'use strict';

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

var db = require('../database');
var user = require('../user');
var notifications = require('../notifications');
var categories = require('../categories');
var privileges = require('../privileges');
var meta = require('../meta');
var utils = require('../../public/src/utils');

module.exports = function(Topics) {

	Topics.getTotalUnread = function(uid, filter, callback) {
		if (!callback) {
			callback = filter;
			filter = '';
		}

		Topics.getUnreadTids(0, uid, 0, 99, filter, function(err, tids) {
			callback(err, tids ? tids.length : 0);
		});
	};

	Topics.getUnreadTopics = function(cid, uid, start, stop, filter, callback) {
		if (!callback) {
			callback = filter;
			filter = '';
		}


		var unreadTopics = {
			showSelect: true,
			nextStart : 0,
			topics: []
		};

		async.waterfall([
			function(next) {
				Topics.getUnreadTids(cid, uid, start, stop, filter, next);
			},
			function(tids, next) {
				if (!tids.length) {
					return next(null, []);
				}
				Topics.getTopicsByTids(tids, uid, next);
			},
			function(topicData, next) {
				if (!Array.isArray(topicData) || !topicData.length) {
					return next(null, unreadTopics);
				}

				unreadTopics.topics = topicData;
				unreadTopics.nextStart = stop + 1;
				next(null, unreadTopics);
			}
		], callback);
	};

	Topics.unreadCutoff = function() {
		return Date.now() - (parseInt(meta.config.unreadCutoff, 10) || 2) * 86400000;
	};

	Topics.getUnreadTids = function(cid, uid, start, stop, filter, callback) {
		if (!callback) {
			callback = filter;
			filter = '';
		}

		uid = parseInt(uid, 10);
		if (uid === 0) {
			return callback(null, []);
		}

		var cutoff = Topics.unreadCutoff();

		async.parallel({
			ignoredCids: function(next) {
				user.getIgnoredCategories(uid, next);
			},
			recentTids: function(next) {
				db.getSortedSetRevRangeByScoreWithScores('topics:recent', 0, -1, '+inf', cutoff, next);
			},
			userScores: function(next) {
				db.getSortedSetRevRangeByScoreWithScores('uid:' + uid + ':tids_read', 0, -1, '+inf', cutoff, next);
			},
			tids_unread: function(next) {
				db.getSortedSetRevRangeWithScores('uid:' + uid + ':tids_unread', 0, -1, next);
			}
		}, function(err, results) {
			if (err) {
				return callback(err);
			}

			if (results.recentTids && !results.recentTids.length && !results.tids_unread.length) {
				return callback(null, []);
			}

			var userRead = {};
			results.userScores.forEach(function(userItem) {
				userRead[userItem.value] = userItem.score;
			});

			results.recentTids = results.recentTids.concat(results.tids_unread);
			results.recentTids.sort(function(a, b) {
				return b.score - a.score;
			});

			var tids = results.recentTids.filter(function(recentTopic) {
				switch (filter) {
					default:
						return !userRead[recentTopic.value] || recentTopic.score > userRead[recentTopic.value];
					case 'new':
						return !userRead[recentTopic.value];
				}
			}).map(function(topic) {
				return topic.value;
			}).filter(function(tid, index, array) {
				return array.indexOf(tid) === index;
			});

			tids = tids.slice(0, 100);

			filterTopics(uid, tids, cid, results.ignoredCids, function(err, tids) {
				if (err) {
					return callback(err);
				}

				if (stop === -1) {
					tids = tids.slice(start);
				} else {
					tids = tids.slice(start, stop + 1);
				}

				callback(null, tids);
			});
		});
	};

	function filterTopics(uid, tids, cid, ignoredCids, callback) {
		if (!Array.isArray(ignoredCids) || !tids.length) {
			return callback(null, tids);
		}

		async.waterfall([
			function(next) {
				privileges.topics.filterTids('read', tids, uid, next);
			},
			function(tids, next) {
				Topics.getTopicsFields(tids, ['tid', 'cid'], next);
			},
			function(topics, next) {
				tids = topics.filter(function(topic) {
					return topic && topic.cid && ignoredCids.indexOf(topic.cid.toString()) === -1 && (!cid || parseInt(cid, 10) === parseInt(topic.cid, 10));
				}).map(function(topic) {
					return topic.tid;
				});
				next(null, tids);
			}
		], callback);
	}

	Topics.pushUnreadCount = function(uid, callback) {
		callback = callback || function() {};

		if (!uid || parseInt(uid, 10) === 0) {
			return callback();
		}
		Topics.getTotalUnread(uid, function(err, count) {
			if (err) {
				return callback(err);
			}

			require('../socket.io').in('uid_' + uid).emit('event:unread.updateCount', count);
			callback();
		});
	};

	Topics.markAsUnreadForAll = function(tid, callback) {
		Topics.markCategoryUnreadForAll(tid, callback);
	};

	Topics.markAsRead = function(tids, uid, callback) {
		callback = callback || function() {};
		if (!Array.isArray(tids) || !tids.length) {
			return callback();
		}

		tids = tids.filter(function(tid, index, array) {
			return tid && utils.isNumber(tid) && array.indexOf(tid) === index;
		});

		if (!tids.length) {
			return callback(null, false);
		}

		async.waterfall([
			function (next) {
				async.parallel({
					topicScores: async.apply(db.sortedSetScores, 'topics:recent', tids),
					userScores: async.apply(db.sortedSetScores, 'uid:' + uid + ':tids_read', tids)
				}, next);
			},
			function (results, next) {
				tids = tids.filter(function(tid, index) {
					return results.topicScores[index] && (!results.userScores[index] || results.userScores[index] < results.topicScores[index]);
				});

				if (!tids.length) {
					return callback(null, false);
				}

				var now = Date.now();
				var scores = tids.map(function() {
					return now;
				});

				async.parallel({
					markRead: async.apply(db.sortedSetAdd, 'uid:' + uid + ':tids_read', scores, tids),
					markUnread: async.apply(db.sortedSetRemove, 'uid:' + uid + ':tids_unread', tids),
					topicData: async.apply(	Topics.getTopicsFields, tids, ['cid'])
				}, next);
			},
			function (results, next) {
				var cids = results.topicData.map(function(topic) {
					return topic && topic.cid;
				}).filter(function(topic, index, array) {
					return topic && array.indexOf(topic) === index;
				});

				categories.markAsRead(cids, uid, next);
			},
			function (next) {
				next(null, true);
			}
		], callback);
	};

	Topics.markAllRead = function(uid, callback) {
		async.waterfall([
			function (next) {
				db.getSortedSetRevRangeByScore('topics:recent', 0, -1, '+inf', Topics.unreadCutoff(), next);
			},
			function (tids, next) {
				for (var i=0; i<tids.length; ++i) {
					Topics.markTopicNotificationsRead(tids[i], uid);
				}
				Topics.markAsRead(tids, uid, next);
			},
			function (markedRead, next) {
				db.delete('uid:' + uid + ':tids_unread', next);
			}
		], callback);
	};

	Topics.markTopicNotificationsRead = function(tid, uid) {
		if (!tid) {
			return;
		}
		user.notifications.getUnreadByField(uid, 'tid', tid, function(err, nids) {
			if (err) {
				return winston.error(err.stack);
			}
			notifications.markReadMultiple(nids, uid, function() {
				user.notifications.pushCount(uid);
			});
		});
	};

	Topics.markCategoryUnreadForAll = function(tid, callback) {
		Topics.getTopicField(tid, 'cid', function(err, cid) {
			if(err) {
				return callback(err);
			}

			categories.markAsUnreadForAll(cid, callback);
		});
	};

	Topics.hasReadTopics = function(tids, uid, callback) {
		if (!parseInt(uid, 10)) {
			return callback(null, tids.map(function() {
				return false;
			}));
		}

		async.parallel({
			recentScores: function(next) {
				db.sortedSetScores('topics:recent', tids, next);
			},
			userScores: function(next) {
				db.sortedSetScores('uid:' + uid + ':tids_read', tids, next);
			},
			tids_unread: function (next) {
				db.sortedSetScores('uid:' + uid + ':tids_unread', tids, next);
			}
		}, function(err, results) {
			if (err) {
				return callback(err);
			}

			var cutoff = Topics.unreadCutoff();
			var result = tids.map(function(tid, index) {
				return !results.tids_unread[index] &&
					(results.recentScores[index] < cutoff ||
					!!(results.userScores[index] && results.userScores[index] >= results.recentScores[index]));
			});

			callback(null, result);
		});
	};

	Topics.hasReadTopic = function(tid, uid, callback) {
		Topics.hasReadTopics([tid], uid, function(err, hasRead) {
			callback(err, Array.isArray(hasRead) && hasRead.length ? hasRead[0] : false);
		});
	};

	Topics.markUnread = function(tid, uid, callback) {
		async.waterfall([
			function (next) {
				Topics.exists(tid, next);
			},
			function (exists, next) {
				if (!exists) {
					return next(new Error('[[error:no-topic]]'));
				}
				db.sortedSetRemove('uid:' + uid + ':tids_read', tid, next);
			},
			function (next) {
				db.sortedSetAdd('uid:' + uid + ':tids_unread', Date.now(), tid, next);
			}
		], callback);
	};

};