Contract Name:
ProphetPool
Contract Source Code:
File 1 of 1 : ProphetPool
// Dependency file: @chainlink/contracts/src/v0.6/vendor/SafeMathChainlink.sol
// SPDX-License-Identifier: MIT
// pragma solidity ^0.6.0;
/**
* @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 SafeMathChainlink {
/**
* @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) {
require(b <= a, "SafeMath: subtraction overflow");
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-solidity/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) {
// Solidity only automatically asserts when dividing by 0
require(b > 0, "SafeMath: division by zero");
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) {
require(b != 0, "SafeMath: modulo by zero");
return a % b;
}
}
// Dependency file: @chainlink/contracts/src/v0.6/interfaces/LinkTokenInterface.sol
// pragma solidity ^0.6.0;
interface LinkTokenInterface {
function allowance(address owner, address spender) external view returns (uint256 remaining);
function approve(address spender, uint256 value) external returns (bool success);
function balanceOf(address owner) external view returns (uint256 balance);
function decimals() external view returns (uint8 decimalPlaces);
function decreaseApproval(address spender, uint256 addedValue) external returns (bool success);
function increaseApproval(address spender, uint256 subtractedValue) external;
function name() external view returns (string memory tokenName);
function symbol() external view returns (string memory tokenSymbol);
function totalSupply() external view returns (uint256 totalTokensIssued);
function transfer(address to, uint256 value) external returns (bool success);
function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool success);
function transferFrom(address from, address to, uint256 value) external returns (bool success);
}
// Dependency file: @chainlink/contracts/src/v0.6/VRFRequestIDBase.sol
// pragma solidity ^0.6.0;
contract VRFRequestIDBase {
/**
* @notice returns the seed which is actually input to the VRF coordinator
*
* @dev To prevent repetition of VRF output due to repetition of the
* @dev user-supplied seed, that seed is combined in a hash with the
* @dev user-specific nonce, and the address of the consuming contract. The
* @dev risk of repetition is mostly mitigated by inclusion of a blockhash in
* @dev the final seed, but the nonce does protect against repetition in
* @dev requests which are included in a single block.
*
* @param _userSeed VRF seed input provided by user
* @param _requester Address of the requesting contract
* @param _nonce User-specific nonce at the time of the request
*/
function makeVRFInputSeed(bytes32 _keyHash, uint256 _userSeed,
address _requester, uint256 _nonce)
internal pure returns (uint256)
{
return uint256(keccak256(abi.encode(_keyHash, _userSeed, _requester, _nonce)));
}
/**
* @notice Returns the id for this request
* @param _keyHash The serviceAgreement ID to be used for this request
* @param _vRFInputSeed The seed to be passed directly to the VRF
* @return The id for this request
*
* @dev Note that _vRFInputSeed is not the seed passed by the consuming
* @dev contract, but the one generated by makeVRFInputSeed
*/
function makeRequestId(
bytes32 _keyHash, uint256 _vRFInputSeed) internal pure returns (bytes32) {
return keccak256(abi.encodePacked(_keyHash, _vRFInputSeed));
}
}
// Dependency file: @chainlink/contracts/src/v0.6/VRFConsumerBase.sol
// pragma solidity ^0.6.0;
// import "@chainlink/contracts/src/v0.6/vendor/SafeMathChainlink.sol";
// import "@chainlink/contracts/src/v0.6/interfaces/LinkTokenInterface.sol";
// import "@chainlink/contracts/src/v0.6/VRFRequestIDBase.sol";
/** ****************************************************************************
* @notice Interface for contracts using VRF randomness
* *****************************************************************************
* @dev PURPOSE
*
* @dev Reggie the Random Oracle (not his real job) wants to provide randomness
* @dev to Vera the verifier in such a way that Vera can be sure he's not
* @dev making his output up to suit himself. Reggie provides Vera a public key
* @dev to which he knows the secret key. Each time Vera provides a seed to
* @dev Reggie, he gives back a value which is computed completely
* @dev deterministically from the seed and the secret key.
*
* @dev Reggie provides a proof by which Vera can verify that the output was
* @dev correctly computed once Reggie tells it to her, but without that proof,
* @dev the output is indistinguishable to her from a uniform random sample
* @dev from the output space.
*
* @dev The purpose of this contract is to make it easy for unrelated contracts
* @dev to talk to Vera the verifier about the work Reggie is doing, to provide
* @dev simple access to a verifiable source of randomness.
* *****************************************************************************
* @dev USAGE
*
* @dev Calling contracts must inherit from VRFConsumerBase, and can
* @dev initialize VRFConsumerBase's attributes in their constructor as
* @dev shown:
*
* @dev contract VRFConsumer {
* @dev constuctor(<other arguments>, address _vrfCoordinator, address _link)
* @dev VRFConsumerBase(_vrfCoordinator, _link) public {
* @dev <initialization with other arguments goes here>
* @dev }
* @dev }
*
* @dev The oracle will have given you an ID for the VRF keypair they have
* @dev committed to (let's call it keyHash), and have told you the minimum LINK
* @dev price for VRF service. Make sure your contract has sufficient LINK, and
* @dev call requestRandomness(keyHash, fee, seed), where seed is the input you
* @dev want to generate randomness from.
*
* @dev Once the VRFCoordinator has received and validated the oracle's response
* @dev to your request, it will call your contract's fulfillRandomness method.
*
* @dev The randomness argument to fulfillRandomness is the actual random value
* @dev generated from your seed.
*
* @dev The requestId argument is generated from the keyHash and the seed by
* @dev makeRequestId(keyHash, seed). If your contract could have concurrent
* @dev requests open, you can use the requestId to track which seed is
* @dev associated with which randomness. See VRFRequestIDBase.sol for more
* @dev details. (See "SECURITY CONSIDERATIONS" for principles to keep in mind,
* @dev if your contract could have multiple requests in flight simultaneously.)
*
* @dev Colliding `requestId`s are cryptographically impossible as long as seeds
* @dev differ. (Which is critical to making unpredictable randomness! See the
* @dev next section.)
*
* *****************************************************************************
* @dev SECURITY CONSIDERATIONS
*
* @dev A method with the ability to call your fulfillRandomness method directly
* @dev could spoof a VRF response with any random value, so it's critical that
* @dev it cannot be directly called by anything other than this base contract
* @dev (specifically, by the VRFConsumerBase.rawFulfillRandomness method).
*
* @dev For your users to trust that your contract's random behavior is free
* @dev from malicious interference, it's best if you can write it so that all
* @dev behaviors implied by a VRF response are executed *during* your
* @dev fulfillRandomness method. If your contract must store the response (or
* @dev anything derived from it) and use it later, you must ensure that any
* @dev user-significant behavior which depends on that stored value cannot be
* @dev manipulated by a subsequent VRF request.
*
* @dev Similarly, both miners and the VRF oracle itself have some influence
* @dev over the order in which VRF responses appear on the blockchain, so if
* @dev your contract could have multiple VRF requests in flight simultaneously,
* @dev you must ensure that the order in which the VRF responses arrive cannot
* @dev be used to manipulate your contract's user-significant behavior.
*
* @dev Since the ultimate input to the VRF is mixed with the block hash of the
* @dev block in which the request is made, user-provided seeds have no impact
* @dev on its economic security properties. They are only included for API
* @dev compatability with previous versions of this contract.
*
* @dev Since the block hash of the block which contains the requestRandomness
* @dev call is mixed into the input to the VRF *last*, a sufficiently powerful
* @dev miner could, in principle, fork the blockchain to evict the block
* @dev containing the request, forcing the request to be included in a
* @dev different block with a different hash, and therefore a different input
* @dev to the VRF. However, such an attack would incur a substantial economic
* @dev cost. This cost scales with the number of blocks the VRF oracle waits
* @dev until it calls responds to a request.
*/
abstract contract VRFConsumerBase is VRFRequestIDBase {
using SafeMathChainlink for uint256;
/**
* @notice fulfillRandomness handles the VRF response. Your contract must
* @notice implement it. See "SECURITY CONSIDERATIONS" above for important
* @notice principles to keep in mind when implementing your fulfillRandomness
* @notice method.
*
* @dev VRFConsumerBase expects its subcontracts to have a method with this
* @dev signature, and will call it once it has verified the proof
* @dev associated with the randomness. (It is triggered via a call to
* @dev rawFulfillRandomness, below.)
*
* @param requestId The Id initially returned by requestRandomness
* @param randomness the VRF output
*/
function fulfillRandomness(bytes32 requestId, uint256 randomness)
internal virtual;
/**
* @notice requestRandomness initiates a request for VRF output given _seed
*
* @dev The fulfillRandomness method receives the output, once it's provided
* @dev by the Oracle, and verified by the vrfCoordinator.
*
* @dev The _keyHash must already be registered with the VRFCoordinator, and
* @dev the _fee must exceed the fee specified during registration of the
* @dev _keyHash.
*
* @dev The _seed parameter is vestigial, and is kept only for API
* @dev compatibility with older versions. It can't *hurt* to mix in some of
* @dev your own randomness, here, but it's not necessary because the VRF
* @dev oracle will mix the hash of the block containing your request into the
* @dev VRF seed it ultimately uses.
*
* @param _keyHash ID of public key against which randomness is generated
* @param _fee The amount of LINK to send with the request
* @param _seed seed mixed into the input of the VRF.
*
* @return requestId unique ID for this request
*
* @dev The returned requestId can be used to distinguish responses to
* @dev concurrent requests. It is passed as the first argument to
* @dev fulfillRandomness.
*/
function requestRandomness(bytes32 _keyHash, uint256 _fee, uint256 _seed)
internal returns (bytes32 requestId)
{
LINK.transferAndCall(vrfCoordinator, _fee, abi.encode(_keyHash, _seed));
// This is the seed passed to VRFCoordinator. The oracle will mix this with
// the hash of the block containing this request to obtain the seed/input
// which is finally passed to the VRF cryptographic machinery.
uint256 vRFSeed = makeVRFInputSeed(_keyHash, _seed, address(this), nonces[_keyHash]);
// nonces[_keyHash] must stay in sync with
// VRFCoordinator.nonces[_keyHash][this], which was incremented by the above
// successful LINK.transferAndCall (in VRFCoordinator.randomnessRequest).
// This provides protection against the user repeating their input seed,
// which would result in a predictable/duplicate output, if multiple such
// requests appeared in the same block.
nonces[_keyHash] = nonces[_keyHash].add(1);
return makeRequestId(_keyHash, vRFSeed);
}
LinkTokenInterface immutable internal LINK;
address immutable private vrfCoordinator;
// Nonces for each VRF key from which randomness has been requested.
//
// Must stay in sync with VRFCoordinator[_keyHash][this]
mapping(bytes32 /* keyHash */ => uint256 /* nonce */) private nonces;
/**
* @param _vrfCoordinator address of VRFCoordinator contract
* @param _link address of LINK token contract
*
* @dev https://docs.chain.link/docs/link-token-contracts
*/
constructor(address _vrfCoordinator, address _link) public {
vrfCoordinator = _vrfCoordinator;
LINK = LinkTokenInterface(_link);
}
// rawFulfillRandomness is called by VRFCoordinator when it receives a valid VRF
// proof. rawFulfillRandomness then calls fulfillRandomness, after validating
// the origin of the call
function rawFulfillRandomness(bytes32 requestId, uint256 randomness) external {
require(msg.sender == vrfCoordinator, "Only VRFCoordinator can fulfill");
fulfillRandomness(requestId, randomness);
}
}
// Dependency file: @openzeppelin/contracts/token/ERC20/IERC20.sol
// pragma solidity ^0.6.0;
/**
* @dev Interface of the ERC20 standard as defined in the EIP.
*/
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);
}
// Dependency file: @openzeppelin/contracts/utils/Address.sol
// pragma solidity ^0.6.2;
/**
* @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 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].
*/
function sendValue(address payable recipient, uint256 amount) internal {
require(address(this).balance >= amount, "Address: insufficient balance");
// solhint-disable-next-line avoid-low-level-calls, avoid-call-value
(bool success, ) = recipient.call{ value: amount }("");
require(success, "Address: unable to send value, recipient may have reverted");
}
/**
* @dev Performs a Solidity function call using a low level `call`. A
* plain`call` is an unsafe replacement for a function call: use this
* function instead.
*
* If `target` reverts with a revert reason, it is bubbled up by this
* function (like regular Solidity function calls).
*
* Returns the raw returned data. To convert to the expected return value,
* use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
*
* Requirements:
*
* - `target` must be a contract.
* - calling `target` with `data` must not revert.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data) internal returns (bytes memory) {
return functionCall(target, data, "Address: low-level call failed");
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
* `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
return _functionCallWithValue(target, data, 0, errorMessage);
}
/**
* @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
* but also transferring `value` wei to `target`.
*
* Requirements:
*
* - the calling contract must have an ETH balance of at least `value`.
* - the called Solidity function must be `payable`.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
}
/**
* @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
* with `errorMessage` as a fallback revert reason when `target` reverts.
*
* _Available since v3.1._
*/
function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
require(address(this).balance >= value, "Address: insufficient balance for call");
return _functionCallWithValue(target, data, value, errorMessage);
}
function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
require(isContract(target), "Address: call to non-contract");
// solhint-disable-next-line avoid-low-level-calls
(bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
if (success) {
return returndata;
} else {
// Look for revert reason and bubble it up if present
if (returndata.length > 0) {
// The easiest way to bubble the revert reason is using memory via assembly
// solhint-disable-next-line no-inline-assembly
assembly {
let returndata_size := mload(returndata)
revert(add(32, returndata), returndata_size)
}
} else {
revert(errorMessage);
}
}
}
}
// Dependency file: @openzeppelin/contracts/utils/ReentrancyGuard.sol
// pragma solidity ^0.6.0;
/**
* @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].
*/
contract ReentrancyGuard {
// Booleans are more expensive than uint256 or any type that takes up a full
// word because each write operation emits an extra SLOAD to first read the
// slot's contents, replace the bits taken up by the boolean, and then write
// back. This is the compiler's defense against contract upgrades and
// pointer aliasing, and it cannot be disabled.
// The values being 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 percentage 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.
uint256 private constant _NOT_ENTERED = 1;
uint256 private constant _ENTERED = 2;
uint256 private _status;
constructor () internal {
_status = _NOT_ENTERED;
}
/**
* @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(_status != _ENTERED, "ReentrancyGuard: reentrant call");
// Any calls to nonReentrant after this point will fail
_status = _ENTERED;
_;
// By storing the original value once again, a refund is triggered (see
// https://eips.ethereum.org/EIPS/eip-2200)
_status = _NOT_ENTERED;
}
}
// Dependency file: @openzeppelin/contracts/GSN/Context.sol
// pragma solidity ^0.6.0;
/*
* @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.
*/
abstract contract Context {
function _msgSender() internal view virtual returns (address payable) {
return msg.sender;
}
function _msgData() internal view virtual returns (bytes memory) {
this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
return msg.data;
}
}
// Dependency file: @openzeppelin/contracts/access/Ownable.sol
// pragma solidity ^0.6.0;
// import "@openzeppelin/contracts/GSN/Context.sol";
/**
* @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.
*
* By default, the owner account will be the one that deploys the contract. This
* can later be changed with {transferOwnership}.
*
* 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(_owner == _msgSender(), "Ownable: caller is not the 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 virtual 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 virtual onlyOwner {
require(newOwner != address(0), "Ownable: new owner is the zero address");
emit OwnershipTransferred(_owner, newOwner);
_owner = newOwner;
}
}
// Dependency file: contracts/lib/Uint256ArrayUtils.sol
// pragma solidity 0.6.10;
/**
* @title Uint256ArrayUtils
* @author Prophecy
*
* Utility functions to handle uint256 Arrays
*/
library Uint256ArrayUtils {
/**
* Finds the index of the first occurrence of the given element.
* @param A The input array to search
* @param a The value to find
* @return Returns (index and isIn) for the first occurrence starting from index 0
*/
function indexOf(uint256[] memory A, uint256 a) internal pure returns (uint256, bool) {
uint256 length = A.length;
for (uint256 i = 0; i < length; i++) {
if (A[i] == a) {
return (i, true);
}
}
return (uint256(-1), false);
}
/**
* Returns true if the value is present in the list. Uses indexOf internally.
* @param A The input array to search
* @param a The value to find
* @return Returns isIn for the first occurrence starting from index 0
*/
function contains(uint256[] memory A, uint256 a) internal pure returns (bool) {
(, bool isIn) = indexOf(A, a);
return isIn;
}
/**
* Returns true if there are 2 elements that are the same in an array
* @param A The input array to search
* @return Returns boolean for the first occurrence of a duplicate
*/
function hasDuplicate(uint256[] memory A) internal pure returns(bool) {
require(A.length > 0, "A is empty");
for (uint256 i = 0; i < A.length - 1; i++) {
uint256 current = A[i];
for (uint256 j = i + 1; j < A.length; j++) {
if (current == A[j]) {
return true;
}
}
}
return false;
}
/**
* @param A The input array to search
* @param a The uint256 to remove
* @return Returns the array with the object removed.
*/
function remove(uint256[] memory A, uint256 a)
internal
pure
returns (uint256[] memory)
{
(uint256 index, bool isIn) = indexOf(A, a);
if (!isIn) {
revert("uint256 not in array.");
} else {
(uint256[] memory _A,) = pop(A, index);
return _A;
}
}
/**
* @param A The input array to search
* @param a The uint256 to remove
*/
function removeStorage(uint256[] storage A, uint256 a)
internal
{
(uint256 index, bool isIn) = indexOf(A, a);
if (!isIn) {
revert("uint256 not in array.");
} else {
uint256 lastIndex = A.length - 1; // If the array would be empty, the previous line would throw, so no underflow here
if (index != lastIndex) { A[index] = A[lastIndex]; }
A.pop();
}
}
/**
* Removes specified index from array
* @param A The input array to search
* @param index The index to remove
* @return Returns the new array and the removed entry
*/
function pop(uint256[] memory A, uint256 index)
internal
pure
returns (uint256[] memory, uint256)
{
uint256 length = A.length;
require(index < A.length, "Index must be < A length");
uint256[] memory newUint256s = new uint256[](length - 1);
for (uint256 i = 0; i < index; i++) {
newUint256s[i] = A[i];
}
for (uint256 j = index + 1; j < length; j++) {
newUint256s[j - 1] = A[j];
}
return (newUint256s, A[index]);
}
/**
* Returns the combination of the two arrays
* @param A The first array
* @param B The second array
* @return Returns A extended by B
*/
function extend(uint256[] memory A, uint256[] memory B) internal pure returns (uint256[] memory) {
uint256 aLength = A.length;
uint256 bLength = B.length;
uint256[] memory newUint256s = new uint256[](aLength + bLength);
for (uint256 i = 0; i < aLength; i++) {
newUint256s[i] = A[i];
}
for (uint256 j = 0; j < bLength; j++) {
newUint256s[aLength + j] = B[j];
}
return newUint256s;
}
/**
* Validate uint256 array is not empty and contains no duplicate elements.
*
* @param A Array of uint256
*/
function _validateLengthAndUniqueness(uint256[] memory A) internal pure {
require(A.length > 0, "Array length must be > 0");
require(!hasDuplicate(A), "Cannot duplicate uint256");
}
}
// Dependency file: contracts/lib/AddressArrayUtils.sol
// pragma solidity 0.6.10;
/**
* @title AddressArrayUtils
* @author Prophecy
*
* Utility functions to handle uint256 Arrays
*/
library AddressArrayUtils {
/**
* Finds the index of the first occurrence of the given element.
* @param A The input array to search
* @param a The value to find
* @return Returns (index and isIn) for the first occurrence starting from index 0
*/
function indexOf(address[] memory A, address a) internal pure returns (uint256, bool) {
uint256 length = A.length;
for (uint256 i = 0; i < length; i++) {
if (A[i] == a) {
return (i, true);
}
}
return (uint256(-1), false);
}
/**
* Returns true if the value is present in the list. Uses indexOf internally.
* @param A The input array to search
* @param a The value to find
* @return Returns isIn for the first occurrence starting from index 0
*/
function contains(address[] memory A, address a) internal pure returns (bool) {
(, bool isIn) = indexOf(A, a);
return isIn;
}
/**
* Returns true if there are 2 elements that are the same in an array
* @param A The input array to search
* @return Returns boolean for the first occurrence of a duplicate
*/
function hasDuplicate(address[] memory A) internal pure returns(bool) {
require(A.length > 0, "A is empty");
for (uint256 i = 0; i < A.length - 1; i++) {
address current = A[i];
for (uint256 j = i + 1; j < A.length; j++) {
if (current == A[j]) {
return true;
}
}
}
return false;
}
/**
* @param A The input array to search
* @param a The address to remove
* @return Returns the array with the object removed.
*/
function remove(address[] memory A, address a)
internal
pure
returns (address[] memory)
{
(uint256 index, bool isIn) = indexOf(A, a);
if (!isIn) {
revert("Address not in array.");
} else {
(address[] memory _A,) = pop(A, index);
return _A;
}
}
/**
* @param A The input array to search
* @param a The address to remove
*/
function removeStorage(address[] storage A, address a)
internal
{
(uint256 index, bool isIn) = indexOf(A, a);
if (!isIn) {
revert("Address not in array.");
} else {
uint256 lastIndex = A.length - 1; // If the array would be empty, the previous line would throw, so no underflow here
if (index != lastIndex) { A[index] = A[lastIndex]; }
A.pop();
}
}
/**
* Removes specified index from array
* @param A The input array to search
* @param index The index to remove
* @return Returns the new array and the removed entry
*/
function pop(address[] memory A, uint256 index)
internal
pure
returns (address[] memory, address)
{
uint256 length = A.length;
require(index < A.length, "Index must be < A length");
address[] memory newAddresses = new address[](length - 1);
for (uint256 i = 0; i < index; i++) {
newAddresses[i] = A[i];
}
for (uint256 j = index + 1; j < length; j++) {
newAddresses[j - 1] = A[j];
}
return (newAddresses, A[index]);
}
/**
* Returns the combination of the two arrays
* @param A The first array
* @param B The second array
* @return Returns A extended by B
*/
function extend(address[] memory A, address[] memory B) internal pure returns (address[] memory) {
uint256 aLength = A.length;
uint256 bLength = B.length;
address[] memory newAddresses = new address[](aLength + bLength);
for (uint256 i = 0; i < aLength; i++) {
newAddresses[i] = A[i];
}
for (uint256 j = 0; j < bLength; j++) {
newAddresses[aLength + j] = B[j];
}
return newAddresses;
}
/**
* Validate that address and uint array lengths match. Validate address array is not empty
* and contains no duplicate elements.
*
* @param A Array of addresses
* @param B Array of uint
*/
function validatePairsWithArray(address[] memory A, uint[] memory B) internal pure {
require(A.length == B.length, "Array length mismatch");
_validateLengthAndUniqueness(A);
}
/**
* Validate that address and bool array lengths match. Validate address array is not empty
* and contains no duplicate elements.
*
* @param A Array of addresses
* @param B Array of bool
*/
function validatePairsWithArray(address[] memory A, bool[] memory B) internal pure {
require(A.length == B.length, "Array length mismatch");
_validateLengthAndUniqueness(A);
}
/**
* Validate that address and string array lengths match. Validate address array is not empty
* and contains no duplicate elements.
*
* @param A Array of addresses
* @param B Array of strings
*/
function validatePairsWithArray(address[] memory A, string[] memory B) internal pure {
require(A.length == B.length, "Array length mismatch");
_validateLengthAndUniqueness(A);
}
/**
* Validate that address array lengths match, and calling address array are not empty
* and contain no duplicate elements.
*
* @param A Array of addresses
* @param B Array of addresses
*/
function validatePairsWithArray(address[] memory A, address[] memory B) internal pure {
require(A.length == B.length, "Array length mismatch");
_validateLengthAndUniqueness(A);
}
/**
* Validate that address and bytes array lengths match. Validate address array is not empty
* and contains no duplicate elements.
*
* @param A Array of addresses
* @param B Array of bytes
*/
function validatePairsWithArray(address[] memory A, bytes[] memory B) internal pure {
require(A.length == B.length, "Array length mismatch");
_validateLengthAndUniqueness(A);
}
/**
* Validate address array is not empty and contains no duplicate elements.
*
* @param A Array of addresses
*/
function _validateLengthAndUniqueness(address[] memory A) internal pure {
require(A.length > 0, "Array length must be > 0");
require(!hasDuplicate(A), "Cannot duplicate addresses");
}
}
// Dependency file: contracts/interfaces/IWETH.sol
// pragma solidity 0.6.10;
// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
/**
* @title IWETH
* @author Prophecy
*
* Interface for Wrapped Ether. This interface allows for interaction for wrapped ether's deposit and withdrawal
* functionality.
*/
interface IWETH is IERC20{
function deposit() external payable;
function withdraw(uint256 wad) external;
}
// Dependency file: contracts/interfaces/IProphetPoolFactory.sol
// pragma solidity ^0.6.10;
/**
* @title IProphetPoolFactory
* @author Prophecy
*/
interface IProphetPoolFactory {
/**
* Creates a ProphetPool smart contract set the manager(owner) of the pool.
*/
function create(string memory, address, address, address) external returns (address);
/**
* Return WETH address.
*/
function getWeth() external view returns (address);
/**
* Return VRF Key Hash.
*/
function getVrfKeyHash() external view returns (bytes32);
/**
* Return VRF Fee.
*/
function getVrfFee() external view returns (uint256);
/**
* Return Link Token address for VRF.
*/
function getLinkToken() external view returns (address);
/**
* Return VRF coordinator.
*/
function getVrfCoordinator() external view returns (address);
/**
* Return all pools addreses
*/
function getAllPools() external view returns (address[] memory);
}
// Root file: contracts/ProphetPool.sol
pragma solidity ^0.6.10;
pragma experimental ABIEncoderV2;
// import { VRFConsumerBase } from "@chainlink/contracts/src/v0.6/VRFConsumerBase.sol";
// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
// import { Address } from "@openzeppelin/contracts/utils/Address.sol";
// import { ReentrancyGuard } from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
// import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
// import { Uint256ArrayUtils } from "contracts/lib/Uint256ArrayUtils.sol";
// import { AddressArrayUtils } from "contracts/lib/AddressArrayUtils.sol";
// import { IWETH } from "contracts/interfaces/IWETH.sol";
// import { IProphetPoolFactory } from "contracts/interfaces/IProphetPoolFactory.sol";
/**
* @title ProphetPool
* @author Prophecy
*
* Smart contract that facilitates that draws lucky winners in the pool and distribut rewards to the winners.
*/
contract ProphetPool is VRFConsumerBase, ReentrancyGuard, Ownable {
using Address for address;
using Uint256ArrayUtils for uint256[];
using AddressArrayUtils for address[];
/* ============ Structs ============ */
struct PoolConfig {
uint256 numOfWinners;
uint256 participantLimit;
uint256 enterAmount;
uint256 feePercentage;
uint256 randomSeed;
uint256 startedAt;
}
/* ============ Enums ============ */
enum PoolStatus { NOTSTARTED, INPROGRESS, CLOSED }
/* ============ Events ============ */
event FeeRecipientSet(address indexed _feeRecipient);
event MaxParticipationCompleted(address indexed _from);
event RandomNumberGenerated(uint256 indexed randomness);
event WinnersGenerated(uint256[] winnerIndexes);
event PoolSettled();
event PoolStarted(
uint256 participantLimit,
uint256 numOfWinners,
uint256 enterAmount,
uint256 feePercentage,
uint256 startedAt
);
event PoolReset();
event EnteredPool(address indexed _participant, uint256 _amount, uint256 indexed _participantIndex);
/* ============ State Variables ============ */
IProphetPoolFactory private factory;
address private feeRecipient;
string private poolName;
IERC20 private enterToken;
PoolStatus private poolStatus;
PoolConfig private poolConfig;
address[] private participants;
uint256[] private winnerIndexes;
uint256 private totalEnteredAmount;
uint256 private rewardPerParticipant;
uint256 internal randomResult;
bool internal areWinnersGenerated;
/* ============ Modifiers ============ */
modifier onlyValidPool() {
require(participants.length < poolConfig.participantLimit, "Max Participation for the Pool Reached");
require(poolStatus == PoolStatus.INPROGRESS, "The Pool is not started or closed");
_;
}
modifier onlyEOA() {
require(tx.origin == msg.sender, "Only EOA allowed");
_;
}
/* ============ Constructor ============ */
/**
* Create the ProphetPool with Chainlink VRF configuration for Random number generation.
*
* @param _poolName Pool name
* @param _enterToken ERC20 token to enter the pool. If it's ETH pool, it should be WETH address
* @param _factory ProphetPoolFactory
* @param _feeRecipient Where the fee go
*/
constructor(
string memory _poolName,
address _enterToken,
address _factory,
address _feeRecipient
)
public
VRFConsumerBase(IProphetPoolFactory(_factory).getVrfCoordinator(), IProphetPoolFactory(_factory).getLinkToken())
{
poolName = _poolName;
enterToken = IERC20(_enterToken);
factory = IProphetPoolFactory(_factory);
feeRecipient = _feeRecipient;
poolStatus = PoolStatus.NOTSTARTED;
}
/* ============ External/Public Functions ============ */
/**
* Set the Pool Config, initializes an instance of and start the pool.
*
* @param _numOfWinners Number of winners in the pool
* @param _participantLimit Maximum number of paricipants
* @param _enterAmount Exact amount to enter this pool
* @param _feePercentage Manager fee of this pool
* @param _randomSeed Seed for Random Number Generation
*/
function setPoolRules(
uint256 _numOfWinners,
uint256 _participantLimit,
uint256 _enterAmount,
uint256 _feePercentage,
uint256 _randomSeed
) external onlyOwner {
require(poolStatus == PoolStatus.NOTSTARTED, "A Pool is in progress");
require(_numOfWinners != 0, "Number of winner must not be 0");
require(_numOfWinners < _participantLimit, "Too much number of winners");
poolConfig = PoolConfig(
_numOfWinners,
_participantLimit,
_enterAmount,
_feePercentage,
_randomSeed,
block.timestamp
);
poolStatus = PoolStatus.INPROGRESS;
emit PoolStarted(
_participantLimit,
_numOfWinners,
_enterAmount,
_feePercentage,
block.timestamp
);
}
/**
* Set the Pool Config, initializes an instance of and start the pool.
*
* @param _feeRecipient Number of winners in the pool
*/
function setFeeRecipient(address _feeRecipient) external onlyOwner {
require(_feeRecipient != address(0), "Invalid address");
feeRecipient = _feeRecipient;
emit FeeRecipientSet(feeRecipient);
}
/**
* Enter pool with ETH
*/
function enterPoolEth() external payable onlyValidPool onlyEOA returns (uint256) {
require(msg.value == poolConfig.enterAmount, "Insufficent registration amount provided");
if (!_isEthPool()) {
revert("ETH isn't accepted");
}
// wrap ETH to WETH
IWETH(factory.getWeth()).deposit{ value: msg.value }();
return _enterPool();
}
/**
* Enter pool with ERC20 token
*/
function enterPool() external onlyValidPool onlyEOA returns (uint256) {
enterToken.transferFrom(
msg.sender,
address(this),
poolConfig.enterAmount
);
return _enterPool();
}
/**
* Settle the pool, the winners are selected randomly and fee is transfer to the manager.
*/
function settlePool() external {
require(randomResult > 0, "RND in progress");
require(poolStatus == PoolStatus.INPROGRESS, "The Pool is in progress");
// generate winnerIndexes until the numOfWinners reach
uint256 newRandom = randomResult;
uint256 offset = 0;
while(winnerIndexes.length < poolConfig.numOfWinners) {
uint256 winningIndex = newRandom.mod(poolConfig.participantLimit);
if (!winnerIndexes.contains(winningIndex)) {
winnerIndexes.push(winningIndex);
}
offset.add(1);
newRandom = _getRandomNumberBlockchain(offset, newRandom);
}
areWinnersGenerated = true;
emit WinnersGenerated(winnerIndexes);
// set pool CLOSED status
poolStatus = PoolStatus.CLOSED;
// transfer fees
uint256 feeAmount = totalEnteredAmount.mul(poolConfig.feePercentage).div(100);
rewardPerParticipant = (totalEnteredAmount.sub(feeAmount)).div(poolConfig.numOfWinners);
_transferEnterToken(feeRecipient, feeAmount);
// collectRewards();
emit PoolSettled();
}
/**
* The winners of the pool can call this function to transfer their winnings
* from the pool contract to their own address.
*/
function collectRewards() external nonReentrant {
require(poolStatus == PoolStatus.CLOSED, "The Pool is not settled.");
for (uint256 i = 0; i < poolConfig.participantLimit; i = i.add(1)) {
address player = participants[i];
if (winnerIndexes.contains(i)) {
// if winner
_transferEnterToken(player, rewardPerParticipant);
}
}
_resetPool();
}
/**
* The contract will receive Ether
*/
receive() external payable {}
/**
* Getter for factory
*/
function getFactory() external view returns (address) {
return address(factory);
}
/**
* Getter for fee recipient
*/
function getFeeRecipient() external view returns (address) {
return feeRecipient;
}
/**
* Getter for poolName
*/
function getPoolName() external view returns (string memory) {
return poolName;
}
/**
* Getter for enterToken
*/
function getEnterToken() external view returns (address) {
return address(enterToken);
}
/**
* Getter for poolStatus
*/
function getPoolStatus() external view returns (PoolStatus) {
return poolStatus;
}
/**
* Getter for poolConfig
*/
function getPoolConfig() external view returns (PoolConfig memory) {
return poolConfig;
}
/**
* Getter for totalEnteredAmount
*/
function getTotalEnteredAmount() external view returns (uint256) {
return totalEnteredAmount;
}
/**
* Getter for rewardPerParticipant
*/
function getRewardPerParticipant() external view returns (uint256) {
return rewardPerParticipant;
}
/**
* Get all participants
*/
function getParticipants() external view returns(address[] memory) {
return participants;
}
/**
* Get one participant by index
* @param _index Index of the participants array
*/
function getParticipant(uint256 _index) external view returns(address) {
return participants[_index];
}
/**
* Getter for winnerIndexes
*/
function getWinnerIndexes() external view returns(uint256[] memory) {
return winnerIndexes;
}
/**
* Get if the account is winner
*/
function isWinner(address _account) external view returns(bool) {
(uint256 index, bool isExist) = participants.indexOf(_account);
if (isExist) {
return winnerIndexes.contains(index);
} else {
return false;
}
}
/* ============ Private/Internal Functions ============ */
/**
* Participant enters the pool and enter amount is transferred from the user to the pool.
*/
function _enterPool() internal returns(uint256 _participantIndex) {
participants.push(msg.sender);
totalEnteredAmount = totalEnteredAmount.add(poolConfig.enterAmount);
if (participants.length == poolConfig.participantLimit) {
emit MaxParticipationCompleted(msg.sender);
_getRandomNumber(poolConfig.randomSeed);
}
_participantIndex = (participants.length).sub(1);
emit EnteredPool(msg.sender, poolConfig.enterAmount, _participantIndex);
}
/**
* Reset the pool, clears the existing state variable values and the pool can be initialized again.
*/
function _resetPool() internal {
poolStatus = PoolStatus.INPROGRESS;
delete totalEnteredAmount;
delete rewardPerParticipant;
randomResult = 0;
areWinnersGenerated = false;
delete winnerIndexes;
delete participants;
emit PoolReset();
uint256 tokenBalance = enterToken.balanceOf(address(this));
if (tokenBalance > 0) {
enterToken.transfer(feeRecipient, tokenBalance);
}
}
/**
* Transfer enterToken even it's ETH or ERC20.
*
* @param _to Offset to generate the random number
* @param _amount Random number to generate the other random number
*/
function _transferEnterToken(address _to, uint256 _amount) internal {
if (_isEthPool()) {
IWETH(factory.getWeth()).withdraw(_amount);
(bool status, ) = payable(_to).call{value: _amount}("");
require(status, "ETH not transferred");
} else {
enterToken.transfer(address(_to), _amount);
}
}
/**
* Check pool is ETH pool or not
*/
function _isEthPool() internal view returns (bool) {
return address(enterToken) == factory.getWeth();
}
/**
* Generate a random number based on the blockHash and random offset
*
* @param _offset Offset to generate the random number
* @param _randomness Random number to generate the other random number
*/
function _getRandomNumberBlockchain(uint256 _offset, uint256 _randomness)
internal
view
returns (uint256)
{
bytes32 baseHash = keccak256(
abi.encodePacked(
blockhash(block.number),
bytes32(_offset),
bytes32(_randomness)
)
);
return uint256(baseHash);
}
/**
* Calls ChainLink Oracle's inherited function for Random Number Generation.
* The contract must have enough LINK required for VRF.
*
* @param _userProvidedSeed Seed to generate the random number
*/
function _getRandomNumber(uint256 _userProvidedSeed)
internal
returns (bytes32 requestId)
{
require(
IERC20(factory.getLinkToken()).balanceOf(address(this)) >= factory.getVrfFee(),
"Not enough LINK for VRF"
);
randomResult = 0;
return
requestRandomness(
factory.getVrfKeyHash(),
factory.getVrfFee(),
_userProvidedSeed
);
}
/**
* Callback function used by VRF Coordinator.
*
* @param _randomness Generated random number
*/
function fulfillRandomness(bytes32, uint256 _randomness) internal override {
randomResult = _randomness;
emit RandomNumberGenerated(_randomness);
}
}