pragma solidity ^0.4.11;

/**
 * @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 OwnershipTransferred(address indexed previousOwner, address indexed newOwner);


  /**
   * @dev The Ownable constructor sets the original `owner` of the contract to the sender
   * account.
   */
  function Ownable() {
    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) onlyOwner public {
    require(newOwner != address(0));
    OwnershipTransferred(owner, newOwner);
    owner = newOwner;
  }

}

library SafeMath {
  function mul(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function div(uint256 a, uint256 b) internal constant 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 constant returns (uint256) {
    assert(b <= a);
    return a - b;
  }

  function add(uint256 a, uint256 b) internal constant returns (uint256) {
    uint256 c = a + b;
    assert(c >= a);
    return c;
  }
}

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);
}

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) {
    require(_to != address(0));

    // SafeMath.sub will throw if there is not enough balance.
    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)) 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(_to != address(0));

    uint256 _allowance = allowed[_from][msg.sender];

    // Check is not needed because sub(_allowance, _value) will already throw if this condition is not met
    // require (_value <= _allowance);

    balances[_from] = balances[_from].sub(_value);
    balances[_to] = balances[_to].add(_value);
    allowed[_from][msg.sender] = _allowance.sub(_value);
    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;
    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 constant returns (uint256 remaining) {
    return allowed[_owner][_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
   */
  function increaseApproval (address _spender, uint _addedValue)
    returns (bool success) {
    allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
    Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
    return true;
  }

  function decreaseApproval (address _spender, uint _subtractedValue)
    returns (bool success) {
    uint 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;
  }

}

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 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) onlyOwner canMint public returns (bool) {
    totalSupply = totalSupply.add(_amount);
    balances[_to] = balances[_to].add(_amount);
    Mint(_to, _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;
  }
}

/**
 * @title BetrToken
 * @dev Betr ERC20 Token that can be minted.
 * It is meant to be used in sether crowdsale contract.
 */
contract BetrToken is MintableToken {

    string public constant name = "BETer";
    string public constant symbol = "BTR";
    uint8 public constant decimals = 18;

    function getTotalSupply() public returns (uint256) {
        return totalSupply;
    }
}

/**
 * @title BetrBaseCrowdsale
 * @dev BetrBaseCrowdsale is a base contract for managing a sether token crowdsale.
 */
contract BetrCrowdsale is Ownable {
  using SafeMath for uint256;

    // The token being sold
    BetrToken public token;

    // address where funds are collected
    address public wallet;

    // how many finney per token
    uint256 public rate;

    // amount of raised money in wei
    uint256 public weiRaised;

    uint256 public constant TEAM_LIMIT = 225 * (10 ** 6) * (10 ** 18);
    uint256 public constant PRESALE_LIMIT = 275 * (10 ** 6) * (10 ** 18);
    uint public constant PRESALE_BONUS = 30;
    uint saleStage = 0; //0: presale with bonus, !0: normal sale without bonus
    bool public isFinalized = false;

    /**
    * event for token purchase logging
    * @param purchaser who paid for the tokens
    * @param beneficiary who got the tokens
    * @param value weis paid for purchase
    * @param amount amount of tokens purchased
    */
    event BetrTokenPurchase(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);

    function BetrCrowdsale(uint256 _rate, address _wallet, address _tok_addr) {
        require(_rate > 0);
        require(_wallet != address(0));

        token = BetrToken(_tok_addr);
        rate = _rate;
        wallet = _wallet;
    }

    // fallback function can be used to buy tokens
    function () payable {
        buyTokens(msg.sender);
    }

    // low level token purchase function
    function buyTokens(address beneficiary) public payable {
        require(beneficiary != address(0));
        require(validPurchase());
        require(!isFinalized);

        uint256 weiAmount = msg.value;

        // calculate token amount to be created
        uint256 tokens = computeTokens(weiAmount);

        require(isWithinTokenAllocLimit(tokens));

        // update state
        weiRaised = weiRaised.add(weiAmount);

        token.mint(beneficiary, tokens);

        BetrTokenPurchase(msg.sender, beneficiary, weiAmount, tokens);

        forwardFunds();
    }


    // send ether to the fund collection wallet
    function forwardFunds() internal {
        wallet.transfer(msg.value);
    }

    // @return true if the transaction can buy tokens
    function validPurchase() internal constant returns (bool) {
        bool nonZeroPurchase = msg.value != 0;
        return nonZeroPurchase;
    }
    
    //Override this method with token distribution strategy
    function computeTokens(uint256 weiAmount) internal returns (uint256) {
        //To be overriden
        uint256 appliedBonus = 0;
	    if (saleStage == 0) {
             appliedBonus = PRESALE_BONUS;
        }

        return weiAmount.mul(100).mul(100 + appliedBonus).div(rate);
    }

    //Override this method with token limitation strategy
    function isWithinTokenAllocLimit(uint256 _tokens) internal returns (bool) {
        //To be overriden
        return token.getTotalSupply().add(_tokens) <= PRESALE_LIMIT;
    }

    function setStage(uint stage) onlyOwner public {
        require(!isFinalized);
        saleStage = stage;
    }

    /**
    * @dev Must be called after crowdsale ends, to do some extra finalization
    * work. Calls the contract's finalization function.
    */
    function finalize() onlyOwner public {
        require(!isFinalized);
    
        uint256 ownerShareTokens = TEAM_LIMIT;
        token.mint(wallet, ownerShareTokens);
        
        isFinalized = true;
    }
}