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

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import "../../interfaces/IChainAdapter.sol";

contract StellarAdapter is IChainAdapter, AccessControl, ReentrancyGuard {
    using SafeERC20 for IERC20;

    bytes32 public constant BRIDGE_OPERATOR_ROLE = keccak256("BRIDGE_OPERATOR_ROLE");
    bytes32 public constant ORACLE_ROLE = keccak256("ORACLE_ROLE");
    
    bool public isActive;
    
    mapping(bytes32 => BridgeRequest) public bridgeRequests;
    mapping(bytes32 => string) public stellarTxHashes;
    mapping(address => uint256) public nonces;

    event StellarBridgeInitiated(
        bytes32 indexed requestId,
        address indexed sender,
        address indexed token,
        uint256 amount,
        string stellarAccount
    );
    
    event StellarBridgeConfirmed(
        bytes32 indexed requestId,
        string indexed stellarTxHash,
        uint256 ledgerSequence
    );

    constructor(address admin) {
        _grantRole(DEFAULT_ADMIN_ROLE, admin);
        _grantRole(BRIDGE_OPERATOR_ROLE, admin);
        _grantRole(ORACLE_ROLE, admin);
        isActive = true;
    }

    function getChainType() external pure override returns (string memory) {
        return "Stellar";
    }

    function getChainIdentifier() external pure override returns (uint256 chainId, string memory identifier) {
        return (0, "Stellar-Mainnet");
    }

    function validateDestination(bytes calldata destination) external pure override returns (bool) {
        string memory addr = string(destination);
        bytes memory addrBytes = bytes(addr);
        
        // Stellar addresses: G + 55 base32 chars = 56 chars
        if (addrBytes.length != 56) return false;
        if (addrBytes[0] != 'G') return false;
        
        return true;
    }

    function bridge(
        address token,
        uint256 amount,
        bytes calldata destination,
        bytes calldata recipient
    ) external payable override nonReentrant returns (bytes32 requestId) {
        require(isActive, "Adapter inactive");
        require(amount > 0, "Zero amount");
        require(this.validateDestination(destination), "Invalid Stellar address");
        
        string memory stellarAccount = string(destination);
        
        requestId = keccak256(abi.encodePacked(
            msg.sender,
            token,
            amount,
            stellarAccount,
            nonces[msg.sender]++,
            block.timestamp
        ));
        
        if (token == address(0)) {
            require(msg.value >= amount, "Insufficient ETH");
        } else {
            IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
        }
        
        bridgeRequests[requestId] = BridgeRequest({
            sender: msg.sender,
            token: token,
            amount: amount,
            destinationData: destination,
            requestId: requestId,
            status: BridgeStatus.Locked,
            createdAt: block.timestamp,
            completedAt: 0
        });
        
        emit StellarBridgeInitiated(requestId, msg.sender, token, amount, stellarAccount);
        return requestId;
    }

    function confirmStellarTransaction(
        bytes32 requestId,
        string calldata stellarTxHash,
        uint256 ledgerSequence
    ) external onlyRole(ORACLE_ROLE) {
        BridgeRequest storage request = bridgeRequests[requestId];
        require(request.status == BridgeStatus.Locked, "Invalid status");
        
        request.status = BridgeStatus.Confirmed;
        request.completedAt = block.timestamp;
        stellarTxHashes[requestId] = stellarTxHash;
        
        emit StellarBridgeConfirmed(requestId, stellarTxHash, ledgerSequence);
    }

    function getBridgeStatus(bytes32 requestId) 
        external view override returns (BridgeRequest memory) {
        return bridgeRequests[requestId];
    }

    function cancelBridge(bytes32 requestId) external override returns (bool) {
        BridgeRequest storage request = bridgeRequests[requestId];
        require(request.status == BridgeStatus.Pending || request.status == BridgeStatus.Locked, "Cannot cancel");
        require(msg.sender == request.sender, "Not request sender");
        
        if (request.token == address(0)) {
            payable(request.sender).transfer(request.amount);
        } else {
            IERC20(request.token).safeTransfer(request.sender, request.amount);
        }
        
        request.status = BridgeStatus.Cancelled;
        return true;
    }

    function estimateFee(
        address token,
        uint256 amount,
        bytes calldata destination
    ) external pure override returns (uint256 fee) {
        return 100; // 0.00001 XLM (Stellar fees are very low)
    }

    function setIsActive(bool _isActive) external onlyRole(DEFAULT_ADMIN_ROLE) {
        isActive = _isActive;
    }
}
