/*
 * 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.
 */

using System.IO;
using Apache.Qpid.Proton.Buffer;

namespace Apache.Qpid.Proton.Codec.Decoders.Primitives
{
   /// <summary>
   /// Base map type decoder used by decoders of various AMQP types that represent
   /// map style serialized objects.
   /// </summary>
   public abstract class AbstractStringTypeDecoder : AbstractPrimitiveTypeDecoder, IStringTypeDecoder
   {
      public override object ReadValue(IProtonBuffer buffer, IDecoderState state)
      {
         int length = ReadSize(buffer, state);

         if (length > buffer.ReadableBytes || length < 0)
         {
            throw new DecodeException(string.Format(
                  "String encoded size {0} is specified to be greater than the amount " +
                  "of data available ({1})", (uint) length, buffer.ReadableBytes));
         }

         if (length != 0)
         {
            return state.DecodeUtf8(buffer, length);
         }
         else
         {
            return "";
         }
      }

      public override object ReadValue(Stream stream, IStreamDecoderState state)
      {
         int length = ReadSize(stream, state);

         if (length > state.MaxStringSize || length < 0)
         {
            throw new DecodeException(string.Format(
                  "String encoded size {0} is specified to be greater than the amount " +
                  "allowed by configuration ({1})", (uint) length, state.MaxStringSize));
         }

         if (length != 0)
         {
            return state.DecodeUtf8(stream, length);
         }
         else
         {
            return "";
         }
      }

      public override void SkipValue(IProtonBuffer buffer, IDecoderState state)
      {
         int length = ReadSize(buffer, state);

         if (length > buffer.ReadableBytes || length < 0)
         {
            throw new DecodeException(string.Format(
                  "String encoded size {0} is specified to be greater than the amount " +
                  "of data available ({1})", (uint) length, buffer.ReadableBytes));
         }

         buffer.SkipBytes(length);
      }

      public override void SkipValue(Stream stream, IStreamDecoderState state)
      {
         int length = ReadSize(stream, state);

         if (length > state.MaxStringSize || length < 0)
         {
            throw new DecodeException(string.Format(
                  "String encoded size {0} is specified to be greater than the amount " +
                  "allowed by configuration ({1})", (uint) length, state.MaxStringSize));
         }

         ProtonStreamReadUtils.SkipBytes(stream, length);
      }

      protected abstract int ReadSize(IProtonBuffer buffer, IDecoderState state);

      protected abstract int ReadSize(Stream stream, IStreamDecoderState state);

   }
}