// SPDX-License-Identifier: BSL 1.1 - Copyright 2024 MetaLayer Labs Ltd.
pragma solidity 0.8.15;

import { Initializable } from "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

import { Semver } from "src/universal/Semver.sol";
import { AddressAliasHelper } from "src/vendor/AddressAliasHelper.sol";
import { Predeploys } from "src/libraries/Predeploys.sol";
import { Blast, YieldMode, GasMode } from "src/L2/Blast.sol";

/// @custom:predeploy 0x4300000000000000000000000000000000000000
/// @title SharesBase
/// @notice Base contract to track share rebasing and yield reporting.
abstract contract SharesBase is Initializable {
    /// @notice Approved yield reporter.
    address public immutable REPORTER;

    /// @notice Share price. This value can only increase.
    uint256 public price;

    /// @notice Accumulated yield that has not been distributed
    ///         to the share price.
    uint256 public pending;

    /// @notice Reserve extra slots (to a total of 50) in the storage layout for future upgrades.
    ///         A gap size of 48 was chosen here, so that the first slot used in a child contract
    ///         would be a multiple of 50.
    uint256[48] private __gap;

    /// @notice Emitted when a new share price is set after a yield event.
    event NewPrice(uint256 price);

    error InvalidReporter();
    error DistributeFailed(uint256 count, uint256 pending);
    error PriceIsInitialized();

    /// @param _reporter Address of the approved yield reporter.
    constructor(address _reporter) {
        REPORTER = _reporter;
    }

    /// @notice Initializer.
    /// @param _price Initial share price.
    // solhint-disable-next-line func-name-mixedcase
    function __SharesBase_init(uint256 _price) internal onlyInitializing {
        if (price != 0) {
            revert PriceIsInitialized();
        }
        price = _price;
    }

    /// @notice Get the total number of shares. Needs to be
    ///         overridden by the child contract.
    /// @return Total number of shares.
    function count() public view virtual returns (uint256);

    /// @notice Report a yield event and update the share price.
    /// @param value Amount of new yield
    function addValue(uint256 value) external {
        _addValue(value);
    }

    function _addValue(uint256 value) internal virtual {
        if (AddressAliasHelper.undoL1ToL2Alias(msg.sender) != REPORTER) {
            revert InvalidReporter();
        }

        if (value > 0) {
            pending += value;
        }

        _tryDistributePending();
    }

    /// @notice Attempt to distribute pending yields if there
    ///         are sufficient pending yields to increase the
    ///         share price.
    /// @return True if there were sufficient pending yields to
    ///         increase the share price.
    function _tryDistributePending() internal returns (bool) {
        if (pending < count() || count() == 0) {
            return false;
        }

        price += pending / count();
        pending = pending % count();

        emit NewPrice(price);

        return true;
    }
}

/// @custom:predeploy 0x4300000000000000000000000000000000000000
/// @title Shares
/// @notice Integrated EVM contract to manage native ether share
///         rebasing from yield reports.
contract Shares is SharesBase, Semver {
    /// @notice Total number of shares. This value is modified directly
    ///         by the sequencer EVM.
    uint256 private _count;

    /// @notice _reporter Address of approved yield reporter.
    constructor(address _reporter) SharesBase(_reporter) Semver(1, 0, 0) {
        _disableInitializers();
    }

    /// @notice Initializer.
    function initialize(uint256 _price) public initializer {
        __SharesBase_init({ _price: _price });
        Blast(Predeploys.BLAST).configureContract(
            address(this),
            YieldMode.VOID,
            GasMode.VOID,
            address(0xdead) /// don't set a governor
        );
    }

    /// @inheritdoc SharesBase
    function count() public view override returns (uint256) {
        return _count;
    }

    function _addValue(uint256 value) internal override {
        super._addValue(value);

        SharesBase(Predeploys.WETH_REBASING).addValue(value);
    }
}