//
//  ========================================================================
//  Copyright (c) 1995-2017 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.server;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.charset.StandardCharsets;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;

import org.eclipse.jetty.http.HttpField;
import org.eclipse.jetty.http.HttpParser;
import org.eclipse.jetty.http.HttpVersion;
import org.eclipse.jetty.io.ByteArrayEndPoint;
import org.eclipse.jetty.io.ByteBufferPool;
import org.eclipse.jetty.io.Connection;
import org.eclipse.jetty.util.BufferUtil;
import org.eclipse.jetty.util.ByteArrayOutputStream2;
import org.eclipse.jetty.util.ssl.SslContextFactory;
import org.eclipse.jetty.util.thread.Scheduler;

/**
 * A local connector, mostly for testing purposes.
 * <pre>
 *  HttpTester.Request request = HttpTester.newRequest();
 *  request.setURI("/some/resource");
 *  HttpTester.Response response = 
 *      HttpTester.parseResponse(HttpTester.from(localConnector.getResponse(request.generate())));
 * </pre>
 *
 */
public class LocalConnector extends AbstractConnector
{
    private final BlockingQueue<LocalEndPoint> _connects = new LinkedBlockingQueue<>();

    public LocalConnector(Server server, Executor executor, Scheduler scheduler, ByteBufferPool pool, int acceptors, ConnectionFactory... factories)
    {
        super(server,executor,scheduler,pool,acceptors,factories);
        setIdleTimeout(30000);
    }

    public LocalConnector(Server server)
    {
        this(server, null, null, null, -1, new HttpConnectionFactory());
    }

    public LocalConnector(Server server, SslContextFactory sslContextFactory)
    {
        this(server, null, null, null, -1,AbstractConnectionFactory.getFactories(sslContextFactory,new HttpConnectionFactory()));
    }

    public LocalConnector(Server server, ConnectionFactory connectionFactory)
    {
        this(server, null, null, null, -1, connectionFactory);
    }

    public LocalConnector(Server server, ConnectionFactory connectionFactory, SslContextFactory sslContextFactory)
    {
        this(server, null, null, null, -1, AbstractConnectionFactory.getFactories(sslContextFactory,connectionFactory));
    }

    @Override
    public Object getTransport()
    {
        return this;
    }

    /** Sends requests and get responses based on thread activity.
     * Returns all the responses received once the thread activity has
     * returned to the level it was before the requests.
     * <p>
     * This methods waits until the connection is closed or
     * is idle for 5s before returning the responses.
     * <p>Use {@link #getResponse(String)} for an alternative that does not wait for idle.
     * @param requests the requests
     * @return the responses
     * @throws Exception if the requests fail
     */
    public String getResponses(String requests) throws Exception
    {
        return getResponses(requests, 5, TimeUnit.SECONDS);
    }

    /** Sends requests and get responses based on thread activity.
     * Returns all the responses received once the thread activity has
     * returned to the level it was before the requests.
     * <p>
     * This methods waits until the connection is closed or
     * an idle period before returning the responses.
     * <p>Use {@link #getResponse(String)} for an alternative that does not wait for idle.
     * @param requests the requests
     * @param idleFor The time the response stream must be idle for before returning
     * @param units The units of idleFor
     * @return the responses
     * @throws Exception if the requests fail
     */
    public String getResponses(String requests,long idleFor,TimeUnit units) throws Exception
    {
        ByteBuffer result = getResponses(BufferUtil.toBuffer(requests,StandardCharsets.UTF_8),idleFor,units);
        return result==null?null:BufferUtil.toString(result,StandardCharsets.UTF_8);
    }

    /** Sends requests and get's responses based on thread activity.
     * Returns all the responses received once the thread activity has
     * returned to the level it was before the requests.
     * <p>
     * This methods waits until the connection is closed or
     * is idle for 5s before returning the responses.
     * <p>Use {@link #getResponse(ByteBuffer)} for an alternative that does not wait for idle.
     * @param requestsBuffer the requests
     * @return the responses
     * @throws Exception if the requests fail
     */
    public ByteBuffer getResponses(ByteBuffer requestsBuffer) throws Exception
    {
        return getResponses(requestsBuffer, 5, TimeUnit.SECONDS);
    }

    /** Sends requests and get's responses based on thread activity.
     * Returns all the responses received once the thread activity has
     * returned to the level it was before the requests.
     * <p>
     * This methods waits until the connection is closed or
     * an idle period before returning the responses.
     * @param requestsBuffer the requests
     * @param idleFor The time the response stream must be idle for before returning
     * @param units The units of idleFor
     * @return the responses
     * @throws Exception if the requests fail
     */
    public ByteBuffer getResponses(ByteBuffer requestsBuffer,long idleFor,TimeUnit units) throws Exception
    {
        if (LOG.isDebugEnabled())
            LOG.debug("requests {}", BufferUtil.toUTF8String(requestsBuffer));
        LocalEndPoint endp = executeRequest(requestsBuffer);
        endp.waitUntilClosedOrIdleFor(idleFor,units);
        ByteBuffer responses = endp.takeOutput();
        if (endp.isOutputShutdown())
            endp.close();
        if (LOG.isDebugEnabled())
            LOG.debug("responses {}", BufferUtil.toUTF8String(responses));
        return responses;
    }

    /**
     * Execute a request and return the EndPoint through which
     * multiple responses can be received or more input provided.
     * @param rawRequest the request
     * @return the local endpoint
     */
    public LocalEndPoint executeRequest(String rawRequest)
    {
        return executeRequest(BufferUtil.toBuffer(rawRequest, StandardCharsets.UTF_8));
    }

    private LocalEndPoint executeRequest(ByteBuffer rawRequest)
    {
        if (!isStarted())
            throw new IllegalStateException("!STARTED");
        LocalEndPoint endp = new LocalEndPoint();
        endp.addInput(rawRequest);
        _connects.add(endp);
        return endp;
    }

    public LocalEndPoint connect()
    {
        LocalEndPoint endp = new LocalEndPoint();
        _connects.add(endp);
        return endp;
    }
    
    @Override
    protected void accept(int acceptorID) throws IOException, InterruptedException
    {
        if (LOG.isDebugEnabled())
            LOG.debug("accepting {}", acceptorID);
        LocalEndPoint endPoint = _connects.take();
        endPoint.onOpen();
        onEndPointOpened(endPoint);

        Connection connection = getDefaultConnectionFactory().newConnection(this, endPoint);
        endPoint.setConnection(connection);

        connection.onOpen();
    }


    /** Get a single response using a parser to search for the end of the message.
     * @param requestsBuffer The request to send
     * @return ByteBuffer containing response or null.
     * @throws Exception If there is a problem
     */
    public ByteBuffer getResponse(ByteBuffer requestsBuffer) throws Exception
    {
        return getResponse(requestsBuffer,false,10,TimeUnit.SECONDS);
    }

    /** Get a single response using a parser to search for the end of the message.
     * @param requestBuffer The request to send
     * @param time The time to wait
     * @param unit The units of the wait
     * @return ByteBuffer containing response or null.
     * @throws Exception If there is a problem
     */
    public ByteBuffer getResponse(ByteBuffer requestBuffer, long time,TimeUnit unit) throws Exception
    {
        boolean head = BufferUtil.toString(requestBuffer).toLowerCase().startsWith("head ");
        if (LOG.isDebugEnabled())
            LOG.debug("requests {}", BufferUtil.toUTF8String(requestBuffer));
        LocalEndPoint endp = executeRequest(requestBuffer);
        return endp.waitForResponse(head,time,unit);
    }
    
    /** Get a single response using a parser to search for the end of the message.
     * @param requestBuffer The request to send
     * @param head True if the response is for a head request
     * @param time The time to wait
     * @param unit The units of the wait
     * @return ByteBuffer containing response or null.
     * @throws Exception If there is a problem
     */
    public ByteBuffer getResponse(ByteBuffer requestBuffer,boolean head, long time,TimeUnit unit) throws Exception
    {
        if (LOG.isDebugEnabled())
            LOG.debug("requests {}", BufferUtil.toUTF8String(requestBuffer));
        LocalEndPoint endp = executeRequest(requestBuffer);
        return endp.waitForResponse(head,time,unit);
    }

    
    /** Get a single response using a parser to search for the end of the message.
     * @param rawRequest The request to send
     * @return ByteBuffer containing response or null.
     * @throws Exception If there is a problem
     */
    public String getResponse(String rawRequest) throws Exception
    {
        return getResponse(rawRequest,false,30,TimeUnit.SECONDS);
    }

    /** Get a single response using a parser to search for the end of the message.
     * @param rawRequest The request to send
     * @param time The time to wait
     * @param unit The units of the wait
     * @return ByteBuffer containing response or null.
     * @throws Exception If there is a problem
     */
    public String getResponse(String rawRequest,long time,TimeUnit unit) throws Exception
    {
        boolean head = rawRequest.toLowerCase().startsWith("head ");
        ByteBuffer requestsBuffer = BufferUtil.toBuffer(rawRequest, StandardCharsets.ISO_8859_1);
        if (LOG.isDebugEnabled())
            LOG.debug("request {}", BufferUtil.toUTF8String(requestsBuffer));
        LocalEndPoint endp = executeRequest(requestsBuffer);
        
        return BufferUtil.toString(endp.waitForResponse(head,time,unit), StandardCharsets.ISO_8859_1);
    }
    
    
    /** Get a single response using a parser to search for the end of the message.
     * @param rawRequest The request to send
     * @param head True if the response is for a head request
     * @param time The time to wait
     * @param unit The units of the wait
     * @return ByteBuffer containing response or null.
     * @throws Exception If there is a problem
     */
    public String getResponse(String rawRequest, boolean head, long time,TimeUnit unit) throws Exception
    {
        ByteBuffer requestsBuffer = BufferUtil.toBuffer(rawRequest, StandardCharsets.ISO_8859_1);
        if (LOG.isDebugEnabled())
            LOG.debug("request {}", BufferUtil.toUTF8String(requestsBuffer));
        LocalEndPoint endp = executeRequest(requestsBuffer);
        
        return BufferUtil.toString(endp.waitForResponse(head,time,unit), StandardCharsets.ISO_8859_1);
    }
    
    /** Local EndPoint
     */
    public class LocalEndPoint extends ByteArrayEndPoint
    {
        private final CountDownLatch _closed = new CountDownLatch(1);
        private ByteBuffer _responseData;

        public LocalEndPoint()
        {
            super(LocalConnector.this.getScheduler(), LocalConnector.this.getIdleTimeout());
            setGrowOutput(true);
        }
        
        protected void execute(Runnable task)
        {
            getExecutor().execute(task);
        }

        @Override
        public void close()
        {
            boolean wasOpen=isOpen();
            super.close();
            if (wasOpen)
            {
                getConnection().onClose();
                onClose();
            }
        }

        @Override
        public void onClose()
        {
            LocalConnector.this.onEndPointClosed(this);
            super.onClose();
            _closed.countDown();
        }

        @Override
        public void shutdownOutput()
        {
            super.shutdownOutput();
            close();
        }

        public void waitUntilClosed()
        {
            while (isOpen())
            {
                try
                {
                    if (!_closed.await(10,TimeUnit.SECONDS))
                        break;
                }
                catch(Exception e)
                {
                    LOG.warn(e);
                }
            }
        }

        public void waitUntilClosedOrIdleFor(long idleFor,TimeUnit units)
        {
            Thread.yield();
            int size=getOutput().remaining();
            while (isOpen())
            {
                try
                {
                    if (!_closed.await(idleFor,units))
                    {
                        if (size==getOutput().remaining())
                        {
                            if (LOG.isDebugEnabled())
                                LOG.debug("idle for {} {}",idleFor,units);
                            return;
                        }
                        size=getOutput().remaining();
                    }
                }
                catch(Exception e)
                {
                    LOG.warn(e);
                }
            }
        }
        
        /** 
         * Wait for a response using a parser to detect the end of message
         * @return Buffer containing full response or null for EOF;
         * @throws Exception if the response cannot be parsed
         */
        public String getResponse() throws Exception
        {
            return getResponse(false,30,TimeUnit.SECONDS);
        }
        
        /** 
         * Wait for a response using a parser to detect the end of message
         * @param head whether the request is a HEAD request
         * @param time the maximum time to wait
         * @param unit the time unit of the {@code timeout} argument
         * @return Buffer containing full response or null for EOF;
         * @throws Exception if the response cannot be parsed
         */
        public String getResponse(boolean head, long time,TimeUnit unit) throws Exception
        {
            ByteBuffer response = waitForResponse(head,time,unit);
            if (response!=null)
                return BufferUtil.toString(response);
            return null;
        }
        
        /** 
         * Wait for a response using a parser to detect the end of message
         * @param head whether the request is a HEAD request
         * @param time the maximum time to wait
         * @param unit the time unit of the {@code timeout} argument
         * @return Buffer containing full response or null for EOF;
         * @throws Exception if the response cannot be parsed
         */
        public ByteBuffer waitForResponse(boolean head, long time,TimeUnit unit) throws Exception
        {
            HttpParser.ResponseHandler handler = new HttpParser.ResponseHandler()
            {
                @Override
                public void parsedHeader(HttpField field)
                {
                }

                @Override
                public boolean contentComplete()
                {
                    return false;
                }
                
                @Override
                public boolean messageComplete()
                {
                    return true;
                }
                
                @Override
                public boolean headerComplete()
                {
                    return false;
                }
                
                @Override
                public int getHeaderCacheSize()
                {
                    return 0;
                }
                
                @Override
                public void earlyEOF()
                {                
                }
                
                @Override
                public boolean content(ByteBuffer item)
                {
                    return false;
                }
                
                @Override
                public void badMessage(int status, String reason)
                {
                }
                
                @Override
                public boolean startResponse(HttpVersion version, int status, String reason)
                {
                    return false;
                }
            };
            
            HttpParser parser = new HttpParser(handler);
            parser.setHeadResponse(head);
            try(ByteArrayOutputStream2 bout = new ByteArrayOutputStream2();)
            {
                loop: while(true)
                {
                    // read a chunk of response
                    ByteBuffer chunk;
                    if (BufferUtil.hasContent(_responseData))
                        chunk = _responseData;
                    else 
                    {
                        chunk = waitForOutput(time,unit);
                        if (BufferUtil.isEmpty(chunk) && (!isOpen() || isOutputShutdown()))
                        {
                            parser.atEOF();
                            parser.parseNext(BufferUtil.EMPTY_BUFFER);
                            break loop;
                        }
                    }
                    
                    // Parse the content of this chunk
                    while (BufferUtil.hasContent(chunk))
                    {
                        int pos=chunk.position();
                        boolean complete=parser.parseNext(chunk);
                        if (chunk.position()==pos)
                        {
                            // Nothing consumed
                            if (BufferUtil.isEmpty(chunk))
                                break;
                            return null;
                        }

                        // Add all consumed bytes to the output stream
                        bout.write(chunk.array(),chunk.arrayOffset()+pos,chunk.position()-pos);

                        // If we are complete then break the outer loop
                        if (complete)
                        {
                            if (BufferUtil.hasContent(chunk))
                                _responseData=chunk;
                            break loop;
                        }
                    }
                }
            
                if (bout.getCount()==0 && isOutputShutdown())
                    return null;
                return ByteBuffer.wrap(bout.getBuf(),0,bout.getCount()); 
            }
        }
    }
}