#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2019 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.Reflection;
using HeuristicLab.Persistence.Core;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;
using HeuristicLab.Persistence.Interfaces;

namespace HeuristicLab.Persistence.Default.CompositeSerializers {

  [StorableClass]
  internal sealed class StructSerializer : ICompositeSerializer {

    [StorableConstructor]
    private StructSerializer(bool deserializing) { }
    public StructSerializer() { }

    public int Priority {
      get { return 50; }
    }

    public bool CanSerialize(Type type) {
      return type.IsValueType && !type.IsPrimitive && !type.IsEnum && type.IsSealed;
    }

    public string JustifyRejection(Type type) {
      if (!type.IsValueType)
        return "not a value type";
      if (type.IsPrimitive)
        return "type is primitive (int, float, ...)";
      if (type.IsEnum)
        return "type is enum";
      return "type is not sealed";
    }

    public IEnumerable<Tag> CreateMetaInfo(object obj) {
      return null;
    }

    private readonly BindingFlags AllInstanceMembers =
      BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;

    public IEnumerable<Tag> Decompose(object obj) {
      Type t = obj.GetType();
      foreach (MemberInfo mi in t.GetMembers(AllInstanceMembers)) {
        if (mi.MemberType == MemberTypes.Field) {
          string name = mi.Name.Replace("<", "&lt;").Replace(">", "&gt;");
          yield return new Tag(name, ((FieldInfo)mi).GetValue(obj));
        }
      }
    }

    public object CreateInstance(Type type, IEnumerable<Tag> metaInfo) {
      return Activator.CreateInstance(type, true);
    }

    public void Populate(object instance, IEnumerable<Tag> tags, Type type) {
      foreach (Tag t in tags) {
        string name = t.Name.Replace("&lt;", "<").Replace("&gt;", ">");
        MemberInfo[] mis = type.GetMember(name, AllInstanceMembers);
        if (mis.Length != 1)
          throw new PersistenceException("ambiguous struct member name " + name);
        MemberInfo mi = mis[0];
        if (mi.MemberType == MemberTypes.Field)
          ((FieldInfo)mi).SetValue(instance, t.Value);
        else
          throw new PersistenceException("invalid struct member type " + mi.MemberType.ToString());
      }
    }

  }
}