/**
 * Copyright (C) 2017 MongoDB Inc.
 *
 * This program is free software: you can redistribute it and/or  modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * As a special exception, the copyright holders give permission to link the
 * code of portions of this program with the OpenSSL library under certain
 * conditions as described in each individual source file and distribute
 * linked combinations including the program with the OpenSSL library. You
 * must comply with the GNU Affero General Public License in all respects
 * for all of the code used other than as permitted herein. If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so. If you do not
 * wish to do so, delete this exception statement from your version. If you
 * delete this exception statement from all source files in the program,
 * then also delete it in the license file.
 */

#pragma once

#include <set>
#include <string>

#include "mongo/bson/bsonelement.h"
#include "mongo/bson/bsonobj.h"
#include "mongo/bson/bsonobjbuilder.h"
#include "mongo/bson/bsontypes.h"
#include "mongo/stdx/unordered_map.h"

namespace mongo {

/**
 * Represents a set of types or of type aliases in the match language. The set consists of the BSON
 * types as well as "number", which is an alias for all numeric BSON types (NumberInt, NumberLong,
 * and so on).
 */
struct MatcherTypeSet {
    static constexpr StringData kMatchesAllNumbersAlias = "number"_sd;

    // Maps from the set of JSON Schema primitive types to the corresponding BSON types. Excludes
    // "number" since this alias maps to a set of BSON types, and "integer" since it is not
    // supported.
    static const StringMap<BSONType> kJsonSchemaTypeAliasMap;

    /**
     * Given a mapping from string alias to BSON type, creates a MatcherTypeSet from a
     * BSONElement. This BSON alias may either represent a single type (via numerical type code or
     * string alias), or may be an array of types.
     *
     * Returns an error if the element cannot be parsed to a set of types.
     */
    static StatusWith<MatcherTypeSet> parse(BSONElement, const StringMap<BSONType>& aliasMap);

    /**
     * Given a set of string type alias and a mapping from string alias to BSON type, returns the
     * corresponding MatcherTypeSet.
     *
     * Returns an error if any of the string aliases are unknown.
     */
    static StatusWith<MatcherTypeSet> fromStringAliases(std::set<StringData> typeAliases,
                                                        const StringMap<BSONType>& aliasMap);

    /**
     * Constructs an empty type set.
     */
    MatcherTypeSet() = default;

    /* implicit */ MatcherTypeSet(BSONType bsonType) : bsonTypes({bsonType}) {}

    /**
     * Returns true if 'bsonType' is present in the set.
     */
    bool hasType(BSONType bsonType) const {
        return (allNumbers && isNumericBSONType(bsonType)) ||
            bsonTypes.find(bsonType) != bsonTypes.end();
    }

    /**
     * Returns true if this set contains a single type or type alias. For instance, returns true if
     * the set is {"number"} or {"int"}, but not if the set is empty or {"number", "string"}.
     */
    bool isSingleType() const {
        return (allNumbers && bsonTypes.empty()) || (!allNumbers && bsonTypes.size() == 1u);
    }

    bool isEmpty() const {
        return !allNumbers && bsonTypes.empty();
    }

    void toBSONArray(BSONArrayBuilder* builder) const;

    BSONArray toBSONArray() const {
        BSONArrayBuilder builder;
        toBSONArray(&builder);
        return builder.arr();
    }

    bool operator==(const MatcherTypeSet& other) const {
        return allNumbers == other.allNumbers && bsonTypes == other.bsonTypes;
    }

    bool operator!=(const MatcherTypeSet& other) const {
        return !(*this == other);
    }

    bool allNumbers = false;
    std::set<BSONType> bsonTypes;
};

}  // namespace mongo