pragma solidity ^0.4.16;

contract Token {
    bytes32 public standard;
    bytes32 public name;
    bytes32 public symbol;
    uint256 public totalSupply;
    uint8 public decimals;
    bool public allowTransactions;
    mapping (address => uint256) public balanceOf;
    mapping (address => mapping (address => uint256)) public allowance;
    function transfer(address _to, uint256 _value) returns (bool success);
    function approveAndCall(address _spender, uint256 _value, bytes _extraData) returns (bool success);
    function approve(address _spender, uint256 _value) returns (bool success);
    function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
}

contract Exchange {
  function assert(bool assertion) {
    if (!assertion) throw;
  }
  function safeMul(uint a, uint b) returns (uint) {
    uint c = a * b;
    assert(a == 0 || c / a == b);
    return c;
  }

  function safeSub(uint a, uint b) returns (uint) {
    assert(b <= a);
    return a - b;
  }

  function safeAdd(uint a, uint b) returns (uint) {
    uint c = a + b;
    assert(c>=a && c>=b);
    return c;
  }
  address public owner;
  mapping (address => uint256) public invalidOrder;
  event SetOwner(address indexed previousOwner, address indexed newOwner);
  modifier onlyOwner {
    assert(msg.sender == owner);
    _;
  }
  function setOwner(address newOwner) onlyOwner {
    SetOwner(owner, newOwner);
    owner = newOwner;
  }
  function getOwner() returns (address out) {
    return owner;
  }
  function invalidateOrdersBefore(address user, uint256 nonce) onlyAdmin {
    if (nonce < invalidOrder[user]) throw;
    invalidOrder[user] = nonce;
  }

  mapping (address => mapping (address => uint256)) public tokens; //mapping of token addresses to mapping of account balances

  mapping (address => bool) public admins;
  mapping (address => uint256) public lastActiveTransaction;
  mapping (bytes32 => uint256) public orderFills;
  address public feeAccount;
  uint256 public inactivityReleasePeriod;
  mapping (bytes32 => bool) public traded;
  mapping (bytes32 => bool) public withdrawn;
  event Order(address tokenBuy, uint256 amountBuy, address tokenSell, uint256 amountSell, uint256 expires, uint256 nonce, address user, uint8 v, bytes32 r, bytes32 s);
  event Cancel(address tokenBuy, uint256 amountBuy, address tokenSell, uint256 amountSell, uint256 expires, uint256 nonce, address user, uint8 v, bytes32 r, bytes32 s);
  event Trade(address tokenBuy, uint256 amountBuy, address tokenSell, uint256 amountSell, address get, address give);
  event Deposit(address token, address user, uint256 amount, uint256 balance);
  event Withdraw(address token, address user, uint256 amount, uint256 balance);

  function setInactivityReleasePeriod(uint256 expiry) onlyAdmin returns (bool success) {
    if (expiry > 1000000) throw;
    inactivityReleasePeriod = expiry;
    return true;
  }

  function Exchange(address feeAccount_) {
    owner = msg.sender;
    feeAccount = feeAccount_;
    inactivityReleasePeriod = 100000;
  }

  function setAdmin(address admin, bool isAdmin) onlyOwner {
    admins[admin] = isAdmin;
  }

  modifier onlyAdmin {
    if (msg.sender != owner && !admins[msg.sender]) throw;
    _;
  }

  function() external {
    throw;
  }

  function depositToken(address token, uint256 amount) {
    tokens[token][msg.sender] = safeAdd(tokens[token][msg.sender], amount);
    lastActiveTransaction[msg.sender] = block.number;
    if (!Token(token).transferFrom(msg.sender, this, amount)) throw;
    Deposit(token, msg.sender, amount, tokens[token][msg.sender]);
  }

  function deposit() payable {
    tokens[address(0)][msg.sender] = safeAdd(tokens[address(0)][msg.sender], msg.value);
    lastActiveTransaction[msg.sender] = block.number;
    Deposit(address(0), msg.sender, msg.value, tokens[address(0)][msg.sender]);
  }

  function withdraw(address token, uint256 amount) returns (bool success) {
    if (safeSub(block.number, lastActiveTransaction[msg.sender]) < inactivityReleasePeriod) throw;
    if (tokens[token][msg.sender] < amount) throw;
    tokens[token][msg.sender] = safeSub(tokens[token][msg.sender], amount);
    if (token == address(0)) {
      if (!msg.sender.send(amount)) throw;
    } else {
      if (!Token(token).transfer(msg.sender, amount)) throw;
    }
    Withdraw(token, msg.sender, amount, tokens[token][msg.sender]);
  }

  function adminWithdraw(address token, uint256 amount, address user, uint256 nonce, uint8 v, bytes32 r, bytes32 s, uint256 feeWithdrawal) onlyAdmin returns (bool success) {
    bytes32 hash = keccak256(this, token, amount, user, nonce);
    if (withdrawn[hash]) throw;
    withdrawn[hash] = true;
    if (ecrecover(keccak256("\x19Ethereum Signed Message:\n32", hash), v, r, s) != user) throw;
    if (feeWithdrawal > 50 finney) feeWithdrawal = 50 finney;
    if (tokens[token][user] < amount) throw;
    tokens[token][user] = safeSub(tokens[token][user], amount);
    tokens[token][feeAccount] = safeAdd(tokens[token][feeAccount], safeMul(feeWithdrawal, amount) / 1 ether);
    amount = safeMul((1 ether - feeWithdrawal), amount) / 1 ether;
    if (token == address(0)) {
      if (!user.send(amount)) throw;
    } else {
      if (!Token(token).transfer(user, amount)) throw;
    }
    lastActiveTransaction[user] = block.number;
    Withdraw(token, user, amount, tokens[token][user]);
  }

  function balanceOf(address token, address user) constant returns (uint256) {
    return tokens[token][user];
  }

  function trade(uint256[8] tradeValues, address[4] tradeAddresses, uint8[2] v, bytes32[4] rs) onlyAdmin returns (bool success) {
    /* amount is in amountBuy terms */
    /* tradeValues
       [0] amountBuy
       [1] amountSell
       [2] expires
       [3] nonce
       [4] amount
       [5] tradeNonce
       [6] feeMake
       [7] feeTake
     tradeAddressses
       [0] tokenBuy
       [1] tokenSell
       [2] maker
       [3] taker
     */
    if (invalidOrder[tradeAddresses[2]] > tradeValues[3]) throw;
    bytes32 orderHash = keccak256(this, tradeAddresses[0], tradeValues[0], tradeAddresses[1], tradeValues[1], tradeValues[2], tradeValues[3], tradeAddresses[2]);
    if (ecrecover(keccak256("\x19Ethereum Signed Message:\n32", orderHash), v[0], rs[0], rs[1]) != tradeAddresses[2]) throw;
    bytes32 tradeHash = keccak256(orderHash, tradeValues[4], tradeAddresses[3], tradeValues[5]); 
    if (ecrecover(keccak256("\x19Ethereum Signed Message:\n32", tradeHash), v[1], rs[2], rs[3]) != tradeAddresses[3]) throw;
    if (traded[tradeHash]) throw;
    traded[tradeHash] = true;
    if (tradeValues[6] > 100 finney) tradeValues[6] = 100 finney;
    if (tradeValues[7] > 100 finney) tradeValues[7] = 100 finney;
    if (safeAdd(orderFills[orderHash], tradeValues[4]) > tradeValues[0]) throw;
    if (tokens[tradeAddresses[0]][tradeAddresses[3]] < tradeValues[4]) throw;
    if (tokens[tradeAddresses[1]][tradeAddresses[2]] < (safeMul(tradeValues[1], tradeValues[4]) / tradeValues[0])) throw;
    tokens[tradeAddresses[0]][tradeAddresses[3]] = safeSub(tokens[tradeAddresses[0]][tradeAddresses[3]], tradeValues[4]);
    tokens[tradeAddresses[0]][tradeAddresses[2]] = safeAdd(tokens[tradeAddresses[0]][tradeAddresses[2]], safeMul(tradeValues[4], ((1 ether) - tradeValues[6])) / (1 ether));
    tokens[tradeAddresses[0]][feeAccount] = safeAdd(tokens[tradeAddresses[0]][feeAccount], safeMul(tradeValues[4], tradeValues[6]) / (1 ether));
    tokens[tradeAddresses[1]][tradeAddresses[2]] = safeSub(tokens[tradeAddresses[1]][tradeAddresses[2]], safeMul(tradeValues[1], tradeValues[4]) / tradeValues[0]);
    tokens[tradeAddresses[1]][tradeAddresses[3]] = safeAdd(tokens[tradeAddresses[1]][tradeAddresses[3]], safeMul(safeMul(((1 ether) - tradeValues[7]), tradeValues[1]), tradeValues[4]) / tradeValues[0] / (1 ether));
    tokens[tradeAddresses[1]][feeAccount] = safeAdd(tokens[tradeAddresses[1]][feeAccount], safeMul(safeMul(tradeValues[7], tradeValues[1]), tradeValues[4]) / tradeValues[0] / (1 ether));
    orderFills[orderHash] = safeAdd(orderFills[orderHash], tradeValues[4]);
    lastActiveTransaction[tradeAddresses[2]] = block.number;
    lastActiveTransaction[tradeAddresses[3]] = block.number;
  }
}

pragma solidity 0.4.23;

//
// This source file is part of the current-contracts open source project
// Copyright 2018 Zerion LLC
// Licensed under Apache License v2.0
//


// @title Abstract ERC20 token interface
contract AbstractToken {
	function balanceOf(address owner) public view returns (uint256 balance);
	function transfer(address to, uint256 value) public returns (bool success);
	function transferFrom(address from, address to, uint256 value) public returns (bool success);
	function approve(address spender, uint256 value) public returns (bool success);
	function allowance(address owner, address spender) public view returns (uint256 remaining);

	event Transfer(address indexed from, address indexed to, uint256 value);
	event Approval(address indexed owner, address indexed spender, uint256 value);
}

contract Owned {

	address public owner = msg.sender;
	address public potentialOwner;

	modifier onlyOwner {
		require(msg.sender == owner);
		_;
	}

	modifier onlyPotentialOwner {
		require(msg.sender == potentialOwner);
		_;
	}

	event NewOwner(address old, address current);
	event NewPotentialOwner(address old, address potential);

	function setOwner(address _new)
		public
		onlyOwner
	{
		emit NewPotentialOwner(owner, _new);
		potentialOwner = _new;
	}

	function confirmOwnership()
		public
		onlyPotentialOwner
	{
		emit NewOwner(owner, potentialOwner);
		owner = potentialOwner;
		potentialOwner = address(0);
	}
}

// @title SafeMath contract - Math operations with safety checks.
// @author OpenZeppelin: https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/math/SafeMath.sol
contract SafeMath {
	/**
	* @dev Multiplies two numbers, throws on overflow.
	*/
	function mul(uint256 a, uint256 b) internal pure returns (uint256) {
		if (a == 0) {
			return 0;
		}
		uint256 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) {
		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) {
		uint256 c = a + b;
		assert(c >= a);
		return c;
	}

	/**
	* @dev Raises `a` to the `b`th power, throws on overflow.
	*/
	function pow(uint256 a, uint256 b) internal pure returns (uint256) {
		uint256 c = a ** b;
		assert(c >= a);
		return c;
	}
}

/// Implements ERC 20 Token standard: https://github.com/ethereum/EIPs/issues/20
contract StandardToken is AbstractToken, Owned, SafeMath {

	/*
	 *  Data structures
	 */
	mapping (address => uint256) internal balances;
	mapping (address => mapping (address => uint256)) internal allowed;
	uint256 public totalSupply;

	/*
	 *  Read and write storage functions
	 */
	/// @dev Transfers sender's tokens to a given address. Returns success.
	/// @param _to Address of token receiver.
	/// @param _value Number of tokens to transfer.
	function transfer(address _to, uint256 _value) public returns (bool success) {
		return _transfer(msg.sender, _to, _value);
	}

	/// @dev Allows allowed third party to transfer tokens from one address to another. Returns success.
	/// @param _from Address from where tokens are withdrawn.
	/// @param _to Address to where tokens are sent.
	/// @param _value Number of tokens to transfer.
	function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
		require(allowed[_from][msg.sender] >= _value);
		allowed[_from][msg.sender] -= _value;

		return _transfer(_from, _to, _value);
	}

	/// @dev Returns number of tokens owned by given address.
	/// @param _owner Address of token owner.
	function balanceOf(address _owner) public view returns (uint256 balance) {
		return balances[_owner];
	}

	/// @dev Sets approved amount of tokens for spender. Returns success.
	/// @param _spender Address of allowed account.
	/// @param _value Number of approved tokens.
	function approve(address _spender, uint256 _value) public returns (bool success) {
		allowed[msg.sender][_spender] = _value;
		emit Approval(msg.sender, _spender, _value);
		return true;
	}

	/*
	 * Read storage functions
	 */
	/// @dev Returns number of allowed tokens for given address.
	/// @param _owner Address of token owner.
	/// @param _spender Address of token spender.
	function allowance(address _owner, address _spender) public view returns (uint256 remaining) {
		return allowed[_owner][_spender];
	}

	/**
	* @dev Private transfer, can only be called by this contract.
	* @param _from The address of the sender.
	* @param _to The address of the recipient.
	* @param _value The amount to send.
	* @return success True if the transfer was successful, or throws.
	*/
	function _transfer(address _from, address _to, uint256 _value) private returns (bool success) {
		require(_to != address(0));
		require(balances[_from] >= _value);
		balances[_from] -= _value;
		balances[_to] = add(balances[_to], _value);
		emit Transfer(_from, _to, _value);
		return true;
	}
}

/// @title Token contract - Implements Standard ERC20 with additional features.
/// @author Zerion - <[email protected]>
contract Token is StandardToken {

	// Time of the contract creation
	uint256 public creationTime;

	function Token() public {
		/* solium-disable-next-line security/no-block-members */
		creationTime = now;
	}

	/// @dev Owner can transfer out any accidentally sent ERC20 tokens
	function transferERC20Token(AbstractToken _token, address _to, uint256 _value)
		public
		onlyOwner
		returns (bool success)
	{
		require(_token.balanceOf(address(this)) >= _value);
		uint256 receiverBalance = _token.balanceOf(_to);
		require(_token.transfer(_to, _value));

		uint256 receiverNewBalance = _token.balanceOf(_to);
		assert(receiverNewBalance == add(receiverBalance, _value));

		return true;
	}

	/// @dev Increases approved amount of tokens for spender. Returns success.
	function increaseApproval(address _spender, uint256 _value) public returns (bool success) {
		allowed[msg.sender][_spender] = add(allowed[msg.sender][_spender], _value);
		emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
		return true;
	}

	/// @dev Decreases approved amount of tokens for spender. Returns success.
	function decreaseApproval(address _spender, uint256 _value) public returns (bool success) {
		uint256 oldValue = allowed[msg.sender][_spender];
		if (_value > oldValue) {
			allowed[msg.sender][_spender] = 0;
		} else {
			allowed[msg.sender][_spender] = sub(oldValue, _value);
		}
		emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
		return true;
	}
}

// @title Token contract - Implements Standard ERC20 Token for NEXO project.
/// @author Zerion - <[email protected]>
contract NexoToken is Token {

	/// TOKEN META DATA
	string constant public name = 'Nexo';
	string constant public symbol = 'NEXO';
	uint8  constant public decimals = 18;


	/// ALOCATIONS
	// To calculate vesting periods we assume that 1 month is always equal to 30 days 


	/*** Initial Investors' tokens ***/

	// 525,000,000 (52.50%) tokens are distributed among initial investors
	// These tokens will be distributed without vesting

	address public investorsAllocation = address(0xFFfFfFffFFfffFFfFFfFFFFFffFFFffffFfFFFfF);
	uint256 public investorsTotal = 525000000e18;


	/*** Overdraft Reserves ***/

	// 250,000,000 (25%) tokens will be eventually available for overdraft
	// These tokens will be distributed monthly with a 6 month cliff within a year
	// 41,666,666 tokens will be unlocked every month after the cliff
	// 4 tokens will be unlocked without vesting to ensure that total amount sums up to 250,000,000.

	address public overdraftAllocation = address(0x1111111111111111111111111111111111111111);
	uint256 public overdraftTotal = 250000000e18;
	uint256 public overdraftPeriodAmount = 41666666e18;
	uint256 public overdraftUnvested = 4e18;
	uint256 public overdraftCliff = 5 * 30 days;
	uint256 public overdraftPeriodLength = 30 days;
	uint8   public overdraftPeriodsNumber = 6;


	/*** Tokens reserved for Founders and Team ***/

	// 112,500,000 (11.25%) tokens will be eventually available for the team
	// These tokens will be distributed every 3 month without a cliff within 4 years
	// 7,031,250 tokens will be unlocked every 3 month

	address public teamAllocation  = address(0x2222222222222222222222222222222222222222);
	uint256 public teamTotal = 112500000e18;
	uint256 public teamPeriodAmount = 7031250e18;
	uint256 public teamUnvested = 0;
	uint256 public teamCliff = 0;
	uint256 public teamPeriodLength = 3 * 30 days;
	uint8   public teamPeriodsNumber = 16;



	/*** Tokens reserved for Community Building and Airdrop Campaigns ***/

	// 60,000,000 (6%) tokens will be eventually available for the community
	// 10,000,002 tokens will be available instantly without vesting
	// 49,999,998 tokens will be distributed every 3 month without a cliff within 18 months
	// 8,333,333 tokens will be unlocked every 3 month


	address public communityAllocation  = address(0x3333333333333333333333333333333333333333);
	uint256 public communityTotal = 60000000e18;
	uint256 public communityPeriodAmount = 8333333e18;
	uint256 public communityUnvested = 10000002e18;
	uint256 public communityCliff = 0;
	uint256 public communityPeriodLength = 3 * 30 days;
	uint8   public communityPeriodsNumber = 6;



	/*** Tokens reserved for Advisors, Legal and PR ***/

	// 52,500,000 (5.25%) tokens will be eventually available for advisers
	// 25,000,008 tokens will be available instantly without vesting
	// 27 499 992 tokens will be distributed monthly without a cliff within 12 months
	// 2,291,666 tokens will be unlocked every month

	address public advisersAllocation  = address(0x4444444444444444444444444444444444444444);
	uint256 public advisersTotal = 52500000e18;
	uint256 public advisersPeriodAmount = 2291666e18;
	uint256 public advisersUnvested = 25000008e18;
	uint256 public advisersCliff = 0;
	uint256 public advisersPeriodLength = 30 days;
	uint8   public advisersPeriodsNumber = 12;


	/// CONSTRUCTOR

	function NexoToken() public {
		//  Overall, 1,000,000,000 tokens exist
		totalSupply = 1000000000e18;

		balances[investorsAllocation] = investorsTotal;
		balances[overdraftAllocation] = overdraftTotal;
		balances[teamAllocation] = teamTotal;
		balances[communityAllocation] = communityTotal;
		balances[advisersAllocation] = advisersTotal;

		// Unlock some tokens without vesting
		allowed[investorsAllocation][msg.sender] = investorsTotal;
		allowed[overdraftAllocation][msg.sender] = overdraftUnvested;
		allowed[communityAllocation][msg.sender] = communityUnvested;
		allowed[advisersAllocation][msg.sender] = advisersUnvested;
	}

	/// DISTRIBUTION

	function distributeInvestorsTokens(address _to, uint256 _amountWithDecimals)
		public
		onlyOwner
	{
		require(transferFrom(investorsAllocation, _to, _amountWithDecimals));
	}

	/// VESTING

	function withdrawOverdraftTokens(address _to, uint256 _amountWithDecimals)
		public
		onlyOwner
	{
		allowed[overdraftAllocation][msg.sender] = allowance(overdraftAllocation, msg.sender);
		require(transferFrom(overdraftAllocation, _to, _amountWithDecimals));
	}

	function withdrawTeamTokens(address _to, uint256 _amountWithDecimals)
		public
		onlyOwner 
	{
		allowed[teamAllocation][msg.sender] = allowance(teamAllocation, msg.sender);
		require(transferFrom(teamAllocation, _to, _amountWithDecimals));
	}

	function withdrawCommunityTokens(address _to, uint256 _amountWithDecimals)
		public
		onlyOwner 
	{
		allowed[communityAllocation][msg.sender] = allowance(communityAllocation, msg.sender);
		require(transferFrom(communityAllocation, _to, _amountWithDecimals));
	}

	function withdrawAdvisersTokens(address _to, uint256 _amountWithDecimals)
		public
		onlyOwner 
	{
		allowed[advisersAllocation][msg.sender] = allowance(advisersAllocation, msg.sender);
		require(transferFrom(advisersAllocation, _to, _amountWithDecimals));
	}

	/// @dev Overrides StandardToken.sol function
	function allowance(address _owner, address _spender)
		public
		view
		returns (uint256 remaining)
	{   
		if (_spender != owner) {
			return allowed[_owner][_spender];
		}

		uint256 unlockedTokens;
		uint256 spentTokens;

		if (_owner == overdraftAllocation) {
			unlockedTokens = _calculateUnlockedTokens(
				overdraftCliff,
				overdraftPeriodLength,
				overdraftPeriodAmount,
				overdraftPeriodsNumber,
				overdraftUnvested
			);
			spentTokens = sub(overdraftTotal, balanceOf(overdraftAllocation));
		} else if (_owner == teamAllocation) {
			unlockedTokens = _calculateUnlockedTokens(
				teamCliff,
				teamPeriodLength,
				teamPeriodAmount,
				teamPeriodsNumber,
				teamUnvested
			);
			spentTokens = sub(teamTotal, balanceOf(teamAllocation));
		} else if (_owner == communityAllocation) {
			unlockedTokens = _calculateUnlockedTokens(
				communityCliff,
				communityPeriodLength,
				communityPeriodAmount,
				communityPeriodsNumber,
				communityUnvested
			);
			spentTokens = sub(communityTotal, balanceOf(communityAllocation));
		} else if (_owner == advisersAllocation) {
			unlockedTokens = _calculateUnlockedTokens(
				advisersCliff,
				advisersPeriodLength,
				advisersPeriodAmount,
				advisersPeriodsNumber,
				advisersUnvested
			);
			spentTokens = sub(advisersTotal, balanceOf(advisersAllocation));
		} else {
			return allowed[_owner][_spender];
		}

		return sub(unlockedTokens, spentTokens);
	}

	/// @dev Overrides Owned.sol function
	function confirmOwnership()
		public
		onlyPotentialOwner
	{   
		// Forbid the old owner to distribute investors' tokens
		allowed[investorsAllocation][owner] = 0;

		// Allow the new owner to distribute investors' tokens
		allowed[investorsAllocation][msg.sender] = balanceOf(investorsAllocation);

		// Forbid the old owner to withdraw any tokens from the reserves
		allowed[overdraftAllocation][owner] = 0;
		allowed[teamAllocation][owner] = 0;
		allowed[communityAllocation][owner] = 0;
		allowed[advisersAllocation][owner] = 0;

		super.confirmOwnership();
	}

	function _calculateUnlockedTokens(
		uint256 _cliff,
		uint256 _periodLength,
		uint256 _periodAmount,
		uint8 _periodsNumber,
		uint256 _unvestedAmount
	)
		private
		view
		returns (uint256) 
	{
		/* solium-disable-next-line security/no-block-members */
		if (now < add(creationTime, _cliff)) {
			return _unvestedAmount;
		}
		/* solium-disable-next-line security/no-block-members */
		uint256 periods = div(sub(now, add(creationTime, _cliff)), _periodLength);
		periods = periods > _periodsNumber ? _periodsNumber : periods;
		return add(_unvestedAmount, mul(periods, _periodAmount));
	}
}