// File: contracts/PWNVault.sol



// SPDX-License-Identifier: GPL-3.0-only
pragma solidity 0.8.4;

import "@pwnfinance/multitoken/contracts/MultiToken.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol";

contract PWNVault is Ownable, IERC721Receiver, IERC1155Receiver {
    using MultiToken for MultiToken.Asset;

    /*----------------------------------------------------------*|
    |*  # VARIABLES & CONSTANTS DEFINITIONS                     *|
    |*----------------------------------------------------------*/

    address public PWN;

    /*----------------------------------------------------------*|
    |*  # MODIFIERS                                             *|
    |*----------------------------------------------------------*/

    modifier onlyPWN() {
        require(msg.sender == PWN, "Caller is not the PWN");
        _;
    }

    /*----------------------------------------------------------*|
    |*  # EVENTS & ERRORS DEFINITIONS                           *|
    |*----------------------------------------------------------*/

    event VaultPull(MultiToken.Asset asset, address indexed origin);
    event VaultPush(MultiToken.Asset asset, address indexed beneficiary);
    event VaultPushFrom(MultiToken.Asset asset, address indexed origin, address indexed beneficiary);


    /*----------------------------------------------------------*|
    |*  # CONSTRUCTOR & FUNCTIONS                               *|
    |*----------------------------------------------------------*/

    /**
     * PWN Vault constructor
     * @dev this contract holds balances of all locked collateral & paid back loan prior to their rightful claims
     * @dev in order for the vault to work it has to have an association with the PWN logic via `.setPWN(PWN.address)`
     */
    constructor() Ownable() IERC1155Receiver() {
    }

    /**
     * pull
     * @dev function accessing an asset and pulling it INTO the vault
     * @dev the function assumes a prior token approval was made with the PWNVault.address to be approved
     * @param _asset An asset construct - for definition see { MultiToken.sol }
     * @return true if successful
     */
    function pull(MultiToken.Asset memory _asset, address _origin) external onlyPWN returns (bool) {
        _asset.transferAssetFrom(_origin, address(this));
        emit VaultPull(_asset, _origin);
        return true;
    }

    /**
     * push
     * @dev function pushing an asset FROM the vault, sending to a defined recipient
     * @dev this is used for claiming a paidback loan or defaulted collateral
     * @param _asset An asset construct - for definition see { MultiToken.sol }
     * @param _beneficiary An address of the recipient of the asset - is set in the PWN logic contract
     * @return true if successful
     */
    function push(MultiToken.Asset memory _asset, address _beneficiary) external onlyPWN returns (bool) {
        _asset.transferAsset(_beneficiary);
        emit VaultPush(_asset, _beneficiary);
        return true;
    }

    /**
     * pushFrom
     * @dev function pushing an asset FROM a lender, sending to a borrower
     * @dev this function assumes prior approval for the asset to be spend by the borrower address
     * @param _asset An asset construct - for definition see { MultiToken.sol }
     * @param _origin An address of the lender who is providing the loan asset
     * @param _beneficiary An address of the recipient of the asset - is set in the PWN logic contract
     * @return true if successful
     */
    function pushFrom(MultiToken.Asset memory _asset, address _origin, address _beneficiary) external onlyPWN returns (bool) {
        _asset.transferAssetFrom(_origin, _beneficiary);
        emit VaultPushFrom(_asset, _origin, _beneficiary);
        return true;
    }

    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * @return `IERC721Receiver.onERC721Received.selector` if transfer is allowed
     */
    function onERC721Received(
        address /*operator*/,
        address /*from*/,
        uint256 /*tokenId*/,
        bytes calldata /*data*/
    ) override external pure returns (bytes4) {
        return IERC721Receiver.onERC721Received.selector;
    }
    
    /**
     * @dev Handles the receipt of a single ERC1155 token type. This function is
     * called at the end of a `safeTransferFrom` after the balance has been updated.
     * To accept the transfer, this must return
     * `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
     * (i.e. 0xf23a6e61, or its own function selector).
     * @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
     */
    function onERC1155Received(
        address /*operator*/,
        address /*from*/,
        uint256 /*id*/,
        uint256 /*value*/,
        bytes calldata /*data*/
    ) override external pure returns (bytes4) {
        return IERC1155Receiver.onERC1155Received.selector;
    }
    
    /**
     * @dev Handles the receipt of a multiple ERC1155 token types. This function
     * is called at the end of a `safeBatchTransferFrom` after the balances have
     * been updated. To accept the transfer(s), this must return
     * `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
     * (i.e. 0xbc197c81, or its own function selector).
     * @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
     */
    function onERC1155BatchReceived(
        address /*operator*/,
        address /*from*/,
        uint256[] calldata /*ids*/,
        uint256[] calldata /*values*/,
        bytes calldata /*data*/
    ) override external pure returns (bytes4) {
        return IERC1155Receiver.onERC1155BatchReceived.selector;
    }

    /**
     * setPWN
     * @dev An essential setup function. Has to be called once PWN contract was deployed
     * @param _address Identifying the PWN contract
     */
    function setPWN(address _address) external onlyOwner {
        PWN = _address;
    }

    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external pure override returns (bool) {
        return
            interfaceId == type(IERC165).interfaceId ||
            interfaceId == type(Ownable).interfaceId ||
            interfaceId == type(IERC721Receiver).interfaceId ||
            interfaceId == type(IERC1155Receiver).interfaceId ||
            interfaceId == this.PWN.selector
                            ^ this.pull.selector
                            ^ this.push.selector
                            ^ this.pushFrom.selector
                            ^ this.setPWN.selector; // PWN Vault

    }
}

// File: @pwnfinance/multitoken/contracts/MultiToken.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";

library MultiToken {

    /**
     * @title Category
     * @dev enum representation Asset category
     */
    enum Category {
        ERC20,
        ERC721,
        ERC1155
    }

    /**
     * @title Asset
     * @param assetAddress Address of the token contract defining the asset
     * @param category Corresponding asset category
     * @param amount Amount of fungible tokens or 0 -> 1
     * @param id TokenID of an NFT or 0
     */
    struct Asset {
        address assetAddress;
        Category category;
        uint256 amount;
        uint256 id;
    }

    /**
     * transferAsset
     * @dev wrapping function for transfer calls on various token interfaces
     * @param _asset Struct defining all necessary context of a token
     * @param _dest Destination address
     */
    function transferAsset(Asset memory _asset, address _dest) internal {
        if (_asset.category == Category.ERC20) {
            IERC20 token = IERC20(_asset.assetAddress);
            token.transfer(_dest, _asset.amount);

        } else if (_asset.category == Category.ERC721) {
            IERC721 token = IERC721(_asset.assetAddress);
            token.safeTransferFrom(address(this), _dest, _asset.id);

        } else if (_asset.category == Category.ERC1155) {
            IERC1155 token = IERC1155(_asset.assetAddress);
            if (_asset.amount == 0) {
                _asset.amount = 1;
            }
            token.safeTransferFrom(address(this), _dest, _asset.id, _asset.amount, "");

        } else {
            revert("MultiToken: Unsupported category");
        }
    }

    /**
     * transferAssetFrom
     * @dev wrapping function for transfer From calls on various token interfaces
     * @param _asset Struct defining all necessary context of a token
     * @param _source Account/address that provided the allowance
     * @param _dest Destination address
     */
    function transferAssetFrom(Asset memory _asset, address _source, address _dest) internal {
        if (_asset.category == Category.ERC20) {
            IERC20 token = IERC20(_asset.assetAddress);
            token.transferFrom(_source, _dest, _asset.amount);

        } else if (_asset.category == Category.ERC721) {
            IERC721 token = IERC721(_asset.assetAddress);
            token.safeTransferFrom(_source, _dest, _asset.id);

        } else if (_asset.category == Category.ERC1155) {
            IERC1155 token = IERC1155(_asset.assetAddress);
            if (_asset.amount == 0) {
                _asset.amount = 1;
            }
            token.safeTransferFrom(_source, _dest, _asset.id, _asset.amount, "");

        } else {
            revert("MultiToken: Unsupported category");
        }
    }

    /**
     * balanceOf
     * @dev wrapping function for checking balances on various token interfaces
     * @param _asset Struct defining all necessary context of a token
     * @param _target Target address to be checked
     */
    function balanceOf(Asset memory _asset, address _target) internal view returns (uint256) {
        if (_asset.category == Category.ERC20) {
            IERC20 token = IERC20(_asset.assetAddress);
            return token.balanceOf(_target);

        } else if (_asset.category == Category.ERC721) {
            IERC721 token = IERC721(_asset.assetAddress);
            if (token.ownerOf(_asset.id) == _target) {
                return 1;
            } else {
                return 0;
            }

        } else if (_asset.category == Category.ERC1155) {
            IERC1155 token = IERC1155(_asset.assetAddress);
            return token.balanceOf(_target, _asset.id);

        } else {
            revert("MultiToken: Unsupported category");
        }
    }

    /**
     * approveAsset
     * @dev wrapping function for approve calls on various token interfaces
     * @param _asset Struct defining all necessary context of a token
     * @param _target Target address to be checked
     */
    function approveAsset(Asset memory _asset, address _target) internal {
        if (_asset.category == Category.ERC20) {
            IERC20 token = IERC20(_asset.assetAddress);
            token.approve(_target, _asset.amount);

        } else if (_asset.category == Category.ERC721) {
            IERC721 token = IERC721(_asset.assetAddress);
            token.approve(_target, _asset.id);

        } else if (_asset.category == Category.ERC1155) {
            IERC1155 token = IERC1155(_asset.assetAddress);
            token.setApprovalForAll(_target, true);

        } else {
            revert("MultiToken: Unsupported category");
        }
    }

    /**
     * isValid
     * @dev checks that assets amount and id is valid in stated category
     * @dev this function don't check that stated category is indeed the category of a contract on a stated address
     * @param _asset Asset that is examined
     * @return True if assets amount and id is valid in stated category
     */
    function isValid(Asset memory _asset) internal pure returns (bool) {
        // ERC20 token has to have id set to 0
        if (_asset.category == Category.ERC20 && _asset.id != 0)
            return false;

        // ERC721 token has to have amount set to 1
        if (_asset.category == Category.ERC721 && _asset.amount != 1)
            return false;

        // Any categories have to have non-zero amount
        if (_asset.amount == 0)
            return false;

        return true;
    }

    /**
     * isSameAs
     * @dev compare two assets, ignoring their amounts
     * @param _asset First asset to examine
     * @param _otherAsset Second asset to examine
     * @return True if both structs represents the same asset
     */
    function isSameAs(Asset memory _asset, Asset memory _otherAsset) internal pure returns (bool) {
        return
            _asset.assetAddress == _otherAsset.assetAddress &&
            _asset.category == _otherAsset.category &&
            _asset.id == _otherAsset.id;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721Receiver.sol)

pragma solidity ^0.8.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC1155/IERC1155Receiver.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC1155/IERC1155Receiver.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev _Available since v3.1._
 */
interface IERC1155Receiver is IERC165 {
    /**
     * @dev Handles the receipt of a single ERC1155 token type. This function is
     * called at the end of a `safeTransferFrom` after the balance has been updated.
     *
     * NOTE: To accept the transfer, this must return
     * `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
     * (i.e. 0xf23a6e61, or its own function selector).
     *
     * @param operator The address which initiated the transfer (i.e. msg.sender)
     * @param from The address which previously owned the token
     * @param id The ID of the token being transferred
     * @param value The amount of tokens being transferred
     * @param data Additional data with no specified format
     * @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
     */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external returns (bytes4);

    /**
     * @dev Handles the receipt of a multiple ERC1155 token types. This function
     * is called at the end of a `safeBatchTransferFrom` after the balances have
     * been updated.
     *
     * NOTE: To accept the transfer(s), this must return
     * `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
     * (i.e. 0xbc197c81, or its own function selector).
     *
     * @param operator The address which initiated the batch transfer (i.e. msg.sender)
     * @param from The address which previously owned the token
     * @param ids An array containing ids of each token being transferred (order and length must match values array)
     * @param values An array containing amounts of each token being transferred (order and length must match ids array)
     * @param data Additional data with no specified format
     * @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
     */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

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

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns 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 returns (bool);

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

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/token/ERC721/IERC721.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/IERC721.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Usage of this method is discouraged, use {safeTransferFrom} whenever possible.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 tokenId
    ) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the caller.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool _approved) external;

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        bytes calldata data
    ) external;
}

// File: @openzeppelin/contracts/token/ERC1155/IERC1155.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC1155/IERC1155.sol)

pragma solidity ^0.8.0;

import "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
        external
        view
        returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);

    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes calldata data
    ) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}