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// *                                                                                                                         *
// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
// *                                                                                                                         *
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// ***************************************************************************************************************************
package org.apache.juneau.serializer;

import static java.util.stream.Collectors.*;
import static org.apache.juneau.internal.CollectionUtils.*;
import static org.apache.juneau.internal.ObjectUtils.*;

import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.stream.*;

import org.apache.juneau.*;
import org.apache.juneau.cp.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.reflect.*;

/**
 * Represents a group of {@link Serializer Serializers} that can be looked up by media type.
 *
 * <h5 class='topic'>Description</h5>
 *
 * Provides the following features:
 * <ul class='spaced-list'>
 *    <li>
 *       Finds serializers based on HTTP <c>Accept</c> header values.
 *    <li>
 *       Sets common properties on all serializers in a single method call.
 *    <li>
 *       Clones existing groups and all serializers within the group in a single method call.
 * </ul>
 *
 * <h5 class='topic'>Match ordering</h5>
 *
 * Serializers are matched against <c>Accept</c> strings in the order they exist in this group.
 *
 * <p>
 * Adding new entries will cause the entries to be prepended to the group.
 * This allows for previous serializers to be overridden through subsequent calls.
 *
 * <p>
 * For example, calling <code>g.append(S1.<jk>class</jk>,S2.<jk>class</jk>).append(S3.<jk>class</jk>,S4.<jk>class</jk>)</code>
 * will result in the order <c>S3, S4, S1, S2</c>.
 *
 * <h5 class='section'>Example:</h5>
 * <p class='bjava'>
 *    <jc>// Construct a new serializer group</jc>
 *    SerializerSet <jv>serializers</jv> = SerializerSet.<jsm>create</jsm>();
 *       .add(JsonSerializer.<jk>class</jk>, UrlEncodingSerializer.<jk>class</jk>) <jc>// Add some serializers to it</jc>
 *       .forEach(<jv>x</jv> -&gt; <jv>x</jv>.swaps(TemporalCalendarSwap.IsoLocalDateTime.<jk>class</jk>))
 *       .forEachWS(<jv>x</jv> -&gt; <jv>x</jv>.ws())
 *       .build();
 *
 *    <jc>// Find the appropriate serializer by Accept type</jc>
 *    WriterSerializer <jv>serializer</jv> = <jv>serializers</jv>
 *       .getWriterSerializer(<js>"text/foo, text/json;q=0.8, text/*;q:0.6, *\/*;q=0.0"</js>);
 *
 *    <jc>// Serialize a bean to JSON text </jc>
 *    AddressBook <jv>addressBook</jv> = <jk>new</jk> AddressBook();  <jc>// Bean to serialize.</jc>
 *    String <jv>json</jv> = <jv>serializer</jv>.serialize(<jv>addressBook</jv>);
 * </p>
 *
 * <h5 class='section'>Notes:</h5><ul>
 *    <li class='note'>This class is thread safe and reusable.
 * </ul>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="../../../../index.html#jm.SerializersAndParsers">Serializers and Parsers</a>

 * </ul>
 */
public final class SerializerSet {

   //-----------------------------------------------------------------------------------------------------------------
   // Static
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * An identifier that the previous entries in this group should be inherited.
    * <p>
    * Used by {@link SerializerSet.Builder#set(Class...)}
    */
   @SuppressWarnings("javadoc")
   public static abstract class Inherit extends Serializer {
      public Inherit(Serializer.Builder builder) {
         super(builder);
      }
   }

   /**
    * An identifier that the previous entries in this group should not be inherited.
    * <p>
    * Used by {@link SerializerSet.Builder#add(Class...)}
    */
   @SuppressWarnings("javadoc")
   public static abstract class NoInherit extends Serializer {
      public NoInherit(Serializer.Builder builder) {
         super(builder);
      }
   }

   /**
    * Static creator.
    *
    * @param beanStore The bean store to use for creating beans.
    * @return A new builder for this object.
    */
   public static Builder create(BeanStore beanStore) {
      return new Builder(beanStore);
   }

   /**
    * Static creator.
    *
    * @return A new builder for this object.
    */
   public static Builder create() {
      return new Builder(BeanStore.INSTANCE);
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Builder
   //-----------------------------------------------------------------------------------------------------------------

   /**
    * Builder class.
    */
   @FluentSetters
   public static class Builder extends BeanBuilder<SerializerSet> {

      List<Object> entries;
      private BeanContext.Builder bcBuilder;

      /**
       * Create an empty serializer group builder.
       *
       * @param beanStore The bean store to use for creating beans.
       */
      protected Builder(BeanStore beanStore) {
         super(SerializerSet.class, beanStore);
         this.entries = list();
      }

      /**
       * Clone an existing serializer group.
       *
       * @param copyFrom The serializer group that we're copying settings and serializers from.
       */
      protected Builder(SerializerSet copyFrom) {
         super(copyFrom.getClass());
         this.entries = list((Object[])copyFrom.entries);
      }

      /**
       * Clone an existing serializer group builder.
       *
       * <p>
       * Serializer builders will be cloned during this process.
       *
       * @param copyFrom The serializer group that we're copying settings and serializers from.
       */
      protected Builder(Builder copyFrom) {
         super(copyFrom);
         bcBuilder = copyFrom.bcBuilder == null ? null : copyFrom.bcBuilder.copy();
         entries = list();
         copyFrom.entries.stream().map(this::copyBuilder).forEach(x -> entries.add(x));
      }

      private Object copyBuilder(Object o) {
         if (o instanceof Serializer.Builder) {
            Serializer.Builder x = (Serializer.Builder)o;
            Serializer.Builder x2 = x.copy();
            if (ne(x.getClass(), x2.getClass()))
               throw new BasicRuntimeException("Copy method not implemented on class {0}", x.getClass().getName());
            x = x2;
            if (bcBuilder != null)
               x.beanContext(bcBuilder);
            return x;
         }
         return o;
      }

      @Override /* BeanBuilder */
      protected SerializerSet buildDefault() {
         return new SerializerSet(this);
      }

      /**
       * Makes a copy of this builder.
       *
       * @return A new copy of this builder.
       */
      public Builder copy() {
         return new Builder(this);
      }

      //-------------------------------------------------------------------------------------------------------------
      // Properties
      //-------------------------------------------------------------------------------------------------------------

      /**
       * Associates an existing bean context builder with all serializer builders in this group.
       *
       * @param value The bean contest builder to associate.
       * @return This object.
       */
      public Builder beanContext(BeanContext.Builder value) {
         bcBuilder = value;
         forEach(x -> x.beanContext(value));
         return this;
      }

      /**
       * Applies an operation to the bean context builder.
       *
       * @param operation The operation to apply.
       * @return This object.
       */
      public final Builder beanContext(Consumer<BeanContext.Builder> operation) {
         if (bcBuilder != null)
            operation.accept(bcBuilder);
         return this;
      }

      /**
       * Adds the specified serializers to this group.
       *
       * <p>
       * Entries are added in-order to the beginning of the list in the group.
       *
       * <p>
       * The {@link NoInherit} class can be used to clear out the existing list of serializers before adding the new entries.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    SerializerSet.Builder <jv>builder</jv> = SerializerSet.<jsm>create</jsm>();  <jc>// Create an empty builder.</jc>
       *
       *    <jv>builder</jv>.add(FooSerializer.<jk>class</jk>);  <jc>// Now contains:  [FooSerializer]</jc>
       *
       *    <jv>builder</jv>.add(BarSerializer.<jk>class</jk>, BazSerializer.<jk>class</jk>);  <jc>// Now contains:  [BarParser,BazSerializer,FooSerializer]</jc>
       *
       *    <jv>builder</jv>.add(NoInherit.<jk>class</jk>, QuxSerializer.<jk>class</jk>);  <jc>// Now contains:  [QuxSerializer]</jc>
       * </p>
       *
       * @param values The serializers to add to this group.
       * @return This object.
       * @throws IllegalArgumentException If one or more values do not extend from {@link Serializer}.
       */
      public Builder add(Class<?>...values) {
         List<Object> l = list();
         for (Class<?> e : values) {
            if (Serializer.class.isAssignableFrom(e)) {
               l.add(createBuilder(e));
            } else {
               throw new BasicRuntimeException("Invalid type passed to SerializeGroup.Builder.add(): {0}", e.getName());
            }
         }
         entries.addAll(0, l);
         return this;
      }

      /**
       * Sets the specified serializers for this group.
       *
       * <p>
       * Existing values are overwritten.
       *
       * <p>
       * The {@link Inherit} class can be used to insert existing entries in this group into the position specified.
       *
       * <h5 class='section'>Example:</h5>
       * <p class='bjava'>
       *    SerializerSet.Builder <jv>builder</jv> = SerializerSet.<jsm>create</jsm>();  <jc>// Create an empty builder.</jc>
       *
       *    <jv>builder</jv>.set(FooSerializer.<jk>class</jk>);  <jc>// Now contains:  [FooSerializer]</jc>
       *
       *    <jv>builder</jv>.set(BarSerializer.<jk>class</jk>, BazSerializer.<jk>class</jk>);  <jc>// Now contains:  [BarParser,BazSerializer]</jc>
       *
       *    <jv>builder</jv>.set(Inherit.<jk>class</jk>, QuxSerializer.<jk>class</jk>);  <jc>// Now contains:  [BarParser,BazSerializer,QuxSerializer]</jc>
       * </p>
       *
       * @param values The serializers to set in this group.
       * @return This object.
       * @throws IllegalArgumentException If one or more values do not extend from {@link Serializer} or named <js>"Inherit"</js>.
       */
      public Builder set(Class<?>...values) {
         List<Object> l = list();
         for (Class<?> e : values) {
            if (e.getSimpleName().equals("Inherit")) {
               l.addAll(entries);
            } else if (Serializer.class.isAssignableFrom(e)) {
               l.add(createBuilder(e));
            } else {
               throw new BasicRuntimeException("Invalid type passed to SerializeGroup.Builder.set(): {0}", e.getName());
            }
         }
         entries = l;
         return this;
      }

      private Object createBuilder(Object o) {
         if (o instanceof Class) {

            // Check for no-arg constructor.
            ConstructorInfo ci = ClassInfo.of((Class<?>)o).getPublicConstructor(ConstructorInfo::hasNoParams);
            if (ci != null)
               return ci.invoke();

            // Check for builder create method.
            @SuppressWarnings("unchecked")
            Serializer.Builder b = Serializer.createSerializerBuilder((Class<? extends Serializer>)o);
            if (bcBuilder != null)
               b.beanContext(bcBuilder);
            o = b;
         }
         return o;
      }

      /**
       * Registers the specified serializers with this group.
       *
       * <p>
       * When passing in pre-instantiated serializers to this group, applying properties and transforms to the group
       * do not affect them.
       *
       * @param s The serializers to append to this group.
       * @return This object.
       */
      public Builder add(Serializer...s) {
         prependAll(entries, (Object[])s);
         return this;
      }

      /**
       * Clears out any existing serializers in this group.
       *
       * @return This object.
       */
      public Builder clear() {
         entries.clear();
         return this;
      }

      /**
       * Returns <jk>true</jk> if at least one of the specified annotations can be applied to at least one serializer builder in this group.
       *
       * @param work The work to check.
       * @return <jk>true</jk> if at least one of the specified annotations can be applied to at least one serializer builder in this group.
       */
      public boolean canApply(AnnotationWorkList work) {
         for (Object o : entries)
            if (o instanceof Serializer.Builder)
               if (((Serializer.Builder)o).canApply(work))
                  return true;
         return false;
      }

      /**
       * Applies the specified annotations to all applicable serializer builders in this group.
       *
       * @param work The annotations to apply.
       * @return This object.
       */
      public Builder apply(AnnotationWorkList work) {
         return forEach(x -> x.apply(work));
      }

      /**
       * Performs an action on all serializer builders in this group.
       *
       * @param action The action to perform.
       * @return This object.
       */
      public Builder forEach(Consumer<Serializer.Builder> action) {
         builders(Serializer.Builder.class).forEach(action);
         return this;
      }

      /**
       * Performs an action on all writer serializer builders in this group.
       *
       * @param action The action to perform.
       * @return This object.
       */
      public Builder forEachWS(Consumer<WriterSerializer.Builder> action) {
         return forEach(WriterSerializer.Builder.class, action);
      }

      /**
       * Performs an action on all output stream serializer builders in this group.
       *
       * @param action The action to perform.
       * @return This object.
       */
      public Builder forEachOSS(Consumer<OutputStreamSerializer.Builder> action) {
         return forEach(OutputStreamSerializer.Builder.class, action);
      }

      /**
       * Performs an action on all serializer builders of the specified type in this group.
       *
       * @param <T> The serializer builder type.
       * @param type The serializer builder type.
       * @param action The action to perform.
       * @return This object.
       */
      public <T extends Serializer.Builder> Builder forEach(Class<T> type, Consumer<T> action) {
         builders(type).forEach(action);
         return this;
      }

      /**
       * Returns direct access to the {@link Serializer} and {@link Serializer.Builder} objects in this builder.
       *
       * <p>
       * Provided to allow for any extraneous modifications to the list not accomplishable via other methods on this builder such
       * as re-ordering/adding/removing entries.
       *
       * <p>
       * Note that it is up to the user to ensure that the list only contains {@link Serializer} and {@link Serializer.Builder} objects.
       *
       * @return The inner list of entries in this builder.
       */
      public List<Object> inner() {
         return entries;
      }

      private <T extends Serializer.Builder> Stream<T> builders(Class<T> type) {
         return entries.stream().filter(x -> type.isInstance(x)).map(x -> type.cast(x));
      }

      // <FluentSetters>

      @Override /* GENERATED - org.apache.juneau.BeanBuilder */
      public Builder impl(Object value) {
         super.impl(value);
         return this;
      }

      @Override /* GENERATED - org.apache.juneau.BeanBuilder */
      public Builder type(Class<?> value) {
         super.type(value);
         return this;
      }

      // </FluentSetters>

      //-------------------------------------------------------------------------------------------------------------
      // Other methods
      //-------------------------------------------------------------------------------------------------------------

      @Override /* Object */
      public String toString() {
         return entries.stream().map(this::toString).collect(joining(",","[","]"));
      }

      private String toString(Object o) {
         if (o == null)
            return "null";
         if (o instanceof Serializer.Builder)
            return "builder:" + o.getClass().getName();
         return "serializer:" + o.getClass().getName();
      }
   }

   //-----------------------------------------------------------------------------------------------------------------
   // Instance
   //-----------------------------------------------------------------------------------------------------------------

   // Maps Accept headers to matching serializers.
   private final ConcurrentHashMap<String,SerializerMatch> cache = new ConcurrentHashMap<>();

   private final MediaRange[] mediaRanges;
   private final List<MediaRange> mediaRangesList;
   private final Serializer[] mediaTypeRangeSerializers;

   private final MediaType[] mediaTypes;
   private final List<MediaType> mediaTypesList;
   final Serializer[] entries;
   private final List<Serializer> entriesList;

   /**
    * Constructor.
    *
    * @param builder The builder for this bean.
    */
   protected SerializerSet(Builder builder) {

      this.entries = builder.entries.stream().map(this::build).toArray(Serializer[]::new);
      this.entriesList = ulist(entries);

      List<MediaRange> lmtr = list();
      Set<MediaType> lmt = set();
      List<Serializer> l = list();
      for (Serializer e : entries) {
         e.getMediaTypeRanges().forEachRange(x -> {
            lmtr.add(x);
            l.add(e);
         });
         e.forEachAcceptMediaType(x -> lmt.add(x));
      }

      this.mediaRanges = lmtr.toArray(new MediaRange[lmtr.size()]);
      this.mediaRangesList = ulist(mediaRanges);
      this.mediaTypes = lmt.toArray(new MediaType[lmt.size()]);
      this.mediaTypesList = ulist(mediaTypes);
      this.mediaTypeRangeSerializers = l.toArray(new Serializer[l.size()]);
   }

   private Serializer build(Object o) {
      if (o instanceof Serializer)
         return (Serializer)o;
      return ((Serializer.Builder)o).build();
   }

   /**
    * Creates a copy of this serializer group.
    *
    * @return A new copy of this serializer group.
    */
   public Builder copy() {
      return new Builder(this);
   }

   /**
    * Searches the group for a serializer that can handle the specified <c>Accept</c> value.
    *
    * <p>
    * The <c>accept</c> value complies with the syntax described in RFC2616, Section 14.1, as described below:
    * <p class='bcode'>
    *    Accept         = "Accept" ":"
    *                      #( media-range [ accept-params ] )
    *
    *    media-range    = ( "*\/*"
    *                      | ( type "/" "*" )
    *                      | ( type "/" subtype )
    *                      ) *( ";" parameter )
    *    accept-params  = ";" "q" "=" qvalue *( accept-extension )
    *    accept-extension = ";" token [ "=" ( token | quoted-string ) ]
    * </p>
    *
    * <p>
    * The returned object includes both the serializer and media type that matched.
    *
    * @param acceptHeader The HTTP <l>Accept</l> header string.
    * @return The serializer and media type that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public SerializerMatch getSerializerMatch(String acceptHeader) {
      if (acceptHeader == null)
         return null;
      SerializerMatch sm = cache.get(acceptHeader);
      if (sm != null)
         return sm;

      MediaRanges a = MediaRanges.of(acceptHeader);
      int match = a.match(mediaRangesList);
      if (match >= 0) {
         sm = new SerializerMatch(mediaRanges[match], mediaTypeRangeSerializers[match]);
         cache.putIfAbsent(acceptHeader, sm);
      }

      return cache.get(acceptHeader);
   }

   /**
    * Same as {@link #getSerializerMatch(String)} but matches using a {@link MediaType} instance.
    *
    * @param mediaType The HTTP media type.
    * @return The serializer and media type that matched the media type, or <jk>null</jk> if no match was made.
    */
   public SerializerMatch getSerializerMatch(MediaType mediaType) {
      return getSerializerMatch(mediaType.toString());
   }

   /**
    * Same as {@link #getSerializerMatch(String)} but returns just the matched serializer.
    *
    * @param acceptHeader The HTTP <l>Accept</l> header string.
    * @return The serializer that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public Serializer getSerializer(String acceptHeader) {
      SerializerMatch sm = getSerializerMatch(acceptHeader);
      return sm == null ? null : sm.getSerializer();
   }

   /**
    * Same as {@link #getSerializerMatch(MediaType)} but returns just the matched serializer.
    *
    * @param mediaType The HTTP media type.
    * @return The serializer that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public Serializer getSerializer(MediaType mediaType) {
      if (mediaType == null)
         return null;
      return getSerializer(mediaType.toString());
   }

   /**
    * Same as {@link #getSerializer(String)}, but casts it to a {@link WriterSerializer}.
    *
    * @param acceptHeader The HTTP <l>Accept</l> header string.
    * @return The serializer that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public WriterSerializer getWriterSerializer(String acceptHeader) {
      return (WriterSerializer)getSerializer(acceptHeader);
   }

   /**
    * Same as {@link #getSerializer(MediaType)}, but casts it to a {@link WriterSerializer}.
    *
    * @param mediaType The HTTP media type.
    * @return The serializer that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public WriterSerializer getWriterSerializer(MediaType mediaType) {
      return (WriterSerializer)getSerializer(mediaType);
   }

   /**
    * Same as {@link #getSerializer(String)}, but casts it to an {@link OutputStreamSerializer}.
    *
    * @param acceptHeader The HTTP <l>Accept</l> header string.
    * @return The serializer that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public OutputStreamSerializer getStreamSerializer(String acceptHeader) {
      return (OutputStreamSerializer)getSerializer(acceptHeader);
   }

   /**
    * Same as {@link #getSerializer(MediaType)}, but casts it to a {@link OutputStreamSerializer}.
    *
    * @param mediaType The HTTP media type.
    * @return The serializer that matched the accept header, or <jk>null</jk> if no match was made.
    */
   public OutputStreamSerializer getStreamSerializer(MediaType mediaType) {
      return (OutputStreamSerializer)getSerializer(mediaType);
   }

   /**
    * Returns the media types that all serializers in this group can handle.
    *
    * <p>
    * Entries are ordered in the same order as the serializers in the group.
    *
    * @return An unmodifiable list of media types.
    */
   public List<MediaType> getSupportedMediaTypes() {
      return mediaTypesList;
   }

   /**
    * Returns a copy of the serializers in this group.
    *
    * @return An unmodifiable list of serializers in this group.
    */
   public List<Serializer> getSerializers() {
      return entriesList;
   }

   /**
    * Returns <jk>true</jk> if this group contains no serializers.
    *
    * @return <jk>true</jk> if this group contains no serializers.
    */
   public boolean isEmpty() {
      return entries.length == 0;
   }
}