using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using ln.objects.catalog;

namespace ln.types.odb.ng
{
    public class Document : ODBEntity
    {
        public override ODBValue Identity => new ODBGuid(ID);

        private Dictionary<ODBEntity, ODBEntity> properties = new Dictionary<ODBEntity, ODBEntity>();

        public Document()
            :base(0x1001)
        {
            ID = Guid.NewGuid();
        }

		public Document(Guid id)
			:base(0x1001)
		{
			ID = id;
		}

		public Guid ID { get; }
        public DateTime StorageTimeStamp { get; set; }

        public Document(byte[] bytes)
            : this(bytes, 0, bytes.Length) 
            {}
        public Document(byte[] bytes,int offset,int length)
            :this(new Guid(bytes.Slice(offset, 16)))
        {
            int endOffset = offset + length;

            offset += 16;   // GUID (!!!) -> this(...)

            int nProps = BitConverter.ToInt32(bytes, offset);
            offset += 4;

            for (int n=0;n<nProps;n++)
            {
                ODBEntity propName = ODBEntity.Deserialize(bytes,ref offset);
                ODBEntity propValue = ODBEntity.Deserialize(bytes, ref offset);
                properties.Add(propName, propValue);
            }

            if (offset > endOffset)
                throw new FormatException("Document deserialization read behind end of buffer");
        }

        public ODBEntity this[ODBEntity propName]
        {
            get
            {
                if (properties.ContainsKey(propName))
                    return properties[propName];
                return ODBNull.Instance;
            }
            set
            {
                if (ODBNull.Instance.Equals(value))
                {
					if (properties.ContainsKey(propName))
                    	properties.Remove(propName);
                }
                else
                {
                    properties[propName] = value;
                }
            }
        }
        public ODBEntity this[string propName]
        {
            get => this[new ODBStringValue(propName)];
            set => this[new ODBStringValue(propName)] = value;
        }

        public IEnumerable<ODBEntity> Keys => properties.Keys;

        public bool Contains(string propName) => Contains(new ODBStringValue(propName));
        public bool Contains(ODBEntity propName)
        {
            return !ODBNull.Instance.Equals(this[propName]);
        }

		public override ODBEntity Clone()
		{
			Document clone = new Document(ID);
			clone.StorageTimeStamp = StorageTimeStamp;

			foreach (ODBEntity fieldName in properties.Keys)
			{
				clone[fieldName] = this[fieldName].Clone();
			}
			return clone;
		}

		public void CloneTo(Document target)
		{
			target.properties.Clear();
			target.StorageTimeStamp = StorageTimeStamp;
			foreach (ODBEntity fieldName in properties.Keys)
			{
				target[fieldName] = this[fieldName].Clone();
			}
		}

		public override byte[] GetStorageBytes()
        {
            MemoryStream stream = new MemoryStream();
            BinaryWriter writer = new BinaryWriter(stream);

            writer.Write(ID.ToByteArray());
            writer.Write(properties.Count);

            foreach (ODBEntity propName in properties.Keys)
            {
                ODBEntity propValue = properties[propName];
                propName.Write(writer);
                propValue.Write(writer);
            }

            return stream.ToArray();
        }

        public override string ToString()
        {
            return String.Format("[Document ID={0} {1}]", ID.ToString(),String.Join(" ",properties.Select(kv=> String.Format("{0}={1}",kv.Key,kv.Value))));
        }
        public override string ToTreeString(int indent)
        {
            indent += 2;
            StringBuilder stringBuilder = new StringBuilder();

            stringBuilder.AppendFormat("{0} Identity={1} Count={2}", GetType().Name, Identity, properties.Count);
            foreach (ODBValue key in properties.Keys)
            {
                stringBuilder.AppendLine();
                stringBuilder.AppendFormat("{0}{1,-32}: {2}", new String(' ', indent), key, properties[key].ToTreeString(indent));
            }

            return stringBuilder.ToString();
        }


        public override int GetHashCode()
        {
            return ID.GetHashCode();
        }
        public override bool Equals(object obj)
        {
            if (Equals(GetType(), obj.GetType()) && (obj is Document))
            {
                Document you = obj as Document;
                return ID.Equals(you.ID);
            }
            return false;
        }

        protected override int compare(ODBEntity e)
        {
            Document other = e as Document;
            ODBEntity[] keys = Keys.Union(other.Keys).ToArray();

            foreach (ODBEntity key in keys)
            {
                ODBEntity mine = this[key];
                ODBEntity yours = other[key];

                int c = mine.CompareTo(yours);

                if (c != 0)
                    return c;
            }
            return 0;
        }

        public override T As<T>() => (T)Mapper.Default.UnmapValue(typeof(T), this);

        static Document()
        {
            RegisterDeserializer(0x1001, (b,o,l) => new Document(b,o,l));
        }
    }
}