using System;
using System.Collections.Generic;
using System.Text;

namespace DirectUSB.VirtualPackets
{
  public class VariableRequestPacket : VirtualPacket
  {
    #region Constructors / Teardown

    public VariableRequestPacket(string variableName, List<Attributes.Attribute.AttributeType> requestedAttributes,
      List<Attributes.SpecifiedAttribute> specifiedAttributes)
      : base(0x000C)
    {
      int specifiedAttributesSize = 0;
      foreach (var attrib in specifiedAttributes)
        specifiedAttributesSize += attrib.Data.Length;
      int totalSize = 2 + variableName.Length + 6 + 2 + (requestedAttributes.Count * 2) + 2 +
        (specifiedAttributes.Count * 4) + (specifiedAttributesSize);
      var data = new byte[totalSize];
      int index = 2;

      data[0] = (byte)((variableName.Length >> 8) & 0xFF);
      data[1] = (byte)(variableName.Length & 0xFF);
      for (int i = 0; i < variableName.Length; i++)
        data[index + i] = (byte)variableName[i];
      index += variableName.Length;

      data[index + 0] = 0x00;
      data[index + 1] = 0x01;
      data[index + 2] = 0xFF;
      data[index + 3] = 0xFF;
      data[index + 4] = 0xFF;
      data[index + 5] = 0xFF;
      index += 6;

      data[index + 0] = (byte)(requestedAttributes.Count >> 8);
      data[index + 1] = (byte)(requestedAttributes.Count & 0xFF);
      index += 2;
      for (int i = 0; i < requestedAttributes.Count; i++)
      {
        data[index + 0] = (byte)((short)requestedAttributes[i] >> 8);
        data[index + 1] = (byte)((short)requestedAttributes[i] & 0xFF);
        index += 2;
      }

      data[index + 0] = (byte)(specifiedAttributes.Count >> 8);
      data[index + 1] = (byte)(specifiedAttributes.Count & 0xFF);
      index += 2;
      for (int i = 0; i < specifiedAttributes.Count; i++)
      {
        data[index + 0] = (byte)((short)specifiedAttributes[i].Type >> 8);
        data[index + 1] = (byte)((short)specifiedAttributes[i].Type & 0xFF);
        data[index + 2] = (byte)((short)specifiedAttributes[i].Data.Length >> 8);
        data[index + 3] = (byte)((short)specifiedAttributes[i].Data.Length & 0xFF);
        for (int j = 0; j < specifiedAttributes[i].Data.Length; j++)
          data[index + 4 + j] = specifiedAttributes[i].Data[j];
        index += 4 + specifiedAttributes[i].Data.Length;
      }

      Data = data;
    }

    #endregion
  }
}