// File: solidity/contracts/token/SPLToken.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.19;

import {SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {ERC20Capped, ERC20, IERC20} from '@openzeppelin/contracts/token/ERC20/extensions/ERC20Capped.sol';
import {Ownable} from '@openzeppelin/contracts/access/Ownable.sol';
import {Pausable} from '@openzeppelin/contracts/security/Pausable.sol';
import {AggregatorV3Interface} from '../../interfaces/IAggregatorV3Interface.sol';
import {ISPLToken} from '../../interfaces/ISPLToken.sol';

/**
 * @title SPL token for launch
 * @author Splendor Network
 * @notice This contract has a system to collaterized the price
 * to wBTC taking info from Chainlink Price Feeds
 * @notice Check the prices in chainlink with  capacity to remove it
 */

contract SPLToken is ERC20Capped, Ownable, ISPLToken, Pausable {
  using SafeERC20 for IERC20;

  AggregatorV3Interface internal priceFeedWBTC;
  AggregatorV3Interface internal priceFeedCGLD;

  address public WBTC;
  address public CGLD;
  /*/////////////////////////////////
                    ERRORS           
  /////////////////////////////////*/

  error SplendorToken__NotEnoughBalance();
  error SplendorToken__FunctionPaused();

  constructor(
    address _WBTC,
    address _CGLD,
    address _priceFeedWBTC,
    address _priceFeedCGLD
  ) ERC20('SPL', 'Splendor') ERC20Capped(187_500e18) {
    WBTC = _WBTC;
    CGLD = _CGLD;
    priceFeedWBTC = AggregatorV3Interface(_priceFeedWBTC);
    priceFeedCGLD = AggregatorV3Interface(_priceFeedCGLD);
  }

  /**
   * @dev Function to buy SPL
   * @param _amount amount of SPL that the user wants buy
   * @notice We need to have Request Approve from Dapp by The User
   * @return true
   */
  function buySplendorWithWBTC(uint256 _amount) external returns (bool) {
    if (getWBTCUserBalance(_msgSender()) < _amount) {
      revert SplendorToken__NotEnoughBalance();
    }
    IERC20(WBTC).safeTransferFrom(_msgSender(), owner(), _amount);
    _mint(_msgSender(), _amount);
    emit TokenBoughtWithWBTC(_msgSender(), _amount);
    return true;
  }

  /**
   * @dev Function to buy SPL token with CGLD token
   * @param _amount spl with CGLD
   * @return true
   */
  function buySplendorWithCGLD(uint256 _amount) external returns (bool) {
    if (getCGLDUserBalance(_msgSender()) < calculatePrice(_amount)) {
      revert SplendorToken__NotEnoughBalance();
    }
    if (paused()) {
      revert SplendorToken__FunctionPaused();
    }
    IERC20(CGLD).safeTransferFrom(_msgSender(), owner(), calculatePrice(_amount));
    _mint(_msgSender(), _amount);
    emit TokenBoughtWithCGLD(_msgSender(), _amount, calculatePrice(_amount));
    return true;
  }

  /**
   * @return price calculated in CGLD of SPL cost
   * @notice Is a formula:
   * priceOfSPLInUSD(_amount) / priceOfCGLDInIUSD(1)
   */
  function calculatePrice(uint256 _amount) public view returns (uint256) {
    uint256 price = getPriceOfSPLInUSD(_amount) / getPriceOfCGLDInUSD(1);
    return price;
  }

  /*///////////////////////////////////////////////////////////////
                       ADMIN FUNCTIONS
  //////////////////////////////////////////////////////////////*/

  /**
   * @notice Function to pause some functions
   */
  function pause() external onlyOwner {
    _pause();
  }

  /*///////////////////////////////////////////////////////////////
                       CHAINLINK FUNCTIONS
  //////////////////////////////////////////////////////////////*/

  /**
   * @return price of WBTC in USD obtained from chainlink price feed
   */
  function getLatestWBTCInUSDPrice() public view returns (int256) {
    (, int256 price,,,) = priceFeedWBTC.latestRoundData();
    return price;
  }

  /**
   * @return price of CGLD in USD obtained from chainlink price feed
   */
  function getLatestCGLDInUSDPrice() public view returns (int256) {
    (, int256 price,,,) = priceFeedCGLD.latestRoundData();
    return price;
  }

  /**
   * @return price of SPL in USD
   */
  function getPriceOfSPLInUSD(uint256 _amount) public view returns (uint256) {
    uint256 price = uint256(getLatestWBTCInUSDPrice() * 10 ** 10);
    uint256 __price = price * _amount;
    return __price;
  }

  /**
   * @return price of SPL in USD
   */
  function getPriceOfCGLDInUSD(uint256 _amount) public view returns (uint256) {
    uint256 price = uint256(getLatestCGLDInUSDPrice() * 10 ** 10);
    uint256 __price = price * _amount;
    return __price;
  }

  /*///////////////////////////////////////////////////////////////
                        GETTER FUNCTIONS
  //////////////////////////////////////////////////////////////*/

  /**
   * @return balance of WBTC of _msgSender()
   */
  function getWBTCUserBalance(address _user) internal view returns (uint256) {
    return IERC20(WBTC).balanceOf(_user);
  }

  /**
   * @return balance of CGLD of _msgSender()
   */
  function getCGLDUserBalance(address _user) internal view returns (uint256) {
    return IERC20(CGLD).balanceOf(_user);
  }
}

// File: lib/openzeppelin-contracts/contracts/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import '../IERC20.sol';
import '../extensions/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;

  /**
   * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
   * non-reverting calls are assumed to be successful.
   */
  function safeTransfer(IERC20 token, address to, uint256 value) internal {
    _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
  }

  /**
   * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
   * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
   */
  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));
  }

  /**
   * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
   * non-reverting calls are assumed to be successful.
   */
  function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
    uint256 oldAllowance = token.allowance(address(this), spender);
    _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance + value));
  }

  /**
   * @dev Decrease the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
   * non-reverting calls are assumed to be successful.
   */
  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');
      _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, oldAllowance - value));
    }
  }

  /**
   * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
   * non-reverting calls are assumed to be successful. Compatible with tokens that require the approval to be set to
   * 0 before setting it to a non-zero value.
   */
  function forceApprove(IERC20 token, address spender, uint256 value) internal {
    bytes memory approvalCall = abi.encodeWithSelector(token.approve.selector, spender, value);

    if (!_callOptionalReturnBool(token, approvalCall)) {
      _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, 0));
      _callOptionalReturn(token, approvalCall);
    }
  }

  /**
   * @dev Use a ERC-2612 signature to set the `owner` approval toward `spender` on `token`.
   * Revert on invalid signature.
   */
  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');
    require(returndata.length == 0 || abi.decode(returndata, (bool)), 'SafeERC20: ERC20 operation 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).
   *
   * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
   */
  function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
    // 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 cannot use {Address-functionCall} here since this should return false
    // and not revert is the subcall reverts.

    (bool success, bytes memory returndata) = address(token).call(data);
    return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && Address.isContract(address(token));
  }
}

// File: lib/openzeppelin-contracts/contracts/token/ERC20/extensions/ERC20Capped.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/ERC20Capped.sol)

pragma solidity ^0.8.0;

import '../ERC20.sol';

/**
 * @dev Extension of {ERC20} that adds a cap to the supply of tokens.
 */
abstract contract ERC20Capped is ERC20 {
  uint256 private immutable _cap;

  /**
   * @dev Sets the value of the `cap`. This value is immutable, it can only be
   * set once during construction.
   */
  constructor(uint256 cap_) {
    require(cap_ > 0, 'ERC20Capped: cap is 0');
    _cap = cap_;
  }

  /**
   * @dev Returns the cap on the token's total supply.
   */
  function cap() public view virtual returns (uint256) {
    return _cap;
  }

  /**
   * @dev See {ERC20-_mint}.
   */
  function _mint(address account, uint256 amount) internal virtual override {
    require(ERC20.totalSupply() + amount <= cap(), 'ERC20Capped: cap exceeded');
    super._mint(account, amount);
  }
}

// File: lib/openzeppelin-contracts/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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. Can only be called by the current owner.
   *
   * NOTE: Renouncing ownership will leave the contract without an owner,
   * thereby disabling 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: lib/openzeppelin-contracts/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: solidity/interfaces/IAggregatorV3Interface.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

/**
 * @title Aggregator Interface
 * @author Splendor Network
 */

interface AggregatorV3Interface {
  /*///////////////////////////////////////////////////////////////
                            METHODS
  //////////////////////////////////////////////////////////////*/

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

// File: solidity/interfaces/ISPLToken.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

/**
 * @title SPL Interface
 * @author Splendor Network
 * @notice This is the interface of the token of SPL
 */
interface ISPLToken {
  /*///////////////////////////////////////////////////////////////
                            EVENTS
  //////////////////////////////////////////////////////////////*/

  /// @dev Emitted when the user bougth Tokens
  event TokenBoughtWithWBTC(address buyer, uint256 amount);

  /// @dev Emitted when the user bougth Tokens
  event TokenBoughtWithCGLD(address buyer, uint256 amount, uint256 price);
}

// File: lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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: lib/openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Permit.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/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: lib/openzeppelin-contracts/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (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
   *
   * Furthermore, `isContract` will also return true if the target contract within
   * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
   * which only has an effect at the end of a transaction.
   * ====
   *
   * [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://consensys.net/diligence/blog/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/v0.8.0/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: lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import './IERC20.sol';
import './extensions/IERC20Metadata.sol';
import '../../utils/Context.sol';

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
  mapping(address => uint256) private _balances;

  mapping(address => mapping(address => uint256)) private _allowances;

  uint256 private _totalSupply;

  string private _name;
  string private _symbol;

  /**
   * @dev Sets the values for {name} and {symbol}.
   *
   * All two of these values are immutable: they can only be set once during
   * construction.
   */
  constructor(string memory name_, string memory symbol_) {
    _name = name_;
    _symbol = symbol_;
  }

  /**
   * @dev Returns the name of the token.
   */
  function name() public view virtual override returns (string memory) {
    return _name;
  }

  /**
   * @dev Returns the symbol of the token, usually a shorter version of the
   * name.
   */
  function symbol() public view virtual override returns (string memory) {
    return _symbol;
  }

  /**
   * @dev Returns the number of decimals used to get its user representation.
   * For example, if `decimals` equals `2`, a balance of `505` tokens should
   * be displayed to a user as `5.05` (`505 / 10 ** 2`).
   *
   * Tokens usually opt for a value of 18, imitating the relationship between
   * Ether and Wei. This is the default value returned by this function, unless
   * it's overridden.
   *
   * NOTE: This information is only used for _display_ purposes: it in
   * no way affects any of the arithmetic of the contract, including
   * {IERC20-balanceOf} and {IERC20-transfer}.
   */
  function decimals() public view virtual override returns (uint8) {
    return 18;
  }

  /**
   * @dev See {IERC20-totalSupply}.
   */
  function totalSupply() public view virtual override returns (uint256) {
    return _totalSupply;
  }

  /**
   * @dev See {IERC20-balanceOf}.
   */
  function balanceOf(address account) public view virtual override returns (uint256) {
    return _balances[account];
  }

  /**
   * @dev See {IERC20-transfer}.
   *
   * Requirements:
   *
   * - `to` cannot be the zero address.
   * - the caller must have a balance of at least `amount`.
   */
  function transfer(address to, uint256 amount) public virtual override returns (bool) {
    address owner = _msgSender();
    _transfer(owner, to, amount);
    return true;
  }

  /**
   * @dev See {IERC20-allowance}.
   */
  function allowance(address owner, address spender) public view virtual override returns (uint256) {
    return _allowances[owner][spender];
  }

  /**
   * @dev See {IERC20-approve}.
   *
   * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
   * `transferFrom`. This is semantically equivalent to an infinite approval.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function approve(address spender, uint256 amount) public virtual override returns (bool) {
    address owner = _msgSender();
    _approve(owner, spender, amount);
    return true;
  }

  /**
   * @dev See {IERC20-transferFrom}.
   *
   * Emits an {Approval} event indicating the updated allowance. This is not
   * required by the EIP. See the note at the beginning of {ERC20}.
   *
   * NOTE: Does not update the allowance if the current allowance
   * is the maximum `uint256`.
   *
   * Requirements:
   *
   * - `from` and `to` cannot be the zero address.
   * - `from` must have a balance of at least `amount`.
   * - the caller must have allowance for ``from``'s tokens of at least
   * `amount`.
   */
  function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
    address spender = _msgSender();
    _spendAllowance(from, spender, amount);
    _transfer(from, to, amount);
    return true;
  }

  /**
   * @dev Atomically increases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
    address owner = _msgSender();
    _approve(owner, spender, allowance(owner, spender) + addedValue);
    return true;
  }

  /**
   * @dev Atomically decreases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to {approve} that can be used as a mitigation for
   * problems described in {IERC20-approve}.
   *
   * Emits an {Approval} event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   * - `spender` must have allowance for the caller of at least
   * `subtractedValue`.
   */
  function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
    address owner = _msgSender();
    uint256 currentAllowance = allowance(owner, spender);
    require(currentAllowance >= subtractedValue, 'ERC20: decreased allowance below zero');
    unchecked {
      _approve(owner, spender, currentAllowance - subtractedValue);
    }

    return true;
  }

  /**
   * @dev Moves `amount` of tokens from `from` to `to`.
   *
   * This internal function is equivalent to {transfer}, and can be used to
   * e.g. implement automatic token fees, slashing mechanisms, etc.
   *
   * Emits a {Transfer} event.
   *
   * Requirements:
   *
   * - `from` cannot be the zero address.
   * - `to` cannot be the zero address.
   * - `from` must have a balance of at least `amount`.
   */
  function _transfer(address from, address to, uint256 amount) internal virtual {
    require(from != address(0), 'ERC20: transfer from the zero address');
    require(to != address(0), 'ERC20: transfer to the zero address');

    _beforeTokenTransfer(from, to, amount);

    uint256 fromBalance = _balances[from];
    require(fromBalance >= amount, 'ERC20: transfer amount exceeds balance');
    unchecked {
      _balances[from] = fromBalance - amount;
      // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
      // decrementing then incrementing.
      _balances[to] += amount;
    }

    emit Transfer(from, to, amount);

    _afterTokenTransfer(from, to, amount);
  }

  /**
   * @dev Creates `amount` tokens and assigns them to `account`, increasing
   * the total supply.
   *
   * Emits a {Transfer} event with `from` set to the zero address.
   *
   * Requirements:
   *
   * - `account` cannot be the zero address.
   */
  function _mint(address account, uint256 amount) internal virtual {
    require(account != address(0), 'ERC20: mint to the zero address');

    _beforeTokenTransfer(address(0), account, amount);

    _totalSupply += amount;
    unchecked {
      // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
      _balances[account] += amount;
    }
    emit Transfer(address(0), account, amount);

    _afterTokenTransfer(address(0), account, amount);
  }

  /**
   * @dev Destroys `amount` tokens from `account`, reducing the
   * total supply.
   *
   * Emits a {Transfer} event with `to` set to the zero address.
   *
   * Requirements:
   *
   * - `account` cannot be the zero address.
   * - `account` must have at least `amount` tokens.
   */
  function _burn(address account, uint256 amount) internal virtual {
    require(account != address(0), 'ERC20: burn from the zero address');

    _beforeTokenTransfer(account, address(0), amount);

    uint256 accountBalance = _balances[account];
    require(accountBalance >= amount, 'ERC20: burn amount exceeds balance');
    unchecked {
      _balances[account] = accountBalance - amount;
      // Overflow not possible: amount <= accountBalance <= totalSupply.
      _totalSupply -= amount;
    }

    emit Transfer(account, address(0), amount);

    _afterTokenTransfer(account, address(0), amount);
  }

  /**
   * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
   *
   * This internal function is equivalent to `approve`, and can be used to
   * e.g. set automatic allowances for certain subsystems, etc.
   *
   * Emits an {Approval} event.
   *
   * Requirements:
   *
   * - `owner` cannot be the zero address.
   * - `spender` cannot be the zero address.
   */
  function _approve(address owner, address spender, uint256 amount) internal virtual {
    require(owner != address(0), 'ERC20: approve from the zero address');
    require(spender != address(0), 'ERC20: approve to the zero address');

    _allowances[owner][spender] = amount;
    emit Approval(owner, spender, amount);
  }

  /**
   * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
   *
   * Does not update the allowance amount in case of infinite allowance.
   * Revert if not enough allowance is available.
   *
   * Might emit an {Approval} event.
   */
  function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
    uint256 currentAllowance = allowance(owner, spender);
    if (currentAllowance != type(uint256).max) {
      require(currentAllowance >= amount, 'ERC20: insufficient allowance');
      unchecked {
        _approve(owner, spender, currentAllowance - amount);
      }
    }
  }

  /**
   * @dev Hook that is called before any transfer of tokens. This includes
   * minting and burning.
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
   * will be transferred to `to`.
   * - when `from` is zero, `amount` tokens will be minted for `to`.
   * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
   * - `from` and `to` are never both zero.
   *
   * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
   */
  function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

  /**
   * @dev Hook that is called after any transfer of tokens. This includes
   * minting and burning.
   *
   * Calling conditions:
   *
   * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
   * has been transferred to `to`.
   * - when `from` is zero, `amount` tokens have been minted for `to`.
   * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
   * - `from` and `to` are never both zero.
   *
   * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
   */
  function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

// File: lib/openzeppelin-contracts/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: lib/openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import '../IERC20.sol';

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
  /**
   * @dev Returns the name of the token.
   */
  function name() external view returns (string memory);

  /**
   * @dev Returns the symbol of the token.
   */
  function symbol() external view returns (string memory);

  /**
   * @dev Returns the decimals places of the token.
   */
  function decimals() external view returns (uint8);
}