package mightypork.utils.files;


import java.io.*;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;

import mightypork.utils.string.validation.StringFilter;


/**
 * Utilities for manipulating zip files
 * 
 * @author MightyPork
 */
public class ZipUtils {
	
	private static final int BUFFER_SIZE = 2048;
	
	
	/**
	 * Extract zip file to target directory
	 * 
	 * @param file zip file
	 * @param outputDir target directory
	 * @param filter string filter (will be used to test entry names (paths))
	 * @return list of entries extracted (paths)
	 * @throws IOException
	 */
	public static List<String> extractZip(File file, File outputDir, StringFilter filter) throws IOException
	{
		try (ZipFile zip = new ZipFile(file)) {
			return extractZip(zip, outputDir, filter);
		}
	}
	
	
	/**
	 * Extract zip file to target directory
	 * 
	 * @param zip open zip file
	 * @param outputDir target directory
	 * @param filter string filter (will be used to test entry names (paths))
	 * @return list of entries extracted (paths)
	 * @throws IOException
	 */
	public static List<String> extractZip(ZipFile zip, File outputDir, StringFilter filter) throws IOException
	{
		final ArrayList<String> files = new ArrayList<>();
		
		outputDir.mkdirs();
		
		final Enumeration<? extends ZipEntry> zipFileEntries = zip.entries();
		
		// process each entry
		while (zipFileEntries.hasMoreElements()) {
			final ZipEntry entry = zipFileEntries.nextElement();
			
			// parse filename and path
			final String entryPath = entry.getName();
			final File destFile = new File(outputDir, entryPath);
			final File destinationParent = destFile.getParentFile();
			
			if (entry.isDirectory() || (filter != null && !filter.accept(entryPath))) continue;
			
			// make sure directories exist
			destinationParent.mkdirs();
			
			if (!entry.isDirectory()) {
				extractZipEntry(zip, entry, destFile);
				files.add(entryPath);
			}
		}
		
		return files;
	}
	
	
	/**
	 * Read zip entries and add their paths to a list
	 * 
	 * @param zipFile open zip file
	 * @return list of entry names
	 * @throws IOException on error
	 */
	public static List<String> listZip(File zipFile) throws IOException
	{
		try (ZipFile zip = new ZipFile(zipFile)) {
			return listZip(zip);
		}
	}
	
	
	/**
	 * Read zip entries and add their paths to a list
	 * 
	 * @param zip open zip file
	 * @return list of entry names
	 * @throws IOException on error
	 */
	public static List<String> listZip(ZipFile zip) throws IOException
	{
		final ArrayList<String> files = new ArrayList<>();
		
		final Enumeration<? extends ZipEntry> zipFileEntries = zip.entries();
		
		// process each entry
		while (zipFileEntries.hasMoreElements()) {
			final ZipEntry entry = zipFileEntries.nextElement();
			
			if (!entry.isDirectory()) {
				files.add(entry.getName());
			}
		}
		
		return files;
	}
	
	
	/**
	 * Extract one zip entry to target file
	 * 
	 * @param zip open zip file
	 * @param entry entry from the zip file
	 * @param destFile destination file ((NOT directory!)
	 * @throws IOException on error
	 */
	public static void extractZipEntry(ZipFile zip, ZipEntry entry, File destFile) throws IOException
	{
		destFile.getParentFile().mkdirs();
		
		try (	InputStream in = zip.getInputStream(entry);
				BufferedInputStream is = new BufferedInputStream(in);
				FileOutputStream fos = new FileOutputStream(destFile);
				BufferedOutputStream dest = new BufferedOutputStream(fos, BUFFER_SIZE)) {
			
			FileUtils.copyStream(is, dest);
		}
	}
	
	
	/**
	 * Load zip entry to String
	 * 
	 * @param zip open zip file
	 * @param entry entry from the zip file
	 * @return loaded string
	 * @throws IOException on error
	 */
	public static String zipEntryToString(ZipFile zip, ZipEntry entry) throws IOException
	{
		BufferedInputStream is = null;
		try {
			is = new BufferedInputStream(zip.getInputStream(entry));
			final String s = FileUtils.streamToString(is);
			return s;
		} finally {
			try {
				if (is != null) is.close();
			} catch (final IOException e) {
				// ignore
			}
		}
	}
	
	
	public static boolean entryExists(File selectedFile, String string)
	{
		try (ZipFile zf = new ZipFile(selectedFile)) {
			return zf.getEntry(string) != null;
		} catch (final Exception e) {
			return false;
		}
		
	}
}