package com.erggroup.mass.ant.taskdefs;

import java.io.*;
import java.util.*;
import java.util.zip.*;
import org.apache.tools.ant.*;
import org.apache.tools.ant.taskdefs.*;
import org.apache.tools.ant.types.*;


/**
 * Custom ANT task - given a code JAR and a source base, build a JAR
 * containing the corresponding source code.
 *
 * @ant.examples Here are examples
 *
 */
public class JarSrc extends Task
{
	/**
	 * The binary source file; the src jar will be constructed with a
	 * corresponding name (-src) and will contain the code counterparts.
	 */
	private String binary;

	/**
	 * The location that the source file will be created in.
	 */
	private String toDir;

	/**
	 * The FileSet indicating which corresponding source files should be
	 * obtained (if they exist) from the source path.
	 */
	private FileSet correspondingFileSet = null;

	/**
	 * The set of directories under which the source code is located in
	 * its' expected location.
	 */
	private ArrayList dirsets = new ArrayList();

	/**
	 * Set the filename of the source file. This file is used as a basis
	 * for emulation, by constructing a src package to match.
	 *
	 * @param value the filename.
	 */
	public void setBinary( String value )
	{
		binary = value;
	}

	/**
	 * Set the 'todir', being the directory location in which the source
	 * file will be constructed.
	 *
	 * @param value the directory.
	 */
	public void setToDir( String value )
	{
		toDir = value;
	}

	/**
	 * Nested element - this tag supports nested 'DirSet' elements.
	 */
	public DirSet createDirSet()
	{
		DirSet dirset = new DirSet();
		dirsets.add( dirset );
		return dirset;
	}

	/**
	 *
	 */
	public void execute() throws BuildException
	{
		if ( dirsets.size() == 0 )
		{
			throw new BuildException("At least one DirSet must be provided");
		}

		for ( Iterator i=dirsets.iterator(); i.hasNext(); )
		{
			DirSet dirset = (DirSet)i.next();
			FileScanner scanner = dirset.getDirectoryScanner( getProject() );
			String[] directories = scanner.getIncludedDirectories();
			File basedir = scanner.getBasedir();
			for ( int j=0; j<directories.length; j++ )
			{
				File srcDirectory = new File( basedir, directories[j] );
				packageSource( srcDirectory );
			}
		}
	}

	/**
	 *
	 */
	private void packageSource( File srcDir ) throws BuildException
	{
		log("Packaging source from '" + srcDir + "'", Project.MSG_VERBOSE );
		FileSet corresponding = null;

		try
		{
			corresponding = getCorrespondingNames();
			corresponding.setDir( srcDir );
		}
		catch (IOException x)
		{
			throw new BuildException( "Could not read binary '" + binary + "'", x);
		}

		File binarySource = new File( srcDir, binary );
		String binaryName = binarySource.getName();
		String destName = binaryName.substring(0, binaryName.lastIndexOf("."));
		destName += "-src.jar";
		File destDir = new File( toDir );
		File destFile = new File( toDir, destName );

		// Check that the corresponding src JAR exists; if not, create one.
		Jar jarTask = new Jar();
		jarTask.setTaskName(this.getTaskName());
		jarTask.setProject( getProject() );
		jarTask.setDestFile( destFile );
		jarTask.setUpdate(true);

		jarTask.addFileset( corresponding );
		jarTask.execute();
	}

	/**
	 * Get the corresponding java source names (as a FileSet), by
	 * using the configured 'binary'.
	 *
	 * @return a FileSet containing a list of the expected source
	 *         files.
	 *
	 * @throws IOException if the binary could not be read.
	 */
	private FileSet getCorrespondingNames() throws IOException
	{
		if ( correspondingFileSet == null )
		{
			FileSet corresponding = new FileSet();
			corresponding.setProject( getProject() );

			ZipFile zf = null;
			try
			{
				log("Loading from source binary '" + binary + "'", Project.MSG_VERBOSE );
				zf = new ZipFile(binary);
				Enumeration l_enum = zf.entries();
				while (l_enum.hasMoreElements())
				{
					ZipEntry ze = (ZipEntry)l_enum.nextElement();
					String entryName = ze.getName();
					if ( entryName.endsWith( ".class" ) )
					{
						String correspondingName = entryName.substring(0, entryName.indexOf(".class") );
						correspondingName += ".java";
						log("Adding '" + correspondingName + "' to FileSet", Project.MSG_VERBOSE );
						corresponding.setIncludes( correspondingName );
					}
				}
			}
			finally
			{
				if (zf != null)
				{
					try
					{
						zf.close();
					}
					catch (IOException e)
					{
					}
				}
			}
			correspondingFileSet = corresponding;
		}
		return correspondingFileSet;
	}
}