/*******************************************************************************
 * Copyright (c) 2000, 2003 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.ui.internal.ide.dialogs;

import java.io.*;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.zip.*;

import org.eclipse.core.resources.IFile;
import org.eclipse.core.runtime.CoreException;

/**
 *	Exports resources to a .zip file
 */
/*package*/ class ZipFileResourceExporter {
	private ZipOutputStream		outputStream;
	private StringBuffer		manifestContents;

	private boolean				generateManifestFile = false;
	private boolean				useCompression = true;

	// constants
	private static final String newline = "\r\n";			//$NON-NLS-1$
	private static final String	manifestMagic = "Manifest-Version: 1.0" + newline + newline;//$NON-NLS-1$
	private static final String	nameLabel = "Name: ";//$NON-NLS-1$
	private static final String	digestsLabel = "Digest-Algorithms: SHA MD5" + newline;//$NON-NLS-1$
	private static final String shaLabel = "SHA-Digest: ";//$NON-NLS-1$
	private static final String md5Label = "MD5-Digest: ";//$NON-NLS-1$
	private static final String	manifestPath = "meta-inf/Manifest.mf";//$NON-NLS-1$
/**
 *	Create an instance of this class.
 *
 *	@param filename java.lang.String
 *	@param compress boolean
 *	@param includeManifestFile boolean
 *	@exception java.io.IOException
 */
public ZipFileResourceExporter(String filename,boolean compress,boolean includeManifestFile) throws IOException {
	outputStream = new ZipOutputStream(new FileOutputStream(filename));
	useCompression = compress;
	generateManifestFile = includeManifestFile;

	if (generateManifestFile)
		manifestContents = new StringBuffer(manifestMagic);
}
/**
 *  Create a new entry in the manifest file being constructed.
 *
 *  @param pathname java.lang.String
 *  @param file org.eclipse.core.resources.IFile
 *  @exception java.io.IOException
 *  @exception org.eclipse.core.runtime.CoreException
 */
protected void appendToManifest(String pathname, IFile file) throws IOException, CoreException {
	StringBuffer manifestEntry = new StringBuffer();
	manifestEntry.append(nameLabel);
	manifestEntry.append(pathname);
	manifestEntry.append(newline);
	manifestEntry.append(digestsLabel);
	manifestEntry.append(shaLabel);
	
	byte[] fileContents = null;

	// we don't have to EnsureLocal because it was already done in #write
	InputStream contentStream = file.getContents(false);
	Reader in = new InputStreamReader(contentStream);
	int chunkSize = contentStream.available();
	StringBuffer buffer = new StringBuffer(chunkSize);
	char[] readBuffer = new char[chunkSize];
	int n = in.read(readBuffer);
	while (n > 0) {
		buffer.append(readBuffer);
		n = in.read(readBuffer);
	}
	contentStream.close();  
	fileContents = buffer.toString().getBytes();
	
	try {
		byte[] hashValue = MessageDigest.getInstance("SHA").digest(fileContents);//$NON-NLS-1$
		manifestEntry.append(InternalBase64Encoder.encode(hashValue));
		manifestEntry.append(newline);
		manifestEntry.append(md5Label);
		hashValue = MessageDigest.getInstance("MD5").digest(fileContents);//$NON-NLS-1$
		manifestEntry.append(InternalBase64Encoder.encode(hashValue));
		manifestEntry.append(newline + newline);
	} catch (NoSuchAlgorithmException e) {
		// should never happen
		return;
	}
	manifestContents.append(manifestEntry.toString());
}
/**
 *	Do all required cleanup now that we're finished with the
 *	currently-open .zip
 *
 *	@exception java.io.IOException
 */
public void finished() throws IOException {
	if (generateManifestFile)
		writeManifestFile();
		
	outputStream.close();
}
/**
 *	Create a new ZipEntry with the passed pathname and contents, and write it
 *	to the current archive
 *
 *	@param pathname java.lang.String
 *	@param contents byte[]
 *	@exception java.io.IOException
 */
protected void write(String pathname, byte[] contents) throws IOException {
	ZipEntry newEntry = new ZipEntry(pathname);

	// if the contents are being compressed then we get the below for free.
	if (!useCompression) {
		newEntry.setMethod(ZipEntry.STORED);
		newEntry.setSize(contents.length);
		CRC32 checksumCalculator = new CRC32();
		checksumCalculator.update(contents);
		newEntry.setCrc(checksumCalculator.getValue());
	}

	outputStream.putNextEntry(newEntry);
	outputStream.write(contents);
	outputStream.closeEntry();
}
/**
 *  Write the passed resource to the current archive
 *
 *  @param resource org.eclipse.core.resources.IFile
 *  @param destinationPath java.lang.String
 *  @exception java.io.IOException
 *  @exception org.eclipse.core.runtime.CoreException
 */
public void write(IFile resource, String destinationPath) throws IOException, CoreException {
	ByteArrayOutputStream output = null;
	InputStream contentStream = null;

	try {
		output = new ByteArrayOutputStream();
		contentStream = resource.getContents(false);
		int chunkSize = contentStream.available();
		byte[] readBuffer = new byte[chunkSize];
		int n = contentStream.read(readBuffer);
		
		while (n > 0) {
			output.write(readBuffer);
			n = contentStream.read(readBuffer);
		}
	} finally {
		if (output != null)
			output.close();
		if (contentStream != null)
			contentStream.close();
	}
	
	write(destinationPath,output.toByteArray());
	if (generateManifestFile)
		appendToManifest(destinationPath, resource);
}
/**
 *	Write the constructed manifest.mf file to the current archive
 *
 *	@exception java.io.IOException
 */
protected void writeManifestFile() throws IOException {
	write(manifestPath,manifestContents.toString().getBytes());
}
}