// File: @chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface AggregatorV3Interface {
  function decimals() external view returns (uint8);

  function description() external view returns (string memory);

  function version() external view returns (uint256);

  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );

  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/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.
 */
abstract 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() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/security/Pausable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @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.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @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].
 */
abstract 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() {
        _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 making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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);

    /**
     * @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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.sol";
import "../../../utils/Address.sol";

/**
 * @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 IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    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));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    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'
        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) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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. We use {Address-functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @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");

        (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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @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 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) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: contracts/PredictionMarket.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
pragma abicoder v2;

import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {Pausable} from "@openzeppelin/contracts/security/Pausable.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {AggregatorV3Interface} from "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

/**
 * @title Prediction Market Contract with ERC20 bets
 */
contract PredictionMarket is Ownable, Pausable, ReentrancyGuard {
    using SafeERC20 for IERC20;

    IERC20 public immutable token; // Prediction token

    AggregatorV3Interface public oracle;

    bool public genesisLockOnce = false;
    bool public genesisStartOnce = false;

    address public adminAddress; // address of the admin
    address public operatorAddress; // address of the operator

    uint256 public bufferSeconds; // number of seconds for valid execution of a prediction round
    uint256 public intervalSeconds; // interval in seconds between two prediction rounds

    uint256 public minBetAmount; // minimum betting amount (denominated in wei)
    uint256 public treasuryFee; // treasury rate (e.g. 200 = 2%, 150 = 1.50%)
    uint256 public treasuryAmount; // treasury amount that was not claimed

    uint256 public currentEpoch; // current epoch for prediction round

    uint256 public oracleLatestRoundId; // converted from uint80 (Chainlink)
    uint256 public oracleUpdateAllowance; // seconds

    uint256 public constant MAX_TREASURY_FEE = 1000; // 10%

    mapping(uint256 => mapping(address => BetInfo)) public ledger;
    mapping(uint256 => Round) public rounds;
    mapping(address => uint256[]) public userRounds;

    enum Position {
        Bull,
        Bear
    }

    struct Round {
        uint256 epoch;
        uint256 startTimestamp;
        uint256 lockTimestamp;
        uint256 closeTimestamp;
        int256 lockPrice;
        int256 closePrice;
        uint256 lockOracleId;
        uint256 closeOracleId;
        uint256 totalAmount;
        uint256 bullAmount;
        uint256 bearAmount;
        uint256 rewardBaseCalAmount;
        uint256 rewardAmount;
        bool oracleCalled;
    }

    struct BetInfo {
        Position position;
        uint256 amount;
        bool claimed; // default false
    }

    event BetBear(address indexed sender, uint256 indexed epoch, uint256 amount);
    event BetBull(address indexed sender, uint256 indexed epoch, uint256 amount);
    event Claim(address indexed sender, uint256 indexed epoch, uint256 amount);
    event EndRound(uint256 indexed epoch, uint256 indexed roundId, int256 price);
    event LockRound(uint256 indexed epoch, uint256 indexed roundId, int256 price);

    event NewAdminAddress(address admin);
    event NewBufferAndIntervalSeconds(uint256 bufferSeconds, uint256 intervalSeconds);
    event NewMinBetAmount(uint256 indexed epoch, uint256 minBetAmount);
    event NewTreasuryFee(uint256 indexed epoch, uint256 treasuryFee);
    event NewOperatorAddress(address operator);
    event NewOracle(address oracle);
    event NewOracleUpdateAllowance(uint256 oracleUpdateAllowance);

    event Pause(uint256 indexed epoch);
    event RewardsCalculated(
        uint256 indexed epoch,
        uint256 rewardBaseCalAmount,
        uint256 rewardAmount,
        uint256 treasuryAmount
    );

    event StartRound(uint256 indexed epoch);
    event TokenRecovery(address indexed token, uint256 amount);
    event TreasuryClaim(uint256 amount);
    event Unpause(uint256 indexed epoch);

    modifier onlyAdmin() {
        require(msg.sender == adminAddress, "Not admin");
        _;
    }

    modifier onlyAdminOrOperator() {
        require(msg.sender == adminAddress || msg.sender == operatorAddress, "Not operator/admin");
        _;
    }

    modifier onlyOperator() {
        require(msg.sender == operatorAddress, "Not operator");
        _;
    }

    modifier notContract() {
        require(!_isContract(msg.sender), "Contract not allowed");
        require(msg.sender == tx.origin, "Proxy contract not allowed");
        _;
    }

    /**
     * @notice Constructor
     * @param _token: prediction token
     * @param _oracleAddress: oracle address
     * @param _adminAddress: admin address
     * @param _operatorAddress: operator address
     * @param _intervalSeconds: number of time within an interval
     * @param _bufferSeconds: buffer of time for resolution of price
     * @param _minBetAmount: minimum bet amounts (in wei)
     * @param _oracleUpdateAllowance: oracle update allowance
     * @param _treasuryFee: treasury fee (1000 = 10%)
     */
    constructor(
        IERC20 _token,
        address _oracleAddress,
        address _adminAddress,
        address _operatorAddress,
        uint256 _intervalSeconds,
        uint256 _bufferSeconds,
        uint256 _minBetAmount,
        uint256 _oracleUpdateAllowance,
        uint256 _treasuryFee
    ) {
        require(_treasuryFee <= MAX_TREASURY_FEE, "Treasury fee too high");

        token = _token;
        oracle = AggregatorV3Interface(_oracleAddress);
        adminAddress = _adminAddress;
        operatorAddress = _operatorAddress;
        intervalSeconds = _intervalSeconds;
        bufferSeconds = _bufferSeconds;
        minBetAmount = _minBetAmount;
        oracleUpdateAllowance = _oracleUpdateAllowance;
        treasuryFee = _treasuryFee;
    }

    /**
     * @notice Bet bear position
     * @param epoch: epoch
     */
    function betBear(uint256 epoch, uint256 _amount) external whenNotPaused nonReentrant notContract {
        require(epoch == currentEpoch, "Bet is too early/late");
        require(_bettable(epoch), "Round not bettable");
        require(_amount >= minBetAmount, "Bet amount must be greater than minBetAmount");
        require(ledger[epoch][msg.sender].amount == 0, "Can only bet once per round");

        token.safeTransferFrom(msg.sender, address(this), _amount);
        // Update round data
        uint256 amount = _amount;
        Round storage round = rounds[epoch];
        round.totalAmount = round.totalAmount + amount;
        round.bearAmount = round.bearAmount + amount;

        // Update user data
        BetInfo storage betInfo = ledger[epoch][msg.sender];
        betInfo.position = Position.Bear;
        betInfo.amount = amount;
        userRounds[msg.sender].push(epoch);

        emit BetBear(msg.sender, epoch, amount);
    }

    /**
     * @notice Bet bull position
     * @param epoch: epoch
     */
    function betBull(uint256 epoch, uint256 _amount) external whenNotPaused nonReentrant notContract {
        require(epoch == currentEpoch, "Bet is too early/late");
        require(_bettable(epoch), "Round not bettable");
        require(_amount >= minBetAmount, "Bet amount must be greater than minBetAmount");
        require(ledger[epoch][msg.sender].amount == 0, "Can only bet once per round");

        token.safeTransferFrom(msg.sender, address(this), _amount);
        // Update round data
        uint256 amount = _amount;
        Round storage round = rounds[epoch];
        round.totalAmount = round.totalAmount + amount;
        round.bullAmount = round.bullAmount + amount;

        // Update user data
        BetInfo storage betInfo = ledger[epoch][msg.sender];
        betInfo.position = Position.Bull;
        betInfo.amount = amount;
        userRounds[msg.sender].push(epoch);

        emit BetBull(msg.sender, epoch, amount);
    }

    /**
     * @notice Claim reward for an array of epochs
     * @param epochs: array of epochs
     */
    function claim(uint256[] calldata epochs) external nonReentrant notContract {
        uint256 reward; // Initializes reward

        for (uint256 i = 0; i < epochs.length; i++) {
            require(rounds[epochs[i]].startTimestamp != 0, "Round has not started");
            require(block.timestamp > rounds[epochs[i]].closeTimestamp, "Round has not ended");

            uint256 addedReward = 0;

            // Round valid, claim rewards
            if (rounds[epochs[i]].oracleCalled) {
                require(claimable(epochs[i], msg.sender), "Not eligible for claim");
                Round memory round = rounds[epochs[i]];
                addedReward = (ledger[epochs[i]][msg.sender].amount * round.rewardAmount) / round.rewardBaseCalAmount;
            }
            // Round invalid, refund bet amount
            else {
                require(refundable(epochs[i], msg.sender), "Not eligible for refund");
                addedReward = ledger[epochs[i]][msg.sender].amount;
            }

            ledger[epochs[i]][msg.sender].claimed = true;
            reward += addedReward;

            emit Claim(msg.sender, epochs[i], addedReward);
        }

        if (reward > 0) {
            token.safeTransfer(msg.sender, reward);
        }
    }

    /**
     * @notice Start the next round n, lock price for round n-1, end round n-2
     * @dev Callable by operator
     */
    function executeRound() external whenNotPaused onlyOperator {
        require(
            genesisStartOnce && genesisLockOnce,
            "Can only run after genesisStartRound and genesisLockRound is triggered"
        );

        (uint80 currentRoundId, int256 currentPrice) = _getPriceFromOracle();

        oracleLatestRoundId = uint256(currentRoundId);

        // CurrentEpoch refers to previous round (n-1)
        _safeLockRound(currentEpoch, currentRoundId, currentPrice);
        _safeEndRound(currentEpoch - 1, currentRoundId, currentPrice);
        _calculateRewards(currentEpoch - 1);

        // Increment currentEpoch to current round (n)
        currentEpoch = currentEpoch + 1;
        _safeStartRound(currentEpoch);
    }

    /**
     * @notice Lock genesis round
     * @dev Callable by operator
     */
    function genesisLockRound() external whenNotPaused onlyOperator {
        require(genesisStartOnce, "Can only run after genesisStartRound is triggered");
        require(!genesisLockOnce, "Can only run genesisLockRound once");

        (uint80 currentRoundId, int256 currentPrice) = _getPriceFromOracle();

        oracleLatestRoundId = uint256(currentRoundId);

        _safeLockRound(currentEpoch, currentRoundId, currentPrice);

        currentEpoch = currentEpoch + 1;
        _startRound(currentEpoch);
        genesisLockOnce = true;
    }

    /**
     * @notice Start genesis round
     * @dev Callable by admin or operator
     */
    function genesisStartRound() external whenNotPaused onlyOperator {
        require(!genesisStartOnce, "Can only run genesisStartRound once");

        currentEpoch = currentEpoch + 1;
        _startRound(currentEpoch);
        genesisStartOnce = true;
    }

    /**
     * @notice called by the admin to pause, triggers stopped state
     * @dev Callable by admin or operator
     */
    function pause() external whenNotPaused onlyAdminOrOperator {
        _pause();

        emit Pause(currentEpoch);
    }

    /**
     * @notice Claim all rewards in treasury
     * @dev Callable by admin
     */
    function claimTreasury() external nonReentrant onlyAdmin {
        uint256 currentTreasuryAmount = treasuryAmount;
        treasuryAmount = 0;
        token.safeTransfer(adminAddress, currentTreasuryAmount);
        emit TreasuryClaim(currentTreasuryAmount);
    }

    /**
     * @notice called by the admin to unpause, returns to normal state
     * Reset genesis state. Once paused, the rounds would need to be kickstarted by genesis
     * @dev Callable by admin or operator
     */
    function unpause() external whenPaused onlyAdminOrOperator {
        genesisStartOnce = false;
        genesisLockOnce = false;
        _unpause();

        emit Unpause(currentEpoch);
    }

    /**
     * @notice Set buffer and interval (in seconds)
     * @dev Callable by admin
     */
    function setBufferAndIntervalSeconds(uint256 _bufferSeconds, uint256 _intervalSeconds)
        external
        whenPaused
        onlyAdmin
    {
        require(_bufferSeconds < _intervalSeconds, "bufferSeconds must be inferior to intervalSeconds");
        bufferSeconds = _bufferSeconds;
        intervalSeconds = _intervalSeconds;

        emit NewBufferAndIntervalSeconds(_bufferSeconds, _intervalSeconds);
    }

    /**
     * @notice Set minBetAmount
     * @dev Callable by admin
     */
    function setMinBetAmount(uint256 _minBetAmount) external whenPaused onlyAdmin {
        require(_minBetAmount != 0, "Must be superior to 0");
        minBetAmount = _minBetAmount;

        emit NewMinBetAmount(currentEpoch, minBetAmount);
    }

    /**
     * @notice Set operator address
     * @dev Callable by admin
     */
    function setOperator(address _operatorAddress) external onlyAdmin {
        require(_operatorAddress != address(0), "Cannot be zero address");
        operatorAddress = _operatorAddress;

        emit NewOperatorAddress(_operatorAddress);
    }

    /**
     * @notice Set Oracle address
     * @dev Callable by admin
     */
    function setOracle(address _oracle) external whenPaused onlyAdmin {
        require(_oracle != address(0), "Cannot be zero address");
        oracleLatestRoundId = 0;
        oracle = AggregatorV3Interface(_oracle);

        // Dummy check to make sure the interface implements this function properly
        oracle.latestRoundData();

        emit NewOracle(_oracle);
    }

    /**
     * @notice Set oracle update allowance
     * @dev Callable by admin
     */
    function setOracleUpdateAllowance(uint256 _oracleUpdateAllowance) external whenPaused onlyAdmin {
        oracleUpdateAllowance = _oracleUpdateAllowance;

        emit NewOracleUpdateAllowance(_oracleUpdateAllowance);
    }

    /**
     * @notice Set treasury fee
     * @dev Callable by admin
     */
    function setTreasuryFee(uint256 _treasuryFee) external whenPaused onlyAdmin {
        require(_treasuryFee <= MAX_TREASURY_FEE, "Treasury fee too high");
        treasuryFee = _treasuryFee;

        emit NewTreasuryFee(currentEpoch, treasuryFee);
    }

    /**
     * @notice It allows the owner to recover tokens sent to the contract by mistake
     * @param _token: token address
     * @param _amount: token amount
     * @dev Callable by owner
     */
    function recoverToken(address _token, uint256 _amount) external onlyOwner {
        require(_token != address(token), "Cannot be prediction token address");
        IERC20(_token).safeTransfer(address(msg.sender), _amount);

        emit TokenRecovery(_token, _amount);
    }

    /**
     * @notice Set admin address
     * @dev Callable by owner
     */
    function setAdmin(address _adminAddress) external onlyOwner {
        require(_adminAddress != address(0), "Cannot be zero address");
        adminAddress = _adminAddress;

        emit NewAdminAddress(_adminAddress);
    }

    /**
     * @notice Returns round epochs and bet information for a user that has participated
     * @param user: user address
     * @param cursor: cursor
     * @param size: size
     */
    function getUserRounds(
        address user,
        uint256 cursor,
        uint256 size
    )
        external
        view
        returns (
            uint256[] memory,
            BetInfo[] memory,
            uint256
        )
    {
        uint256 length = size;

        if (length > userRounds[user].length - cursor) {
            length = userRounds[user].length - cursor;
        }

        uint256[] memory values = new uint256[](length);
        BetInfo[] memory betInfo = new BetInfo[](length);

        for (uint256 i = 0; i < length; i++) {
            values[i] = userRounds[user][cursor + i];
            betInfo[i] = ledger[values[i]][user];
        }

        return (values, betInfo, cursor + length);
    }

    /**
     * @notice Returns round epochs length
     * @param user: user address
     */
    function getUserRoundsLength(address user) external view returns (uint256) {
        return userRounds[user].length;
    }

    /**
     * @notice Get the claimable stats of specific epoch and user account
     * @param epoch: epoch
     * @param user: user address
     */
    function claimable(uint256 epoch, address user) public view returns (bool) {
        BetInfo memory betInfo = ledger[epoch][user];
        Round memory round = rounds[epoch];
        if (round.lockPrice == round.closePrice) {
            return false;
        }
        return
            round.oracleCalled &&
            betInfo.amount != 0 &&
            !betInfo.claimed &&
            ((round.closePrice > round.lockPrice && betInfo.position == Position.Bull) ||
                (round.closePrice < round.lockPrice && betInfo.position == Position.Bear));
    }

    /**
     * @notice Get the refundable stats of specific epoch and user account
     * @param epoch: epoch
     * @param user: user address
     */
    function refundable(uint256 epoch, address user) public view returns (bool) {
        BetInfo memory betInfo = ledger[epoch][user];
        Round memory round = rounds[epoch];
        return
            !round.oracleCalled &&
            !betInfo.claimed &&
            block.timestamp > round.closeTimestamp + bufferSeconds &&
            betInfo.amount != 0;
    }

    /**
     * @notice Calculate rewards for round
     * @param epoch: epoch
     */
    function _calculateRewards(uint256 epoch) internal {
        require(rounds[epoch].rewardBaseCalAmount == 0 && rounds[epoch].rewardAmount == 0, "Rewards calculated");
        Round storage round = rounds[epoch];
        uint256 rewardBaseCalAmount;
        uint256 treasuryAmt;
        uint256 rewardAmount;

        // Bull wins
        if (round.closePrice > round.lockPrice) {
            rewardBaseCalAmount = round.bullAmount;
            treasuryAmt = (round.totalAmount * treasuryFee) / 10000;
            rewardAmount = round.totalAmount - treasuryAmt;
        }
        // Bear wins
        else if (round.closePrice < round.lockPrice) {
            rewardBaseCalAmount = round.bearAmount;
            treasuryAmt = (round.totalAmount * treasuryFee) / 10000;
            rewardAmount = round.totalAmount - treasuryAmt;
        }
        // House wins
        else {
            rewardBaseCalAmount = 0;
            rewardAmount = 0;
            treasuryAmt = round.totalAmount;
        }
        round.rewardBaseCalAmount = rewardBaseCalAmount;
        round.rewardAmount = rewardAmount;

        // Add to treasury
        treasuryAmount += treasuryAmt;

        emit RewardsCalculated(epoch, rewardBaseCalAmount, rewardAmount, treasuryAmt);
    }

    /**
     * @notice End round
     * @param epoch: epoch
     * @param roundId: roundId
     * @param price: price of the round
     */
    function _safeEndRound(
        uint256 epoch,
        uint256 roundId,
        int256 price
    ) internal {
        require(rounds[epoch].lockTimestamp != 0, "Can only end round after round has locked");
        require(block.timestamp >= rounds[epoch].closeTimestamp, "Can only end round after closeTimestamp");
        require(
            block.timestamp <= rounds[epoch].closeTimestamp + bufferSeconds,
            "Can only end round within bufferSeconds"
        );
        Round storage round = rounds[epoch];
        round.closePrice = price;
        round.closeOracleId = roundId;
        round.oracleCalled = true;

        emit EndRound(epoch, roundId, round.closePrice);
    }

    /**
     * @notice Lock round
     * @param epoch: epoch
     * @param roundId: roundId
     * @param price: price of the round
     */
    function _safeLockRound(
        uint256 epoch,
        uint256 roundId,
        int256 price
    ) internal {
        require(rounds[epoch].startTimestamp != 0, "Can only lock round after round has started");
        require(block.timestamp >= rounds[epoch].lockTimestamp, "Can only lock round after lockTimestamp");
        require(
            block.timestamp <= rounds[epoch].lockTimestamp + bufferSeconds,
            "Can only lock round within bufferSeconds"
        );
        Round storage round = rounds[epoch];
        round.closeTimestamp = block.timestamp + intervalSeconds;
        round.lockPrice = price;
        round.lockOracleId = roundId;

        emit LockRound(epoch, roundId, round.lockPrice);
    }

    /**
     * @notice Start round
     * Previous round n-2 must end
     * @param epoch: epoch
     */
    function _safeStartRound(uint256 epoch) internal {
        require(genesisStartOnce, "Can only run after genesisStartRound is triggered");
        require(rounds[epoch - 2].closeTimestamp != 0, "Can only start round after round n-2 has ended");
        require(
            block.timestamp >= rounds[epoch - 2].closeTimestamp,
            "Can only start new round after round n-2 closeTimestamp"
        );
        _startRound(epoch);
    }

    /**
     * @notice Start round
     * Previous round n-2 must end
     * @param epoch: epoch
     */
    function _startRound(uint256 epoch) internal {
        Round storage round = rounds[epoch];
        round.startTimestamp = block.timestamp;
        round.lockTimestamp = block.timestamp + intervalSeconds;
        round.closeTimestamp = block.timestamp + (2 * intervalSeconds);
        round.epoch = epoch;
        round.totalAmount = 0;

        emit StartRound(epoch);
    }

    /**
     * @notice Determine if a round is valid for receiving bets
     * Round must have started and locked
     * Current timestamp must be within startTimestamp and closeTimestamp
     */
    function _bettable(uint256 epoch) internal view returns (bool) {
        return
            rounds[epoch].startTimestamp != 0 &&
            rounds[epoch].lockTimestamp != 0 &&
            block.timestamp > rounds[epoch].startTimestamp &&
            block.timestamp < rounds[epoch].lockTimestamp;
    }

    /**
     * @notice Get latest recorded price from oracle
     * If it falls below allowed buffer or has not updated, it would be invalid.
     */
    function _getPriceFromOracle() internal view returns (uint80, int256) {
        uint256 leastAllowedTimestamp = block.timestamp + oracleUpdateAllowance;
        (uint80 roundId, int256 price, , uint256 timestamp, ) = oracle.latestRoundData();
        require(timestamp <= leastAllowedTimestamp, "Oracle update exceeded max timestamp allowance");
        require(
            uint256(roundId) > oracleLatestRoundId,
            "Oracle update roundId must be larger than oracleLatestRoundId"
        );
        return (roundId, price);
    }

    /**
     * @notice Returns true if `account` is a contract.
     * @param account: account address
     */
    function _isContract(address account) internal view returns (bool) {
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
}