/*
 * Copyright (C) 2009 eXo Platform SAS.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.exoplatform.services.rest.impl.resource;

import org.exoplatform.commons.utils.SecurityHelper;
import org.exoplatform.services.log.ExoLogger;
import org.exoplatform.services.log.Log;
import org.exoplatform.services.rest.BaseObjectModel;
import org.exoplatform.services.rest.ComponentLifecycleScope;
import org.exoplatform.services.rest.impl.header.MediaTypeHelper;
import org.exoplatform.services.rest.impl.method.DefaultMethodInvoker;
import org.exoplatform.services.rest.impl.method.MethodInvokerFactory;
import org.exoplatform.services.rest.impl.method.MethodParameterImpl;
import org.exoplatform.services.rest.impl.method.OptionsRequestMethodInvoker;
import org.exoplatform.services.rest.impl.method.ParameterHelper;
import org.exoplatform.services.rest.method.MethodInvoker;
import org.exoplatform.services.rest.method.MethodParameter;
import org.exoplatform.services.rest.resource.AbstractResourceDescriptor;
import org.exoplatform.services.rest.resource.ResourceDescriptorVisitor;
import org.exoplatform.services.rest.resource.ResourceMethodDescriptor;
import org.exoplatform.services.rest.resource.ResourceMethodMap;
import org.exoplatform.services.rest.resource.SubResourceLocatorDescriptor;
import org.exoplatform.services.rest.resource.SubResourceLocatorMap;
import org.exoplatform.services.rest.resource.SubResourceMethodDescriptor;
import org.exoplatform.services.rest.resource.SubResourceMethodMap;
import org.exoplatform.services.rest.uri.UriPattern;

import java.lang.annotation.Annotation;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import javax.ws.rs.Consumes;
import javax.ws.rs.CookieParam;
import javax.ws.rs.DefaultValue;
import javax.ws.rs.Encoded;
import javax.ws.rs.FormParam;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.HttpMethod;
import javax.ws.rs.MatrixParam;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;

/**
 * @author <a href="mailto:andrew00x@gmail.com">Andrey Parfonov</a>
 * @version $Id: $
 */
public class AbstractResourceDescriptorImpl extends BaseObjectModel implements AbstractResourceDescriptor
{
   /** Logger. */
   private static final Log LOG = ExoLogger.getLogger("exo.ws.rest.core.AbstractResourceDescriptorImpl");

   /** @see PathValue */
   private final PathValue path;

   /** @see UriPattern */
   private final UriPattern uriPattern;

   /**
    * Sub-resource methods. Sub-resource method has path annotation.
    * 
    * @see SubResourceMethodDescriptor
    */
   private final SubResourceMethodMap subResourceMethods;

   /**
    * Sub-resource locators. Sub-resource locator has path annotation.
    * 
    * @see SubResourceLocatorDescriptor
    */
   private final SubResourceLocatorMap subResourceLocators;

   /**
    * Resource methods. Resource method has not own path annotation.
    * 
    * @see ResourceMethodDescriptor
    */
   private final ResourceMethodMap<ResourceMethodDescriptor> resourceMethods;

   private final MethodInvokerFactory invokerFactory;

   public AbstractResourceDescriptorImpl(Class<?> resourceClass, ComponentLifecycleScope scope)
   {
      this(resourceClass.getAnnotation(Path.class), resourceClass, scope, null);
   }

   /**
    * Constructs new instance of AbstractResourceDescriptor.
    * 
    * @param resourceClass resource class
    * @param invokerFactory invoker factory
    */
   public AbstractResourceDescriptorImpl(Class<?> resourceClass, MethodInvokerFactory invokerFactory)
   {
      this(resourceClass.getAnnotation(Path.class), resourceClass, ComponentLifecycleScope.PER_REQUEST, invokerFactory);
   }

   /**
    * Constructs new instance of AbstractResourceDescriptor.
    * 
    * @param resource resource instance
    * @param invokerFactory invoker factory
    */
   public AbstractResourceDescriptorImpl(Object resource, MethodInvokerFactory invokerFactory)
   {
      this(resource.getClass().getAnnotation(Path.class), resource.getClass(), ComponentLifecycleScope.SINGLETON,
         invokerFactory);
   }

   /**
    * Constructs new instance of AbstractResourceDescriptor.
    * 
    * @param resourceClass resource class
    */
   public AbstractResourceDescriptorImpl(Class<?> resourceClass)
   {
      this(resourceClass.getAnnotation(Path.class), resourceClass, ComponentLifecycleScope.PER_REQUEST, null);
   }

   /**
    * Constructs new instance of AbstractResourceDescriptor.
    * 
    * @param resource resource instance
    */
   public AbstractResourceDescriptorImpl(Object resource)
   {
      this(resource.getClass().getAnnotation(Path.class), resource.getClass(), ComponentLifecycleScope.SINGLETON, null);
   }

   /**
    * @param path the path value
    * @param resourceClass resource class
    * @param scope resource scope
    * @see ComponentLifecycleScope
    */
   private AbstractResourceDescriptorImpl(Path path, final Class<?> resourceClass, ComponentLifecycleScope scope,
      MethodInvokerFactory invokerFactory)
   {
      super(resourceClass, scope);
      if (path != null)
      {
         this.path = new PathValue(path.value());
         uriPattern = new UriPattern(path.value());
      }
      else
      {
         this.path = null;
         uriPattern = null;
      }
      this.invokerFactory = invokerFactory;
      this.resourceMethods = new ResourceMethodMap<ResourceMethodDescriptor>();
      this.subResourceMethods = new SubResourceMethodMap();
      this.subResourceLocators = new SubResourceLocatorMap();
      processMethods();
   }

   /**
    * {@inheritDoc}
    */
   public void accept(ResourceDescriptorVisitor visitor)
   {
      visitor.visitAbstractResourceDescriptor(this);
   }

   /**
    * {@inheritDoc}
    */
   public PathValue getPathValue()
   {
      return path;
   }

   /**
    * {@inheritDoc}
    */
   public ResourceMethodMap<ResourceMethodDescriptor> getResourceMethods()
   {
      return resourceMethods;
   }

   /**
    * {@inheritDoc}
    */
   public SubResourceLocatorMap getSubResourceLocators()
   {
      return subResourceLocators;
   }

   /**
    * {@inheritDoc}
    */
   public SubResourceMethodMap getSubResourceMethods()
   {
      return subResourceMethods;
   }

   /**
    * {@inheritDoc}
    */
   public UriPattern getUriPattern()
   {
      return uriPattern;
   }

   /**
    * {@inheritDoc}
    */
   public boolean isRootResource()
   {
      return path != null;
   }

   /**
    * Process method of resource and separate them to three types Resource
    * Methods, Sub-Resource Methods and Sub-Resource Locators.
    */
   protected void processMethods()
   {
      final Class<?> resourceClass = getObjectClass();

      Method[] methods = SecurityHelper.doPrivilegedAction(new PrivilegedAction<Method[]>() {
         public Method[] run()
         {
            return resourceClass.getDeclaredMethods();
         }
      });

      for (Method method : methods)
      {
         for (Annotation a : method.getAnnotations())
         {
            Class<?> ac = a.annotationType();
            if (!Modifier.isPublic(method.getModifiers())
               && (ac == CookieParam.class || ac == Consumes.class || ac == Context.class || ac == DefaultValue.class
                  || ac == Encoded.class || ac == FormParam.class || ac == HeaderParam.class || ac == MatrixParam.class
                  || ac == Path.class || ac == PathParam.class || ac == Produces.class || ac == QueryParam.class || ac
                  .getAnnotation(HttpMethod.class) != null))
            {

               LOG.warn("Non-public method at resource " + toString() + " annotated with JAX-RS annotation: " + a);
            }
         }
      }

      for (Method method : resourceClass.getMethods())
      {
         Path subPath = getMethodAnnotation(method, resourceClass, Path.class, false);
         HttpMethod httpMethod = getMethodAnnotation(method, resourceClass, HttpMethod.class, true);

         if (subPath != null || httpMethod != null)
         {
            List<MethodParameter> params = createMethodParametersList(resourceClass, method);
            if (httpMethod != null)
            {

               Produces p = getMethodAnnotation(method, resourceClass, Produces.class, false);
               if (p == null)
               {
                  p = resourceClass.getAnnotation(Produces.class); // from resource
               }
               // class
               List<MediaType> produces = MediaTypeHelper.createProducesList(p);

               Consumes c = getMethodAnnotation(method, resourceClass, Consumes.class, false);
               if (c == null)
               {
                  c = resourceClass.getAnnotation(Consumes.class); // from resource
               }
               // class
               List<MediaType> consumes = MediaTypeHelper.createConsumesList(c);

               if (subPath == null)
               {
                  // resource method
                  ResourceMethodDescriptor res =
                     new ResourceMethodDescriptorImpl(method, httpMethod.value(), params, this, consumes, produces,
                        getMethodInvoker());
                  ResourceMethodDescriptor exist =
                     findMethodResourceMediaType(resourceMethods.getList(httpMethod.value()), res.consumes(),
                        res.produces());
                  if (exist == null)
                  {
                     resourceMethods.add(httpMethod.value(), res);
                  }
                  else
                  {
                     String msg =
                        "Two resource method " + res + " and " + exist
                           + " with the same HTTP method, consumes and produces found.";
                     throw new RuntimeException(msg);
                  }
               }
               else
               {
                  // sub-resource method
                  SubResourceMethodDescriptor subRes =
                     new SubResourceMethodDescriptorImpl(new PathValue(subPath.value()), method, httpMethod.value(),
                        params, this, consumes, produces, getMethodInvoker());
                  SubResourceMethodDescriptor exist = null;
                  ResourceMethodMap<SubResourceMethodDescriptor> rmm =
                     subResourceMethods.getMethodMap(subRes.getUriPattern());
                  // rmm is never null, empty map instead

                  List<SubResourceMethodDescriptor> l = rmm.getList(httpMethod.value());
                  exist =
                     (SubResourceMethodDescriptor)findMethodResourceMediaType(l, subRes.consumes(), subRes.produces());
                  if (exist == null)
                  {
                     rmm.add(httpMethod.value(), subRes);
                  }
                  else
                  {
                     String msg =
                        "Two sub-resource method " + subRes + " and " + exist
                           + " with the same HTTP method, path, consumes and produces found.";
                     throw new RuntimeException(msg);
                  }
               }
            }
            else
            {
               if (subPath != null)
               {
                  // sub-resource locator
                  SubResourceLocatorDescriptor loc =
                     new SubResourceLocatorDescriptorImpl(new PathValue(subPath.value()), method, params, this,
                        getMethodInvoker());
                  if (!subResourceLocators.containsKey(loc.getUriPattern()))
                  {
                     subResourceLocators.put(loc.getUriPattern(), loc);
                  }
                  else
                  {
                     String msg =
                        "Two sub-resource locators " + loc + " and " + subResourceLocators.get(loc.getUriPattern())
                           + " with the same path found.";
                     throw new RuntimeException(msg);
                  }
               }
            }
         }
      }
      // End method processing.
      // Start HEAD and OPTIONS resolving, see JAX-RS (JSR-311) specification
      // section 3.3.5
      resolveHeadRequest();
      resolveOptionsRequest();

      resourceMethods.sort();
      subResourceMethods.sort();
      // sub-resource locators already sorted
   }

   /**
    * Create list of {@link MethodParameter} .
    * 
    * @param resourceClass class
    * @param method See {@link Method}
    * @return list of {@link MethodParameter}
    */
   protected List<MethodParameter> createMethodParametersList(Class<?> resourceClass, Method method)
   {
      Class<?>[] parameterClasses = method.getParameterTypes();
      if (parameterClasses.length == 0)
      {
         return java.util.Collections.emptyList();
      }

      Type[] parameterGenTypes = method.getGenericParameterTypes();
      Annotation[][] annotations = method.getParameterAnnotations();

      List<MethodParameter> params = new ArrayList<MethodParameter>(parameterClasses.length);
      for (int i = 0; i < parameterClasses.length; i++)
      {
         String defaultValue = null;
         Annotation annotation = null;
         boolean encoded = false;

         List<String> allowedAnnotation = ParameterHelper.RESOURCE_METHOD_PARAMETER_ANNOTATIONS;

         for (Annotation a : annotations[i])
         {
            Class<?> ac = a.annotationType();
            if (allowedAnnotation.contains(ac.getName()))
            {

               if (annotation == null)
               {
                  annotation = a;
               }
               else
               {
                  String msg =
                     "JAX-RS annotations on one of method parameters of resource " + toString() + ", method "
                        + method.getName() + " are equivocality. " + "Annotations: " + annotation + " and " + a
                        + " can't be applied to one parameter.";
                  throw new RuntimeException(msg);
               }

            }
            else if (ac == Encoded.class)
            {
               encoded = true;
            }
            else if (ac == DefaultValue.class)
            {
               defaultValue = ((DefaultValue)a).value();
            }
            else
            {
               if (LOG.isDebugEnabled())
               {
                  LOG.debug("Method parameter of resource " + toString() + ", method " + method.getName()
                     + " contains unknown or not valid JAX-RS annotation " + a.toString() + ". It will be ignored.");
               }
            }
         }

         encoded = encoded || resourceClass.getAnnotation(Encoded.class) != null;

         MethodParameter mp =
            new MethodParameterImpl(annotation, annotations[i], parameterClasses[i], parameterGenTypes[i],
               defaultValue, encoded);
         params.add(mp);
      }

      return params;
   }

   /**
    * According to JSR-311:
    * <p>
    * On receipt of a HEAD request an implementation MUST either: 1. Call method
    * annotated with request method designation for HEAD or, if none present, 2.
    * Call method annotated with a request method designation GET and discard
    * any returned entity.
    * </p>
    */
   protected void resolveHeadRequest()
   {

      List<ResourceMethodDescriptor> getRes = resourceMethods.get(HttpMethod.GET);
      if (getRes == null || getRes.size() == 0)
      {
         return; // nothing to do, there is not 'GET' methods
      }

      // If there is no methods for 'HEAD' anyway never return null.
      // Instead null empty List will be returned.
      List<ResourceMethodDescriptor> headRes = resourceMethods.getList(HttpMethod.HEAD);

      for (ResourceMethodDescriptor rmd : getRes)
      {
         if (findMethodResourceMediaType(headRes, rmd.consumes(), rmd.produces()) == null)
         {
            headRes.add(new ResourceMethodDescriptorImpl(rmd.getMethod(), HttpMethod.HEAD, rmd.getMethodParameters(),
               this, rmd.consumes(), rmd.produces(), rmd.getMethodInvoker()));
         }
      }
      for (ResourceMethodMap<SubResourceMethodDescriptor> rmm : subResourceMethods.values())
      {

         List<SubResourceMethodDescriptor> getSubres = rmm.get(HttpMethod.GET);
         if (getSubres == null || getSubres.size() == 0)
         {
            continue; // nothing to do, there is not 'GET' methods
         }

         // If there is no methods for 'HEAD' anyway never return null.
         // Instead null empty List will be returned.
         List<SubResourceMethodDescriptor> headSubres = rmm.getList(HttpMethod.HEAD);

         Iterator<SubResourceMethodDescriptor> i = getSubres.iterator();
         while (i.hasNext())
         {
            SubResourceMethodDescriptor srmd = i.next();
            if (findMethodResourceMediaType(headSubres, srmd.consumes(), srmd.produces()) == null)
            {
               headSubres.add(new SubResourceMethodDescriptorImpl(srmd.getPathValue(), srmd.getMethod(),
                  HttpMethod.HEAD, srmd.getMethodParameters(), this, srmd.consumes(), srmd.produces(),
                  getMethodInvoker()));
            }
         }
      }
   }

   /**
    * According to JSR-311:
    * <p>
    * On receipt of a OPTIONS request an implementation MUST either: 1. Call
    * method annotated with request method designation for OPTIONS or, if none
    * present, 2. Generate an automatic response using the metadata provided by
    * the JAX-RS annotations on the matching class and its methods.
    * </p>
    */
   protected void resolveOptionsRequest()
   {
      List<ResourceMethodDescriptor> o = resourceMethods.getList("OPTIONS");
      if (o.size() == 0)
      {
         List<MethodParameter> mps = Collections.emptyList();
         List<MediaType> consumes = MediaTypeHelper.DEFAULT_TYPE_LIST;
         List<MediaType> produces = new ArrayList<MediaType>(1);
         produces.add(MediaTypeHelper.WADL_TYPE);
         o.add(new OptionsRequestResourceMethodDescriptorImpl(null, "OPTIONS", mps, this, consumes, produces,
            new OptionsRequestMethodInvoker()));
      }
   }

   /**
    * Get all method with at least one annotation which has annotation
    * <i>annotation</i>. It is useful for annotation {@link javax.ws.rs.GET},
    * etc. All HTTP method annotations has annotation {@link HttpMethod}.
    * 
    * @param <T> annotation type
    * @param m method
    * @param annotation annotation class
    * @return list of annotation
    */
   protected <T extends Annotation> T getMetaAnnotation(Method m, Class<T> annotation)
   {
      for (Annotation a : m.getAnnotations())
      {
         T endPoint = null;
         if ((endPoint = a.annotationType().getAnnotation(annotation)) != null)
         {
            return endPoint;
         }
      }
      return null;
   }

   /**
    * Tries to get JAX-RS annotation on method from the root resource class's
    * superclass or implemented interfaces.
    * 
    * @param <T> annotation type
    * @param method method for discovering
    * @param resourceClass class that contains discovered method
    * @param annotationClass annotation type what we are looking for
    * @param metaAnnotation false if annotation should be on method and true in
    *           method should contain annotations that has supplied annotation
    * @return annotation from class or its ancestor or null if nothing found
    */
   protected <T extends Annotation> T getMethodAnnotation(Method method, Class<?> resourceClass,
      Class<T> annotationClass, boolean metaAnnotation)
   {
      T annotation = null;
      if (metaAnnotation)
      {
         annotation = getMetaAnnotation(method, annotationClass);
      }
      else
      {
         annotation = method.getAnnotation(annotationClass);
      }

      if (annotation == null)
      {
         Method inhMethod = null;
         Class<?> superclass = resourceClass.getSuperclass();
         if (superclass != null)
         {
            try
            {
               inhMethod = superclass.getMethod(method.getName(), method.getParameterTypes());
            }
            catch (NoSuchMethodException e)
            {
               if (LOG.isTraceEnabled())
               {
                  LOG.trace("An exception occurred: " + e.getMessage());
               }
            }
         }
         if (inhMethod == null)
         {
            for (Class<?> intf : resourceClass.getInterfaces())
            {
               try
               {

                  Method tmp = intf.getMethod(method.getName(), method.getParameterTypes());
                  if (inhMethod == null)
                  {
                     inhMethod = tmp;
                  }
                  else
                  {
                     String msg =
                        "JAX-RS annotation on method " + inhMethod.getName() + " of resource " + toString()
                           + " is equivocality.";
                     throw new RuntimeException(msg);
                  }
               }
               catch (NoSuchMethodException exc)
               {
                  if (LOG.isTraceEnabled())
                  {
                     LOG.trace("An exception occurred: " + exc.getMessage());
                  }
               }
            }
         }
         if (inhMethod != null)
         {
            if (metaAnnotation)
            {
               annotation = getMetaAnnotation(inhMethod, annotationClass);
            }
            else
            {
               annotation = inhMethod.getAnnotation(annotationClass);
            }
         }
      }

      return annotation;
   }

   /**
    * Check is collection of {@link ResourceMethodDescriptor} already contains
    * ResourceMethodDescriptor with the same media types.
    * 
    * @param rmds {@link Set} of {@link ResourceMethodDescriptor}
    * @param consumes resource method consumed media type
    * @param produces resource method produced media type
    * @return ResourceMethodDescriptor or null if nothing found
    */
   protected <T extends ResourceMethodDescriptor> ResourceMethodDescriptor findMethodResourceMediaType(List<T> rmds,
      List<MediaType> consumes, List<MediaType> produces)
   {

      ResourceMethodDescriptor matched = null;
      for (T rmd : rmds)
      {
         if (rmd.consumes().size() != consumes.size())
         {
            return null;
         }
         if (rmd.produces().size() != produces.size())
         {
            return null;
         }
         for (MediaType c1 : rmd.consumes())
         {
            boolean eq = false;
            for (MediaType c2 : consumes)
            {
               if (c1.equals(c2))
               {
                  eq = true;
                  break;
               }
            }
            if (!eq)
            {
               return null;
            }
         }

         for (MediaType p1 : rmd.produces())
         {
            boolean eq = false;
            for (MediaType p2 : produces)
            {
               if (p1.equals(p2))
               {
                  eq = true;
                  break;
               }
            }
            if (!eq)
            {
               return null;
            }
         }

         matched = rmd; // matched resource method
         break;
      }

      return matched;
   }

   protected MethodInvoker getMethodInvoker()
   {
      if (invokerFactory != null)
      {
         return invokerFactory.getMethodInvoker();
      }
      return new DefaultMethodInvoker();
   }

   /**
    * {@inheritDoc}
    */
   @Override
   public String toString()
   {
      StringBuffer sb = new StringBuffer("[ AbstractResourceDescriptorImpl: ");
      sb.append("path: " + getPathValue()).append("; isRootResource: " + isRootResource())
         .append("; class: " + getObjectClass()).append(" ]");
      return sb.toString();
   }

}
