#ifndef INCLUDED_GC_H
#define INCLUDED_GC_H

#include "memory.h"

#include <stddef.h>
#include <stdio.h>
#include <threads.h>

#define OBJECT_PROCESS_STACK_BLOCK_SIZE 64
struct ObjectProcessStackBlock {
    void *objs[OBJECT_PROCESS_STACK_BLOCK_SIZE];
};
typedef struct {
    size_t num_blocks;
    size_t num_objs;
    struct ObjectProcessStackBlock **blocks;
} ObjectProcessStack;

static ALWAYS_INLINE bool
OBJECT_PROCESS_STACK_EMPTY_P(ObjectProcessStack *restrict stack) {
    return !stack->num_objs;
}

static ALWAYS_INLINE void
init_object_process_stack(ObjectProcessStack *restrict stack) {
    stack->num_blocks = 0;
    stack->num_objs = 0;
    stack->blocks = NULL;
}

void free_object_process_stack(ObjectProcessStack *restrict stack);
void object_process_stack_push_object(ObjectProcessStack *restrict stack,
                                      void *obj);
void object_process_stack_push_held_objects(ObjectProcessStack *restrict stack,
                                            void *obj);
void *object_process_stack_pop(ObjectProcessStack *restrict stack);

extern bool lisp_doing_gc;
extern struct timespec total_gc_time;
extern size_t total_gc_count;

typedef struct {
    size_t non_statics_kept;
    size_t objects_cleaned;
    struct timespec ellapsed_time;
} LispGCStats;

typedef uint8_t ObjectGCSet;

extern ObjectGCSet GC_BLACK;
extern ObjectGCSet GC_GREY;
extern ObjectGCSet GC_WHITE;

struct GCObjectList;

typedef struct {
    unsigned int is_static : 1;
    ObjectGCSet set : 2;
    tss_t has_local_ref;
    struct GCObjectList *gc_node;
} ObjectGCInfo;

// the argument is a LispVal *
void lisp_gc_register_object(void *val);
void lisp_gc_register_static_object(void *val);
void gc_move_to_set(void *val, ObjectGCSet new_set);

// note that the argument is restrict!
void lisp_gc_now(LispGCStats *restrict status);

// Debug
void debug_print_gc_stats(FILE *stream, const LispGCStats *stats);

#endif