// hakmem_stats_master.h - Master Stats/Dump Control
//
// ENV Cleanup Phase 4d: Unified stats/dump control
//
// Usage:
//   HAKMEM_STATS=all              Enable ALL stats modules
//   HAKMEM_STATS=sfc,fast,refill  Enable specific modules (comma-separated)
//   HAKMEM_STATS_DUMP=1           Dump stats at exit (atexit handler)
//
// Available stats modules:
//   sfc       - Super Front Cache (HAKMEM_SFC_STATS_DUMP)
//   fast      - Fast cache (HAKMEM_TINY_FAST_STATS)
//   heap      - Heap V2 (HAKMEM_TINY_HEAP_V2_STATS)
//   refill    - Refill stats (HAKMEM_TINY_REFILL_DUMP)
//   counters  - Counters (HAKMEM_TINY_COUNTERS_DUMP)
//   ring      - Debug ring (HAKMEM_TINY_DUMP_RING_ATEXIT)
//   invariant - Invariant checks (HAKMEM_TINY_INVARIANT_DUMP)
//   pagefault - Page fault telemetry (HAKMEM_TINY_PAGEFAULT_DUMP)
//   front     - Front metrics (HAKMEM_TINY_FRONT_DUMP)
//   pool      - Shared pool (HAKMEM_SHARED_POOL_STAGE_STATS)
//   slim      - Ultra slim (HAKMEM_ULTRA_SLIM_STATS)
//   guard     - External guard (HAKMEM_EXTERNAL_GUARD_STATS)
//   nearempty - Near empty (HAKMEM_TINY_NEAREMPTY_DUMP)
//
// Priority (highest to lowest):
//   1. HAKMEM_QUIET=1 → suppress all stats output
//   2. Specific module ENV (e.g., HAKMEM_SFC_STATS_DUMP=1) → use that value
//   3. HAKMEM_STATS=module1,module2 → enable listed modules
//   4. HAKMEM_STATS=all → enable all
//   5. Default → disabled
//
// Integration example:
//   Old: static int dump = -1;
//        if (dump==-1) { const char* e = getenv("HAKMEM_FOO_DUMP"); dump = (e && *e != '0') ? 1 : 0; }
//
//   New: static int dump = -1;
//        if (dump==-1) { dump = hak_stats_check("HAKMEM_FOO_DUMP", "foo"); }

#ifndef HAKMEM_STATS_MASTER_H
#define HAKMEM_STATS_MASTER_H

#include <stdlib.h>
#include <string.h>

// Stats module flags (bit positions)
#define HAK_STATS_SFC       (1 << 0)
#define HAK_STATS_FAST      (1 << 1)
#define HAK_STATS_HEAP      (1 << 2)
#define HAK_STATS_REFILL    (1 << 3)
#define HAK_STATS_COUNTERS  (1 << 4)
#define HAK_STATS_RING      (1 << 5)
#define HAK_STATS_INVARIANT (1 << 6)
#define HAK_STATS_PAGEFAULT (1 << 7)
#define HAK_STATS_FRONT     (1 << 8)
#define HAK_STATS_POOL      (1 << 9)
#define HAK_STATS_SLIM      (1 << 10)
#define HAK_STATS_GUARD     (1 << 11)
#define HAK_STATS_NEAREMPTY (1 << 12)
#define HAK_STATS_ALL       0xFFFFFFFF

// Master stats state (cached at first access)
static int g_stats_master_mask = -1;  // -1 = uninitialized
static int g_stats_dump_atexit = -1;
static int g_stats_quiet = -1;

// Map module name to bit flag
static inline int hak_stats_name_to_flag(const char* name) {
    if (!name || !*name) return 0;
    if (strcmp(name, "all") == 0) return HAK_STATS_ALL;
    if (strcmp(name, "sfc") == 0) return HAK_STATS_SFC;
    if (strcmp(name, "fast") == 0) return HAK_STATS_FAST;
    if (strcmp(name, "heap") == 0) return HAK_STATS_HEAP;
    if (strcmp(name, "refill") == 0) return HAK_STATS_REFILL;
    if (strcmp(name, "counters") == 0) return HAK_STATS_COUNTERS;
    if (strcmp(name, "ring") == 0) return HAK_STATS_RING;
    if (strcmp(name, "invariant") == 0) return HAK_STATS_INVARIANT;
    if (strcmp(name, "pagefault") == 0) return HAK_STATS_PAGEFAULT;
    if (strcmp(name, "front") == 0) return HAK_STATS_FRONT;
    if (strcmp(name, "pool") == 0) return HAK_STATS_POOL;
    if (strcmp(name, "slim") == 0) return HAK_STATS_SLIM;
    if (strcmp(name, "guard") == 0) return HAK_STATS_GUARD;
    if (strcmp(name, "nearempty") == 0) return HAK_STATS_NEAREMPTY;
    return 0;
}

// Parse comma-separated module list
static inline int hak_stats_parse_modules(const char* str) {
    if (!str || !*str) return 0;

    int mask = 0;
    char buf[256];
    strncpy(buf, str, sizeof(buf) - 1);
    buf[sizeof(buf) - 1] = '\0';

    char* token = strtok(buf, ",");
    while (token) {
        // Trim whitespace
        while (*token == ' ') token++;
        char* end = token + strlen(token) - 1;
        while (end > token && *end == ' ') *end-- = '\0';

        mask |= hak_stats_name_to_flag(token);
        token = strtok(NULL, ",");
    }
    return mask;
}

// Initialize master stats settings (called once, lazily)
static inline void hak_stats_master_init(void) {
    if (__builtin_expect(g_stats_master_mask >= 0, 1)) return;

    // Check HAKMEM_QUIET first (highest priority)
    const char* quiet = getenv("HAKMEM_QUIET");
    g_stats_quiet = (quiet && *quiet && *quiet != '0') ? 1 : 0;

    // Check HAKMEM_STATS
    const char* stats = getenv("HAKMEM_STATS");
    g_stats_master_mask = hak_stats_parse_modules(stats);

    // Check HAKMEM_STATS_DUMP (dump at exit)
    const char* dump = getenv("HAKMEM_STATS_DUMP");
    g_stats_dump_atexit = (dump && *dump && *dump != '0') ? 1 :
                          (g_stats_master_mask > 0 ? 1 : 0);
}

// Check if a specific stats module should be enabled
// env_name: The specific ENV variable (e.g., "HAKMEM_SFC_STATS_DUMP")
// module: The module name for HAKMEM_STATS (e.g., "sfc")
// Returns: 1 if stats should be enabled, 0 otherwise
static inline int hak_stats_check(const char* env_name, const char* module) {
    hak_stats_master_init();

    // HAKMEM_QUIET overrides everything
    if (g_stats_quiet) return 0;

    // Check specific ENV first (allows explicit enable/disable)
    const char* e = getenv(env_name);
    if (e && *e) {
        return (*e != '0') ? 1 : 0;
    }

    // Fall back to master stats mask
    int flag = hak_stats_name_to_flag(module);
    if (flag && (g_stats_master_mask & flag)) return 1;

    return 0;
}

// Check if stats dump at exit is enabled
static inline int hak_stats_dump_enabled(void) {
    hak_stats_master_init();
    return g_stats_quiet ? 0 : g_stats_dump_atexit;
}

#endif // HAKMEM_STATS_MASTER_H