pragma solidity ^0.4.24;

/**
 * @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) {
    // Gas optimization: this is cheaper than asserting 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    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;
  }
}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  function totalSupply() public view returns (uint256);
  function balanceOf(address who) public view returns (uint256);
  function transfer(address to, uint256 value) public returns (bool);
  event Transfer(address indexed from, address indexed to, uint256 value);
}

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
contract ERC20 is ERC20Basic {
  function allowance(address owner, address spender)
    public view returns (uint256);

  function transferFrom(address from, address to, uint256 value)
    public returns (bool);

  function approve(address spender, uint256 value) public returns (bool);
  event Approval(
    address indexed owner,
    address indexed spender,
    uint256 value
  );
}

/**
 * @title Interface for the polymath ticker registry contract
 */
contract ITickerRegistry {
    /**
    * @notice Check the validity of the symbol
    * @param _symbol token symbol
    * @param _owner address of the owner
    * @param _tokenName Name of the token
    * @return bool
    */
    function checkValidity(string _symbol, address _owner, string _tokenName) public returns(bool);

    /**
    * @notice Returns the owner and timestamp for a given symbol
    * @param _symbol symbol
    */
    function getDetails(string _symbol) public view returns (address, uint256, string, bytes32, bool);

    /**
     * @notice Check the symbol is reserved or not
     * @param _symbol Symbol of the token
     * @return bool
     */
     function isReserved(string _symbol, address _owner, string _tokenName, bytes32 _swarmHash) public returns(bool);

}

/**
 * @title Utility contract for reusable code
 */
contract Util {

   /**
    * @notice changes a string to upper case
    * @param _base string to change
    */
    function upper(string _base) internal pure returns (string) {
        bytes memory _baseBytes = bytes(_base);
        for (uint i = 0; i < _baseBytes.length; i++) {
            bytes1 b1 = _baseBytes[i];
            if (b1 >= 0x61 && b1 <= 0x7A) {
                b1 = bytes1(uint8(b1)-32);
            }
            _baseBytes[i] = b1;
        }
        return string(_baseBytes);
    }

}

/**
 * @title Utility contract to allow pausing and unpausing of certain functions
 */
contract Pausable {

    event Pause(uint256 _timestammp);
    event Unpause(uint256 _timestamp);

    bool public paused = false;

    /**
    * @notice Modifier to make a function callable only when the contract is not paused.
    */
    modifier whenNotPaused() {
        require(!paused);
        _;
    }

    /**
    * @notice Modifier to make a function callable only when the contract is paused.
    */
    modifier whenPaused() {
        require(paused);
        _;
    }

   /**
    * @notice called by the owner to pause, triggers stopped state
    */
    function _pause() internal {
        require(!paused);
        paused = true;
        emit Pause(now);
    }

    /**
    * @notice called by the owner to unpause, returns to normal state
    */
    function _unpause() internal {
        require(paused);
        paused = false;
        emit Unpause(now);
    }

}

/**
 * @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 {
  address public owner;


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


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  constructor() public {
    owner = msg.sender;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(msg.sender == owner);
    _;
  }

  /**
   * @dev Allows the current owner to relinquish control of the contract.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipRenounced(owner);
    owner = address(0);
  }

  /**
   * @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 {
    _transferOwnership(_newOwner);
  }

  /**
   * @dev Transfers control of the contract to a newOwner.
   * @param _newOwner The address to transfer ownership to.
   */
  function _transferOwnership(address _newOwner) internal {
    require(_newOwner != address(0));
    emit OwnershipTransferred(owner, _newOwner);
    owner = _newOwner;
  }
}

/**
 * @title Utility contract to allow owner to retreive any ERC20 sent to the contract
 */
contract ReclaimTokens is Ownable {

    /**
    * @notice Reclaim all ERC20Basic compatible tokens
    * @param _tokenContract The address of the token contract
    */
    function reclaimERC20(address _tokenContract) external onlyOwner {
        require(_tokenContract != address(0));
        ERC20Basic token = ERC20Basic(_tokenContract);
        uint256 balance = token.balanceOf(address(this));
        require(token.transfer(owner, balance));
    }
}

/**
 * @title Core functionality for registry upgradability
 */
contract PolymathRegistry is ReclaimTokens {

    mapping (bytes32 => address) public storedAddresses;

    event LogChangeAddress(string _nameKey, address indexed _oldAddress, address indexed _newAddress);

    /**
     * @notice Get the contract address
     * @param _nameKey is the key for the contract address mapping
     * @return address
     */
    function getAddress(string _nameKey) view public returns(address) {
        bytes32 key = keccak256(bytes(_nameKey));
        require(storedAddresses[key] != address(0), "Invalid address key");
        return storedAddresses[key];
    }

    /**
     * @notice change the contract address
     * @param _nameKey is the key for the contract address mapping
     * @param _newAddress is the new contract address
     */
    function changeAddress(string _nameKey, address _newAddress) public onlyOwner {
        bytes32 key = keccak256(bytes(_nameKey));
        emit LogChangeAddress(_nameKey, storedAddresses[key], _newAddress);
        storedAddresses[key] = _newAddress;
    }


}

contract RegistryUpdater is Ownable {

    address public polymathRegistry;
    address public moduleRegistry;
    address public securityTokenRegistry;
    address public tickerRegistry;
    address public polyToken;

    constructor (address _polymathRegistry) public {
        require(_polymathRegistry != address(0));
        polymathRegistry = _polymathRegistry;
    }

    function updateFromRegistry() onlyOwner public {
        moduleRegistry = PolymathRegistry(polymathRegistry).getAddress("ModuleRegistry");
        securityTokenRegistry = PolymathRegistry(polymathRegistry).getAddress("SecurityTokenRegistry");
        tickerRegistry = PolymathRegistry(polymathRegistry).getAddress("TickerRegistry");
        polyToken = PolymathRegistry(polymathRegistry).getAddress("PolyToken");
    }

}

/**
 * @title Registry contract for issuers to reserve their security token symbols
 * @notice Allows issuers to reserve their token symbols ahead of actually generating their security token.
 * @dev SecurityTokenRegistry would reference this contract and ensure that a token symbol exists here and only its owner can deploy the token with that symbol.
 */
contract TickerRegistry is ITickerRegistry, Util, Pausable, RegistryUpdater, ReclaimTokens {

    using SafeMath for uint256;
    // constant variable to check the validity to use the symbol
    // For now it's value is 15 days;
    uint256 public expiryLimit = 15 * 1 days;

    // Details of the symbol that get registered with the polymath platform
    struct SymbolDetails {
        address owner;
        uint256 timestamp;
        string tokenName;
        bytes32 swarmHash;
        bool status;
    }

    // Storage of symbols correspond to their details.
    mapping(string => SymbolDetails) registeredSymbols;

    // Emit after the symbol registration
    event LogRegisterTicker(address indexed _owner, string _symbol, string _name, bytes32 _swarmHash, uint256 indexed _timestamp);
    // Emit when the token symbol expiry get changed
    event LogChangeExpiryLimit(uint256 _oldExpiry, uint256 _newExpiry);

    // Registration fee in POLY base 18 decimals
    uint256 public registrationFee;
    // Emit when changePolyRegisterationFee is called
    event LogChangePolyRegisterationFee(uint256 _oldFee, uint256 _newFee);

    constructor (address _polymathRegistry, uint256 _registrationFee) public
    RegistryUpdater(_polymathRegistry)
    {
        registrationFee = _registrationFee;
    }

    /**
     * @notice Register the token symbol for its particular owner
     * @notice Once the token symbol is registered to its owner then no other issuer can claim
     * @notice its ownership. If the symbol expires and its issuer hasn't used it, then someone else can take it.
     * @param _symbol token symbol
     * @param _tokenName Name of the token
     * @param _owner Address of the owner of the token
     * @param _swarmHash Off-chain details of the issuer and token
     */
    function registerTicker(address _owner, string _symbol, string _tokenName, bytes32 _swarmHash) public whenNotPaused {
        require(_owner != address(0), "Owner should not be 0x");
        require(bytes(_symbol).length > 0 && bytes(_symbol).length <= 10, "Ticker length should always between 0 & 10");
        if(registrationFee > 0)
            require(ERC20(polyToken).transferFrom(msg.sender, this, registrationFee), "Failed transferFrom because of sufficent Allowance is not provided");
        string memory symbol = upper(_symbol);
        require(expiryCheck(symbol), "Ticker is already reserved");
        registeredSymbols[symbol] = SymbolDetails(_owner, now, _tokenName, _swarmHash, false);
        emit LogRegisterTicker (_owner, symbol, _tokenName, _swarmHash, now);
    }

    /**
     * @notice Change the expiry time for the token symbol
     * @param _newExpiry new time period for token symbol expiry
     */
    function changeExpiryLimit(uint256 _newExpiry) public onlyOwner {
        require(_newExpiry >= 1 days, "Expiry should greater than or equal to 1 day");
        uint256 _oldExpiry = expiryLimit;
        expiryLimit = _newExpiry;
        emit LogChangeExpiryLimit(_oldExpiry, _newExpiry);
    }

    /**
     * @notice Check the validity of the symbol
     * @param _symbol token symbol
     * @param _owner address of the owner
     * @param _tokenName Name of the token
     * @return bool
     */
    function checkValidity(string _symbol, address _owner, string _tokenName) public returns(bool) {
        string memory symbol = upper(_symbol);
        require(msg.sender == securityTokenRegistry, "msg.sender should be SecurityTokenRegistry contract");
        require(registeredSymbols[symbol].status != true, "Symbol status should not equal to true");
        require(registeredSymbols[symbol].owner == _owner, "Owner of the symbol should matched with the requested issuer address");
        require(registeredSymbols[symbol].timestamp.add(expiryLimit) >= now, "Ticker should not be expired");
        registeredSymbols[symbol].tokenName = _tokenName;
        registeredSymbols[symbol].status = true;
        return true;
    }

    /**
     * @notice Check the symbol is reserved or not
     * @param _symbol Symbol of the token
     * @param _owner Owner of the token
     * @param _tokenName Name of the token
     * @param _swarmHash off-chain hash
     * @return bool
     */
     function isReserved(string _symbol, address _owner, string _tokenName, bytes32 _swarmHash) public returns(bool) {
        string memory symbol = upper(_symbol);
        require(msg.sender == securityTokenRegistry, "msg.sender should be SecurityTokenRegistry contract");
        if (registeredSymbols[symbol].owner == _owner && !expiryCheck(_symbol)) {
            registeredSymbols[symbol].status = true;
            return false;
        }
        else if (registeredSymbols[symbol].owner == address(0) || expiryCheck(symbol)) {
            registeredSymbols[symbol] = SymbolDetails(_owner, now, _tokenName, _swarmHash, true);
            emit LogRegisterTicker (_owner, symbol, _tokenName, _swarmHash, now);
            return false;
        } else
            return true;
     }

    /**
     * @notice Returns the owner and timestamp for a given symbol
     * @param _symbol symbol
     * @return address
     * @return uint256
     * @return string
     * @return bytes32
     * @return bool
     */
    function getDetails(string _symbol) public view returns (address, uint256, string, bytes32, bool) {
        string memory symbol = upper(_symbol);
        if (registeredSymbols[symbol].status == true||registeredSymbols[symbol].timestamp.add(expiryLimit) > now) {
            return
            (
                registeredSymbols[symbol].owner,
                registeredSymbols[symbol].timestamp,
                registeredSymbols[symbol].tokenName,
                registeredSymbols[symbol].swarmHash,
                registeredSymbols[symbol].status
            );
        }else
            return (address(0), uint256(0), "", bytes32(0), false);
    }

    /**
     * @notice To re-initialize the token symbol details if symbol validity expires
     * @param _symbol token symbol
     * @return bool
     */
    function expiryCheck(string _symbol) internal returns(bool) {
        if (registeredSymbols[_symbol].owner != address(0)) {
            if (now > registeredSymbols[_symbol].timestamp.add(expiryLimit) && registeredSymbols[_symbol].status != true) {
                registeredSymbols[_symbol] = SymbolDetails(address(0), uint256(0), "", bytes32(0), false);
                return true;
            }else
                return false;
        }
        return true;
    }

    /**
     * @notice set the ticker registration fee in POLY tokens
     * @param _registrationFee registration fee in POLY tokens (base 18 decimals)
     */
    function changePolyRegisterationFee(uint256 _registrationFee) public onlyOwner {
        require(registrationFee != _registrationFee);
        emit LogChangePolyRegisterationFee(registrationFee, _registrationFee);
        registrationFee = _registrationFee;
    }

     /**
     * @notice pause registration function
     */
    function unpause() public onlyOwner  {
        _unpause();
    }

    /**
     * @notice unpause registration function
     */
    function pause() public onlyOwner {
        _pause();
    }

}