// File: contracts/FlatRateCommission.sol



// Copyright 2021 Cartesi Pte. Ltd.

// SPDX-License-Identifier: Apache-2.0
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

/// @title Interface staking contract
pragma solidity ^0.8.0;

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

contract FlatRateCommission is Fee, Ownable {
    uint256 public immutable feeRaiseTimeout;
    uint256 public immutable maxRaise; // 500 = 5%
    uint256 public constant BASE = 1E4;
    uint256 public rate;
    uint256 public timeoutTimestamp;

    /// @notice Event emmited when a contract is created
    /// @param commission commission charged by the pool
    event FlatRateCommissionCreated(uint256 commission);

    /// @notice event fired when setRate function is called and successful
    /// @param newRate commission charged by the pool effective immediatly
    /// @param timeout timestamp for a new change if raising the fee
    event FlatRateChanged(uint256 newRate, uint256 timeout);

    constructor(
        uint256 _rate,
        uint256 _feeRaiseTimeout,
        uint256 _maxRaise
    ) {
        rate = _rate;
        feeRaiseTimeout = _feeRaiseTimeout;
        maxRaise = _maxRaise;
        emit FlatRateChanged(_rate, timeoutTimestamp);
    }

    /// @notice calculates the total amount of the reward that will be directed to the PoolManager
    /// @return commissionTotal is the amount subtracted from the rewardAmount
    function getCommission(uint256, uint256 rewardAmount)
        external
        view
        override
        returns (uint256)
    {
        uint256 commission = (rewardAmount * rate) / BASE;

        // cap commission to 100%
        return commission > rewardAmount ? rewardAmount : commission;
    }

    /// @notice allows for the poolManager to reduce how much they want to charge for the block production tx
    function setRate(uint256 newRate) external onlyOwner {
        if (newRate > rate) {
            require(
                timeoutTimestamp <= block.timestamp,
                "FlatRateCommission: the fee raise timeout is not expired yet"
            );
            require(
                (newRate - rate) <= maxRaise,
                "FlatRateCommission: the fee raise is over the maximum allowed percentage value"
            );
            timeoutTimestamp = block.timestamp + feeRaiseTimeout;
        }
        rate = newRate;
        emit FlatRateChanged(newRate, timeoutTimestamp);
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: contracts/interfaces/Fee.sol



// Copyright 2021 Cartesi Pte. Ltd.

// SPDX-License-Identifier: Apache-2.0
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
// this file except in compliance with the License. You may obtain a copy of the
// License at http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software distributed
// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
// CONDITIONS OF ANY KIND, either express or implied. See the License for the
// specific language governing permissions and limitations under the License.

pragma solidity >=0.7.0 <0.9.0;

/// @title Calculator of pool owner commission for each block reward
/// @author Danilo Tuler
/// @notice This provides flexibility for different commission models
interface Fee {
    /// @notice calculates the total amount of the reward that will be directed to the pool owner
    /// @return amount of tokens taken by the pool owner as commission
    function getCommission(uint256 posIndex, uint256 rewardAmount)
        external
        view
        returns (uint256);
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}