/*
 * Copyright 2002-2019 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
 *
 *      https://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.mock.web;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.AsyncContext;
import javax.servlet.AsyncEvent;
import javax.servlet.AsyncListener;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.BeanUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.util.WebUtils;

/**
 * Mock implementation of the {@link AsyncContext} interface.
 *
 * @author Rossen Stoyanchev
 * @since 3.2
 */
public class MockAsyncContext implements AsyncContext {

        private final HttpServletRequest request;

        @Nullable
        private final HttpServletResponse response;

        private final List<AsyncListener> listeners = new ArrayList<>();

        @Nullable
        private String dispatchedPath;

        private long timeout = 10 * 1000L;

        private final List<Runnable> dispatchHandlers = new ArrayList<>();


        public MockAsyncContext(ServletRequest request, @Nullable ServletResponse response) {
                this.request = (HttpServletRequest) request;
                this.response = (HttpServletResponse) response;
        }


        public void addDispatchHandler(Runnable handler) {
                Assert.notNull(handler, "Dispatch handler must not be null");
                synchronized (this) {
                        if (this.dispatchedPath == null) {
                                this.dispatchHandlers.add(handler);
                        }
                        else {
                                handler.run();
                        }
                }
        }

        @Override
        public ServletRequest getRequest() {
                return this.request;
        }

        @Override
        @Nullable
        public ServletResponse getResponse() {
                return this.response;
        }

        @Override
        public boolean hasOriginalRequestAndResponse() {
                return (this.request instanceof MockHttpServletRequest && this.response instanceof MockHttpServletResponse);
        }

        @Override
        public void dispatch() {
                dispatch(this.request.getRequestURI());
        }

        @Override
        public void dispatch(String path) {
                dispatch(null, path);
        }

        @Override
        public void dispatch(@Nullable ServletContext context, String path) {
                synchronized (this) {
                        this.dispatchedPath = path;
                        this.dispatchHandlers.forEach(Runnable::run);
                }
        }

        @Nullable
        public String getDispatchedPath() {
                return this.dispatchedPath;
        }

        @Override
        public void complete() {
                MockHttpServletRequest mockRequest = WebUtils.getNativeRequest(this.request, MockHttpServletRequest.class);
                if (mockRequest != null) {
                        mockRequest.setAsyncStarted(false);
                }
                for (AsyncListener listener : this.listeners) {
                        try {
                                listener.onComplete(new AsyncEvent(this, this.request, this.response));
                        }
                        catch (IOException ex) {
                                throw new IllegalStateException("AsyncListener failure", ex);
                        }
                }
        }

        @Override
        public void start(Runnable runnable) {
                runnable.run();
        }

        @Override
        public void addListener(AsyncListener listener) {
                this.listeners.add(listener);
        }

        @Override
        public void addListener(AsyncListener listener, ServletRequest request, ServletResponse response) {
                this.listeners.add(listener);
        }

        public List<AsyncListener> getListeners() {
                return this.listeners;
        }

        @Override
        public <T extends AsyncListener> T createListener(Class<T> clazz) throws ServletException {
                return BeanUtils.instantiateClass(clazz);
        }

        /**
         * By default this is set to 10000 (10 seconds) even though the Servlet API
         * specifies a default async request timeout of 30 seconds. Keep in mind the
         * timeout could further be impacted by global configuration through the MVC
         * Java config or the XML namespace, as well as be overridden per request on
         * {@link org.springframework.web.context.request.async.DeferredResult DeferredResult}
         * or on
         * {@link org.springframework.web.servlet.mvc.method.annotation.SseEmitter SseEmitter}.
         * @param timeout the timeout value to use.
         * @see AsyncContext#setTimeout(long)
         */
        @Override
        public void setTimeout(long timeout) {
                this.timeout = timeout;
        }

        @Override
        public long getTimeout() {
                return this.timeout;
        }

}