// File: contracts/Diamond.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
*
* Implementation of a diamond.
/******************************************************************************/

import { LibDiamond } from "./libraries/LibDiamond.sol";
import { IDiamondCut } from "./interfaces/IDiamondCut.sol";
import { IDiamondLoupe } from  "./interfaces/IDiamondLoupe.sol";
import { IERC173 } from "./interfaces/IERC173.sol";
import { IERC165} from "./interfaces/IERC165.sol";

// When no function exists for function called
error FunctionNotFound(bytes4 _functionSelector);

// This is used in diamond constructor
// more arguments are added to this struct
// this avoids stack too deep errors
struct DiamondArgs {
    address owner;
    address init;
    bytes initCalldata;
}

contract Diamond {    

    constructor(IDiamondCut.FacetCut[] memory _diamondCut, DiamondArgs memory _args) payable {
        LibDiamond.setContractOwner(_args.owner);
        LibDiamond.diamondCut(_diamondCut, _args.init, _args.initCalldata);

        // Code can be added here to perform actions and set state variables.
    }

    // Find facet for function that is called and execute the
    // function if a facet is found and return any value.
    fallback() external payable {
        LibDiamond.DiamondStorage storage ds;
        bytes32 position = LibDiamond.DIAMOND_STORAGE_POSITION;
        // get diamond storage
        assembly {
            ds.slot := position
        }
        // get facet from function selector
        address facet = ds.facetAddressAndSelectorPosition[msg.sig].facetAddress;
        if(facet == address(0)) {
            revert FunctionNotFound(msg.sig);
        }
        // Execute external function from facet using delegatecall and return any value.
        assembly {
            // copy function selector and any arguments
            calldatacopy(0, 0, calldatasize())
             // execute function call using the facet
            let result := delegatecall(gas(), facet, 0, calldatasize(), 0, 0)
            // get any return value
            returndatacopy(0, 0, returndatasize())
            // return any return value or error back to the caller
            switch result
                case 0 {
                    revert(0, returndatasize())
                }
                default {
                    return(0, returndatasize())
                }
        }
    }

    receive() external payable {}
}

// File: contracts/interfaces/IDiamond.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/

interface IDiamond {
    enum FacetCutAction {Add, Replace, Remove}
    // Add=0, Replace=1, Remove=2

    struct FacetCut {
        address facetAddress;
        FacetCutAction action;
        bytes4[] functionSelectors;
    }

    event DiamondCut(FacetCut[] _diamondCut, address _init, bytes _calldata);
}
// File: contracts/interfaces/IDiamondCut.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/

import { IDiamond } from "./IDiamond.sol";

interface IDiamondCut is IDiamond {    

    /// @notice Add/replace/remove any number of functions and optionally execute
    ///         a function with delegatecall
    /// @param _diamondCut Contains the facet addresses and function selectors
    /// @param _init The address of the contract or facet to execute _calldata
    /// @param _calldata A function call, including function selector and arguments
    ///                  _calldata is executed with delegatecall on _init
    function diamondCut(
        FacetCut[] calldata _diamondCut,
        address _init,
        bytes calldata _calldata
    ) external;    
}

// File: contracts/interfaces/IDiamondLoupe.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/

// A loupe is a small magnifying glass used to look at diamonds.
// These functions look at diamonds
interface IDiamondLoupe {
    /// These functions are expected to be called frequently
    /// by tools.

    struct Facet {
        address facetAddress;
        bytes4[] functionSelectors;
    }

    /// @notice Gets all facet addresses and their four byte function selectors.
    /// @return facets_ Facet
    function facets() external view returns (Facet[] memory facets_);

    /// @notice Gets all the function selectors supported by a specific facet.
    /// @param _facet The facet address.
    /// @return facetFunctionSelectors_
    function facetFunctionSelectors(address _facet) external view returns (bytes4[] memory facetFunctionSelectors_);

    /// @notice Get all the facet addresses used by a diamond.
    /// @return facetAddresses_
    function facetAddresses() external view returns (address[] memory facetAddresses_);

    /// @notice Gets the facet that supports the given selector.
    /// @dev If facet is not found return address(0).
    /// @param _functionSelector The function selector.
    /// @return facetAddress_ The facet address.
    function facetAddress(bytes4 _functionSelector) external view returns (address facetAddress_);
}

// File: contracts/interfaces/IERC165.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

interface IERC165 {
    /// @notice Query if a contract implements an interface
    /// @param interfaceId The interface identifier, as specified in ERC-165
    /// @dev Interface identification is specified in ERC-165. This function
    ///  uses less than 30,000 gas.
    /// @return `true` if the contract implements `interfaceID` and
    ///  `interfaceID` is not 0xffffffff, `false` otherwise
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: contracts/interfaces/IERC173.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/// @title ERC-173 Contract Ownership Standard
///  Note: the ERC-165 identifier for this interface is 0x7f5828d0
/* is ERC165 */
interface IERC173 {
    /// @dev This emits when ownership of a contract changes.
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /// @notice Get the address of the owner
    /// @return owner_ The address of the owner.
    function owner() external view returns (address owner_);

    /// @notice Set the address of the new owner of the contract
    /// @dev Set _newOwner to address(0) to renounce any ownership.
    /// @param _newOwner The address of the new owner of the contract
    function transferOwnership(address _newOwner) external;
}

// File: contracts/libraries/LibDiamond.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

/******************************************************************************\
* Author: Nick Mudge <nick@perfectabstractions.com> (https://twitter.com/mudgen)
* EIP-2535 Diamonds: https://eips.ethereum.org/EIPS/eip-2535
/******************************************************************************/
import { IDiamond } from "../interfaces/IDiamond.sol";
import { IDiamondCut } from "../interfaces/IDiamondCut.sol";

// Remember to add the loupe functions from DiamondLoupeFacet to the diamond.
// The loupe functions are required by the EIP2535 Diamonds standard

error NoSelectorsGivenToAdd();
error NotContractOwner(address _user, address _contractOwner);
error NoSelectorsProvidedForFacetForCut(address _facetAddress);
error CannotAddSelectorsToZeroAddress(bytes4[] _selectors);
error NoBytecodeAtAddress(address _contractAddress, string _message);
error IncorrectFacetCutAction(uint8 _action);
error CannotAddFunctionToDiamondThatAlreadyExists(bytes4 _selector);
error CannotReplaceFunctionsFromFacetWithZeroAddress(bytes4[] _selectors);
error CannotReplaceImmutableFunction(bytes4 _selector);
error CannotReplaceFunctionWithTheSameFunctionFromTheSameFacet(bytes4 _selector);
error CannotReplaceFunctionThatDoesNotExists(bytes4 _selector);
error RemoveFacetAddressMustBeZeroAddress(address _facetAddress);
error CannotRemoveFunctionThatDoesNotExist(bytes4 _selector);
error CannotRemoveImmutableFunction(bytes4 _selector);
error InitializationFunctionReverted(address _initializationContractAddress, bytes _calldata);

library LibDiamond {
    bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");

    struct FacetAddressAndSelectorPosition {
        address facetAddress;
        uint16 selectorPosition;
    }

    struct DiamondStorage {
        // function selector => facet address and selector position in selectors array
        mapping(bytes4 => FacetAddressAndSelectorPosition) facetAddressAndSelectorPosition;
        bytes4[] selectors;
        mapping(bytes4 => bool) supportedInterfaces;
        // owner of the contract
        address contractOwner;
    }

    function diamondStorage() internal pure returns (DiamondStorage storage ds) {
        bytes32 position = DIAMOND_STORAGE_POSITION;
        assembly {
            ds.slot := position
        }
    }

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    function setContractOwner(address _newOwner) internal {
        DiamondStorage storage ds = diamondStorage();
        address previousOwner = ds.contractOwner;
        ds.contractOwner = _newOwner;
        emit OwnershipTransferred(previousOwner, _newOwner);
    }

    function contractOwner() internal view returns (address contractOwner_) {
        contractOwner_ = diamondStorage().contractOwner;
    }

    function enforceIsContractOwner() internal view {
        if(msg.sender != diamondStorage().contractOwner) {
            revert NotContractOwner(msg.sender, diamondStorage().contractOwner);
        }        
    }

    event DiamondCut(IDiamondCut.FacetCut[] _diamondCut, address _init, bytes _calldata);

    // Internal function version of diamondCut
    function diamondCut(
        IDiamondCut.FacetCut[] memory _diamondCut,
        address _init,
        bytes memory _calldata
    ) internal {
        for (uint256 facetIndex; facetIndex < _diamondCut.length; facetIndex++) {
            bytes4[] memory functionSelectors = _diamondCut[facetIndex].functionSelectors;
            address facetAddress = _diamondCut[facetIndex].facetAddress;
            if(functionSelectors.length == 0) {
                revert NoSelectorsProvidedForFacetForCut(facetAddress);
            }
            IDiamondCut.FacetCutAction action = _diamondCut[facetIndex].action;
            if (action == IDiamond.FacetCutAction.Add) {
                addFunctions(facetAddress, functionSelectors);
            } else if (action == IDiamond.FacetCutAction.Replace) {
                replaceFunctions(facetAddress, functionSelectors);
            } else if (action == IDiamond.FacetCutAction.Remove) {
                removeFunctions(facetAddress, functionSelectors);
            } else {
                revert IncorrectFacetCutAction(uint8(action));
            }
        }
        emit DiamondCut(_diamondCut, _init, _calldata);
        initializeDiamondCut(_init, _calldata);
    }

    function addFunctions(address _facetAddress, bytes4[] memory _functionSelectors) internal {        
        if(_facetAddress == address(0)) {
            revert CannotAddSelectorsToZeroAddress(_functionSelectors);
        }
        DiamondStorage storage ds = diamondStorage();
        uint16 selectorCount = uint16(ds.selectors.length);                
        enforceHasContractCode(_facetAddress, "LibDiamondCut: Add facet has no code");
        for (uint256 selectorIndex; selectorIndex < _functionSelectors.length; selectorIndex++) {
            bytes4 selector = _functionSelectors[selectorIndex];
            address oldFacetAddress = ds.facetAddressAndSelectorPosition[selector].facetAddress;
            if(oldFacetAddress != address(0)) {
                revert CannotAddFunctionToDiamondThatAlreadyExists(selector);
            }            
            ds.facetAddressAndSelectorPosition[selector] = FacetAddressAndSelectorPosition(_facetAddress, selectorCount);
            ds.selectors.push(selector);
            selectorCount++;
        }
    }

    function replaceFunctions(address _facetAddress, bytes4[] memory _functionSelectors) internal {        
        DiamondStorage storage ds = diamondStorage();
        if(_facetAddress == address(0)) {
            revert CannotReplaceFunctionsFromFacetWithZeroAddress(_functionSelectors);
        }
        enforceHasContractCode(_facetAddress, "LibDiamondCut: Replace facet has no code");
        for (uint256 selectorIndex; selectorIndex < _functionSelectors.length; selectorIndex++) {
            bytes4 selector = _functionSelectors[selectorIndex];
            address oldFacetAddress = ds.facetAddressAndSelectorPosition[selector].facetAddress;
            // can't replace immutable functions -- functions defined directly in the diamond in this case
            if(oldFacetAddress == address(this)) {
                revert CannotReplaceImmutableFunction(selector);
            }
            if(oldFacetAddress == _facetAddress) {
                revert CannotReplaceFunctionWithTheSameFunctionFromTheSameFacet(selector);
            }
            if(oldFacetAddress == address(0)) {
                revert CannotReplaceFunctionThatDoesNotExists(selector);
            }
            // replace old facet address
            ds.facetAddressAndSelectorPosition[selector].facetAddress = _facetAddress;
        }
    }

    function removeFunctions(address _facetAddress, bytes4[] memory _functionSelectors) internal {        
        DiamondStorage storage ds = diamondStorage();
        uint256 selectorCount = ds.selectors.length;
        if(_facetAddress != address(0)) {
            revert RemoveFacetAddressMustBeZeroAddress(_facetAddress);
        }        
        for (uint256 selectorIndex; selectorIndex < _functionSelectors.length; selectorIndex++) {
            bytes4 selector = _functionSelectors[selectorIndex];
            FacetAddressAndSelectorPosition memory oldFacetAddressAndSelectorPosition = ds.facetAddressAndSelectorPosition[selector];
            if(oldFacetAddressAndSelectorPosition.facetAddress == address(0)) {
                revert CannotRemoveFunctionThatDoesNotExist(selector);
            }
            
            
            // can't remove immutable functions -- functions defined directly in the diamond
            if(oldFacetAddressAndSelectorPosition.facetAddress == address(this)) {
                revert CannotRemoveImmutableFunction(selector);
            }
            // replace selector with last selector
            selectorCount--;
            if (oldFacetAddressAndSelectorPosition.selectorPosition != selectorCount) {
                bytes4 lastSelector = ds.selectors[selectorCount];
                ds.selectors[oldFacetAddressAndSelectorPosition.selectorPosition] = lastSelector;
                ds.facetAddressAndSelectorPosition[lastSelector].selectorPosition = oldFacetAddressAndSelectorPosition.selectorPosition;
            }
            // delete last selector
            ds.selectors.pop();
            delete ds.facetAddressAndSelectorPosition[selector];
        }
    }

    function initializeDiamondCut(address _init, bytes memory _calldata) internal {
        if (_init == address(0)) {
            return;
        }
        enforceHasContractCode(_init, "LibDiamondCut: _init address has no code");        
        (bool success, bytes memory error) = _init.delegatecall(_calldata);
        if (!success) {
            if (error.length > 0) {
                // bubble up error
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(error)
                    revert(add(32, error), returndata_size)
                }
            } else {
                revert InitializationFunctionReverted(_init, _calldata);
            }
        }        
    }

    function enforceHasContractCode(address _contract, string memory _errorMessage) internal view {
        uint256 contractSize;
        assembly {
            contractSize := extcodesize(_contract)
        }
        if(contractSize == 0) {
            revert NoBytecodeAtAddress(_contract, _errorMessage);
        }        
    }
}