// Fig. 22.22: ReservationService.cs
// Airline reservation WCF web service.
using System.Linq;

public class ReservationService : IReservationService
{
   // create ticketsDB object to access Tickets database
   private TicketsDataContext ticketsDB = new TicketsDataContext();

   // checks database to determine whether matching seat is available
   public bool Reserve( string seatType, string classType )
   {
      //  LINQ query to find seats matching the parameters
      var result =
         from seat in ticketsDB.Seats
         where ( seat.Taken == false ) && ( seat.Type == seatType ) &&
            ( seat.Class == classType )
         select seat;

      // get first available seat
      Seat firstAvailableSeat = result.FirstOrDefault();

      // if seat is available seats, mark it as taken
      if ( firstAvailableSeat != null )
      {
         firstAvailableSeat.Taken = true; // mark the seat as taken
         ticketsDB.SubmitChanges(); // update 
         return true; // seat was reserved
      } // end if

      return false; // no seat was reserved
   } // end method Reserve
} // end class ReservationService

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