// SPDX-License-Identifier: BUSL-1.1
pragma solidity 0.8.29;

import "@openzeppelin/contracts-upgradeable/token/ERC20/ERC20Upgradeable.sol";
import "@openzeppelin/contracts-upgradeable/token/ERC20/extensions/ERC20PermitUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/ReentrancyGuardUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/MulticallUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/utils/PausableUpgradeable.sol";

import "../interfaces/IMintableBurnable.sol";

/**
 * @title Omnichain Token
 * @author USD.AI Foundation
 */
contract OToken is
    IMintableBurnable,
    ERC20Upgradeable,
    ERC20PermitUpgradeable,
    ReentrancyGuardUpgradeable,
    AccessControlUpgradeable,
    MulticallUpgradeable,
    PausableUpgradeable
{
    /*------------------------------------------------------------------------*/
    /* Constants */
    /*------------------------------------------------------------------------*/

    /**
     * @notice Implementation version
     */
    string public constant IMPLEMENTATION_VERSION = "1.1";

    /**
     * @notice Pause admin role
     */
    bytes32 public constant PAUSE_ADMIN_ROLE = keccak256("PAUSE_ADMIN_ROLE");

    /*------------------------------------------------------------------------*/
    /* Immutable State */
    /*------------------------------------------------------------------------*/

    /**
     * @notice OAdapter address
     */
    address private immutable _oAdapter;

    /*------------------------------------------------------------------------*/
    /* Constructor */
    /*------------------------------------------------------------------------*/

    /**
     * @notice Omnichain Token Constructor
     * @param oAdapter_ OAdapter address
     */
    constructor(
        address oAdapter_
    ) {
        _disableInitializers();

        _oAdapter = oAdapter_;
    }

    /*------------------------------------------------------------------------*/
    /* Initializer */
    /*------------------------------------------------------------------------*/

    /**
     * @notice Initialize the contract
     * @param name_ Token name
     * @param symbol_ Token symbol
     * @param admin Default admin address
     */
    function initialize(string memory name_, string memory symbol_, address admin) external initializer {
        __ERC20_init(name_, symbol_);
        __ERC20Permit_init(name_);
        __ReentrancyGuard_init();
        __AccessControl_init();
        __Multicall_init();
        __Pausable_init();

        /* Grant roles */
        _grantRole(DEFAULT_ADMIN_ROLE, admin);
    }

    /*------------------------------------------------------------------------*/
    /* Modifiers */
    /*------------------------------------------------------------------------*/

    /**
     * @notice Modifier to check if the caller is the OAdapter
     */
    modifier onlyOAdapter() {
        require(msg.sender == _oAdapter, "Not authorized");
        _;
    }

    /*------------------------------------------------------------------------*/
    /* Minter API */
    /*------------------------------------------------------------------------*/

    /**
     * @inheritdoc IMintableBurnable
     */
    function mint(address to, uint256 amount) external whenNotPaused onlyOAdapter nonReentrant {
        _mint(to, amount);
    }

    /**
     * @inheritdoc IMintableBurnable
     */
    function burn(address from, uint256 amount) external whenNotPaused onlyOAdapter nonReentrant {
        _burn(from, amount);
    }

    /*------------------------------------------------------------------------*/
    /* Pause Admin API */
    /*------------------------------------------------------------------------*/

    /**
     * @notice Pause the contract
     */
    function pause() external onlyRole(PAUSE_ADMIN_ROLE) {
        _pause();
    }

    /**
     * @notice Unpause the contract
     */
    function unpause() external onlyRole(PAUSE_ADMIN_ROLE) {
        _unpause();
    }
}