package org.jboss.resteasy.plugins.server.netty;

import java.io.IOException;
import java.io.InputStream;
import java.net.InetSocketAddress;
import java.util.Date;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;

import javax.ws.rs.ServiceUnavailableException;
import javax.ws.rs.container.AsyncResponse;
import javax.ws.rs.core.HttpHeaders;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.core.Response;

import org.jboss.resteasy.core.AbstractAsynchronousResponse;
import org.jboss.resteasy.core.AbstractExecutionContext;
import org.jboss.resteasy.core.ResteasyContext;
import org.jboss.resteasy.core.ResteasyContext.CloseableContext;
import org.jboss.resteasy.core.SynchronousDispatcher;
import org.jboss.resteasy.plugins.server.BaseHttpRequest;
import org.jboss.resteasy.plugins.server.netty.i18n.Messages;
import org.jboss.resteasy.specimpl.ResteasyHttpHeaders;
import org.jboss.resteasy.specimpl.ResteasyUriInfo;
import org.jboss.resteasy.spi.NotImplementedYetException;
import org.jboss.resteasy.spi.ResteasyAsynchronousContext;
import org.jboss.resteasy.spi.ResteasyAsynchronousResponse;
import org.jboss.resteasy.spi.RunnableWithException;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.ByteBufInputStream;
import io.netty.channel.ChannelHandlerContext;

/**
 * Abstraction for an inbound http request on the server, or a response from a server to a client
 * <p>
 * We have this abstraction so that we can reuse marshalling objects in a client framework and serverside framework
 *
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @author Norman Maurer
 * @author Kristoffer Sjogren
 * @version $Revision: 1 $
 */
public class NettyHttpRequest extends BaseHttpRequest
{
   protected ResteasyHttpHeaders httpHeaders;
   protected SynchronousDispatcher dispatcher;
   protected String httpMethod;
   protected InputStream inputStream;
   protected Map<String, Object> attributes = new HashMap<String, Object>();
   protected NettyHttpResponse response;
   private final boolean is100ContinueExpected;
   private NettyExecutionContext executionContext;
   private final ChannelHandlerContext ctx;
   private volatile boolean flushed;
   private ByteBuf content;

   public NettyHttpRequest(final ChannelHandlerContext ctx, final ResteasyHttpHeaders httpHeaders, final ResteasyUriInfo uri, final String httpMethod, final SynchronousDispatcher dispatcher, final NettyHttpResponse response, final boolean is100ContinueExpected)
   {
      super(uri);
      this.is100ContinueExpected = is100ContinueExpected;
      this.response = response;
      this.dispatcher = dispatcher;
      this.httpHeaders = httpHeaders;
      this.httpMethod = httpMethod;
      this.executionContext = new NettyExecutionContext(this, response, dispatcher);
      this.ctx = ctx;
   }

   @Override
   public MultivaluedMap<String, String> getMutableHeaders()
   {
      return httpHeaders.getMutableHeaders();
   }

   @Override
   public void setHttpMethod(String method)
   {
      this.httpMethod = method;
   }

   @Override
   public Enumeration<String> getAttributeNames()
   {
      Enumeration<String> en = new Enumeration<String>()
      {
         private Iterator<String> it = attributes.keySet().iterator();
         @Override
         public boolean hasMoreElements()
         {
            return it.hasNext();
         }

         @Override
         public String nextElement()
         {
            return it.next();
         }
      };
      return en;
   }

   @Override
   public ResteasyAsynchronousContext getAsyncContext()
   {
      return executionContext;
   }

   public boolean isFlushed()
   {
      return flushed;
   }

   @Override
   public Object getAttribute(String attribute)
   {
      return attributes.get(attribute);
   }

   @Override
   public void setAttribute(String name, Object value)
   {
      attributes.put(name, value);
   }

   @Override
   public void removeAttribute(String name)
   {
      attributes.remove(name);
   }

   @Override
   public HttpHeaders getHttpHeaders()
   {
      return httpHeaders;
   }

   @Override
   public InputStream getInputStream()
   {
      return inputStream;
   }

   @Override
   public void setInputStream(InputStream stream)
   {
      this.inputStream = stream;
   }

   @Override
   public String getHttpMethod()
   {
      return httpMethod;
   }

   public NettyHttpResponse getResponse()
   {
      return response;
   }

   public boolean isKeepAlive()
   {
      return response.isKeepAlive();
   }

   public boolean is100ContinueExpected()
   {
      return is100ContinueExpected;
   }

   @Override
   public void forward(String path)
   {
      throw new NotImplementedYetException();
   }

   @Override
   public boolean wasForwarded()
   {
      return false;
   }

   public void setContentBuffer(ByteBuf content) {
      this.content = content;
      this.inputStream = new ByteBufInputStream(content);
   }

   public void releaseContentBuffer() {
      if (content != null) {
         this.content.release();
      }
   }

   class NettyExecutionContext extends AbstractExecutionContext {
      protected final NettyHttpRequest request;
      protected final NettyHttpResponse response;
      protected volatile boolean done;
      protected volatile boolean cancelled;
      protected volatile boolean wasSuspended;
      protected NettyHttpAsyncResponse asyncResponse;

      NettyExecutionContext(final NettyHttpRequest request, final NettyHttpResponse response, final SynchronousDispatcher dispatcher)
      {
         super(dispatcher, request, response);
         this.request = request;
         this.response = response;
         this.asyncResponse = new NettyHttpAsyncResponse(dispatcher, request, response);
      }

      @Override
      public boolean isSuspended() {
         return wasSuspended;
      }

      @Override
      public ResteasyAsynchronousResponse getAsyncResponse() {
         return asyncResponse;
      }

      @Override
      public ResteasyAsynchronousResponse suspend() throws IllegalStateException {
         return suspend(-1);
      }

      @Override
      public ResteasyAsynchronousResponse suspend(long millis) throws IllegalStateException {
         return suspend(millis, TimeUnit.MILLISECONDS);
      }

      @Override
      public ResteasyAsynchronousResponse suspend(long time, TimeUnit unit) throws IllegalStateException {
         if (wasSuspended)
         {
            throw new IllegalStateException(Messages.MESSAGES.alreadySuspended());
         }
         wasSuspended = true;
         return asyncResponse;
      }

      @Override
      public void complete() {
         if (wasSuspended) {
            asyncResponse.complete();
         }
      }

      @Override
      public CompletionStage<Void> executeAsyncIo(CompletionStage<Void> f) {
          // check if this CF is already resolved
          CompletableFuture<Void> ret = f.toCompletableFuture();
          // if it's not resolved, we may need to suspend
          if(!ret.isDone() && !isSuspended()) {
              suspend();
          }
          return ret;
      }

      @Override
      public CompletionStage<Void> executeBlockingIo(RunnableWithException f, boolean hasInterceptors) {
          if(!NettyUtil.isIoThread()) {
              // we're blocking
              try {
                  f.run();
              } catch (Exception e) {
                  CompletableFuture<Void> ret = new CompletableFuture<>();
                  ret.completeExceptionally(e);
                  return ret;
              }
              return CompletableFuture.completedFuture(null);
          } else if(!hasInterceptors) {
              Map<Class<?>, Object> context = ResteasyContext.getContextDataMap();
              // turn any sync request into async
              if(!isSuspended()) {
                  suspend();
              }
              return CompletableFuture.runAsync(() -> {
                  try(CloseableContext newContext = ResteasyContext.addCloseableContextDataLevel(context)){
                      f.run();
                  } catch (RuntimeException e) {
                      throw e;
                  } catch (Exception e) {
                      throw new RuntimeException(e);
                  }
              });
          } else {
             CompletableFuture<Void> ret = new CompletableFuture<>();
             ret.completeExceptionally(new RuntimeException("Cannot use blocking IO with interceptors when we're on the IO thread"));
             return ret;
          }
      }

      /**
       * Netty implementation of {@link AsyncResponse}.
       *
       * @author Kristoffer Sjogren
       */
      class NettyHttpAsyncResponse extends AbstractAsynchronousResponse {
         private final Object responseLock = new Object();
         protected ScheduledFuture timeoutFuture;
         private NettyHttpResponse nettyResponse;
         NettyHttpAsyncResponse(final SynchronousDispatcher dispatcher, final NettyHttpRequest request, final NettyHttpResponse response) {
            super(dispatcher, request, response);
            this.nettyResponse = response;
         }

         @Override
         public void initialRequestThreadFinished() {
         // done
         }

         @Override
         public void complete() {
            synchronized (responseLock)
            {
               if (done) return;
               if (cancelled) return;
               done = true;
               nettyFlush();
            }
         }


         @Override
         public boolean resume(Object entity) {
            synchronized (responseLock)
            {
               if (done) return false;
               if (cancelled) return false;
               done = true;
               return internalResume(entity, t -> nettyFlush());
            }
         }

         @Override
         public boolean resume(Throwable ex) {
            synchronized (responseLock)
            {
               if (done) return false;
               if (cancelled) return false;
               done = true;
               return internalResume(ex, t -> nettyFlush());
            }
         }

         @Override
         public boolean cancel() {
            synchronized (responseLock)
            {
               if (cancelled) {
                  return true;
               }
               if (done) {
                  return false;
               }
               done = true;
               cancelled = true;
               return internalResume(Response.status(Response.Status.SERVICE_UNAVAILABLE).build(), t -> nettyFlush());
            }
         }

         @Override
         public boolean cancel(int retryAfter) {
            synchronized (responseLock)
            {
               if (cancelled) return true;
               if (done) return false;
               done = true;
               cancelled = true;
               return internalResume(Response.status(Response.Status.SERVICE_UNAVAILABLE).header(HttpHeaders.RETRY_AFTER, retryAfter).build(),
                  t -> nettyFlush());
            }
         }

         protected synchronized void nettyFlush()
         {
            flushed = true;
            try
            {
               nettyResponse.finish();
            }
            catch (IOException e)
            {
               throw new RuntimeException(e);
            }
         }

         @Override
         public boolean cancel(Date retryAfter) {
            synchronized (responseLock)
            {
               if (cancelled) return true;
               if (done) return false;
               done = true;
               cancelled = true;
               return internalResume(Response.status(Response.Status.SERVICE_UNAVAILABLE).header(HttpHeaders.RETRY_AFTER, retryAfter).build(),
                  t -> nettyFlush());
            }
         }

         @Override
         public boolean isSuspended() {
            return !done && !cancelled;
         }

         @Override
         public boolean isCancelled() {
            return cancelled;
         }

         @Override
         public boolean isDone() {
            return done;
         }

         @Override
         public boolean setTimeout(long time, TimeUnit unit) {
            synchronized (responseLock)
            {
               if (done || cancelled) return false;
               if (timeoutFuture != null  && !timeoutFuture.cancel(false)) {
                  return false;
               }
               Runnable task = new Runnable() {
                  @Override
                  public void run()
                  {
                     handleTimeout();
                  }
               };
               timeoutFuture = ctx.executor().schedule(task, time, unit);
            }
            return true;
         }

         protected void handleTimeout()
         {
            if (timeoutHandler != null)
            {
               timeoutHandler.handleTimeout(this);
               return;
            }
            if (done) return;
            resume(new ServiceUnavailableException());
         }
      }
   }

   @Override
   public String getRemoteHost()
   {
      return ((InetSocketAddress)ctx.channel().remoteAddress()).getHostName();
   }

   @Override
   public String getRemoteAddress()
   {
      return ((InetSocketAddress)ctx.channel().remoteAddress()).getAddress().getHostAddress();
   }
}
