pragma solidity ^0.8.0;

import {InitializedProxy} from "./InitializedProxy.sol";
import {IImpls} from "../../interfaces/IImpls.sol";

/**
 * @title InitializedProxy
 */
contract TokenVaultExchangeProxy is InitializedProxy {
    constructor(address _settings)
        InitializedProxy(_settings)
    {}

    /**
     * @dev Returns the current implementation address.
     */
    function _implementation()
        internal
        view
        virtual
        override
        returns (address impl)
    {
        return IImpls(settings).exchangeImpl();
    }
}

pragma solidity ^0.8.0;

/**
 * @title SettingStorage
 * @author 0xkongamoto
 */
contract SettingStorage {
    // address of logic contract
    address public immutable settings;

    // ======== Constructor =========

    constructor(address _settings) {
        require(_settings != address(0), "no zero address");
        settings = _settings;
    }
}

pragma solidity ^0.8.0;

import {SettingStorage} from "./SettingStorage.sol";
import {Proxy} from "../openzeppelin/proxy/Proxy.sol";

/**
 * @title InitializedProxy
 * @author 0xkongamoto
 */
contract InitializedProxy is SettingStorage, Proxy {
    // ======== Constructor =========
    constructor(address _settings) SettingStorage(_settings) {}

    /**
     * @dev Returns the current implementation address.
     */
    function _implementation()
        internal
        view
        virtual
        override
        returns (address impl)
    {
        return settings;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 *
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 *
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal virtual {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 { revert(0, returndatasize()) }
            default { return(0, returndatasize()) }
        }
    }

    /**
     * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal view virtual returns (address);

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     *
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal virtual {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback () external payable virtual {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive () external payable virtual {
        _fallback();
    }

    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     *
     * If overriden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {
    }
}

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

interface IImpls {
    function vaultImpl() external view returns (address);

    function stakingImpl() external view returns (address);

    function treasuryImpl() external view returns (address);

    function governmentImpl() external view returns (address);

    function exchangeImpl() external view returns (address);

    function bnftImpl() external view returns (address);
}

{
  "remappings": [],
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  }
}

[{"inputs":[{"internalType":"address","name":"_settings","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"stateMutability":"payable","type":"fallback"},{"inputs":[],"name":"settings","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"stateMutability":"payable","type":"receive"}]