/* test_ctrl_metrics.c — P3-7: Metrics infrastructure unit tests
 *
 * TDD: these tests are written FIRST to drive the implementation.
 * They verify:
 *   - ctrl_metrics_init() zeroes all 7 counters/gauges
 *   - CTRL_METRIC_INC increments atomically
 *   - CTRL_METRIC_SET writes and overwrites a gauge
 *   - The descriptor table has exactly 7 entries + NULL sentinel
 *   - ctrl_transient_jobs_stuck counter accumulates correctly
 */
#define _GNU_SOURCE
#include <stdatomic.h>
#include <stdint.h>
#include <stdio.h>

#include <unity/unity.h>

#include "ctrl_metrics.h"

/* ------------------------------------------------------------------ */
/* Tests                                                               */
/* ------------------------------------------------------------------ */

static void test_metrics_init_zeros_all_counters(void)
{
    ctrl_metrics_init();
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_repl_degraded_count));
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_split_brain_detected));
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_async_events_lost));
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_transient_jobs_stuck));
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_wal_bytes));
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_checkpoint_duration_ms));
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_repl_lag_lsn));
    printf("test_metrics_init_zeros_all_counters: PASS\n");
}

static void test_metrics_increment_repl_degraded(void)
{
    ctrl_metrics_init();
    CTRL_METRIC_INC(ctrl_repl_degraded_count);
    CTRL_METRIC_INC(ctrl_repl_degraded_count);
    TEST_ASSERT_EQUAL_UINT64(2, atomic_load(&ctrl_repl_degraded_count));
    printf("test_metrics_increment_repl_degraded: PASS\n");
}

static void test_metrics_set_gauge(void)
{
    ctrl_metrics_init();
    CTRL_METRIC_SET(ctrl_wal_bytes, 1024 * 1024);
    TEST_ASSERT_EQUAL_UINT64(1024 * 1024, atomic_load(&ctrl_wal_bytes));
    CTRL_METRIC_SET(ctrl_wal_bytes, 0);
    TEST_ASSERT_EQUAL_UINT64(0, atomic_load(&ctrl_wal_bytes));
    printf("test_metrics_set_gauge: PASS\n");
}

static void test_metrics_descriptor_table_has_sentinel(void)
{
    /* The descriptor table must end with a NULL-name sentinel
     * and contain exactly 7 real entries. */
    int i = 0;
    while (ctrl_metric_descriptors[i].name != NULL)
        i++;
    TEST_ASSERT_EQUAL_INT(7, i);
    printf("test_metrics_descriptor_table_has_sentinel: PASS\n");
}

static void test_transient_jobs_stuck_counter(void)
{
    ctrl_metrics_init();
    /* Simulate 3 stuck transient jobs */
    for (int j = 0; j < 3; j++)
        CTRL_METRIC_INC(ctrl_transient_jobs_stuck);
    TEST_ASSERT_EQUAL_UINT64(3, atomic_load(&ctrl_transient_jobs_stuck));
    printf("test_transient_jobs_stuck_counter: PASS\n");
}

/* ------------------------------------------------------------------ */
/* Suite entry point (called from controller_test.c)                   */
/* ------------------------------------------------------------------ */

void test_ctrl_metrics(void)
{
    RUN_TEST(test_metrics_init_zeros_all_counters);
    RUN_TEST(test_metrics_increment_repl_degraded);
    RUN_TEST(test_metrics_set_gauge);
    RUN_TEST(test_metrics_descriptor_table_has_sentinel);
    RUN_TEST(test_transient_jobs_stuck_counter);
}