'use strict';

const async = require('async');
const winston = require('winston');

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

module.exports = function (Groups) {
	Groups.join = async function (groupNames, uid) {
		if (!groupNames) {
			throw new Error('[[error:invalid-data]]');
		}
		if (Array.isArray(groupNames) && !groupNames.length) {
			return;
		}
		if (!Array.isArray(groupNames)) {
			groupNames = [groupNames];
		}

		if (!uid) {
			throw new Error('[[error:invalid-uid]]');
		}

		const [isMembers, exists, isAdmin] = await Promise.all([
			Groups.isMemberOfGroups(uid, groupNames),
			Groups.exists(groupNames),
			user.isAdministrator(uid),
		]);

		const groupsToCreate = groupNames.filter((groupName, index) => groupName && !exists[index]);
		const groupsToJoin = groupNames.filter((groupName, index) => !isMembers[index]);

		if (!groupsToJoin.length) {
			return;
		}
		await createNonExistingGroups(groupsToCreate);

		const promises = [
			db.sortedSetsAdd(groupsToJoin.map(groupName => 'group:' + groupName + ':members'), Date.now(), uid),
			db.incrObjectField(groupsToJoin.map(groupName => 'group:' + groupName), 'memberCount'),
		];
		if (isAdmin) {
			promises.push(db.setsAdd(groupsToJoin.map(groupName => 'group:' + groupName + ':owners'), uid));
		}

		await Promise.all(promises);

		Groups.clearCache(uid, groupsToJoin);

		const groupData = await Groups.getGroupsFields(groupsToJoin, ['name', 'hidden', 'memberCount']);
		const visibleGroups = groupData.filter(groupData => groupData && !groupData.hidden);

		if (visibleGroups.length) {
			await db.sortedSetAdd('groups:visible:memberCount',
				visibleGroups.map(groupData => groupData.memberCount),
				visibleGroups.map(groupData => groupData.name)
			);
		}

		await setGroupTitleIfNotSet(groupsToJoin, uid);

		plugins.fireHook('action:group.join', {
			groupNames: groupsToJoin,
			uid: uid,
		});
	};

	async function createNonExistingGroups(groupsToCreate) {
		if (!groupsToCreate.length) {
			return;
		}

		await async.eachSeries(groupsToCreate, async function (groupName) {
			try {
				await Groups.create({
					name: groupName,
					hidden: 1,
				});
			} catch (err) {
				if (err && err.message !== '[[error:group-already-exists]]') {
					winston.error('[groups.join] Could not create new hidden group', err);
					throw err;
				}
			}
		});
	}

	async function setGroupTitleIfNotSet(groupNames, uid) {
		groupNames = groupNames.filter(groupName => groupName !== 'registered-users' && !Groups.isPrivilegeGroup(groupName));
		if (!groupNames.length) {
			return;
		}

		const currentTitle = await db.getObjectField('user:' + uid, 'groupTitle');
		if (currentTitle || currentTitle === '') {
			return;
		}

		await user.setUserField(uid, 'groupTitle', JSON.stringify(groupNames));
	}
};