/*
 *  Licensed to the Apache Software Foundation (ASF) under one
 *  or more contributor license agreements.  See the NOTICE file
 *  distributed with this work for additional information
 *  regarding copyright ownership.  The ASF licenses this file
 *  to you under the Apache License, Version 2.0 (the
 *  "License"); you may not use this file except in compliance
 *  with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing,
 *  software distributed under the License is distributed on an
 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 *  KIND, either express or implied.  See the License for the
 *  specific language governing permissions and limitations
 *  under the License.
 *
 */
package org.apache.asyncweb.server.context;


import java.net.InetSocketAddress;
import java.util.ArrayList;

import org.apache.asyncweb.common.*;
import org.apache.asyncweb.common.HttpResponse;
import org.apache.asyncweb.common.HttpResponseStatus;
import org.apache.asyncweb.common.MutableHttpResponse;
import org.apache.asyncweb.server.HttpServiceContext;
import org.apache.asyncweb.server.HttpSession;
import org.apache.asyncweb.server.ServiceContainer;
import org.apache.asyncweb.server.HttpClientListener;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;


/**
 * A default implementation of {@link HttpServiceContext}.
 *
 * @author The Apache MINA Project (dev@mina.apache.org)
 */
public abstract class AbstractHttpServiceContext implements HttpServiceContext
{
    private final Logger log = LoggerFactory.getLogger( AbstractHttpServiceContext.class );

    private final InetSocketAddress remoteAddress;
    
    private final InetSocketAddress localAddress;

    private final HttpRequest request;

    private HttpResponse committedResponse;

    private HttpSession session;

    private boolean createdSession;

    private final ServiceContainer container;

    private final ArrayList<HttpClientListener> listeners = new ArrayList<HttpClientListener>( 2 );


    public AbstractHttpServiceContext( InetSocketAddress localAddress, InetSocketAddress remoteAddress,
                                       HttpRequest request, ServiceContainer container )
    {
        if ( remoteAddress == null )
        {
            throw new NullPointerException( "remoteAddress" );
        }

        if ( localAddress == null )
        {
            throw new NullPointerException( "localAddress" );
        }
        
        if ( request == null )
        {
            throw new NullPointerException( "request" );
        }

        if ( container == null )
        {
            throw new NullPointerException( "container" );
        }

        this.remoteAddress = remoteAddress;
        this.localAddress = localAddress;
        this.request = request;
        this.container = container;
        this.session = container.getSessionAccessor().getSession( this, false );
    }


    public synchronized boolean isResponseCommitted()
    {
        return committedResponse != null;
    }


    /**
     * Commits a <code>HttpResponse</code> to this <code>Request</code>.
     *
     * @param response  The response to commit
     * @return <code>true</code> iff the response was committed
     */
    public boolean commitResponse( HttpResponse response )
    {
        synchronized ( this )
        {
            if ( isResponseCommitted() )
            {
                log.info( "Request already comitted to a response. Disposing response" );
                return false;
            }

            committedResponse = response;
        }

        // Add the session identifier if the session was newly created.
        if ( createdSession )
        {
            container.getSessionAccessor().addSessionIdentifier( this, ( MutableHttpResponse ) response );
        }

        // Only parsed requests can be formatted.
        if ( getRequest().getMethod() != null )
        {
            container.getErrorResponseFormatter().formatResponse( getRequest(), ( MutableHttpResponse ) response );
        }

        if ( container.isSendServerHeader() )
        {
            ( ( MutableHttpResponse ) response ).setHeader( HttpHeaderConstants.KEY_SERVER, "AsyncWeb" );
        }

        // Normalize the response.
        ( ( MutableHttpResponse ) response ).normalize( getRequest() );

        // Override connection header if needed.
        if ( ! container.getKeepAliveStrategy().keepAlive( this, response ) )
        {
            ( ( MutableHttpResponse ) response ).setHeader( HttpHeaderConstants.KEY_CONNECTION,
                    HttpHeaderConstants.VALUE_CLOSE );
        }

        boolean requiresClosure = ! HttpHeaderConstants.VALUE_KEEP_ALIVE
                .equalsIgnoreCase( response.getHeader(HttpHeaderConstants.KEY_CONNECTION ) );

        if ( requiresClosure && log.isDebugEnabled() )
        {
            log.debug("Response status: " + response.getStatus());
            log.debug("Keep-alive strategy requires closure of "
                    + getRemoteAddress());
        }

        if ( log.isDebugEnabled() )
        {
            log.debug( "Committing a response:" );
            log.debug( "Status: " + response.getStatus() + ' ' + response.getStatusReasonPhrase() );
            log.debug( "Headers: " + response.getHeaders() );
        }

        doWrite( requiresClosure );
        return true;
    }


    public boolean commitResponse( HttpResponseStatus status )
    {
        MutableHttpResponse response = new DefaultHttpResponse();
        response.setStatus( status );
        return commitResponse( response );
    }


    public synchronized HttpResponse getCommittedResponse()
    {
        return committedResponse;
    }


    public InetSocketAddress getRemoteAddress()
    {
        return remoteAddress;
    }

    public InetSocketAddress getLocalAddress()
    {
        return localAddress;
    }


    public HttpRequest getRequest()
    {
        return request;
    }


    public HttpSession getSession()
    {
        return getSession( true );
    }

    
    public synchronized HttpSession getSession( boolean create )
    {
        if ( session != null && ! session.isValid() )
        {
            session = null;
        }

        if ( session == null )
        {
            session = container.getSessionAccessor().getSession( this, create );
            if ( create )
            {
                createdSession = true;
            }
        }

        return session;
    }


    protected void fireClientDisconnected()
    {
        ArrayList<HttpClientListener> cloned;
        synchronized( listeners )
        {
            //noinspection unchecked
            cloned = ( ArrayList<HttpClientListener> ) listeners.clone();
        }

        for ( HttpClientListener listener : cloned )
        {
            listener.clientDisconnected( this );
        }
    }


    protected void fireClientIdle( long idleTime, int idleCount )
    {
        ArrayList<HttpClientListener> cloned;
        synchronized( listeners )
        {
            //noinspection unchecked
            cloned = ( ArrayList<HttpClientListener> ) listeners.clone();
        }

        for ( HttpClientListener listener : cloned )
        {
            listener.clientIdle( this, idleTime, idleCount );
        }
    }


    public boolean addClientListener( HttpClientListener listener )
    {
        return listeners.add( listener );
    }


    public boolean removeClientListener( HttpClientListener listener )
    {
        return listeners != null && listeners.remove( listener );
    }


    protected abstract void doWrite( boolean requiresClosure );
}