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/**
 *     NOTICE
 *
 *     The T-REX software is licensed under a proprietary license or the GPL v.3.
 *     If you choose to receive it under the GPL v.3 license, the following applies:
 *     T-REX is a suite of smart contracts implementing the ERC-3643 standard and
 *     developed by Tokeny to manage and transfer financial assets on EVM blockchains
 *
 *     Copyright (C) 2023, Tokeny sàrl.
 *
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 *
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 *
 *     You should have received a copy of the GNU General Public License
 *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

pragma solidity 0.8.17;

interface ICompliance {
    /**
     *  this event is emitted when the Agent has been added on the allowedList of this Compliance.
     *  the event is emitted by the Compliance constructor and by the addTokenAgent function
     *  `_agentAddress` is the address of the Agent to add
     */
    event TokenAgentAdded(address _agentAddress);

    /**
     *  this event is emitted when the Agent has been removed from the agent list of this Compliance.
     *  the event is emitted by the Compliance constructor and by the removeTokenAgent function
     *  `_agentAddress` is the address of the Agent to remove
     */
    event TokenAgentRemoved(address _agentAddress);

    /**
     *  this event is emitted when a token has been bound to the compliance contract
     *  the event is emitted by the bindToken function
     *  `_token` is the address of the token to bind
     */
    event TokenBound(address _token);

    /**
     *  this event is emitted when a token has been unbound from the compliance contract
     *  the event is emitted by the unbindToken function
     *  `_token` is the address of the token to unbind
     */
    event TokenUnbound(address _token);

    /**
     *  @dev adds an agent to the list of token agents
     *  @param _agentAddress address of the agent to be added
     *  Emits a TokenAgentAdded event
     */
    function addTokenAgent(address _agentAddress) external;

    /**
     *  @dev remove Agent from the list of token agents
     *  @param _agentAddress address of the agent to be removed (must be added first)
     *  Emits a TokenAgentRemoved event
     */
    function removeTokenAgent(address _agentAddress) external;

    /**
     *  @dev binds a token to the compliance contract
     *  @param _token address of the token to bind
     *  Emits a TokenBound event
     */
    function bindToken(address _token) external;

    /**
     *  @dev unbinds a token from the compliance contract
     *  @param _token address of the token to unbind
     *  Emits a TokenUnbound event
     */
    function unbindToken(address _token) external;

    /**
     *  @dev function called whenever tokens are transferred
     *  from one wallet to another
     *  this function can update state variables in the compliance contract
     *  these state variables being used by `canTransfer` to decide if a transfer
     *  is compliant or not depending on the values stored in these state variables and on
     *  the parameters of the compliance smart contract
     *  @param _from The address of the sender
     *  @param _to The address of the receiver
     *  @param _amount The amount of tokens involved in the transfer
     */
    function transferred(
        address _from,
        address _to,
        uint256 _amount
    ) external;

    /**
     *  @dev function called whenever tokens are created
     *  on a wallet
     *  this function can update state variables in the compliance contract
     *  these state variables being used by `canTransfer` to decide if a transfer
     *  is compliant or not depending on the values stored in these state variables and on
     *  the parameters of the compliance smart contract
     *  @param _to The address of the receiver
     *  @param _amount The amount of tokens involved in the transfer
     */
    function created(address _to, uint256 _amount) external;

    /**
     *  @dev function called whenever tokens are destroyed
     *  this function can update state variables in the compliance contract
     *  these state variables being used by `canTransfer` to decide if a transfer
     *  is compliant or not depending on the values stored in these state variables and on
     *  the parameters of the compliance smart contract
     *  @param _from The address of the receiver
     *  @param _amount The amount of tokens involved in the transfer
     */
    function destroyed(address _from, uint256 _amount) external;

    /**
     *  @dev Returns true if the Address is in the list of token agents
     *  @param _agentAddress address of this agent
     */
    function isTokenAgent(address _agentAddress) external view returns (bool);

    /**
     *  @dev Returns true if the address given corresponds to a token that is bound with the Compliance contract
     *  @param _token address of the token
     */
    function isTokenBound(address _token) external view returns (bool);

    /**
     *  @dev checks that the transfer is compliant.
     *  default compliance always returns true
     *  READ ONLY FUNCTION, this function cannot be used to increment
     *  counters, emit events, ...
     *  @param _from The address of the sender
     *  @param _to The address of the receiver
     *  @param _amount The amount of tokens involved in the transfer
     */
    function canTransfer(
        address _from,
        address _to,
        uint256 _amount
    ) external view returns (bool);
}