/**
    * This file Copyright (c) 2015 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.resourceloader.util;
  
  import info.magnolia.resourceloader.Resource;
  import info.magnolia.resourceloader.ResourceOrigin;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Comparator;
  import java.util.regex.Pattern;
  
  import com.google.common.base.Function;
  import com.google.common.base.Predicate;
  import com.google.common.base.Predicates;
  
  /**
   * Functional-ish {@link Function}, {@link Predicate} and {@link Comparator} implementations that are useful when working with {@link ResourceOrigin} and {@link Resource}, and some more useful ones that had no better place for now.
   * They are used to implement {@link info.magnolia.resourceloader.layered.LayeredResourceOrigin}, but could be reused for filtering and other purposes.
   *
   * // TODO consistent naming -- handle or path
   * Most of this would be completely redundant with Java 8, since all these do is delegate to a given method of the input object: simple method references as lambdas would suffice.
   */
  public class Functions {
      public static Predicate<ResourceOrigin> hasPath(final String path) {
          return new Predicate<ResourceOrigin>() {
              @Override
              public boolean apply(ResourceOrigin input) {
                  return input.hasPath(path);
              }
          };
      }
  
      public static Predicate<Resource> pathEquals(final CharSequence path) {
          return pathMatches(Predicates.equalTo(path));
      }
  
      public static Predicate<Resource> pathStartsWith(final CharSequence pathPrefix) {
          return pathMatches("^" + pathPrefix);
      }
  
      /**
       * @see #pathMatches(Pattern)
       * @see #pathMatches(Predicate)
       */
      public static Predicate<Resource> pathMatches(final String pattern) {
          return pathMatches(Pattern.compile(pattern));
      }
  
      /**
       * Matches if the input {@link Resource}'s handle matches the given pattern.
       * Matches incomplete strings by default, e.g <code>/bar</code> pattern will match the <code>/foo/bar/qux</code> resource,
       * while <code>^/bar</code> won't.
       * @see #pathMatches(String)
       * @see #pathMatches(Predicate)
       */
      public static Predicate<Resource> pathMatches(final Pattern pattern) {
          return pathMatches(Predicates.contains(pattern));
      }
  
      /**
       * @see #pathMatches(String)
       * @see #pathMatches(Pattern)
       */
      public static Predicate<Resource> pathMatches(final Predicate<CharSequence> predicate) {
          return new Predicate<Resource>() {
              @Override
              public boolean apply(Resource input) {
                 return predicate.apply(input.getPath());
             }
         };
     }
 
     public static Predicate<Resource> isDirectory() {
         return new Predicate<Resource>() {
             @Override
             public boolean apply(Resource input) {
                 return input.isDirectory();
             }
         };
     }
 
     public static Predicate<Resource> isFile() {
         return new Predicate<Resource>() {
             @Override
             public boolean apply(Resource input) {
                 return input.isFile();
             }
         };
     }
 
     /**
      * Convenient Predicate which simply delegates to {@link Predicates#alwaysTrue()}, avoids verbose type parameter declaration and provides a (debatably) better name.
      */
     public static Predicate<Resource> always() {
         return Predicates.alwaysTrue();
     }
 
     /**
      * Convenient Predicate which simply delegates to {@link Predicates#alwaysFalse()}, avoids verbose type parameter declaration, and provides a (debatably) better name.
      */
     public static Predicate<Resource> never() {
         return Predicates.alwaysFalse();
     }
 
     public static Function<ResourceOrigin, Resource> getByPath(final String path) {
         return new Function<ResourceOrigin, Resource>() {
             @Override
             public Resource apply(ResourceOrigin origin) {
                 return origin.getByPath(path);
             }
         };
     }
 
     public static Function<ResourceOrigin, Resource> getRoot() {
         return new Function<ResourceOrigin, Resource>() {
             @Override
             public Resource apply(ResourceOrigin origin) {
                 return origin.getRoot();
             }
         };
     }
 
     public static Function<Resource, String> getPath() {
         return new Function<Resource, String>() {
             @Override
             public String apply(Resource input) {
                 return input.getPath();
             }
         };
     }
 
     public static Function<Resource, Resource> getParent() {
         return new Function<Resource, Resource>() {
             @Override
             public Resource apply(Resource input) {
                 return input.getParent();
             }
         };
     }
 
     /**
      * This Function simply collects all input into the given target collection.
      * It adds elements to the given target collection, but it can also be retrieved with {@link CollectorFunction#getTarget()}
      */
     public static <T> CollectorFunction<T> collector(final Collection<T> target) {
         return new CollectorFunction<>(target);
     }
 
     /**
      * This Function simply collects all input into a new collection.
      * The collection can be retrieved with {@link CollectorFunction#getTarget()}
      */
     public static <T> CollectorFunction<T> collector() {
         return new CollectorFunction<>(new ArrayList<T>());
     }
 
     public static <R extends Resource> Comparator<R> compareByHandle() {
         return new Comparator<R>() {
             @Override
             public int compare(R o1, R o2) {
                 return o1.getPath().compareTo(o2.getPath());
             }
         };
     }
 
     /**
      * A simple Function which aggregates arguments from all its invocations.
      */
     public static class CollectorFunction<T> extends VoidFunction<T> {
         private final Collection<T> target;
 
         private CollectorFunction(Collection<T> target) {
             this.target = target;
         }
 
         @Override
         public void doWith(T input) {
             target.add(input);
         }
 
         public Collection<T> getTarget() {
             return target;
         }
     }
 }