// 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";

contract Diamond {
    struct Initialization {
        address initContract;
        bytes initData;
    }

    /// @notice This construct a diamond contract
    /// @param _contractOwner the owner of the contract. With default DiamondCutFacet, this is the sole address allowed to make further cuts.
    /// @param _diamondCut the list of facet to add
    /// @param _initializations the list of initialization pair to execute. This allow to setup a contract with multiple level of independent initialization.
    constructor(
        address _contractOwner,
        IDiamondCut.FacetCut[] memory _diamondCut,
        Initialization[] memory _initializations
    ) payable {
        if (_contractOwner != address(0)) {
            LibDiamond.setContractOwner(_contractOwner);
        }

        LibDiamond.diamondCut(_diamondCut, address(0), "");

        for (uint256 i = 0; i < _initializations.length; i++) {
            LibDiamond.initializeDiamondCut(_initializations[i].initContract, _initializations[i].initData);
        }
    }

    // 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.selectorToFacetAndPosition[msg.sig].facetAddress;
        require(facet != address(0), "Diamond: Function does not exist");
        // 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 {}
}