!   
!                Parallel Sparse BLAS  version 3.5
!      (C) Copyright 2006-2018
!        Salvatore Filippone    
!        Alfredo Buttari      
!   
!    Redistribution and use in source and binary forms, with or without
!    modification, are permitted provided that the following conditions
!    are met:
!      1. Redistributions of source code must retain the above copyright
!         notice, this list of conditions and the following disclaimer.
!      2. Redistributions in binary form must reproduce the above copyright
!         notice, this list of conditions, and the following disclaimer in the
!         documentation and/or other materials provided with the distribution.
!      3. The name of the PSBLAS group or the names of its contributors may
!         not be used to endorse or promote products derived from this
!         software without specific written permission.
!   
!    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
!    ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
!    TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
!    PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
!    BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
!    CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
!    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
!    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
!    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
!    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
!    POSSIBILITY OF SUCH DAMAGE.
!   
!    
#if defined(SERIAL_MPI)
! Provide a fake mpi module just to keep the compiler(s) happy.
module mpi
  use psb_const_mod
  integer(psb_mpk_), parameter :: mpi_success          = 0
  integer(psb_mpk_), parameter :: mpi_request_null     = 0
  integer(psb_mpk_), parameter :: mpi_status_size      = 1
  integer(psb_mpk_), parameter :: mpi_integer          = 1
  integer(psb_mpk_), parameter :: mpi_integer8         = 2
  integer(psb_mpk_), parameter :: mpi_real             = 3
  integer(psb_mpk_), parameter :: mpi_double_precision = 4
  integer(psb_mpk_), parameter :: mpi_complex          = 5   
  integer(psb_mpk_), parameter :: mpi_double_complex   = 6 
  integer(psb_mpk_), parameter :: mpi_character        = 7
  integer(psb_mpk_), parameter :: mpi_logical          = 8
  integer(psb_mpk_), parameter :: mpi_integer2         = 9
  integer(psb_mpk_), parameter :: mpi_comm_null        = -1
  integer(psb_mpk_), parameter :: mpi_comm_world       = 1
  
  real(psb_dpk_), external :: mpi_wtime
end module mpi
#endif    

module psi_comm_buffers_mod
  use psb_const_mod

  integer(psb_mpk_), parameter:: psb_int_tag      = 543987
  integer(psb_mpk_), parameter:: psb_real_tag     = psb_int_tag      + 1
  integer(psb_mpk_), parameter:: psb_double_tag   = psb_real_tag     + 1
  integer(psb_mpk_), parameter:: psb_complex_tag  = psb_double_tag   + 1
  integer(psb_mpk_), parameter:: psb_dcomplex_tag = psb_complex_tag  + 1
  integer(psb_mpk_), parameter:: psb_logical_tag  = psb_dcomplex_tag + 1
  integer(psb_mpk_), parameter:: psb_char_tag     = psb_logical_tag  + 1
  integer(psb_mpk_), parameter:: psb_int8_tag     = psb_char_tag     + 1
  integer(psb_mpk_), parameter:: psb_int2_tag     = psb_int8_tag     + 1
  integer(psb_mpk_), parameter:: psb_int4_tag     = psb_int2_tag     + 1
  integer(psb_mpk_), parameter:: psb_long_tag     = psb_int4_tag     + 1

  integer(psb_mpk_), parameter:: psb_int_swap_tag      = psb_int_tag      + psb_int_tag
  integer(psb_mpk_), parameter:: psb_real_swap_tag     = psb_real_tag     + psb_int_tag
  integer(psb_mpk_), parameter:: psb_double_swap_tag   = psb_double_tag   + psb_int_tag
  integer(psb_mpk_), parameter:: psb_complex_swap_tag  = psb_complex_tag  + psb_int_tag
  integer(psb_mpk_), parameter:: psb_dcomplex_swap_tag = psb_dcomplex_tag + psb_int_tag
  integer(psb_mpk_), parameter:: psb_logical_swap_tag  = psb_logical_tag  + psb_int_tag
  integer(psb_mpk_), parameter:: psb_char_swap_tag     = psb_char_tag     + psb_int_tag
  integer(psb_mpk_), parameter:: psb_int8_swap_tag     = psb_int8_tag     + psb_int_tag
  integer(psb_mpk_), parameter:: psb_int2_swap_tag     = psb_int2_tag     + psb_int_tag
  integer(psb_mpk_), parameter:: psb_int4_swap_tag     = psb_int4_tag     + psb_int_tag
  integer(psb_mpk_), parameter:: psb_long_swap_tag     = psb_long_tag     + psb_int_tag


  
  integer(psb_mpk_), private, parameter:: psb_int_type      = 987543
  integer(psb_mpk_), private, parameter:: psb_real_type     = psb_int_type      + 1
  integer(psb_mpk_), private, parameter:: psb_double_type   = psb_real_type     + 1
  integer(psb_mpk_), private, parameter:: psb_complex_type  = psb_double_type   + 1
  integer(psb_mpk_), private, parameter:: psb_dcomplex_type = psb_complex_type  + 1
  integer(psb_mpk_), private, parameter:: psb_logical_type  = psb_dcomplex_type + 1
  integer(psb_mpk_), private, parameter:: psb_char_type     = psb_logical_type  + 1
  integer(psb_mpk_), private, parameter:: psb_int8_type     = psb_char_type     + 1
  integer(psb_mpk_), private, parameter:: psb_int2_type     = psb_int8_type     + 1
  integer(psb_mpk_), private, parameter:: psb_int4_type     = psb_int2_type     + 1
  integer(psb_mpk_), private, parameter:: psb_long_type     = psb_int4_type     + 1


  type psb_buffer_node
    integer(psb_mpk_) :: request
    integer(psb_mpk_) :: icontxt 
    integer(psb_mpk_) :: buffer_type
    integer(psb_epk_), allocatable     :: int8buf(:)
    integer(psb_i2pk_), allocatable    :: int2buf(:)
    integer(psb_mpk_), allocatable     :: int4buf(:)
    real(psb_spk_), allocatable        :: realbuf(:)
    real(psb_dpk_), allocatable        :: doublebuf(:)
    complex(psb_spk_), allocatable     :: complexbuf(:)
    complex(psb_dpk_), allocatable     :: dcomplbuf(:)
    logical, allocatable               :: logbuf(:)
    character(len=1), allocatable      :: charbuf(:)
    type(psb_buffer_node), pointer :: prev=>null(), next=>null()
  end type psb_buffer_node

  type psb_buffer_queue
    type(psb_buffer_node), pointer :: head=>null(), tail=>null()
  end type psb_buffer_queue


  interface psi_snd
    module procedure&
         & psi_msnd, psi_esnd,&
         & psi_ssnd, psi_dsnd,&
         & psi_csnd, psi_zsnd,&
         & psi_logsnd, psi_hsnd,&
         & psi_i2snd
  end interface

contains

  subroutine psb_init_queue(mesg_queue,info)
    implicit none 
    type(psb_buffer_queue), intent(inout) :: mesg_queue
    integer(psb_ipk_), intent(out)                  :: info

    info = 0
    if ((.not.associated(mesg_queue%head)).and.&
         & (.not.associated(mesg_queue%tail))) then 
      ! Nothing to do
      return
    end if

    if ((.not.associated(mesg_queue%head)).or.&
         & (.not.associated(mesg_queue%tail))) then 
      ! If we are here one is associated, the other is not.
      ! This is impossible. 
      info = -1
      write(psb_err_unit,*) 'Wrong status on init '
      return
    end if

  end subroutine psb_init_queue

  subroutine psb_wait_buffer(node, info)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    type(psb_buffer_node), intent(inout) :: node
    integer(psb_ipk_), intent(out) :: info 
    integer(psb_mpk_) :: status(mpi_status_size),minfo
    minfo = mpi_success
    call mpi_wait(node%request,status,minfo)
    info=minfo
  end subroutine psb_wait_buffer

  subroutine psb_test_buffer(node, flag, info)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    type(psb_buffer_node), intent(inout) :: node
    logical, intent(out) :: flag
    integer(psb_ipk_), intent(out) :: info 
    integer(psb_mpk_) :: status(mpi_status_size), minfo
    minfo = mpi_success
#if defined(SERIAL_MPI)
    flag  = .true.
#else
    call mpi_test(node%request,flag,status,minfo)
#endif
    info=minfo
  end subroutine psb_test_buffer
  

  subroutine psb_close_context(mesg_queue,icontxt)
    type(psb_buffer_queue), intent(inout) :: mesg_queue
    integer(psb_mpk_), intent(in) :: icontxt
    integer(psb_ipk_) :: info
    type(psb_buffer_node), pointer :: node, nextnode

    node => mesg_queue%head
    do 
      if (.not.associated(node)) exit
      nextnode => node%next
      if (node%icontxt == icontxt) then 
        call psb_wait_buffer(node,info)
        call psb_delete_node(mesg_queue,node)
      end if
      node => nextnode
    end do
  end subroutine psb_close_context

  subroutine psb_close_all_context(mesg_queue)
    type(psb_buffer_queue), intent(inout) :: mesg_queue
    type(psb_buffer_node), pointer :: node, nextnode
    integer(psb_ipk_) :: info
    
    node => mesg_queue%head
    do 
      if (.not.associated(node)) exit
      nextnode => node%next
      call psb_wait_buffer(node,info)
      call psb_delete_node(mesg_queue,node)
      node => nextnode
    end do
  end subroutine psb_close_all_context


  subroutine psb_delete_node(mesg_queue,node)
    type(psb_buffer_queue), intent(inout) :: mesg_queue
    type(psb_buffer_node), pointer   :: node
    type(psb_buffer_node), pointer  :: prevnode
    
    if (.not.associated(node)) then 
      return
    end if
    prevnode => node%prev
    if (associated(mesg_queue%head,node)) mesg_queue%head => node%next
    if (associated(mesg_queue%tail,node)) mesg_queue%tail => prevnode
    if (associated(prevnode)) prevnode%next => node%next
    if (associated(node%next)) node%next%prev => prevnode
    deallocate(node)
    
  end subroutine psb_delete_node

  subroutine psb_insert_node(mesg_queue,node)
    type(psb_buffer_queue), intent(inout) :: mesg_queue
    type(psb_buffer_node), pointer   :: node

    node%next => null()
    node%prev => null()
    if ((.not.associated(mesg_queue%head)).and.&
         & (.not.associated(mesg_queue%tail))) then 
      mesg_Queue%head => node
      mesg_queue%tail => node
      return
    end if
    mesg_queue%tail%next => node
    node%prev => mesg_queue%tail
    mesg_queue%tail => node

  end subroutine psb_insert_node

  subroutine psb_test_nodes(mesg_queue)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node, nextnode
    integer(psb_ipk_) :: info
    logical :: flag
    
    node => mesg_queue%head
    do 
      if (.not.associated(node)) exit
      nextnode => node%next
      call psb_test_buffer(node,flag,info)
      if (flag) then 
        call psb_delete_node(mesg_queue,node)
      end if
      node => nextnode
    end do
  end subroutine psb_test_nodes

  ! !!!!!!!!!!!!!!!!!
  !
  ! Inner send. Basic idea:
  !  the input buffer is MOVE_ALLOCed
  !  to a node in the mesg queue, then it is sent.
  !  Thus the calling process should guarantee that
  !  the buffer is dispensable, i.e. the user data
  !  has already been copied. 
  !
  ! !!!!!!!!!!!!!!!!!
  subroutine psi_msnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    integer(psb_mpk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo
    
    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_int_type
    call move_alloc(buffer,node%int4buf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%int4buf,size(node%int4buf),psb_mpi_mpk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)

  end subroutine psi_msnd


  subroutine psi_esnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    integer(psb_epk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo
    
    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_int8_type
    call move_alloc(buffer,node%int8buf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%int8buf,size(node%int8buf),psb_mpi_epk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo 
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)

  end subroutine psi_esnd

  subroutine psi_i2snd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    integer(psb_i2pk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo
    
    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_int2_type
    call move_alloc(buffer,node%int2buf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%int2buf,size(node%int2buf),psb_mpi_i2pk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)

  end subroutine psi_i2snd

  subroutine psi_ssnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    real(psb_spk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo

    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_real_type
    call move_alloc(buffer,node%realbuf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%realbuf,size(node%realbuf),psb_mpi_r_spk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)
    
  end subroutine psi_ssnd

  subroutine psi_dsnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    real(psb_dpk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo

    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_double_type
    call move_alloc(buffer,node%doublebuf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%doublebuf,size(node%doublebuf),psb_mpi_r_dpk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)
    
  end subroutine psi_dsnd
    
  subroutine psi_csnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    complex(psb_spk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo

    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_complex_type
    call move_alloc(buffer,node%complexbuf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%complexbuf,size(node%complexbuf),psb_mpi_c_spk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo 
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)
    
  end subroutine psi_csnd

  subroutine psi_zsnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    complex(psb_dpk_), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo
    
    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_dcomplex_type
    call move_alloc(buffer,node%dcomplbuf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%dcomplbuf,size(node%dcomplbuf),psb_mpi_c_dpk_,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)
    
  end subroutine psi_zsnd


  subroutine psi_logsnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    logical, allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo
    
    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_logical_type
    call move_alloc(buffer,node%logbuf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%logbuf,size(node%logbuf),mpi_logical,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)
    
  end subroutine psi_logsnd


  subroutine psi_hsnd(icontxt,tag,dest,buffer,mesg_queue)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_) :: icontxt, tag, dest
    character(len=1), allocatable, intent(inout) :: buffer(:)
    type(psb_buffer_queue) :: mesg_queue
    type(psb_buffer_node), pointer :: node
    integer(psb_ipk_) :: info
    integer(psb_mpk_) :: minfo
    
    allocate(node, stat=info)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    node%icontxt     = icontxt
    node%buffer_type = psb_char_type
    call move_alloc(buffer,node%charbuf)
    if (info /= 0) then 
      write(psb_err_unit,*) 'Fatal memory error inside communication subsystem'
      return
    end if
    call mpi_isend(node%charbuf,size(node%charbuf),mpi_character,&
         & dest,tag,icontxt,node%request,minfo)
    info = minfo
    call psb_insert_node(mesg_queue,node)
    
    call psb_test_nodes(mesg_queue)
    
  end subroutine psi_hsnd


end module psi_comm_buffers_mod