// SPDX-License-Identifier: UNLICENSED

pragma solidity ^0.5.16;

/**
 * @title EIP20NonStandardInterface
 * @dev Version of ERC20 with no return values for `transfer` and `transferFrom`
 *  See https://medium.com/coinmonks/missing-return-value-bug-at-least-130-tokens-affected-d67bf08521ca
 */
interface EIP20NonStandardInterface {
    /**
     * @notice Get the total number of tokens in circulation
     * @return The supply of tokens
     */
    function totalSupply() external view returns (uint256);

    /**
     * @notice Gets the balance of the specified address
     * @param owner The address from which the balance will be retrieved
     * @return The balance
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    ///
    /// !!!!!!!!!!!!!!
    /// !!! NOTICE !!! `transfer` does not return a value, in violation of the ERC-20 specification
    /// !!!!!!!!!!!!!!
    ///

    /**
     * @notice Transfer `amount` tokens from `msg.sender` to `dst`
     * @param dst The address of the destination account
     * @param amount The number of tokens to transfer
     */
    function transfer(address dst, uint256 amount) external;

    ///
    /// !!!!!!!!!!!!!!
    /// !!! NOTICE !!! `transferFrom` does not return a value, in violation of the ERC-20 specification
    /// !!!!!!!!!!!!!!
    ///

    /**
     * @notice Transfer `amount` tokens from `src` to `dst`
     * @param src The address of the source account
     * @param dst The address of the destination account
     * @param amount The number of tokens to transfer
     */
    function transferFrom(
        address src,
        address dst,
        uint256 amount
    ) external;

    /**
     * @notice Approve `spender` to transfer up to `amount` from `src`
     * @dev This will overwrite the approval amount for `spender`
     *  and is subject to issues noted [here](https://eips.ethereum.org/EIPS/eip-20#approve)
     * @param spender The address of the account which may transfer tokens
     * @param amount The number of tokens that are approved
     * @return Whether or not the approval succeeded
     */
    function approve(address spender, uint256 amount) external returns (bool success);

    /**
     * @notice Get the current allowance from `owner` for `spender`
     * @param owner The address of the account which owns the tokens to be spent
     * @param spender The address of the account which may transfer tokens
     * @return The number of tokens allowed to be spent
     */
    function allowance(address owner, address spender) external view returns (uint256 remaining);

    event Transfer(address indexed from, address indexed to, uint256 amount);
    event Approval(address indexed owner, address indexed spender, uint256 amount);
}