/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2014 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.link;
  
  import java.util.HashMap;
  
  import org.apache.commons.lang3.builder.ToStringBuilder;
  import org.apache.sling.api.resource.Resource;
  import org.apache.sling.api.resource.ValueMap;
  import org.apache.sling.api.wrappers.ValueMapDecorator;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  import org.osgi.annotation.versioning.ProviderType;
  
  import com.day.cq.wcm.api.Page;
  
  import io.wcm.wcm.commons.util.ToStringStyle;
  
  /**
   * Holds all properties that are part of a link handling request.
   */
  @ProviderType
  public final class LinkRequest {
  
    private final Resource resource;
    private final Page page;
    private final String reference;
    private final LinkArgs linkArgs;
  
    private ValueMap resourceProperties;
  
    /**
     * @param resource Resource containing properties that define the link target
     * @param page Target content page
     * @param linkArgs Link arguments
     */
    public LinkRequest(@Nullable Resource resource, @Nullable Page page, @Nullable LinkArgs linkArgs) {
      this(resource, page, null, linkArgs);
    }
  
    /**
     * @param resource Resource containing properties that define the link target
     * @param page Target content page
     * @param reference Link reference (internal or external).
     * @param linkArgs Link arguments
     */
    public LinkRequest(@Nullable Resource resource, @Nullable Page page, @Nullable String reference, @Nullable LinkArgs linkArgs) {
      this.resource = resource;
      this.page = page;
      this.reference = reference;
      this.linkArgs = linkArgs != null ? linkArgs : new LinkArgs();
  
      // validate parameters
      int linkParamCount = (resource != null ? 1 : 0)
          + (page != null ? 1 : 0)
          + (reference != null ? 1 : 0);
      if (linkParamCount > 1) {
        throw new IllegalArgumentException("Set only one of resource, page, or reference.");
      }
    }
  
    /**
     * @return Resource containing properties that define the link target
     */
    public @Nullable Resource getResource() {
      return this.resource;
    }
  
    /**
     * @return Target content page
     */
    public @Nullable Page getPage() {
      return this.page;
    }
  
    /**
     * @return Link reference (internal or external).
     */
    public @Nullable String getReference() {
      return this.reference;
    }
  
   /**
    * @return Link arguments
    */
   public @NotNull LinkArgs getLinkArgs() {
     return this.linkArgs;
   }
 
   /**
    * @return Properties from resource containing target link. The value map is a copy
    *         of the original map so it is safe to change the property values contained in the map.
    */
   public @NotNull ValueMap getResourceProperties() {
     if (this.resourceProperties == null) {
       // create a copy of the original map
       this.resourceProperties = new ValueMapDecorator(new HashMap<>());
       if (this.resource != null) {
         this.resourceProperties.putAll(resource.getValueMap());
       }
     }
     return this.resourceProperties;
   }
 
   @Override
   public String toString() {
     return ToStringBuilder.reflectionToString(this, ToStringStyle.SHORT_PREFIX_OMIT_NULL_STYLE);
   }
 
 }