package org.etk.core.rest.impl;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;

import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Variant;
import javax.ws.rs.core.Variant.VariantListBuilder;

public class VariantListBuilderImpl extends VariantListBuilder {

  /**
   * Languages.
   */
  private List<Locale>    languages  = new ArrayList<Locale>();

  /**
   * Encodings.
   */
  private List<String>    encodings  = new ArrayList<String>();

  /**
   * Media Types.
   */
  private List<MediaType> mediatypes = new ArrayList<MediaType>();

  /**
   * List of {@link Variant}.
   */
  private List<Variant>   variants;

  /**
   * {@inheritDoc}
   */
  @Override
  public VariantListBuilder add() {
    if (variants == null)
      variants = new ArrayList<Variant>();

    Iterator<MediaType> mediatypesIterator = mediatypes.iterator();

    // do iteration at least one time, even all list are empty
    do {
      MediaType mediaType = mediatypesIterator.hasNext() ? mediatypesIterator.next() : null;
      Iterator<Locale> languagesIterator = languages.iterator();

      do {
        Locale language = languagesIterator.hasNext() ? languagesIterator.next() : null;
        Iterator<String> encodingsIterator = encodings.iterator();

        do {
          String encoding = encodingsIterator.hasNext() ? encodingsIterator.next() : null;
          variants.add(new Variant(mediaType, language, encoding));
        } while (encodingsIterator.hasNext());

      } while (languagesIterator.hasNext());

    } while (mediatypesIterator.hasNext());

    clearAll();
    return this;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public List<Variant> build() {
    return variants == null ? variants = new ArrayList<Variant>() : variants;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public VariantListBuilder encodings(String... encs) {
    for (String enc : encs)
      encodings.add(enc);

    return this;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public VariantListBuilder languages(Locale... langs) {
    for (Locale lang : langs)
      languages.add(lang);

    return this;
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public VariantListBuilder mediaTypes(MediaType... mediaTypes) {
    for (MediaType mediaType : mediaTypes)
      mediatypes.add(mediaType);

    return this;
  }

  /**
   * Reset builder to default state.
   */
  private void clearAll() {
    mediatypes.clear();
    languages.clear();
    encodings.clear();
  }

}