// smallobject_v6_env_box.h - SmallObject v6 ENV Control Box (Headerless Mode)
//
// Phase V6-HDR-2: Additional ENV control for headerless mode
// - Uses tiny_route_env_box.h for v6_enabled and class_enabled
// - Adds headerless-specific ENV gates

#ifndef HAKMEM_SMALLOBJECT_V6_ENV_BOX_H
#define HAKMEM_SMALLOBJECT_V6_ENV_BOX_H

#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include "tiny_route_env_box.h"  // For small_heap_v6_enabled, small_heap_v6_class_enabled

#ifndef likely
#define likely(x)   __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
#endif

// ============================================================================
// ENV: HAKMEM_SMALL_HEAP_V6_HEADERLESS
// ============================================================================
// Enable headerless mode for v6. Default OFF.
// When ON:
//   - free: use RegionIdBox lookup instead of header
//   - alloc: skip header write (rely on carve-time header)

#define V6_HEADERLESS_UNINIT   (-1)
#define V6_HEADERLESS_OFF      0
#define V6_HEADERLESS_ON       1

static int g_small_heap_v6_headerless = V6_HEADERLESS_UNINIT;

static inline bool small_heap_v6_headerless_enabled(void) {
    if (unlikely(g_small_heap_v6_headerless == V6_HEADERLESS_UNINIT)) {
        const char* env = getenv("HAKMEM_SMALL_HEAP_V6_HEADERLESS");
        g_small_heap_v6_headerless = (env && env[0] == '1') ? V6_HEADERLESS_ON : V6_HEADERLESS_OFF;
    }
    return g_small_heap_v6_headerless == V6_HEADERLESS_ON;
}

// ============================================================================
// ENV: HAKMEM_SMALL_V6_REGION_OBSERVE (moved from smallobject_core_v6.c)
// ============================================================================
// Enable OBSERVE mode for class_idx validation. Default OFF.

#define V6_REGION_OBS_UNINIT   (-1)
#define V6_REGION_OBS_OFF      0
#define V6_REGION_OBS_ON       1

static int g_small_v6_region_observe_env = V6_REGION_OBS_UNINIT;

static inline bool small_v6_region_observe_enabled(void) {
    if (unlikely(g_small_v6_region_observe_env == V6_REGION_OBS_UNINIT)) {
        const char* env = getenv("HAKMEM_SMALL_V6_REGION_OBSERVE");
        g_small_v6_region_observe_env = (env && env[0] == '1') ? V6_REGION_OBS_ON : V6_REGION_OBS_OFF;
    }
    return g_small_v6_region_observe_env == V6_REGION_OBS_ON;
}

// ============================================================================
// Combined Gate: v6 headerless route enabled for class
// ============================================================================

/// Check if v6 headerless route is enabled for a given class
/// Uses small_heap_v6_enabled() and small_heap_v6_class_enabled() from tiny_route_env_box.h
/// @param class_idx: class index (4=C4, 5=C5, 6=C6)
/// @return: true if v6 headerless free/alloc should be used
static inline bool small_v6_headerless_route_enabled(uint8_t class_idx) {
    return small_heap_v6_enabled() &&
           small_heap_v6_headerless_enabled() &&
           small_heap_v6_class_enabled((uint32_t)class_idx);
}

// ============================================================================
// Debug: Dump ENV state
// ============================================================================

static inline void small_v6_env_dump(void) {
    // Force init
    (void)small_heap_v6_enabled();
    (void)small_heap_v6_headerless_enabled();
    (void)small_v6_region_observe_enabled();

    fprintf(stderr, "[V6_ENV] enabled=%d headerless=%d observe=%d\n",
            small_heap_v6_enabled() ? 1 : 0,
            g_small_heap_v6_headerless == V6_HEADERLESS_ON,
            g_small_v6_region_observe_env == V6_REGION_OBS_ON);
}

#endif // HAKMEM_SMALLOBJECT_V6_ENV_BOX_H