#region CPL License
/*
Nuclex Framework
Copyright (C) 2002-2014 Nuclex Development Labs

This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.

You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion

using System;
using System.IO;
using System.Reflection;
using System.Runtime.Serialization;
using System.Runtime.Serialization.Formatters.Binary;

namespace Nuclex.Support.Cloning {

  /// <summary>Clones objects via serialization</summary>
  /// <remarks>
  ///   <para>
  ///     This type of cloning uses the binary formatter to persist the state of
  ///     an object and then restores it into a clone. It has the advantage of even
  ///     working with types that don't provide a default constructor, but is
  ///     terribly slow.
  ///   </para>
  ///   <para>
  ///     Inspired by the "A Generic Method for Deep Cloning in C# 3.0" article
  ///     on CodeProject: http://www.codeproject.com/KB/cs/generic_deep_cloning.aspx
  ///   </para>
  /// </remarks>
  public class SerializationCloner : ICloneFactory {

    #region class StaticSurrogateSelector

    /// <summary>Selects a static surrogate for any non-primitive types</summary>
    private class StaticSurrogateSelector : ISurrogateSelector {

      /// <summary>Initializes a new static surrogate selector</summary>
      /// <param name="staticSurrogate">Surrogate that will be selected</param>
      public StaticSurrogateSelector(ISerializationSurrogate staticSurrogate) {
        this.staticSurrogate = staticSurrogate;
      }

      /// <summary>
      ///   Sets the next selector to escalate to if this one can't provide a surrogate
      /// </summary>
      /// <param name="selector">Selector to escalate to</param>
      public void ChainSelector(ISurrogateSelector selector) {
        this.chainedSelector = selector;
      }

      /// <summary>
      ///   Returns the selector this one will escalate to if it can't provide a surrogate
      /// </summary>
      /// <returns>The selector this one will escalate to</returns>
      public ISurrogateSelector GetNextSelector() {
        return this.chainedSelector;
      }

      /// <summary>Attempts to provides a surrogate for the specified type</summary>
      /// <param name="type">Type a surrogate will be provided for</param>
      /// <param name="context">Context </param>
      /// <param name="selector"></param>
      /// <returns></returns>
      public ISerializationSurrogate GetSurrogate(
        Type type, StreamingContext context, out ISurrogateSelector selector
      ) {
        if(type.IsPrimitive || type.IsArray || (type == typeof(string))) {
          if(this.chainedSelector == null) {
            selector = null;
            return null;
          } else {
            return this.chainedSelector.GetSurrogate(type, context, out selector);
          }
        } else {
          selector = this;
          return this.staticSurrogate;
        }
      }

      /// <summary>Surrogate the that will be selected for any non-primitive types</summary>
      private readonly ISerializationSurrogate staticSurrogate;
      /// <summary>Surrogate selector to escalate to if no surrogate can be provided</summary>
      private ISurrogateSelector chainedSelector;

    }

    #endregion // class StaticSurrogateSelector

    #region class FieldSerializationSurrogate

    /// <summary>Serializes a type based on its fields</summary>
    private class FieldSerializationSurrogate : ISerializationSurrogate {

      /// <summary>Extracts the data to be serialized from an object</summary>
      /// <param name="objectToSerialize">Object that is being serialized</param>
      /// <param name="info">Stores the serialized informations</param>
      /// <param name="context">
      ///   Provides additional informations about the serialization process
      /// </param>
      public void GetObjectData(
        object objectToSerialize,
        SerializationInfo info,
        StreamingContext context
      ) {
        Type originalType = objectToSerialize.GetType();

        FieldInfo[] fieldInfos = originalType.GetFieldInfosIncludingBaseClasses(
          BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance
        );
        for(int index = 0; index < fieldInfos.Length; ++index) {
          FieldInfo fieldInfo = fieldInfos[index];
          info.AddValue(fieldInfo.Name, fieldInfo.GetValue(objectToSerialize));
        }
      }

      /// <summary>Reinserts saved data into a deserializd object</summary>
      /// <param name="deserializedObject">Object the saved data will be inserted into</param>
      /// <param name="info">Contains the serialized informations</param>
      /// <param name="context">
      ///   Provides additional informations about the serialization process
      /// </param>
      /// <param name="selector">Surrogate selector that specified this surrogate</param>
      /// <returns>The deserialized object</returns>
      public object SetObjectData(
        object deserializedObject,
        SerializationInfo info,
        StreamingContext context,
        ISurrogateSelector selector
      ) {
        Type originalType = deserializedObject.GetType();

        FieldInfo[] fieldInfos = originalType.GetFieldInfosIncludingBaseClasses(
          BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance
        );
        for(int index = 0; index < fieldInfos.Length; ++index) {
          FieldInfo fieldInfo = fieldInfos[index];
          fieldInfo.SetValue(deserializedObject, info.GetValue(fieldInfo.Name, fieldInfo.FieldType));
        }

        return deserializedObject;
      }

    }

    #endregion // class FieldSerializationSurrogate

    #region class PropertySerializationSurrogate

    /// <summary>Serializes a type based on its properties</summary>
    private class PropertySerializationSurrogate : ISerializationSurrogate {

      /// <summary>Extracts the data to be serialized from an object</summary>
      /// <param name="objectToSerialize">Object that is being serialized</param>
      /// <param name="info">Stores the serialized informations</param>
      /// <param name="context">
      ///   Provides additional informations about the serialization process
      /// </param>
      public void GetObjectData(
        object objectToSerialize,
        SerializationInfo info,
        StreamingContext context
      ) {
        Type originalType = objectToSerialize.GetType();

        PropertyInfo[] propertyInfos = originalType.GetProperties(
          BindingFlags.Public | BindingFlags.NonPublic |
          BindingFlags.Instance | BindingFlags.FlattenHierarchy
        );
        for(int index = 0; index < propertyInfos.Length; ++index) {
          PropertyInfo propertyInfo = propertyInfos[index];
          if(propertyInfo.CanRead && propertyInfo.CanWrite) {
            info.AddValue(propertyInfo.Name, propertyInfo.GetValue(objectToSerialize, null));
          }
        }
      }

      /// <summary>Reinserts saved data into a deserializd object</summary>
      /// <param name="deserializedObject">Object the saved data will be inserted into</param>
      /// <param name="info">Contains the serialized informations</param>
      /// <param name="context">
      ///   Provides additional informations about the serialization process
      /// </param>
      /// <param name="selector">Surrogate selector that specified this surrogate</param>
      /// <returns>The deserialized object</returns>
      public object SetObjectData(
        object deserializedObject,
        SerializationInfo info,
        StreamingContext context,
        ISurrogateSelector selector
      ) {
        Type originalType = deserializedObject.GetType();

        PropertyInfo[] propertyInfos = originalType.GetProperties(
          BindingFlags.Public | BindingFlags.NonPublic |
          BindingFlags.Instance | BindingFlags.FlattenHierarchy
        );
        for(int index = 0; index < propertyInfos.Length; ++index) {
          PropertyInfo propertyInfo = propertyInfos[index];
          if(propertyInfo.CanRead && propertyInfo.CanWrite) {
            propertyInfo.SetValue(
              deserializedObject,
              info.GetValue(propertyInfo.Name, propertyInfo.PropertyType),
              null
            );
          }
        }

        return deserializedObject;
      }

    }

    #endregion // class PropertySerializationSurrogate

    /// <summary>Initializes the static members of the serialization-based cloner</summary>
    static SerializationCloner() {
      fieldBasedFormatter = new BinaryFormatter(
        new StaticSurrogateSelector(new FieldSerializationSurrogate()),
        new StreamingContext(StreamingContextStates.All)
      );
      propertyBasedFormatter = new BinaryFormatter(
        new StaticSurrogateSelector(new PropertySerializationSurrogate()),
        new StreamingContext(StreamingContextStates.All)
      );
    }

    /// <summary>
    ///   Creates a deep clone of the specified object, also creating clones of all
    ///   child objects being referenced
    /// </summary>
    /// <typeparam name="TCloned">Type of the object that will be cloned</typeparam>
    /// <param name="objectToClone">Object that will be cloned</param>
    /// <returns>A deep clone of the provided object</returns>
    public static TCloned DeepFieldClone<TCloned>(TCloned objectToClone) {
      if(typeof(TCloned).IsClass || typeof(TCloned).IsArray) {
        if(ReferenceEquals(objectToClone, null)) {
          return default(TCloned);
        }
      }
      using(var memoryStream = new MemoryStream()) {
        fieldBasedFormatter.Serialize(memoryStream, objectToClone);
        memoryStream.Position = 0;
        return (TCloned)fieldBasedFormatter.Deserialize(memoryStream);
      }
    }

    /// <summary>
    ///   Creates a deep clone of the specified object, also creating clones of all
    ///   child objects being referenced
    /// </summary>
    /// <typeparam name="TCloned">Type of the object that will be cloned</typeparam>
    /// <param name="objectToClone">Object that will be cloned</param>
    /// <returns>A deep clone of the provided object</returns>
    public static TCloned DeepPropertyClone<TCloned>(TCloned objectToClone) {
      if(typeof(TCloned).IsClass || typeof(TCloned).IsArray) {
        if(ReferenceEquals(objectToClone, null)) {
          return default(TCloned);
        }
      }
      using(var memoryStream = new MemoryStream()) {
        propertyBasedFormatter.Serialize(memoryStream, objectToClone);
        memoryStream.Position = 0;
        return (TCloned)propertyBasedFormatter.Deserialize(memoryStream);
      }
    }

    /// <summary>
    ///   Creates a shallow clone of the specified object, reusing any referenced objects
    /// </summary>
    /// <typeparam name="TCloned">Type of the object that will be cloned</typeparam>
    /// <param name="objectToClone">Object that will be cloned</param>
    /// <returns>A shallow clone of the provided object</returns>
    TCloned ICloneFactory.ShallowFieldClone<TCloned>(TCloned objectToClone) {
      throw new NotSupportedException("The serialization cloner cannot create shallow clones");
    }

    /// <summary>
    ///   Creates a shallow clone of the specified object, reusing any referenced objects
    /// </summary>
    /// <typeparam name="TCloned">Type of the object that will be cloned</typeparam>
    /// <param name="objectToClone">Object that will be cloned</param>
    /// <returns>A shallow clone of the provided object</returns>
    TCloned ICloneFactory.ShallowPropertyClone<TCloned>(TCloned objectToClone) {
      throw new NotSupportedException("The serialization cloner cannot create shallow clones");
    }

    /// <summary>
    ///   Creates a deep clone of the specified object, also creating clones of all
    ///   child objects being referenced
    /// </summary>
    /// <typeparam name="TCloned">Type of the object that will be cloned</typeparam>
    /// <param name="objectToClone">Object that will be cloned</param>
    /// <returns>A deep clone of the provided object</returns>
    TCloned ICloneFactory.DeepFieldClone<TCloned>(TCloned objectToClone) {
      return SerializationCloner.DeepFieldClone<TCloned>(objectToClone);
    }

    /// <summary>
    ///   Creates a deep clone of the specified object, also creating clones of all
    ///   child objects being referenced
    /// </summary>
    /// <typeparam name="TCloned">Type of the object that will be cloned</typeparam>
    /// <param name="objectToClone">Object that will be cloned</param>
    /// <returns>A deep clone of the provided object</returns>
    TCloned ICloneFactory.DeepPropertyClone<TCloned>(TCloned objectToClone) {
      return SerializationCloner.DeepPropertyClone<TCloned>(objectToClone);
    }

    /// <summary>Serializes objects by storing their fields</summary>
    private static readonly BinaryFormatter fieldBasedFormatter;
    /// <summary>Serializes objects by storing their properties</summary>
    private static readonly BinaryFormatter propertyBasedFormatter;

  }

} // namespace Nuclex.Support.Cloning