// SPDX-License-Identifier: MIT

pragma solidity >=0.8.4 <0.9.0;

import "../WitnetUpgradableBase.sol";
import "../base/WitOracleRadonRegistryBase.sol";

/// @title Witnet Request Board EVM-default implementation contract.
/// @notice Contract to bridge requests to Witnet Decentralized Oracle Network.
/// @dev This contract enables posting requests that Witnet bridges will insert into the Witnet network.
/// The result of the requests will be posted back to this contract by the bridge nodes too.
/// @author The Witnet Foundation
abstract contract WitOracleRadonRegistryBaseUpgradable
    is 
        WitOracleRadonRegistryBase,
        WitnetUpgradableBase
{    
    constructor(
            bytes32 _versionTag,
            bool _upgradable
        )
        Ownable(address(msg.sender))
        WitnetUpgradableBase(
            _upgradable,
            _versionTag,
            "io.witnet.proxiable.bytecodes"
        )
    {}
    

    // ================================================================================================================
    // --- Overrides 'Upgradeable' ------------------------------------------------------------------------------------

    function __initializeUpgradableData(bytes memory) virtual override internal {}

    
    // ================================================================================================================
    // --- Overrides 'Ownable2Step' -----------------------------------------------------------------------------------

    /// Returns the address of the pending owner.
    function pendingOwner()
        public view
        virtual override
        returns (address)
    {
        return __bytecodes().pendingOwner;
    }

    /// Returns the address of the current owner.
    function owner()
        public view
        virtual override
        returns (address)
    {
        return __bytecodes().owner;
    }

    /// Starts the ownership transfer of the contract to a new account. Replaces the pending transfer if there is one.
    /// @dev Can only be called by the current owner.
    function transferOwnership(address _newOwner)
        public
        virtual override
        onlyOwner
    {
        __bytecodes().pendingOwner = _newOwner;
        emit OwnershipTransferStarted(owner(), _newOwner);
    }

    /// @dev Transfers ownership of the contract to a new account (`_newOwner`) and deletes any pending owner.
    /// @dev Internal function without access restriction.
    function _transferOwnership(address _newOwner)
        internal
        virtual override
    {
        delete __bytecodes().pendingOwner;
        address _oldOwner = owner();
        if (_newOwner != _oldOwner) {
            __bytecodes().owner = _newOwner;
            emit OwnershipTransferred(_oldOwner, _newOwner);
        }
    }
}