/*
 * 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 static org.apache.juneau.commons.utils.AssertionUtils.*;
import static org.apache.juneau.commons.utils.CollectionUtils.*;
import static org.apache.juneau.commons.utils.IoUtils.*;
import static org.apache.juneau.commons.utils.Utils.*;

import java.io.*;
import java.lang.reflect.*;
import java.util.*;
import java.util.function.*;

import org.apache.juneau.*;
import org.apache.juneau.httppart.*;
import org.apache.juneau.serializer.*;
import org.apache.juneau.svl.*;

/**
 * Session object that lives for the duration of a single use of {@link MsgPackSerializer}.
 *
 * <h5 class='section'>Notes:</h5><ul>
 *    <li class='warn'>This class is not thread safe and is typically discarded after one use.
 * </ul>
 *
 * <h5 class='section'>See Also:</h5><ul>
 *    <li class='link'><a class="doclink" href="https://juneau.apache.org/docs/topics/MessagePackBasics">MessagePack Basics</a>

 * </ul>
 */
@SuppressWarnings("resource")
public class MsgPackSerializerSession extends OutputStreamSerializerSession {
   /**
    * Builder class.
    */
   public static class Builder extends OutputStreamSerializerSession.Builder {

      private MsgPackSerializer ctx;

      /**
       * Constructor
       *
       * @param ctx The context creating this session.
       *    <br>Cannot be <jk>null</jk>.
       */
      protected Builder(MsgPackSerializer ctx) {
         super(assertArgNotNull("ctx", ctx));
         this.ctx = ctx;
      }

      @Override /* Overridden from Builder */
      public <T> Builder apply(Class<T> type, Consumer<T> apply) {
         super.apply(type, apply);
         return this;
      }

      @Override
      public MsgPackSerializerSession build() {
         return new MsgPackSerializerSession(this);
      }

      @Override /* Overridden from Builder */
      public Builder debug(Boolean value) {
         super.debug(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder javaMethod(Method value) {
         super.javaMethod(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder locale(Locale value) {
         super.locale(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder mediaType(MediaType value) {
         super.mediaType(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder mediaTypeDefault(MediaType value) {
         super.mediaTypeDefault(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder properties(Map<String,Object> value) {
         super.properties(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder property(String key, Object value) {
         super.property(key, value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder resolver(VarResolverSession value) {
         super.resolver(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder schema(HttpPartSchema value) {
         super.schema(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder schemaDefault(HttpPartSchema value) {
         super.schemaDefault(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder timeZone(TimeZone value) {
         super.timeZone(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder timeZoneDefault(TimeZone value) {
         super.timeZoneDefault(value);
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder unmodifiable() {
         super.unmodifiable();
         return this;
      }

      @Override /* Overridden from Builder */
      public Builder uriContext(UriContext value) {
         super.uriContext(value);
         return this;
      }
   }

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

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

   /**
    * Creates a new builder for this object.
    *
    * @param ctx The context creating this session.
    *    <br>Cannot be <jk>null</jk>.
    * @return A new builder.
    */
   public static Builder create(MsgPackSerializer ctx) {
      return new Builder(assertArgNotNull("ctx", ctx));
   }

   /*
    * Converts the specified output target object to an {@link MsgPackOutputStream}.
    */
   private static MsgPackOutputStream getMsgPackOutputStream(SerializerPipe out) throws IOException {
      Object output = out.getRawOutput();
      if (output instanceof MsgPackOutputStream output2)
         return output2;
      var os = new MsgPackOutputStream(out.getOutputStream());
      out.setOutputStream(os);
      return os;
   }

   private final MsgPackSerializer ctx;

   /**
    * Constructor.
    *
    * @param builder The builder for this object.
    */
   protected MsgPackSerializerSession(Builder builder) {
      super(builder);
      ctx = builder.ctx;
   }

   /*
    * 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 SerializeException {

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

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

      var aType = (ClassMeta<?>)null;        // The actual type
      var sType = (ClassMeta<?>)null;        // The serialized type

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

      // Handle recursion
      if (aType == null)
         return out.appendNull();

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

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

      // Swap if necessary
      var swap = aType.getSwap(this);
      if (nn(swap)) {
         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() || (nn(pMeta) && 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.isByteArray()) {
         out.appendBinary((byte[])o);
      } else if (sType.isArray()) {
         serializeCollection(out, toList(sType.inner(), o), eType);
      } else if (sType.isReader()) {
         pipe((Reader)o, out, SerializerSession::handleThrown);
      } else if (sType.isInputStream()) {
         pipe((InputStream)o, out, SerializerSession::handleThrown);
      } else
         out.appendString(toString(o));

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

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

      Predicate<Object> checkNull = x -> isKeepNullProperties() || nn(x);

      var values = new ArrayList<BeanPropertyValue>();

      if (nn(typeName)) {
         BeanPropertyMeta pm = m.getMeta().getTypeProperty();
         values.add(new BeanPropertyValue(pm, pm.getName(), typeName, null));
      }

      m.forEachValue(checkNull, (pMeta, key, value, thrown) -> {
         if (nn(thrown)) {
            onBeanGetterException(pMeta, thrown);
            return;
         }
         var p = new BeanPropertyValue(pMeta, key, value, null);

         if ((! isKeepNullProperties()) && willRecurse(p)) {
            return; // Must handle the case where recursion occurs and property is not serialized.
         }

         values.add(p);
      });

      out.startMap(values.size());

      values.forEach(x -> {
         BeanPropertyMeta pMeta = x.getMeta();
         if (pMeta.canRead()) {
            var cMeta = x.getClassMeta();
            String key = x.getName();
            Object value = x.getValue();
            serializeAnything(out, key, null, null, null);
            serializeAnything(out, value, cMeta, key, pMeta);
         }
      });
   }

   @SuppressWarnings({ "rawtypes", "unchecked" })
   private void serializeCollection(MsgPackOutputStream out, Collection c, ClassMeta<?> type) throws SerializeException {
      var elementType = type.getElementType();
      List<Object> l = listOfSize(c.size());
      c = sort(c);
      l.addAll(c);
      out.startArray(l.size());
      l.forEach(x -> serializeAnything(out, x, elementType, "<iterator>", null));
   }

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

      var keyType = type.getKeyType();
      var 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 = listOfSize(m.size());
      m.forEach((k, v) -> entries.add(new SimpleMapEntry(k, v)));

      out.startMap(entries.size());

      entries.forEach(x -> {
         Object value = x.value;
         Object key = generalize(x.key, keyType);
         serializeAnything(out, key, keyType, null, null);
         serializeAnything(out, value, valueType, null, null);
      });
   }

   private boolean willRecurse(BeanPropertyValue v) throws SerializeException {
      var aType = push2(v.getName(), v.getValue(), v.getClassMeta());
      if (nn(aType))
         pop();
      return aType == null;
   }

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

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