package metrics

// Tests for Prometheus metrics registration with a custom registry.

import (
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	"github.com/stretchr/testify/require"
)

// TestNewMetrics_WithCustomRegistry verifies metrics register on a provided registry.
func TestNewMetrics_WithCustomRegistry(t *testing.T) {
	registry := prometheus.NewRegistry()
	m := NewMetrics(Config{ServiceName: "svc", Enabled: true, Registry: registry})

	require.NotNil(t, m)
	require.NotNil(t, m.HTTPRequestsTotal)
	require.NotNil(t, m.DBConnectionsActive)
	require.NotNil(t, m.ScoreDistribution)
}

// TestConfigFromEnvDefaults verifies default env behavior.
func TestConfigFromEnvDefaults(t *testing.T) {
	t.Setenv("METRICS_ENABLED", "")
	t.Setenv("METRICS_SERVICE_NAME", "")

	cfg := ConfigFromEnv()
	def := DefaultConfig()

	require.Equal(t, def, cfg)
}

// TestConfigFromEnvOverrides verifies valid env overrides.
func TestConfigFromEnvOverrides(t *testing.T) {
	t.Setenv("METRICS_ENABLED", "false")
	t.Setenv("METRICS_SERVICE_NAME", "admin-service")

	cfg := ConfigFromEnv()
	require.False(t, cfg.Enabled)
	require.Equal(t, "admin-service", cfg.ServiceName)
}