package com.juick.service;

import com.juick.Tag;
import org.apache.commons.lang3.StringEscapeUtils;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
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.Statement;
import java.util.ArrayList;
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);
        this.messagesService = messagesService;
    }

    @Transactional(readOnly = true)
    @Override
    public com.juick.Tag getTag(final int tid) {
        try {
            return getJdbcTemplate().queryForObject(
                    "SELECT synonym_id,name FROM tags WHERE tag_id=?",
                    (rs, num) -> {
                        Tag ret = new Tag(StringEscapeUtils.unescapeHtml4(rs.getString(2)));
                        ret.TID = tid;
                        ret.SynonymID = rs.getInt(1);
                        return ret;
                    },
                    tid);
        } catch (EmptyResultDataAccessException e) {
            return null;
        }
    }

    @Transactional(readOnly = true)
    @Override
    public com.juick.Tag getTag(final String tag, final boolean autoCreate) {
        Tag ret = null;
        try {
            ret = getJdbcTemplate().queryForObject(
                    "SELECT tag_id,synonym_id,name FROM tags WHERE name=?",
                    (rs, rowNum) -> {
                        Tag ret1 = new Tag(StringEscapeUtils.unescapeHtml4(rs.getString(3)));
                        ret1.TID = rs.getInt(1);
                        ret1.SynonymID = rs.getInt(2);
                        return ret1;
                    },
                    StringEscapeUtils.escapeHtml4(tag));
        } catch (EmptyResultDataAccessException e) {
            // tag not found
        }
        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) {
        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;
    }

    @Transactional(readOnly = true)
    @Override
    public boolean getTagNoIndex(final int tag_id) {
        try {
            return getJdbcTemplate().queryForObject(
                    "SELECT noindex FROM tags WHERE tag_id=?", Integer.class, tag_id) == 1;
        } catch (EmptyResultDataAccessException e) {
            return false;
        }
    }

    @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, StringEscapeUtils.escapeHtml4(name));
            return stmt;
        }, holder);

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

    @Transactional(readOnly = true)
    @Override
    public List<com.juick.Tag> getUserTagsAll(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",
                (rs, rowNum) -> {
                    Tag t = new Tag(StringEscapeUtils.unescapeHtml4(rs.getString(1)));
                    t.UsageCnt = rs.getInt(2);
                    return t;
                }, 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()
                .map(StringEscapeUtils::unescapeHtml4).collect(Collectors.toList());
    }

    @Transactional
    @Override
    public List<Tag> updateTags(final int mid, final List<Tag> newTags) {
        List<Tag> currentTags = messagesService.getMessageTags(mid);
        newTags.stream().filter(currentTags::contains)
                .forEach(t -> getJdbcTemplate().update(
                        "DELETE FROM messages_tags WHERE message_id=? AND tag_id=?",
                        mid,
                        t.TID));
        newTags.stream().filter(t -> !currentTags.contains(t))
                .forEach(t -> getJdbcTemplate().update(
                        "INSERT INTO messages_tags(message_id,tag_id) VALUES (?,?)", mid, t.TID));
        return messagesService.getMessageTags(mid);
    }

    @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();
    }
}