package org.openslx.satserver.util;

import java.io.Closeable;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import java.util.regex.Pattern;

import org.apache.commons.io.FileUtils;

public class Util
{

	/**
	 * Check if the given string starts with any of the additionally passed strings.
	 * Ugly boilerplate.
	 * 
	 * @param stringToCheck a string we want to check the starting of
	 * @param compareTo list of strings we compare stringToCheck to
	 * @return true if stringToCheck starts with any of the strings in compareTo
	 */
	public static boolean startsWith( String stringToCheck, String... compareTo )
	{
		if ( stringToCheck == null )
			return false;
		for ( String check : compareTo ) {
			if ( stringToCheck.startsWith( check ) )
				return true;
		}
		return false;
	}

	/**
	 * Close all given Closables. Can handle null references.
	 * 
	 * @param streams one or more closables/streams
	 */
	public static void multiClose( Closeable... streams )
	{
		if ( streams == null )
			return;
		for ( Closeable stream : streams ) {
			if ( stream != null ) {
				try {
					stream.close();
				} catch ( IOException e ) {
					// Ignore - nothing meaningful to do
				}
			}
		}
	}

	public static boolean streamCopy( InputStream in, OutputStream out, long bytes )
	{
		byte buffer[] = new byte[ 7900 ];
		while ( bytes > 0 ) {
			try {
				int ret = in.read( buffer, 0, (int) ( bytes > buffer.length ? buffer.length : bytes ) );
				if ( ret == -1 )
					return false;
				bytes -= ret;
				out.write( buffer, 0, ret );
			} catch ( IOException e ) {
				e.printStackTrace();
				return false;
			}
		}
		return true;
	}

	public static String readFileToString( String file ) throws IOException
	{
		return FileUtils.readFileToString( new File( file ), StandardCharsets.UTF_8 );
	}

	public static void writeStringToFile( File file, String string ) throws IOException
	{
		FileUtils.writeStringToFile( file, string, StandardCharsets.UTF_8 );
	}

	private static final String[] DEFAULT_ALLOWED_DIRS =
	{ "/tmp/", "/opt/openslx/configs/" };

	public static boolean isAllowedDir( String dir )
	{
		return startsWith( dir, DEFAULT_ALLOWED_DIRS );
	}
	
	private static Pattern nonSpaceExp = Pattern.compile( "[^\\p{C}\\p{Z}]" );

	/**
	 * Whether given string is null, empty, or only matches space-like
	 * characters.
	 */
	public static boolean isEmpty( String string )
	{
		return string == null || !nonSpaceExp.matcher( string ).find();
	}
	
	/**
	 * Parse the given String as a base10 integer.
	 * If the string does not represent a valid integer, return the given
	 * default value.
	 * 
	 * @param value string representation to parse to an int
	 * @param defaultValue fallback value if given string can't be parsed
	 * @return
	 */
	public static int parseInt( String value, int defaultValue )
	{
		try {
			return Integer.parseInt( value );
		} catch ( Exception e ) {
			return defaultValue;
		}
	}

}