ethereum-standards 0.1.3

// SPDX-License-Identifier: MIT
// This interface combines methods from three OpenZeppelin contracts:
//
// IERC20.sol (base ERC-20 interface)
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol
//
// IERC20Metadata.sol (ERC-20 metadata extension)
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/extensions/IERC20Metadata.sol
//
// IERC20Permit.sol (EIP-2612 permit extension)
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/extensions/IERC20Permit.sol
//
pragma solidity ^0.8.20;

///
/// @dev Interface combining the ERC-20 standard, its metadata extension, and EIP-2612 permit.
/// Note: Due to ABI generation constraints, all interfaces are merged into a single contract.
///
interface IERC20 {
    // ============================================================
    // IERC20 - Base ERC-20 Interface
    // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol
    // ============================================================

    /// @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 value of tokens in existence.
    function totalSupply() external view returns (uint256);

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

    /// @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);

    /// @dev Moves a `value` amount of tokens from `from` to `to` using the
    /// allowance mechanism. `value` 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 value) external returns (bool);

    // ============================================================
    // IERC20Metadata - ERC-20 Metadata Extension
    // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/extensions/IERC20Metadata.sol
    // ============================================================

    /// @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);

    // ============================================================
    // IERC20Permit - EIP-2612 Permit Extension
    // https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/extensions/IERC20Permit.sol
    // ============================================================

    /// @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);
}