package org.vamsas.client.simpleclient;
import org.vamsas.client.*;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutput;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.util.Vector;

/**
 * @author jim
 * Handler for the clientsFile within a vamsas session.
 */
public class ClientsFile {
  private File filelist;
  /**
   * number of my client in list 
   * (not known at start but used when known to make lock)
   */
  private int syncnum=1;
  
  ClientsFile(File filelist) {
    this.filelist=filelist;
  }
  public ClientHandle[] retrieveClientList() {
    if (filelist!=null) {
      if (filelist.exists()) {
        Lock listlock;
        do {
          listlock  = new Lock(filelist); // TODO: wait around if we can't get the lock.
        } while (!listlock.isLocked());
        try {
          ObjectInputStream is = new ObjectInputStream(new BufferedInputStream(new java.io.FileInputStream(filelist)));
          ClientHandle[] clients;
          clients = (ClientHandle[]) ((Vector) is.readObject()).toArray();
          return clients;
        }
        catch (FileNotFoundException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
      // else return null.
    } else {
      throw new Error("Tried to retrieve a clientList without specifying client list filename");
    }
    return null;
       
  }
  public boolean putClientList(ClientHandle[] clients) {
    if (filelist!=null) {
      if (filelist.exists()) {
        Lock listlock;
        do {
          listlock  = new Lock(filelist); // TODO: wait around if we can't get the lock?  should return and make client wait until write has finished so it can read new client info...
        } while (!listlock.isLocked());
        try {
          File templist=File.createTempFile(filelist.getName(),".temp",filelist);
          ObjectOutputStream os = new ObjectOutputStream(new BufferedOutputStream(new FileOutputStream(templist)));
          os.writeObject(clients);
          os.close();
        }
        catch (FileNotFoundException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        } catch (Exception e) {
          e.printStackTrace();
        }
      }
      // else return null.
    } else {
      throw new Error("Tried to retrieve a clientList without specifying client list filename");
    }
    return false;
  }
}