package metrics

import (
	"testing"

	"github.com/prometheus/client_golang/prometheus"

	healthDomain "proxy-pool/internal/domain/health"
)

func TestDrainCollectorRecordsOnlyFixedReasons(t *testing.T) {
	registry := prometheus.NewRegistry()
	collector, err := NewDrainCollector(registry)
	if err != nil {
		t.Fatalf("NewDrainCollector() error = %v", err)
	}
	collector.ObserveDrain(healthDomain.DrainReasonUnhealthy, 3, 2)
	collector.ObserveDrain(healthDomain.DrainReasonUpstreamDisabled, 2, 1)
	collector.ObserveDrain("invalid", 9, 9)
	collector.ObserveDrain(healthDomain.DrainReasonUnhealthy, 1, 2)

	assertMetricValue(t, registry, "proxy_pool_controller_drain_candidates_total", map[string]string{"reason": "unhealthy"}, 3)
	assertMetricValue(t, registry, "proxy_pool_controller_drains_started_total", map[string]string{"reason": "unhealthy"}, 2)
	assertMetricValue(t, registry, "proxy_pool_controller_drain_candidates_total", map[string]string{"reason": "upstream_disabled"}, 2)
	assertMetricValue(t, registry, "proxy_pool_controller_drains_started_total", map[string]string{"reason": "upstream_disabled"}, 1)
}

func TestNewDrainCollectorReusesRegisteredCollectors(t *testing.T) {
	registry := prometheus.NewRegistry()
	first, err := NewDrainCollector(registry)
	if err != nil {
		t.Fatalf("first NewDrainCollector() error = %v", err)
	}
	second, err := NewDrainCollector(registry)
	if err != nil {
		t.Fatalf("second NewDrainCollector() error = %v", err)
	}
	first.ObserveDrain(healthDomain.DrainReasonUnhealthy, 1, 1)
	second.ObserveDrain(healthDomain.DrainReasonUnhealthy, 2, 2)
	assertMetricValue(t, registry, "proxy_pool_controller_drain_candidates_total", map[string]string{"reason": "unhealthy"}, 3)
	assertMetricValue(t, registry, "proxy_pool_controller_drains_started_total", map[string]string{"reason": "unhealthy"}, 3)
}