#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 Google.Protobuf;

namespace HeuristicLab.Persistence {
  public sealed class Mapper {
    internal class MappingEqualityComparer : IEqualityComparer<object> {
      bool IEqualityComparer<object>.Equals(object x, object y) {
        if (x == null && y == null) return true;
        if (x == null ^ y == null) return false;
        if (x.GetType() != y.GetType()) return false;

        var type = x.GetType();
        if (type.IsValueType || type == typeof(string)) return x.Equals(y);
        return object.ReferenceEquals(x, y);
      }

      int IEqualityComparer<object>.GetHashCode(object obj) {
        return obj == null ? 0 : obj.GetHashCode();
      }
    }

    private static StaticCache staticCache;
    private static object locker = new object();
    public static StaticCache StaticCache {
      get {
        lock (locker) {
          if (staticCache == null) staticCache = new StaticCache();
          return staticCache;
        }
      }
    }

    private Index<ITransformer> transformers;
    private Index<Type> types;

    private Dictionary<uint, Box> boxId2Box;
    private Dictionary<object, uint> object2BoxId;
    private Dictionary<uint, object> boxId2Object;
    private Index<TypeBox> typeBoxes;

    private Index<string> strings;

    private Index<BoolArrayBox> boolArrayBoxes;
    private Index<IntArrayBox> intArrayBoxes;
    private Index<UnsignedIntArrayBox> unsignedIntArrayBoxes;
    private Index<LongArrayBox> longArrayBoxes;
    private Index<UnsignedLongArrayBox> unsignedLongArrayBoxes;
    private Index<FloatArrayBox> floatArrayBoxes;
    private Index<DoubleArrayBox> doubleArrayBoxes;

    private Index<DictionaryBox> dictionaryBoxes;
    private Index<StorableClassBox> storableClassBoxes;

    public uint BoxCount { get; private set; }


    public Mapper() {
      transformers = new Index<ITransformer>();
      types = new Index<Type>();

      boxId2Box = new Dictionary<uint, Box>();
      object2BoxId = new Dictionary<object, uint>(new MappingEqualityComparer());
      boxId2Object = new Dictionary<uint, object>();
      typeBoxes = new Index<TypeBox>();

      strings = new Index<string>();

      boolArrayBoxes = new Index<BoolArrayBox>();
      intArrayBoxes = new Index<IntArrayBox>();
      unsignedIntArrayBoxes = new Index<UnsignedIntArrayBox>();
      longArrayBoxes = new Index<LongArrayBox>();
      unsignedLongArrayBoxes = new Index<UnsignedLongArrayBox>();
      floatArrayBoxes = new Index<FloatArrayBox>();
      doubleArrayBoxes = new Index<DoubleArrayBox>();

      dictionaryBoxes = new Index<DictionaryBox>();
      storableClassBoxes = new Index<StorableClassBox>();

      BoxCount = 0;
    }

    #region Transformers
    public uint GetTransformerId(ITransformer transformer) {
      return transformers.GetIndex(transformer);
    }

    public ITransformer GetTransformer(uint transformerId) {
      return transformers.GetValue(transformerId);
    }
    #endregion

    #region Types
    public uint GetTypeId(Type type) {
      return types.GetIndex(type);
    }

    public Type GetType(uint typeId) {
      return types.GetValue(typeId);
    }
    #endregion

    #region Boxes
    public uint GetBoxId(object o) {
      uint boxId;

      if (o == null)
        boxId = 0;
      else {
        if (object2BoxId.TryGetValue(o, out boxId)) return boxId;
        var type = o.GetType();
        var typeInfo = StaticCache.GetTypeInfo(type);
        if (typeInfo.Transformer == null) throw new ArgumentException("Cannot serialize object of type " + o.GetType());
        boxId = ++BoxCount;
        typeInfo.Used++;
        object2BoxId.Add(o, boxId);
        boxId2Box.Add(boxId, typeInfo.Transformer.ToBox(o, this));
      }
      return boxId;
    }

    public Box GetBox(uint boxId) {
      return boxId2Box[boxId];
    }

    public object GetObject(uint boxId) {
      object o;
      if (boxId2Object.TryGetValue(boxId, out o)) return o;

      Box box;
      boxId2Box.TryGetValue(boxId, out box);

      if (box == null)
        o = null;
      else {
        var transformer = transformers.GetValue(box.TransformerId);
        o = transformer.ToObject(box, this);
        boxId2Object.Add(boxId, o);
        transformer.FillFromBox(o, box, this);
      }

      return o;
    }

    #region Referenced Boxes
    #region TypeBoxes
    public uint GetTypeBoxId(TypeBox typeBox) { return typeBoxes.GetIndex(typeBox); }
    public TypeBox GetTypeBox(uint typeBoxId) { return typeBoxes.GetValue(typeBoxId); }
    #endregion

    #region BoolArrayBox
    public uint GetBoolArrayBoxId(BoolArrayBox boolArrayBox) { return boolArrayBoxes.GetIndex(boolArrayBox); }
    public BoolArrayBox GetBoolArrayBox(uint boolArrayBoxId) { return boolArrayBoxes.GetValue(boolArrayBoxId); }
    #endregion

    #region IntArrayBox
    public uint GetIntArrayBoxId(IntArrayBox intArrayBox) { return intArrayBoxes.GetIndex(intArrayBox); }
    public IntArrayBox GetIntArrayBox(uint intArrayBoxId) { return intArrayBoxes.GetValue(intArrayBoxId); }
    #endregion

    #region UnsignedIntArrayBox
    public uint GetUnsignedIntArrayBoxId(UnsignedIntArrayBox unsignedIntArrayBox) { return unsignedIntArrayBoxes.GetIndex(unsignedIntArrayBox); }
    public UnsignedIntArrayBox GetUnsignedIntArrayBox(uint unsignedIntArrayBoxId) { return unsignedIntArrayBoxes.GetValue(unsignedIntArrayBoxId); }
    #endregion

    #region LongArrayBox
    public uint GetLongArrayBoxId(LongArrayBox longArrayBox) { return longArrayBoxes.GetIndex(longArrayBox); }
    public LongArrayBox GetLongArrayBox(uint longArrayBoxId) { return longArrayBoxes.GetValue(longArrayBoxId); }
    #endregion

    #region UnsignedLongArrayBox
    public uint GetUnsignedLongArrayBoxId(UnsignedLongArrayBox unsignedLongArrayBox) { return unsignedLongArrayBoxes.GetIndex(unsignedLongArrayBox); }
    public UnsignedLongArrayBox GetUnsignedLongArrayBox(uint unsignedLongArrayBoxId) { return unsignedLongArrayBoxes.GetValue(unsignedLongArrayBoxId); }
    #endregion

    #region FloatArrayBox
    public uint GetFloatArrayBoxId(FloatArrayBox floatArrayBox) { return floatArrayBoxes.GetIndex(floatArrayBox); }
    public FloatArrayBox GetFloatArrayBox(uint floatArrayBoxId) { return floatArrayBoxes.GetValue(floatArrayBoxId); }
    #endregion

    #region DoubleArrayBox
    public uint GetDoubleArrayBoxId(DoubleArrayBox doubleArrayBox) { return doubleArrayBoxes.GetIndex(doubleArrayBox); }
    public DoubleArrayBox GetDoubleArrayBox(uint doubleArrayBoxId) { return doubleArrayBoxes.GetValue(doubleArrayBoxId); }
    #endregion

    #region DictionaryBox
    public uint GetDictionaryBoxId(DictionaryBox dictionaryBox) { return dictionaryBoxes.GetIndex(dictionaryBox); }
    public DictionaryBox GetDictionaryBox(uint dictionaryBoxId) { return dictionaryBoxes.GetValue(dictionaryBoxId); }
    #endregion

    #region StorableClassBox
    public uint GetStorableClassBoxId(StorableClassBox storableClassBox) { return storableClassBoxes.GetIndex(storableClassBox); }
    public StorableClassBox GetStorableClassBox(uint storableClassBoxId) { return storableClassBoxes.GetValue(storableClassBoxId); }
    #endregion
    #endregion
    #endregion

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

    public object CreateInstance(Type type) {
      try {
        return StaticCache.GetTypeInfo(type).GetConstructor()();
      } catch (Exception e) {
        throw new PersistenceException("Deserialization failed.", e);
      }
    }

    public static Bundle ToBundle(object o) {
      var mapper = new Mapper();
      var bundle = new Bundle();

      bundle.RootBoxId = mapper.GetBoxId(o);
      bundle.TransformerGuids.AddRange(mapper.transformers.GetValues().Select(x => x.Guid).Select(x => ByteString.CopyFrom(x.ToByteArray())));
      bundle.TypeGuids.AddRange(mapper.types.GetValues().Select(x => ByteString.CopyFrom(StaticCache.GetGuid(x).ToByteArray())));
      bundle.Boxes.AddRange(mapper.boxId2Box.OrderBy(x => x.Key).Select(x => x.Value));
      bundle.TypeBoxes.AddRange(mapper.typeBoxes.GetValues());

      bundle.Strings.AddRange(mapper.strings.GetValues());

      bundle.BoolArrayBoxes.AddRange(mapper.boolArrayBoxes.GetValues());
      bundle.IntArrayBoxes.AddRange(mapper.intArrayBoxes.GetValues());
      bundle.UnsignedIntArrayBoxes.AddRange(mapper.unsignedIntArrayBoxes.GetValues());
      bundle.LongArrayBoxes.AddRange(mapper.longArrayBoxes.GetValues());
      bundle.UnsignedLongArrayBoxes.AddRange(mapper.unsignedLongArrayBoxes.GetValues());
      bundle.FloatArrayBoxes.AddRange(mapper.floatArrayBoxes.GetValues());
      bundle.DoubleArrayBoxes.AddRange(mapper.doubleArrayBoxes.GetValues());

      bundle.DictionaryBoxes.AddRange(mapper.dictionaryBoxes.GetValues());
      bundle.StorableClassBoxes.AddRange(mapper.storableClassBoxes.GetValues());

      return bundle;
    }
    public static object ToObject(Bundle bundle) {
      var mapper = new Mapper();

      mapper.transformers = new Index<ITransformer>(bundle.TransformerGuids.Select(x => new Guid(x.ToByteArray())).Select(StaticCache.GetTransformer));
      mapper.types = new Index<Type>(bundle.TypeGuids.Select(x => StaticCache.GetType(new Guid(x.ToByteArray()))));

      mapper.boxId2Box = bundle.Boxes.Select((b, i) => new { Box = b, Index = i }).ToDictionary(k => (uint)k.Index + 1, v => v.Box);
      mapper.typeBoxes = new Index<TypeBox>(bundle.TypeBoxes);

      mapper.strings = new Index<string>(bundle.Strings);

      mapper.boolArrayBoxes = new Index<BoolArrayBox>(bundle.BoolArrayBoxes);
      mapper.intArrayBoxes = new Index<IntArrayBox>(bundle.IntArrayBoxes);
      mapper.unsignedIntArrayBoxes = new Index<UnsignedIntArrayBox>(bundle.UnsignedIntArrayBoxes);
      mapper.longArrayBoxes = new Index<LongArrayBox>(bundle.LongArrayBoxes);
      mapper.unsignedLongArrayBoxes = new Index<UnsignedLongArrayBox>(bundle.UnsignedLongArrayBoxes);
      mapper.floatArrayBoxes = new Index<FloatArrayBox>(bundle.FloatArrayBoxes);
      mapper.doubleArrayBoxes = new Index<DoubleArrayBox>(bundle.DoubleArrayBoxes);

      mapper.dictionaryBoxes = new Index<DictionaryBox>(bundle.DictionaryBoxes);
      mapper.storableClassBoxes = new Index<StorableClassBox>(bundle.StorableClassBoxes);

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