/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.web.servlet.config.annotation;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

import org.springframework.context.ApplicationContext;
import org.springframework.http.HttpStatus;
import org.springframework.lang.Nullable;
import org.springframework.web.servlet.handler.SimpleUrlHandlerMapping;

Assists with the registration of simple automated controllers pre-configured
with status code and/or a view.
Author:
Rossen Stoyanchev, Keith Donald
Since:
3.1/**
 * Assists with the registration of simple automated controllers pre-configured
 * with status code and/or a view.
 *
 * @author Rossen Stoyanchev
 * @author Keith Donald
 * @since 3.1
 */
public class ViewControllerRegistry {

	@Nullable
	private ApplicationContext applicationContext;

	private final List<ViewControllerRegistration> registrations = new ArrayList<>(4);

	private final List<RedirectViewControllerRegistration> redirectRegistrations = new ArrayList<>(10);

	private int order = 1;


	
Class constructor with ApplicationContext. 
Since:
4.3.12/**
	 * Class constructor with {@link ApplicationContext}.
	 * @since 4.3.12
	 */
	public ViewControllerRegistry(@Nullable ApplicationContext applicationContext) {
		this.applicationContext = applicationContext;
	}


	
Map a view controller to the given URL path (or pattern) in order to render
a response with a pre-configured status code and view.
Patterns like "/admin/**" or "/articles/{articlename:\\w+}" are allowed. See AntPathMatcher for more details on the syntax. /**
	 * Map a view controller to the given URL path (or pattern) in order to render
	 * a response with a pre-configured status code and view.
	 * <p>Patterns like {@code "/admin/**"} or {@code "/articles/{articlename:\\w+}"}
	 * are allowed. See {@link org.springframework.util.AntPathMatcher} for more details on the
	 * syntax.
	 */
	public ViewControllerRegistration addViewController(String urlPath) {
		ViewControllerRegistration registration = new ViewControllerRegistration(urlPath);
		registration.setApplicationContext(this.applicationContext);
		this.registrations.add(registration);
		return registration;
	}

	
Map a view controller to the given URL path (or pattern) in order to redirect
to another URL. By default the redirect URL is expected to be relative to
the current ServletContext, i.e. as relative to the web application root.
Since:
4.1/**
	 * Map a view controller to the given URL path (or pattern) in order to redirect
	 * to another URL. By default the redirect URL is expected to be relative to
	 * the current ServletContext, i.e. as relative to the web application root.
	 * @since 4.1
	 */
	public RedirectViewControllerRegistration addRedirectViewController(String urlPath, String redirectUrl) {
		RedirectViewControllerRegistration registration = new RedirectViewControllerRegistration(urlPath, redirectUrl);
		registration.setApplicationContext(this.applicationContext);
		this.redirectRegistrations.add(registration);
		return registration;
	}

	
Map a simple controller to the given URL path (or pattern) in order to
set the response status to the given code without rendering a body.
Since:
4.1/**
	 * Map a simple controller to the given URL path (or pattern) in order to
	 * set the response status to the given code without rendering a body.
	 * @since 4.1
	 */
	public void addStatusController(String urlPath, HttpStatus statusCode) {
		ViewControllerRegistration registration = new ViewControllerRegistration(urlPath);
		registration.setApplicationContext(this.applicationContext);
		registration.setStatusCode(statusCode);
		registration.getViewController().setStatusOnly(true);
		this.registrations.add(registration);
	}

	
Specify the order to use for the HandlerMapping used to map view controllers relative to other handler mappings configured in Spring MVC. 
By default this is set to 1, i.e. right after annotated controllers,
which are ordered at 0.
/**
	 * Specify the order to use for the {@code HandlerMapping} used to map view
	 * controllers relative to other handler mappings configured in Spring MVC.
	 * <p>By default this is set to 1, i.e. right after annotated controllers,
	 * which are ordered at 0.
	 */
	public void setOrder(int order) {
		this.order = order;
	}


	
Return the HandlerMapping that contains the registered view controller mappings, or null for no registrations. 
Since:
4.3.12/**
	 * Return the {@code HandlerMapping} that contains the registered view
	 * controller mappings, or {@code null} for no registrations.
	 * @since 4.3.12
	 */
	@Nullable
	protected SimpleUrlHandlerMapping buildHandlerMapping() {
		if (this.registrations.isEmpty() && this.redirectRegistrations.isEmpty()) {
			return null;
		}

		Map<String, Object> urlMap = new LinkedHashMap<>();
		for (ViewControllerRegistration registration : this.registrations) {
			urlMap.put(registration.getUrlPath(), registration.getViewController());
		}
		for (RedirectViewControllerRegistration registration : this.redirectRegistrations) {
			urlMap.put(registration.getUrlPath(), registration.getViewController());
		}

		SimpleUrlHandlerMapping handlerMapping = new SimpleUrlHandlerMapping();
		handlerMapping.setUrlMap(urlMap);
		handlerMapping.setOrder(this.order);
		return handlerMapping;
	}

}