//
// ========================================================================
// Copyright (c) 1995-2020 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under
// the terms of the Eclipse Public License 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0
//
// This Source Code may also be made available under the following
// Secondary Licenses when the conditions for such availability set
// forth in the Eclipse Public License, v. 2.0 are satisfied:
// the Apache License v2.0 which is available at
// https://www.apache.org/licenses/LICENSE-2.0
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//

package org.eclipse.jetty.server.handler;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.URL;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.eclipse.jetty.http.HttpHeader;
import org.eclipse.jetty.http.HttpMethod;
import org.eclipse.jetty.http.MimeTypes;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.util.IO;
import org.eclipse.jetty.util.StringUtil;
import org.eclipse.jetty.util.URIUtil;
import org.eclipse.jetty.util.resource.Resource;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static java.nio.charset.StandardCharsets.UTF_8;

Default Handler.
This handle will deal with unhandled requests in the server.
For requests for favicon.ico, the Jetty icon is served.
For requests to '/' a 404 with a list of known contexts is served.
For all other requests a normal 404 is served.
/**
 * Default Handler.
 *
 * This handle will deal with unhandled requests in the server.
 * For requests for favicon.ico, the Jetty icon is served.
 * For requests to '/' a 404 with a list of known contexts is served.
 * For all other requests a normal 404 is served.
 */
public class DefaultHandler extends AbstractHandler
{
    private static final Logger LOG = LoggerFactory.getLogger(DefaultHandler.class);

    final long _faviconModified = (System.currentTimeMillis() / 1000) * 1000L;
    final byte[] _favicon;
    boolean _serveIcon = true;
    boolean _showContexts = true;

    public DefaultHandler()
    {
        String faviconRef = "/org/eclipse/jetty/favicon.ico";
        byte[] favbytes = null;
        try
        {
            URL fav = getClass().getResource(faviconRef);
            if (fav != null)
            {
                Resource r = Resource.newResource(fav);
                favbytes = IO.readBytes(r.getInputStream());
            }
        }
        catch (Exception e)
        {
            LOG.warn("Unable to find default favicon: {}", faviconRef, e);
        }
        finally
        {
            _favicon = favbytes;
        }
    }

    @Override
    public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
    {
        if (response.isCommitted() || baseRequest.isHandled())
            return;

        baseRequest.setHandled(true);

        String method = request.getMethod();

        // little cheat for common request
        if (_serveIcon && _favicon != null && HttpMethod.GET.is(method) && target.equals("/favicon.ico"))
        {
            if (request.getDateHeader(HttpHeader.IF_MODIFIED_SINCE.toString()) == _faviconModified)
                response.setStatus(HttpServletResponse.SC_NOT_MODIFIED);
            else
            {
                response.setStatus(HttpServletResponse.SC_OK);
                response.setContentType("image/x-icon");
                response.setContentLength(_favicon.length);
                response.setDateHeader(HttpHeader.LAST_MODIFIED.toString(), _faviconModified);
                response.setHeader(HttpHeader.CACHE_CONTROL.toString(), "max-age=360000,public");
                response.getOutputStream().write(_favicon);
            }
            return;
        }

        if (!_showContexts || !HttpMethod.GET.is(method) || !request.getRequestURI().equals("/"))
        {
            response.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        }

        response.setStatus(HttpServletResponse.SC_NOT_FOUND);
        response.setContentType(MimeTypes.Type.TEXT_HTML_UTF_8.toString());

        try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
             OutputStreamWriter writer = new OutputStreamWriter(outputStream, UTF_8))
        {
            writer.append("<!DOCTYPE html>\n");
            writer.append("<html lang=\"en\">\n<head>\n");
            writer.append("<title>Error 404 - Not Found</title>\n");
            writer.append("<meta charset=\"utf-8\">\n");
            writer.append("<style>body { font-family: sans-serif; } table, td { border: 1px solid #333; } td, th { padding: 5px; } thead, tfoot { background-color: #333; color: #fff; } </style>\n");
            writer.append("</head>\n<body>\n");
            writer.append("<h2>Error 404 - Not Found.</h2>\n");
            writer.append("<p>No context on this server matched or handled this request.</p>\n");
            writer.append("<p>Contexts known to this server are:</p>\n");

            writer.append("<table class=\"contexts\"><thead><tr>");
            writer.append("<th>Context Path</th>");
            writer.append("<th>Display Name</th>");
            writer.append("<th>Status</th>");
            writer.append("<th>LifeCycle</th>");
            writer.append("</tr></thead><tbody>\n");

            Server server = getServer();
            Handler[] handlers = server == null ? null : server.getChildHandlersByClass(ContextHandler.class);

            for (int i = 0; handlers != null && i < handlers.length; i++)
            {
                writer.append("<tr><td>");
                // Context Path
                ContextHandler context = (ContextHandler)handlers[i];

                String contextPath = context.getContextPath();
                String href = URIUtil.encodePath(contextPath);
                if (contextPath.length() > 1 && !contextPath.endsWith("/"))
                {
                    href += '/';
                }

                if (context.isRunning())
                {
                    writer.append("<a href=\"").append(href).append("\">");
                }
                writer.append(StringUtil.replace(contextPath, "%", "&#37;"));
                if (context.isRunning())
                {
                    writer.append("</a>");
                }
                writer.append("</td><td>");
                // Display Name

                if (StringUtil.isNotBlank(context.getDisplayName()))
                {
                    writer.append(StringUtil.sanitizeXmlString(context.getDisplayName()));
                }
                writer.append("&nbsp;</td><td>");
                // Available

                if (context.isAvailable())
                {
                    writer.append("Available");
                }
                else
                {
                    writer.append("<em>Not</em> Available");
                }
                writer.append("</td><td>");
                // State
                writer.append(context.getState());
                writer.append("</td></tr>\n");
            }

            writer.append("</tbody></table><hr/>\n");
            writer.append("<a href=\"https://eclipse.org/jetty\"><img alt=\"icon\" src=\"/favicon.ico\"/></a>&nbsp;");
            writer.append("<a href=\"https://eclipse.org/jetty\">Powered by Eclipse Jetty:// Server</a><hr/>\n");
            writer.append("</body>\n</html>\n");
            writer.flush();
            byte[] content = outputStream.toByteArray();
            response.setContentLength(content.length);
            try (OutputStream out = response.getOutputStream())
            {
                out.write(content);
            }
        }
    }

    
Returns:
Returns true if the handle can server the jetty favicon.ico/**
     * @return Returns true if the handle can server the jetty favicon.ico
     */
    public boolean getServeIcon()
    {
        return _serveIcon;
    }

    
Params:
serveIcon – true if the handle can server the jetty favicon.ico/**
     * @param serveIcon true if the handle can server the jetty favicon.ico
     */
    public void setServeIcon(boolean serveIcon)
    {
        _serveIcon = serveIcon;
    }

    public boolean getShowContexts()
    {
        return _showContexts;
    }

    public void setShowContexts(boolean show)
    {
        _showContexts = show;
    }
}