/*
 * Copyright (c) 2008, 2009, 2011-2013, 2015 Eike Stepper (Berlin, Germany) and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Eike Stepper - initial API and implementation
 */
package org.eclipse.net4j.http.internal.server;

import org.eclipse.net4j.buffer.IBufferHandler;
import org.eclipse.net4j.channel.IChannel;
import org.eclipse.net4j.http.common.IHTTPConnector;
import org.eclipse.net4j.http.internal.common.HTTPConnector;
import org.eclipse.net4j.http.internal.server.bundle.OM;
import org.eclipse.net4j.http.internal.server.messages.Messages;
import org.eclipse.net4j.http.server.INet4jTransportServlet;
import org.eclipse.net4j.protocol.IProtocol;
import org.eclipse.net4j.util.container.IPluginContainer;
import org.eclipse.net4j.util.io.ExtendedDataInputStream;
import org.eclipse.net4j.util.io.ExtendedDataOutputStream;
import org.eclipse.net4j.util.om.trace.ContextTracer;

import org.eclipse.spi.net4j.AcceptorFactory;

import javax.servlet.ServletException;
import javax.servlet.ServletInputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import java.io.IOException;
import java.io.PrintWriter;

/**
 * @author Eike Stepper
 */
public class Net4jTransportServlet extends HttpServlet implements INet4jTransportServlet
{
  private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG, Net4jTransportServlet.class);

  private static final long serialVersionUID = 1L;

  private RequestHandler requestHandler;

  public Net4jTransportServlet()
  {
    if (TRACER.isEnabled())
    {
      TRACER.trace("Creating " + getClass().getName()); //$NON-NLS-1$
    }
  }

  public RequestHandler getRequestHandler()
  {
    return requestHandler;
  }

  public void setRequestHandler(RequestHandler requestHandler)
  {
    this.requestHandler = requestHandler;
  }

  @Override
  protected final void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
  {
    doRequest(req, resp);
  }

  @Override
  protected final void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
  {
    doRequest(req, resp);
  }

  @SuppressWarnings("resource")
  protected void doRequest(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
  {
    if (requestHandler == null)
    {
      throw new ServletException(Messages.getString("Net4jTransportServlet_0")); //$NON-NLS-1$
    }

    String connectorID = req.getParameter("list"); //$NON-NLS-1$
    if (connectorID != null)
    {
      doList(connectorID, resp);
      return;
    }

    ServletInputStream servletInputStream = req.getInputStream();
    ExtendedDataInputStream in = new ExtendedDataInputStream(servletInputStream);

    ServletOutputStream servletOutputStream = resp.getOutputStream();
    ExtendedDataOutputStream out = new ExtendedDataOutputStream(servletOutputStream);

    int opcode = servletInputStream.read();
    switch (opcode)
    {
    case HTTPConnector.OPCODE_CONNECT:
      doConnect(in, out);
      break;

    case HTTPConnector.OPCODE_DISCONNECT:
      doDisconnect(in, out);
      break;

    case HTTPConnector.OPCODE_OPERATIONS:
      doOperations(in, out);
      break;

    default:
      throw new IOException("Invalid opcaode: " + opcode); //$NON-NLS-1$
    }

    out.flush();
  }

  protected void doList(String connectorID, HttpServletResponse resp) throws IOException
  {
    if (TRACER.isEnabled())
    {
      TRACER.format("Received List request: {0}", connectorID); //$NON-NLS-1$
    }

    IHTTPConnector[] connectors = requestHandler.handleList(connectorID);
    PrintWriter writer = resp.getWriter();
    for (IHTTPConnector connector : connectors)
    {
      // TODO Security: Hide connectorID!
      writer.write(connector.getConnectorID());
      writer.write(":"); //$NON-NLS-1$

      String userID = connector.getUserID();
      if (userID != null)
      {
        writer.write(" userID=" + userID); //$NON-NLS-1$
      }

      if (connector instanceof HTTPServerConnector)
      {
        long idleTime = System.currentTimeMillis() - ((HTTPServerConnector)connector).getLastTraffic();
        writer.write(" idleTime=" + idleTime); //$NON-NLS-1$
      }

      writer.write("\n"); //$NON-NLS-1$

      for (IChannel channel : connector.getChannels())
      {
        writer.write("    "); //$NON-NLS-1$
        writer.write(String.valueOf(channel.getID()));
        writer.write(": "); //$NON-NLS-1$
        IBufferHandler receiveHandler = channel.getReceiveHandler();
        if (receiveHandler instanceof IProtocol<?>)
        {
          writer.write(((IProtocol<?>)receiveHandler).getType());
        }
        else
        {
          String string = receiveHandler.toString();
          if (string.length() > 256)
          {
            string = string.substring(0, 256);
          }

          writer.write(string);
        }

        writer.write(" ("); //$NON-NLS-1$
        writer.write(String.valueOf(channel.getID()));
        writer.write(")\n"); //$NON-NLS-1$
      }
    }
  }

  protected void doConnect(ExtendedDataInputStream in, ExtendedDataOutputStream out)
      throws ServletException, IOException
  {
    try
    {
      String userID = in.readString();
      if (TRACER.isEnabled())
      {
        TRACER.format("Received Connect request: {0}", userID); //$NON-NLS-1$
      }

      IHTTPConnector connector = requestHandler.handleConnect(userID);
      out.writeString(connector.getConnectorID());
      out.writeInt(connector.getMaxIdleTime());
    }
    catch (Exception ex)
    {
      OM.LOG.error(ex);
      out.writeString(null);
    }
  }

  protected void doDisconnect(ExtendedDataInputStream in, ExtendedDataOutputStream out)
      throws ServletException, IOException
  {
    try
    {
      String connectorID = in.readString();
      if (TRACER.isEnabled())
      {
        TRACER.format("Received Disconnect request: {0}", connectorID); //$NON-NLS-1$
      }

      requestHandler.handleDisonnect(connectorID);
    }
    catch (Exception ex)
    {
      OM.LOG.error(ex);
    }
  }

  protected void doOperations(ExtendedDataInputStream in, ExtendedDataOutputStream out)
      throws ServletException, IOException
  {
    String connectorID = in.readString();
    if (TRACER.isEnabled())
    {
      TRACER.format("Received Operations request: {0}", connectorID); //$NON-NLS-1$
    }

    requestHandler.handleOperations(connectorID, in, out);
  }

  /**
   * @author Eike Stepper
   */
  public static class ContainerAware extends Net4jTransportServlet
  {
    private static final String ACCEPTORS_GROUP = AcceptorFactory.PRODUCT_GROUP;

    private static final String HTTP_TYPE = HTTPAcceptorFactory.TYPE;

    private static final long serialVersionUID = 1L;

    private HTTPAcceptor acceptor;

    public ContainerAware()
    {
    }

    @Override
    public void init() throws ServletException
    {
      super.init();

      acceptor = (HTTPAcceptor)IPluginContainer.INSTANCE.getElement(ACCEPTORS_GROUP, HTTP_TYPE, null);
      if (acceptor == null)
      {
        throw new ServletException(Messages.getString("Net4jTransportServlet_1")); //$NON-NLS-1$
      }

      acceptor.setServlet(this);
      setRequestHandler(acceptor);
    }

    @Override
    public void destroy()
    {
      setRequestHandler(null);
      acceptor.setServlet(null);
      acceptor = null;
      super.destroy();
    }
  }
}