package application.parsing;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.util.HashMap;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import application.helpers.wrappers.Occupation;
import application.helpers.wrappers.WrappedException;
import application.helpers.wrappers.WriteSelection;
import application.res.Text;

/**
 * This class coordinates the work with the parser (Reading and Writing).
 * @author Bianca
 *
 */
public class ParsingWrapper
{
	/** The {@link ReadHandler} who will give an overview of the health data given**/
	private ReadHandler read;
	/** factory needed for the parser**/
	private SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
	/** the parser**/
	private SAXParser saxParser;   
	/** The health data file**/
	private File srcFile;

	/**
	 * Constructor tries to get access to the health data file
	 * 
	 * @param file file object of the data
	 * @throws Exception in case there was an error while getting access
	 */
	public ParsingWrapper(File file)  throws Exception
	{
		srcFile=file;
        saxParser = saxParserFactory.newSAXParser();
        read = new ReadHandler();
        saxParser.parse(srcFile, read);
        if(read.getExportDate()==null) //wrong file / error reading
        {
        	throw new Exception();
        }
	}
	
	/**
	 * Gives access to the read data
	 * @return
	 */
	public ReadHandler getRead()
	{
		return read;
	}

	/**
	 * Writes the chosen data to the temp-directory
	 * @param selection The users selection on what data to use	
	 * @param job The given job of the user
	 * @return the created files. Keys are the readable filenames 
	 * @throws WrappedException If there was an error with the writing to files
	 */
	public HashMap<String,File> writeSelectedDataToFiles(WriteSelection selection, Occupation job) throws WrappedException
	{
		try 
	    {    	
	        WriteHandler write = new WriteHandler(selection, job);
	        saxParser.parse(srcFile, write);
	        if(write.getErrorMessages()!=null)
	        {
	        	throw new WrappedException(null, write.getErrorMessages());
	        }
	        return write.getAllFiles();
	    } 
	    catch (Exception e) 
	    {
	    	throw new WrappedException(e, Text.E_WRITE_TO_TEMP_FILES);
	    	
	    }
	}

	/**
	 * Wraps the files from the temp directory into a zip file and places it in the given directory.
	 * @param files The files to wrap up
	 * @param targetDir The directory on where to save them
	 * @return The created zip file or {@code null} if writing / creating didn't work
	 */
	public File writeToZipFile(HashMap<String,File> files, File targetDir)
	{
		File target = new File(targetDir, "Export.zip");
		int c=0;
		//file with the same name could already exist
		while(target.exists())
		{
			c++;
			target = new File(targetDir, "Export("+c+").zip");
		}
		boolean created=false;
		try
		{
			created=target.createNewFile();
		}
		catch(Exception e)
		{
			//file couldn't be created due to exception
		}
		if(!created)
		{ //file couldn't be created, so writing impossible
			return null;
		}
		try(FileOutputStream fos = new FileOutputStream(target);
				ZipOutputStream zipOut = new ZipOutputStream(fos))
		{
	        for (String key : files.keySet()) 
	        {
	        	File srcFile=files.get(key);
	            if(srcFile!=null)
	        	{
		            try(FileInputStream fis = new FileInputStream(srcFile))
		            {
		            	String filename= srcFile.getName();
		            	filename=filename.substring(filename.indexOf("__")+2);
			            ZipEntry zipEntry = new ZipEntry(filename);
			            zipOut.putNextEntry(zipEntry);
			            byte[] bytes = new byte[1024];
			            int length;
			            while((length = fis.read(bytes)) >= 0) 
			            {
			                zipOut.write(bytes, 0, length);
			            }
		            }		        		
	        	}
	        }				
		}
		catch(Exception e)
		{
			//Problem with the  file streams, Nothing a user could change so:
			return null;				
		}
		return target;
	}	
}