#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2011 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using HeuristicLab.Persistence.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable.Descriptors;
using HeuristicLab.Persistence.Interfaces;

namespace HeuristicLab.Persistence.Default.CompositeSerializers.Storable {

  /// <summary>
  /// Intended for serialization of all custom classes. Classes should have the
  /// <c>[StorableClass]</c> attribute set. The default mode is to serialize
  /// members with the <c>[Storable]</c> attribute set. Alternatively the
  /// storable mode can be set to <c>AllFields</c>, <c>AllProperties</c>
  /// or <c>AllFieldsAndAllProperties</c>.
  /// </summary>
  [StorableClass]
  public sealed class StorableSerializer : ICompositeSerializer {

    public StorableSerializer() { }

    [StorableConstructor]
    private StorableSerializer(bool deserializing) : this() { }

    #region ICompositeSerializer implementation

    /// <summary>
    /// Priority 200, one of the first default composite serializers to try.
    /// </summary>
    /// <value></value>
    public int Priority {
      get { return 200; }
    }

    /// <summary>
    /// Determines for every type whether the composite serializer is applicable.
    /// </summary>
    /// <param name="type">The type.</param>
    /// <returns>
    /// 	<c>true</c> if this instance can serialize the specified type; otherwise, <c>false</c>.
    /// </returns>
    public bool CanSerialize(Type type) {
      TypeDescriptor desc = StorableClassAnalyzer.GetDescriptor(type);
      if (desc.IsInvalid)
        return false;
      if (desc.HasDefaultConstructor)
        return true;
      else if (desc.IsStorableClass)
        if (desc.HasDefaultConstructor || desc.HasStorableConstructor)
          return true;
        else
          throw new PersistenceException("[Storable] type has no default constructor and no [StorableConstructor]");
      return false;
    }

    /// <summary>
    /// Give a reason if possibly why the given type cannot be serialized by this
    /// ICompositeSerializer.
    /// </summary>
    /// <param name="type">The type.</param>
    /// <returns>
    /// A string justifying why type cannot be serialized.
    /// </returns>
    public string JustifyRejection(Type type) {
      StringBuilder sb = new StringBuilder();
      TypeDescriptor desc = StorableClassAnalyzer.GetDescriptor(type);
      if (desc.IsInvalid)
        sb.Append("class is not marked [StorableClass] but has mutable members.");
      if (!desc.IsStorableClass)
        sb.Append("class is not marked [StorableClass]");
      if (!desc.HasDefaultConstructor)
        sb.Append("class has no default constructor");
      if (!desc.HasStorableConstructor)
        sb.Append("class has no [StorableConstructor]");
      return sb.ToString();
    }

    /// <summary>
    /// Creates the meta info.
    /// </summary>
    /// <param name="o">The object.</param>
    /// <returns>A list of storable components.</returns>
    public IEnumerable<Tag> CreateMetaInfo(object o) {
      return new Tag[] { };
    }

    /// <summary>
    /// Decompose an object into <see cref="Tag"/>s, the tag name can be null,
    /// the order in which elements are generated is guaranteed to be
    /// the same as they will be supplied to the Populate method.
    /// </summary>
    /// <param name="obj">An object.</param>
    /// <returns>An enumerable of <see cref="Tag"/>s.</returns>
    public IEnumerable<Tag> Decompose(object obj) {
      foreach (var kvp in StorableClassAnalyzer.GetDescriptor(obj.GetType()).Decompose(obj)) {
        yield return new Tag(kvp.Key, kvp.Value);
      }
    }

    /// <summary>
    /// Create an instance of the object using the provided meta information.
    /// </summary>
    /// <param name="type">A type.</param>
    /// <param name="metaInfo">The meta information.</param>
    /// <returns>A fresh instance of the provided type.</returns>
    public object CreateInstance(Type type, IEnumerable<Tag> metaInfo) {
      try {
        return StorableClassAnalyzer.GetDescriptor(type).CreateInstance();
      } catch (TargetInvocationException x) {
        throw new PersistenceException(
          "Could not instantiate storable object: Encountered exception during constructor call",
          x.InnerException);
      }
    }

    /// <summary>
    /// Populates the specified instance.
    /// </summary>
    /// <param name="instance">The instance.</param>
    /// <param name="objects">The objects.</param>
    /// <param name="type">The type.</param>
    public void Populate(object instance, IEnumerable<Tag> objects, Type type) {
      StorableClassAnalyzer.GetDescriptor(type).Populate(instance, objects.ToDictionary(kvp => kvp.Name, kvp => kvp.Value));
    }

    #endregion

  }

}