// SPDX-License-Identifier: AGPLv3
pragma solidity >= 0.8.0;

import { ISuperfluid } from "./ISuperfluid.sol";
import { ISuperfluidToken } from "./ISuperfluidToken.sol";
import { TokenInfo } from "../tokens/TokenInfo.sol";
import { IERC777 } from "@openzeppelin/contracts/token/ERC777/IERC777.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/**
 * @title Super token (Superfluid Token + ERC20 + ERC777) interface
 * @author Superfluid
 */
interface ISuperToken is ISuperfluidToken, TokenInfo, IERC20, IERC777 {

    /**
     * @dev Initialize the contract
     */
    function initialize(
        IERC20 underlyingToken,
        uint8 underlyingDecimals,
        string calldata n,
        string calldata s
    ) external;

    /**************************************************************************
    * TokenInfo & ERC777
    *************************************************************************/

    /**
     * @dev Returns the name of the token.
     */
    function name() external view override(IERC777, TokenInfo) returns (string memory);

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() external view override(IERC777, TokenInfo) returns (string memory);

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: SuperToken always uses 18 decimals.
     *
     * Note: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() external view override(TokenInfo) returns (uint8);

    /**************************************************************************
    * ERC20 & ERC777
    *************************************************************************/

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() external view override(IERC777, IERC20) returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by an account (`owner`).
     */
    function balanceOf(address account) external view override(IERC777, IERC20) returns(uint256 balance);

    /**************************************************************************
    * ERC20
    *************************************************************************/

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * @return Returns Success a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external override(IERC20) returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     *         allowed to spend on behalf of `owner` through {transferFrom}. This is
     *         zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external override(IERC20) view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * @return Returns Success a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external override(IERC20) returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     *         allowance mechanism. `amount` is then deducted from the caller's
     *         allowance.
     *
     * @return Returns Success a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external override(IERC20) returns (bool);

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) external returns (bool);

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
     function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool);

    /**************************************************************************
    * ERC777
    *************************************************************************/

    /**
     * @dev Returns the smallest part of the token that is not divisible. This
     *         means all token operations (creation, movement and destruction) must have
     *         amounts that are a multiple of this number.
     *
     * For super token contracts, this value is 1 always
     */
    function granularity() external view override(IERC777) returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * @dev If send or receive hooks are registered for the caller and `recipient`,
     *      the corresponding functions will be called with `data` and empty
     *      `operatorData`. See {IERC777Sender} and {IERC777Recipient}.
     *
     * Emits a {Sent} event.
     *
     * Requirements
     *
     * - the caller must have at least `amount` tokens.
     * - `recipient` cannot be the zero address.
     * - if `recipient` is a contract, it must implement the {IERC777Recipient}
     * interface.
     */
    function send(address recipient, uint256 amount, bytes calldata data) external override(IERC777);

    /**
     * @dev Destroys `amount` tokens from the caller's account, reducing the
     * total supply.
     *
     * If a send hook is registered for the caller, the corresponding function
     * will be called with `data` and empty `operatorData`. See {IERC777Sender}.
     *
     * Emits a {Burned} event.
     *
     * Requirements
     *
     * - the caller must have at least `amount` tokens.
     */
    function burn(uint256 amount, bytes calldata data) external override(IERC777);

    /**
     * @dev Returns true if an account is an operator of `tokenHolder`.
     * Operators can send and burn tokens on behalf of their owners. All
     * accounts are their own operator.
     *
     * See {operatorSend} and {operatorBurn}.
     */
    function isOperatorFor(address operator, address tokenHolder) external override(IERC777) view returns (bool);

    /**
     * @dev Make an account an operator of the caller.
     *
     * See {isOperatorFor}.
     *
     * Emits an {AuthorizedOperator} event.
     *
     * Requirements
     *
     * - `operator` cannot be calling address.
     */
    function authorizeOperator(address operator) external override(IERC777);

    /**
     * @dev Revoke an account's operator status for the caller.
     *
     * See {isOperatorFor} and {defaultOperators}.
     *
     * Emits a {RevokedOperator} event.
     *
     * Requirements
     *
     * - `operator` cannot be calling address.
     */
    function revokeOperator(address operator) external override(IERC777);

    /**
     * @dev Returns the list of default operators. These accounts are operators
     * for all token holders, even if {authorizeOperator} was never called on
     * them.
     *
     * This list is immutable, but individual holders may revoke these via
     * {revokeOperator}, in which case {isOperatorFor} will return false.
     */
    function defaultOperators() external override(IERC777) view returns (address[] memory);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient`. The caller must
     * be an operator of `sender`.
     *
     * If send or receive hooks are registered for `sender` and `recipient`,
     * the corresponding functions will be called with `data` and
     * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.
     *
     * Emits a {Sent} event.
     *
     * Requirements
     *
     * - `sender` cannot be the zero address.
     * - `sender` must have at least `amount` tokens.
     * - the caller must be an operator for `sender`.
     * - `recipient` cannot be the zero address.
     * - if `recipient` is a contract, it must implement the {IERC777Recipient}
     * interface.
     */
    function operatorSend(
        address sender,
        address recipient,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external override(IERC777);

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the total supply.
     * The caller must be an operator of `account`.
     *
     * If a send hook is registered for `account`, the corresponding function
     * will be called with `data` and `operatorData`. See {IERC777Sender}.
     *
     * Emits a {Burned} event.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     * - the caller must be an operator for `account`.
     */
    function operatorBurn(
        address account,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external override(IERC777);

    /**************************************************************************
     * SuperToken custom token functions
     *************************************************************************/

    /**
     * @dev Mint new tokens for the account
     *
     * Modifiers:
     *  - onlySelf
     */
    function selfMint(
        address account,
        uint256 amount,
        bytes memory userData
    ) external;

   /**
    * @dev Burn existing tokens for the account
    *
    * Modifiers:
    *  - onlySelf
    */
   function selfBurn(
       address account,
       uint256 amount,
       bytes memory userData
   ) external;

   /**
    * @dev Transfer `amount` tokens from the `sender` to `recipient`.
    * If `spender` isn't the same as `sender`, checks if `spender` has allowance to
    * spend tokens of `sender`.
    *
    * Modifiers:
    *  - onlySelf
    */
   function selfTransferFrom(
        address sender,
        address spender,
        address recipient,
        uint256 amount
   ) external;

   /**
    * @dev Give `spender`, `amount` allowance to spend the tokens of
    * `account`.
    *
    * Modifiers:
    *  - onlySelf
    */
   function selfApproveFor(
        address account,
        address spender,
        uint256 amount
   ) external;

    /**************************************************************************
     * SuperToken extra functions
     *************************************************************************/

    /**
     * @dev Transfer all available balance from `msg.sender` to `recipient`
     */
    function transferAll(address recipient) external;

    /**************************************************************************
     * ERC20 wrapping
     *************************************************************************/

    /**
     * @dev Return the underlying token contract
     * @return tokenAddr Underlying token address
     */
    function getUnderlyingToken() external view returns(address tokenAddr);

    /**
     * @dev Upgrade ERC20 to SuperToken.
     * @param amount Number of tokens to be upgraded (in 18 decimals)
     *
     * NOTE: It will use ´transferFrom´ to get tokens. Before calling this
     * function you should ´approve´ this contract
     */
    function upgrade(uint256 amount) external;

    /**
     * @dev Upgrade ERC20 to SuperToken and transfer immediately
     * @param to The account to received upgraded tokens
     * @param amount Number of tokens to be upgraded (in 18 decimals)
     * @param data User data for the TokensRecipient callback
     *
     * NOTE: It will use ´transferFrom´ to get tokens. Before calling this
     * function you should ´approve´ this contract
     */
    function upgradeTo(address to, uint256 amount, bytes calldata data) external;

    /**
     * @dev Token upgrade event
     * @param account Account where tokens are upgraded to
     * @param amount Amount of tokens upgraded (in 18 decimals)
     */
    event TokenUpgraded(
        address indexed account,
        uint256 amount
    );

    /**
     * @dev Downgrade SuperToken to ERC20.
     * @dev It will call transfer to send tokens
     * @param amount Number of tokens to be downgraded
     */
    function downgrade(uint256 amount) external;

    /**
     * @dev Token downgrade event
     * @param account Account whose tokens are upgraded
     * @param amount Amount of tokens downgraded
     */
    event TokenDowngraded(
        address indexed account,
        uint256 amount
    );

    /**************************************************************************
    * Batch Operations
    *************************************************************************/

    /**
    * @dev Perform ERC20 approve by host contract.
    * @param account The account owner to be approved.
    * @param spender The spender of account owner's funds.
    * @param amount Number of tokens to be approved.
    *
    * Modifiers:
    *  - onlyHost
    */
    function operationApprove(
        address account,
        address spender,
        uint256 amount
    ) external;

    /**
    * @dev Perform ERC20 transfer from by host contract.
    * @param account The account to spend sender's funds.
    * @param spender  The account where the funds is sent from.
    * @param recipient The recipient of thefunds.
    * @param amount Number of tokens to be transferred.
    *
    * Modifiers:
    *  - onlyHost
    */
    function operationTransferFrom(
        address account,
        address spender,
        address recipient,
        uint256 amount
    ) external;

    /**
    * @dev Upgrade ERC20 to SuperToken by host contract.
    * @param account The account to be changed.
    * @param amount Number of tokens to be upgraded (in 18 decimals)
    *
    * Modifiers:
    *  - onlyHost
    */
    function operationUpgrade(address account, uint256 amount) external;

    /**
    * @dev Downgrade ERC20 to SuperToken by host contract.
    * @param account The account to be changed.
    * @param amount Number of tokens to be downgraded (in 18 decimals)
    *
    * Modifiers:
    *  - onlyHost
    */
    function operationDowngrade(address account, uint256 amount) external;


    /**************************************************************************
    * Function modifiers for access control and parameter validations
    *
    * While they cannot be explicitly stated in function definitions, they are
    * listed in function definition comments instead for clarity.
    *
    * NOTE: solidity-coverage not supporting it
    *************************************************************************/

    /// @dev The msg.sender must be the contract itself
    //modifier onlySelf() virtual

}