package agent

import (
	"context"
	"net/http"
	"net/http/httptest"
	"reflect"
	"testing"
	"time"
)

const page = `<!doctype html><html><head><TITLE> Shop - Willkommen </TITLE></head>
<body><h1>Hallo</h1><h2 class="fuss"><a href="/impressum">Impressum</a></h2></body></html>`

func healthServer(t *testing.T, status int, body string, delay time.Duration) string {
	t.Helper()
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if delay > 0 {
			select {
			case <-time.After(delay):
			case <-r.Context().Done():
				return
			}
		}
		w.WriteHeader(status)
		w.Write([]byte(body))
	}))
	t.Cleanup(srv.Close)
	return srv.URL
}

func TestCheckHealth(t *testing.T) {
	ok := healthServer(t, 200, page, 0)
	tests := []struct {
		name string
		url  string
		spec HealthSpec
		ok   bool
	}{
		{"nur Status", ok, HealthSpec{ExpectStatus: 200}, true},
		{"Titel passt (Leerraum, Großschreibung des Tags egal)", ok, HealthSpec{ExpectStatus: 200, ExpectTitle: "Shop - Willkommen"}, true},
		{"Tag mit Text, verschachtelt", ok, HealthSpec{ExpectStatus: 200, ExpectContains: &ContainsSpec{Tag: "H2", Text: "Impressum"}}, true},
		{"falscher Status", healthServer(t, 500, page, 0), HealthSpec{ExpectStatus: 200}, false},
		{"anderer erwarteter Status", healthServer(t, 204, "", 0), HealthSpec{ExpectStatus: 204}, true},
		{"Titel weicht ab", ok, HealthSpec{ExpectStatus: 200, ExpectTitle: "Wartung"}, false},
		{"Text fehlt", ok, HealthSpec{ExpectStatus: 200, ExpectContains: &ContainsSpec{Tag: "h2", Text: "Datenschutz"}}, false},
		{"Text im falschen Tag", ok, HealthSpec{ExpectStatus: 200, ExpectContains: &ContainsSpec{Tag: "h1", Text: "Impressum"}}, false},
		{"Zeitüberschreitung", healthServer(t, 200, page, time.Second), HealthSpec{ExpectStatus: 200, Timeout: Duration{50 * time.Millisecond}}, false},
		{"nicht erreichbar", "http://127.0.0.1:1", HealthSpec{ExpectStatus: 200}, false},
	}
	for _, tt := range tests {
		if tt.spec.Timeout.Duration == 0 {
			tt.spec.Timeout = Duration{2 * time.Second}
		}
		tt.spec.URL = tt.url
		err := checkHealth(context.Background(), http.DefaultClient, tt.spec)
		if (err == nil) != tt.ok {
			t.Errorf("%s: err=%v, erwartet ok=%v", tt.name, err, tt.ok)
		}
	}
}

// Ausfall erst nach N Fehlschlägen in Folge, Erholung nach einem Erfolg –
// gegen Flattern.
func TestHealthTracker(t *testing.T) {
	var tr healthTracker
	steps := []struct {
		ok      bool
		changed bool
		down    []string
	}{
		{true, false, nil},
		{false, false, nil},
		{true, false, nil}, // Zähler zurückgesetzt
		{false, false, nil},
		{false, true, []string{"shop"}},
		{false, false, []string{"shop"}},
		{true, true, nil},
	}
	for i, s := range steps {
		if changed := tr.report("shop", 2, s.ok); changed != s.changed {
			t.Errorf("Schritt %d: changed=%v, erwartet %v", i, changed, s.changed)
		}
		if got := tr.down(); !reflect.DeepEqual(got, s.down) {
			t.Errorf("Schritt %d: down=%v, erwartet %v", i, got, s.down)
		}
	}

	tr.report("a", 1, false)
	tr.report("b", 1, false)
	if got := tr.down(); !reflect.DeepEqual(got, []string{"a", "b"}) {
		t.Errorf("sortiert: %v", got)
	}
	tr.retain(map[string]bool{"b": true})
	if got := tr.down(); !reflect.DeepEqual(got, []string{"b"}) {
		t.Errorf("nach retain: %v", got)
	}
}