#ifndef SUICMEZ_GC_H
#define SUICMEZ_GC_H

#include <stdint.h>
#include <stddef.h>

#define YOUNG_SIZE       (1024 * 1024 * 2)
#define SURVIVOR_SIZE    (512 * 1024)
#define OLD_SIZE         (16 * 1024 * 1024)
#define CARD_SIZE        512
#define PROMOTION_AGE    2
#define MAX_ROOTS        1024
#define MARKED           0x1

/* Forward declare Obj so ObjHeader can reference it */
typedef struct Obj Obj;

/* Forward declare TypeInfo */
typedef struct TypeInfo TypeInfo;

/* Header must come first */
typedef struct ObjHeader {
    uint32_t size;        // total object size incl header
    uint16_t age;
    uint16_t flags;
    Obj *forwarding;      // non-NULL if moved
    const TypeInfo *type;
} ObjHeader;

struct TypeInfo {
    uint16_t field_count;
    uint16_t pointer_count;
    const uint8_t *pointer_bitmap;
};

/* Full object definition */
struct Obj {
    ObjHeader header;
    void *fields[];
};

// --- API ---
// Initialize the GC
void gc_init(void);

// Shutdown GC
void gc_shutdown(void);

// Allocate object in young generation
void *gc_alloc(const TypeInfo *type, size_t payload_size);

// Root management
void gc_add_root(void **ptr);
void gc_remove_root(void **ptr);

// Write barrier for old->young references
void gc_write_barrier(void *src, void *dst);

// Minor GC slice (incremental)
void gc_minor_collect_slice(size_t max_objects);

// Trigger major GC
void gc_major_collect(void);

static inline void scan_object_fields(Obj *obj);

static void mark_obj(Obj *obj);

void gc_collect_old(void);

#endif // SUICMEZ_GC_H