/**
 * 
 */
package uk.ac.vamsas.client.simpleclient;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import uk.ac.vamsas.client.ClientHandle;
import uk.ac.vamsas.client.SessionHandle;
import uk.ac.vamsas.client.UserHandle;
import uk.ac.vamsas.client.Vobject;
import uk.ac.vamsas.client.VorbaId;
import uk.ac.vamsas.client.VorbaIdFactory;
import uk.ac.vamsas.objects.utils.document.VersionEntries;

import java.util.Hashtable;
import java.util.zip.CRC32;
/**
 * Simplest VorbaId constructor
 * @author jimp
 *
 */
public class IdFactory extends VorbaIdFactory {
  static Log log = LogFactory.getLog(IdFactory.class);
  private SessionHandle session=null;
  private ClientHandle client;
  private UserHandle user;
  private CRC32 unique=new CRC32(); // used to attempt a unique but predictable stream for IDs
  private String idstring;
  int sequence=1; // incrementing value for next new ID
  /**
   * 
   */
  public IdFactory() {
    super();
    // TODO Auto-generated constructor stub
  }
  
  /**
   * @param session
   * @param client
   * @param user
   */
  protected IdFactory(SessionHandle session, ClientHandle client, UserHandle user) {
    super();
    this.session = session;
    this.client = client;
    this.user = user;
    unique.reset();
    unique.update(new Object[] { session, client, user}.toString().getBytes());
    // TODO: Ensure format of URNs and use standard composition methods.
    idstring = client.getClientNCname()+"_"+unique.getValue()+".";
    extantids=new Hashtable();
    this.extanthashv=new Hashtable();
  }
  /**
   * Create IdFactory with existing object hashes and id set
   * @param session
   * @param client
   * @param user
   * @param extanthashv hash of existing VorbaIds from a previous read of same document
   */
  protected IdFactory(SessionHandle session, ClientHandle client, UserHandle user, Hashtable extanthashv) {
    this(session, client, user);
    this.extanthashv = extanthashv;
  }
  /**
   * values for keys in this hash can be used to reference the uk.ac.vamsas.client.Vobject instance for the VorbaId string.
   * @return the hash of all VorbaIds
   */
  protected Hashtable getVorbaIdHash() {
    return extantids;
  }
  /**
   * values for keys in this hash are Vobjhash objects created for each Vobj with a VorbaId
   * after this factory has been used to write a vamsas archive.
   * @return the hash of all VorbaIds and their hash values.
   */
  protected Hashtable getVobjhashVals() {
    return extanthashv;
  }
  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#makeVorbaId()
   */
  public VorbaId makeVorbaId(Vobject vobject) {
    if (session==null)
      throw new Error("makeVorbaId called on improperly initialised IdFactory Vobject!");
    if (!vobject.isRegisterable())
      throw new Error("makeVorbaId called on unregisterable object.");
    if (vobject.isRegistered())
      throw new Error("makeVorbaId called on already registered object.");
    String newidstring;
    do {
      if (sequence>0) {
        sequence++;
      } else {
        idstring+="1/";
        sequence=1;
      }
      newidstring=idstring+Integer.toString(sequence);
    } while (extantids.containsKey(newidstring));
    VorbaId id = newId(newidstring); // VorbaId.hash()==newidstring.hash() so we can still recover vobject
    extantids.put(id, vobject); // hash the Vobject by its new Id
    return id;
  }

  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#setSession(uk.ac.vamsas.client.SessionHandle)
   */
  protected void setSession(SessionHandle sessionhandle) {
    if (sessionhandle!=null)
      session=sessionhandle;
    else
      log.warn("setSession(null) called.");
  }

  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#getSessionHandle()
   */
  public SessionHandle getSessionHandle() {
    return session;
  }

  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#setClient(uk.ac.vamsas.client.ClientHandle)
   */
  protected void setClient(ClientHandle appHandle) {
    if (appHandle!=null)
      client = appHandle;
    else
      log.warn("setClient(null) called.");
  }

  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#getClientHandle()
   */
  public ClientHandle getClientHandle() {
    return client;
  }

  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#setUser(uk.ac.vamsas.client.UserHandle)
   */
  protected void setUser(UserHandle userHandle) {
  if (userHandle!=null)
    user = userHandle;
  else
    log.warn("setUser(null) called.");
  }

  /* (non-Javadoc)
   * @see uk.ac.vamsas.client.VorbaIdFactory#getUserHandle()
   */
  public UserHandle getUserHandle() {
    return user;
  }
  /**
   * Convenience method used for default behaviour in testing 
   * and any anonymous internal vamsasDocument unmarshalling
   * @param clientname
   * @return
   */
  protected  static IdFactory getDummyFactory(String clientname) {
    if (clientname==null)
      clientname="uk.ac.vamsas.client.simpleclient.IdFactory";
    return new IdFactory(new SessionHandle("dummy.session"), 
        new ClientHandle(clientname,VersionEntries.latestVersion()), 
        new UserHandle(clientname, "Arnold User's Inc."));
  }
}