/****************************************************************************
 * Copyright 2017 EPAM Systems
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ***************************************************************************/

/* global module*/

var Set = {
	empty: function () {
		return {};
	},

	single: function (item) {
		var set = {};
		Set.add(set, item);
		return set;
	},

	size: function (set) {
		var cnt = 0;
		for (var id in set) {
			if (set[id] !== Object.prototype[id])
				cnt++;
		}
		return cnt;
	},

	contains: function (set, v) {
		return typeof (set[v]) !== 'undefined' && set[v] !== Object.prototype[v];
	},

	subset: function (subset, superset) {
		for (var id in subset) {
			if (subset[id] !== Object.prototype[id] && superset[id] !== subset[id])
				return false;
		}
		return true;
	},

	intersection: function (set1, set2) {
		var set = {};
		for (var id in set1) {
			if (set1[id] !== Object.prototype[id] && set2[id] === set1[id])
				Set.add(set, id);
		}
		return set;
	},

	disjoint: function (set1, set2) {
		for (var id in set1) {
			if (set1[id] !== Object.prototype[id] && set2[id] === set1[id])
				return false;
		}
		return true;
	},

	eq: function (set1, set2) {
		return Set.subset(set1, set2) && Set.subset(set2, set1);
	},

	each: function (set, func, context) {
		for (var v in set) {
			if (set[v] !== Object.prototype[v])
				func.call(context, set[v]);
		}
	},

	filter: function (set, func, context) {
		var subset = {};
		for (var v in set) {
			if (set[v] !== Object.prototype[v] && func.call(context, set[v]))
				subset[set[v]] = set[v];
		}
		return subset;
	},

	pick: function (set) {
		for (var v in set) {
			if (set[v] !== Object.prototype[v])
				return set[v];
		}
		return null;
	},

	list: function (set) {
		var list = [];
		for (var v in set) {
			if (set[v] !== Object.prototype[v])
				list.push(set[v]);
		}
		return list;
	},

	add: function (set, item) {
		set[item] = item;
	},

	mergeIn: function (set, other) {
		Set.each(other, function (item) {
			Set.add(set, item);
		});
	},

	remove: function (set, item) {
		var v = set[item];
		delete set[item];
		return v;
	},

	clone: function (other) {
		var set = {};
		Set.mergeIn(set, other);
		return set;
	},

	fromList: function (list) {
		var set = {};
		if (list) {
			for (var i = 0; i < list.length; ++i)
				set[list[i] - 0] = list[i] - 0;
		}
		return set;
	},

	keySetInt: function (map) {
		var set = {};
		map.each(function (id) {
			set[id - 0] = id - 0;
		});
		return set;
	},

	find: function (set, func, context) {
		for (var v in set) {
			if (set[v] !== Object.prototype[v] && func.call(context, set[v]))
				return v;
		}
		return null;
	}
};

module.exports = Set;