pragma solidity >=0.6.12;

// Author:	Louis Holbrook <dev@holbrook.no> 0826EDA1702D1E87C6E2875121D2E7BB88C2A746
// SPDX-License-Identifier:	AGPL-3.0-or-later
// File-version: 6

interface IAccountsIndex {
	// Address added to store, index in array.
	event AddressAdded(uint256 indexed _idx, address _account);

	// Return number of entries in index.
	function entryCount() external view returns (uint256);

	// Return entry at the spceificed index.
	// Will revert if index is beyond array length.
	// An entry result of 0 means the entry should be skipped, and not count towards entry count.
	function entry(uint256) external view returns (address);

	// Add an entry to the index. Incresases the entry count.
	function add(address) external returns (bool);

	// Verify that the entry exists in the index.
	// Implements ACL
	function have(address) external view returns (bool);

	// Retrieve the timestamp when account was added.
	// If time is not being tracked, a value of 0 should be returned.
	function time(address) external view returns (uint256);
}