const prometheus = require('prom-client');

// Player metrics
const activePlayers = new prometheus.Gauge({
  name: 'game_active_players',
  help: 'Currently connected players',
  labelNames: ['region', 'game_mode']
});

const matchesInProgress = new prometheus.Gauge({
  name: 'game_matches_active',
  help: 'Active matches',
  labelNames: ['game_mode']
});

// Performance metrics
const tickDuration = new prometheus.Histogram({
  name: 'game_tick_duration_seconds',
  help: 'Game loop tick duration',
  buckets: [0.001, 0.005, 0.01, 0.016, 0.033]
});

const networkLatency = new prometheus.Histogram({
  name: 'game_network_latency_ms',
  help: 'Player network latency',
  labelNames: ['region'],
  buckets: [10, 25, 50, 75, 100, 150, 200]
});

groups:
- name: game-alerts
  rules:
  - alert: GameServerDown
    expr: up{job="game-servers"} == 0
    for: 1m
    labels:
      severity: critical

  - alert: HighTickLatency
    expr: histogram_quantile(0.99, game_tick_duration_seconds) > 0.02
    for: 5m
    labels:
      severity: high

  - alert: LowPlayerCount
    expr: game_active_players < 10
    for: 10m
    labels:
      severity: warning

# Check Prometheus targets
curl localhost:9090/api/v1/targets | jq '.data.activeTargets'

# Check firing alerts
curl localhost:9090/api/v1/alerts | jq '.data.alerts'

# Query metrics
curl 'localhost:9090/api/v1/query?query=game_active_players'

describe('Metrics', () => {
  test('records tick duration', async () => {
    const end = tickDuration.startTimer();
    await sleep(10);
    end();

    const metrics = await prometheus.register.metrics();
    expect(metrics).toContain('game_tick_duration_seconds');
  });
});