'use strict';

const util = require('util');

const db = require('../database');
const plugins = require('../plugins');

const rewards = module.exports;

rewards.checkConditionAndRewardUser = async function (uid, condition, method) {
	const isActive = await isConditionActive(condition);
	if (!isActive) {
		return;
	}
	const ids = await getIDsByCondition(condition);
	let rewardData = await getRewardDataByIDs(ids);
	rewardData = await filterCompletedRewards(uid, rewardData);
	rewardData = rewardData.filter(Boolean);
	if (!rewardData || !rewardData.length) {
		return;
	}
	const eligible = await Promise.all(rewardData.map(reward => checkCondition(reward, method)));
	const eligibleRewards = rewardData.filter((reward, index) => eligible[index]);
	await giveRewards(uid, eligibleRewards);
};

async function isConditionActive(condition) {
	return await db.isSetMember('conditions:active', condition);
}

async function getIDsByCondition(condition) {
	return await db.getSetMembers('condition:' + condition + ':rewards');
}

async function filterCompletedRewards(uid, rewards) {
	const data = await db.getSortedSetRangeByScoreWithScores('uid:' + uid + ':rewards', 0, -1, 1, '+inf');
	const userRewards = {};

	data.forEach(function (obj) {
		userRewards[obj.value] = parseInt(obj.score, 10);
	});

	return rewards.filter(function (reward) {
		if (!reward) {
			return false;
		}

		const claimable = parseInt(reward.claimable, 10);
		return claimable === 0 || (!userRewards[reward.id] || userRewards[reward.id] < reward.claimable);
	});
}

async function getRewardDataByIDs(ids) {
	return await db.getObjects(ids.map(id => 'rewards:id:' + id));
}

async function getRewardsByRewardData(rewards) {
	return await db.getObjects(rewards.map(reward => 'rewards:id:' + reward.id + ':rewards'));
}

async function checkCondition(reward, method) {
	if (method.constructor && method.constructor.name !== 'AsyncFunction') {
		method = util.promisify(method);
	}
	const value = await method();
	const bool = await plugins.fireHook('filter:rewards.checkConditional:' + reward.conditional, { left: value, right: reward.value });
	return bool;
}

async function giveRewards(uid, rewards) {
	const rewardData = await getRewardsByRewardData(rewards);
	await Promise.all(rewards.map(async function (reward) {
		plugins.fireHook('action:rewards.award:' + reward.rid, { uid: uid, reward: rewardData[rewards.indexOf(reward)] });
		await db.sortedSetIncrBy('uid:' + uid + ':rewards', 1, reward.id);
	}));
}

require('../promisify')(rewards);