* @param userMessage the user's message
     * @param userId the user ID (can be null for anonymous users)
     * @param fields the field filters (e.g., label)
     * @param extraQueries the extra query filters (e.g., filetype, timestamp)
     * @return the chat response including session info and sources
     */
    public ChatResult chat(final String sessionId, final String userMessage, final String userId, final Map<String, String[]> fields,

index.delete.timeout=3m
# Timeout for index health checks.
index.health.timeout=10m
# Timeout for index indices operations.
index.indices.timeout=1m

# filetype

# Mapping of MIME types to filetype labels for indexing.
index.filetype=\
text/html=html\n\
application/msword=word\n\
application/vnd.openxmlformats-officedocument.wordprocessingml.document=word\n\
application/vnd.ms-excel=excel\n\

        // mimetype
        putResultDataBody(dataMap, fessConfig.getIndexFieldMimetype(), mimeType);
        if (fileTypeHelper != null) {
            // filetype
            putResultDataBody(dataMap, fessConfig.getIndexFieldFiletype(), fileTypeHelper.get(mimeType));
        }
        // content_length