/*

 * Copyright (C) 2020, University of the Basque Country (UPV/EHU)

 *  Contact for licensing options: <licensing-mcpttclient(at)mcopenplatform(dot)com>
 *
 * The original file was part of Open Source IMSDROID
 *  Copyright (C) 2010-2011, Mamadou Diop.
 *  Copyright (C) 2011, Doubango Telecom.
 *
 *
 * Contact: Mamadou Diop <diopmamadou(at)doubango(dot)org>
 *
 * This file is part of Open Source Doubango Framework.
 *
 * This is free software: you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by the Free Software Foundation, either version 3
 * of the License, or (at your option) any later version.
 *
 * This 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
 package org.doubango.ngn.utils;
 
 import java.math.BigInteger;
 import java.security.MessageDigest;
 
 public class NgnStringUtils {
 	private static MessageDigest sMD5Digest;
 	
 	public static String emptyValue(){
 		return "";
 	}
 	
 	public static String nullValue(){
 		return "(null)";
 	}
 	
 	public static boolean isNullOrEmpty(String s){
 		return ((s == null) || ("".equals(s)));
 	}
 	
 	public static boolean startsWith(String s, String prefix, boolean ignoreCase){
 		if(s != null && prefix != null){
 			if(ignoreCase){
 				return s.toLowerCase().startsWith(prefix.toLowerCase());
 			}
 			else{
 				return s.startsWith(prefix);
 			}
 		}
 		return s==null && prefix==null;
 	}
 	
 	public static boolean equals(String s1, String s2, boolean ignoreCase){
 		if(s1 != null && s2 != null){
 			if(ignoreCase){
 				return s1.equalsIgnoreCase(s2);
 			}
 			else{
 				return s1.equals(s2);
 			}
 		}
 		else{
 			return ((s1 == null && s2 == null)? true : false);
 		}
 	}
 	
 	public static String unquote(String s, String quote){
 		if(!NgnStringUtils.isNullOrEmpty(s) && !NgnStringUtils.isNullOrEmpty(quote)){
 			if(s.startsWith(quote) && s.endsWith(quote)){
 				return s.substring(1, s.length()-quote.length());
 			}
 		}
 		return s;
 	}
 	
 	public static String quote(String s, String quote){
 		if(!NgnStringUtils.isNullOrEmpty(s) && !NgnStringUtils.isNullOrEmpty(quote)){
 			return quote.concat(s).concat(quote);
 		}
 		return s;
 	}
 	
 	public static long parseLong(String value, long defaultValue){
 		try{
 			if(NgnStringUtils.isNullOrEmpty(value)){
 				return defaultValue;
 			}
 			return Long.parseLong(value);
 		}
 		catch(NumberFormatException e){
 			e.printStackTrace();
 		}
 		return defaultValue;
 	}
 	
 	public static int parseInt(String value, int defaultValue){
 		try{
 			if(NgnStringUtils.isNullOrEmpty(value)){
 				return defaultValue;
 			}
 			return Integer.parseInt(value);
 		}
 		catch(NumberFormatException e){
 			e.printStackTrace();
 		}
 		return defaultValue;
 	}
 	
 	public static String getMD5(String str){
 		if(str != null){
 			try{
 				final BigInteger bigInt;
 				if(sMD5Digest == null){
 					sMD5Digest = MessageDigest.getInstance("MD5");
 				}
 				synchronized (sMD5Digest) {
 					sMD5Digest.reset();
 					bigInt = new BigInteger(1, sMD5Digest.digest(str.getBytes("UTF-8")));
 				}
 				String hash = bigInt.toString(16);
 				while(hash.length() < 32 ){
 					hash = "0" + hash;
 				}
 				return hash;
 			}
 			catch(Exception e){
 				e.printStackTrace();
 				return null;
 			}
 		}
 
 		return null;
 	}
 	
 	public static byte[] getMD5Digest(String str){
 		if(str != null){
 			try{
 				if(sMD5Digest == null){
 					sMD5Digest = MessageDigest.getInstance("MD5");
 				}
 				synchronized (sMD5Digest) {
 					sMD5Digest.reset();
 					return sMD5Digest.digest(str.getBytes("UTF-8"));
 				}
 			}
 			catch(Exception e){
 				e.printStackTrace();
 				return null;
 			}
 		}
 
 		return null;
 	}
 	
 	public static boolean isValidMD5String(String md5String){
 		if(md5String != null){
 			return md5String.length() == 32;
 		}
 		return false;
 	}
 }