/*

 * Copyright (c) 2015, 2017, 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 javax.net.ServerSocketFactory;

import javax.net.ssl.SSLServerSocket;

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 MockServer extends Thread implements Closeable {

    final ServerSocket ss;

    private final List<Connection> sockets;

    private final List<Connection> removals;

    private final List<Connection> additions;

    AtomicInteger counter = new AtomicInteger(0);

    // if specified (not null), only requests which

    // contain this value in their status line

    // will be taken into account and returned by activity().

    // Other requests will get summarily closed.

    // When specified, this can prevent answering to rogue

    // (external) clients that might be lurking

    // on the test machine instead of answering

    // to the test client.

   final String root;

    // 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()) {

                    if (root != null) {

                        // if a root was specified in MockServer

                        // constructor, rejects (by closing) all

                        // requests whose statusLine does not contain

                        // root.

                        if (!c.statusLine.contains(root)) {

                            System.out.println("Bad statusLine: "

                                    + c.statusLine

                                    + " closing connection");

                            c.close();

                            continue;

                        }

                    }

                    return c;

                }

            }

            try {

                Thread.sleep(250);

            } catch (InterruptedException e) {

                e.printStackTrace();

            }

        }

        return null;

    }

    private void doRemovalsAndAdditions() {

        synchronized (removals) {

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

            while (i.hasNext()) {

                Connection c = i.next();

                System.out.println("socket removed: " + c);

                sockets.remove(c);

            }

            removals.clear();

        }

        synchronized (additions) {

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

            while (i.hasNext()) {

                Connection c = i.next();

                System.out.println("socket added: " + c);

                sockets.add(c);

            }

            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;

        volatile String statusLine;

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

        // sentinel indicating connection closed

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

        volatile boolean closed = false;

        volatile boolean released = 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);

                        System.out.println("Server got: " + s1.substring(0,i));

                        if (statusLine == null) statusLine = s1.substring(0,i);

                        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() {

            if (released) return;

            synchronized(this) {

                if (released) return;

                released = true;

            }

            try {

                socket.close();

            } catch (IOException e) {}

            synchronized (removals) {

                removals.add(this);

            }

        }

    }

    MockServer(int port, ServerSocketFactory factory, String root) throws IOException {

        ss = factory.createServerSocket(port);

        this.root = root; // if specified, any request which don't have this value

                          // in their statusLine will be rejected.

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

        removals = new LinkedList<>();

        additions = new LinkedList<>();

        setName("Test-Server");

        setDaemon(true);

    }

    MockServer(int port, ServerSocketFactory factory) throws IOException {

        this(port, factory, "/foo/");

    }

    MockServer(int port) throws IOException {

        this(port, ServerSocketFactory.getDefault());

    }

    MockServer() throws IOException {

        this(0);

    }

    int port() {

        return ss.getLocalPort();

    }

    public String getURL() {

        if (ss instanceof SSLServerSocket) {

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

        } else {

            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() {

        try {

            while (!closed) {

                try {

                    System.out.println("Server waiting for connection");

                    Socket s = ss.accept();

                    Connection c = new Connection(s);

                    c.start();

                    System.out.println("Server got new connection: " + c);

                    synchronized (additions) {

                        additions.add(c);

                    }

                } catch (IOException e) {

                    if (closed)

                        return;

                    e.printStackTrace(System.out);

                }

            }

        } catch (Throwable t) {

            System.out.println("Unexpected exception in accept loop: " + t);

            t.printStackTrace(System.out);

        } finally {

            if (closed) {

                System.out.println("Server closed: exiting accept loop");

            } else {

                System.out.println("Server not closed: exiting accept loop and closing");

                close();

            }

        }

    }

}