pragma solidity >=0.6.12;

// Author:	Louis Holbrook <dev@holbrook.no> 0826EDA1702D1E87C6E2875121D2E7BB88C2A746
// SPDX-License-Identifier:	AGPL-3.0-or-later
// File-version: 1

// Methods for swapping tokens for each other.

interface ITokenSwap {
	// Emitted when a new deposit has been made.
	event Deposit(address indexed _token, uint256 _value);

	// Default token used to access the token swap.
	// Returns zero-address if no default token is defined.
	function defaultToken() external returns (address);

	// Add inToken liquidity to the tune of given value. 
	// Requires token approval for the corresponding value.
	// If value is 0, up to the full approval MAY be used for the transfer.
	function deposit(address _inToken, uint256 _value) external returns (uint256);

	// Withdraw pending outToken balance of given value in the pool for the sender.
	// May require token approval for defaultToken if used by contract as exchange for the withdrawal.
	// If value is 0, up to the full approval value MAY be used for the transfer.
	function withdraw(address _outToken, uint256 _value) external returns (uint256);

	// Exchange inToken equalling given value for outToken.
	// Requires token approval for the value of inToken.
	// If value is 0, up to the full approval value MAY be used for the transfer.
	function withdraw(address _outToken, address _inToken, uint256 _value) external returns (uint256);
}