'use strict';

var	async = require('async'),
	winston = require('winston'),
	_ = require('underscore'),

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

module.exports = function(Groups) {
	Groups.join = function(groupName, uid, callback) {
		function join() {
			var tasks = [
				async.apply(db.sortedSetAdd, 'group:' + groupName + ':members', Date.now(), uid),
				async.apply(db.incrObjectField, 'group:' + groupName, 'memberCount'),
				async.apply(db.sortedSetIncrBy, 'group:visible:memberCount', 1, groupName)
			];

			async.waterfall([
				function(next) {
					user.isAdministrator(uid, next);
				},
				function(isAdmin, next) {
					if (isAdmin) {
						tasks.push(async.apply(db.setAdd, 'group:' + groupName + ':owners', uid));
					}
					async.parallel(tasks, next);
				},
				function(results, next) {
					user.setGroupTitle(groupName, uid, next);
				},
				function(next) {
					plugins.fireHook('action:group.join', {
						groupName: groupName,
						uid: uid
					});
					next();
				}
			], callback);
		}

		callback = callback || function() {};

		Groups.exists(groupName, function(err, exists) {
			if (err) {
				return callback(err);
			}

			if (exists) {
				return join();
			}

			Groups.create({
				name: groupName,
				description: '',
				hidden: 1
			}, function(err) {
				if (err && err.message !== '[[error:group-already-exists]]') {
					winston.error('[groups.join] Could not create new hidden group: ' + err.message);
					return callback(err);
				}
				join();
			});
		});
	};

	Groups.requestMembership = function(groupName, uid, callback) {
		inviteOrRequestMembership(groupName, uid, 'request', callback);
	};

	Groups.acceptMembership = function(groupName, uid, callback) {
		// Note: For simplicity, this method intentially doesn't check the caller uid for ownership!
		async.waterfall([
			async.apply(db.setRemove, 'group:' + groupName + ':pending', uid),
			async.apply(db.setRemove, 'group:' + groupName + ':invited', uid),
			async.apply(Groups.join, groupName, uid)
		], callback);
	};

	Groups.rejectMembership = function(groupName, uid, callback) {
		// Note: For simplicity, this method intentially doesn't check the caller uid for ownership!
		async.parallel([
			async.apply(db.setRemove, 'group:' + groupName + ':pending', uid),
			async.apply(db.setRemove, 'group:' + groupName + ':invited', uid)
		], callback);
	};

	Groups.invite = function(groupName, uid, callback) {
		inviteOrRequestMembership(groupName, uid, 'invite', callback);
	};

	function inviteOrRequestMembership(groupName, uid, type, callback) {
		if (!parseInt(uid, 10)) {
			return callback(new Error('[[error:not-logged-in]]'));
		}
		var hookName = type === 'invite' ? 'action:group.inviteMember' : 'action:group.requestMembership';
		var set = type === 'invite' ? 'group:' + groupName + ':invited' : 'group:' + groupName + ':pending';

		async.waterfall([
			function(next) {
				async.parallel({
					exists: async.apply(Groups.exists, groupName),
					isMember: async.apply(Groups.isMember, uid, groupName),
					isPending: async.apply(Groups.isPending, uid, groupName),
					isInvited: async.apply(Groups.isInvited, uid, groupName)
				}, next);
			},
			function(checks, next) {
				if (!checks.exists) {
					return next(new Error('[[error:no-group]]'));
				} else if (checks.isMember) {
					return next(new Error('[[error:group-already-member]]'));
				} else if (type === 'invite' && checks.isInvited) {
					return next(new Error('[[error:group-already-invited]]'));
				} else if (type === 'request' && checks.isPending) {
					return next(new Error('[[error:group-already-requested]]'));
				}

				db.setAdd(set, uid, next);
			},
			function(next) {
				plugins.fireHook(hookName, {
					groupName: groupName,
					uid: uid
				});
				next();
			}
		], callback);
	}

	Groups.leave = function(groupName, uid, callback) {
		callback = callback || function() {};

		var tasks = [
			async.apply(db.sortedSetRemove, 'group:' + groupName + ':members', uid),
			async.apply(db.sortedSetIncrBy, 'group:visible:memberCount', -1, groupName),
			async.apply(db.setRemove, 'group:' + groupName + ':owners', uid),
			async.apply(db.decrObjectField, 'group:' + groupName, 'memberCount')
		];

		async.parallel(tasks, function(err) {
			if (err) {
				return callback(err);
			}

			plugins.fireHook('action:group.leave', {
				groupName: groupName,
				uid: uid
			});

			Groups.getGroupFields(groupName, ['hidden', 'memberCount'], function(err, groupData) {
				if (err || !groupData) {
					return callback(err);
				}

				if (parseInt(groupData.hidden, 10) === 1 && parseInt(groupData.memberCount, 10) === 0) {
					Groups.destroy(groupName, callback);
				} else {
					callback();
				}
			});
		});
	};

	Groups.leaveAllGroups = function(uid, callback) {
		async.waterfall([
			function(next) {
				db.getSortedSetRange('groups:createtime', 0, -1, next);
			},
			function(groups, next) {
				async.each(groups, function(groupName, next) {
					async.parallel([
						function(next) {
							Groups.isMember(uid, groupName, function(err, isMember) {
								if (!err && isMember) {
									Groups.leave(groupName, uid, next);
								} else {
									next();
								}
							});
						},
						function(next) {
							Groups.rejectMembership(groupName, uid, next);
						}
					], next);
				}, next);
			}
		], callback);
	};

	Groups.getMembers = function(groupName, start, stop, callback) {
		db.getSortedSetRevRange('group:' + groupName + ':members', start, stop, callback);
	};

	Groups.getMemberUsers = function(groupNames, start, stop, callback) {
		async.map(groupNames, function(groupName, next) {
			Groups.getMembers(groupName, start, stop, function(err, uids) {
				if (err) {
					return next(err);
				}

				user.getMultipleUserFields(uids, ['uid', 'username', 'picture', 'userslug'], next);
			});
		}, callback);
	};

	Groups.getMembersOfGroups = function(groupNames, callback) {
		db.getSortedSetsMembers(groupNames.map(function(name) {
			return 'group:' + name + ':members';
		}), callback);
	};

	Groups.isMember = function(uid, groupName, callback) {
		if (!uid || parseInt(uid, 10) <= 0) {
			return callback(null, false);
		}
		db.isSortedSetMember('group:' + groupName + ':members', uid, callback);
	};

	Groups.isMembers = function(uids, groupName, callback) {
		db.isSortedSetMembers('group:' + groupName + ':members', uids, callback);
	};

	Groups.isMemberOfGroups = function(uid, groups, callback) {
		if (!uid || parseInt(uid, 10) <= 0) {
			return callback(null, groups.map(function() {return false;}));
		}
		groups = groups.map(function(groupName) {
			return 'group:' + groupName + ':members';
		});

		db.isMemberOfSortedSets(groups, uid, callback);
	};

	Groups.getMemberCount = function(groupName, callback) {
		db.getObjectField('group:' + groupName, 'memberCount', function(err, count) {
			if (err) {
				return callback(err);
			}
			callback(null, parseInt(count, 10));
		});
	};

	Groups.isMemberOfGroupList = function(uid, groupListKey, callback) {
		db.getSortedSetRange('group:' + groupListKey + ':members', 0, -1, function(err, groupNames) {
			if (err) {
				return callback(err);
			}
			groupNames = Groups.internals.removeEphemeralGroups(groupNames);
			if (groupNames.length === 0) {
				return callback(null, false);
			}

			Groups.isMemberOfGroups(uid, groupNames, function(err, isMembers) {
				if (err) {
					return callback(err);
				}

				callback(null, isMembers.indexOf(true) !== -1);
			});
		});
	};

	Groups.isMemberOfGroupsList = function(uid, groupListKeys, callback) {
		var sets = groupListKeys.map(function(groupName) {
			return 'group:' + groupName + ':members';
		});

		db.getSortedSetsMembers(sets, function(err, members) {
			if (err) {
				return callback(err);
			}

			var uniqueGroups = _.unique(_.flatten(members));
			uniqueGroups = Groups.internals.removeEphemeralGroups(uniqueGroups);

			Groups.isMemberOfGroups(uid, uniqueGroups, function(err, isMembers) {
				if (err) {
					return callback(err);
				}

				var map = {};

				uniqueGroups.forEach(function(groupName, index) {
					map[groupName] = isMembers[index];
				});

				var result = members.map(function(groupNames) {
					for (var i=0; i<groupNames.length; ++i) {
						if (map[groupNames[i]]) {
							return true;
						}
					}
					return false;
				});

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

	Groups.isMembersOfGroupList = function(uids, groupListKey, callback) {
		db.getSortedSetRange('group:' + groupListKey + ':members', 0, -1, function(err, groupNames) {
			if (err) {
				return callback(err);
			}

			var results = [];
			uids.forEach(function() {
				results.push(false);
			});

			groupNames = Groups.internals.removeEphemeralGroups(groupNames);
			if (groupNames.length === 0) {
				return callback(null, results);
			}

			async.each(groupNames, function(groupName, next) {
				Groups.isMembers(uids, groupName, function(err, isMembers) {
					if (err) {
						return next(err);
					}
					results.forEach(function(isMember, index) {
						if (!isMember && isMembers[index]) {
							results[index] = true;
						}
					});
					next();
				});
			}, function(err) {
				callback(err, results);
			});
		});
	};

	Groups.isInvited = function(uid, groupName, callback) {
		if (!uid) {
			return callback(null, false);
		}
		db.isSetMember('group:' + groupName + ':invited', uid, callback);
	};

	Groups.isPending = function(uid, groupName, callback) {
		if (!uid) {
			return callback(null, false);
		}
		db.isSetMember('group:' + groupName + ':pending', uid, callback);
	};

	Groups.getPending = function(groupName, callback) {
		if (!groupName) {
			return callback(null, []);
		}
		db.getSetMembers('group:' + groupName + ':pending', callback);
	};
};
