package uk.ac.vamsas.client.simpleclient;

import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Timer;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarInputStream;
import java.util.jar.JarOutputStream;

/**
 * low level vamsas document management routines
 * analogous to ClientsFile
 * Grew out of io tests on VamsasArchive class in uk.ac.vamsas.test.simpleclient.VamsasArchive
 * This class is not thread safe.
 * @author jimp
 *
 */
public class VamsasFile extends SessionFile {
  /**
   * 
   * Connect to an existing Vamsas document in a given sessionDir
   * or create a new one.
   * 
   * @param sessionDir
   * @throws java.io.IOException
   */
  public VamsasFile(File sessionFile) throws java.io.IOException {
    super(sessionFile);
  }
  /**
   * 
   * @return the VamsasFile
   */
  public File getVamsasFile() {
    return sessionFile;
  }
  /**
   * Expand a previously stored session into the sessionDir
   * @param sessionDir
   * @param storedSession
   
   public VamsasFile(File sessionDir, JarFile storedSession) throws IOException {
    // check if sessionDir is live or not
    if (!sessionDir.exists()) {
      sessionDir.mkdir();
    }
    
    {
      // check its actually a writable directory
    }
    
    File sfile = new File(sessionDir, "vamsas.jar");
    VamsasFile(sfile);
    // if live - try to merge storedSession with sessionDir
    //  - will probably fail through duplicate Vobject references needing to be dereferenced.
    // TODO: think of a way of specifying vorba_id scope for an application's references to allow merging of one vamsasDocument with another.
    
  }
  */
  /**
   * public interface for getting a lock.
   * The lock object is internally referenced 
   * so the lock will persist even after the
   * return value of the method goes out of scope.
   * @return null if lock couldn't be got or a valid Lock object.
   */
  public Lock getLock() {
    if (lockFile())
      return fileLock;
    return null;
  }
  /**
   * 
   * @param extantLock
   * @return null, extantLock or new Lock.
   */
  public Lock getLock(Lock extantLock) {
    if (lockFile(extantLock))
      return fileLock;
    return null;
  }
  /**
   * explicitly unlocks vamsas file.
   * if you have called getLock() you *must* 
   * call this to release the lock.
   */
  public void unLock() {
    this.unlockFile();
  }
  
}