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// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "https://github.com/LayerZero-Labs/solidity-examples/blob/main/contracts/token/oft/v2/BaseOFTV2.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

/*
    Chain Information:
    LayerZero Optimism Goerli
        chainId: 10132
        endpoint: 0xae92d5aD7583AD66E49A0c67BAd18F6ba52dDDc1
    LayerZero Goerli
        chainId: 10121
        endpoint: 0xbfD2135BFfbb0B5378b56643c2Df8a87552Bfa23

[     
            {         
                "refundAddress": "0x9Eb404FA6a9ad4bF45f20be8f07a16C491629486",         
                "zroPaymentAddress": "0x0",
                "adapterParams": ""0x0002000000000000000000000000000000000000000000000000000000000003d0900000000000000000000000000000000000000000000000000000000000000000c5e31322429453e6d196c34fb16b88edc2a58082 
            } 
        ]

{0x9Eb404FA6a9ad4bF45f20be8f07a16C491629486,0x0,0x0002000000000000000000000000000000000000000000000000000000000003d0900000000000000000000000000000000000000000000000000000000000000000c5e31322429453e6d196c34fb16b88edc2a58082}

Note: If providedGasLimit >= minGasLimit, Fail: "LZApp: gas limit is too low", 
        where providedGasLimit is _getGasLimit(_adapterParams) and minGasLimit is minDstGasLimit
*/

contract ProxyOFTV2 is BaseOFTV2 {
    using SafeERC20 for IERC20;
    IERC20 internal immutable innerToken;
    uint internal immutable ld2sdRate;
    // total amount is transferred from this chain to other chains, ensuring the total is less than uint64.max in sd
    uint public outboundAmount;

constructor(address _token, uint8 _sharedDecimals, address _lzEndpoint) BaseOFTV2(_sharedDecimals, _lzEndpoint) {
        innerToken = IERC20(_token);

(bool success, bytes memory data) = _token.staticcall(
            abi.encodeWithSignature("decimals()")
        );
        require(success, "ProxyOFT: failed to get token decimals");
        uint8 decimals = abi.decode(data, (uint8));

require(_sharedDecimals <= decimals, "ProxyOFT: sharedDecimals must be <= decimals");
        ld2sdRate = 10 ** (decimals - _sharedDecimals);
    }

/************************************************************************
    * public functions
    ************************************************************************/
    function circulatingSupply() public view virtual override returns (uint) {
        return innerToken.totalSupply() - outboundAmount;
    }

function token() public view virtual override returns (address) {
        return address(innerToken);
    }

/************************************************************************
    * internal functions
    ************************************************************************/
    function _debitFrom(address _from, uint16, bytes32, uint _amount) internal virtual override returns (uint) {
        require(_from == _msgSender(), "ProxyOFT: owner is not send caller");

_amount = _transferFrom(_from, address(this), _amount);

// _amount still may have dust if the token has transfer fee, then give the dust back to the sender
        (uint amount, uint dust) = _removeDust(_amount);
        if (dust > 0) innerToken.safeTransfer(_from, dust);

// check total outbound amount
        outboundAmount += amount;
        uint cap = _sd2ld(type(uint64).max);
        require(cap >= outboundAmount, "ProxyOFT: outboundAmount overflow");

return amount;
    }

function _creditTo(uint16, address _toAddress, uint _amount) internal virtual override returns (uint) {
        outboundAmount -= _amount;

// tokens are already in this contract, so no need to transfer
        if (_toAddress == address(this)) {
            return _amount;
        }

return _transferFrom(address(this), _toAddress, _amount);
    }

function _ld2sdRate() internal view virtual override returns (uint) {
        return ld2sdRate;
    }
}