/*
 *  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
 *
 *    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.apache.grails.web.layout;

import java.io.IOException;

import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpServletResponseWrapper;

import com.opensymphony.module.sitemesh.PageParser;
import com.opensymphony.module.sitemesh.PageParserSelector;
import com.opensymphony.sitemesh.Content;
import com.opensymphony.sitemesh.ContentProcessor;
import com.opensymphony.sitemesh.webapp.SiteMeshWebAppContext;

import grails.web.mvc.GrailsResponseMutator;
import org.grails.buffer.StreamCharBuffer;
import org.grails.web.servlet.mvc.GrailsWebRequest;
import org.grails.web.util.WebUtils;

public class GrailsContentBufferingResponse extends HttpServletResponseWrapper implements GrailsResponseMutator, StreamCharBuffer.LazyInitializingWriter {

    private final GrailsPageResponseWrapper pageResponseWrapper;
    private final ContentProcessor contentProcessor;
    private final SiteMeshWebAppContext webAppContext;
    private boolean redirectCalled;

    public GrailsContentBufferingResponse(HttpServletResponse response, final ContentProcessor contentProcessor, final SiteMeshWebAppContext webAppContext) {
        super(new GrailsPageResponseWrapper(webAppContext.getRequest(), response, new PageParserSelector() {
            public boolean shouldParsePage(String contentType) {
                return contentProcessor.handles(contentType);
            }

            public PageParser getPageParser(String contentType) {
                // Migration: Not actually needed by PageResponseWrapper, so long as getPage() isn't called.
                return null;
            }
        }) {
            @Override
            public void setContentType(String contentType) {
                webAppContext.setContentType(contentType);
                super.setContentType(contentType);
            }
        });
        this.contentProcessor = contentProcessor;
        this.webAppContext = webAppContext;
        pageResponseWrapper = (GrailsPageResponseWrapper) getResponse();
        if (response.getContentType() != null) {
            webAppContext.setContentType(response.getContentType());
        }
    }

    public HttpServletResponse getTargetResponse() {
        return (HttpServletResponse) pageResponseWrapper.getResponse();
    }

    /**
     * Always report this buffering response as committed. This forces Spring's
     * {@link org.springframework.web.servlet.view.InternalResourceView} to use
     * {@code include()} instead of {@code forward()} for JSP views. Tomcat 11
     * (Jakarta Servlet 6.1) calls {@code finish()} on the underlying response
     * after a forward completes, which commits the real response and prevents the
     * layout decorator from writing decorated output. Using include avoids this.
     *
     * This is safe because {@code GrailsContentBufferingResponse} is only used
     * inside {@link EmbeddedGrailsLayoutView#obtainContent} to capture the inner
     * view's output, and is discarded after content capture completes.
     */
    @Override
    public boolean isCommitted() {
        return true;
    }

    public boolean isUsingStream() {
        return pageResponseWrapper.isUsingStream();
    }

    public boolean isActive() {
        return pageResponseWrapper.isGrailsLayoutActive() || pageResponseWrapper.isGspGrailsLayoutActive();
    }

    public void deactivateGrailsLayout() {
        pageResponseWrapper.deactivateGrailsLayout();
    }

    public Content getContent() throws IOException {
        if (!pageResponseWrapper.isGrailsLayoutActive()) {
            return null;
        }

        GSPGrailsLayoutPage content = (GSPGrailsLayoutPage) webAppContext.getRequest().getAttribute(EmbeddedGrailsLayoutView.GSP_GRAILS_LAYOUT_PAGE);
        if (content != null && content.isUsed()) {
            return content;
        }

        char[] data = pageResponseWrapper.getContents();
        if (data != null && webAppContext.getContentType() != null) {
            return contentProcessor.build(data, webAppContext);
        }

        return null;
    }

    @Override
    public void sendError(int sc) throws IOException {
        GrailsWebRequest webRequest = GrailsWebRequest.lookup();

        try {
            if (!redirectCalled && !isCommitted()) {
                super.sendError(sc);
            }
        } finally {
            if (webRequest != null) {
                WebUtils.storeGrailsWebRequest(webRequest);
            }
        }
    }

    @Override
    public void sendError(int sc, String msg) throws IOException {
        GrailsWebRequest webRequest = GrailsWebRequest.lookup();
        try {
            if (!redirectCalled && !isCommitted()) {
                super.sendError(sc, msg);
            }
        } finally {
            if (webRequest != null) {
                WebUtils.storeGrailsWebRequest(webRequest);
            }
        }
    }

    @Override
    public void sendRedirect(String location) throws IOException {
        this.redirectCalled = true;
        super.sendRedirect(location);
    }

    @Override
    public void deactivateResponseMutator() {
        deactivateGrailsLayout();
    }
}
