#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2015 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 HeuristicLab.PluginInfrastructure;
using Google.ProtocolBuffers;
using HeuristicLab.Persistence.Default.CompositeSerializers.Storable;

namespace HeuristicLab.Persistence {
  public sealed class Mapper {
    private Index<ITransformer> transformers;
    private Dictionary<Type, TypeInfo> typeInfos;
    private Index<Type> types;
    private Index<string> strings;
    private Index<Box> boxes;
    private Dictionary<object, uint> boxCache;
    private Dictionary<uint, object> objectCache;

    public long BoxCount { get; private set; }

    public Mapper() {
      transformers = new Index<ITransformer>();
      typeInfos = new Dictionary<Type, TypeInfo>();
      types = new Index<Type>();
      strings = new Index<string>();
      boxes = new Index<Box>();
      boxCache = new Dictionary<object, uint>(new ReferenceEqualityComparer<object>());
      objectCache = new Dictionary<uint, object>();

      BoxCount = 0;

      foreach (var transformer in ApplicationManager.Manager.GetInstances<ITransformer>().OrderBy(x => x.Order)) {
        transformer.Initialize(transformers.GetIndex(transformer));
      }
    }

    public TypeInfo GetTypeInfo(Type type) {
      TypeInfo typeInfo;
      if (!typeInfos.TryGetValue(type, out typeInfo)) {
        var transformer = transformers.GetValues().Where(x => x.CanTransformType(type)).FirstOrDefault();
        typeInfo = new TypeInfo(type, transformer);
        typeInfos.Add(type, typeInfo);
      }
      return typeInfo;
    }
    public IEnumerable<TypeInfo> GetTypeInfos() {
      return typeInfos.Values;
    }
    public IEnumerable<Type> GetTypes() {
      return typeInfos.Values.Select(x => x.Type);
    }

    public uint GetTypeId(Type type) {
      return types.GetIndex(type);
    }
    public Type GetType(uint typeId) {
      return types.GetValue(typeId);
    }

    public uint GetStringId(string str) {
      return strings.GetIndex(str);
    }
    public string GetString(uint stringId) {
      return strings.GetValue(stringId);
    }

    public uint GetBoxId(object o) {
      uint boxId;
      if (boxCache.TryGetValue(o, out boxId)) return boxId;

      if (o == null)
        boxId = boxes.GetIndex(null);
      else {
        var type = o.GetType();
        var typeInfo = GetTypeInfo(type);
        if (typeInfo.Transformer == null) throw new ArgumentException("Cannot serialize object of type " + o.GetType());
        BoxCount++;
        typeInfo.Used++;
        boxId = boxes.GetIndex(typeInfo.Transformer.ToBox(o, this));
      }
      boxCache.Add(o, boxId);
      return boxId;
    }
    public object GetObject(uint boxId) {
      object o;
      if (objectCache.TryGetValue(boxId, out o)) return o;

      var box = this.boxes.GetValue(boxId);
      if (box == null)
        o = null;
      else {
        var transformer = transformers.GetValue(box.TransformerId);
        o = transformer.ToObject(box, this);
      }
      objectCache.Add(boxId, o);
      return o;
    }

    public object CreateInstance(Type type) {
      return GetTypeInfo(type).GetConstructor()();
    }

    public static Bundle ToBundle(object o) {
      var mapper = new Mapper();
      var bundle = Bundle.CreateBuilder();
      bundle.RootBoxId = mapper.GetBoxId(o);
      bundle.AddRangeTransformerGuids(mapper.transformers.GetValues().Select(x => x.Guid).Select(x => ByteString.CopyFrom(x.ToByteArray())));
      bundle.AddRangeTypeGuids(mapper.types.GetValues().Select(x => mapper.typeInfos[x].StorableClassAttribute.Guid).Select(x => ByteString.CopyFrom(x.ToByteArray())));
      bundle.AddRangeStrings(mapper.strings.GetValues());
      bundle.AddRangeBoxes(mapper.boxes.GetValues());
      return bundle.Build();
    }
    public static object ToObject(Bundle bundle) {
      var types = new Dictionary<Guid, Type>();
      foreach (var asm in AppDomain.CurrentDomain.GetAssemblies()) {
        foreach (var t in asm.GetTypes().Where(x => StorableClassAttribute.IsStorableClass(x)))
          types.Add(StorableClassAttribute.GetStorableClassAttribute(t).Guid, t);
      }

      var mapper = new Mapper();
      mapper.types = new Index<Type>(bundle.TypeGuidsList.Select(x => new Guid(x.ToByteArray())).Select(x => types[x]));
      mapper.strings = new Index<string>(bundle.StringsList);
      mapper.boxes = new Index<Box>(bundle.BoxesList);
      mapper.transformers = new Index<ITransformer>(bundle.TransformerGuidsList.Select(x => new Guid(x.ToByteArray())).Select(x => mapper.transformers.GetValues().First(y => y.Guid == x)));
      foreach (var type in mapper.types.GetValues())
        mapper.typeInfos.Add(type, new TypeInfo(type));

      return mapper.GetObject(bundle.RootBoxId);
    }
  }
}