package obs

import (
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"

	"github.com/go-chi/chi/v5"
)

func TestMiddlewareRecordsMetrics(t *testing.T) {
	reg := NewRegistry()
	r := chi.NewRouter()
	r.Use(reg.Middleware)
	r.Get("/x/{id}", func(w http.ResponseWriter, _ *http.Request) { w.WriteHeader(http.StatusNoContent) })
	r.Handle("/metrics", reg.Handler())

	// One 2xx (204) request through the instrumented route.
	w := httptest.NewRecorder()
	r.ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/x/123", nil))
	if w.Code != http.StatusNoContent {
		t.Fatalf("route status: got %d", w.Code)
	}

	// Scrape metrics. The scrape itself is recorded only after it returns, so its body reflects just the
	// prior /x request.
	mw := httptest.NewRecorder()
	r.ServeHTTP(mw, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	body := mw.Body.String()

	for _, want := range []string{
		`mm_http_requests_total{class="2xx"} 1`,
		"mm_http_request_duration_seconds_count 1",
		"mm_http_request_duration_seconds_bucket",
		// in flight reads 1 here: the scrape itself is the in flight request, so assert presence not value.
		"mm_http_in_flight_requests ",
	} {
		if !strings.Contains(body, want) {
			t.Errorf("metrics output missing %q\n---\n%s", want, body)
		}
	}
}

func TestPoolStatsGauges(t *testing.T) {
	reg := NewRegistry()
	reg.SetPoolStats(func() map[string]float64 { return map[string]float64{"app_total": 3} })
	w := httptest.NewRecorder()
	reg.Handler().ServeHTTP(w, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	if !strings.Contains(w.Body.String(), `mm_db_pool{stat="app_total"} 3`) {
		t.Errorf("pool gauge missing:\n%s", w.Body.String())
	}
}