#region Copyright notice and license

// Copyright 2015, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#endregion

using System;
using Grpc.Core.Utils;

namespace Grpc.Core
{
    /// <summary>
    /// Encapsulates the logic for serializing and deserializing messages.
    /// </summary>
    public class Marshaller<T>
    {
        readonly Func<T, byte[]> serializer;
        readonly Func<byte[], T> deserializer;

        /// <summary>
        /// Initializes a new marshaller.
        /// </summary>
        /// <param name="serializer">Function that will be used to serialize messages.</param>
        /// <param name="deserializer">Function that will be used to deserialize messages.</param>
        public Marshaller(Func<T, byte[]> serializer, Func<byte[], T> deserializer)
        {
            this.serializer = Preconditions.CheckNotNull(serializer, "serializer");
            this.deserializer = Preconditions.CheckNotNull(deserializer, "deserializer");
        }

        /// <summary>
        /// Gets the serializer function.
        /// </summary>
        public Func<T, byte[]> Serializer
        {
            get
            {
                return this.serializer;
            }
        }

        /// <summary>
        /// Gets the deserializer function.
        /// </summary>
        public Func<byte[], T> Deserializer
        {
            get
            {
                return this.deserializer;
            }
        }
    }

    /// <summary>
    /// Utilities for creating marshallers.
    /// </summary>
    public static class Marshallers
    {
        /// <summary>
        /// Creates a marshaller from specified serializer and deserializer.
        /// </summary>
        public static Marshaller<T> Create<T>(Func<T, byte[]> serializer, Func<byte[], T> deserializer)
        {
            return new Marshaller<T>(serializer, deserializer);
        }

        /// <summary>
        /// Returns a marshaller for <c>string</c> type. This is useful for testing.
        /// </summary>
        public static Marshaller<string> StringMarshaller
        {
            get
            {
                return new Marshaller<string>(System.Text.Encoding.UTF8.GetBytes,
                                              System.Text.Encoding.UTF8.GetString);
            }
        }
    }
}