using System;
using System.Text;

namespace GemCard
{
	/// <summary>
	/// This class represents a command APDU
	/// </summary>
	public	class	APDUCommand
	{
		/// <summary>
        /// Minimun size of an APDU command in bytes
		/// </summary>
		public const int APDU_MIN_LENGTH = 4;

        public byte Class;      /// Class byte
        public byte Ins;        /// Instruction byte
        public byte P1;         /// Parameter P1 byte
        public byte P2;         /// Parameter P2 byte
        public byte[] Data;     /// Data to send to the card if any, null if no data to send
        public byte Le;	        /// Number of data expected, 0 if none

		/// <summary>
		/// Constructor
		/// </summary>
		/// <param name="bCla">Class byte</param>
		/// <param name="bIns">Instruction byte</param>
		/// <param name="bP1">Parameter P1 byte</param>
		/// <param name="bP2">Parameter P2 byte</param>
		/// <param name="baData">Data to send to the card if any, null if no data to send</param>
		/// <param name="bLe">Number of data expected, 0 if none</param>
		public APDUCommand(byte bCla, byte bIns, byte bP1, byte bP2, byte[] baData, byte bLe)
		{
            this.Class = bCla;
            this.Ins = bIns;
            this.P1 = bP1;
            this.P2 = bP2;
            this.Data = baData;
            this.Le = bLe;
		}


		/// <summary>
		/// Update the current APDU with selected parameters
		/// </summary>
		/// <param name="apduParam">APDU parameters</param>
		public void Update(APDUParam apduParam)
		{
			if (apduParam.UseData)    Data = apduParam.Data;
			if (apduParam.UseLe)      Le   = apduParam.Le;
			if (apduParam.UseP1)      P1   = apduParam.P1;
			if (apduParam.UseP2)      P2   = apduParam.P2;
            if (apduParam.UseChannel) Class += apduParam.Channel;
        }

        /// <summary>
        /// Overrides the ToString method to format to a string the APDUCommand object
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            string strData = null;
            byte bLc = 0;
            byte bP3 = Le;    

            if (Data != null)
            {
                StringBuilder sData = new StringBuilder(Data.Length * 2);
                for (int nI = 0; nI < Data.Length; nI++)
                {
                    sData.AppendFormat("{0:X02}", Data[nI]);
                }

                strData = "Data=" + sData.ToString();
                bLc = (byte) Data.Length;
                bP3 = bLc;
            }
            
            //string strApdu = string.Format("Class={0:X02} Ins={1:X02} P1={2:X02} P2={3:X02} Le={4:X02} Lc={5:X02} ",
                //m_bCla, m_bIns, m_bP1, m_bP2, m_bLe, bLc);
            StringBuilder strApdu = new StringBuilder();

            strApdu.AppendFormat("Class={0:X02} Ins={1:X02} P1={2:X02} P2={3:X02} P3={4:X02} ",
                Class, Ins, P1, P2, bP3);

            if (Data != null)
            {
                strApdu.Append(strData);
            }

            return strApdu.ToString();
        }
    }
}