remwharead/include/search.hpp

/*  This file is part of remwharead.
 *  Copyright © 2019 tastytea <tastytea@tastytea.de>
 *
 *  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, version 3.
 *
 *  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 <http://www.gnu.org/licenses/>.
 */

#ifndef REMWHAREAD_SEARCH_HPP
#define REMWHAREAD_SEARCH_HPP

#include "sqlite.hpp"
#include <list>
#include <string>
#include <vector>

namespace remwharead
{
using std::list;
using std::string;
using std::vector;

/*!
 *  @brief  %Search in database entries.
 *
 *  @since  0.7.0
 *
 *  @headerfile search.hpp remwharead/search.hpp
 */
class Search
{
public:
    /*!
     *  @brief  Defines the entries to search.
     *
     *  @since  0.7.0
     */
    explicit Search(list<Database::entry> entries);

    /*!
     *  @brief  %Search in tags of database entries.
     *
     *  Only matches whole tags, *Pill* does not match *Pillow*.
     *
     *  @param  expression %Search expression.
     *  @param  is_re      Is it a regular expression?
     *
     *  @return List of matching Database::entry.
     *
     *  @since  0.7.0
     */
    [[nodiscard]]
    list<Database::entry> search_tags(const string &expression, bool is_re)
        const;

    /*!
     *  @brief  %Search in full text of database entries.
     *
     *  Searches in tags, title, description and full text.
     *
     *  @param  expression %Search expression.
     *  @param  is_re      Is it a regular expression?
     *
     *  @return List of matching Database::entry.
     *
     *  @since  0.7.0
     */
    [[nodiscard]]
    list<Database::entry> search_all(const string &expression, bool is_re)
        const;

    /*!
     *  @brief  Spawn threads of search_all(), if it seems sensible.
     *
     *  Figure out if threads could be useful and spawn a sensible amount of
     *  them.
     *
     *  @param  expression %Search expression.
     *  @param  is_re      Is it a regular expression?
     *
     *  @return List of matching Database::entry.
     *
     *  @since  0.7.2
     */
    // TODO(tastytea): Think of something more elegant.
    [[nodiscard]]
    list<Database::entry> search_all_threaded(const string &expression,
                                              bool is_re) const;

private:
    const list<Database::entry> _entries;

    /*!
     *  @brief  Split expression into subexpressions.
     *
     *  First it splits at `OR` or `||`, then it splits the subexpressions
     *  at `AND` or `&&`. The first vector contains all tags before the
     *  first `OR`.
     *
     *  @return Vector of `OR`-vectors of `AND`-tags.
     *
     *  @since  0.7.0
     */
    [[nodiscard]]
    static vector<vector<string>> parse_expression(const string &expression);

    /*!
     *  @brief  Convert str to lowercase. Works with unicode.
     *
     *  @since  0.7.0
     */
    [[nodiscard]]
    static inline string to_lowercase(const string &str);
};
} // namespace remwharead

#endif  // REMWHAREAD_SEARCH_HPP