'use strict';


var async = require('async');
var S = require('string');
var nconf = require('nconf');

var user = require('../user');
var meta = require('../meta');
var topics = require('../topics');
var posts = require('../posts');
var privileges = require('../privileges');
var plugins = require('../plugins');
var helpers = require('./helpers');
var pagination = require('../pagination');
var utils = require('../../public/src/utils');

var topicsController = {};

topicsController.get = function (req, res, callback) {
	var tid = req.params.topic_id;
	var currentPage = parseInt(req.query.page, 10) || 1;
	var pageCount = 1;
	var userPrivileges;
	var settings;

	if ((req.params.post_index && !utils.isNumber(req.params.post_index)) || !utils.isNumber(tid)) {
		return callback();
	}

	async.waterfall([
		function (next) {
			async.parallel({
				privileges: function (next) {
					privileges.topics.get(tid, req.uid, next);
				},
				settings: function (next) {
					user.getSettings(req.uid, next);
				},
				topic: function (next) {
					topics.getTopicData(tid, next);
				},
			}, next);
		},
		function (results, next) {
			if (!results.topic) {
				return callback();
			}

			userPrivileges = results.privileges;

			if (!userPrivileges.read || !userPrivileges['topics:read'] || (parseInt(results.topic.deleted, 10) && !userPrivileges.view_deleted)) {
				return helpers.notAllowed(req, res);
			}

			if (!res.locals.isAPI && (!req.params.slug || results.topic.slug !== tid + '/' + req.params.slug) && (results.topic.slug && results.topic.slug !== tid + '/')) {
				var url = '/topic/' + results.topic.slug;
				if (req.params.post_index) {
					url += '/' + req.params.post_index;
				}
				if (currentPage > 1) {
					url += '?page=' + currentPage;
				}
				return helpers.redirect(res, url);
			}

			settings = results.settings;
			var postCount = parseInt(results.topic.postcount, 10);
			pageCount = Math.max(1, Math.ceil(postCount / settings.postsPerPage));
			results.topic.postcount = postCount;

			if (utils.isNumber(req.params.post_index) && (req.params.post_index < 1 || req.params.post_index > postCount)) {
				return helpers.redirect(res, '/topic/' + req.params.topic_id + '/' + req.params.slug + (req.params.post_index > postCount ? '/' + postCount : ''));
			}

			if (settings.usePagination && (currentPage < 1 || currentPage > pageCount)) {
				return callback();
			}

			var set = 'tid:' + tid + ':posts';
			var reverse = false;
			// `sort` qs has priority over user setting
			var sort = req.query.sort || settings.topicPostSort;
			if (sort === 'newest_to_oldest') {
				reverse = true;
			} else if (sort === 'most_votes') {
				reverse = true;
				set = 'tid:' + tid + ':posts:votes';
			}

			var postIndex = 0;

			req.params.post_index = parseInt(req.params.post_index, 10) || 0;
			if (reverse && req.params.post_index === 1) {
				req.params.post_index = 0;
			}
			if (!settings.usePagination) {
				if (req.params.post_index !== 0) {
					currentPage = 1;
				}
				if (reverse) {
					postIndex = Math.max(0, postCount - (req.params.post_index || postCount) - Math.ceil(settings.postsPerPage / 2));
				} else {
					postIndex = Math.max(0, (req.params.post_index || 1) - Math.ceil(settings.postsPerPage / 2));
				}
			} else if (!req.query.page) {
				var index;
				if (reverse) {
					index = Math.max(0, postCount - (req.params.post_index || postCount) + 2);
				} else {
					index = Math.max(0, req.params.post_index) || 0;
				}

				currentPage = Math.max(1, Math.ceil(index / settings.postsPerPage));
			}

			var start = ((currentPage - 1) * settings.postsPerPage) + postIndex;
			var stop = start + settings.postsPerPage - 1;

			topics.getTopicWithPosts(results.topic, set, req.uid, start, stop, reverse, next);
		},
		function (topicData, next) {
			if (topicData.category.disabled) {
				return callback();
			}

			topics.modifyPostsByPrivilege(topicData, userPrivileges);

			plugins.fireHook('filter:controllers.topic.get', { topicData: topicData, uid: req.uid }, next);
		},
		function (data, next) {
			var breadcrumbs = [
				{
					text: data.topicData.category.name,
					url: nconf.get('relative_path') + '/category/' + data.topicData.category.slug,
				},
				{
					text: data.topicData.title,
				},
			];

			helpers.buildCategoryBreadcrumbs(data.topicData.category.parentCid, function (err, crumbs) {
				if (err) {
					return next(err);
				}
				data.topicData.breadcrumbs = crumbs.concat(breadcrumbs);
				next(null, data.topicData);
			});
		},
		function (topicData, next) {
			function findPost(index) {
				for (var i = 0; i < topicData.posts.length; i += 1) {
					if (parseInt(topicData.posts[i].index, 10) === parseInt(index, 10)) {
						return topicData.posts[i];
					}
				}
			}
			var description = '';
			var postAtIndex = findPost(Math.max(0, req.params.post_index - 1));

			if (postAtIndex && postAtIndex.content) {
				description = S(postAtIndex.content).decodeHTMLEntities().stripTags().s;
			}

			if (description.length > 255) {
				description = description.substr(0, 255) + '...';
			}

			var ogImageUrl = '';
			if (topicData.thumb) {
				ogImageUrl = topicData.thumb;
			} else if (postAtIndex && postAtIndex.user && postAtIndex.user.picture) {
				ogImageUrl = postAtIndex.user.picture;
			} else if (meta.config['og:image']) {
				ogImageUrl = meta.config['og:image'];
			} else if (meta.config['brand:logo']) {
				ogImageUrl = meta.config['brand:logo'];
			} else {
				ogImageUrl = '/logo.png';
			}

			if (typeof ogImageUrl === 'string' && ogImageUrl.indexOf('http') === -1) {
				ogImageUrl = nconf.get('url') + ogImageUrl;
			}

			description = description.replace(/\n/g, ' ');

			res.locals.metaTags = [
				{
					name: 'title',
					content: topicData.titleRaw,
				},
				{
					name: 'description',
					content: description,
				},
				{
					property: 'og:title',
					content: topicData.titleRaw,
				},
				{
					property: 'og:description',
					content: description,
				},
				{
					property: 'og:type',
					content: 'article',
				},
				{
					property: 'og:url',
					content: nconf.get('url') + '/topic/' + topicData.slug + (req.params.post_index ? ('/' + req.params.post_index) : ''),
					noEscape: true,
				},
				{
					property: 'og:image',
					content: ogImageUrl,
					noEscape: true,
				},
				{
					property: 'og:image:url',
					content: ogImageUrl,
					noEscape: true,
				},
				{
					property: 'article:published_time',
					content: utils.toISOString(topicData.timestamp),
				},
				{
					property: 'article:modified_time',
					content: utils.toISOString(topicData.lastposttime),
				},
				{
					property: 'article:section',
					content: topicData.category ? topicData.category.name : '',
				},
			];

			res.locals.linkTags = [
				{
					rel: 'alternate',
					type: 'application/rss+xml',
					href: nconf.get('url') + '/topic/' + tid + '.rss',
				},
			];

			if (topicData.category) {
				res.locals.linkTags.push({
					rel: 'up',
					href: nconf.get('url') + '/category/' + topicData.category.slug,
				});
			}

			next(null, topicData);
		},
	], function (err, data) {
		if (err) {
			return callback(err);
		}

		data.privileges = userPrivileges;
		data.topicStaleDays = parseInt(meta.config.topicStaleDays, 10) || 60;
		data['reputation:disabled'] = parseInt(meta.config['reputation:disabled'], 10) === 1;
		data['downvote:disabled'] = parseInt(meta.config['downvote:disabled'], 10) === 1;
		data['feeds:disableRSS'] = parseInt(meta.config['feeds:disableRSS'], 10) === 1;
		data.bookmarkThreshold = parseInt(meta.config.bookmarkThreshold, 10) || 5;
		data.postEditDuration = parseInt(meta.config.postEditDuration, 10) || 0;
		data.postDeleteDuration = parseInt(meta.config.postDeleteDuration, 10) || 0;
		data.scrollToMyPost = settings.scrollToMyPost;
		data.rssFeedUrl = nconf.get('relative_path') + '/topic/' + data.tid + '.rss';
		data.pagination = pagination.create(currentPage, pageCount, req.query);
		data.pagination.rel.forEach(function (rel) {
			rel.href = nconf.get('url') + '/topic/' + data.slug + rel.href;
			res.locals.linkTags.push(rel);
		});

		req.session.tids_viewed = req.session.tids_viewed || {};
		if (!req.session.tids_viewed[tid] || req.session.tids_viewed[tid] < Date.now() - 3600000) {
			topics.increaseViewCount(tid);
			req.session.tids_viewed[tid] = Date.now();
		}

		if (req.uid) {
			topics.markAsRead([tid], req.uid, function (err, markedRead) {
				if (err) {
					return callback(err);
				}
				if (markedRead) {
					topics.pushUnreadCount(req.uid);
					topics.markTopicNotificationsRead([tid], req.uid);
				}
			});
		}

		res.render('topic', data);
	});
};

topicsController.teaser = function (req, res, next) {
	var tid = req.params.topic_id;

	if (!utils.isNumber(tid)) {
		return next();
	}

	async.waterfall([
		function (next) {
			privileges.topics.can('read', tid, req.uid, next);
		},
		function (canRead, next) {
			if (!canRead) {
				return res.status(403).json('[[error:no-privileges]]');
			}
			topics.getLatestUndeletedPid(tid, next);
		},
		function (pid, next) {
			if (!pid) {
				return res.status(404).json('not-found');
			}
			posts.getPostSummaryByPids([pid], req.uid, { stripTags: false }, next);
		},
	], function (err, posts) {
		if (err) {
			return next(err);
		}

		if (!Array.isArray(posts) || !posts.length) {
			return res.status(404).json('not-found');
		}
		res.json(posts[0]);
	});
};

topicsController.pagination = function (req, res, callback) {
	var tid = req.params.topic_id;
	var currentPage = parseInt(req.query.page, 10) || 1;

	if (!utils.isNumber(tid)) {
		return callback();
	}

	async.parallel({
		privileges: async.apply(privileges.topics.get, tid, req.uid),
		settings: async.apply(user.getSettings, req.uid),
		topic: async.apply(topics.getTopicData, tid),
	}, function (err, results) {
		if (err || !results.topic) {
			return callback(err);
		}

		if (!results.privileges.read || (parseInt(results.topic.deleted, 10) && !results.privileges.view_deleted)) {
			return helpers.notAllowed(req, res);
		}

		var postCount = parseInt(results.topic.postcount, 10);
		var pageCount = Math.max(1, Math.ceil((postCount - 1) / results.settings.postsPerPage));

		var paginationData = pagination.create(currentPage, pageCount);
		paginationData.rel.forEach(function (rel) {
			rel.href = nconf.get('url') + '/topic/' + results.topic.slug + rel.href;
		});

		res.json(paginationData);
	});
};

module.exports = topicsController;