// SPDX-License-Identifier: CC0-1.0

pragma solidity 0.8.17;

interface ICompliance {

    /// events

    /**
     *  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);

    /// functions

    /**
     *  @dev binds a token to the compliance contract
     *  @param _token address of the token to bind
     *  This function can be called ONLY by the owner of the compliance contract
     *  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
     *  This function can be called ONLY by the owner of the compliance contract
     *  Emits a TokenUnbound event
     */
    function unbindToken(address _token) external;


    /**
     *  @dev function called whenever tokens are transferred
     *  from one wallet to another
     *  this function can be used to update state variables of the compliance contract
     *  This function can be called ONLY by the token contract bound to the compliance
     *  @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 be used to update state variables of the compliance contract
     *  This function can be called ONLY by the token contract bound to the compliance
     *  @param _to The address of the receiver
     *  @param _amount The amount of tokens involved in the minting
     */
    function created(address _to, uint256 _amount) external;

    /**
     *  @dev function called whenever tokens are destroyed from a wallet
     *  this function can be used to update state variables of the compliance contract
     *  This function can be called ONLY by the token contract bound to the compliance
     *  @param _from The address on which tokens are burnt
     *  @param _amount The amount of tokens involved in the burn
     */
    function destroyed(address _from, uint256 _amount) external;

    /**
     *  @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
     *  This function will call all checks implemented on compliance
     *  If all checks return TRUE, the function returns TRUE
     *  returns FALSE otherwise
     */
    function canTransfer(
        address _from,
        address _to,
        uint256 _amount
    ) external view returns (bool);

    /**
     *  @dev getter for the address of the token bound
     *  returns the address of the token
     */
    function getTokenBound() external view returns (address);
}