// hakmem_tiny_slow.inc
// Slow path allocation implementation

#include "box/tiny_heap_env_box.h"   // tiny_c7_heap_mode_enabled()
#include "box/tiny_c7_hotbox.h"      // tiny_c7_alloc_fast (TinyHeapBox 経由)

// Slow path allocation function
// Phase 6-1.7: Export for box refactor (Box 5 needs access from hakmem.c)
#ifdef HAKMEM_TINY_PHASE6_BOX_REFACTOR
void* __attribute__((cold, noinline)) hak_tiny_alloc_slow(size_t size, int class_idx) {
#else
static void* __attribute__((cold, noinline)) hak_tiny_alloc_slow(size_t size, int class_idx) {
#endif
    (void)size; // size is already validated by caller

    if (class_idx < 0 || class_idx >= TINY_NUM_CLASSES) {
        return NULL;
    }

    // C7 TinyHeap front ON のときは旧 slow path を通さず TinyHeapBox に委譲する。
    if (__builtin_expect(class_idx == 7 && tiny_c7_heap_mode_enabled(), 0)) {
        return tiny_c7_alloc_fast(size);
    }

    // Try refilling from HotMag
    if (g_hotmag_enable && class_idx <= 3) {
        TinyHotMag* hm = &g_tls_hot_mag[class_idx];
        hotmag_try_refill(class_idx, hm);
        void* ptr = hotmag_pop(class_idx);
        if (ptr) { HAK_RET_ALLOC(class_idx, ptr); }
    }

    // Try TLS SLL via Box (Phase12 正式経路)
    // C7 は headerless: 既存仕様通り TLS/SLL をスキップ
    if (g_tls_sll_enable && class_idx != 7) {
        // Box: 単一APIで TLS SLL を扱う（内部で head/count/next を管理）
        void* ptr = NULL;
        if (tls_sll_pop(class_idx, &ptr)) {
            return ptr;
        }
    }

    // Try TLS list (legacy small-mag) via既存API（構造体直接触らない）
    if (g_tls_list_enable && class_idx != 7) {
        TinyTLSList* tls = &g_tls_lists[class_idx];

        // Fail-Fast: guard against poisoned head (remote sentinel)
        if (__builtin_expect((uintptr_t)tls->head == TINY_REMOTE_SENTINEL, 0)) {
            tls->head = NULL;
            tls->count = 0;
        }

        if (tls->count > 0) {
            void* ptr = tls_list_pop(tls, class_idx);
            if (ptr) {
                HAK_RET_ALLOC(class_idx, ptr);
            }
        }

        // Try refilling TLS list from TLS-cached Superslab slab
        uint32_t want = tls->refill_low > 0 ? tls->refill_low : 32;
        if (tls_refill_from_tls_slab(class_idx, tls, want) > 0) {
            void* ptr = tls_list_pop(tls, class_idx);
            if (ptr) {
                HAK_RET_ALLOC(class_idx, ptr);
            }
        }
    }

    // Background coalescing/aggregation (ENV removed, fixed OFF)
    do {
        (void)class_idx; // Background steps disabled
    } while (0);

    // Final fallback: allocate from superslab via Box API wrapper (Stage A)
    // NOTE:
    //  - hak_tiny_alloc_superslab_box() is a thin façade over the legacy
    //    per-class SuperslabHead backend in Phase 12 Stage A.
    //  - Callers (slow path) no longer depend on internal Superslab layout.
    void* ss_ptr = hak_tiny_alloc_superslab_box(class_idx);

    if (ss_ptr) {
        HAK_RET_ALLOC(class_idx, ss_ptr);
    }

#if !HAKMEM_BUILD_RELEASE
    tiny_alloc_dump_tls_state(class_idx, "slow_fail", &g_tls_slabs[class_idx]);
    // Optional one-shot debug when final slow path fails
    static int g_alloc_dbg = -1; if (__builtin_expect(g_alloc_dbg == -1, 0)) { const char* e=getenv("HAKMEM_TINY_ALLOC_DEBUG"); g_alloc_dbg = (e && atoi(e)!=0)?1:0; }
    if (g_alloc_dbg) {
        static _Atomic int printed[8]; int exp=0;
        if (atomic_compare_exchange_strong(&printed[class_idx], &exp, 1)) {
            fprintf(stderr, "[ALLOC-SLOW] hak_tiny_alloc_superslab returned NULL class=%d size=%zu\n", class_idx, size);
        }
    }
#endif

    return ss_ptr;
}