// SPDX-License-Identifier: MIT
pragma solidity >=0.7.6 <0.9;

/**
 * FAsset transfer (trailing) fees.
 */
interface ITransferFees {
    /**
     * An agent has claimed their share of transfer fees.
     */
    event TransferFeesClaimed(
        address indexed agentVault,
        address recipient,
        uint256 agentClaimedUBA,
        uint256 poolClaimedUBA,
        uint256 remainingUnclaimedEpochs
    );

    /**
     * Transfer fee will change at timestamp `scheduledAt`.
     */
    event TransferFeeChangeScheduled(
        uint256 nextTransferFeeMillionths,
        uint256 scheduledAt
    );

    /**
     * Claim FAsset transfer fees by an agent.
     * NOTE: may only be called by the agent vault owner
     * @param _agentVault the agent vault for which to claim
     * @param _recipient the account that will receive agent's share of fasset fees
     * @param _maxEpochsToClaim limit the number of epochs to claim, to avoid using too much gas
     * @return _agentClaimedUBA agent's share of total claimed amount in FAsset UBA
     * @return _poolClaimedUBA pool share of total claimed amount in FAsset UBA
     * @return _remainingUnclaimedEpochs nonzero when _maxEpochsToClaim is smaller then the number of unclaimed epochs
     */
    function claimTransferFees(
        address _agentVault,
        address _recipient,
        uint256 _maxEpochsToClaim
    )
        external
        returns (
            uint256 _agentClaimedUBA,
            uint256 _poolClaimedUBA,
            uint256 _remainingUnclaimedEpochs
        );

    function currentTransferFeeEpoch() external view returns (uint256);

    function firstClaimableTransferFeeEpoch() external view returns (uint256);

    function agentUnclaimedTransferFeeEpochs(
        address _agentVault
    ) external view returns (uint256 _first, uint256 _count);

    function agentTransferFeeShare(
        address _agentVault,
        uint256 _maxEpochsToClaim
    ) external view returns (uint256 _feeShareUBA);

    function agentTransferFeeShareForEpoch(
        address _agentVault,
        uint256 _epoch
    ) external view returns (uint256);

    function transferFeeMillionths() external view returns (uint256);

    function setTransferFeeMillionths(
        uint256 _value,
        uint256 _scheduledAt
    ) external;

    ////////////////////////////////////////////////////////////////////////////////////
    // Internal methods

    function fassetTransferFeePaid(uint256 _fee) external;

    function initAgentsMintingHistory(address[] calldata _agentVaults) external;

    ////////////////////////////////////////////////////////////////////////////////////
    // Methods for testing and inspection

    struct TransferFeeSettings {
        uint256 transferFeeMillionths;
        uint256 firstEpochStartTs;
        uint256 epochDuration;
        uint256 maxUnexpiredEpochs;
        uint256 firstClaimableEpoch;
    }

    struct TransferFeeEpochData {
        uint256 startTs;
        uint256 endTs;
        uint256 totalFees;
        uint256 claimedFees;
        bool claimable;
        bool expired;
    }

    struct TransferFeeCalculationDataForAgent {
        uint256 totalFees;
        uint256 cumulativeMinted;
        uint256 totalCumulativeMinted;
        bool claimable;
        bool claimed;
    }

    function transferFeeSettings()
        external
        view
        returns (TransferFeeSettings memory);

    function transferFeeEpochData(
        uint256 _epoch
    ) external view returns (TransferFeeEpochData memory);

    function transferFeeCalculationDataForAgent(
        address _agentVault,
        uint256 _epoch
    ) external view returns (TransferFeeCalculationDataForAgent memory);
}