/**
    * This file Copyright (c) 2018 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.ui.framework.ioc;
  
  import info.magnolia.objectfactory.ParameterInfo;
  import info.magnolia.objectfactory.ParameterResolver;
  import info.magnolia.ui.framework.ContextProperty;
  import info.magnolia.ui.framework.LeakagePreventingWrapper;
  import info.magnolia.ui.framework.UiFrameworkView;
  import info.magnolia.ui.framework.ViewContext;
  import info.magnolia.ui.framework.ViewContextBase;
  import info.magnolia.ui.framework.ViewContextProxy;
  
  import java.util.Arrays;
  import java.util.Map;
  import java.util.Objects;
  import java.util.Optional;
  import java.util.stream.Collectors;
  
  import javax.inject.Provider;
  
  /**
   * Looks-up instances in {@link BeanStore session bean stores}. Search starts
   * at the bean store linked to the current view and may propagate to all the parents.
   *
   * If the searched parameter type implements {@link ViewContext}, the resolved instance is
   * wrapped into a memory-leak safe-guard proxy, which will unsubscribe all the context listeners
   * once the current view is destroyed.
   *
   * @see UiFrameworkView
   * @see ViewComponentProvider
   * @see SessionStore
   */
  class ViewContextParameterResolver implements ParameterResolver {
  
      private final static Class[] BLACK_LIST = new Class[] { Provider.class, com.google.inject.Provider.class };
  
      private final UiContextReference uiContextReference;
  
      ViewContextParameterResolver(UiContextReference uiContextReference) {
          this.uiContextReference = uiContextReference;
      }
  
      @Override
      @SuppressWarnings("unchecked")
      public Object resolveParameter(ParameterInfo parameter) {
          final Class<?> parameterType = parameter.getParameterType();
  
          // Check whether the type that is being resolved is not blacklisted. E.g. we blacklist the IoC provider objects,
          // because they might end up in the bean store (via Guice scoping) and they might be accidentally accessed by this
          // parameter resolver, but the wrong one might be chosen as suitable candidate (due to the erasure of the generic info) and
          // it is generally better to let the Guice parameter resolver to take care of providers.
          boolean isBlackListed = Arrays.stream(BLACK_LIST).anyMatch(blackListedType -> blackListedType.isAssignableFrom(parameterType));
          if (isBlackListed) {
              return ParameterResolver.UNRESOLVED;
          }
  
          return lookup(parameterType);
      }
  
      private Object lookup(Class<?> parameterType) {
          final BeanStore beanStore = SessionStore.access().getBeanStore(uiContextReference);
          final Optional<Object> valueFromCurrentStore = Optional.ofNullable(beanStore.getClosestInstance(parameterType));
  
          final Object param = valueFromCurrentStore.orElseGet(() -> uiContextReference.getParentReferences().stream()
                  .map(parentRef -> SessionStore.access().getBeanStore(parentRef))
                  .map(parentStore -> parentStore.getClosestInstance(parameterType))
                  .filter(Objects::nonNull)
                 .findFirst()
                 .map(parameter -> parameter instanceof ViewContext ? wrapViewContext((ViewContext) parameter) : parameter)
                 .orElse(ParameterResolver.UNRESOLVED));
 
         if ((param instanceof ViewContext) && !valueFromCurrentStore.isPresent()) {
             final ViewContext wrappedViewContext = wrapViewContext((ViewContext) param);
             beanStore.put(parameterType, wrappedViewContext);
             return wrappedViewContext;
         }
 
         return param;
     }
 
     private ViewContext wrapViewContext(ViewContext viewContext) {
         final ViewContextBase baseViewContext = (ViewContextBase) viewContext;
         final Map<String, ContextProperty> properties = baseViewContext.properties();
         final Map<String, ContextProperty> wrappedProperties =
                         properties.entrySet()
                         .stream()
                         .collect(Collectors.toMap(Map.Entry::getKey, entry -> {
                             final ContextProperty<?> contextProperty = entry.getValue();
                             return new LeakagePreventingWrapper<>(contextProperty);
                         }));
 
         return new ViewContextProxy().createViewContext(baseViewContext.getViewContextType(), wrappedProperties);
     }
 }