#include <assert.h>

#include <debug.h>

#include <value/struct.h>

#include "linked_list/append.h"
#include "linked_list/remove.h"

#include "dotout.h"
#include "flags.h"
#include "struct.h"
#include "dec_external_refcount.h"

void gc_dec_external_refcount(
    struct gc* this,
    struct value* value)
{
    ENTER;
    
    if (value)
    {
        assert(value->external_refcount > 0);
        
        if (value->external_refcount > 1)
        {
            value->external_refcount--;
        }
        else if (value->external_refcount == 1)
        {
            assert(value->externally_referenced.in_set == true);
            assert(value->internally_referenced.in_set == false);
            assert(value->white.in_set == false);
            assert(value->reaped.in_set == false);
            
            #ifdef DOTOUT_BUILD
            if (this->flags->dotout)
            {
                gc_dotout(this, "gc_dec_external_refcount: before");
            }
            #endif
            
            value->external_refcount--;
            
            linked_list_remove(
                /* linked list: */ &this->externally_referenced,
                /* element: */ value,
                /* link offset: */ offsetof(struct value, externally_referenced));
            
            // it might be in the grey set, but that's okay.
            
            linked_list_append(
                /* linked list: */ &this->internally_referenced,
                /* element: */ value,
                /* link offset: */ offsetof(struct value, internally_referenced));
            
            #ifdef DOTOUT_BUILD
            if (this->flags->dotout)
            {
                gc_dotout(this, "gc_dec_external_refcount: after");
            }
            #endif
            
            assert(value->internally_referenced.in_set);
        }
        else
        {
            NOPE;
        }
    }
    
    EXIT;
}