package org.onap.portalapp.widget.utils;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Map;
import java.util.Stack;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.onap.portalapp.widget.constant.WidgetConstant;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class UnzipUtil {

	/**
	 * Size of the buffer to read/write data
	 */
	private static final int BUFFER_SIZE = 4096;
	private static final Logger logger = LoggerFactory.getLogger(UnzipUtil.class);

	/**
	 * Extracts a zip file specified by the zipFilePath to a directory specified by
	 * destDirectory (will be created if does not exists)
	 * 
	 * @param zipFilePath
	 *            path
	 * @param destDirectory
	 *            directory
	 * @param widgetName
	 *            name
	 * @return Map of contents
	 * @throws IOException
	 *             On error
	 */
	public Map<String, byte[]> unzip_db(String zipFilePath, String destDirectory, String widgetName)
			throws IOException {

		logger.debug("UnzipUtil.unzip_db: unzip widget file {}", widgetName);
		File destDir = new File(destDirectory);
		if (!destDir.exists())
			destDir.mkdir();
		try(ZipInputStream zipIn = new ZipInputStream(new FileInputStream(zipFilePath)))
		{
			ZipEntry entry = zipIn.getNextEntry();
			Map<String, byte[]> map = new HashMap<>();
	
			String[] requiredKeys = { WidgetConstant.WIDGET_CONTROLLER_LOCATION, WidgetConstant.WIDGET_MARKUP_LOCATION,
					WidgetConstant.WIDGET_STYLE_LOCATION };
			for (String k : requiredKeys)
				map.put(k, null);
	
			// iterates over entries in the zip file
			Stack<File> stack = new Stack<>();
			while (entry != null) {
				String filePath = destDirectory + File.separator + widgetName + File.separator
						+ entry.getName().substring(entry.getName().indexOf("/") + 1);
				final String entryShortName = entry.getName().substring(entry.getName().indexOf("/") + 1);
				logger.debug("UnzipUtil.unzip_db: file path {}, short name {}", filePath, entryShortName);
				if (!entry.isDirectory()) {
					// if the entry is a file, extracts it
					logger.debug("UnzipUtil.unzip_db: unzip and save widget file {}", filePath);
					stack.push(new File(filePath));
					extractFile(zipIn, filePath);
				} else {
					// if the entry is a directory, make the directory
					logger.debug("UnzipUtil.unzip_db: unzip and create widget folder {}", filePath);
					File dir = new File(filePath);
					stack.push(new File(filePath));
					dir.mkdir();
				}
				// Is this one we need?
				if (map.containsKey(entryShortName))
					map.put(entryShortName, Files.readAllBytes(Paths.get(filePath)));
				zipIn.closeEntry();
				entry = zipIn.getNextEntry();
			}
		
			while (!stack.isEmpty())
				stack.pop().delete();
	
			for (String k : requiredKeys)
				if (!map.containsKey(k))
					logger.warn("UnzipUtil.unzip_db: no zip archive entry found for required key {}", k);
			
			return map;
		}
	}

	/**
	 * Extracts a zip entry (file entry)
	 * 
	 * @param zipIn
	 * @param filePath
	 * @throws IOException
	 */
	private void extractFile(ZipInputStream zipIn, String filePath) throws IOException {
		try(BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(filePath))){
			byte[] bytesIn = new byte[BUFFER_SIZE];
			int read = 0;
			while ((read = zipIn.read(bytesIn)) != -1) {
				bos.write(bytesIn, 0, read);
			}
		}
	}
}