pragma solidity ^0.4.19;

contract Ownable {
    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 Ownable() 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 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));
        OwnershipTransferred(owner, newOwner);
        owner = newOwner;
    }
}

/**
 * @title ERC20Basic
 * @dev Simpler version of ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/179
 */
contract ERC20Basic {
  uint256 public totalSupply;
  function balanceOf(address who) public constant 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 constant 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 SafeMath
 * @dev Math operations with safety checks that throw on error
 */
library SafeMath {
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  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 c;
  }

  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}

/**
 * @title Basic token
 * @dev Basic version of StandardToken, with no allowances.
 */
contract BasicToken is ERC20Basic {
  using SafeMath for uint256;

  mapping(address => uint256) balances;

  /**
  * @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){
    balances[msg.sender] = balances[msg.sender].sub(_value);
    balances[_to] = balances[_to].add(_value);
    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 constant returns (uint256 balance) {
    return balances[_owner];
  }
}

/**
 * @title Standard ERC20 token
 *
 * @dev Implementation of the basic standard token.
 * @dev https://github.com/ethereum/EIPs/issues/20
 * @dev Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
 */
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 amout of tokens to be transfered
   */
  function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
    require(_to != address(0));

    balances[_to] = balances[_to].add(_value);
    balances[_from] = balances[_from].sub(_value);
    allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);
    Transfer(_from, _to, _value);
    return true;
  }

  /**
  * @dev Aprove the passed address to spend the specified amount of tokens on behalf of msg.sender.
  * @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) {

    // To change the approve amount you first have to reduce the addresses`
    //  allowance to zero by calling `approve(_spender, 0)` if it is not
    //  already 0 to mitigate the race condition described here:
    //  https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
    require((_value == 0) || (allowed[msg.sender][_spender] == 0));

    allowed[msg.sender][_spender] = _value;
    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 specifing the amount of tokens still avaible for the spender.
   */
  function allowance(address _owner, address _spender) public constant returns (uint256 remaining) {
    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));
    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);
    }
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }
}

/**
 * @title Mintable token
 * @dev Simple ERC20 Token example, with mintable token creation
 * @dev Issue: * https://github.com/OpenZeppelin/zeppelin-solidity/issues/120
 * Based on code by TokenMarketNet: https://github.com/TokenMarketNet/ico/blob/master/contracts/MintableToken.sol
 */

contract MintableToken is StandardToken, Ownable {
  event Mint(address indexed to, uint256 amount);
  event MintFinished();

  bool public mintingFinished = false;

  modifier canMint() {
    require(!mintingFinished);
    _;
  }

  /**
  * @dev Function to mint tokens
  * @param _to The address that will recieve 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) onlyOwner canMint public returns (bool) {
    totalSupply = totalSupply.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    Transfer(0X0, _to, _amount);
    return true;
  }

  /**
  * @dev Function to stop minting new tokens.
  * @return True if the operation was successful.
   */
  function finishMinting() onlyOwner public returns (bool) {
    mintingFinished = true;
    MintFinished();
    return true;
  }
}

contract MITx_Token is MintableToken {
  string public name = "Morpheus Infrastructure Token";
  string public symbol = "MITx";
  uint256 public decimals = 18;

  bool public tradingStarted = false;

  /**
  * @dev modifier that throws if trading has not started yet
   */
  modifier hasStartedTrading() {
    require(tradingStarted);
    _;
  }

  /**
  * @dev Allows the owner to enable the trading. This can not be undone
  */
  function startTrading() public onlyOwner {
    tradingStarted = true;
  }

  /**
   * @dev Allows anyone to transfer the MiT tokens once trading has started
   * @param _to the recipient address of the tokens.
   * @param _value number of tokens to be transfered.
   */
  function transfer(address _to, uint _value) hasStartedTrading public returns (bool) {
    return super.transfer(_to, _value);
  }

  /**
  * @dev Allows anyone to transfer the MiT tokens once trading has started
  * @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 uint the amout of tokens to be transfered
   */
  function transferFrom(address _from, address _to, uint _value) hasStartedTrading public returns (bool) {
    return super.transferFrom(_from, _to, _value);
  }

  function emergencyERC20Drain( ERC20 oddToken, uint amount ) public {
    oddToken.transfer(owner, amount);
  }
}

contract MITxSubscriptionPayment is Ownable {
    using SafeMath for uint256;
    MITx_Token public token;

    event Pay(uint _amount, address _from, address subscriptions, string _tierID);
    
    constructor(MITx_Token _token) public {
        token = _token;
    }

     // call when user purchase an application from the App Store
    function pay(uint256 _amount, address subscriptions, string _tierID) public returns (bool) {
        require(subscriptions != 0x0);

        //Verifies if the contract can spend the needed amount of MITx tokens on behalf of the user
        MITx_Token mitx_iab = MITx_Token(token);
        uint256 aux =  mitx_iab.allowance(msg.sender, address(this));
        require(aux >= _amount);

        //Perform the transactions to the ML AppStore 
        mitx_iab.transferFrom(msg.sender, subscriptions, _amount);

        emit Pay(_amount, msg.sender, subscriptions, _tierID);

        return true;
    }
    
    function setMITx_Token(MITx_Token _token) public onlyOwner{
        token = _token;
    }
    
}