/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package org.apache.juneau.xml;

import static org.apache.juneau.common.utils.Utils.*;
import static org.apache.juneau.internal.ClassUtils.*;

import java.util.*;
import java.util.concurrent.*;

import org.apache.juneau.*;
import org.apache.juneau.annotation.*;

/**
 * Represents a simple namespace mapping between a simple name and URI.
 *
 * <p>
 * In general, the simple name will be used as the XML prefix mapping unless there are conflicts or prefix re-mappings
 * in the serializer.
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/XmlBasics">XML Basics</a>
 * </ul>
 */
@Bean(sort=true)
public class Namespace {

   private static final ConcurrentHashMap<String,Namespace> CACHE = new ConcurrentHashMap<>();


   /**
    * Create a {@link Namespace} with the specified name and URI.
    *
    * <p>
    * Previously-encountered name/uri pairs return a cached copy.
    *
    * @param name The namespace name.  See {@link Namespace#getName()}.
    * @param uri The namespace URI.  See {@link Namespace#getUri()}.
    * @return The namespace object.
    */
   public static Namespace of(String name, String uri) {
      String key = name + ":" + uri;
      Namespace n = CACHE.get(key);
      if (n == null) {
         n = new Namespace(key, name, uri);
         Namespace n2 = CACHE.putIfAbsent(key, n);
         return (n2 == null ? n : n2);
      }
      return n;
   }

   /**
    * Create a {@link Namespace} from a <js>"name:uri"</js> string pair.
    *
    * @param key The key/pair string.
    * @return The namespace object.
    */
   public static Namespace of(String key) {
      Namespace n = CACHE.get(key);
      if (n != null)
         return n;
      int i = key.indexOf(':');
      if (i == -1)
         return of(key, null);
      if (key.startsWith("http://") || key.startsWith("https://"))
         return of(null, key);
      return of(key.substring(0, i).trim(), key.substring(i+1).trim());
   }

   /**
    * Converts the specified object into a {@link Namespace} object.
    *
    * <p>
    * Can be any of following types:
    * <ul>
    *    <li>A {@link Namespace} object
    *    <li>A string containing a name/value pair of the form <js>"name:uri"</js>.
    * </ul>
    *
    * @param o The input.
    * @return The namespace object, or <jk>null</jk> if the input was <jk>null</jk> or an empty JSON object.
    */
   public static Namespace create(Object o) {
      if (o == null)
         return null;
      if (o instanceof Namespace)
         return (Namespace)o;
      if (o instanceof CharSequence)
         return of(o.toString());
      throw new BasicRuntimeException("Invalid object type passed to Namespace.create(Object):  ''{0}''", className(o));
   }

   /**
    * Converts the specified object into an array of {@link Namespace} object.
    *
    * <p>
    * Can be any of following types:
    * <ul>
    *    <li>A {@link Namespace} array
    *    <li>A comma-delimited string with key/value pairs of the form <js>"name:uri"</js>.
    *    <li>A <c>Collection</c> containing any of object that can be passed to {@link #createArray(Object)}.
    * </ul>
    *
    * @param o The input.
    * @return The namespace objects, or <jk>null</jk> if the input was <jk>null</jk> or an empty JSON object.
    */
   @SuppressWarnings("rawtypes")
   public static Namespace[] createArray(Object o) {

      if (o instanceof Namespace[])
         return (Namespace[])o;

      if (o instanceof String[]) {
         String[] ss = (String[])o;
         Namespace[] n = new Namespace[ss.length];
         for (int i = 0; i < ss.length; i++)
            n[i] = create(ss[i]);
         return n;
      }

      if (o instanceof CharSequence) {
         String[] ss = splita(o.toString());
         Namespace[] n = new Namespace[ss.length];
         for (int i = 0; i < ss.length; i++)
            n[i] = create(ss[i]);
         return n;
      }

      if (o instanceof Collection) {
         Collection c = (Collection)o;
         Namespace[] n = new Namespace[c.size()];
         int i = 0;
         for (Object o2 : c){
            if (o2 instanceof Namespace)
               n[i++] = (Namespace)o2;
            else if (o2 instanceof CharSequence)
               n[i++] = create(o2.toString());
            else
               throw new BasicRuntimeException("Invalid type passed to NamespaceFactory.createArray: ''{0}''", o);
         }
         return n;
      }

      throw new BasicRuntimeException("Invalid type passed to NamespaceFactory.createArray: ''{0}''", o);
   }


   final String key, name, uri;

   /**
    * Constructor.
    *
    * @param name The short name of this schema.
    * @param uri The URI of this schema.
    */
   private Namespace(String key, String name, String uri) {
      this.key = key;
      this.name = name;
      this.uri = uri;
   }

   /**
    * Returns the namespace name.
    *
    * @return The namespace name.
    */
   public String getName() {
      return name;
   }

   /**
    * Returns the namespace URI.
    *
    * @return The namespace URI.
    */
   public String getUri() {
      return uri;
   }

   @Override /* Object */
   public String toString() {
      return key;
   }
}