// pool_hotbox_v2_box.h — Experimental PoolHotBox v2 (hot path scaffold)
#ifndef POOL_HOTBOX_V2_BOX_H
#define POOL_HOTBOX_V2_BOX_H

#include <stdint.h>
#include <stdlib.h>
#include <stdatomic.h>

#include "hakmem_pool.h"  // for POOL_NUM_CLASSES and size helpers

// ENV gates (bench/実験専用):
//   HAKMEM_POOL_V2_ENABLED     : overall ON/OFF (default OFF)
//   HAKMEM_POOL_V2_CLASSES     : bitmask, bit i=1 → class i を HotBox v2 に載せる
//   HAKMEM_POOL_V2_STATS       : stats dump ON/OFF

typedef struct PoolHotBoxV2Stats {
    _Atomic uint64_t alloc_calls;
    _Atomic uint64_t alloc_fast;
    _Atomic uint64_t alloc_refill;
    _Atomic uint64_t alloc_refill_fail;
    _Atomic uint64_t alloc_fallback_v1;
    _Atomic uint64_t free_calls;
    _Atomic uint64_t free_fast;
    _Atomic uint64_t free_fallback_v1;
    _Atomic uint64_t page_of_fail_header_missing;
    _Atomic uint64_t page_of_fail_out_of_range;
    _Atomic uint64_t page_of_fail_misaligned;
    _Atomic uint64_t page_of_fail_unknown;
} PoolHotBoxV2Stats;

// Simple page/class structs for future HotBox v2 implementation.
typedef struct pool_page_v2 {
    void*        freelist;
    uint32_t     used;
    uint32_t     capacity;
    uint32_t     block_size;
    uint32_t     class_idx;
    void*        base;
    void*        slab_ref;
    struct pool_page_v2* next;
} pool_page_v2;

typedef struct pool_class_v2 {
    pool_page_v2* current;
    pool_page_v2* partial;
    uint16_t      max_partial_pages;
    uint16_t      partial_count;
    uint32_t      block_size;
} pool_class_v2;

typedef struct pool_ctx_v2 {
    pool_class_v2 cls[POOL_NUM_CLASSES];
} pool_ctx_v2;

typedef struct PoolColdIface {
    void* (*refill_page)(void* cold_ctx,
                         uint32_t class_idx,
                         uint32_t* out_block_size,
                         uint32_t* out_capacity,
                         void** out_slab_ref);
    void  (*retire_page)(void* cold_ctx,
                         uint32_t class_idx,
                         void* slab_ref,
                         void* base);
} PoolColdIface;

// ENV helpers
int pool_hotbox_v2_class_enabled(int class_idx);
int pool_hotbox_v2_stats_enabled(void);

// TLS/context helpers
pool_ctx_v2* pool_v2_tls_get(void);

// Hot path (currently stubbed to always fall back to v1; structure only)
void* pool_hotbox_v2_alloc(uint32_t class_idx, size_t size, uintptr_t site_id);
int   pool_hotbox_v2_free(uint32_t class_idx, void* raw_block);

// Stats helpers
void pool_hotbox_v2_record_free_call(uint32_t class_idx);
void pool_hotbox_v2_record_alloc_fallback(uint32_t class_idx);
void pool_hotbox_v2_record_free_fallback(uint32_t class_idx);

// Stats export (destructor in hakmem_pool.c)
extern PoolHotBoxV2Stats g_pool_hotbox_v2_stats[POOL_NUM_CLASSES];

#endif  // POOL_HOTBOX_V2_BOX_H