module clp_callback
use iso_c_binding
implicit none

    interface fortran_cb
        subroutine fortran_cb(mdl, msg, dbls, ints, strings)
        use iso_c_binding
        use clp_constants
        implicit none
            type(c_ptr) :: mdl
            integer :: msg
            real(kind=c_double), dimension(:), pointer :: dbls
            integer(kind=c_int), dimension(:), pointer :: ints
            character(len=clp_default_message_len), dimension(:), pointer :: strings
        end subroutine fortran_cb
    end interface
    
    procedure(fortran_cb), pointer:: current_callback
    
contains

    subroutine Clp_boundCallbackInterface(model, messageNumber, &
                                          nDouble, vDouble, &
                                          nInt, vInt, &
                                          nString, vString) bind(C)
    use iso_c_binding
    use clp_constants
    implicit none
    
        type(c_ptr), value :: model
        integer(c_int), value :: messageNumber
        integer(c_int), value :: nDouble, nInt, nString
        type(c_ptr), value :: vDouble, vInt, vString
        
        real(kind=c_double), dimension(:), pointer :: fdouble
        integer(kind=c_int), dimension(:), pointer :: fint
        character(len=clp_default_message_len), dimension(:), pointer :: fstrs
        
        ! For converting C strings
        type(c_ptr), dimension(:), pointer :: c_strings
        integer::i
    
        if(nDouble > 0 .and. c_associated(vDouble)) then
            call c_f_pointer(vDouble, fdouble, (/ nDouble /))
        end if
        
        if(nInt > 0 .and. c_associated(vInt)) then
            call c_f_pointer(vInt, fint, (/ nInt /))
        end if
        
        if(nString > 0 .and. c_associated(vString)) then
            allocate(fstrs(nString))
            fstrs = ' '
            call c_f_pointer(vString, c_strings, (/ nString /))
            do i = 1, nString
                call populate_fortran_string(c_strings(i), fstrs(i))
            end do
        end if
        
        ! Now that Fortran arrays are built, call the Fortran callback
        if(associated(current_callback)) then
            call current_callback(model, messageNumber, fdouble, fint, fstrs)
        end if
        
        if(associated(fstrs)) then
            deallocate(fstrs)
        end if
    
    end subroutine Clp_boundCallbackInterface
    
end module clp_callback