/*

 * Copyright (c) 2005, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.net.httpserver;

import java.io.*;

import java.net.*;

import javax.net.ssl.*;

import java.util.*;

import java.lang.System.Logger;

import java.lang.System.Logger.Level;

import java.text.*;

import java.util.stream.Stream;

import com.sun.net.httpserver.*;

class ExchangeImpl {

    Headers reqHdrs, rspHdrs;

    Request req;

    String method;

    boolean writefinished;

    URI uri;

    HttpConnection connection;

    long reqContentLen;

    long rspContentLen;

    /* raw streams which access the socket directly */

    InputStream ris;

    OutputStream ros;

    Thread thread;

    /* close the underlying connection when this exchange finished */

    boolean close;

    boolean closed;

    boolean http10 = false;

    /* for formatting the Date: header */

    private static final String pattern = "EEE, dd MMM yyyy HH:mm:ss zzz";

    private static final TimeZone gmtTZ = TimeZone.getTimeZone("GMT");

    private static final ThreadLocal<DateFormat> dateFormat =

         new ThreadLocal<DateFormat>() {

             @Override protected DateFormat initialValue() {

                 DateFormat df = new SimpleDateFormat(pattern, Locale.US);

                 df.setTimeZone(gmtTZ);

                 return df;

         }

     };

    private static final String HEAD = "HEAD";

    /* streams which take care of the HTTP protocol framing

     * and are passed up to higher layers

     */

    InputStream uis;

    OutputStream uos;

    LeftOverInputStream uis_orig; // uis may have be a user supplied wrapper

    PlaceholderOutputStream uos_orig;

    boolean sentHeaders; /* true after response headers sent */

    Map<String,Object> attributes;

    int rcode = -1;

    HttpPrincipal principal;

    ServerImpl server;

    ExchangeImpl (

        String m, URI u, Request req, long len, HttpConnection connection

    ) throws IOException {

        this.req = req;

        this.reqHdrs = req.headers();

        this.rspHdrs = new Headers();

        this.method = m;

        this.uri = u;

        this.connection = connection;

        this.reqContentLen = len;

        /* ros only used for headers, body written directly to stream */

        this.ros = req.outputStream();

        this.ris = req.inputStream();

        server = getServerImpl();

        server.startExchange();

    }

    public Headers getRequestHeaders () {

        return new UnmodifiableHeaders (reqHdrs);

    }

    public Headers getResponseHeaders () {

        return rspHdrs;

    }

    public URI getRequestURI () {

        return uri;

    }

    public String getRequestMethod (){

        return method;

    }

    public HttpContextImpl getHttpContext (){

        return connection.getHttpContext();

    }

    private boolean isHeadRequest() {

        return HEAD.equals(getRequestMethod());

    }

    public void close () {

        if (closed) {

            return;

        }

        closed = true;

        /* close the underlying connection if,

         * a) the streams not set up yet, no response can be sent, or

         * b) if the wrapper output stream is not set up, or

         * c) if the close of the input/outpu stream fails

         */

        try {

            if (uis_orig == null || uos == null) {

                connection.close();

                return;

            }

            if (!uos_orig.isWrapped()) {

                connection.close();

                return;

            }

            if (!uis_orig.isClosed()) {

                uis_orig.close();

            }

            uos.close();

        } catch (IOException e) {

            connection.close();

        }

    }

    public InputStream getRequestBody () {

        if (uis != null) {

            return uis;

        }

        if (reqContentLen == -1L) {

            uis_orig = new ChunkedInputStream (this, ris);

            uis = uis_orig;

        } else {

            uis_orig = new FixedLengthInputStream (this, ris, reqContentLen);

            uis = uis_orig;

        }

        return uis;

    }

    LeftOverInputStream getOriginalInputStream () {

        return uis_orig;

    }

    public int getResponseCode () {

        return rcode;

    }

    public OutputStream getResponseBody () {

        /* TODO. Change spec to remove restriction below. Filters

         * cannot work with this restriction

         *

         * if (!sentHeaders) {

         *    throw new IllegalStateException ("headers not sent");

         * }

         */

        if (uos == null) {

            uos_orig = new PlaceholderOutputStream (null);

            uos = uos_orig;

        }

        return uos;

    }

    /* returns the place holder stream, which is the stream

     * returned from the 1st call to getResponseBody()

     * The "real" ouputstream is then placed inside this

     */

    PlaceholderOutputStream getPlaceholderResponseBody () {

        getResponseBody();

        return uos_orig;

    }

    public void sendResponseHeaders (int rCode, long contentLen)

    throws IOException

    {

        if (sentHeaders) {

            throw new IOException ("headers already sent");

        }

        this.rcode = rCode;

        String statusLine = "HTTP/1.1 "+rCode+Code.msg(rCode)+"\r\n";

        OutputStream tmpout = new BufferedOutputStream (ros);

        PlaceholderOutputStream o = getPlaceholderResponseBody();

        tmpout.write (bytes(statusLine, 0), 0, statusLine.length());

        boolean noContentToSend = false; // assume there is content

        boolean noContentLengthHeader = false; // must not send Content-length is set

        rspHdrs.set ("Date", dateFormat.get().format (new Date()));

        /* check for response type that is not allowed to send a body */

        if ((rCode>=100 && rCode <200) /* informational */

            ||(rCode == 204)           /* no content */

            ||(rCode == 304))          /* not modified */

        {

            if (contentLen != -1) {

                Logger logger = server.getLogger();

                String msg = "sendResponseHeaders: rCode = "+ rCode

                    + ": forcing contentLen = -1";

                logger.log (Level.WARNING, msg);

            }

            contentLen = -1;

            noContentLengthHeader = (rCode != 304);

        }

        if (isHeadRequest() || rCode == 304) {

            /* HEAD requests or 304 responses should not set a content length by passing it

             * through this API, but should instead manually set the required

             * headers.*/

            if (contentLen >= 0) {

                final Logger logger = server.getLogger();

                String msg =

                    "sendResponseHeaders: being invoked with a content length for a HEAD request";

                logger.log (Level.WARNING, msg);

            }

            noContentToSend = true;

            contentLen = 0;

        } else { /* not a HEAD request or 304 response */

            if (contentLen == 0) {

                if (http10) {

                    o.setWrappedStream (new UndefLengthOutputStream (this, ros));

                    close = true;

                } else {

                    rspHdrs.set ("Transfer-encoding", "chunked");

                    o.setWrappedStream (new ChunkedOutputStream (this, ros));

                }

            } else {

                if (contentLen == -1) {

                    noContentToSend = true;

                    contentLen = 0;

                }

                if (!noContentLengthHeader) {

                    rspHdrs.set("Content-length", Long.toString(contentLen));

                }

                o.setWrappedStream (new FixedLengthOutputStream (this, ros, contentLen));

            }

        }

        // A custom handler can request that the connection be

        // closed after the exchange by supplying Connection: close

        // to the response header. Nothing to do if the exchange is

        // already set up to be closed.

        if (!close) {

            Stream<String> conheader =

                    Optional.ofNullable(rspHdrs.get("Connection"))

                    .map(List::stream).orElse(Stream.empty());

            if (conheader.anyMatch("close"::equalsIgnoreCase)) {

                Logger logger = server.getLogger();

                logger.log (Level.DEBUG, "Connection: close requested by handler");

                close = true;

            }

        }

        write (rspHdrs, tmpout);

        this.rspContentLen = contentLen;

        tmpout.flush() ;

        tmpout = null;

        sentHeaders = true;

        if (noContentToSend) {

            WriteFinishedEvent e = new WriteFinishedEvent (this);

            server.addEvent (e);

            closed = true;

        }

        server.logReply (rCode, req.requestLine(), null);

    }

    void write (Headers map, OutputStream os) throws IOException {

        Set<Map.Entry<String,List<String>>> entries = map.entrySet();

        for (Map.Entry<String,List<String>> entry : entries) {

            String key = entry.getKey();

            byte[] buf;

            List<String> values = entry.getValue();

            for (String val : values) {

                int i = key.length();

                buf = bytes (key, 2);

                buf[i++] = ':';

                buf[i++] = ' ';

                os.write (buf, 0, i);

                buf = bytes (val, 2);

                i = val.length();

                buf[i++] = '\r';

                buf[i++] = '\n';

                os.write (buf, 0, i);

            }

        }

        os.write ('\r');

        os.write ('\n');

    }

    private byte[] rspbuf = new byte [128]; // used by bytes()

    /**

     * convert string to byte[], using rspbuf

     * Make sure that at least "extra" bytes are free at end

     * of rspbuf. Reallocate rspbuf if not big enough.

     * caller must check return value to see if rspbuf moved

     */

    private byte[] bytes (String s, int extra) {

        int slen = s.length();

        if (slen+extra > rspbuf.length) {

            int diff = slen + extra - rspbuf.length;

            rspbuf = new byte [2* (rspbuf.length + diff)];

        }

        char c[] = s.toCharArray();

        for (int i=0; i<c.length; i++) {

            rspbuf[i] = (byte)c[i];

        }

        return rspbuf;

    }

    public InetSocketAddress getRemoteAddress (){

        Socket s = connection.getChannel().socket();

        InetAddress ia = s.getInetAddress();

        int port = s.getPort();

        return new InetSocketAddress (ia, port);

    }

    public InetSocketAddress getLocalAddress (){

        Socket s = connection.getChannel().socket();

        InetAddress ia = s.getLocalAddress();

        int port = s.getLocalPort();

        return new InetSocketAddress (ia, port);

    }

    public String getProtocol (){

        String reqline = req.requestLine();

        int index = reqline.lastIndexOf (' ');

        return reqline.substring (index+1);

    }

    public SSLSession getSSLSession () {

        SSLEngine e = connection.getSSLEngine();

        if (e == null) {

            return null;

        }

        return e.getSession();

    }

    public Object getAttribute (String name) {

        if (name == null) {

            throw new NullPointerException ("null name parameter");

        }

        if (attributes == null) {

            attributes = getHttpContext().getAttributes();

        }

        return attributes.get (name);

    }

    public void setAttribute (String name, Object value) {

        if (name == null) {

            throw new NullPointerException ("null name parameter");

        }

        if (attributes == null) {

            attributes = getHttpContext().getAttributes();

        }

        attributes.put (name, value);

    }

    public void setStreams (InputStream i, OutputStream o) {

        assert uis != null;

        if (i != null) {

            uis = i;

        }

        if (o != null) {

            uos = o;

        }

    }

    /**

     * PP

     */

    HttpConnection getConnection () {

        return connection;

    }

    ServerImpl getServerImpl () {

        return getHttpContext().getServerImpl();

    }

    public HttpPrincipal getPrincipal () {

        return principal;

    }

    void setPrincipal (HttpPrincipal principal) {

        this.principal = principal;

    }

    static ExchangeImpl get (HttpExchange t) {

        if (t instanceof HttpExchangeImpl) {

            return ((HttpExchangeImpl)t).getExchangeImpl();

        } else {

            assert t instanceof HttpsExchangeImpl;

            return ((HttpsExchangeImpl)t).getExchangeImpl();

        }

    }

}

/**

 * An OutputStream which wraps another stream

 * which is supplied either at creation time, or sometime later.

 * If a caller/user tries to write to this stream before

 * the wrapped stream has been provided, then an IOException will

 * be thrown.

 */

class PlaceholderOutputStream extends java.io.OutputStream {

    OutputStream wrapped;

    PlaceholderOutputStream (OutputStream os) {

        wrapped = os;

    }

    void setWrappedStream (OutputStream os) {

        wrapped = os;

    }

    boolean isWrapped () {

        return wrapped != null;

    }

    private void checkWrap () throws IOException {

        if (wrapped == null) {

            throw new IOException ("response headers not sent yet");

        }

    }

    public void write(int b) throws IOException {

        checkWrap();

        wrapped.write (b);

    }

    public void write(byte b[]) throws IOException {

        checkWrap();

        wrapped.write (b);

    }

    public void write(byte b[], int off, int len) throws IOException {

        checkWrap();

        wrapped.write (b, off, len);

    }

    public void flush() throws IOException {

        checkWrap();

        wrapped.flush();

    }

    public void close() throws IOException {

        checkWrap();

        wrapped.close();

    }

}