/*
 * ctrl_metrics.c — P3-7: Operational metrics for the XCE controller.
 *
 * Defines the 7 atomic counters/gauges and the descriptor table used
 * for metric discovery.  All variables are initialised to 0 at program
 * start (C guarantees this for file-scope variables), and are zeroed
 * explicitly by ctrl_metrics_init() which is called from persist_start()
 * so that tests can call it repeatedly without interference.
 */
#include "ctrl_metrics.h"

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

/* ── Counter/gauge definitions ──────────────────────────────────────── */
_Atomic uint64_t ctrl_repl_degraded_count    = 0;
_Atomic uint64_t ctrl_split_brain_detected   = 0;
_Atomic uint64_t ctrl_async_events_lost      = 0;
_Atomic uint64_t ctrl_transient_jobs_stuck   = 0;
_Atomic uint64_t ctrl_wal_bytes              = 0;
_Atomic uint64_t ctrl_checkpoint_duration_ms = 0;
_Atomic uint64_t ctrl_repl_lag_lsn           = 0;

/* ── Descriptor table ───────────────────────────────────────────────── */
const ctrl_metric_desc_t ctrl_metric_descriptors[] = {
    { "ctrl_repl_degraded_count",
      &ctrl_repl_degraded_count,
      "Sync replication fallbacks to local-only durability",
      1 },
    { "ctrl_split_brain_detected",
      &ctrl_split_brain_detected,
      "Term conflicts indicating split-brain risk",
      1 },
    { "ctrl_async_events_lost",
      &ctrl_async_events_lost,
      "Async WAL entries lost during failover",
      1 },
    { "ctrl_transient_jobs_stuck",
      &ctrl_transient_jobs_stuck,
      "TRANSIENT jobs auto-terminated after timeout",
      1 },
    { "ctrl_wal_bytes",
      &ctrl_wal_bytes,
      "Current WAL size in bytes",
      0 },
    { "ctrl_checkpoint_duration_ms",
      &ctrl_checkpoint_duration_ms,
      "Duration of last checkpoint in milliseconds",
      0 },
    { "ctrl_repl_lag_lsn",
      &ctrl_repl_lag_lsn,
      "LSN gap between primary and slowest standby",
      0 },
    { NULL, NULL, NULL, 0 }  /* sentinel */
};

/* ── ctrl_metrics_init ──────────────────────────────────────────────── */
void ctrl_metrics_init(void)
{
    atomic_store_explicit(&ctrl_repl_degraded_count,    0, memory_order_relaxed);
    atomic_store_explicit(&ctrl_split_brain_detected,   0, memory_order_relaxed);
    atomic_store_explicit(&ctrl_async_events_lost,      0, memory_order_relaxed);
    atomic_store_explicit(&ctrl_transient_jobs_stuck,   0, memory_order_relaxed);
    atomic_store_explicit(&ctrl_wal_bytes,              0, memory_order_relaxed);
    atomic_store_explicit(&ctrl_checkpoint_duration_ms, 0, memory_order_relaxed);
    atomic_store_explicit(&ctrl_repl_lag_lsn,           0, memory_order_relaxed);
}