package simulator.workload.reader.xmlJob;


import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import org.apache.commons.compress.archivers.tar.TarArchiveEntry;
import org.apache.commons.compress.archivers.tar.TarArchiveInputStream;

import simulator.workload.fileFilters.GrmsJobFileNameFilter;

/**
 * 
 * @author Marcin Krystek
 *
 */
public class TarReader implements WLFileAccess{

	protected TarArchiveInputStream tarStream;
	protected TarArchiveEntry entry;
	
	protected TarReader(){
		
	}
	
	public TarReader(String fileName) throws FileNotFoundException{
		FileInputStream fileStream;
		fileStream = new FileInputStream(fileName);
		this.tarStream = new TarArchiveInputStream(fileStream);
	}
	
	public TarReader(File file) throws FileNotFoundException{
		FileInputStream fileStream;
		fileStream = new FileInputStream(file);
		this.tarStream = new TarArchiveInputStream(fileStream);
	}
	
	/**
	 * 
	 * @return file name which contains content returned by read() method
	 */
	public String getFileName(){
		if(entry == null)
			return null;
		
		return entry.getName();
	}
	
	/**
	 * 
	 * @return content of the next file located in tar archive
	 * @throws IOException 
	 * 
	 */
	public String read() throws IOException{

		this.entry = getNextEntry();
		
		if(this.entry == null)
			return null;

		return readEntry(this.entry);
	}
	
	/**
	 * 
	 */
	public void close(){
		if(this.tarStream != null)
			try {
				this.tarStream.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
	}
	
	/**
	 * 
	 * @return
	 * @throws IOException
	 */
	protected TarArchiveEntry getNextEntry() throws IOException{
		
		TarArchiveEntry entry = null;
		
		while((entry = this.tarStream.getNextTarEntry()) != null){
			if(entry.isDirectory())
				continue;
			
			String name = entry.getName();

			int pos = name.lastIndexOf(File.separatorChar);
			if(pos > 0)
				name = name.substring(pos + 1);

			if(!name.startsWith(GrmsJobFileNameFilter.FILE_NAME_PREFIX))
				continue;

			if(!name.endsWith(".xml"))
				continue;
			
			return entry;
		}
		
		return entry;
	}
	
	/**
	 * 
	 * @param entry
	 * @return
	 * @throws IOException
	 */
	protected String readEntry(TarArchiveEntry entry) throws IOException{
		
		int size = (int) entry.getSize();
		byte buf[] = new byte[size];
		this.tarStream.read(buf, 0, size);

		String value = new String(buf);
		return value;
	}
	
}