main Program

program main
   use mpi
   use pFIO
   use MAPL_ExceptionHandling
   use collective_demo_CLI
   use FakeExtDataMod_collective
   implicit none

   integer :: rank, npes, ierror, provided,required
   integer :: status, color, key
   class(AbstractServer),pointer :: server
   class(AbstractDirectoryService), pointer :: d_s => null()

   type (CommandLineOptions) :: options
   integer, parameter :: NO_COLOR     = 0
   integer, parameter :: SERVER_COLOR = 1
   integer, parameter :: CLIENT_COLOR = 2
   integer, parameter :: BOTH_COLOR   = 3

   integer :: comm
!$   integer :: num_threads
   type (FakeExtData), target :: extData

   required = MPI_THREAD_MULTIPLE
   call MPI_init_thread(required, provided, ierror)
   call MPI_Comm_rank(MPI_COMM_WORLD, rank, ierror)
   call MPI_Comm_size(MPI_COMM_WORLD, npes, ierror)

   call process_command_line(options, rc=status)

!! sanity check

!$   if(options%server_type == 'openmp') then
!$     if (required > provided) stop "provided thread is not enough for openmp"
!$     num_threads = 10
!$     call omp_set_num_threads(num_threads) 
!$   endif

   d_s => get_directory_service(options%server_type)

   color = split_color(options%server_type,options%npes_server)
   key = 0

   call MPI_Comm_split(MPI_COMM_WORLD, color, key, comm, ierror)

   if (color == SERVER_COLOR .or. color == BOTH_COLOR) then ! server
      
      server=>get_server(options%server_type,comm,d_s,'i_server')
      if (color == SERVER_COLOR) call server%start()

   endif

   if (color == CLIENT_COLOR .or. color == BOTH_COLOR) then ! client

      call extData%init(options, comm, d_s, 'i_server')
      call extData%run(step=1)
      call extData%run(step=2)
      call extData%finalize()
 
   end if

   call MPI_finalize(ierror)

contains

   function get_directory_service(stype) result(d_s)
      character(*),intent(in) :: stype
      class(AbstractDirectoryService),pointer :: d_s

      allocate(d_s, source=DirectoryService(MPI_COMM_WORLD))

      _UNUSED_DUMMY(stype)

   end function

   function split_color(stype,split_rank) result(color)
      character(*),intent(in) :: stype
      integer,intent(in) :: split_rank  
      integer :: color

      select case (stype)
      case ('openmp','mpi')
         if (rank < split_rank) then
            color = SERVER_COLOR
         else
            color = CLIENT_COLOR
         end if
      case ('simple')
         color = BOTH_COLOR
      case default
         stop "not known server type"
      end select 

   end function

   function get_server(stype, comm, d_s, port_name) result(server)
      character(*),intent(in) :: stype
      integer,intent(in) :: comm
      class (AbstractDirectoryService), target, intent(inout) :: d_s
      character(*), intent(in) :: port_name

      class(BaseServer), pointer :: server

      select case (stype)
      case('mpi')
         allocate(server,source=MpiServer(comm, port_name))
         call d_s%publish(PortInfo(port_name, server),server)
         call d_s%connect_to_client(port_name, server)
         print*,"using MpiServer"
      case('openmp')
!C$        allocate(server,source=OpenmpServer(comm,d_s))
!C$        print*,"using OpenMpServer"
      case('simple')
         allocate(server,source=MpiServer(comm, port_name))
         call d_s%publish(PortInfo(port_name, server), server)
!C         call d_s%connect_to_client(port_name, server)
         print*,"using simple server"
      end select

     

    end function

end program main