/*
    * Copyright (C) 2019, Google LLC. and others
    *
    * This program and the accompanying materials are made available under the
    * terms of the Eclipse Distribution License v. 1.0 which is available at
    * https://www.eclipse.org/org/documents/edl-v10.php.
    *
    * SPDX-License-Identifier: BSD-3-Clause
    */
  package org.eclipse.jgit.transport;
  
  import java.util.Collections;
  import java.util.List;
  import java.util.stream.Collectors;
  
  /**
   * {@link org.eclipse.jgit.transport.ProtocolV2Hook} that delegates to a list of
   * other hooks.
   * <p>
   * Hooks are run in the order passed to the constructor. If running a method on
   * one hook throws an exception, execution of remaining hook methods is aborted.
   *
   * @since 5.5
   */
  public class ProtocolV2HookChain implements ProtocolV2Hook {
  	private final List<? extends ProtocolV2Hook> hooks;
  
  	/**
  	 * Create a new hook chaining the given hooks together.
  	 *
  	 * @param hooks
  	 *            hooks to execute, in order.
  	 * @return a new hook chain of the given hooks.
  	 */
  	public static ProtocolV2Hook newChain(
  			List<? extends ProtocolV2Hook> hooks) {
  		List<? extends ProtocolV2Hook> newHooks = hooks.stream()
  				.filter(hook -> !hook.equals(ProtocolV2Hook.DEFAULT))
  				.collect(Collectors.toList());
  
  		if (newHooks.isEmpty()) {
  			return ProtocolV2Hook.DEFAULT;
  		} else if (newHooks.size() == 1) {
  			return newHooks.get(0);
  		} else {
  			return new ProtocolV2HookChain(newHooks);
  		}
  	}
  
  	@Override
  	public void onCapabilities(CapabilitiesV2Request req)
  			throws ServiceMayNotContinueException {
  		for (ProtocolV2Hook hook : hooks) {
  			hook.onCapabilities(req);
  		}
  	}
  
  	@Override
  	public void onLsRefs(LsRefsV2Request req)
  			throws ServiceMayNotContinueException {
  		for (ProtocolV2Hook hook : hooks) {
  			hook.onLsRefs(req);
  		}
  	}
  
  	@Override
  	public void onFetch(FetchV2Request req)
  			throws ServiceMayNotContinueException {
  		for (ProtocolV2Hook hook : hooks) {
  			hook.onFetch(req);
  		}
  	}
  
  	@Override
  	public void onObjectInfo(ObjectInfoRequest req)
  			throws ServiceMayNotContinueException {
  		for (ProtocolV2Hook hook : hooks) {
  			hook.onObjectInfo(req);
  		}
  	}
  
  	private ProtocolV2HookChain(List<? extends ProtocolV2Hook> hooks) {
  		this.hooks = Collections.unmodifiableList(hooks);
  	}
  }