// smallobject_hotbox_v3_box.h - SmallObject HotHeap v3 (C7-first skeleton)
//
// Phase A/B: 型と TLS / stats を用意し、front が呼べる枠を置く。
//            まだ中身は v1 fallback（so_alloc は NULL を返す）。
#pragma once

#include <stdint.h>
#include <stddef.h>
#include <stdatomic.h>
#include "tiny_geometry_box.h"
#include "smallobject_hotbox_v3_env_box.h"
#include "tiny_region_id.h"

#ifndef SMALLOBJECT_NUM_CLASSES
#define SMALLOBJECT_NUM_CLASSES TINY_NUM_CLASSES
#endif

struct tiny_heap_page_t;
struct TinySlabMeta;
struct SuperSlab;

typedef struct so_page_v3 {
    void* freelist;
    uint32_t used;
    uint32_t capacity;
    uint32_t block_size;
    uint32_t class_idx;
    uint32_t flags;
    void* base;       // carve 後のユーザ領域先頭
    void* slab_base;  // 64KiB slab 基底（page_of 用ヘッダを書き込む）
    struct TinySlabMeta* meta;
    struct SuperSlab* ss;
    uint16_t slab_idx;
    struct tiny_heap_page_t* lease_page;
    void* slab_ref;  // kept as a generic token; currently same as lease_page for v1
    struct so_page_v3* next;
} so_page_v3;

typedef struct so_class_v3 {
    so_page_v3* current;
    so_page_v3* partial;
    uint16_t max_partial_pages;
    uint16_t partial_count;
    uint32_t block_size;
} so_class_v3;

typedef struct so_ctx_v3 {
    so_class_v3 cls[SMALLOBJECT_NUM_CLASSES];
} so_ctx_v3;

typedef struct so_stats_class_v3 {
    _Atomic uint64_t route_hits;
    _Atomic uint64_t alloc_calls;
    _Atomic uint64_t alloc_refill;
    _Atomic uint64_t alloc_fallback_v1;
    _Atomic uint64_t alloc_current_hit;      // fast path: current から pop
    _Atomic uint64_t alloc_partial_hit;      // fast path: partial から pop
    _Atomic uint64_t free_calls;
    _Atomic uint64_t free_fallback_v1;
    _Atomic uint64_t free_current;           // fast path: current に push
    _Atomic uint64_t free_partial;           // fast path: partial に push
    _Atomic uint64_t free_retire;            // slow path: retire
    _Atomic uint64_t page_of_fail;
} so_stats_class_v3;

// Stats helpers (defined in core/smallobject_hotbox_v3.c)
int so_v3_stats_enabled(void);
void so_v3_record_route_hit(uint8_t ci);
void so_v3_record_alloc_call(uint8_t ci);
void so_v3_record_alloc_refill(uint8_t ci);
void so_v3_record_alloc_fallback(uint8_t ci);
void so_v3_record_alloc_current_hit(uint8_t ci);
void so_v3_record_alloc_partial_hit(uint8_t ci);
void so_v3_record_free_call(uint8_t ci);
void so_v3_record_free_fallback(uint8_t ci);
void so_v3_record_free_current(uint8_t ci);
void so_v3_record_free_partial(uint8_t ci);
void so_v3_record_free_retire(uint8_t ci);
void so_v3_record_page_of_fail(uint8_t ci);

// TLS accessor (core/smallobject_hotbox_v3.c)
so_ctx_v3* so_tls_get(void);

// Hot path API (Phase B: stub → always fallback to v1)
void* so_alloc(uint32_t class_idx);
void so_free(uint32_t class_idx, void* ptr);

// C7-only pointer membership check (read-only, no state change)
int smallobject_hotbox_v3_can_own_c7(void* ptr);