#pragma once
/*
 * ctrl_metrics.h — P3-7: Operational metrics for the XCE controller.
 *
 * All metrics use C11 _Atomic uint64_t for lock-free, thread-safe access.
 * Metric names use the ctrl_ prefix.
 *
 * Design doc: Part P3-7, review A8-007.
 */
#include <stdatomic.h>
#include <stdint.h>

/* ── Counter/gauge globals ──────────────────────────────────────────── */
extern _Atomic uint64_t ctrl_repl_degraded_count;    /* counter */
extern _Atomic uint64_t ctrl_split_brain_detected;   /* counter */
extern _Atomic uint64_t ctrl_async_events_lost;      /* counter */
extern _Atomic uint64_t ctrl_transient_jobs_stuck;   /* counter */
extern _Atomic uint64_t ctrl_wal_bytes;              /* gauge   */
extern _Atomic uint64_t ctrl_checkpoint_duration_ms; /* gauge   */
extern _Atomic uint64_t ctrl_repl_lag_lsn;           /* gauge   */

/* ── Macros ─────────────────────────────────────────────────────────── */

/* Increment a monotonic counter by 1 (relaxed ordering — counters are
 * sampled, not used for synchronization). */
#define CTRL_METRIC_INC(name) \
    atomic_fetch_add_explicit(&(name), 1, memory_order_relaxed)

/* Overwrite a gauge with a new absolute value. */
#define CTRL_METRIC_SET(name, val) \
    atomic_store_explicit(&(name), (uint64_t)(val), memory_order_relaxed)

/* ── Descriptor table for metric discovery ──────────────────────────── */
typedef struct {
    const char*        name;
    _Atomic uint64_t*  value;
    const char*        description;
    int                is_counter; /* 1 = counter (monotonic), 0 = gauge */
} ctrl_metric_desc_t;

/* Terminated by a { NULL, NULL, NULL, 0 } sentinel entry. */
extern const ctrl_metric_desc_t ctrl_metric_descriptors[];

/* ── Lifecycle ──────────────────────────────────────────────────────── */

/* Reset all metrics to zero. Call from persist_start() and ha_init(). */
void ctrl_metrics_init(void);