// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {IRouterClient} from "../ccip/IRouterClient.sol";

/**
 * @title CrossChainFlashVaultCreditReceiver
 * @notice **Source-chain** (or same-chain) CCIP receiver: forwards the first ERC-20 leg to a vault address encoded in `message.data`.
 * @dev Use to **restore flash vault balance** after off-chain or destination-chain settlement. This is not an ERC-3156 repayment
 *      (that must still happen in the flash callback on the borrow chain). `data` = `abi.encode(address vault)`.
 */
contract CrossChainFlashVaultCreditReceiver {
    using SafeERC20 for IERC20;

    IRouterClient public immutable ccipRouter;

    event LiquidityCredited(
        bytes32 indexed messageId,
        uint64 indexed sourceChainSelector,
        address indexed vault,
        address token,
        uint256 amount
    );

    error OnlyRouter();
    error NoTokens();
    error BadData();

    constructor(address ccipRouter_) {
        require(ccipRouter_ != address(0), "CrossChainFlashVaultCreditReceiver: zero router");
        ccipRouter = IRouterClient(ccipRouter_);
    }

    modifier onlyRouter() {
        if (msg.sender != address(ccipRouter)) revert OnlyRouter();
        _;
    }

    function ccipReceive(IRouterClient.Any2EVMMessage calldata message) external onlyRouter {
        _credit(message);
    }

    function _credit(IRouterClient.Any2EVMMessage calldata m) private {
        if (m.tokenAmounts.length == 0) revert NoTokens();
        IRouterClient.TokenAmount calldata ta = m.tokenAmounts[0];
        if (ta.token == address(0) || ta.amount == 0) revert NoTokens();
        address vault = abi.decode(m.data, (address));
        if (vault == address(0)) revert BadData();
        IERC20(ta.token).safeTransfer(vault, ta.amount);
        emit LiquidityCredited(m.messageId, m.sourceChainSelector, vault, ta.token, ta.amount);
    }
}