pragma solidity ^0.5.0;

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
	struct Role {
		mapping (address => bool) bearer;
	}

	/**
	 * @dev Give an account access to this role.
	 */
	function add(Role storage role, address account) internal {
		require(!has(role, account), "Roles: account already has role");
		role.bearer[account] = true;
	}

	/**
	 * @dev Remove an account's access to this role.
	 */
	function remove(Role storage role, address account) internal {
		require(has(role, account), "Roles: account does not have role");
		role.bearer[account] = false;
	}

	/**
	 * @dev Check if an account has this role.
	 * @return bool
	 */
	function has(Role storage role, address account) internal view returns (bool) {
		require(account != address(0), "Roles: account is the zero address");
		return role.bearer[account];
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/utils/ReentrancyGuard.sol

pragma solidity ^0.5.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 *
 * _Since v2.5.0:_ this module is now much more gas efficient, given net gas
 * metering changes introduced in the Istanbul hardfork.
 */
contract ReentrancyGuard {
	bool private _notEntered;

	constructor () internal {
		// Storing an initial non-zero value makes deployment a bit more
		// expensive, but in exchange the refund on every call to nonReentrant
		// will be lower in amount. Since refunds are capped to a percetange of
		// the total transaction's gas, it is best to keep them low in cases
		// like this one, to increase the likelihood of the full refund coming
		// into effect.
		_notEntered = true;
	}

	/**
	 * @dev Prevents a contract from calling itself, directly or indirectly.
	 * Calling a `nonReentrant` function from another `nonReentrant`
	 * function is not supported. It is possible to prevent this from happening
	 * by making the `nonReentrant` function external, and make it call a
	 * `private` function that does the actual work.
	 */
	modifier nonReentrant() {
		// On the first call to nonReentrant, _notEntered will be true
		require(_notEntered, "ReentrancyGuard: reentrant call");

		// Any calls to nonReentrant after this point will fail
		_notEntered = false;

		_;

		// By storing the original value once again, a refund is triggered (see
		// https://eips.ethereum.org/EIPS/eip-2200)
		_notEntered = true;
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
	/**
	 * @dev Returns true if `account` is a contract.
	 *
	 * [IMPORTANT]
	 * ====
	 * It is unsafe to assume that an address for which this function returns
	 * false is an externally-owned account (EOA) and not a contract.
	 *
	 * Among others, `isContract` will return false for the following 
	 * types of addresses:
	 *
	 *  - an externally-owned account
	 *  - a contract in construction
	 *  - an address where a contract will be created
	 *  - an address where a contract lived, but was destroyed
	 * ====
	 */
	function isContract(address account) internal view returns (bool) {
		// According to EIP-1052, 0x0 is the value returned for not-yet created accounts
		// and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
		// for accounts without code, i.e. `keccak256('')`
		bytes32 codehash;
		bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
		// solhint-disable-next-line no-inline-assembly
		assembly { codehash := extcodehash(account) }
		return (codehash != accountHash && codehash != 0x0);
	}

	/**
	 * @dev Converts an `address` into `address payable`. Note that this is
	 * simply a type cast: the actual underlying value is not changed.
	 *
	 * _Available since v2.4.0._
	 */
	function toPayable(address account) internal pure returns (address payable) {
		return address(uint160(account));
	}

	/**
	 * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
	 * `recipient`, forwarding all available gas and reverting on errors.
	 *
	 * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
	 * of certain opcodes, possibly making contracts go over the 2300 gas limit
	 * imposed by `transfer`, making them unable to receive funds via
	 * `transfer`. {sendValue} removes this limitation.
	 *
	 * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
	 *
	 * IMPORTANT: because control is transferred to `recipient`, care must be
	 * taken to not create reentrancy vulnerabilities. Consider using
	 * {ReentrancyGuard} or the
	 * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
	 *
	 * _Available since v2.4.0._
	 */
	function sendValue(address payable recipient, uint256 amount) internal {
		require(address(this).balance >= amount, "Address: insufficient balance");

		// solhint-disable-next-line avoid-call-value
		(bool success, ) = recipient.call.value(amount)("");
		require(success, "Address: unable to send value, recipient may have reverted");
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
	/**
	 * @dev Returns the amount of tokens in existence.
	 */
	function totalSupply() external view returns (uint256);

	/**
	 * @dev Returns the amount of tokens owned by `account`.
	 */
	function balanceOf(address account) external view returns (uint256);

	/**
	 * @dev Moves `amount` tokens from the caller's account to `recipient`.
	 *
	 * Returns a boolean value indicating whether the operation succeeded.
	 *
	 * Emits a {Transfer} event.
	 */
	function transfer(address recipient, uint256 amount) external returns (bool);

	/**
	 * @dev Returns the remaining number of tokens that `spender` will be
	 * allowed to spend on behalf of `owner` through {transferFrom}. This is
	 * zero by default.
	 *
	 * This value changes when {approve} or {transferFrom} are called.
	 */
	function allowance(address owner, address spender) external view returns (uint256);

	/**
	 * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
	 *
	 * Returns a boolean value indicating whether the operation succeeded.
	 *
	 * IMPORTANT: 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
	 *
	 * Emits an {Approval} event.
	 */
	function approve(address spender, uint256 amount) external returns (bool);

	/**
	 * @dev Moves `amount` tokens from `sender` to `recipient` using the
	 * allowance mechanism. `amount` is then deducted from the caller's
	 * allowance.
	 *
	 * Returns a boolean value indicating whether the operation succeeded.
	 *
	 * Emits a {Transfer} event.
	 */
	function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

	/**
	 * @dev Emitted when `value` tokens are moved from one account (`from`) to
	 * another (`to`).
	 *
	 * Note that `value` may be zero.
	 */
	event Transfer(address indexed from, address indexed to, uint256 value);

	/**
	 * @dev Emitted when the allowance of a `spender` for an `owner` is set by
	 * a call to {approve}. `value` is the new allowance.
	 */
	event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/GSN/Context.sol

pragma solidity ^0.5.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context {
	// Empty internal constructor, to prevent people from mistakenly deploying
	// an instance of this contract, which should be used via inheritance.
	constructor () internal { }
	// solhint-disable-previous-line no-empty-blocks

	function _msgSender() internal view returns (address payable) {
		return msg.sender;
	}

	function _msgData() internal view returns (bytes memory) {
		this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
		return msg.data;
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/ownership/Ownable.sol

pragma solidity ^0.5.0;

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
	address private _owner;

	event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

	/**
	 * @dev Initializes the contract setting the deployer as the initial owner.
	 */
	constructor () internal {
		address msgSender = _msgSender();
		_owner = msgSender;
		emit OwnershipTransferred(address(0), msgSender);
	}

	/**
	 * @dev Returns the address of the current owner.
	 */
	function owner() public view returns (address) {
		return _owner;
	}

	/**
	 * @dev Throws if called by any account other than the owner.
	 */
	modifier onlyOwner() {
		require(isOwner(), "Ownable: caller is not the owner");
		_;
	}

	/**
	 * @dev Returns true if the caller is the current owner.
	 */
	function isOwner() public view returns (bool) {
		return _msgSender() == _owner;
	}

	/**
	 * @dev Leaves the contract without owner. It will not be possible to call
	 * `onlyOwner` functions anymore. Can only be called by the current owner.
	 *
	 * NOTE: Renouncing ownership will leave the contract without an owner,
	 * thereby removing any functionality that is only available to the owner.
	 */
	function renounceOwnership() public onlyOwner {
		emit OwnershipTransferred(_owner, address(0));
		_owner = address(0);
	}

	/**
	 * @dev Transfers ownership of the contract to a new account (`newOwner`).
	 * Can only be called by the current owner.
	 */
	function transferOwnership(address newOwner) public onlyOwner {
		_transferOwnership(newOwner);
	}

	/**
	 * @dev Transfers ownership of the contract to a new account (`newOwner`).
	 */
	function _transferOwnership(address newOwner) internal {
		require(newOwner != address(0), "Ownable: new owner is the zero address");
		emit OwnershipTransferred(_owner, newOwner);
		_owner = newOwner;
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/access/roles/PauserRole.sol

pragma solidity ^0.5.0;



contract PauserRole is Context {
	using Roles for Roles.Role;

	event PauserAdded(address indexed account);
	event PauserRemoved(address indexed account);

	Roles.Role private _pausers;

	constructor () internal {
		_addPauser(_msgSender());
	}

	modifier onlyPauser() {
		require(isPauser(_msgSender()), "PauserRole: caller does not have the Pauser role");
		_;
	}

	function isPauser(address account) public view returns (bool) {
		return _pausers.has(account);
	}

	function addPauser(address account) public onlyPauser {
		_addPauser(account);
	}

	function renouncePauser() public {
		_removePauser(_msgSender());
	}

	function _addPauser(address account) internal {
		_pausers.add(account);
		emit PauserAdded(account);
	}

	function _removePauser(address account) internal {
		_pausers.remove(account);
		emit PauserRemoved(account);
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/lifecycle/Pausable.sol

pragma solidity ^0.5.0;



/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
contract Pausable is Context, PauserRole {
	/**
	 * @dev Emitted when the pause is triggered by a pauser (`account`).
	 */
	event Paused(address account);

	/**
	 * @dev Emitted when the pause is lifted by a pauser (`account`).
	 */
	event Unpaused(address account);

	bool private _paused;

	/**
	 * @dev Initializes the contract in unpaused state. Assigns the Pauser role
	 * to the deployer.
	 */
	constructor () internal {
		_paused = false;
	}

	/**
	 * @dev Returns true if the contract is paused, and false otherwise.
	 */
	function paused() public view returns (bool) {
		return _paused;
	}

	/**
	 * @dev Modifier to make a function callable only when the contract is not paused.
	 */
	modifier whenNotPaused() {
		require(!_paused, "Pausable: paused");
		_;
	}

	/**
	 * @dev Modifier to make a function callable only when the contract is paused.
	 */
	modifier whenPaused() {
		require(_paused, "Pausable: not paused");
		_;
	}

	/**
	 * @dev Called by a pauser to pause, triggers stopped state.
	 */
	function pause() public onlyPauser whenNotPaused {
		_paused = true;
		emit Paused(_msgSender());
	}

	/**
	 * @dev Called by a pauser to unpause, returns to normal state.
	 */
	function unpause() public onlyPauser whenPaused {
		_paused = false;
		emit Unpaused(_msgSender());
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/ownership/Secondary.sol

pragma solidity ^0.5.0;

/**
 * @dev A Secondary contract can only be used by its primary account (the one that created it).
 */
contract Secondary is Context {
	address private _primary;

	/**
	 * @dev Emitted when the primary contract changes.
	 */
	event PrimaryTransferred(
			address recipient
			);

	/**
	 * @dev Sets the primary account to the one that is creating the Secondary contract.
	 */
	constructor () internal {
		address msgSender = _msgSender();
		_primary = msgSender;
		emit PrimaryTransferred(msgSender);
	}

	/**
	 * @dev Reverts if called from any account other than the primary.
	 */
	modifier onlyPrimary() {
		require(_msgSender() == _primary, "Secondary: caller is not the primary account");
		_;
	}

	/**
	 * @return the address of the primary.
	 */
	function primary() public view returns (address) {
		return _primary;
	}

	/**
	 * @dev Transfers contract to a new primary.
	 * @param recipient The address of new primary.
	 */
	function transferPrimary(address recipient) public onlyPrimary {
		require(recipient != address(0), "Secondary: new primary is the zero address");
		_primary = recipient;
		emit PrimaryTransferred(recipient);
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
	/**
	 * @dev Returns the addition of two unsigned integers, reverting on
	 * overflow.
	 *
	 * Counterpart to Solidity's `+` operator.
	 *
	 * Requirements:
	 * - Addition cannot overflow.
	 */
	function add(uint256 a, uint256 b) internal pure returns (uint256) {
		uint256 c = a + b;
		require(c >= a, "SafeMath: addition overflow");

		return c;
	}

	/**
	 * @dev Returns the subtraction of two unsigned integers, reverting on
	 * overflow (when the result is negative).
	 *
	 * Counterpart to Solidity's `-` operator.
	 *
	 * Requirements:
	 * - Subtraction cannot overflow.
	 */
	function sub(uint256 a, uint256 b) internal pure returns (uint256) {
		return sub(a, b, "SafeMath: subtraction overflow");
	}

	/**
	 * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
	 * overflow (when the result is negative).
	 *
	 * Counterpart to Solidity's `-` operator.
	 *
	 * Requirements:
	 * - Subtraction cannot overflow.
	 *
	 * _Available since v2.4.0._
	 */
	function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
		require(b <= a, errorMessage);
		uint256 c = a - b;

		return c;
	}

	/**
	 * @dev Returns the multiplication of two unsigned integers, reverting on
	 * overflow.
	 *
	 * Counterpart to Solidity's `*` operator.
	 *
	 * Requirements:
	 * - Multiplication cannot overflow.
	 */
	function mul(uint256 a, uint256 b) internal pure returns (uint256) {
		// Gas optimization: this is cheaper than requiring 'a' not being zero, but the
		// benefit is lost if 'b' is also tested.
		// See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
		if (a == 0) {
			return 0;
		}

		uint256 c = a * b;
		require(c / a == b, "SafeMath: multiplication overflow");

		return c;
	}

	/**
	 * @dev Returns the integer division of two unsigned integers. Reverts on
	 * division by zero. The result is rounded towards zero.
	 *
	 * Counterpart to Solidity's `/` operator. Note: this function uses a
	 * `revert` opcode (which leaves remaining gas untouched) while Solidity
	 * uses an invalid opcode to revert (consuming all remaining gas).
	 *
	 * Requirements:
	 * - The divisor cannot be zero.
	 */
	function div(uint256 a, uint256 b) internal pure returns (uint256) {
		return div(a, b, "SafeMath: division by zero");
	}

	/**
	 * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
	 * division by zero. The result is rounded towards zero.
	 *
	 * Counterpart to Solidity's `/` operator. Note: this function uses a
	 * `revert` opcode (which leaves remaining gas untouched) while Solidity
	 * uses an invalid opcode to revert (consuming all remaining gas).
	 *
	 * Requirements:
	 * - The divisor cannot be zero.
	 *
	 * _Available since v2.4.0._
	 */
	function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
		// Solidity only automatically asserts when dividing by 0
		require(b > 0, errorMessage);
		uint256 c = a / b;
		// assert(a == b * c + a % b); // There is no case in which this doesn't hold

		return c;
	}

	/**
	 * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
	 * Reverts when dividing by zero.
	 *
	 * Counterpart to Solidity's `%` operator. This function uses a `revert`
	 * opcode (which leaves remaining gas untouched) while Solidity uses an
	 * invalid opcode to revert (consuming all remaining gas).
	 *
	 * Requirements:
	 * - The divisor cannot be zero.
	 */
	function mod(uint256 a, uint256 b) internal pure returns (uint256) {
		return mod(a, b, "SafeMath: modulo by zero");
	}

	/**
	 * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
	 * Reverts with custom message when dividing by zero.
	 *
	 * Counterpart to Solidity's `%` operator. This function uses a `revert`
	 * opcode (which leaves remaining gas untouched) while Solidity uses an
	 * invalid opcode to revert (consuming all remaining gas).
	 *
	 * Requirements:
	 * - The divisor cannot be zero.
	 *
	 * _Available since v2.4.0._
	 */
	function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
		require(b != 0, errorMessage);
		return a % b;
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
	using SafeMath for uint256;
	using Address for address;

	function safeTransfer(IERC20 token, address to, uint256 value) internal {
		callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
	}

	function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
		callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
	}

	function safeApprove(IERC20 token, address spender, uint256 value) internal {
		// safeApprove should only be called when setting an initial allowance,
		// or when resetting it to zero. To increase and decrease it, use
		// 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
		// solhint-disable-next-line max-line-length
		require((value == 0) || (token.allowance(address(this), spender) == 0),
				"SafeERC20: approve from non-zero to non-zero allowance"
		       );
		callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
	}

	function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
		uint256 newAllowance = token.allowance(address(this), spender).add(value);
		callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
	}

	function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
		uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
		callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
	}

	/**
	 * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
	 * on the return value: the return value is optional (but if data is returned, it must not be false).
	 * @param token The token targeted by the call.
	 * @param data The call data (encoded using abi.encode or one of its variants).
	 */
	function callOptionalReturn(IERC20 token, bytes memory data) private {
		// We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
		// we're implementing it ourselves.

		// A Solidity high level call has three parts:
		//  1. The target address is checked to verify it contains contract code
		//  2. The call itself is made, and success asserted
		//  3. The return value is decoded, which in turn checks the size of the returned data.
		// solhint-disable-next-line max-line-length
		require(address(token).isContract(), "SafeERC20: call to non-contract");

		// solhint-disable-next-line avoid-low-level-calls
		(bool success, bytes memory returndata) = address(token).call(data);
		require(success, "SafeERC20: low-level call failed");

		if (returndata.length > 0) { // Return data is optional
			// solhint-disable-next-line max-line-length
			require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
		}
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/crowdsale/Crowdsale.sol

pragma solidity ^0.5.0;






/**
 * @title Crowdsale
 * @dev Crowdsale is a base contract for managing a token crowdsale,
 * allowing investors to purchase tokens with ether. This contract implements
 * such functionality in its most fundamental form and can be extended to provide additional
 * functionality and/or custom behavior.
 * The external interface represents the basic interface for purchasing tokens, and conforms
 * the base architecture for crowdsales. It is *not* intended to be modified / overridden.
 * The internal interface conforms the extensible and modifiable surface of crowdsales. Override
 * the methods to add functionality. Consider using 'super' where appropriate to concatenate
 * behavior.
 */
contract Crowdsale is Context, ReentrancyGuard {
	using SafeMath for uint256;
	using SafeERC20 for IERC20;

	// The token being sold
	IERC20 private _token;

	// Address where funds are collected
	address payable private _wallet;

	// How many token units a buyer gets per wei.
	// The rate is the conversion between wei and the smallest and indivisible token unit.
	// So, if you are using a rate of 1 with a ERC20Detailed token with 3 decimals called TOK
	// 1 wei will give you 1 unit, or 0.001 TOK.
	uint256 private _rate;

	// Amount of wei raised
	uint256 private _weiRaised;

	/**
	 * 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 TokensPurchased(address indexed purchaser, address indexed beneficiary, uint256 value, uint256 amount);

	/**
	 * @param rate Number of token units a buyer gets per wei
	 * @dev The rate is the conversion between wei and the smallest and indivisible
	 * token unit. So, if you are using a rate of 1 with a ERC20Detailed token
	 * with 3 decimals called TOK, 1 wei will give you 1 unit, or 0.001 TOK.
	 * @param wallet Address where collected funds will be forwarded to
	 * @param token Address of the token being sold
	 */
	constructor (uint256 rate, address payable wallet, IERC20 token) public {
		require(rate > 0, "Crowdsale: rate is 0");
		require(wallet != address(0), "Crowdsale: wallet is the zero address");
		require(address(token) != address(0), "Crowdsale: token is the zero address");

		_rate = rate;
		_wallet = wallet;
		_token = token;
	}

	/**
	 * @dev fallback function ***DO NOT OVERRIDE***
	 * Note that other contracts will transfer funds with a base gas stipend
	 * of 2300, which is not enough to call buyTokens. Consider calling
	 * buyTokens directly when purchasing tokens from a contract.
	 */
	function () external payable {
		buyTokens(_msgSender());
	}

	/**
	 * @return the token being sold.
	 */
	function token() public view returns (IERC20) {
		return _token;
	}

	/**
	 * @return the address where funds are collected.
	 */
	function wallet() public view returns (address payable) {
		return _wallet;
	}

	/**
	 * @return the number of token units a buyer gets per wei.
	 */
	function rate() public view returns (uint256) {
		return _rate;
	}

	/**
	 * @return the amount of wei raised.
	 */
	function weiRaised() public view returns (uint256) {
		return _weiRaised;
	}

	/**
	 * @dev low level token purchase ***DO NOT OVERRIDE***
	 * This function has a non-reentrancy guard, so it shouldn't be called by
	 * another `nonReentrant` function.
	 * @param beneficiary Recipient of the token purchase
	 */
	function buyTokens(address beneficiary) public nonReentrant payable {
		uint256 weiAmount = msg.value;
		_preValidatePurchase(beneficiary, weiAmount);

		// calculate token amount to be created
		uint256 tokens = _getTokenAmount(weiAmount);

		// update state
		_weiRaised = _weiRaised.add(weiAmount);

		_processPurchase(beneficiary, tokens);
		emit TokensPurchased(_msgSender(), beneficiary, weiAmount, tokens);

		_updatePurchasingState(beneficiary, weiAmount);

		_forwardFunds();
		_postValidatePurchase(beneficiary, weiAmount);
	}

	/**
	 * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
	 * Use `super` in contracts that inherit from Crowdsale to extend their validations.
	 * Example from CappedCrowdsale.sol's _preValidatePurchase method:
	 *     super._preValidatePurchase(beneficiary, weiAmount);
	 *     require(weiRaised().add(weiAmount) <= cap);
	 * @param beneficiary Address performing the token purchase
	 * @param weiAmount Value in wei involved in the purchase
	 */
	function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
		require(beneficiary != address(0), "Crowdsale: beneficiary is the zero address");
		require(weiAmount != 0, "Crowdsale: weiAmount is 0");
		this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
	}

	/**
	 * @dev Validation of an executed purchase. Observe state and use revert statements to undo rollback when valid
	 * conditions are not met.
	 * @param beneficiary Address performing the token purchase
	 * @param weiAmount Value in wei involved in the purchase
	 */
	function _postValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
		// solhint-disable-previous-line no-empty-blocks
	}

	/**
	 * @dev Source of tokens. Override this method to modify the way in which the crowdsale ultimately gets and sends
	 * its tokens.
	 * @param beneficiary Address performing the token purchase
	 * @param tokenAmount Number of tokens to be emitted
	 */
	function _deliverTokens(address beneficiary, uint256 tokenAmount) internal {
		_token.safeTransfer(beneficiary, tokenAmount);
	}

	/**
	 * @dev Executed when a purchase has been validated and is ready to be executed. Doesn't necessarily emit/send
	 * tokens.
	 * @param beneficiary Address receiving the tokens
	 * @param tokenAmount Number of tokens to be purchased
	 */
	function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
		_deliverTokens(beneficiary, tokenAmount);
	}

	/**
	 * @dev Override for extensions that require an internal state to check for validity (current user contributions,
	 * etc.)
	 * @param beneficiary Address receiving the tokens
	 * @param weiAmount Value in wei involved in the purchase
	 */
	function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
		// solhint-disable-previous-line no-empty-blocks
	}

	/**
	 * @dev Override to extend the way in which ether is converted to tokens.
	 * @param weiAmount Value in wei to be converted into tokens
	 * @return Number of tokens that can be purchased with the specified _weiAmount
	 */
	function _getTokenAmount(uint256 weiAmount) internal view returns (uint256) {
		return weiAmount.mul(_rate);
	}

	/**
	 * @dev Determines how ETH is stored/forwarded on purchases.
	 */
	function _forwardFunds() internal {
		_wallet.transfer(msg.value);
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/crowdsale/validation/CappedCrowdsale.sol

pragma solidity ^0.5.0;



/**
 * @title CappedCrowdsale
 * @dev Crowdsale with a limit for total contributions.
 */
contract CappedCrowdsale is Crowdsale {
	using SafeMath for uint256;

	uint256 private _cap;

	/**
	 * @dev Constructor, takes maximum amount of wei accepted in the crowdsale.
	 * @param cap Max amount of wei to be contributed
	 */
	constructor (uint256 cap) public {
		require(cap > 0, "CappedCrowdsale: cap is 0");
		_cap = cap;
	}

	/**
	 * @return the cap of the crowdsale.
	 */
	function cap() public view returns (uint256) {
		return _cap;
	}

	/**
	 * @dev Checks whether the cap has been reached.
	 * @return Whether the cap was reached
	 */
	function capReached() public view returns (bool) {
		return weiRaised() >= _cap;
	}

	/**
	 * @dev Extend parent behavior requiring purchase to respect the funding cap.
	 * @param beneficiary Token purchaser
	 * @param weiAmount Amount of wei contributed
	 */
	function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
		super._preValidatePurchase(beneficiary, weiAmount);
		require(weiRaised().add(weiAmount) <= _cap, "CappedCrowdsale: cap exceeded");
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/crowdsale/validation/PausableCrowdsale.sol

pragma solidity ^0.5.0;



/**
 * @title PausableCrowdsale
 * @dev Extension of Crowdsale contract where purchases can be paused and unpaused by the pauser role.
 */
contract PausableCrowdsale is Crowdsale, Pausable {
	/**
	 * @dev Validation of an incoming purchase. Use require statements to revert state when conditions are not met.
	 * Use super to concatenate validations.
	 * Adds the validation that the crowdsale must not be paused.
	 * @param _beneficiary Address performing the token purchase
	 * @param _weiAmount Value in wei involved in the purchase
	 */
	function _preValidatePurchase(address _beneficiary, uint256 _weiAmount) internal view whenNotPaused {
		return super._preValidatePurchase(_beneficiary, _weiAmount);
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/crowdsale/validation/TimedCrowdsale.sol

pragma solidity ^0.5.0;



/**
 * @title TimedCrowdsale
 * @dev Crowdsale accepting contributions only within a time frame.
 */
contract TimedCrowdsale is Crowdsale {
	using SafeMath for uint256;

	// EDIT: changed from private to internal
	uint256 internal _openingTime;
	uint256 internal _closingTime;

	/**
	 * Event for crowdsale extending
	 * @param newClosingTime new closing time
	 * @param prevClosingTime old closing time
	 */
	event TimedCrowdsaleExtended(uint256 prevClosingTime, uint256 newClosingTime);

	/**
	 * @dev Reverts if not in crowdsale time range.
	 */
	modifier onlyWhileOpen {
		require(isOpen(), "TimedCrowdsale: not open");
		_;
	}

	/**
	 * @dev Constructor, takes crowdsale opening and closing times.
	 * @param openingTime Crowdsale opening time
	 * @param closingTime Crowdsale closing time
	 */
	constructor (uint256 openingTime, uint256 closingTime) public {
		// EDIT: removed requirement to open in future
		// solhint-disable-next-line not-rely-on-time
		// require(openingTime >= block.timestamp, "TimedCrowdsale: opening time is before current time");
		// solhint-disable-next-line max-line-length
		require(closingTime > openingTime, "TimedCrowdsale: opening time is not before closing time");

		_openingTime = openingTime;
		_closingTime = closingTime;
	}

	/**
	 * @return the crowdsale opening time.
	 */
	function openingTime() public view returns (uint256) {
		return _openingTime;
	}

	/**
	 * @return the crowdsale closing time.
	 */
	function closingTime() public view returns (uint256) {
		return _closingTime;
	}

	/**
	 * @return true if the crowdsale is open, false otherwise.
	 */
	function isOpen() public view returns (bool) {
		// solhint-disable-next-line not-rely-on-time
		return block.timestamp >= _openingTime && block.timestamp <= _closingTime;
	}

	/**
	 * @dev Checks whether the period in which the crowdsale is open has already elapsed.
	 * @return Whether crowdsale period has elapsed
	 */
	function hasClosed() public view returns (bool) {
		// solhint-disable-next-line not-rely-on-time
		return block.timestamp > _closingTime;
	}

	/**
	 * @dev Extend parent behavior requiring to be within contributing period.
	 * @param beneficiary Token purchaser
	 * @param weiAmount Amount of wei contributed
	 */
	function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal onlyWhileOpen view {
		super._preValidatePurchase(beneficiary, weiAmount);
	}

	/**
	 * @dev Extend crowdsale.
	 * @param newClosingTime Crowdsale closing time
	 */
	function _extendTime(uint256 newClosingTime) internal {
		require(!hasClosed(), "TimedCrowdsale: already closed");
		// solhint-disable-next-line max-line-length
		require(newClosingTime > _closingTime, "TimedCrowdsale: new closing time is before current closing time");

		emit TimedCrowdsaleExtended(_closingTime, newClosingTime);
		_closingTime = newClosingTime;
	}
}

// File: https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol

pragma solidity ^0.5.0;





/**
 * @title PostDeliveryCrowdsale
 * @dev Crowdsale that locks tokens from withdrawal until it ends.
 */
contract PostDeliveryCrowdsale is TimedCrowdsale {
	using SafeMath for uint256;

	mapping(address => uint256) private _balances;
	__unstable__TokenVault private _vault;

	constructor() public {
		_vault = new __unstable__TokenVault();
	}

	/**
	 * @dev Withdraw tokens only after crowdsale ends.
	 * @param beneficiary Whose tokens will be withdrawn.
	 */
	function withdrawTokens(address beneficiary) public {
		require(hasClosed(), "PostDeliveryCrowdsale: not closed");
		uint256 amount = _balances[beneficiary];
		require(amount > 0, "PostDeliveryCrowdsale: beneficiary is not due any tokens");

		_balances[beneficiary] = 0;
		_vault.transfer(token(), beneficiary, amount);
	}

	/**
	 * @return the balance of an account.
	 */
	function balanceOf(address account) public view returns (uint256) {
		return _balances[account];
	}

	/**
	 * @dev Overrides parent by storing due balances, and delivering tokens to the vault instead of the end user. This
	 * ensures that the tokens will be available by the time they are withdrawn (which may not be the case if
	 * `_deliverTokens` was called later).
	 * @param beneficiary Token purchaser
	 * @param tokenAmount Amount of tokens purchased
	 */
	function _processPurchase(address beneficiary, uint256 tokenAmount) internal {
		_balances[beneficiary] = _balances[beneficiary].add(tokenAmount);
		_deliverTokens(address(_vault), tokenAmount);
	}
}

/**
 * @title __unstable__TokenVault
 * @dev Similar to an Escrow for tokens, this contract allows its primary account to spend its tokens as it sees fit.
 * This contract is an internal helper for PostDeliveryCrowdsale, and should not be used outside of this context.
 */
// solhint-disable-next-line contract-name-camelcase
contract __unstable__TokenVault is Secondary {
	function transfer(IERC20 token, address to, uint256 amount) public onlyPrimary {
		token.transfer(to, amount);
	}
}

// File: contracts/CapPurchases.sol

pragma solidity ^0.5.0;

contract CapPurchases is Crowdsale {
	uint256 public contributionCap;
	mapping(address => uint256) private _contributions;

	constructor(uint256 cap) public {
		contributionCap = cap;
	}

	// override this to add a personal cap
	function _preValidatePurchase(address beneficiary, uint256 weiAmount) internal view {
		super._preValidatePurchase(beneficiary, weiAmount);
		// solhint-disable-next-line max-line-length
		require(_contributions[beneficiary].add(weiAmount) <= contributionCap, "personal cap exceeded");
	}

	// override this to track contributions
	function _updatePurchasingState(address beneficiary, uint256 weiAmount) internal {
		super._updatePurchasingState(beneficiary, weiAmount);
		_contributions[beneficiary] = _contributions[beneficiary].add(weiAmount);
	}
}


// File: contracts/presale.sol

pragma solidity ^0.5.0;


contract Presale is Crowdsale, TimedCrowdsale, PostDeliveryCrowdsale, Ownable, PausableCrowdsale, CapPurchases  {


	constructor(
			uint256 rate,            // rate, in TKNbits
			address payable wallet,  // wallet to send Ether
			IERC20 token,            // the token
			uint256 openingTime,     // opening time in unix epoch seconds
			uint256 closingTime      // closing time in unix epoch seconds
		   )
		public
		PostDeliveryCrowdsale()
		TimedCrowdsale(openingTime, closingTime)
		CapPurchases(100 * 1e18)
		Crowdsale(rate, wallet, token)   
		{
			// nice! this Crowdsale will keep all of the tokens until the end of the crowdsale
			// and then users can `withdrawTokens()` to get the tokens they're owed
		}

	function extend(uint256 _closing) public onlyOwner() {
		_extendTime(_closing);
	}

	function updateTimers(uint256 _opening, uint256 _closing) public onlyOwner() {
		require(_closing > _opening, "closeing time must be greater than closing time");
		_openingTime = _opening;
		_closingTime = _closing;
	}

	function openPresale() public onlyOwner() {
		_openingTime = block.timestamp;
	}

	function closePresale() public onlyOwner() {
		_closingTime = block.timestamp;
	}

	function freeTrappedEther(uint256 _withdraw) public onlyOwner() {
		msg.sender.transfer(_withdraw);
	}

	function reclaimUnsoldTokens(uint256 amount) public onlyOwner() {
		// sold coins are held int the token vault. and cannot be withdrawn
		token().transfer(msg.sender, amount);
	}


	/*********************/
	/*** for promotion ***/
	/*********************/

	mapping(address => uint256) promotion_map;
	address[] promoter_list;

	function getPromoterList() external view returns (address[] memory) {

		address[] memory r = new address[](promoter_list.length);
		for (uint256 i = 0; i < promoter_list.length; i++) {
			r[i] = promoter_list[i];
		}

		return r;
	}

	function getPromoterCounter(address promoter_address) public view returns(uint256) {
		return promotion_map[promoter_address];
	}

	function buTokenByRecommendation(address promoter_address) payable public {

		if (promotion_map[promoter_address] == 0) { // new promoter
			// add to promoter list
			promoter_list.push(promoter_address);
		}

		// calculate token amount to be created
                uint256 tokens = _getTokenAmount(msg.value);

		promotion_map[promoter_address] += tokens;

		buyTokens(msg.sender);
	}
}