/**
 *    Copyright (C) 2013 10gen 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 <map>
#include <string>
#include <vector>

#include "mongo/bson/simple_bsonobj_comparator.h"
#include "mongo/db/jsobj.h"
#include "mongo/s/chunk_version.h"

namespace mongo {

/**
 * A KeyRange represents a range over keys of documents in a namespace, qualified by a
 * key pattern which defines the documents that are in the key range.
 *
 * There may be many different expressions to generate the same key fields from a document - the
 * keyPattern tells us these expressions.
 *
 * Ex:
 * DocA : { field : "aaaa" }
 * DocB : { field : "bbb" }
 * DocC : { field : "ccccc" }
 *
 * keyPattern : { field : 1 }
 * minKey : { field : "aaaa" } : Id(DocA)
 * maxKey : { field : "ccccc" } : Id(DocB)
 *
 * contains Id(DocB)
 *
 * keyPattern : { field : "numberofletters" }
 * minKey : { field : 4 } : numberofletters(DocA)
 * maxKey : { field : 5 } : numberofletters(DocC)
 *
 * does not contain numberofletters(DocB)
 */
struct KeyRange {
    KeyRange(const std::string& ns,
             const BSONObj& minKey,
             const BSONObj& maxKey,
             const BSONObj& keyPattern)
        : ns(ns), minKey(minKey), maxKey(maxKey), keyPattern(keyPattern) {}

    KeyRange() {}

    std::string ns;
    BSONObj minKey;
    BSONObj maxKey;
    BSONObj keyPattern;
};

/**
 * Returns true if the point is within the range [inclusiveLower, exclusiveUpper).
 */
bool rangeContains(const BSONObj& inclusiveLower,
                   const BSONObj& exclusiveUpper,
                   const BSONObj& point);

/**
 * Returns true if the bounds specified by [inclusiveLower1, exclusiveUpper1)
 * intersects with the bounds [inclusiveLower2, exclusiveUpper2).
 */
bool rangeOverlaps(const BSONObj& inclusiveLower1,
                   const BSONObj& exclusiveUpper1,
                   const BSONObj& inclusiveLower2,
                   const BSONObj& exclusiveUpper2);

/**
 * Returns -1 if first range is less than the second range, 0 if equal and 1 if
 * greater. The ordering is based on comparing both the min first and then uses
 * the max as the tie breaker.
 */
int compareRanges(const BSONObj& rangeMin1,
                  const BSONObj& rangeMax1,
                  const BSONObj& rangeMin2,
                  const BSONObj& rangeMax2);

/**
 * Represents a cached chunk information on the shard.
 */
class CachedChunkInfo {
public:
    CachedChunkInfo(BSONObj maxKey, ChunkVersion version);

    const BSONObj& getMaxKey() const {
        return _maxKey;
    }

    const ChunkVersion& getVersion() const {
        return _version;
    }

private:
    BSONObj _maxKey;
    ChunkVersion _version;
};

/**
 * A RangeMap is a mapping of an inclusive lower BSON key to an upper key and chunk version, using
 * standard BSON woCompare. The upper bound is exclusive.
 *
 * NOTE: For overlap testing to work correctly, there may be no overlaps present in the map itself.
 */
typedef BSONObjIndexedMap<CachedChunkInfo> RangeMap;

/**
 * A RangeVector is a list of [lower,upper) ranges.
 */
typedef std::vector<std::pair<BSONObj, BSONObj>> RangeVector;

/**
 * Returns the overlap of a range [inclusiveLower, exclusiveUpper) with the provided range map
 * as a vector of ranges from the map.
 */
void getRangeMapOverlap(const RangeMap& ranges,
                        const BSONObj& inclusiveLower,
                        const BSONObj& exclusiveUpper,
                        RangeVector* vector);

/**
 * Returns true if the provided range map has ranges which overlap the provided range
 * [inclusiveLower, exclusiveUpper).
 */
bool rangeMapOverlaps(const RangeMap& ranges,
                      const BSONObj& inclusiveLower,
                      const BSONObj& exclusiveUpper);

/**
 * Returns true if the provided range map exactly contains the provided range
 * [inclusiveLower, exclusiveUpper).
 */
bool rangeMapContains(const RangeMap& ranges,
                      const BSONObj& inclusiveLower,
                      const BSONObj& exclusiveUpper);

/**
 * std::string representation of [inclusiveLower, exclusiveUpper)
 */
std::string rangeToString(const BSONObj& inclusiveLower, const BSONObj& exclusiveUpper);

/**
 * std::string representation of overlapping ranges as a list "[range1),[range2),..."
 */
std::string overlapToString(RangeVector overlap);

}  // namespace mongo
