using System;
using System.Collections;
using System.Text;
using System.Threading;
using sscs.verbs;
using sscs.common;
using sscs.cache;
using sscs.constants;

namespace sscs.verbs 
{
    
   /*
    * This class is implementation of RemoveSecret call.
    * There will be one instance existing for every call made by the client.  
    */

    internal class RemoveSecret : SSVerb
    {
        private ushort msgId = 0;
        private uint inMsgLen  = 0;
        private uint outMsgLen = 0;
        private uint keyChainIdLen = 0;
        private uint secretIdLen = 0;
        private int retCode = 0;
        private string keyChainId;
        private string secretId;
        
        private byte[] inBuf;
        private byte[] outBuf;
        /*
        * This method sets the class member with the byte array received.
        */
 
        public void SetMessageContent(byte[] ipcBytes)
        {
            CSSSLogger.ExecutionTrace(this);       
            inBuf = ipcBytes;                   
        }

       /*
        * This method does the actual implementation of RemoveSecret 
        *   
        */

        public byte[] ProcessRequest(UserIdentifier userId)
        {

            CSSSLogger.ExecutionTrace(this);
            /* If an exception occurs in message format decoding,
             * it is handled by AppHandler
             */

            // Message Format decipher - Start
            msgId          = BitConverter.ToUInt16(inBuf,0);
            inMsgLen       = BitConverter.ToUInt32(inBuf,2);
            if( inMsgLen != inBuf.Length )
                throw new FormatException(" MsgLen sent does not match the length of the message received.");


            keyChainIdLen  = BitConverter.ToUInt32(inBuf,6);

            byte[] keyChainIdArr = new byte[keyChainIdLen];
            Array.Copy(inBuf,10,keyChainIdArr,0,keyChainIdLen);
            keyChainId     = Encoding.UTF8.GetString(keyChainIdArr);

            secretIdLen    = BitConverter.ToUInt32(inBuf,
                             (10 + (int)keyChainIdLen));

            byte[] secretIdArr = new byte[secretIdLen];
            Array.Copy(inBuf,(10+keyChainIdLen+4),secretIdArr,0,secretIdLen);
            secretId = Encoding.UTF8.GetString(secretIdArr);
            // Message Format decipher - End

            try
            {
                SecretStore ssStore = SessionManager.GetUserSecretStore(userId);

                if( ssStore.CheckIfKeyChainExists(keyChainId) )
                {
                    KeyChain keyChain = ssStore.GetKeyChain(keyChainId);
                    if( keyChain.CheckIfSecretExists(secretId) == false)
                    {
                        retCode = IPCRetCodes.SSCS_E_SECRETID_DOES_NOT_EXIST;
                    }
                    else
                    {
						 // TODO: get the secret and remove linked keys
                         keyChain.RemoveSecret(secretId);
						 ssStore.UpdatePersistentStore();
                    }
                }
                else
                {
                    retCode = IPCRetCodes.SSCS_E_KEYCHAIN_DOES_NOT_EXIST;
                }
            }
            catch(UserNotInSessionException)
            {
                CSSSLogger.DbgLog("In " + CSSSLogger.GetExecutionPath(this) + " Unable to get user's secretstore" );
                retCode = IPCRetCodes.SSCS_E_SYSTEM_ERROR;
            }
            catch(Exception)
            {
                CSSSLogger.DbgLog( "In " + CSSSLogger.GetExecutionPath(this) + " - Secret ID not present" + secretId);
                retCode = IPCRetCodes.SSCS_E_SYSTEM_ERROR;
            }
                     
            // Construct a Reply

            try
            {
                msgId = 10;
                outMsgLen = 10;
                outBuf = new byte[outMsgLen];
                byte[] t = new byte[10];

                t = BitConverter.GetBytes((ushort)msgId);
                Array.Copy(t,0,outBuf,0,2);
  
                t = BitConverter.GetBytes((uint)outMsgLen);
                Array.Copy(t,0,outBuf,2,4);
 
                t = BitConverter.GetBytes(retCode);
                Array.Copy(t,0,outBuf,6,4);
            }
            catch(Exception e)
            {
                CSSSLogger.ExpLog(e.ToString());
                throw new FormatException("Unable to form the response " + e.ToString());
            }

            return outBuf;

        }


        /*
         * Gives the name of operation performed. Will be used in case 
         * of error. 
         */
        public string GetVerbName()
        {
            CSSSLogger.ExecutionTrace(this);
            return this.ToString(); 
        }
    }
}