// ***************************************************************************************************************************
// * 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.msgpack;

import java.io.IOException;
import java.util.*;

import org.apache.juneau.*;
import org.apache.juneau.internal.*;
import org.apache.juneau.serializer.*;
import org.apache.juneau.transform.*;

/**
 * Session object that lives for the duration of a single use of {@link MsgPackSerializer}.
 *
 * <p>
 * This class is NOT thread safe.
 * It is typically discarded after one-time use although it can be reused within the same thread.
 */
public final class MsgPackSerializerSession extends OutputStreamSerializerSession {

   private final MsgPackSerializer ctx;

   /**
    * Create a new session using properties specified in the context.
    *
    * @param ctx
    *    The context creating this session object.
    *    The context contains all the configuration settings for this object.
    * @param args
    *    Runtime arguments.
    *    These specify session-level information such as locale and URI context.
    *    It also include session-level properties that override the properties defined on the bean and
    *    serializer contexts.
    */
   protected MsgPackSerializerSession(MsgPackSerializer ctx, SerializerSessionArgs args) {
      super(ctx, args);
      this.ctx = ctx;
   }

   @Override /* SerializerSession */
   protected void doSerialize(SerializerPipe out, Object o) throws IOException, SerializeException {
      serializeAnything(getMsgPackOutputStream(out), o, getExpectedRootType(o), "root", null);
   }

   /*
    * Converts the specified output target object to an {@link MsgPackOutputStream}.
    */
   private static final MsgPackOutputStream getMsgPackOutputStream(SerializerPipe out) throws IOException {
      Object output = out.getRawOutput();
      if (output instanceof MsgPackOutputStream)
         return (MsgPackOutputStream)output;
      MsgPackOutputStream os = new MsgPackOutputStream(out.getOutputStream());
      out.setOutputStream(os);
      return os;
   }

   /*
    * Workhorse method.
    * Determines the type of object, and then calls the appropriate type-specific serialization method.
    */
   @SuppressWarnings({ "rawtypes" })
   private MsgPackOutputStream serializeAnything(MsgPackOutputStream out, Object o, ClassMeta<?> eType, String attrName, BeanPropertyMeta pMeta) throws IOException, SerializeException {

      if (o == null)
         return out.appendNull();

      if (eType == null)
         eType = object();

      ClassMeta<?> aType;        // The actual type
      ClassMeta<?> sType;        // The serialized type

      aType = push2(attrName, o, eType);
      boolean isRecursion = aType == null;

      // Handle recursion
      if (aType == null) {
         o = null;
         aType = object();
      }
      
      // Handle Optional<X>
      if (isOptional(aType)) {
         o = getOptionalValue(o);
         eType = getOptionalType(eType);
         aType = getClassMetaForObject(o, object());
      }

      sType = aType;
      String typeName = getBeanTypeName(eType, aType, pMeta);

      // Swap if necessary
      PojoSwap swap = aType.getPojoSwap(this);
      if (swap != null) {
         o = swap(swap, o);
         sType = swap.getSwapClassMeta(this);

         // If the getSwapClass() method returns Object, we need to figure out
         // the actual type now.
         if (sType.isObject())
            sType = getClassMetaForObject(o);
      }

      // '\0' characters are considered null.
      if (o == null || (sType.isChar() && ((Character)o).charValue() == 0))
         out.appendNull();
      else if (sType.isBoolean())
         out.appendBoolean((Boolean)o);
      else if (sType.isNumber())
         out.appendNumber((Number)o);
      else if (sType.isBean())
         serializeBeanMap(out, toBeanMap(o), typeName);
      else if (sType.isUri() || (pMeta != null && pMeta.isUri()))
         out.appendString(resolveUri(o.toString()));
      else if (sType.isMap()) {
         if (o instanceof BeanMap)
            serializeBeanMap(out, (BeanMap)o, typeName);
         else
            serializeMap(out, (Map)o, eType);
      }
      else if (sType.isCollection()) {
         serializeCollection(out, (Collection) o, eType);
      }
      else if (sType.isArray()) {
         serializeCollection(out, toList(sType.getInnerClass(), o), eType);
      }
      else if (sType.isReader() || sType.isInputStream()) {
         IOUtils.pipe(o, out);
      }
      else
         out.appendString(toString(o));

      if (! isRecursion)
         pop();
      return out;
   }

   @SuppressWarnings({ "rawtypes", "unchecked" })
   private void serializeMap(MsgPackOutputStream out, Map m, ClassMeta<?> type) throws IOException, SerializeException {

      ClassMeta<?> keyType = type.getKeyType(), valueType = type.getValueType();

      m = sort(m);

      // The map size may change as we're iterating over it, so
      // grab a snapshot of the entries in a separate list.
      List<SimpleMapEntry> entries = new ArrayList<>(m.size());
      for (Map.Entry e : (Set<Map.Entry>)m.entrySet())
         entries.add(new SimpleMapEntry(e.getKey(), e.getValue()));

      out.startMap(entries.size());

      for (SimpleMapEntry e : entries) {
         Object value = e.value;
         Object key = generalize(e.key, keyType);

         serializeAnything(out, key, keyType, null, null);
         serializeAnything(out, value, valueType, null, null);
      }
   }

   private void serializeBeanMap(MsgPackOutputStream out, final BeanMap<?> m, String typeName) throws IOException, SerializeException {

      List<BeanPropertyValue> values = m.getValues(isTrimNullProperties(), typeName != null ? createBeanTypeNameProperty(m, typeName) : null);

      int size = values.size();
      for (BeanPropertyValue p : values)
         if (p.getThrown() != null)
            size--;
      out.startMap(size);

      for (BeanPropertyValue p : values) {
         BeanPropertyMeta pMeta = p.getMeta();
         if (pMeta.canRead()) {
            ClassMeta<?> cMeta = p.getClassMeta();
            String key = p.getName();
            Object value = p.getValue();
            Throwable t = p.getThrown();
            if (t != null)
               onBeanGetterException(pMeta, t);
            else {
               serializeAnything(out, key, null, null, null);
               serializeAnything(out, value, cMeta, key, pMeta);
            }
         }
      }
   }

   private static final class SimpleMapEntry {
      final Object key;
      final Object value;

      SimpleMapEntry(Object key, Object value) {
         this.key = key;
         this.value = value;
      }
   }

   @SuppressWarnings({"rawtypes", "unchecked"})
   private void serializeCollection(MsgPackOutputStream out, Collection c, ClassMeta<?> type) throws IOException, SerializeException {

      ClassMeta<?> elementType = type.getElementType();
      List<Object> l = new ArrayList<>(c.size());

      c = sort(c);
      l.addAll(c);

      out.startArray(l.size());

      for (Object o : l)
         serializeAnything(out, o, elementType, "<iterator>", null);
   }

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

   @Override
   protected final boolean isAddBeanTypes() {
      return ctx.isAddBeanTypes();
   }

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

   @Override /* Session */
   public ObjectMap toMap() {
      return super.toMap()
         .append("MsgPackSerializerSession", new DefaultFilteringObjectMap()
         );
   }
}