the tokens list owned by the requested address
   */
  function tokenOfOwnerByIndex(
    address _owner,
    uint256 _index
  )
    public
    view
    returns (uint256)
  {
    require(_index < balanceOf(_owner));
    return ownedTokens[_owner][_index];
  }
  /**
   * @dev Gets the total amount of tokens stored by the contract
   * @return uint256 representing the total amount of tokens
   */
  function totalSupply() public view returns (uint256) {
    return allTokens.length;
  }
  /**
   * @dev Gets the token ID at a given index of all the tokens in this contract
   * Reverts if the index is greater or equal to the total number of tokens
   * @param _index uint256 representing the index to be accessed of the tokens list
   * @return uint256 token ID at the given index of the tokens list
   */
  function tokenByIndex(uint256 _index) public view returns (uint256) {
    require(_index < totalSupply());
    return allTokens[_index];
  }
  /**
   * @dev Internal function to set the token URI for a given token
   * Reverts if the token ID does not exist
   * @param _tokenId uint256 ID of the token to set its URI
   * @param _uri string URI to assign
   */
  function _setTokenURI(uint256 _tokenId, string _uri) internal {
    require(exists(_tokenId));
    tokenURIs[_tokenId] = _uri;
  }
  /**
   * @dev Internal function to add a token ID to the list of a given address
   * @param _to address representing the new owner of the given token ID
   * @param _tokenId uint256 ID of the token to be added to the tokens list of the given address
   */
  function addTokenTo(address _to, uint256 _tokenId) internal {
    super.addTokenTo(_to, _tokenId);
    uint256 length = ownedTokens[_to].length;
    ownedTokens[_to].push(_tokenId);
    ownedTokensIndex[_tokenId] = length;
  }
  /**
   * @dev Internal function to remove a token ID from the list of a given address
   * @param _from address representing the previous owner of the given token ID
   * @param _tokenId uint256 ID of the token to be removed from the tokens list of the given address
   */
  function removeTokenFrom(address _from, uint256 _tokenId) internal {
    super.removeTokenFrom(_from, _tokenId);
    uint256 tokenIndex = ownedTokensIndex[_tokenId];
    uint256 lastTokenIndex = ownedTokens[_from].length.sub(1);
    uint256 lastToken = ownedTokens[_from][lastTokenIndex];
    ownedTokens[_from][tokenIndex] = lastToken;
    ownedTokens[_from][lastTokenIndex] = 0;
    // Note that this will handle single-element arrays. In that case, both tokenIndex and lastTokenIndex are going to
    // be zero. Then we can make sure that we will remove _tokenId from the ownedTokens list since we are first swapping
    // the lastToken to the first position, and then dropping the element placed in the last position of the list
    ownedTokens[_from].length--;
    ownedTokensIndex[_tokenId] = 0;
    ownedTokensIndex[lastToken] = tokenIndex;
  }
  /**
   * @dev Internal function to mint a new token
   * Reverts if the given token ID already exists
   * @param _to address the beneficiary that will own the minted token
   * @param _tokenId uint256 ID of the token to be minted by the msg.sender
   */
  function _mint(address _to, uint256 _tokenId) internal {
    super._mint(_to, _tokenId);
    allTokensIndex[_tokenId] = allTokens.length;
    allTokens.push(_tokenId);
  }
  /**
   * @dev Internal function to burn a specific token
   * Reverts if the token does not exist
   * @param _owner owner of the token to burn
   * @param _tokenId uint256 ID of the token being burned by the msg.sender
   */
  function _burn(address _owner, uint256 _tokenId) internal {
    super._burn(_owner, _tokenId);
    // Clear metadata (if any)
    if (bytes(tokenURIs[_tokenId]).length != 0) {
      delete tokenURIs[_tokenId];
    }
    // Reorg all tokens array
    uint256 tokenIndex = allTokensIndex[_tokenId];
    uint256 lastTokenIndex = allTokens.length.sub(1);
    uint256 lastToken = allTokens[lastTokenIndex];
    allTokens[tokenIndex] = lastToken;
    allTokens[lastTokenIndex] = 0;
    allTokens.length--;
    allTokensIndex[_tokenId] = 0;
    allTokensIndex[lastToken] = tokenIndex;
  }
}
// File: openzeppelin-zos/contracts/ownership/Ownable.sol
/**
 * @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 is Migratable {
  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 initialize(address _sender) public isInitializer("Ownable", "1.9.0") {
    owner = _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));
    emit OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }
}
// File: contracts/estate/IEstateRegistry.sol
contract IEstateRegistry {
  function mint(address to, string metadata) external returns (uint256);
  function ownerOf(uint256 _tokenId) public view returns (address _owner); // from ERC721
  // Events
  event CreateEstate(
    address indexed _owner,
    uint256 indexed _estateId,
    string _data
  );
  event AddLand(
    uint256 indexed _estateId,
    uint256 indexed _landId
  );
  event RemoveLand(
    uint256 indexed _estateId,
    uint256 indexed _landId,
    address indexed _destinatary
  );
  event Update(
    uint256 indexed _assetId,
    address indexed _holder,
    address indexed _operator,
    string _data
  );
  event UpdateOperator(
    uint256 indexed _estateId,
    address indexed _operator
  );
  event UpdateManager(
    address indexed _owner,
    address indexed _operator,
    address indexed _caller,
    bool _approved
  );
  event SetLANDRegistry(
    address indexed _registry
  );
  event SetEstateLandBalanceToken(
    address indexed _previousEstateLandBalance,
    address indexed _newEstateLandBalance
  );
}
// File: contracts/minimeToken/IMinimeToken.sol
interface IMiniMeToken {
////////////////
// Generate and destroy tokens
////////////////
    /// @notice Generates `_amount` tokens that are assigned to `_owner`
    /// @param _owner The address that will be assigned the new tokens
    /// @param _amount The quantity of tokens generated
    /// @return True if the tokens are generated correctly
    function generateTokens(address _owner, uint _amount) external returns (bool);
    /// @notice Burns `_amount` tokens from `_owner`
    /// @param _owner The address that will lose the tokens
    /// @param _amount The quantity of tokens to burn
    /// @return True if the tokens are burned correctly
    function destroyTokens(address _owner, uint _amount) external returns (bool);
    /// @param _owner The address that's balance is being requested
    /// @return The balance of `_owner` at the current block
    function balanceOf(address _owner) external view returns (uint256 balance);
    event Transfer(address indexed _from, address indexed _to, uint256 _amount);
}
// File: contracts/estate/EstateStorage.sol
contract LANDRegistry {
  function decodeTokenId(uint value) external pure returns (int, int);
  function updateLandData(int x, int y, string data) external;
  function setUpdateOperator(uint256 assetId, address operator) external;
  function setManyUpdateOperator(uint256[] landIds, address operator) external;
  function ping() public;
  function ownerOf(uint256 tokenId) public returns (address);
  function safeTransferFrom(address, address, uint256) public;
  function updateOperator(uint256 landId) public returns (address);
}
contract EstateStorage {
  bytes4 internal constant InterfaceId_GetMetadata = bytes4(keccak256("getMetadata(uint256)"));
  bytes4 internal constant InterfaceId_VerifyFingerprint = bytes4(
    keccak256("verifyFingerprint(uint256,bytes)")
  );
  LANDRegistry public registry;
  // From Estate to list of owned LAND ids (LANDs)
  mapping(uint256 => uint256[]) public estateLandIds;
  // From LAND id (LAND) to its owner Estate id
  mapping(uint256 => uint256) public landIdEstate;
  // From Estate id to mapping of LAND id to index on the array above (estateLandIds)
  mapping(uint256 => mapping(uint256 => uint256)) public estateLandIndex;
  // Metadata of the Estate
  mapping(uint256 => string) internal estateData;
  // Operator of the Estate
  mapping (uint256 => address) public updateOperator;
  // From account to mapping of operator to bool whether is allowed to update content or not
  mapping(address => mapping(address => bool)) public updateManager;
  // Land balance minime token
  IMiniMeToken public estateLandBalance;
  // Registered balance accounts
  mapping(address => bool) public registeredBalance;
}
// File: contracts/estate/EstateRegistry.sol
/**
 * @title ERC721 registry of every minted Estate and their owned LANDs
 * @dev Usings we are inheriting and depending on:
 * From ERC721Token:
 *   - using SafeMath for uint256;
 *   - using AddressUtils for address;
 */
// solium-disable-next-line max-len
contract EstateRegistry is Migratable, IEstateRegistry, ERC721Token, ERC721Receiver, Ownable, EstateStorage {
  modifier canTransfer(uint256 estateId) {
    require(isApprovedOrOwner(msg.sender, estateId), "Only owner or operator can transfer");
    _;
  }
  modifier onlyRegistry() {
    require(msg.sender == address(registry), "Only the registry can make this operation");
    _;
  }
  modifier onlyUpdateAuthorized(uint256 estateId) {
    require(_isUpdateAuthorized(msg.sender, estateId), "Unauthorized user");
    _;
  }
  modifier onlyLandUpdateAuthorized(uint256 estateId, uint256 landId) {
    require(_isLandUpdateAuthorized(msg.sender, estateId, landId), "unauthorized user");
    _;
  }
  modifier canSetUpdateOperator(uint256 estateId) {
    address owner = ownerOf(estateId);
    require(
      isApprovedOrOwner(msg.sender, estateId) || updateManager[owner][msg.sender],
      "unauthorized user"
    );
    _;
  }
  /**
   * @dev Mint a new Estate with some metadata
   * @param to The address that will own the minted token
   * @param metadata Set an initial metadata
   * @return An uint256 representing the new token id
   */
  function mint(address to, string metadata) external onlyRegistry returns (uint256) {
    return _mintEstate(to, metadata);
  }
  /**
   * @notice Transfer a LAND owned by an Estate to a new owner
   * @param estateId Current owner of the token
   * @param landId LAND to be transfered
   * @param destinatary New owner
   */
  function transferLand(
    uint256 estateId,
    uint256 landId,
    address destinatary
  )
    external
    canTransfer(estateId)
  {
    return _transferLand(estateId, landId, destinatary);
  }
  /**
   * @notice Transfer many tokens owned by an Estate to a new owner
   * @param estateId Current owner of the token
   * @param landIds LANDs to be transfered
   * @param destinatary New owner
   */
  function transferManyLands(
    uint256 estateId,
    uint256[] landIds,
    address destinatary
  )
    external
    canTransfer(estateId)
  {
    uint length = landIds.length;
    for (uint i = 0; i < length; i++) {
      _transferLand(estateId, landIds[i], destinatary);
    }
  }
  /**
   * @notice Get the Estate id for a given LAND id
   * @dev This information also lives on estateLandIds,
   *   but it being a mapping you need to know the Estate id beforehand.
   * @param landId LAND to search
   * @return The corresponding Estate id
   */
  function getLandEstateId(uint256 landId) external view returns (uint256) {
    return landIdEstate[landId];
  }
  function setLANDRegistry(address _registry) external onlyOwner {
    require(_registry.isContract(), "The LAND registry address should be a contract");
    require(_registry != 0, "The LAND registry address should be valid");
    registry = LANDRegistry(_registry);
    emit SetLANDRegistry(registry);
  }
  function ping() external {
    registry.ping();
  }
  /**
   * @notice Return the amount of tokens for a given Estate
   * @param estateId Estate id to search
   * @return Tokens length
   */
  function getEstateSize(uint256 estateId) external view returns (uint256) {
    return estateLandIds[estateId].length;
  }
  /**
   * @notice Return the amount of LANDs inside the Estates for a given address
   * @param _owner of the estates
   * @return the amount of LANDs
   */
  function getLANDsSize(address _owner) public view returns (uint256) {
    // Avoid balanceOf to not compute an unnecesary require
    uint256 landsSize;
    uint256 balance = ownedTokensCount[_owner];
    for (uint256 i; i < balance; i++) {
      uint256 estateId = ownedTokens[_owner][i];
      landsSize += estateLandIds[estateId].length;
    }
    return landsSize;
  }
  /**
   * @notice Update the metadata of an Estate
   * @dev Reverts if the Estate does not exist or the user is not authorized
   * @param estateId Estate id to update
   * @param metadata string metadata
   */
  function updateMetadata(
    uint256 estateId,
    string metadata
  )
    external
    onlyUpdateAuthorized(estateId)
  {
    _updateMetadata(estateId, metadata);
    emit Update(
      estateId,
      ownerOf(estateId),
      msg.sender,
      metadata
    );
  }
  function getMetadata(uint256 estateId) external view returns (string) {
    return estateData[estateId];
  }
  function isUpdateAuthorized(address operator, uint256 estateId) external view returns (bool) {
    return _isUpdateAuthorized(operator, estateId);
  }
  /**
  * @dev Set an updateManager for an account
  * @param _owner - address of the account to set the updateManager
  * @param _operator - address of the account to be set as the updateManager
  * @param _approved - bool whether the address will be approved or not
  */
  function setUpdateManager(address _owner, address _operator, bool _approved) external {
    require(_operator != msg.sender, "The operator should be different from owner");
    require(
      _owner == msg.sender
      || operatorApprovals[_owner][msg.sender],
      "Unauthorized user"
    );
    updateManager[_owner][_operator] = _approved;
    emit UpdateManager(
      _owner,
      _operator,
      msg.sender,
      _approved
    );
  }
  /**
   * @notice Set Estate updateOperator
   * @param estateId - Estate id
   * @param operator - address of the account to be set as the updateOperator
   */
  function setUpdateOperator(
    uint256 estateId,
    address operator
  )
    public
    canSetUpdateOperator(estateId)
  {
    updateOperator[estateId] = operator;
    emit UpdateOperator(estateId, operator);
  }
  /**
   * @notice Set Estates updateOperator
   * @param _estateIds - Estate ids
   * @param _operator - address of the account to be set as the updateOperator
   */
  function setManyUpdateOperator(
    uint256[] _estateIds,
    address _operator
  )
    public
  {
    for (uint i = 0; i < _estateIds.length; i++) {
      setUpdateOperator(_estateIds[i], _operator);
    }
  }
  /**
   * @notice Set LAND updateOperator
   * @param estateId - Estate id
   * @param landId - LAND to set the updateOperator
   * @param operator - address of the account to be set as the updateOperator
   */
  function setLandUpdateOperator(
    uint256 estateId,
    uint256 landId,
    address operator
  )
    public
    canSetUpdateOperator(estateId)
  {
    require(landIdEstate[landId] == estateId, "The LAND is not part of the Estate");
    registry.setUpdateOperator(landId, operator);
  }
 /**
   * @notice Set many LAND updateOperator
   * @param _estateId - Estate id
   * @param _landIds - LANDs to set the updateOperator
   * @param _operator - address of the account to be set as the updateOperator
   */
  function setManyLandUpdateOperator(
    uint256 _estateId,
    uint256[] _landIds,
    address _operator
  )
    public
    canSetUpdateOperator(_estateId)
  {
    for (uint i = 0; i < _landIds.length; i++) {
      require(landIdEstate[_landIds[i]] == _estateId, "The LAND is not part of the Estate");
    }
    registry.setManyUpdateOperator(_landIds, _operator);
  }
  function initialize(
    string _name,
    string _symbol,
    address _registry
  )
    public
    isInitializer("EstateRegistry", "0.0.2")
  {
    require(_registry != 0, "The registry should be a valid address");
    ERC721Token.initialize(_name, _symbol);
    Ownable.initialize(msg.sender);
    registry = LANDRegistry(_registry);
  }
  /**
   * @notice Handle the receipt of an NFT
   * @dev The ERC721 smart contract calls this function on the recipient
   * after a `safetransfer`. This function MAY throw to revert and reject the
   * transfer. Return of other than the magic value MUST result in the
   * transaction being reverted.
   * Note: the contract address is always the message sender.
   * @param _operator The address which called `safeTransferFrom` function
   * @param _from The address which previously owned the token
   * @param _tokenId The NFT identifier which is being transferred
   * @param _data Additional data with no specified format
   * @return `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
   */
  function onERC721Received(
    address _operator,
    address _from,
    uint256 _tokenId,
    bytes _data
  )
    public
    onlyRegistry
    returns (bytes4)
  {
    uint256 estateId = _bytesToUint(_data);
    _pushLandId(estateId, _tokenId);
    return ERC721_RECEIVED;
  }
  /**
   * @dev Creates a checksum of the contents of the Estate
   * @param estateId the estateId to be verified
   */
  function getFingerprint(uint256 estateId)
    public
    view
    returns (bytes32 result)
  {
    result = keccak256(abi.encodePacked("estateId", estateId));
    uint256 length = estateLandIds[estateId].length;
    for (uint i = 0; i < length; i++) {
      result ^= keccak256(abi.encodePacked(estateLandIds[estateId][i]));
    }
    return result;
  }
  /**
   * @dev Verifies a checksum of the contents of the Estate
   * @param estateId the estateid to be verified
   * @param fingerprint the user provided identification of the Estate contents
   */
  function verifyFingerprint(uint256 estateId, bytes fingerprint) public view returns (bool) {
    return getFingerprint(estateId) == _bytesToBytes32(fingerprint);
  }
  /**
   * @dev Safely transfers the ownership of multiple Estate IDs to another address
   * @dev Delegates to safeTransferFrom for each transfer
   * @dev Requires the msg sender to be the owner, approved, or operator
   * @param from current owner of the token
   * @param to address to receive the ownership of the given token ID
   * @param estateIds uint256 array of IDs to be transferred
  */
  function safeTransferManyFrom(address from, address to, uint256[] estateIds) public {
    safeTransferManyFrom(
      from,
      to,
      estateIds,
      ""
    );
  }
  /**
   * @dev Safely transfers the ownership of multiple Estate IDs to another address
   * @dev Delegates to safeTransferFrom for each transfer
   * @dev Requires the msg sender to be the owner, approved, or operator
   * @param from current owner of the token
   * @param to address to receive the ownership of the given token ID
   * @param estateIds uint256 array of IDs to be transferred
   * @param data bytes data to send along with a safe transfer check
  */
  function safeTransferManyFrom(
    address from,
    address to,
    uint256[] estateIds,
    bytes data
  )
    public
  {
    for (uint i = 0; i < estateIds.length; i++) {
      safeTransferFrom(
        from,
        to,
        estateIds[i],
        data
      );
    }
  }
  /**
   * @dev update LAND data owned by an Estate
   * @param estateId Estate
   * @param landId LAND to be updated
   * @param data string metadata
   */
  function updateLandData(uint256 estateId, uint256 landId, string data) public {
    _updateLandData(estateId, landId, data);
  }
  /**
   * @dev update LANDs data owned by an Estate
   * @param estateId Estate id
   * @param landIds LANDs to be updated
   * @param data string metadata
   */
  function updateManyLandData(uint256 estateId, uint256[] landIds, string data) public {
    uint length = landIds.length;
    for (uint i = 0; i < length; i++) {
      _updateLandData(estateId, landIds[i], data);
    }
  }
  function transferFrom(address _from, address _to, uint256 _tokenId)
  public
  {
    uint256 estateSize = estateLandIds[_tokenId].length;
    require(estateSize != 0, "The Estate should not be empty");
    updateOperator[_tokenId] = address(0);
    _updateEstateLandBalance(_from, _to, estateSize);
    super.transferFrom(_from, _to, _tokenId);
  }
  // check the supported interfaces via ERC165
  function _supportsInterface(bytes4 _interfaceId) internal view returns (bool) {
    // solium-disable-next-line operator-whitespace
    return super._supportsInterface(_interfaceId)
      || _interfaceId == InterfaceId_GetMetadata
      || _interfaceId == InterfaceId_VerifyFingerprint;
  }
  /**
   * @dev Internal function to mint a new Estate with some metadata
   * @param to The address that will own the minted token
   * @param metadata Set an initial metadata
   * @return An uint256 representing the new token id
   */
  function _mintEstate(address to, string metadata) internal returns (uint256) {
    require(to != address(0), "You can not mint to an empty address");
    uint256 estateId = _getNewEstateId();
    _mint(to, estateId);
    _updateMetadata(estateId, metadata);
    emit CreateEstate(to, estateId, metadata);
    return estateId;
  }
  /**
   * @dev Internal function to update an Estate metadata
   * @dev Does not require the Estate to exist, for a public interface use `updateMetadata`
   * @param estateId Estate id to update
   * @param metadata string metadata
   */
  function _updateMetadata(uint256 estateId, string metadata) internal {
    estateData[estateId] = metadata;
  }
  /**
   * @notice Return a new unique id
   * @dev It uses totalSupply to determine the next id
   * @return uint256 Representing the new Estate id
   */
  function _getNewEstateId() internal view returns (uint256) {
    return totalSupply().add(1);
  }
  /**
   * @dev Appends a new LAND id to an Estate updating all related storage
   * @param estateId Estate where the LAND should go
   * @param landId Transfered LAND
   */
  function _pushLandId(uint256 estateId, uint256 landId) internal {
    require(exists(estateId), "The Estate id should exist");
    require(landIdEstate[landId] == 0, "The LAND is already owned by an Estate");
    require(registry.ownerOf(landId) == address(this), "The EstateRegistry cannot manage the LAND");
    estateLandIds[estateId].push(landId);
    landIdEstate[landId] = estateId;
    estateLandIndex[estateId][landId] = estateLandIds[estateId].length;
    address owner = ownerOf(estateId);
    _updateEstateLandBalance(address(registry), owner, 1);
    emit AddLand(estateId, landId);
  }
  /**
   * @dev Removes a LAND from an Estate and transfers it to a new owner
   * @param estateId Current owner of the LAND
   * @param landId LAND to be transfered
   * @param destinatary New owner
   */
  function _transferLand(
    uint256 estateId,
    uint256 landId,
    address destinatary
  )
    internal
  {
    require(destinatary != address(0), "You can not transfer LAND to an empty address");
    uint256[] storage landIds = estateLandIds[estateId];
    mapping(uint256 => uint256) landIndex = estateLandIndex[estateId];
    /**
     * Using 1-based indexing to be able to make this check
     */
    require(landIndex[landId] != 0, "The LAND is not part of the Estate");
    uint lastIndexInArray = landIds.length.sub(1);
    /**
     * Get the landIndex of this token in the landIds list
     */
    uint indexInArray = landIndex[landId].sub(1);
    /**
     * Get the landId at the end of the landIds list
     */
    uint tempTokenId = landIds[lastIndexInArray];
    /**
     * Store the last token in the position previously occupied by landId
     */
    landIndex[tempTokenId] = indexInArray.add(1);
    landIds[indexInArray] = tempTokenId;
    /**
     * Delete the landIds[last element]
     */
    delete landIds[lastIndexInArray];
    landIds.length = lastIndexInArray;
    /**
     * Drop this landId from both the landIndex and landId list
     */
    landIndex[landId] = 0;
    /**
     * Drop this landId Estate
     */
    landIdEstate[landId] = 0;
    address owner = ownerOf(estateId);
    _updateEstateLandBalance(owner, address(registry), 1);
    registry.safeTransferFrom(this, destinatary, landId);
    emit RemoveLand(estateId, landId, destinatary);
  }
  function _isUpdateAuthorized(address operator, uint256 estateId) internal view returns (bool) {
    address owner = ownerOf(estateId);
    return isApprovedOrOwner(operator, estateId)
      || updateOperator[estateId] == operator
      || updateManager[owner][operator];
  }
  function _isLandUpdateAuthorized(
    address operator,
    uint256 estateId,
    uint256 landId
  )
    internal returns (bool)
  {
    return _isUpdateAuthorized(operator, estateId) || registry.updateOperator(landId) == operator;
  }
  function _bytesToUint(bytes b) internal pure returns (uint256) {
    return uint256(_bytesToBytes32(b));
  }
  function _bytesToBytes32(bytes b) internal pure returns (bytes32) {
    bytes32 out;
    for (uint i = 0; i < b.length; i++) {
      out |= bytes32(b[i] & 0xFF) >> i.mul(8);
    }
    return out;
  }
  function _updateLandData(
    uint256 estateId,
    uint256 landId,
    string data
  )
    internal
    onlyLandUpdateAuthorized(estateId, landId)
  {
    require(landIdEstate[landId] == estateId, "The LAND is not part of the Estate");
    int x;
    int y;
    (x, y) = registry.decodeTokenId(landId);
    registry.updateLandData(x, y, data);
  }
  /**
   * @dev Set a new estate land balance minime token
   * @param _newEstateLandBalance address of the new estate land balance token
   */
  function _setEstateLandBalanceToken(address _newEstateLandBalance) internal {
    require(_newEstateLandBalance != address(0), "New estateLandBalance should not be zero address");
    emit SetEstateLandBalanceToken(estateLandBalance, _newEstateLandBalance);
    estateLandBalance = IMiniMeToken(_newEstateLandBalance);
  }
   /**
   * @dev Register an account balance
   * @notice Register land Balance
   */
  function registerBalance() external {
    require(!registeredBalance[msg.sender], "Register Balance::The user is already registered");
    // Get balance of the sender
    uint256 currentBalance = estateLandBalance.balanceOf(msg.sender);
    if (currentBalance > 0) {
      require(
        estateLandBalance.destroyTokens(msg.sender, currentBalance),
        "Register Balance::Could not destroy tokens"
      );
    }
    // Set balance as registered
    registeredBalance[msg.sender] = true;
    // Get LAND balance
    uint256 newBalance = getLANDsSize(msg.sender);
    // Generate Tokens
    require(
      estateLandBalance.generateTokens(msg.sender, newBalance),
      "Register Balance::Could not generate tokens"
    );
  }
  /**
   * @dev Unregister an account balance
   * @notice Unregister land Balance
   */
  function unregisterBalance() external {
    require(registeredBalance[msg.sender], "Unregister Balance::The user not registered");
    // Set balance as unregistered
    registeredBalance[msg.sender] = false;
    // Get balance
    uint256 currentBalance = estateLandBalance.balanceOf(msg.sender);
    // Destroy Tokens
    require(
      estateLandBalance.destroyTokens(msg.sender, currentBalance),
      "Unregister Balance::Could not destroy tokens"
    );
  }
  /**
   * @dev Update account balances
   * @param _from account
   * @param _to account
   * @param _amount to update
   */
  function _updateEstateLandBalance(address _from, address _to, uint256 _amount) internal {
    if (registeredBalance[_from]) {
      estateLandBalance.destroyTokens(_from, _amount);
    }
    if (registeredBalance[_to]) {
      estateLandBalance.generateTokens(_to, _amount);
    }
  }
  /**
   * @dev Set a estate land balance minime token hardcoded because of the
   * contraint of the proxy for using an owner
   * Mainnet: 0x8568f23f343694650370fe5e254b55bfb704a6c7
   */
  function setEstateLandBalanceToken() external {
    require(estateLandBalance == address(0), "estateLandBalance was set");
    _setEstateLandBalanceToken(address(0x8568f23f343694650370fe5e254b55bfb704a6c7));
  }
}