// SPDX-License-Identifier: MIT
pragma solidity ^0.8.23;

import "@openzeppelin/contracts/access/Ownable.sol";

/**
 * @title AereSolverRegistry
 * @notice Allowlist of solvers permitted to call AereSettlement.settle().
 *
 *   Phase 1 (current): owner-curated allowlist. Foundation adds vetted solvers.
 *   Phase 2 (later): permissionless solver entry with bonded stake — anyone
 *     can become a solver by posting an AERE bond; the bond is slashable for
 *     misbehavior (settling at unfavorable clearing prices, censoring orders,
 *     etc). Slashing logic deferred to Phase 2 audit.
 *
 *   Mirror of CoW Protocol's GPv2AllowListAuthentication pattern.
 */
contract AereSolverRegistry is Ownable {
    mapping(address => bool) public isSolver;
    address[] public solvers;

    event SolverAdded(address indexed solver);
    event SolverRemoved(address indexed solver);

    function addSolver(address solver) external onlyOwner {
        require(solver != address(0), "Registry: zero address");
        require(!isSolver[solver], "Registry: already a solver");
        isSolver[solver] = true;
        solvers.push(solver);
        emit SolverAdded(solver);
    }

    function removeSolver(address solver) external onlyOwner {
        require(isSolver[solver], "Registry: not a solver");
        isSolver[solver] = false;
        for (uint256 i = 0; i < solvers.length; i++) {
            if (solvers[i] == solver) {
                solvers[i] = solvers[solvers.length - 1];
                solvers.pop();
                break;
            }
        }
        emit SolverRemoved(solver);
    }

    function solverCount() external view returns (uint256) {
        return solvers.length;
    }
}