pragma solidity ^0.4.25;

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;
    require(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) {
    require(_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;
    require(c >= _a);
    return c;
  }
}

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.
   * @notice Renouncing to ownership will leave the contract without an owner.
   * It will not be possible to call the functions with the `onlyOwner`
   * modifier anymore.
   */
  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;
  }
}

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);
}

contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) internal balances;

  uint256 internal totalSupply_;

  /**
  * @dev Total number of tokens in existence
  */
  function totalSupply() public view returns (uint256) {
    return totalSupply_;
  }

  /**
  * @dev Transfer token for a specified address
  * @param _to The address to transfer to.
  * @param _value The amount to be transferred.
  */
  function transfer(address _to, uint256 _value) public returns (bool) {
    require(_value <= balances[msg.sender]);
    require(_to != address(0));

    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    emit Transfer(msg.sender, _to, _value);
    return true;
  }

  /**
  * @dev Gets the balance of the specified address.
  * @param _owner The address to query the the balance of.
  * @return An uint256 representing the amount owned by the passed address.
  */
  function balanceOf(address _owner) public view returns (uint256) {
    return balances[_owner];
  }

}

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
  );
}

contract StandardToken is ERC20, BasicToken {

  mapping (address => mapping (address => uint256)) internal allowed;


  /**
   * @dev Transfer tokens from one address to another
   * @param _from address The address which you want to send tokens from
   * @param _to address The address which you want to transfer to
   * @param _value uint256 the amount of tokens to be transferred
   */
  function transferFrom(
    address _from,
    address _to,
    uint256 _value
  )
    public
    returns (bool)
  {
    require(_value <= balances[_from]);
    require(_value <= allowed[_from][msg.sender]);
    require(_to != address(0));

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    emit Transfer(_from, _to, _value);
    return true;
  }

  /**
   * @dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender.
   * Beware that changing an allowance with this method brings the risk that someone may use both the old
   * and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this
   * race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   * @param _spender The address which will spend the funds.
   * @param _value The amount of tokens to be spent.
   */
  function approve(address _spender, uint256 _value) public returns (bool) {
    allowed[msg.sender][_spender] = _value;
    emit Approval(msg.sender, _spender, _value);
    return true;
  }

  /**
   * @dev Function to check the amount of tokens that an owner allowed to a spender.
   * @param _owner address The address which owns the funds.
   * @param _spender address The address which will spend the funds.
   * @return A uint256 specifying the amount of tokens still available for the spender.
   */
  function allowance(
    address _owner,
    address _spender
   )
    public
    view
    returns (uint256)
  {
    return allowed[_owner][_spender];
  }

  /**
   * @dev Increase the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed[_spender] == 0. To increment
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _addedValue The amount of tokens to increase the allowance by.
   */
  function increaseApproval(
    address _spender,
    uint256 _addedValue
  )
    public
    returns (bool)
  {
    allowed[msg.sender][_spender] = (
      allowed[msg.sender][_spender].add(_addedValue));
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  /**
   * @dev Decrease the amount of tokens that an owner allowed to a spender.
   * approve should be called when allowed[_spender] == 0. To decrement
   * allowed value is better to use this function to avoid 2 calls (and wait until
   * the first transaction is mined)
   * From MonolithDAO Token.sol
   * @param _spender The address which will spend the funds.
   * @param _subtractedValue The amount of tokens to decrease the allowance by.
   */
  function decreaseApproval(
    address _spender,
    uint256 _subtractedValue
  )
    public
    returns (bool)
  {
    uint256 oldValue = allowed[msg.sender][_spender];
    if (_subtractedValue >= oldValue) {
      allowed[msg.sender][_spender] = 0;
    } else {
      allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
    }
    emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

}

contract MintableToken is StandardToken, Ownable {
  event Mint(address indexed to, uint256 amount);
  event MintFinished();

  bool public mintingFinished = false;


  modifier canMint() {
    require(!mintingFinished);
    _;
  }

  modifier hasMintPermission() {
    require(msg.sender == owner);
    _;
  }

  /**
   * @dev Function to mint tokens
   * @param _to The address that will receive the minted tokens.
   * @param _amount The amount of tokens to mint.
   * @return A boolean that indicates if the operation was successful.
   */
  function mint(
    address _to,
    uint256 _amount
  )
    public
    hasMintPermission
    canMint
    returns (bool)
  {
    totalSupply_ = totalSupply_.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    emit Mint(_to, _amount);
    emit Transfer(address(0), _to, _amount);
    return true;
  }

  /**
   * @dev Function to stop minting new tokens.
   * @return True if the operation was successful.
   */
  function finishMinting() public onlyOwner canMint returns (bool) {
    mintingFinished = true;
    emit MintFinished();
    return true;
  }
}

contract ReleasableToken is ERC20, Ownable {

    /* The finalizer contract that allows unlift the transfer limits on this token */
    address public releaseAgent;

    /** A crowdsale contract can release us to the wild if the sale is a success. If false we are are in transfer lock up period.*/
    bool public released = false;

    /** Map of agents that are allowed to transfer tokens regardless of the lock down period. These are crowdsale contracts and possible the team multisig itself. */
    mapping(address => bool) public transferAgents;

    /**
     * Limit token transfer until the crowdsale is over.
     *
     */
    modifier canTransfer(address _sender) {
        require(released || transferAgents[_sender], "For the token to be able to transfer: it's required that the crowdsale is in released state; or the sender is a transfer agent.");
        _;
    }

    /**
     * Set the contract that can call release and make the token transferable.
     *
     * Design choice. Allow reset the release agent to fix fat finger mistakes.
     */
    function setReleaseAgent(address addr) public onlyOwner inReleaseState(false) {

        // We don't do interface check here as we might want to a normal wallet address to act as a release agent
        releaseAgent = addr;
    }

    /**
     * Owner can allow a particular address (a crowdsale contract) to transfer tokens despite the lock up period.
     */
    function setTransferAgent(address addr, bool state) public onlyOwner inReleaseState(false) {
        transferAgents[addr] = state;
    }

    /**
     * One way function to release the tokens to the wild.
     *
     * Can be called only from the release agent that is the final sale contract. It is only called if the crowdsale has been success (first milestone reached).
     */
    function releaseTokenTransfer() public onlyReleaseAgent {
        released = true;
    }

    /** The function can be called only before or after the tokens have been released */
    modifier inReleaseState(bool releaseState) {
        require(releaseState == released, "It's required that the state to check aligns with the released flag.");
        _;
    }

    /** The function can be called only by a whitelisted release agent. */
    modifier onlyReleaseAgent() {
        require(msg.sender == releaseAgent, "Message sender is required to be a release agent.");
        _;
    }

    function transfer(address _to, uint _value) public canTransfer(msg.sender) returns (bool success) {
        // Call StandardToken.transfer()
        return super.transfer(_to, _value);
    }

    function transferFrom(address _from, address _to, uint _value) public canTransfer(_from) returns (bool success) {
        // Call StandardToken.transferForm()
        return super.transferFrom(_from, _to, _value);
    }

}

contract UpgradeableToken is StandardToken {

    using SafeMath for uint256;


    /** Contract / person who can set the upgrade path. This can be the same as team multisig wallet, as what it is with its default value. */
    address public upgradeMaster;

    /** The next contract where the tokens will be migrated. */
    UpgradeAgent public upgradeAgent;

    /** How many tokens we have upgraded by now. */
    uint256 public totalUpgraded;

    /**
     * Upgrade states.
     *
     * - NotAllowed: The child contract has not reached a condition where the upgrade can begin
     * - WaitingForAgent: Token allows upgrade, but we don't have a new agent yet
     * - ReadyToUpgrade: The agent is set and the balance holders can upgrade their tokens
     *
     */
    enum UpgradeState {Unknown, NotAllowed, WaitingForAgent, ReadyToUpgrade}

    /**
     * Somebody has upgraded some of his tokens.
     */
    event Upgrade(address indexed _from, address indexed _to, uint256 _value);

    /**
     * New upgrade agent available.
     */
    event UpgradeAgentSet(address agent);

    /**
     * Do not allow construction without upgrade master set.
     */
    constructor(address _upgradeMaster) public {
        upgradeMaster = _upgradeMaster;
    }

    /**
     * Allow the token holder to upgrade some of their tokens to a new contract.
     */
    function upgrade(uint256 value) public {

        UpgradeState state = getUpgradeState();

        require(state == UpgradeState.ReadyToUpgrade, "It's required that the upgrade state is ready.");

        // Validate input value.
        require(value > 0, "The upgrade value is required to be above 0.");

        balances[msg.sender] = balances[msg.sender].sub(value);

        // Take tokens out from circulation
        totalSupply_ = totalSupply_.sub(value);
        totalUpgraded = totalUpgraded.add(value);

        // Upgrade agent reissues the tokens
        upgradeAgent.upgradeFrom(msg.sender, value);
        emit Upgrade(msg.sender, upgradeAgent, value);
    }

    /**
     * Set an upgrade agent that handles
     */
    function setUpgradeAgent(address agent) external {

        require(canUpgrade(), "It's required to be in canUpgrade() condition when setting upgrade agent.");

        require(agent != address(0), "Agent is required to be an non-empty address when setting upgrade agent.");

        // Only a master can designate the next agent
        require(msg.sender == upgradeMaster, "Message sender is required to be the upgradeMaster when setting upgrade agent.");

        // Upgrade has already begun for an agent
        require(getUpgradeState() != UpgradeState.ReadyToUpgrade, "Upgrade state is required to not be upgrading when setting upgrade agent.");

        require(address(upgradeAgent) == address(0), "upgradeAgent once set, cannot be reset");

        upgradeAgent = UpgradeAgent(agent);

        // Bad interface
        require(upgradeAgent.isUpgradeAgent(), "The provided updateAgent contract is required to be compliant to the UpgradeAgent interface method when setting upgrade agent.");

        // Make sure that token supplies match in source and target
        require(upgradeAgent.originalSupply() == totalSupply_, "The provided upgradeAgent contract's originalSupply is required to be equivalent to existing contract's totalSupply_ when setting upgrade agent.");

        emit UpgradeAgentSet(upgradeAgent);
    }

    /**
     * Get the state of the token upgrade.
     */
    function getUpgradeState() public view returns (UpgradeState) {
        if (!canUpgrade()) return UpgradeState.NotAllowed;
        else if (address(upgradeAgent) == address(0)) return UpgradeState.WaitingForAgent;
        else return UpgradeState.ReadyToUpgrade;
    }

    /**
     * Change the upgrade master.
     *
     * This allows us to set a new owner for the upgrade mechanism.
     */
    function setUpgradeMaster(address master) public {
        require(master != address(0), "The provided upgradeMaster is required to be a non-empty address when setting upgrade master.");

        require(msg.sender == upgradeMaster, "Message sender is required to be the original upgradeMaster when setting (new) upgrade master.");

        upgradeMaster = master;
    }

    bool canUpgrade_ = true;

    /**
     * Child contract can enable to provide the condition when the upgrade can begin.
     */
    function canUpgrade() public view returns (bool) {
        return canUpgrade_;
    }
}

contract Jobchain is ReleasableToken, MintableToken, UpgradeableToken {

    event UpdatedTokenInformation(string newName, string newSymbol);

    string public name;

    string public symbol;

    uint8 public decimals;

    address public VerificationNodesWallet;
    address public LaunchIncentiveWallet;
    address public capitalReserveWallet;
    address public ecosystemdevelopmentWallet;
    address public InitialFundingWallet;

    /**
     * Construct the token.
     *
     * This token must be created through a team multisig wallet, so that it is owned by that wallet.
     *
     * @param _name Token name
     * @param _symbol Token symbol - should be all caps
     * @param _initialSupply How many tokens we start with
     * @param _decimals Number of decimal places
     * @param _mintable Are new tokens created over the crowdsale or do we distribute only the initial supply? Note that when the token becomes transferable the minting always ends.
     */
    constructor(string _name, string _symbol, uint256 _initialSupply, uint8 _decimals, bool _mintable,
        address _VerificationNodesWallet,
        address _LaunchIncentiveWallet,
        address _capitalReserveWallet,
        address _ecosystemdevelopmentWallet,
        address _InitialFundingWallet)
    public UpgradeableToken(msg.sender) {

        // Create any address, can be transferred
        // to team multisig via changeOwner(),
        // also remember to call setUpgradeMaster()
        owner = msg.sender;
        releaseAgent = owner;

        name = _name;
        symbol = _symbol;

        decimals = _decimals;

        VerificationNodesWallet = _VerificationNodesWallet;
        LaunchIncentiveWallet = _LaunchIncentiveWallet;
        capitalReserveWallet = _capitalReserveWallet;
        ecosystemdevelopmentWallet = _ecosystemdevelopmentWallet;
        InitialFundingWallet = _InitialFundingWallet;

        if (_initialSupply > 0) {
            require((_initialSupply % 10) == 0, "_initialSupply has to be a mulitple of 10");
            uint256 twentyfivePerCent = _initialSupply.mul(25).div(100);
            uint256 twentyPerCent = _initialSupply.mul(2).div(10);
            uint256 tenPerCent = _initialSupply.div(10);

            mint(VerificationNodesWallet, twentyPerCent);

            mint(LaunchIncentiveWallet, twentyfivePerCent);

            mint(capitalReserveWallet, twentyfivePerCent);

            mint(ecosystemdevelopmentWallet, twentyPerCent);

            mint(InitialFundingWallet, tenPerCent);

        }

        // No more new supply allowed after the token creation
        if (!_mintable) {
            finishMinting();
            require(totalSupply_ > 0, "Total supply is required to be above 0 if the token is not mintable.");
        }

    }

    /**
     * When token is released to be transferable, enforce no new tokens can be created.
     */
    function releaseTokenTransfer() public onlyReleaseAgent {
        mintingFinished = true;
        super.releaseTokenTransfer();
    }

    /**
     * Allow upgrade agent functionality kick in only if the crowdsale was success.
     */
    function canUpgrade() public view returns (bool) {
        return released && super.canUpgrade();
    }

    // Total supply
    function totalSupply() public view returns (uint) {
        return totalSupply_.sub(balances[address(0)]);
    }

}

contract UpgradeAgent {

    uint public originalSupply;

    /** Interface marker */
    function isUpgradeAgent() public pure returns (bool) {
        return true;
    }

    function upgradeFrom(address _from, uint256 _value) public;

}