// SPDX-License-Identifier: MIT

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) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

import "@openzeppelin/contracts/access/Ownable.sol";

import "./IERC20WithPermit.sol";
import "./IReceiveApproval.sol";

/// @title  ERC20WithPermit
/// @notice Burnable ERC20 token with EIP2612 permit functionality. User can
///         authorize a transfer of their token with a signature conforming
///         EIP712 standard instead of an on-chain transaction from their
///         address. Anyone can submit this signature on the user's behalf by
///         calling the permit function, as specified in EIP2612 standard,
///         paying gas fees, and possibly performing other actions in the same
///         transaction.
contract ERC20WithPermit is IERC20WithPermit, Ownable {
    /// @notice The amount of tokens owned by the given account.
    mapping(address => uint256) public override balanceOf;

    /// @notice The remaining number of tokens that spender will be
    ///         allowed to spend on behalf of owner through `transferFrom` and
    ///         `burnFrom`. This is zero by default.
    mapping(address => mapping(address => uint256)) public override allowance;

    /// @notice Returns the current nonce for EIP2612 permission for the
    ///         provided token owner for a replay protection. Used to construct
    ///         EIP2612 signature provided to `permit` function.
    mapping(address => uint256) public override nonces;

    uint256 public immutable cachedChainId;
    bytes32 public immutable cachedDomainSeparator;

    /// @notice Returns EIP2612 Permit message hash. Used to construct EIP2612
    ///         signature provided to `permit` function.
    bytes32 public constant override PERMIT_TYPEHASH =
        keccak256(
            "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
        );

    /// @notice The amount of tokens in existence.
    uint256 public override totalSupply;

    /// @notice The name of the token.
    string public override name;

    /// @notice The symbol of the token.
    string public override symbol;

    /// @notice The decimals places of the token.
    uint8 public constant override decimals = 18;

    constructor(string memory _name, string memory _symbol) {
        name = _name;
        symbol = _symbol;

        cachedChainId = block.chainid;
        cachedDomainSeparator = buildDomainSeparator();
    }

    /// @notice Moves `amount` tokens from the caller's account to `recipient`.
    /// @return True if the operation succeeded, reverts otherwise.
    /// @dev Requirements:
    ///       - `recipient` cannot be the zero address,
    ///       - the caller must have a balance of at least `amount`.
    function transfer(address recipient, uint256 amount)
        external
        override
        returns (bool)
    {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    /// @notice Moves `amount` tokens from `sender` to `recipient` using the
    ///         allowance mechanism. `amount` is then deducted from the caller's
    ///         allowance unless the allowance was made for `type(uint256).max`.
    /// @return True if the operation succeeded, reverts otherwise.
    /// @dev Requirements:
    ///      - `sender` and `recipient` cannot be the zero address,
    ///      - `sender` must have a balance of at least `amount`,
    ///      - the caller must have allowance for `sender`'s tokens of at least
    ///        `amount`.
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external override returns (bool) {
        uint256 currentAllowance = allowance[sender][msg.sender];
        if (currentAllowance != type(uint256).max) {
            require(
                currentAllowance >= amount,
                "Transfer amount exceeds allowance"
            );
            _approve(sender, msg.sender, currentAllowance - amount);
        }
        _transfer(sender, recipient, amount);
        return true;
    }

    /// @notice EIP2612 approval made with secp256k1 signature.
    ///         Users can authorize a transfer of their tokens with a signature
    ///         conforming EIP712 standard, rather than an on-chain transaction
    ///         from their address. Anyone can submit this signature on the
    ///         user's behalf by calling the permit function, paying gas fees,
    ///         and possibly performing other actions in the same transaction.
    /// @dev    The deadline argument can be set to `type(uint256).max to create
    ///         permits that effectively never expire.  If the `amount` is set
    ///         to `type(uint256).max` then `transferFrom` and `burnFrom` will
    ///         not reduce an allowance.
    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external override {
        /* solhint-disable-next-line not-rely-on-time */
        require(deadline >= block.timestamp, "Permission expired");

        // Validate `s` and `v` values for a malleability concern described in EIP2.
        // Only signatures with `s` value in the lower half of the secp256k1
        // curve's order and `v` value of 27 or 28 are considered valid.
        require(
            uint256(s) <=
                0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0,
            "Invalid signature 's' value"
        );
        require(v == 27 || v == 28, "Invalid signature 'v' value");

        bytes32 digest = keccak256(
            abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR(),
                keccak256(
                    abi.encode(
                        PERMIT_TYPEHASH,
                        owner,
                        spender,
                        amount,
                        nonces[owner]++,
                        deadline
                    )
                )
            )
        );
        address recoveredAddress = ecrecover(digest, v, r, s);
        require(
            recoveredAddress != address(0) && recoveredAddress == owner,
            "Invalid signature"
        );
        _approve(owner, spender, amount);
    }

    /// @notice Creates `amount` tokens and assigns them to `account`,
    ///         increasing the total supply.
    /// @dev Requirements:
    ///      - `recipient` cannot be the zero address.
    function mint(address recipient, uint256 amount) external onlyOwner {
        require(recipient != address(0), "Mint to the zero address");

        beforeTokenTransfer(address(0), recipient, amount);

        totalSupply += amount;
        balanceOf[recipient] += amount;
        emit Transfer(address(0), recipient, amount);
    }

    /// @notice Destroys `amount` tokens from the caller.
    /// @dev Requirements:
    ///       - the caller must have a balance of at least `amount`.
    function burn(uint256 amount) external override {
        _burn(msg.sender, amount);
    }

    /// @notice Destroys `amount` of tokens from `account` using the allowance
    ///         mechanism. `amount` is then deducted from the caller's allowance
    ///         unless the allowance was made for `type(uint256).max`.
    /// @dev Requirements:
    ///      - `account` must have a balance of at least `amount`,
    ///      - the caller must have allowance for `account`'s tokens of at least
    ///        `amount`.
    function burnFrom(address account, uint256 amount) external override {
        uint256 currentAllowance = allowance[account][msg.sender];
        if (currentAllowance != type(uint256).max) {
            require(
                currentAllowance >= amount,
                "Burn amount exceeds allowance"
            );
            _approve(account, msg.sender, currentAllowance - amount);
        }
        _burn(account, amount);
    }

    /// @notice Calls `receiveApproval` function on spender previously approving
    ///         the spender to withdraw from the caller multiple times, up to
    ///         the `amount` amount. If this function is called again, it
    ///         overwrites the current allowance with `amount`. Reverts if the
    ///         approval reverted or if `receiveApproval` call on the spender
    ///         reverted.
    /// @return True if both approval and `receiveApproval` calls succeeded.
    /// @dev If the `amount` is set to `type(uint256).max` then
    ///      `transferFrom` and `burnFrom` will not reduce an allowance.
    function approveAndCall(
        address spender,
        uint256 amount,
        bytes memory extraData
    ) external override returns (bool) {
        if (approve(spender, amount)) {
            IReceiveApproval(spender).receiveApproval(
                msg.sender,
                amount,
                address(this),
                extraData
            );
            return true;
        }
        return false;
    }

    /// @notice Sets `amount` as the allowance of `spender` over the caller's
    ///         tokens.
    /// @return True if the operation succeeded.
    /// @dev If the `amount` is set to `type(uint256).max` then
    ///      `transferFrom` and `burnFrom` will not reduce an allowance.
    ///      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
    function approve(address spender, uint256 amount)
        public
        override
        returns (bool)
    {
        _approve(msg.sender, spender, amount);
        return true;
    }

    /// @notice Returns hash of EIP712 Domain struct with the token name as
    ///         a signing domain and token contract as a verifying contract.
    ///         Used to construct EIP2612 signature provided to `permit`
    ///         function.
    /* solhint-disable-next-line func-name-mixedcase */
    function DOMAIN_SEPARATOR() public view override returns (bytes32) {
        // As explained in EIP-2612, if the DOMAIN_SEPARATOR contains the
        // chainId and is defined at contract deployment instead of
        // reconstructed for every signature, there is a risk of possible replay
        // attacks between chains in the event of a future chain split.
        // To address this issue, we check the cached chain ID against the
        // current one and in case they are different, we build domain separator
        // from scratch.
        if (block.chainid == cachedChainId) {
            return cachedDomainSeparator;
        } else {
            return buildDomainSeparator();
        }
    }

    /// @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 to 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.
    // slither-disable-next-line dead-code
    function beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _burn(address account, uint256 amount) internal {
        uint256 currentBalance = balanceOf[account];
        require(currentBalance >= amount, "Burn amount exceeds balance");

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

        balanceOf[account] = currentBalance - amount;
        totalSupply -= amount;
        emit Transfer(account, address(0), amount);
    }

    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) private {
        require(sender != address(0), "Transfer from the zero address");
        require(recipient != address(0), "Transfer to the zero address");
        require(recipient != address(this), "Transfer to the token address");

        beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = balanceOf[sender];
        require(senderBalance >= amount, "Transfer amount exceeds balance");
        balanceOf[sender] = senderBalance - amount;
        balanceOf[recipient] += amount;
        emit Transfer(sender, recipient, amount);
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) private {
        require(owner != address(0), "Approve from the zero address");
        require(spender != address(0), "Approve to the zero address");
        allowance[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function buildDomainSeparator() private view returns (bytes32) {
        return
            keccak256(
                abi.encode(
                    keccak256(
                        "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
                    ),
                    keccak256(bytes(name)),
                    keccak256(bytes("1")),
                    block.chainid,
                    address(this)
                )
            );
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

/// @notice An interface that should be implemented by tokens supporting
///         `approveAndCall`/`receiveApproval` pattern.
interface IApproveAndCall {
    /// @notice Executes `receiveApproval` function on spender as specified in
    ///         `IReceiveApproval` interface. Approves spender to withdraw from
    ///         the caller multiple times, up to the `amount`. If this
    ///         function is called again, it overwrites the current allowance
    ///         with `amount`. Reverts if the approval reverted or if
    ///         `receiveApproval` call on the spender reverted.
    function approveAndCall(
        address spender,
        uint256 amount,
        bytes memory extraData
    ) external returns (bool);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

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

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// SPDX-License-Identifier: MIT

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);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";

import "./IApproveAndCall.sol";

/// @title  IERC20WithPermit
/// @notice Burnable ERC20 token with EIP2612 permit functionality. User can
///         authorize a transfer of their token with a signature conforming
///         EIP712 standard instead of an on-chain transaction from their
///         address. Anyone can submit this signature on the user's behalf by
///         calling the permit function, as specified in EIP2612 standard,
///         paying gas fees, and possibly performing other actions in the same
///         transaction.
interface IERC20WithPermit is IERC20, IERC20Metadata, IApproveAndCall {
    /// @notice EIP2612 approval made with secp256k1 signature.
    ///         Users can authorize a transfer of their tokens with a signature
    ///         conforming EIP712 standard, rather than an on-chain transaction
    ///         from their address. Anyone can submit this signature on the
    ///         user's behalf by calling the permit function, paying gas fees,
    ///         and possibly performing other actions in the same transaction.
    /// @dev    The deadline argument can be set to `type(uint256).max to create
    ///         permits that effectively never expire.
    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /// @notice Destroys `amount` tokens from the caller.
    function burn(uint256 amount) external;

    /// @notice Destroys `amount` of tokens from `account`, deducting the amount
    ///         from caller's allowance.
    function burnFrom(address account, uint256 amount) external;

    /// @notice Returns hash of EIP712 Domain struct with the token name as
    ///         a signing domain and token contract as a verifying contract.
    ///         Used to construct EIP2612 signature provided to `permit`
    ///         function.
    /* solhint-disable-next-line func-name-mixedcase */
    function DOMAIN_SEPARATOR() external view returns (bytes32);

    /// @notice Returns the current nonce for EIP2612 permission for the
    ///         provided token owner for a replay protection. Used to construct
    ///         EIP2612 signature provided to `permit` function.
    function nonces(address owner) external view returns (uint256);

    /// @notice Returns EIP2612 Permit message hash. Used to construct EIP2612
    ///         signature provided to `permit` function.
    /* solhint-disable-next-line func-name-mixedcase */
    function PERMIT_TYPEHASH() external pure returns (bytes32);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

/// @notice An interface that should be implemented by contracts supporting
///         `approveAndCall`/`receiveApproval` pattern.
interface IReceiveApproval {
    /// @notice Receives approval to spend tokens. Called as a result of
    ///         `approveAndCall` call on the token.
    function receiveApproval(
        address from,
        uint256 amount,
        address token,
        bytes calldata extraData
    ) external;
}

// SPDX-License-Identifier: MIT

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 () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// ▓▓▌ ▓▓ ▐▓▓ ▓▓▓▓▓▓▓▓▓▓▌▐▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▄
// ▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▌▐▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
//   ▓▓▓▓▓▓    ▓▓▓▓▓▓▓▀    ▐▓▓▓▓▓▓    ▐▓▓▓▓▓   ▓▓▓▓▓▓     ▓▓▓▓▓   ▐▓▓▓▓▓▌   ▐▓▓▓▓▓▓
//   ▓▓▓▓▓▓▄▄▓▓▓▓▓▓▓▀      ▐▓▓▓▓▓▓▄▄▄▄         ▓▓▓▓▓▓▄▄▄▄         ▐▓▓▓▓▓▌   ▐▓▓▓▓▓▓
//   ▓▓▓▓▓▓▓▓▓▓▓▓▓▀        ▐▓▓▓▓▓▓▓▓▓▓         ▓▓▓▓▓▓▓▓▓▓         ▐▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓
//   ▓▓▓▓▓▓▀▀▓▓▓▓▓▓▄       ▐▓▓▓▓▓▓▀▀▀▀         ▓▓▓▓▓▓▀▀▀▀         ▐▓▓▓▓▓▓▓▓▓▓▓▓▓▓▀
//   ▓▓▓▓▓▓   ▀▓▓▓▓▓▓▄     ▐▓▓▓▓▓▓     ▓▓▓▓▓   ▓▓▓▓▓▓     ▓▓▓▓▓   ▐▓▓▓▓▓▌
// ▓▓▓▓▓▓▓▓▓▓ █▓▓▓▓▓▓▓▓▓ ▐▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓  ▓▓▓▓▓▓▓▓▓▓
// ▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓ ▐▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓ ▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓▓  ▓▓▓▓▓▓▓▓▓▓
//
//                           Trust math, not hardware.

// SPDX-License-Identifier: MIT

pragma solidity 0.8.5;

import "@thesis/solidity-contracts/contracts/token/ERC20WithPermit.sol";

/// @title  UnderwriterToken
/// @notice Underwriter tokens represent an ownership share in the underlying
///         collateral of the asset-specific pool. Underwriter tokens are minted
///         when a user deposits ERC20 tokens into asset-specific pool and they
///         are burned when a user exits the position. Underwriter tokens
///         natively support meta transactions. Users can authorize a transfer
///         of their underwriter tokens with a signature conforming EIP712
///         standard instead of an on-chain transaction from their address.
///         Anyone can submit this signature on the user's behalf by calling the
///         permit function, as specified in EIP2612 standard, paying gas fees,
///         and possibly performing other actions in the same transaction.
contract UnderwriterToken is ERC20WithPermit {
    constructor(string memory _name, string memory _symbol)
        ERC20WithPermit(_name, _symbol)
    {}
}

{
  "compilationTarget": {
    "contracts/UnderwriterToken.sol": "UnderwriterToken"
  },
  "evmVersion": "berlin",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs",
    "useLiteralContent": true
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}