/** @file
 * @brief Return document ids matching a range test on a specified doc value.
 */
/* Copyright 2007,2008,2009,2011 Olly Betts
 * Copyright 2009 Lemur Consulting Ltd
 * Copyright 2010 Richard Boulton
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, see
 * <https://www.gnu.org/licenses/>.
 */

#ifndef XAPIAN_INCLUDED_VALUERANGEPOSTLIST_H
#define XAPIAN_INCLUDED_VALUERANGEPOSTLIST_H

#include "backends/postlist.h"
#include "backends/valuelist.h"
#include "xapian/database.h"

class EstimateOp;

class ValueRangePostList : public PostList {
  protected:
    const Xapian::Database::Internal *db;

    Xapian::valueno slot;

    const std::string begin, end;

    /// Number of times the range test accepted the candidate document.
    Xapian::doccount accepted = 0;

    /// Number of times the range test rejected the candidate document.
    Xapian::doccount rejected = 0;

    /// Object to report accepted/rejected counts to.
    EstimateOp* estimate_op;

    ValueList* valuelist = nullptr;

    /// Disallow copying.
    ValueRangePostList(const ValueRangePostList &);

    /// Disallow assignment.
    void operator=(const ValueRangePostList &);

  public:
    ValueRangePostList(const Xapian::Database::Internal *db_,
                       EstimateOp* estimate_op_,
                       Xapian::doccount termfreq_,
                       Xapian::valueno slot_,
                       const std::string &begin_, const std::string &end_)
        : db(db_), slot(slot_), begin(begin_), end(end_),
          estimate_op(estimate_op_)
    {
        // Static estimate of termfreq based on the slot bounds and range ends.
        termfreq = termfreq_;
    }

    ~ValueRangePostList();

    Xapian::docid get_docid() const;

    double get_weight(Xapian::termcount doclen,
                      Xapian::termcount unique_terms,
                      Xapian::termcount wdfdocmax) const;

    Xapian::termcount get_wdfdocmax() const;

    double recalc_maxweight();

    PositionList * read_position_list();

    PostList * next(double w_min);

    PostList * skip_to(Xapian::docid, double w_min);

    PostList * check(Xapian::docid did, double w_min, bool &valid);

    bool at_end() const;

    Xapian::termcount count_matching_subqs() const;

    std::string get_description() const;
};

#endif /* XAPIAN_INCLUDED_VALUERANGEPOSTLIST_H */
