/*
 * Copyright (C) 2008-2022, Juick
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 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 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/>.
 */

package com.juick.service;

import com.juick.model.User;
import org.apache.commons.lang3.StringUtils;
import org.postgresql.PGConnection;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import javax.inject.Inject;
import javax.sql.DataSource;
import java.sql.SQLException;
import java.util.Collections;
import java.util.List;
import java.util.stream.Collectors;

/**
 * Created by aalexeev on 11/18/16.
 */

@Repository
@ConditionalOnProperty(name = "spring.sql.init.platform", havingValue = "postgresql")
@Transactional(readOnly = true)
public class PostgresSearchService extends BaseJdbcService implements SearchService {
    private static final int DEFAULT_MAX_RESULT = 20;

    private int maxResult = DEFAULT_MAX_RESULT;

    @Inject
    UserService userService;
    @Inject
    DataSource dataSource;

    private String escapeQuery(String searchString) {
        try (var connection = dataSource.getConnection()) {
            var pg = connection.unwrap(PGConnection.class);
            return pg.escapeLiteral(searchString);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return searchString;
    }


    public List<Integer> search(final int visitorId, final int userId, final String searchString, final int page) {
        var usersFilter = userService.getUserIgnoredUsers(visitorId).stream().map(User::getUid).toList();
        var offset = page * maxResult;
        var query = escapeQuery(searchString);
        var isOneWord = query.split("[^\\S\\+]+").length == 1;
        var sql = """
                SELECT
                                    message_id
                                  FROM
                                    (
                                      select
                                        message_id,  user_id, txt,
                                        to_tsvector('russian', txt) v,
                                        websearch_to_tsquery('russian', :query) q
                                      from messages
                                    ) t
                                  WHERE
                                    v @@ q
                """
                + ( userId > 0 ? "AND user_id = :user_id" : "" ) +
                """
                """
                + (usersFilter.isEmpty() ? "" : " AND user_id NOT IN (:filter)") +
                """
                                  ORDER BY
                """
                + (isOneWord ? "message_id DESC" : "ts_rank_cd(v, q) DESC, message_id DESC");
        return getNamedParameterJdbcTemplate().queryForList(sql,
                new MapSqlParameterSource()
                        .addValue("query", escapeQuery(searchString))
                        .addValue("user_id", userId)
                        .addValue("filter", usersFilter), Integer.class).stream()
                .skip(offset).limit(maxResult).collect(Collectors.toList());
    }

    @Override
    public List<Integer> searchInAllMessages(User visitor, final String searchString, final int page) {
        if (StringUtils.isBlank(searchString))
            return Collections.emptyList();
        return search(visitor.getUid(), -1, searchString, page);
    }

    @Override
    public List<Integer> searchByStringAndUser(User visitor, final String searchString, final int userId, int page) {
        if (StringUtils.isBlank(searchString))
            return Collections.emptyList();
        return search(visitor.getUid(), userId, searchString, page);
    }

    @Override
    public void setMaxResult(int maxResult) {
        if (maxResult <= 0)
            throw new IllegalArgumentException("maxResult value (" + maxResult + ") must be greater then 0");
        this.maxResult = maxResult;
    }
}