[ERC5050] NFTなどのトークン同士で特定のアクションを送受信できる仕組みを理解しよう！

pragma solidity ^0.8.0;

/// @param _address The address of the interactive object
/// @param tokenId The token that is interacting (optional)
struct Object {
    address _address;
    uint256 _tokenId;
}

/// @param selector The bytes4(keccack256()) encoding of the action string
/// @param user The address of the sender
/// @param from The initiating object
/// @param to The receiving object
/// @param state The state controller contract
/// @param data Additional data with no specified format
struct Action {
    bytes4 selector;
    address user;
    Object from;
    Object to;
    address state;
    bytes data;
}

/// @title EIP-5050 Interactive NFTs with Modular Environments
interface IERC5050Sender {
    /// @notice Send an action to the target address
    /// @dev The action's `fromContract` is automatically set to `address(this)`,
    /// and the `from` parameter is set to `msg.sender`.
    /// @param action The action to send
    function sendAction(Action memory action) external payable;

    /// @notice Check if an action is valid based on its hash and nonce
    /// @dev When an action passes through all three possible contracts
    /// (`fromContract`, `to`, and `state`) the `state` contract validates the
    /// action with the initiating `fromContract` using a nonced action hash.
    /// This hash is calculated and saved to storage on the `fromContract` before
    /// action handling is initiated. The `state` contract calculates the hash
    /// and verifies it and nonce with the `fromContract`.
    /// @param _hash The hash to validate
    /// @param _nonce The nonce to validate
    function isValid(bytes32 _hash, uint256 _nonce) external returns (bool);

    /// @notice Retrieve list of actions that can be sent.
    /// @dev Intended for use by off-chain applications to query compatible contracts,
    /// and to advertise functionality in human-readable form.
    function sendableActions() external view returns (string[] memory);

    /// @notice Change or reaffirm the approved address for an action
    /// @dev The zero address indicates there is no approved address.
    ///  Throws unless `msg.sender` is the `_account`, or an authorized
    ///  operator of the `_account`.
    /// @param _account The account of the account-action pair to approve
    /// @param _action The action of the account-action pair to approve
    /// @param _approved The new approved account-action controller
    function approveForAction(
        address _account,
        bytes4 _action,
        address _approved
    ) external returns (bool);

    /// @notice Enable or disable approval for a third party ("operator") to conduct
    ///  all actions on behalf of `msg.sender`
    /// @dev Emits the ApprovalForAll event. The contract MUST allow
    ///  an unbounded number of operators per owner.
    /// @param _operator Address to add to the set of authorized operators
    /// @param _approved True if the operator is approved, false to revoke approval
    function setApprovalForAllActions(address _operator, bool _approved)
        external;

    /// @notice Get the approved address for an account-action pair
    /// @dev Throws if `_tokenId` is not a valid NFT.
    /// @param _account The account of the account-action to find the approved address for
    /// @param _action The action of the account-action to find the approved address for
    /// @return The approved address for this account-action, or the zero address if
    ///  there is none
    function getApprovedForAction(address _account, bytes4 _action)
        external
        view
        returns (address);

    /// @notice Query if an address is an authorized operator for another address
    /// @param _account The address on whose behalf actions are performed
    /// @param _operator The address that acts on behalf of the account
    /// @return True if `_operator` is an approved operator for `_account`, false otherwise
    function isApprovedForAllActions(address _account, address _operator)
        external
        view
        returns (bool);

    /// @dev This emits when an action is sent (`sendAction()`)
    event SendAction(
        bytes4 indexed name,
        address _from,
        address indexed _fromContract,
        uint256 _tokenId,
        address indexed _to,
        uint256 _toTokenId,
        address _state,
        bytes _data
    );

    /// @dev This emits when the approved address for an account-action pair
    ///  is changed or reaffirmed. The zero address indicates there is no
    ///  approved address.
    event ApprovalForAction(
        address indexed _account,
        bytes4 indexed _action,
        address indexed _approved
    );

    /// @dev This emits when an operator is enabled or disabled for an account.
    ///  The operator can conduct all actions on behalf of the account.
    event ApprovalForAllActions(
        address indexed _account,
        address indexed _operator,
        bool _approved
    );
}

interface IERC5050Receiver {
    /// @notice Handle an action
    /// @dev Both the `to` contract and `state` contract are called via
    /// `onActionReceived()`.
    /// @param action The action to handle
    function onActionReceived(Action calldata action, uint256 _nonce)
        external
        payable;

    /// @notice Retrieve list of actions that can be received.
    /// @dev Intended for use by off-chain applications to query compatible contracts,
    /// and to advertise functionality in human-readable form.
    function receivableActions() external view returns (string[] memory);

    /// @dev This emits when a valid action is received.
    event ActionReceived(
        bytes4 indexed name,
        address _from,
        address indexed _fromContract,
        uint256 _tokenId,
        address indexed _to,
        uint256 _toTokenId,
        address _state,
        bytes _data
    );
}

struct Object {
    address _address;
    uint256 _tokenId;
}

struct Action {
    bytes4 selector;
    address user;
    Object from;
    Object to;
    address state;
    bytes data;
}

function sendAction(Action memory action) external payable;

function isValid(bytes32 _hash, uint256 _nonce) external returns (bool);

function sendableActions() external view returns (string[] memory);

function approveForAction(address _account, bytes4 _action, address _approved) external returns (bool);
function setApprovalForAllActions(address _operator, bool _approved) external;

function getApprovedForAction(address _account, bytes4 _action) external view returns (address);
function isApprovedForAllActions(address _account, address _operator) external view returns (bool);

function onActionReceived(Action calldata action, uint256 _nonce) external payable;

function receivableActions() external view returns (string[] memory);

pragma solidity ^0.8.0;

/// @title EIP-5050 Interactive NFTs with Modular Environments
interface IERC5050Interactive {
    function interfaceURI(bytes4 _action) external view returns (string);
}

pragma solidity ^0.8.0;

/// @title EIP-5050 Action Controller
interface IControllable {
    
    /// @notice Enable or disable approval for a third party ("controller") to force
    ///  handling of a given action without performing EIP-5050 validity checks.
    /// @dev Emits the ControllerApproval event. The contract MUST allow
    ///  an unbounded number of controllers per action.
    /// @param _controller Address to add to the set of authorized controllers
    /// @param _action Selector of the action for which the controller is approved / disapproved
    /// @param _approved True if the controller is approved, false to revoke approval
    function setControllerApproval(address _controller, bytes4 _action, bool _approved)
        external;

    /// @notice Enable or disable approval for a third party ("controller") to force
    ///  action handling without performing EIP-5050 validity checks. 
    /// @dev Emits the ControllerApproval event. The contract MUST allow
    ///  an unbounded number of controllers per action.
    /// @param _controller Address to add to the set of authorized controllers
    /// @param _approved True if the controller is approved, false to revoke approval
    function setControllerApprovalForAll(address _controller, bool _approved)
        external;

    /// @notice Query if an address is an authorized controller for a given action.
    /// @param _controller The trusted third party address that can force action handling
    /// @param _action The action selector to query against
    /// @return True if `_controller` is an approved operator for `_account`, false otherwise
    function isApprovedController(address _controller, bytes4 _action)
        external
        view
        returns (bool);
    
    /// @dev This emits when a controller is enabled or disabled for the given
    ///  action. The controller can force `action` handling on the emitting contract, 
    ///  bypassing the standard EIP-5050 validity checks.
    event ControllerApproval(
        address indexed _controller,
        bytes4 indexed _action,
        bool _approved
    );
    
    /// @dev This emits when a controller is enabled or disabled for all actions.
    ///  Disabling all action approval for a controller does not override explicit action
    ///  action approvals. Controller's approved for all actions can force action handling 
    ///  on the emitting contract for any action.
    event ControllerApprovalForAll(
        address indexed _controller,
        bool _approved
    );
}

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.0;

import {ERC5050State, Action} from "./ERC5050State.sol";
import {ERC5050, Action} from "./ERC5050.sol";

struct TokenInfo {
   uint256 health;
   uint256 healthRemaining;
   uint256 power;
   uint256 blockedAt;
   uint256 blockPower;
   uint256 lockedUntilBlock;
   uint256 wins;
   bool hasRegistered;
}

interface IFightGame {
     function getStats(address _contract, uint256 _tokenId) external view returns (TokenInfo);
}

contract FightGame is IFightGame, ERC5050State {
    
    bytes4 constant LIGHT_ATTACK_SELECTOR = bytes4(keccak256("fg.light-attack"));
    bytes4 constant HEAVY_ATTACK_SELECTOR = bytes4(keccak256("fg.heavy-attack"));
    bytes4 constant BLOCK_SELECTOR = bytes4(keccak256("fg.block"));
    
    uint256 constant BLOCK_DECAY = 100;
    uint256 constant LIGHT_ATTACK_DECAY = 200;
    uint256 constant HEAVY_ATTACK_DECAY = 500;
    
    mapping(address => mapping(uint256 => TokenInfo)) state;
    
    constructor()  {
        _registerReceivable("fg.light-attack");
        _registerReceivable("fg.heavy-attack");
        _registerReceivable("fg.block");
    }
    
    function register(address _contract, uint256 _tokenId) external {
        require(msg.sender == ownerOf(_contract, _tokenId), "sender not token owner");
        require(!state[_contract][_tokenId].hasRegistered, "token already registered");
        state[_contract][_tokenId] = TokenInfo(100, 100, 5, 0, 0, 0, true);
    }
    
    function getStats(address _contract, uint256 _tokenId) external view returns (TokenInfo){
        return state[_contract][_tokenId];
    }
    
    function onActionReceived(Action calldata action, uint256 _nonce)
        external
        payable
        override
        onlyReceivableAction(action, _nonce)
    {
        TokenInfo storage from = state[action.from._address][action.from._tokenId];
        require(from.healthRemaining > 0, "health 0");
        require(block.number > from.lockedUntilBlock, "token locked");
        if (action.selector == BLOCK_SELECTOR) {
            from.blockPower = from.power * 3;
            from.blockedAt = block.number;
            from.lockedUntilBlock = block.number + BLOCK_DECAY;
            return;
        }
        
        TokenInfo storage to = state[action.to._address][action.to._tokenId];
        require(to.healthRemaining > 0, "target health 0");
        
        uint256 damage;
        if (action.selector == LIGHT_ATTACK_SELECTOR ) {
            damage = from.power;
            from.lockedUntilBlock = block.number + LIGHT_ATTACK_DECAY;
        }
        
        if (action.selector == HEAVY_ATTACK_SELECTOR) {
            damage = from.power * 3;
            from.lockedUntilBlock = block.number + HEAVY_ATTACK_DECAY;
        }
        if(to.blockedAt + BLOCK_DECAY > block.number) {
            if(to.blockPower >= damage){
                to.blockPower -= damage;
                return;
            }
            damage -= to.blockPower;
        }
        if(to.healthRemaining > damage){
            to.healthRemaining -= damage;
            return;
        }
        
        // Winner gains loser's power and some health 
        from.power += to.power;
        from.healthRemaining += to.power;
        from.wins++;
        to.healthRemaining = 0;
    }
}

contract Fighter is ERC5050, ERC721 {
    
    IFightGame stateContract;
    
    constructor(address _stateContract)  {
        _registerAction("fg.light-attack");
        _registerAction("fg.heavy-attack");
        _registerSendable("fg.block");
        stateContract = IFightGame(_stateContract);
    }
    
    // Update NFT render / metadata based on game stats
    function tokenURICharacterEmoji(uint256 tokenId)
        public
        view
        override
        returns (string memory)
    {
        TokenInfo memory stats = stateContract.getStats(address(this), tokenId);
        if(stats.healthRemaining == 0){
            return unicode"😵";
        }
        if(stats.power > 100){
            return unicode"🦾";
        }
        if(stats.power > 50){
            return unicode"💪";
        }
        if(stats.power > 20){
            return unicode"🤩";
        }
        if(stats.power > 5){
            return unicode"😃";
        }
        return unicode"😀";
    }
}

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.0;

import {ERC5050, Action} from "./ERC5050.sol";

contract Spells is ERC5050, ERC721 {

    bytes4 constant CAST_SELECTOR = bytes4(keccak256("cast"));
    bytes4 constant ATTUNE_SELECTOR = bytes4(keccak256("attune"));

    mapping(uint256 => uint256) spellDust;
    mapping(uint256 => string) attunement;

    constructor() ERC721("Spells", unicode"🔮") {
        _registerSendable("cast");
        _registerReceivable("attune");
    }

    function sendAction(Action memory action)
        external
        payable
        override
        onlySendableAction(action)
    {
        require(
            msg.sender == ownerOf(action.from._tokenId),
            "Spells: invalid sender"
        );
        _sendAction(action);
    }

    function onActionReceived(Action calldata action, uint256 _nonce)
        external
        payable
        override
        onlyReceivableAction(action, _nonce)
    {
        if (action.selector == ATTUNE_SELECTOR) {
            string memory unicodeChar;
            bytes memory _data = action.data;
            assembly {
                // Read unicode character from first 6 bytes (\u5050)
                unicodeChar := shr(208, _data)
            }
            attunement[action.to._tokenId] = unicodeChar;
        }
        // Pass action to state receiver if specified
        _onActionReceived(action, _nonce);
    }

    string[12] private dust = [
        unicode"․",
        unicode"∴",
        unicode"`"
    ];

    string[5] private spells = [
        "Conjuring",
        "Divining",
        "Transforming",
        "Hexing",
        "Banishing"
    ];

    function tokenURI(uint256 tokenId)
        public
        view
        override
        returns (string memory)
    {
        string
            memory out = '<svg xmlns="http://www.w3.org/2000/svg" preserveAspectRatio="xMinYMin meet" viewBox="0 0 400 350"><style>.base { fill: lightyellow; font-family: serif; font-size: 14px; } .chant { font-style: italic;} .dust {font-family: monospace; font-size: 8px; letter-spacing:5px;}.sm{font-size: 10px;} .sigil{font-family: monospace, font-size:13}</style><rect width="100%" height="100%" fill="#171717" /><text x="14" y="24" class="base">';

        out = string.concat(
            out,
            string.concat(spells[_spellType(tokenId)], " Spell"),
            '</text><text x="376" y="336" class="base sigil">',
            attunement[tokenId]
        );
        out = string.concat(out, "</text></svg>");
        string memory json = Base64.encode(
            bytes(
                string(
                    abi.encodePacked(
                        '{"name": "Spell #',
                        Strings.toString(tokenId),
                        '", "description": "Cast spells, attune spells.", "image": "data:image/svg+xml;base64,',
                        Base64.encode(bytes(out)),
                        '"}'
                    )
                )
            )
        );
        return string(abi.encodePacked("data:application/json;base64,", json));
    }

    function _spellType(uint256 tokenId) internal pure returns (uint256) {
        uint256 rand = _random(Strings.toString(tokenId));
        return rand % 6;
    }

    function _random(string memory input) internal pure returns (uint256) {
        return uint256(keccak256(abi.encodePacked(input)));
    }
}

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