// /**
//  * File: ASN1Value.cs
//  * Author: haraldwolff
//  *
//  * This file and it's content is copyrighted by the Author and / or copyright holder.
//  * Any use wihtout proper permission is illegal and may lead to legal actions.
//  *
//  *
//  **/
using System;
using System.Collections.Generic;
using System.IO;
using ln.snmp.types;
using ln.logging;
namespace ln.snmp.asn1
{
    public class ASN1Value
    {
        public Identifier Identifier { get; set; }

        private byte[] octets;
        private List<ASN1Value> items;

        public ASN1Value(byte[] source)
            :this(new MemoryStream(source))
        {
        }
        public ASN1Value(Stream stream)
        {
            Identifier = BasicEncodingRules.ReadIdentifier(stream);
            int length = BasicEncodingRules.ReadLength(stream);

            if (Identifier.Constructed)
            {
                items = new List<ASN1Value>();

                long next = stream.Position + length;
                while (stream.Position < next)
                    items.Add(new ASN1Value(stream));
            }
            else
            {
                octets = new byte[length];
                stream.Read(octets, 0, length);
            }
        }

        public ASN1Value(Identifier identifier)
        {
            Identifier = identifier;
            if (Identifier.Constructed)
                items = new List<ASN1Value>();
            else
                octets = new byte[0];
        }

        public byte[] AsByteArray
        {
            get
            {
                if (Identifier.Constructed)
                {
                    byte[][] binaryItems = new byte[items.Count][];
                    int length = 0;
                    for (int n = 0; n < binaryItems.Length; n++)
                    {
                        binaryItems[n] = items[n].AsByteArray;
                        length += binaryItems[n].Length;
                    }

                    MemoryStream stream = new MemoryStream();
                    BasicEncodingRules.WriteIdentifier(stream, Identifier);
                    BasicEncodingRules.WriteLength(stream, length);
                    for (int n = 0; n < binaryItems.Length; n++)
                        stream.Write(binaryItems[n], 0, binaryItems[n].Length);

                    return stream.ToArray();
                }
                else
                {
                    MemoryStream stream = new MemoryStream();
                    BasicEncodingRules.WriteIdentifier(stream, Identifier);
                    BasicEncodingRules.WriteLength(stream, octets.Length);
                    stream.Write(octets, 0, octets.Length);
                    return stream.ToArray();
                }
            }
        }


        public byte[] Bytes
        {
            get
            {
                if (!Identifier.Constructed)
                {
                    return octets;
                }
                else
                {
                    byte[][] binaryItems = new byte[items.Count][];
                    int length = 0;
                    for (int n = 0; n < binaryItems.Length; n++)
                    {
                        binaryItems[n] = items[n].AsByteArray;
                        length += binaryItems[n].Length;
                    }

                    byte[] bytes = new byte[length];
                    int offset = 0;

                    for (int n = 0; n < binaryItems.Length; n++)
                    {
                        Array.Copy(binaryItems[n], 0, bytes, offset, binaryItems[n].Length);
                        offset += binaryItems[n].Length;
                    }

                    return bytes;
                }
            }
            set
            {
                if (!Identifier.Constructed)
                {
                    octets = value;
                }
                else
                {
                    throw new NotImplementedException();
                }
            }

        }

        public ASN1Value[] Items
        {
            get
            {
                if (!Identifier.Constructed)
                    throw new ArgumentOutOfRangeException("ASN1Value is not constructed");

                return items.ToArray();
            }
            set
            {
                if (!Identifier.Constructed)
                    throw new ArgumentOutOfRangeException("ASN1Value is not constructed");

                items = new List<ASN1Value>(value);
            }
        }

        public void Add(ASN1Value item)
        {
            if (!Identifier.Constructed)
                throw new ArgumentOutOfRangeException("ASN1Value is not constructed");
            items.Add(item);
        }

        public override string ToString()
        {
            return String.Format("[ASN1Value Identifier={0}]",Identifier);
        }

        public void Dump()
        {
            Dump("");
        }
        public void Dump(string prefix)
        {
            if (Identifier.Constructed)
            {
                Logging.Log(LogLevel.DEBUG, "{1}{0}", this.Identifier, prefix);
                foreach (ASN1Value item in items)
                    item.Dump(prefix + "    ");
            }
            else
            {
                Logging.Log(LogLevel.DEBUG, "{2}{0} {1}",this.Identifier,BitConverter.ToString(Bytes),prefix);
            }
        }


    }
}