/*
 * 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.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 PostgreGINService 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 String sortHint(String escapedSearchString) {
        boolean isOneWord = escapedSearchString.split("[^\\S\\+]+").length == 1;
        return isOneWord ? " message_id desc" : String.format(" ts_rank(to_tsvector('russian', txt), plainto_tsquery('russian', '%s')) DESC, message_id desc", escapedSearchString);
    }

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

        String usersFilter = userService.getUserBLUsers(visitor.getUid()).stream().map(u -> String.valueOf(u.getUid())).collect(Collectors.joining(","));
        var filter = usersFilter.isBlank() ?
                "to_tsvector('russian', txt) @@ plainto_tsquery('russian', '" + escapeQuery(searchString) + "')"
                : "to_tsvector('russian', txt) @@ plainto_tsquery('russian', '" + escapeQuery(searchString) + "') AND messages.user_id not in (" + usersFilter + ")";
        var offset = page * maxResult;
        var sql = String.format("""
                SELECT messages.message_id FROM messages_txt inner join messages
                on messages.message_id = messages_txt.message_id
                WHERE %s
                ORDER BY %s
                LIMIT %d OFFSET %d
                """, filter, sortHint(escapeQuery(searchString)), maxResult, offset);
        return getJdbcTemplate().queryForList(sql, Integer.class);
    }

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

        var offset = page * maxResult;
        var sql = String.format("""
                SELECT messages.message_id FROM messages_txt inner join messages
                on messages.message_id = messages_txt.message_id
                WHERE to_tsvector('russian', txt) @@ plainto_tsquery('russian', '%s') AND user_id=%d
                ORDER BY %s
                LIMIT %d OFFSET %d
                """, escapeQuery(searchString), userId, sortHint(escapeQuery(searchString)), maxResult, offset);
        return getJdbcTemplate().queryForList(sql, Integer.class);
    }

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

        this.maxResult = maxResult;
    }
}