package sk.stuba.fiit.perconik.core.services.resources;

import java.util.Set;

import javax.annotation.Nullable;

import sk.stuba.fiit.perconik.core.Listener;
import sk.stuba.fiit.perconik.core.Resource;
import sk.stuba.fiit.perconik.core.services.AbstractProvider;

import static com.google.common.base.Throwables.propagate;

import static sk.stuba.fiit.perconik.utilities.MoreThrowables.initializeSuppressor;

/**
 * An abstract implementation of {@link ResourceProvider}.
 *
 * TODO doc providing process, class loading / instantiation
 *
 * @author Pavol Zbell
 * @since 1.0
 */
public abstract class AbstractResourceProvider extends AbstractProvider implements ResourceProvider {
  // TODO add javadocs

  /**
   * Constructor for use by subclasses.
   */
  protected AbstractResourceProvider() {}

  protected final ResourceProvider parentOrFailure() {
    ResourceProvider parent = this.parent();

    if (parent == null) {
      throw new IllegalStateException("Provider hierarchy root reached");
    }

    return parent;
  }

  protected final Resource<?> parentForName(final String name, @Nullable final Exception cause) {
    try {
      return this.parentOrFailure().forName(name);
    } catch (Exception failure) {
      throw propagate(initializeSuppressor(failure, cause));
    }
  }

  protected final <L extends Listener> Set<Resource<L>> parentForType(final Class<L> type, @Nullable final Exception cause) {
    try {
      return this.parentOrFailure().forType(type);
    } catch (Exception failure) {
      throw propagate(initializeSuppressor(failure, cause));
    }
  }
}