/*
 * Copyright (c) MuleSoft, Inc.  All rights reserved.  http://www.mulesoft.com
 * The software in this package is published under the terms of the CPAL v1.0
 * license, a copy of which has been included with this distribution in the
 * LICENSE.txt file.
 */
package org.mule.runtime.core.api.model.resolvers;

import org.mule.runtime.core.api.Event;
import org.mule.runtime.core.api.MuleEventContext;
import org.mule.runtime.core.api.model.EntryPointResolver;
import org.mule.runtime.core.api.model.EntryPointResolverSet;
import org.mule.runtime.core.api.model.InvocationResult;
import org.mule.runtime.core.util.CollectionUtils;

import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Set;

/**
 * Provides the default implementation of an {@link org.mule.runtime.core.api.model.EntryPointResolverSet} It resolves a method to
 * call on the given service when an event is received. This object maintains a set of Resolvers that will be used in order to
 * resolve an entrypoint on a service object until one is found or until the set is exhausted.
 */
public class DefaultEntryPointResolverSet implements EntryPointResolverSet {

  private final Set<EntryPointResolver> entryPointResolvers = new LinkedHashSet<EntryPointResolver>(4);

  public Object invoke(Object component, MuleEventContext context, Event.Builder eventBuilder) throws Exception {
    Set<String> exceptions = new HashSet<String>();

    for (EntryPointResolver resolver : entryPointResolvers) {
      InvocationResult result = resolver.invoke(component, context, eventBuilder);
      if (result.getState() == InvocationResult.State.SUCCESSFUL) {
        return result.getResult();
      } else {
        if (result.hasError()) {
          exceptions.add(result.getErrorMessage());
        }
      }
    }
    throw new EntryPointNotFoundException(CollectionUtils.toString(exceptions, true));
  }

  /**
   * @return the entry point resolves configured in this resolver set. Note that access to the set is not thread safe. Client code
   *         must take proper precautions to synchronize.
   */
  public Set<EntryPointResolver> getEntryPointResolvers() {
    return entryPointResolvers;
  }

  public void setEntryPointResolvers(Set<EntryPointResolver> entryPointResolvers) {
    synchronized (this.entryPointResolvers) {
      this.entryPointResolvers.clear();
      this.entryPointResolvers.addAll(entryPointResolvers);
    }
  }

  public void addEntryPointResolver(EntryPointResolver resolver) {
    synchronized (entryPointResolvers) {
      this.entryPointResolvers.add(resolver);
    }
  }

  public boolean removeEntryPointResolver(EntryPointResolver resolver) {
    synchronized (entryPointResolvers) {
      return this.entryPointResolvers.remove(resolver);
    }
  }
}