package hycom.service;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.stream.Collectors;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Service;

/**
 * Serwis do parsowania nazwy tabeli.
 */

@Service
public class TableNameParser {

	private static int maxColumnName = 30;

	private static String tablePrefix = "ORBEON_F_";

	/**
	 * Konwerter nazwy tabeli.
	 * @param appName nazwa Aplikacji formularza
	 * @param formName nazwa Formy formularza
	 * @return skrócona nazwa tabeli
	 */
	public static String convertTableName(String appName, String formName) {
		String appXML = xmlToSQLId(appName);
		String formXML = xmlToSQLId(formName);
		String viewName = tablePrefix + joinParts(Arrays.asList(appXML,formXML), maxColumnName - tablePrefix.length());

		return viewName.toLowerCase();
	}

	private static String joinParts(List<String> parts, int max) {
		return String.join("_", fitParts(parts, max));
	}

	private static String xmlToSQLId(String id){
		String result = id.replaceAll("-", "_")
				.toUpperCase() // to uppercase
				.replaceAll("[^A-Z0-9_]", "");
		result = StringUtils.stripStart(result, "_");
		result = StringUtils.stripEnd(result, "_");
		return result;
	}

	private static List<String> fitParts(List<String> parts, int max){
		int usable = max - parts.size() + 1;
		return shaveParts(parts, usable);
	}

	private static List<String> shaveParts(List<String> parts, int usable){
		List<Integer> partsLength = parts.stream().map(String::length).collect(Collectors.toList());
		int totalLength = parts.stream().mapToInt(String::length).sum();

		if(totalLength <= usable) {
			return parts;
		} else {
			Integer maxPartLength = partsLength.stream().max(Comparator.naturalOrder()).orElseThrow(RuntimeException::new);
			int maxPartIndex = partsLength.indexOf(maxPartLength);
			String newPart = StringUtils.stripEnd(removeLastChar(parts.get(maxPartIndex)), "_");
			List<String> newParts = new ArrayList<>(parts);
			newParts.set(maxPartIndex, newPart);

			return shaveParts(newParts, usable);
		}
	}

	private static String removeLastChar(String str) {
		return str.substring(0, str.length() - 1);
	}
}