/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.wicket.request.http;

import java.nio.charset.Charset;
import java.time.Instant;
import java.util.List;
import java.util.Locale;
import javax.servlet.http.Cookie;
import org.apache.wicket.request.IRequestParameters;
import org.apache.wicket.request.Request;
import org.apache.wicket.request.Url;
import org.apache.wicket.util.string.StringValueConversionException;
import org.apache.wicket.util.string.Strings;

/**
 * Base class for request that provides additional web-related information.
 * 
 * @author Matej Knopp
 * @author Igor Vaynberg
 */
public abstract class WebRequest extends Request
{
        /** marker for Ajax requests */
        public static final String PARAM_AJAX = "wicket-ajax";
        /** marker for Ajax requests */
        public static final String HEADER_AJAX = "Wicket-Ajax";
        /** marker for Ajax-relative url */
        public static final String PARAM_AJAX_BASE_URL = "wicket-ajax-baseurl";
        /** marker for Ajax-relative url */
        public static final String HEADER_AJAX_BASE_URL = "Wicket-Ajax-BaseURL";
        /** anti-cache query parameter added by Wicket.Ajax.Request at its URL */
        public static final String PARAM_AJAX_REQUEST_ANTI_CACHE = "_";
        /** {@code Origin} http header */
        public static final String HEADER_ORIGIN = "Origin";
        /** {@code Referer} http header */
        public static final String HEADER_REFERER = "Referer";

        private Boolean isAjax;

        /**
         * @return request cookies
         */
        public abstract List<Cookie> getCookies();

        /**
         * @param cookieName
         * @return cookie with specified name or <code>null</code> if the cookie does not exist
         */
        public Cookie getCookie(final String cookieName)
        {
                for (Cookie cookie : getCookies())
                {
                        if (cookie.getName().equals(cookieName))
                        {
                                return cookie;
                        }
                }
                return null;
        }

        /**
         * Returns all the values of the specified request header.
         * 
         * @param name
         * @return unmodifiable list of header values
         */
        public abstract List<String> getHeaders(String name);

        /**
         * Returns the value of the specified request header as a <code>String</code>
         * 
         * @param name
         * @return string value of request header
         */
        public abstract String getHeader(String name);

        /**
         * Returns the value of the specified request header as a <code>long</code> value that
         * represents a <code>Date</code> object. Use this method with headers that contain dates, such
         * as <code>If-Modified-Since</code>.
         * 
         * @param name
         * @return date value of request header or <code>null</code> if not found
         */
        public abstract Instant getDateHeader(String name);

        /**
         * Convenience method for retrieving If-Modified-Since header.
         * 
         * @return date representing the header or <code>null</code> if not set
         */
        public final Instant getIfModifiedSinceHeader()
        {
                return getDateHeader("If-Modified-Since");
        }


        /**
         * Returns whether this request is an Ajax request. This implementation checks for values of
         * {@value #PARAM_AJAX} url parameter or the {@value #HEADER_AJAX} header. Subclasses can use
         * other approaches.
         * 
         * @return <code>true</code> if this request is an ajax request, <code>false</code> otherwise.
         */
        public boolean isAjax()
        {
                if (isAjax == null)
                {
                        try {
                                isAjax = Strings.isTrue(getHeader(HEADER_AJAX)) ||
                                                Strings.isTrue(getQueryParameters().getParameterValue(PARAM_AJAX).toString());
                        } catch (StringValueConversionException invalidValue) {
                                isAjax = false;
                        }
                }
                return isAjax;
        }

        /**
         * Signals whether or not request processing should preserve the current client url - in other
         * words, handle this request without redirecting. By default, this method returns {@code false}
         * .
         * 
         * For example, this method can be used to preserve the url that caused a 404 in the browser if
         * Wicket is also responsible for rendering the 404 page. If this method returns the default
         * value of {@code false} then Wicket will redirect to the bookmarkable url of the error page,
         * instead of preserving the url that caused the 404 in the browser.
         * 
         * @return {@code true} if current client url should be preserved
         */
        public boolean shouldPreserveClientUrl()
        {
                return false;
        }

        /**
         * Returns request with specified URL and same POST parameters as this request.
         * 
         * @param url
         *            Url instance
         * @return request with specified URL.
         */
        @Override
        public WebRequest cloneWithUrl(final Url url)
        {
                return new WebRequest()
                {
                        @Override
                        public Url getUrl()
                        {
                                return url;
                        }

                        @Override
                        public Url getOriginalUrl()
                        {
                                return WebRequest.this.getOriginalUrl();
                        }

                        @Override
                        public IRequestParameters getPostParameters()
                        {
                                return WebRequest.this.getPostParameters();
                        }

                        @Override
                        public List<Cookie> getCookies()
                        {
                                return WebRequest.this.getCookies();
                        }

                        @Override
                        public Instant getDateHeader(final String name)
                        {
                                return WebRequest.this.getDateHeader(name);
                        }

                        @Override
                        public Locale getLocale()
                        {
                                return WebRequest.this.getLocale();
                        }

                        @Override
                        public String getHeader(final String name)
                        {
                                return WebRequest.this.getHeader(name);
                        }

                        @Override
                        public List<String> getHeaders(final String name)
                        {
                                return WebRequest.this.getHeaders(name);
                        }

                        @Override
                        public Charset getCharset()
                        {
                                return WebRequest.this.getCharset();
                        }

                        @Override
                        public Url getClientUrl()
                        {
                                return WebRequest.this.getClientUrl();
                        }

                        @Override
                        public Object getContainerRequest()
                        {
                                return WebRequest.this.getContainerRequest();
                        }

                        @Override
                        public boolean shouldPreserveClientUrl()
                        {
                                return WebRequest.this.shouldPreserveClientUrl();
                        }
                };
        }

}