package vtk;

import java.util.HashMap;
import java.util.Map.Entry;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * Information object return by the Garbage collector. This allow the user to
 * monitor what kind of vtkObject and how many have been removed and kept during
 * the Garbage collection call.
 *
 * @author sebastien jourdain - sebastien.jourdain@kitware.com
 */
public class vtkReferenceInformation {
  private int numberOfObjectsToFree;
  private int numberOfObjectsStillReferenced;
  private HashMap<String, AtomicInteger> classesKept;
  private HashMap<String, AtomicInteger> classesRemoved;
  private boolean keepTrackOfClassNames;

  public vtkReferenceInformation(int nbToFree, int nbToKeep, int totalSize) {
    this.numberOfObjectsToFree = nbToFree;
    this.numberOfObjectsStillReferenced = nbToKeep;
    this.keepTrackOfClassNames = false;
  }

  public vtkReferenceInformation(boolean keepTrackOfClassNames) {
    this.numberOfObjectsToFree = 0;
    this.numberOfObjectsStillReferenced = 0;
    this.keepTrackOfClassNames = keepTrackOfClassNames;
  }

  public int getTotalNumberOfObjects() {
    return numberOfObjectsStillReferenced + numberOfObjectsToFree;
  }

  public int getNumberOfObjectsToFree() {
    return numberOfObjectsToFree;
  }

  public int getTotalNumberOfObjectsStillReferenced() {
    return numberOfObjectsStillReferenced;
  }

  public void setNumberOfObjectsStillReferenced(int numberOfObjectsStillReferenced) {
    this.numberOfObjectsStillReferenced = numberOfObjectsStillReferenced;
  }

  public void setNumberOfObjectsToFree(int numberOfObjectsToFree) {
    this.numberOfObjectsToFree = numberOfObjectsToFree;
  }

  public void addFreeObject(String className) {
    this.numberOfObjectsToFree++;
    if (keepTrackOfClassNames) {
      if (classesRemoved == null && className != null) {
        classesRemoved = new HashMap<String, AtomicInteger>();
      }
      AtomicInteger counter = classesRemoved.get(className);
      if (counter == null) {
        classesRemoved.put(className, new AtomicInteger(1));
      } else {
        counter.incrementAndGet();
      }
    }
  }

  public void addKeptObject(String className) {
    this.numberOfObjectsStillReferenced++;
    if (keepTrackOfClassNames && className != null) {
      if (classesKept == null) {
        classesKept = new HashMap<String, AtomicInteger>();
      }
      AtomicInteger counter = classesKept.get(className);
      if (counter == null) {
        classesKept.put(className, new AtomicInteger(1));
      } else {
        counter.incrementAndGet();
      }
    }
  }

  public String listKeptReferenceToString() {
    if (classesKept == null) {
      return "";
    }
    final StringBuilder builder = new StringBuilder(500);
    builder.append("List of classes kept in Java layer:\n");
    for (Entry<String, AtomicInteger> entry : classesKept.entrySet()) {
      builder.append(" - ").append(entry.getKey()).append(": ").append(entry.getValue().toString()).append("\n");
    }
    return builder.toString();
  }

  public String listRemovedReferenceToString() {
    if (classesRemoved == null) {
      return "";
    }
    final StringBuilder builder = new StringBuilder(500);
    builder.append("List of classes removed in Java layer:\n");
    for (Entry<String, AtomicInteger> entry : classesRemoved.entrySet()) {
      builder.append(" - ").append(entry.getKey()).append(": ").append(entry.getValue().toString()).append("\n");
    }
    return builder.toString();
  }

  public String toString() {
    final StringBuilder builder = new StringBuilder(50);
    builder.append("VTK Gabage Collection: free(");
    builder.append(this.numberOfObjectsToFree);
    builder.append(") - keep(");
    builder.append(this.numberOfObjectsStillReferenced);
    builder.append(") - total(");
    builder.append(this.getTotalNumberOfObjects());
    builder.append(")");
    return builder.toString();
  }
}