contract StandardTokenProtocol {

    function totalSupply() constant returns (uint256 totalSupply) {}
    function balanceOf(address _owner) constant returns (uint256 balance) {}
    function transfer(address _recipient, uint256 _value) returns (bool success) {}
    function transferFrom(address _from, address _recipient, uint256 _value) returns (bool success) {}
    function approve(address _spender, uint256 _value) returns (bool success) {}
    function allowance(address _owner, address _spender) constant returns (uint256 remaining) {}

    event Transfer(address indexed _from, address indexed _recipient, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);

}


contract StandardToken is StandardTokenProtocol {

    modifier when_can_transfer(address _from, uint256 _value) {
        if (balances[_from] >= _value) _;
    }

    modifier when_can_receive(address _recipient, uint256 _value) {
        if (balances[_recipient] + _value > balances[_recipient]) _;
    }

    modifier when_is_allowed(address _from, address _delegate, uint256 _value) {
        if (allowed[_from][_delegate] >= _value) _;
    }

    function transfer(address _recipient, uint256 _value)
        when_can_transfer(msg.sender, _value)
        when_can_receive(_recipient, _value)
        returns (bool o_success)
    {
        balances[msg.sender] -= _value;
        balances[_recipient] += _value;
        Transfer(msg.sender, _recipient, _value);
        return true;
    }

    function transferFrom(address _from, address _recipient, uint256 _value)
        when_can_transfer(_from, _value)
        when_can_receive(_recipient, _value)
        when_is_allowed(_from, msg.sender, _value)
        returns (bool o_success)
    {
        allowed[_from][msg.sender] -= _value;
        balances[_from] -= _value;
        balances[_recipient] += _value;
        Transfer(_from, _recipient, _value);
        return true;
    }

    function balanceOf(address _owner) constant returns (uint256 balance) {
        return balances[_owner];
    }

    function approve(address _spender, uint256 _value) returns (bool o_success) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }

    function allowance(address _owner, address _spender) constant returns (uint256 o_remaining) {
        return allowed[_owner][_spender];
    }

    mapping (address => uint256) balances;
    mapping (address => mapping (address => uint256)) allowed;
    uint256 public totalSupply;

}

contract GUPToken is StandardToken {

  //FIELDS
  //CONSTANTS
  uint public constant LOCKOUT_PERIOD = 1 years; //time after end date that illiquid GUP can be transferred

  //ASSIGNED IN INITIALIZATION
  uint public endMintingTime; //Time in seconds no more tokens can be created
  address public minter; //address of the account which may mint new tokens

  mapping (address => uint) public illiquidBalance; //Balance of 'Frozen funds'

  //MODIFIERS
  //Can only be called by contribution contract.
  modifier only_minter {
    if (msg.sender != minter) throw;
    _;
  }

  // Can only be called if illiquid tokens may be transformed into liquid.
  // This happens when `LOCKOUT_PERIOD` of time passes after `endMintingTime`.
  modifier when_thawable {
    if (now < endMintingTime + LOCKOUT_PERIOD) throw;
    _;
  }

  // Can only be called if (liquid) tokens may be transferred. Happens
  // immediately after `endMintingTime`.
  modifier when_transferable {
    if (now < endMintingTime) throw;
    _;
  }

  // Can only be called if the `crowdfunder` is allowed to mint tokens. Any
  // time before `endMintingTime`.
  modifier when_mintable {
    if (now >= endMintingTime) throw;
    _;
  }

  // Initialization contract assigns address of crowdfund contract and end time.
  function GUPToken(address _minter, uint _endMintingTime) {
    endMintingTime = _endMintingTime;
    minter = _minter;
  }

  // Fallback function throws when called.
  function() {
    throw;
  }

  // Create new tokens when called by the crowdfund contract.
  // Only callable before the end time.
  function createToken(address _recipient, uint _value)
    when_mintable
    only_minter
    returns (bool o_success)
  {
    balances[_recipient] += _value;
    totalSupply += _value;
    return true;
  }

  // Create an illiquidBalance which cannot be traded until end of lockout period.
  // Can only be called by crowdfund contract befor the end time.
  function createIlliquidToken(address _recipient, uint _value)
    when_mintable
    only_minter
    returns (bool o_success)
  {
    illiquidBalance[_recipient] += _value;
    totalSupply += _value;
    return true;
  }

  // Make sender's illiquid balance liquid when called after lockout period.
  function makeLiquid()
    when_thawable
    returns (bool o_success)
  {
    balances[msg.sender] += illiquidBalance[msg.sender];
    illiquidBalance[msg.sender] = 0;
    return true;
  }

  // Transfer amount of tokens from sender account to recipient.
  // Only callable after the crowd fund end date.
  function transfer(address _recipient, uint _amount)
    when_transferable
    returns (bool o_success)
  {
    return super.transfer(_recipient, _amount);
  }

  // Transfer amount of tokens from a specified address to a recipient.
  // Only callable after the crowd fund end date.
  function transferFrom(address _from, address _recipient, uint _amount)
    when_transferable
    returns (bool o_success)
  {
    return super.transferFrom(_from, _recipient, _amount);
  }
}

contract SafeMath {

  function assert(bool assertion) internal {
    if (!assertion) throw;
  }

  function safeMul(uint a, uint b) internal returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeDiv(uint a, uint b) internal returns (uint) {
    assert(b > 0);
    uint c = a / b;
    assert(a == b * c + a % b);
    return c;
  }

}

contract Contribution is SafeMath {

  //FIELDS

  //CONSTANTS
  //Time limits
  uint public constant STAGE_ONE_TIME_END = 1 hours;
  uint public constant STAGE_TWO_TIME_END = 3 days;
  uint public constant STAGE_THREE_TIME_END = 2 weeks;
  uint public constant STAGE_FOUR_TIME_END = 4 weeks;
  //Prices of GUP
  uint public constant PRICE_STAGE_ONE = 400000;
  uint public constant PRICE_STAGE_TWO = 366000;
  uint public constant PRICE_STAGE_THREE = 333000;
  uint public constant PRICE_STAGE_FOUR = 300000;
  uint public constant PRICE_BTCS = 400000;
  //GUP Token Limits
  uint public constant MAX_SUPPLY =        100000000000;
  uint public constant ALLOC_ILLIQUID_TEAM = 8000000000;
  uint public constant ALLOC_LIQUID_TEAM =  13000000000;
  uint public constant ALLOC_BOUNTIES =      2000000000;
  uint public constant ALLOC_NEW_USERS =    17000000000;
  uint public constant ALLOC_CROWDSALE =    60000000000;
  uint public constant BTCS_PORTION_MAX = 37500 * PRICE_BTCS;
  //ASSIGNED IN INITIALIZATION
  //Start and end times
  uint public publicStartTime = 1490446800; //Time in seconds public crowd fund starts.
  uint public privateStartTime = 1490432400; //Time in seconds when BTCSuisse can purchase up to 125000 ETH worth of GUP;
  uint public publicEndTime; //Time in seconds crowdsale ends
  //Special Addresses
  address public btcsAddress = 0x00a88EDaA9eAd00A1d114e4820B0B0f2e3651ECE; //Address used by BTCSuisse
  address public multisigAddress = 0x2CAfdC32aC9eC55e915716bC43037Bd2C689512E; //Address to which all ether flows.
  address public matchpoolAddress = 0x00ce633b4789D1a16a0aD3AEC58599B76d5D669E; //Address to which ALLOC_BOUNTIES, ALLOC_LIQUID_TEAM, ALLOC_NEW_USERS, ALLOC_ILLIQUID_TEAM is sent to.
  address public ownerAddress = 0x00ce633b4789D1a16a0aD3AEC58599B76d5D669E; //Address of the contract owner. Can halt the crowdsale.
  //Contracts
  GUPToken public gupToken; //External token contract hollding the GUP
  //Running totals
  uint public etherRaised; //Total Ether raised.
  uint public gupSold; //Total GUP created
  uint public btcsPortionTotal; //Total of Tokens purchased by BTC Suisse. Not to exceed BTCS_PORTION_MAX.
  //booleans
  bool public halted; //halts the crowd sale if true.

  //FUNCTION MODIFIERS

  //Is currently in the period after the private start time and before the public start time.
  modifier is_pre_crowdfund_period() {
    if (now >= publicStartTime || now < privateStartTime) throw;
    _;
  }

  //Is currently the crowdfund period
  modifier is_crowdfund_period() {
    if (now < publicStartTime || now >= publicEndTime) throw;
    _;
  }

  //May only be called by BTC Suisse
  modifier only_btcs() {
    if (msg.sender != btcsAddress) throw;
    _;
  }

  //May only be called by the owner address
  modifier only_owner() {
    if (msg.sender != ownerAddress) throw;
    _;
  }

  //May only be called if the crowdfund has not been halted
  modifier is_not_halted() {
    if (halted) throw;
    _;
  }

  // EVENTS

  event PreBuy(uint _amount);
  event Buy(address indexed _recipient, uint _amount);


  // FUNCTIONS

  //Initialization function. Deploys GUPToken contract assigns values, to all remaining fields, creates first entitlements in the GUP Token contract.
  function Contribution() {
    publicEndTime = publicStartTime + STAGE_FOUR_TIME_END;
    gupToken = new GUPToken(this, publicEndTime);
    gupToken.createIlliquidToken(matchpoolAddress, ALLOC_ILLIQUID_TEAM);
    gupToken.createToken(matchpoolAddress, ALLOC_BOUNTIES);
    gupToken.createToken(matchpoolAddress, ALLOC_LIQUID_TEAM);
    gupToken.createToken(matchpoolAddress, ALLOC_NEW_USERS);
  }

  //May be used by owner of contract to halt crowdsale and no longer except ether.
  function toggleHalt(bool _halted)
    only_owner
  {
    halted = _halted;
  }

  //constant function returns the current GUP price.
  function getPriceRate()
    constant
    returns (uint o_rate)
  {
    if (now <= publicStartTime + STAGE_ONE_TIME_END) return PRICE_STAGE_ONE;
    if (now <= publicStartTime + STAGE_TWO_TIME_END) return PRICE_STAGE_TWO;
    if (now <= publicStartTime + STAGE_THREE_TIME_END) return PRICE_STAGE_THREE;
    if (now <= publicStartTime + STAGE_FOUR_TIME_END) return PRICE_STAGE_FOUR;
    else return 0;
  }

  // Given the rate of a purchase and the remaining tokens in this tranche, it
  // will throw if the sale would take it past the limit of the tranche.
  // It executes the purchase for the appropriate amount of tokens, which
  // involves adding it to the total, minting GUP tokens and stashing the
  // ether.
  // Returns `amount` in scope as the number of GUP tokens that it will
  // purchase.
  function processPurchase(uint _rate, uint _remaining)
    internal
    returns (uint o_amount)
  {
    o_amount = safeDiv(safeMul(msg.value, _rate), 1 ether);
    if (o_amount > _remaining) throw;
    if (!multisigAddress.send(msg.value)) throw;
    if (!gupToken.createToken(msg.sender, o_amount)) throw; //change to match create token
    gupSold += o_amount;
  }

  //Special Function can only be called by BTC Suisse and only during the pre-crowdsale period.
  //Allows the purchase of up to 125000 Ether worth of GUP Tokens.
  function preBuy()
    payable
    is_pre_crowdfund_period
    only_btcs
    is_not_halted
  {
    uint amount = processPurchase(PRICE_BTCS, BTCS_PORTION_MAX - btcsPortionTotal);
    btcsPortionTotal += amount;
    PreBuy(amount);
  }

  //Default function called by sending Ether to this address with no arguments.
  //Results in creation of new GUP Tokens if transaction would not exceed hard limit of GUP Token.
  function()
    payable
    is_crowdfund_period
    is_not_halted
  {
    uint amount = processPurchase(getPriceRate(), ALLOC_CROWDSALE - gupSold);
    Buy(msg.sender, amount);
  }

  //failsafe drain
  function drain()
    only_owner
  {
    if (!ownerAddress.send(this.balance)) throw;
  }
}