// SPDX-License-Identifier: MIT LICENSE
// Abstract contract for the full ERC20 Token standard
// https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
pragma solidity ^0.7.6;

interface IERC20 {
    /// @param _owner The address from which the balance will be retrieved
    /// @return balance The balance
    function balanceOf(address _owner) external view returns (uint256 balance);

    /// @notice send `_value` token to `_to` from `msg.sender`
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return success Whether the transfer was successful or not
    function transfer(address _to, uint256 _value)
        external
        returns (bool success);

    /// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
    /// @param _from The address of the sender
    /// @param _to The address of the recipient
    /// @param _value The amount of token to be transferred
    /// @return success Whether the transfer was successful or not
    function transferFrom(
        address _from,
        address _to,
        uint256 _value
    ) external returns (bool success);

    /// @notice `msg.sender` approves `_spender` to spend `_value` tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @param _value The amount of tokens to be approved for transfer
    /// @return success Whether the approval was successful or not
    function approve(address _spender, uint256 _value)
        external
        returns (bool success);

    /// @param _owner The address of the account owning tokens
    /// @param _spender The address of the account able to transfer the tokens
    /// @return remaining Amount of remaining tokens allowed to spent
    function allowance(address _owner, address _spender)
        external
        view
        returns (uint256 remaining);

    // solhint-disable-next-line no-simple-event-func-name
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(
        address indexed _owner,
        address indexed _spender,
        uint256 _value
    );
}
