// SPDX-License-Identifier: MIT
pragma solidity >=0.8.0;

import "../utils/DAOUpgradeableContract.sol";
import "../utils/NameService.sol";
import "../Interfaces.sol";
import "../governance/GReputation.sol";

/**
 * ClaimersDistribution providers callbacks that can be used by UBIScheme to update when a citizen
 * has claimed.
 * It will distribute GDAO each month pro rata based on number of claims
 */
contract ClaimersDistribution is DAOUpgradeableContract {
	///@notice reputation to distribute each month, will effect next month when set
	uint256 public monthlyReputationDistribution;

	///@notice month number since epoch
	uint256 public currentMonth;

	struct MonthData {
		mapping(address => uint256) claims; //claims per user in month
		uint256 totalClaims; // total claims in month
		uint256 monthlyDistribution; //monthlyReputationDistribution at the time when _updateMonth was called
	}

	///@notice keep track of each month distribution data
	mapping(uint256 => MonthData) public months;

	///@notice marks last month user claimed reputation for
	mapping(address => uint256) public lastMonthClaimed;

	///@notice tracks timestamp of last time user claimed UBI
	mapping(address => uint256) public lastUpdated;

	event ReputationEarned(
		address claimer,
		uint256 month,
		uint256 claims,
		uint256 reputation
	);

	event MonthlyDistributionSet(uint256 reputationAmount);

	function initialize(INameService _ns) public initializer {
		monthlyReputationDistribution = 4000000 ether; //4M as specified in specs
		_updateMonth();
		setDAO(_ns);
	}

	/**
	 * @dev update the monthly reputation distribution. only avatar can do that.
	 * @param newMonthlyReputationDistribution the new reputation amount to distribute
	 */
	function setMonthlyReputationDistribution(
		uint256 newMonthlyReputationDistribution
	) external {
		_onlyAvatar();
		monthlyReputationDistribution = newMonthlyReputationDistribution;
		emit MonthlyDistributionSet(newMonthlyReputationDistribution);
	}

	/**
	 * @dev internal function to switch to new month. records for new month the current monthlyReputationDistribution
	 */
	function _updateMonth() internal {
		uint256 month = block.timestamp / 30 days;
		if (month != currentMonth) {
			//update new month
			currentMonth = month;
			months[currentMonth]
			.monthlyDistribution = monthlyReputationDistribution;
		}
	}

	/**
	 * @dev increase user count of claims if he claimed today. (called automatically by latest version of UBIScheme)
	 * @param _claimer the user to update
	 */
	function updateClaim(address _claimer) external {
		IUBIScheme ubi = IUBIScheme(nameService.getAddress("UBISCHEME"));
		require(
			ubi.hasClaimed(_claimer),
			"ClaimersDistribution: didn't claim today"
		);
		require(
			ubi.currentDay() * 1 days + ubi.periodStart() >
				lastUpdated[_claimer],
			"ClaimersDistribution: already updated"
		);
		_updateMonth();

		lastUpdated[_claimer] = block.timestamp;
		months[currentMonth].claims[_claimer] += 1;
		months[currentMonth].totalClaims += 1;

		uint256 prevMonth = currentMonth - 1;
		if (lastMonthClaimed[_claimer] >= prevMonth) return;
		claimReputation(_claimer);
	}

	/**
	 * @dev helper func
	 * @return number of UBI claims user performed this month
	 */
	function getMonthClaims(address _claimer) public view returns (uint256) {
		return months[currentMonth].claims[_claimer];
	}

	/**
	 * @dev mints reputation to user according to his share in last month claims
	 * @param _claimer the user to distribute reputation to
	 */
	function claimReputation(address _claimer) public {
		uint256 prevMonth = currentMonth - 1;
		uint256 monthlyDist = months[prevMonth].monthlyDistribution;
		uint256 userClaims = months[prevMonth].claims[_claimer];
		if (
			lastMonthClaimed[_claimer] < prevMonth &&
			userClaims > 0 &&
			monthlyDist > 0
		) {
			lastMonthClaimed[_claimer] = prevMonth;
			uint256 userShare = (monthlyDist * userClaims) /
				months[prevMonth].totalClaims;
			if (userShare > 0) {
				GReputation grep = GReputation(
					nameService.getAddress("REPUTATION")
				);
				grep.mint(_claimer, userShare);
				emit ReputationEarned(
					_claimer,
					prevMonth,
					userClaims,
					userShare
				);
			}
		}
	}
}