/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2019 wcm.io
    * %%
    * Licensed 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.
   * #L%
   */
  package io.wcm.handler.mediasource.dam.impl.metadata;
  
  import static com.day.cq.commons.jcr.JcrConstants.JCR_CONTENT;
  
  import java.util.ArrayList;
  import java.util.List;
  
  import javax.jcr.Node;
  import javax.jcr.RepositoryException;
  import javax.jcr.Session;
  
  import org.apache.commons.lang3.StringUtils;
  import org.apache.sling.api.resource.Resource;
  import org.apache.sling.api.resource.ResourceResolver;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.adobe.granite.workflow.PayloadMap;
  import com.adobe.granite.workflow.collection.ResourceCollection;
  import com.adobe.granite.workflow.collection.ResourceCollectionManager;
  import com.adobe.granite.workflow.exec.WorkItem;
  import com.adobe.granite.workflow.exec.WorkflowData;
  import com.day.cq.wcm.api.NameConstants;
  
  import io.wcm.sling.commons.adapter.AdaptTo;
  
  /**
   * Helper methods for processing workflow payload.
   */
  final class WorkflowProcessUtil {
  
    private static final Logger log = LoggerFactory.getLogger(WorkflowProcessUtil.class);
  
    static final String RT_WORKFLOW_PACKAGE = "cq/workflow/components/collection/page";
  
    private WorkflowProcessUtil() {
      // static methods only
    }
  
    /**
     * Checks if the payload points to a resource path and returns it.
     * @param workItem Work item
     * @return Payload resource path or null
     */
    public static @Nullable String getPayloadResourcePath(@NotNull WorkItem workItem) {
      WorkflowData data = workItem.getWorkflowData();
      if (StringUtils.equals(data.getPayloadType(), PayloadMap.TYPE_JCR_PATH)) {
        return data.getPayload().toString();
      }
      else {
        return null;
      }
    }
  
    /**
     * Get all resource paths paths form workflow payload - either directly referenced in the payload,
     * or a collection of resources referenced via a workflow package.
     * @param payloadPath Payload path
     * @param primaryTypeResourceType JCR primary type or node type, in case of workflow package the result is filtered
     *          to return only matching resources
     * @param resourceResolver Resource resolver
     * @param resourceCollectionManager Resource collection manager
     * @return List of asset paths
     */
    public static @NotNull List<String> getPayloadResourcePaths(@NotNull String payloadPath,
        @NotNull String primaryTypeResourceType,
        @NotNull ResourceResolver resourceResolver,
        @NotNull ResourceCollectionManager resourceCollectionManager) {
      Session session = AdaptTo.notNull(resourceResolver, Session.class);
      List<String> assetPaths = new ArrayList<>();
      try {
        if (session.nodeExists(payloadPath)) {
          Node node = session.getNode(payloadPath);
  
          // check if payload node is a workflow package - collect all matching resources from it
          if (isWorkflowPackagePage(node, resourceResolver)) {
            List<ResourceCollection> resourceCollections = resourceCollectionManager.getCollectionsForNode(node);
            for (ResourceCollection resourceCollection : resourceCollections) {
             for (Node memberNode : resourceCollection.list(new String[] { primaryTypeResourceType })) {
               assetPaths.add(memberNode.getPath());
             }
           }
         }
 
         // otherwise directly return the payload path
         else {
           assetPaths.add(payloadPath);
         }
 
       }
     }
     catch (RepositoryException ex) {
       log.warn("Unable to resolve resource paths from workflow payload: {}", payloadPath, ex);
     }
     return assetPaths;
   }
 
   private static boolean isWorkflowPackagePage(Node node, ResourceResolver resourceResolver) throws RepositoryException {
     if (node.isNodeType(NameConstants.NT_PAGE)) {
       Resource resource = resourceResolver.getResource(node.getPath() + "/" + JCR_CONTENT);
       if (resource != null) {
         return resource.isResourceType(RT_WORKFLOW_PACKAGE);
       }
     }
     return false;
   }
 
 }