/*

 * Copyright (c) 2015, 2016, 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.

 *

 * 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.

 */

import java.io.Closeable;

import java.io.IOException;

import java.io.InputStream;

import java.io.OutputStream;

import java.net.ServerSocket;

import java.net.Socket;

import java.nio.charset.StandardCharsets;

import java.util.Collections;

import java.util.LinkedList;

import java.util.List;

import java.util.Iterator;

import java.util.concurrent.ArrayBlockingQueue;

import java.util.concurrent.TimeUnit;

import java.util.concurrent.atomic.AtomicInteger;

/**

 * A cut-down Http/1 Server for testing various error situations

 *

 * use interrupt() to halt

 */

public class Server extends Thread implements Closeable {

    ServerSocket ss;

    private final List<Connection> sockets;

    private final List<Connection> removals;

    private final List<Connection> additions;

    AtomicInteger counter = new AtomicInteger(0);

    // waits up to 20 seconds for something to happen

    // dont use this unless certain activity coming.

    public Connection activity() {

        for (int i = 0; i < 80 * 100; i++) {

            doRemovalsAndAdditions();

            for (Connection c : sockets) {

                if (c.poll()) {

                    return c;

                }

            }

            try {

                Thread.sleep(250);

            } catch (InterruptedException e) {

                e.printStackTrace();

            }

        }

        return null;

    }

    private void doRemovalsAndAdditions() {

        if (removals.isEmpty() && additions.isEmpty())

            return;

        Iterator<Connection> i = removals.iterator();

        while (i.hasNext())

            sockets.remove(i.next());

        removals.clear();

        i = additions.iterator();

        while (i.hasNext())

            sockets.add(i.next());

        additions.clear();

    }

    // clears all current connections on Server.

    public void reset() {

        for (Connection c : sockets) {

            c.close();

        }

    }

    /**

     * Reads data into an ArrayBlockingQueue<String> where each String

     * is a line of input, that was terminated by CRLF (not included)

     */

    class Connection extends Thread {

        Connection(Socket s) throws IOException {

            this.socket = s;

            id = counter.incrementAndGet();

            is = s.getInputStream();

            os = s.getOutputStream();

            incoming = new ArrayBlockingQueue<>(100);

            setName("Server-Connection");

            setDaemon(true);

        }

        final Socket socket;

        final int id;

        final InputStream is;

        final OutputStream os;

        final ArrayBlockingQueue<String> incoming;

        final static String CRLF = "\r\n";

        // sentinel indicating connection closed

        final static String CLOSED = "C.L.O.S.E.D";

        volatile boolean closed = false;

        @Override

        public void run() {

            byte[] buf = new byte[256];

            String s = "";

            try {

                while (true) {

                    int n = is.read(buf);

                    if (n == -1) {

                        cleanup();

                        return;

                    }

                    String s0 = new String(buf, 0, n, StandardCharsets.ISO_8859_1);

                    s = s + s0;

                    int i;

                    while ((i=s.indexOf(CRLF)) != -1) {

                        String s1 = s.substring(0, i+2);

                        incoming.put(s1);

                        if (i+2 == s.length()) {

                            s = "";

                            break;

                        }

                        s = s.substring(i+2);

                    }

                }

            } catch (IOException |InterruptedException e1) {

                cleanup();

            } catch (Throwable t) {

                System.out.println("X: " + t);

                cleanup();

            }

        }

        @Override

        public String toString() {

            return "Server.Connection: " + socket.toString();

        }

        public void sendHttpResponse(int code, String body, String... headers)

            throws IOException

        {

            String r1 = "HTTP/1.1 " + Integer.toString(code) + " status" + CRLF;

            for (int i=0; i<headers.length; i+=2) {

                r1 += headers[i] + ": " + headers[i+1] + CRLF;

            }

            int clen = body == null ? 0 : body.length();

            r1 += "Content-Length: " + Integer.toString(clen) + CRLF;

            r1 += CRLF;

            if (body != null) {

                r1 += body;

            }

            send(r1);

        }

        // content-length is 10 bytes too many

        public void sendIncompleteHttpResponseBody(int code) throws IOException {

            String body = "Hello World Helloworld Goodbye World";

            String r1 = "HTTP/1.1 " + Integer.toString(code) + " status" + CRLF;

            int clen = body.length() + 10;

            r1 += "Content-Length: " + Integer.toString(clen) + CRLF;

            r1 += CRLF;

            if (body != null) {

                r1 += body;

            }

            send(r1);

        }

        public void sendIncompleteHttpResponseHeaders(int code)

            throws IOException

        {

            String r1 = "HTTP/1.1 " + Integer.toString(code) + " status" + CRLF;

            send(r1);

        }

        public void send(String r) throws IOException {

            os.write(r.getBytes(StandardCharsets.ISO_8859_1));

        }

        public synchronized void close() {

            cleanup();

            closed = true;

            incoming.clear();

        }

        public String nextInput(long timeout, TimeUnit unit) {

            String result = "";

            while (poll()) {

                try {

                    String s = incoming.poll(timeout, unit);

                    if (s == null && closed) {

                        return CLOSED;

                    } else {

                        result += s;

                    }

                } catch (InterruptedException e) {

                    return null;

                }

            }

            return result;

        }

        public String nextInput() {

            return nextInput(0, TimeUnit.SECONDS);

        }

        public boolean poll() {

            return incoming.peek() != null;

        }

        private void cleanup() {

            try {

                socket.close();

            } catch (IOException e) {}

            removals.add(this);

        }

    }

    Server(int port) throws IOException {

        ss = new ServerSocket(port);

        sockets = Collections.synchronizedList(new LinkedList<>());

        removals = Collections.synchronizedList(new LinkedList<>());

        additions = Collections.synchronizedList(new LinkedList<>());

        setName("Test-Server");

        setDaemon(true);

    }

    Server() throws IOException {

        this(0);

    }

    int port() {

        return ss.getLocalPort();

    }

    public String getURL() {

        return "http://127.0.0.1:" + port() + "/foo/";

    }

    private volatile boolean closed;

    @Override

    public void close() {

        closed = true;

        try {

            ss.close();

        } catch (IOException e) {

            e.printStackTrace();

        }

        for (Connection c : sockets) {

            c.close();

        }

    }

    @Override

    public void run() {

        while (!closed) {

            try {

                Socket s = ss.accept();

                Connection c = new Connection(s);

                c.start();

                additions.add(c);

            } catch (IOException e) {

                if (closed)

                    return;

                e.printStackTrace();

            }

        }

    }

}