package com.juick.service;

import com.juick.Tag;
import com.juick.server.helpers.TagStats;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.support.GeneratedKeyHolder;
import org.springframework.jdbc.support.KeyHolder;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.Assert;

import javax.inject.Inject;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

/**
 * Created by aalexeev on 11/13/16.
 */
@Repository
public class TagServiceImpl extends BaseJdbcService implements TagService {
    private static final Pattern TAGS_PATTERN1 = Pattern.compile("^(?:(?:\\*[^ \\r\\n\\t]+)|\\s)+$");
    private static final Pattern TAGS_PATTERN2 = Pattern.compile("^\\*([^ \\r\\n\\t]+)\\s+([\\s\\S]+)");
    private static final Pattern TAG_PATTERN = Pattern.compile("\\*([^ \\r\\n\\t]+)");

    private final MessagesService messagesService;

    @Inject
    public TagServiceImpl(JdbcTemplate jdbcTemplate, MessagesService messagesService) {
        super(jdbcTemplate, null);
        Assert.notNull(messagesService, "MessagesService must be initialized");
        this.messagesService = messagesService;
    }

    @Transactional(readOnly = true)
    @Override
    public com.juick.Tag getTag(final int tid) {
        List<Tag> list = getJdbcTemplate().query(
                "SELECT synonym_id,name FROM tags WHERE tag_id=?",
                (rs, num) -> {
                    Tag ret = new Tag(rs.getString(2));
                    ret.TID = tid;
                    ret.SynonymID = rs.getInt(1);
                    return ret;
                },
                tid);

        return list.isEmpty() ?
                null : list.get(0);
    }

    @Transactional
    @Override
    public com.juick.Tag getTag(final String tag, final boolean autoCreate) {
        if (StringUtils.isBlank(tag))
            return null;

        List<Tag> list = getJdbcTemplate().query(
                "SELECT tag_id, synonym_id, name FROM tags WHERE name = ?",
                (rs, rowNum) -> {
                    Tag ret1 = new Tag(rs.getString(3));
                    ret1.TID = rs.getInt(1);
                    ret1.SynonymID = rs.getInt(2);
                    return ret1;
                },
                tag);

        Tag ret = list.isEmpty() ?
                null : list.get(0);

        if (ret == null && autoCreate) {
            ret = new com.juick.Tag(tag);
            ret.TID = createTag(tag);
        }

        return ret;
    }

    @Override
    public List<Tag> getTags(final String[] tags, final boolean autoCreate) {
        if (ArrayUtils.isEmpty(tags))
            return Collections.emptyList();

        List<Tag> ret = new ArrayList<>();

        for (String tag : tags) {
            if (!tag.isEmpty()) {
                Tag t = getTag(tag, autoCreate);

                if (t != null)
                    ret.add(t);
            }
        }

        return ret.stream().distinct().collect(Collectors.toList());
    }

    @Transactional(readOnly = true)
    @Override
    public boolean getTagNoIndex(final int tagId) {
        List<Integer> list = getJdbcTemplate().queryForList(
                "SELECT noindex FROM tags WHERE tag_id=?", Integer.class, tagId);

        return !list.isEmpty() && list.get(0) == 1;
    }

    @Transactional
    @Override
    public int createTag(final String name) {
        KeyHolder holder = new GeneratedKeyHolder();
        getJdbcTemplate().update(
                con -> {
                    PreparedStatement stmt = con.prepareStatement(
                            "INSERT INTO tags(name) VALUES (?)",
                            Statement.RETURN_GENERATED_KEYS);
                    stmt.setString(1, name);
                    return stmt;
                },
                holder);

        return holder.getKey().intValue();
    }

    private class TagStatsMapper implements RowMapper<TagStats> {

        @Override
        public TagStats mapRow(ResultSet rs, int rowNum) throws SQLException {
            Tag t = new Tag(rs.getString(1));
            TagStats s = new TagStats();
            s.setTag(t);
            s.setUsageCount(rs.getInt(2));
            return s;
        }
    }

    @Transactional(readOnly = true)
    @Override
    public List<TagStats> getUserTagStats(final int uid) {
        return getJdbcTemplate().query(
                "SELECT tags.name,COUNT(messages.message_id) " +
                        "FROM (messages INNER JOIN messages_tags ON (messages.user_id=? " +
                        "AND messages.message_id=messages_tags.message_id)) " +
                        "INNER JOIN tags ON messages_tags.tag_id=tags.tag_id GROUP BY tags.tag_id ORDER BY tags.name ASC",
                new TagStatsMapper(),
                uid);
    }

    @Transactional(readOnly = true)
    @Override
    public List<String> getUserBLTags(final int uid) {
        return getJdbcTemplate().queryForList(
                "SELECT tags.name FROM tags INNER JOIN bl_tags " +
                        "ON (bl_tags.user_id = ? AND bl_tags.tag_id = tags.tag_id) ORDER BY tags.name",
                String.class, uid);
    }

    @Transactional(readOnly = true)
    @Override
    public List<String> getPopularTags() {
        return getJdbcTemplate().queryForList(
                "SELECT name FROM tags WHERE top=1 ORDER BY name ASC", String.class)
                .stream()
                .collect(Collectors.toList());
    }

    @Transactional(readOnly = true)
    @Override
    public List<TagStats> getTagStats() {
        return getJdbcTemplate().query(
                "SELECT tags.name,COUNT(DISTINCT messages.user_id) AS cnt " +
                        "FROM (messages INNER JOIN messages_tags ON (messages.ts>TIMESTAMPADD(DAY,-3,NOW()) " +
                        "AND messages.message_id=messages_tags.message_id)) " +
                        "INNER JOIN tags ON messages_tags.tag_id=tags.tag_id " +
                        "WHERE tags.tag_id NOT IN (SELECT tag_id FROM tags_ignore) " +
                        "GROUP BY tags.tag_id ORDER BY cnt DESC LIMIT 20", new TagStatsMapper());
    }

    @Transactional
    @Override
    public List<Tag> updateTags(final int mid, final Collection<Tag> newTags) {
        List<Tag> currentTags = getMessageTags(mid).stream()
                .map(TagStats::getTag).collect(Collectors.toList());

        if (CollectionUtils.isEmpty(newTags))
            return currentTags;

        List<Integer> idsForDelete = newTags.stream()
                .filter(currentTags::contains)
                .map(tag -> tag.TID)
                .collect(Collectors.toList());

        if (!idsForDelete.isEmpty())
            getNamedParameterJdbcTemplate().update(
                    "DELETE FROM messages_tags WHERE message_id = :mid AND tag_id in (:ids)",
                    new MapSqlParameterSource().addValue("ids", idsForDelete).addValue("mid", mid));

        newTags.stream().filter(t -> !currentTags.contains(t))
                .forEach(t -> getJdbcTemplate().update("INSERT INTO messages_tags(message_id,tag_id) VALUES (?,?)", mid, t.TID));

        return getMessageTags(mid).stream()
                .map(TagStats::getTag).collect(Collectors.toList());
    }

    @Override
    public List<Tag> fromString(final String txt, final boolean tagsOnly) {
        Pattern tagsPattern = tagsOnly ? TAGS_PATTERN1 : TAGS_PATTERN2;

        if (tagsPattern.matcher(txt).matches()) {
            Matcher tagMatcher = TAG_PATTERN.matcher(txt);

            List<Tag> tags = new ArrayList<>();

            // TODO: process readonly, private, friends, public
            while (tagMatcher.find()) {
                for (int i = 1; i <= tagMatcher.groupCount(); i++)
                    tags.add(getTag(tagMatcher.group(i), true));
            }
            return tags;
        }
        return Collections.emptyList();
    }

    @Transactional(readOnly = true)
    @Override
    public List<TagStats> getMessageTags(final int mid) {
        return getJdbcTemplate().query(
                "SELECT tags.tag_id,synonym_id,name,stat_messages FROM tags " +
                        "INNER JOIN messages_tags ON (messages_tags.message_id = ? AND messages_tags.tag_id = tags.tag_id)",
                (rs, num) -> {
                    com.juick.Tag t = new com.juick.Tag(rs.getString(3));
                    t.TID = rs.getInt(1);
                    t.SynonymID = rs.getInt(2);
                    TagStats s = new TagStats();
                    s.setTag(t);
                    s.setUsageCount(rs.getInt(4));
                    return s;
                }, mid);
    }

    @Transactional(readOnly = true)
    @Override
    public List<Integer> getMessageTagsIDs(final int mid) {
        return getJdbcTemplate().queryForList(
                "SELECT tag_id FROM messages_tags WHERE message_id = ?",
                Integer.class, mid);
    }
}