// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

/* Library Imports */
import { Predeploys } from "../libraries/Predeploys.sol";

/* Contract Imports */
import { OptimismMintableERC20 } from "../universal/OptimismMintableERC20.sol";

/**
 * @title BVM_ETH
 * @dev The ETH predeploy provides an ERC20 interface for ETH deposited to Layer 2. Note that
 * unlike on Layer 1, Layer 2 accounts do not have a balance field.
 */
contract BVM_ETH is OptimismMintableERC20 {
    /***************
     * Constructor *
     ***************/

    constructor()
    OptimismMintableERC20(Predeploys.L2_STANDARD_BRIDGE, address(0), "Ether", "WETH")
    {}

    function mint(address _to, uint256 _amount)
        public
        virtual
        override
    {
        revert("BVM_ETH: mint is disabled by normal contract calling. BVM_ETH mint can only be triggered in deposit transaction execution, similar to MNT mint on L2.");
    }

    /**
 * @notice A modifier that only allows the L2_TO_L1_MESSAGE_PASSER to call
     */
    modifier onlyL2Passer() {
        require(msg.sender == Predeploys.L2_TO_L1_MESSAGE_PASSER, "OptimismMintableERC20: only L2MessagePasser can burn");
        _;
    }

    /**
    * @notice Allows the StandardBridge on this network to burn tokens.
     *
     * @param _from   Address to burn tokens from.
     * @param _amount Amount of tokens to burn.
     */
    function burn(address _from, uint256 _amount)
        external
        virtual
        override
        onlyL2Passer
    {
        _burn(_from, _amount);
        emit Burn(_from, _amount);
    }
}