package providerhealth

import (
	"sync"
	"testing"
	"time"
)

func TestTrackerOpensAndRecoversCircuit(t *testing.T) {
	now := time.Date(2026, time.August, 6, 0, 0, 0, 0, time.UTC)
	tracker := New(Options{FailureThreshold: 3, OpenDuration: 30 * time.Second, Now: func() time.Time { return now }})
	key := RouteKey{ModelID: "openai/test", ProviderID: "primary", WireAPI: "responses"}
	for _, status := range []int{503, 429, 504} {
		tracker.Observe(key, Observation{StatusCode: status, Latency: 100 * time.Millisecond, Failed: true})
	}
	if !tracker.CircuitOpen(key) {
		t.Fatal("circuit did not open after consecutive retryable failures")
	}
	snapshot := tracker.Snapshot()
	if len(snapshot) != 1 || snapshot[0].State != "open" || snapshot[0].AvailabilityPercent != 0 || snapshot[0].CircuitOpenUntil == nil {
		t.Fatalf("unexpected open snapshot: %+v", snapshot)
	}
	now = now.Add(31 * time.Second)
	if tracker.CircuitOpen(key) {
		t.Fatal("circuit did not permit a recovery attempt after cooldown")
	}
	tracker.Observe(key, Observation{StatusCode: 200, Latency: 50 * time.Millisecond})
	snapshot = tracker.Snapshot()
	if snapshot[0].State != "healthy" || snapshot[0].ConsecutiveFailures != 0 || snapshot[0].LastHealthyAt == nil || snapshot[0].HeaderLatencyEWMA < 50 {
		t.Fatalf("unexpected recovered snapshot: %+v", snapshot[0])
	}
}

func TestTrackerConcurrentObservations(t *testing.T) {
	tracker := New(Options{FailureThreshold: 1000})
	key := RouteKey{ModelID: "model", ProviderID: "provider", WireAPI: "chat_completions"}
	var group sync.WaitGroup
	for index := range 200 {
		group.Add(1)
		go func(failed bool) {
			defer group.Done()
			tracker.Observe(key, Observation{StatusCode: 200, Latency: time.Millisecond, Failed: failed})
		}(index%2 == 0)
	}
	group.Wait()
	snapshot := tracker.Snapshot()
	if len(snapshot) != 1 || snapshot[0].Attempts != 200 || snapshot[0].RecentSamples != recentWindow || snapshot[0].AvailabilityPercent < 0 || snapshot[0].AvailabilityPercent > 100 {
		t.Fatalf("unexpected concurrent snapshot: %+v", snapshot)
	}
}