using System;

namespace MyRM
{
  /// <summary>
  /// class MyRM implements: see TP.RM
  /// </summary>
 
public class MyRM : System.MarshalByRefObject, TP.RM
{
  MyLM lockManager;
   TP.TM transactionManager;
  System.Collections.Hashtable Items;
  System.Collections.Hashtable Reservations;
		
  /// <summary>
  ///Constructor
  /// </summary>
  public MyRM()
    {
     
     
      this.lockManager = new MyLM();
      /* don't need this for now */
      /*    this.transactionManager = (TP.TM) System.Activator.GetObject( typeof( MyTM.MyTM ), "http://localhost:8081/TM.soap");
      TP.Transaction tid = transactionManager.Start();
      transactionManager.Abort( tid );
      */
      
      Items = new System.Collections.Hashtable();
      Reservations = new System.Collections.Hashtable();
      
    }

  class Reservation
    {
      public TP.Customer Holder;
      public System.Collections.ArrayList Items;
      public Reservation( TP.Customer c, TP.Item i, int price )
	{
	  this.Holder = c;
	  Items = new System.Collections.ArrayList();
	  Items.Add( new ItemReservation( i, price ));
	}
    }

  class ItemReservation
    {
      public TP.Item ThisItem;
      public int Price;
      public ItemReservation( TP.Item i, int price)
	{
	  this.ThisItem=i;
	  Price = price;
	}
    }

  class  ItemInstance
    {
      string Name
	{
	  get
	    {
	      return i.Name;
	    }
	}
      TP.Item i;
      public int Count;
      public int CurrentPrice;
      public ItemInstance( TP.Item i, int count, int price )
	{
	  this.i = i;
	  this.Count = count;
	  this.CurrentPrice = price;
	}
    }

  static void Main( string [] args )
    {
      if (args.Length<1)
	{
	  Console.WriteLine("Usage: MyRM <rmName> [port_number]");
	  return;
	}
      string port_num;
      if (args.Length<2){
	port_num="8081";
      }
      else
	port_num=args[1];
      System.Console.WriteLine( string.Format( "Starting resource manager for {0} on port {1}", args[0],  port_num ));
      System.Threading.Thread.Sleep( 4000 ); // Wait for Transaction manager to come up
      System.Runtime.Remoting.Channels.Http.HttpChannel channel = new System.Runtime.Remoting.Channels.Http.HttpChannel( Convert.ToInt32(port_num) );
      System.Runtime.Remoting.Channels.ChannelServices.RegisterChannel( channel );
      System.Runtime.Remoting.RemotingConfiguration.RegisterWellKnownServiceType
	(		Type.GetType("MyRM.MyRM")				// assembly name
			,	"RM.soap"							//URI
			,	System.Runtime.Remoting.WellKnownObjectMode.Singleton	// instancing mode
			);
      while( true )
	System.Threading.Thread.Sleep( 100000 );

    }

  public void Enlist( TP.Transaction context )
    {
      // transactionManager.Enlist( context );
    }

  public void Commit(TP.Transaction context )
    {
      //transactionManager.Commit( context );
    }

  public void Abort(TP.Transaction context )
    {
      //transactionManager.Abort( context );
    }
    
  ///NEED TO ADD CODE
  ///This method adds a resource to the available ones
  public bool Add( TP.Transaction context, TP.Item i, int count, int price)
    {
      ItemInstance ii = (ItemInstance)Items[i.Name];
      if( ii != null )
	{
	  Console.WriteLine("RM: Add: item is null {0} ",i);
	  ii.Count += count;
	  ii.CurrentPrice = price;
	}
      else{
	Console.WriteLine("RM: Add: item is NOT null {0} ",i);
	Items.Add( i.Name, new ItemInstance( i, count, price ) );
				//NEED TO DO ADD LOCKING STUFF HERE

      }
      return true;
    }
  ///NEED TO ADD CODE
  public bool Delete( TP.Transaction context, TP.Item i )
    {
      //NEED TO DO ADD LOCKING STUFF HERE
      Items.Remove( i.Name );
      return true;
    }

		
  /// <summary>
  ///NEED TO ADD CODE For STEP 2
  /// The call to shutdown causes the RM to gracefully exit.
  /// It waits for all the existing txns to end and any new transaction
  /// enlistments are  refused. If any of the existing txns block
  /// forever, a retry/timeout mechanism is used to exit the RM
  /// no recovery is done upon startup
  /// </summary>
  public void Shutdown()
    {
    }

  /// <summary>
  // Call exit after a specified number of disk writes.
  /// Support for this method requires a wrapper around the system's
  /// write to disk command that decrements the counter set by this method.
  /// This counter should default to 0, which implies that the wrapper
  /// will do nothing.  If the count is non-zero, the wrapper should decrement
  /// the counter, see if it becomes zero, and if so, call exit(), otherwise
  /// continue the write.
  /// </summary>
  public void SelfDestruct(int diskWritesToWait)
    {
    }

   
  /// <summary>
  ///ADD CODE HERE
  /// returns the amount available for the specified item type
  /// </summary>
  public int Query( TP.Transaction context, TP.Item i )
    {
      Console.WriteLine("RM: Query");
      ItemInstance ii = (ItemInstance) Items[i.Name];
      if( ii == null )
	return 0;
      else
	return ii.Count;
    }

  /// <summary>
  ///ADD CODE HERE
  /// returns the price for the specified item type
  /// </summary>
  public int QueryPrice( TP.Transaction xId, TP.Item i )
    {
      return ((ItemInstance)Items[i.Name]).CurrentPrice;
    }

    
  /// <summary>
  ///ADD CODE HERE--need LOCKING: STEP 2
  ///Query the bill for a customer.
  ///</summary>
  /// <param name="context"></param>
  /// <param name="c">customer to be queried</param>
  /// <returns>Bill for customer</returns>
  public string QueryCustomerInfo( TP.Transaction context, TP.Customer c )
    {
      string order;
      order = "";
      Reservation r = (Reservation) Reservations[c.Id];
      foreach( ItemReservation rr in r.Items )
	{
	  if( order.Length > 0 )
	    order += ",";
	  order += rr.ThisItem.Name;
	}
      return order;
    }

  public int QueryCustomer( TP.Transaction context, TP.Customer c )
    {
      int bill=0;
      
      Reservation r = (Reservation) Reservations[c.Id];
      foreach( ItemReservation rr in r.Items )
	{
	   bill+= rr.Price;
	}
      return bill ;
    }
	
			
  /// <summary>
  ///ADD CODE HERE
  /// </summary>
  /// <param name="context"></param>
  /// <param name="c">Customer</param>
  /// <param name="i">item to reserve</param>
  /// <returns>success</returns>
  public bool Reserve( TP.Transaction context, TP.Customer c, TP.Item i )
    {
      ItemInstance ii = (ItemInstance)Items[i.Name];
      if( ii == null)
	throw new System.Exception( string.Format( "Item {0} does not exists", i.Name));
      if( ii.Count > 0 )
	{
	  Reservation r = (Reservation)Reservations[c.Id];
	  if( r == null ) 
	    {
	      r = new Reservation( c, i, ii.CurrentPrice );
	      Reservations.Add( c.Id, r );					
	    }
	  else{
	    r.Items.Add(new ItemReservation(i,ii.CurrentPrice));
	  }
	  ii.Count -= 1;
	  return true;
	}
      else
	throw new System.Exception( "No more items available" );
    }

  /// <summary>
  ///ADD CODE HERE
  /// </summary>
  /// <param name="context"></param>
  /// <param name="c">Customer</param>
  public void DropReservations( TP.Transaction context, TP.Customer c )
    {
      Reservation r = (Reservation) Reservations[c.Id];
      foreach( ItemReservation rr in r.Items )
	((ItemInstance)Items[rr.ThisItem]).Count += 1;
      Reservations.Remove(c.Id);
    }
}
}