!-----------------------------------------------------------------------
!-
!       test program for the project "gravity field"
!-
!-----------------------------------------------------------------------
program essai
  use realfield
  use spitpgm               ! XXX

  implicit none

  type(massbody)          :: planets(60)
  integer                 :: foo
  character(len=100)      :: filename

  call init_random()

  call create_some_planets(planets, 45e5)

  do foo=0, 72
    write (filename, "(a, i5.5, a)") 'WS/A', foo, '.pgm'
    call build_and_write_a_field(640, 480, planets, filename)
    print *, trim(filename)
    ! OMG! two magic numbers, wtf?
    planets(1)%posx = planets(1)%posx + 8.08
    planets(1)%posy = planets(1)%posy + 6.42
  enddo

  STOP 'BECAUSE YOLO'

contains
!-----------------------------------------------------------------------
!-
!    Yes, I know, this is a disturbing kluge, but I like it :}
!    May be, it's time to read the doc of modern Fortran
!-
subroutine init_random()

  integer, dimension(3) :: tarray
  integer               :: t3
  real                  :: dummy
  call itime(tarray)
  t3 = 8971*tarray(1) + 443*tarray(2) + tarray(3)
  write(0, '(A,3I3,A,I6)') "sranding: ", tarray, " --> ", t3
  call srand(t3)
  ! after initializing the random generator engine,
  ! you MUST use it for initializing the initializer
  dummy = rand()
  write(0, *) 'dummy was ', dummy

end subroutine
!-----------------------------------------------------------------------
!-
!     make a few solid body to play with...
!-
subroutine create_some_planets(planets, coef)
  type(massbody), intent(inout)     :: planets(:)
  real, intent(in)                  :: coef
  integer                           :: foo
  ! real                              :: quux, quuy
  character(100)                    :: fmt

  fmt = "(I4, '   : ', 2(F9.2, '  '), e11.3, I7)"

  do foo=1, ubound(planets, 1)
    if (foo .EQ. 1) then
      planets(1)%posx   = 20
      planets(1)%posy   = 20
      planets(1)%mass   = 9e8
      planets(1)%serial = 1337
    else
      planets(foo)%posx     = rand() * 639.999
      planets(foo)%posy     = rand() * 479.999
      planets(foo)%mass     = 7e6 + coef*foo
      planets(foo)%serial   = foo
    endif
    write (*, fmt) foo, planets(foo)
  enddo

  ! STOP 'ABEND'

end subroutine
!-----------------------------------------------------------------------
!-
!   compute a field with only one body; and write pic file
!-
subroutine build_and_write_a_field(szx, szy, moons, fname)
  integer, intent(in)                :: szx, szy
  type(massbody), intent(in)         :: moons(:)
  character(len=*), intent(in)       :: fname

  real                                  :: maxi, mini
  integer                               :: errcode, foo
  real,    dimension(:,:), allocatable  :: field, tmpf
  integer, dimension(:,:), allocatable  :: greymap

  allocate(field(szx, szy), stat=errcode)
  allocate(tmpf(szx, szy), stat=errcode)

  field = 0.0
  do foo=1, ubound(moons, 1)
    call compute_a_field(tmpf, moons(foo))
    tmpf = tmpf * 0.019
    field = field + tmpf
  enddo

  maxi = maxval(field)
  mini = minval(field)
  ! print *, "field: ", mini, maxi, maxi-mini

  allocate(greymap(szx, szy), stat=errcode)
  greymap = 0
  ! convert from real value to 16 bits int values
  where (field < 65530.0)
    greymap = int(field)
  end where

  call spit_as_pgm_16(greymap, trim(fname))

  ! make valgrind happy
  deallocate(field)
  deallocate(greymap)

end subroutine

!-----------------------------------------------------------------------
!-----------------------------------------------------------------------

end program